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  #11  
Unread 10-23-2015, 11:25 AM
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Default Re: Vorshlag 2002 BMW E46 325Ci - Daily/Track Car - Project Jack Daniels

Looking forward to the future update when you give up and get a lower mileage 330Ci.
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  #12  
Unread 10-24-2015, 07:42 AM
rkneeshaw rkneeshaw is offline
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Default Re: Vorshlag 2002 BMW E46 325Ci - Daily/Track Car - Project Jack Daniels

This thing is going to be better than a lower mileage 330Ci by the time Terry is done with it

Looking forward to when he gets to working on the headers
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Unread 11-03-2015, 06:33 PM
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Default Re: Vorshlag 2002 BMW E46 325Ci - Daily/Track Car - Project Jack Daniels

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Originally Posted by Redwood View Post
Looking forward to the future update when you give up and get a lower mileage 330Ci.
We have been quietly searching for this, actually....



Bought this Hellrot red 2001 BMW 330Ci 5-speed last night. Already working on it. Will update this thread with this change shortly...
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Unread 11-03-2015, 11:56 PM
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Default Re: Vorshlag 2002 BMW E46 325Ci - Daily/Track Car - Project Jack Daniels

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Unread 11-04-2015, 07:16 AM
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Default Re: Vorshlag 2002 BMW E46 325Ci - Daily/Track Car - Project Jack Daniels

Hey that thing will need quality headers too!
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Unread 11-04-2015, 11:19 AM
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Default Re: Vorshlag 2002 BMW E46 325Ci - Daily/Track Car - Project Jack Daniels

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Originally Posted by rkneeshaw View Post
Hey that thing will need quality headers too!
Yes it will....



We tried to find some of the old Magnaflow headers but they are out of production and gone. So we will make our own E46 M54 long tube headers.
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Unread 11-05-2015, 10:26 AM
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Default Re: Vorshlag 2002 BMW E46 325Ci - Daily/Track Car - Project Jack Daniels

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Originally Posted by Fair! View Post
Yes it will....



We tried to find some of the old Magnaflow headers but they are out of production and gone. So we will make our own E46 M54 long tube headers.
Yeah I think its impossible to find them anymore.

I believe a magnaflow rep said they were way too expensive to make like that so they switched to the stock "saucer" shaped collector to keep costs down.

It's too bad, because that design looked like a winner. I haven't been able to find any before/after dynos though to see how they stack up against stock or catless headers.

I can't wait to see what you guys come up with!
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Unread 11-17-2015, 03:37 PM
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Default Re: Vorshlag 2002 BMW E46 325Ci - Daily/Track Car - Project Jack Daniels

Project Update for November 17th, 2015: It has been an interesting few weeks and this E46 Daily Driver / NASA TT project has made a dramatic turn.... for the better! We've switched horses mid-stream, as it were: there's a shiny Hellrot red 2001 330Ci now in our driveway and the little gray 325Ci is getting replaced.



Why the chassis change? For one, the 330 ends up being classed in NASA TT better than the 325 - I will explain that below in excruciating detail. Secondly, this 330 is cleaner and has more power than the 325 ever will. We have already started some initial repairs on the 330 and we are finishing up a few loose ends on the 325 before it gets sold. All of this is covered in this post, and at the end I will discuss some changes to the NASA TT rules for 2016 that effect TT1/2/3, but which will probably impact the TT-letter classes in a year or two.

Sadly, the red car doesn't even have a name yet.

YOU GET WHAT YOU PAY FOR

Remember this same section from last time? How I was expressing regret over purchasing JackDaniels, our little 325Ci here? As we dug into this chassis it was a little more worn and a little rougher than I had hoped for.



Sure, we've fixed almost everything having to do with the brakes and suspension, but look at how much $ was sunk into repairs. My "Round 3" of repairs tally (see above) for the 325Ci takes the total spent on parts and chassis to a staggering $4622 - and we still have a few items to wrap up before it will be sold (I'm not selling a broken car). Yea, I cannot hope to even get $4600 for this (not to mention the 18.5 hours we spent doing the work) so I'm going to lose my shirt selling the 325. See why it would have made sense to buy a $3000-5000 car in better shape now?



Why did we buy this car, with as many miles and worn bits as it had? I have explained that before in this thread, but basically it was the lowest priced E46 5-speed coupe available after we sold my wife's 740iL. While we could have waited, during those weeks or months of looking she would have been daily driving the F350 dually, which was all kinds of bad idea. But this decision was still short-sighted, and maybe you folks can learn from our mistake here.


Going from the M54B25 to the M54B30 made for a 25% increase in power, stock for stock

The repairs on JackDaniels have spanned 3 months and we're almost done with them, but its still a 325 and not a 330. The 325 has a 2.5L six and the 330 has a 3.0L six - which has a 41 hp stock rated increase over the smaller motor. That's a 25% power increase! There are also numerous other differences, like the bigger brakes, a higher (yet better) base classing in NASA TT/PT, and some other small differences.

I had talked about converting the 325 to a 330, but upon closer examination it looked like more work than it would be worth - plus there are some unknowns that could make for "Protest Bait" at NASA events. Right after purchasing this 325 I had quietly been searching for a cleaner, lower mileage 330 5-speed, hopefully a coupe, and hopefully something painted Hellrot red.



Damn if if this exact set of "wants" didn't pop up in my local Craigslist searches a couple of weeks ago! Amy and I went and looked at this car on a rainy day and test drove it, and the 25% power increase over the 325 was very apparent. The body was straighter, the paint was in better shape, and the interior was nicer. It wasn't perfect - the brakes were worn, it had some suspension clunks I could hear in the test drive, and of course it flashed a CEL within seconds of starting it up - E46s love to light up that Check Engine Light!



I had a friend run the VIN while we discussed the purchase and that showed not one but two insurance claims in its past, both apparently front end hits (with one of them also tagging the rear bumper cover, which has also been repainted). The damage and repairs were very apparent, and not bad work for the most part. The frame rails were straight and the unibody had no damage, just superficial stuff. Most of its life was in Texas (not a rust belt state), so that's good. The two wrecks and the odometer's 160K miles logged impacted the price, but snagging this 2001 330Ci 5-spd for $3500 made it all worth it.



This red E46 isn't perfect, but overall it clean and in nice shape, especially considering what we paid for it. The exterior, interior, wheels and power are a big step up from what we started with on the 325. It was also the only 330 5-spd coupe I've found for under $6000 in many weeks of looking locally. Sure, there are often deals 5 states away, but this car was only 8 minutes away, so going to look at it didn't gobble up hours of driving.



Upon closer examination I saw something during the negotiations with the seller: this E46 also needs a front core support assembly. I detailed in a previous post where I found them for $54 shipped, so another is on order. This one is torn more than bent, probably happened during the recent front end hit (hooked a trailer hitch on a truck or something), and you can see the issue in the image above. The hood is straight, the headlights work and are even aimed well, which is all good.



The 330 has super dark "limo tint" on all of the windows, even a big strip along the top of the windshield. Not only is this illegal, it is so dark you cannot drive the car at night with the side windows up, so that's all coming off. Track Cars should not have tinted windows - anything that limits your 360° visibility on track is unnecessarily dangerous.



The interior is nice enough except for the A-, B- and C-pillar covers and headliner). The sunroof is - you guessed it - also broken. We will use the S2R Tuning sourced fiberglass E46 sunroof delete panel on this car, to gain headroom and to remove that 33 pounds up top. The stock black leather power seats are in nicer shape than the 325's, so those will go into JackDaniels before it sells (and the pair of COBRA race seats into this 330). The 330's factory steering wheel and shifter will also be swapped into the 325, too.



I might even swap the 5-spoke wheels from the 330 to the 325 to help it sell. These are factory 17x7.5" front, 17x8.5" rear and are in excellent shape. Whatever we don't plan to keep on the red car long term and would help sell the 325 gets swapped.

330 REPAIRS BEGIN

Some small issues made this 330 "slow to sell" and also helped me push the seller's numbers down $1000 from the asking price (they wanted $4500). I pointed out the front end damage and the VIN history to the seller, noted the CEL, and discussed the suspension clunks and bent rear control arms that I could see. We got a decent deal but didn't exactly steal the car - as it had a few things we needed to repair straight away.



I've said it before but I will say it again - tow truck drivers are the worst. Why do they always want to put their tie-down hooks right in the middle of BMW rear lateral control arms?? These arms cannot take any fore-aft forces, especially hooked right in the middle, as they are made for lateral suspension loading only. When these guys strap chains on these arms they get bent quickly, like this...



Another new pair of OEM replacement Lemforder lateral arms were sourced and Olof once again installed these onto the red 330, just like he did on the 325. It is bound to happen on a used E46, but at least they aren't expensive.



The bent arms probably tweaked the rear alignment, no? The inboard lower bushings are replaced when you do these arms, by the way. To replace these you have to remove the inner mounting bolts. To gain access for this you have to unbolt the differential housing and move it out of the way a bit (see below).



During my test drive, our inspections up on the lift, and during the LCA install, we all noted "worn differential mount bushings". These were clunking away during quick shifts on my test drive, and Olof could put a pry bar on the diff and move it against the bushings a lot. Another very common failing of an older E46.



Luckily the 325's diff bushings aren't all that bad, so the new Powerflex Race polyurethane differential mount bushings we sourced for that car will go into this 330. We will also take the Powerflex Race subframe bushings allocated for that car and install them on the 330 as well. Now that these lower arms are back to stock and straight we can focus on other immediate fixes.



The CEL codes pointed to a non-functional air pump, so Brad dug around for a bit to find the issue. Solenoid could be jumped and it would come on, the wiring was good, just wasn't getting a strong signal from the DME. This pump is supposed to come on after start-up and run, injecting air into the manifolds to "light-off" the catalysts.



Cold start emissions get borked when this doesn't work. Normally just the pump is bad, or the air valve at the manifold, but those seemed to work.



I took the 330 by briefly to see my friends at Autobahn Service Center in Plano for a second set of eyes to diagnose the CEL issue. They have the right computer equipment to cycle things through the DME and they found that the secondary air pump wasn't cycling. They also noted that one of the idler pulleys was howling, which we also heard. First step was to replace ALL of the idler pulleys, tensioners and both serpentine belts.



The air pump had 160K miles on it so we went ahead and purchased a new one, just to be safe (this will remain an emissions legal street car, after all). All three rubber bushing mounts for the pump were hard and broken, so there were also replaced. The air hose shown above was badly cracked so it was replaced, as were some of the small vacuum hoses that trigger this system. We are waiting on the vacuum switch that is on the back of the cylinder head to arrive, then it will be installed, hopefully fixing this system and thus the CEL. Then we can get it inspected!



Like virtually all BMW models that are 14 years old, this one has some seals and gaskets underhood that have hardened, cracked, and are now leaking fluid. There's some oil residue underneath, but not nearly as bad as the 325.



Next week we will replace the valve cover gaskets and remote oil filter housing gaskets on both E46 cars, to remove the cracked gaskets that each car has and hopefully stop the fluid leaks. The 330 will also get new spark plugs, cabin air filter, and the air pump vacuum switch. I will detail all of the costs for parts and hours spent on the initial 330 repairs in my next update, since we're sort of in the middle of those.

325 VS 330 - NASA TT CLASSING

If you have no interest in NASA Time Trial classing, feel free to skip down past this entire section. NASA TT-Letter classing is somewhat complicated and a bit confusing, which is partly how I made the mistake of purchasing the wrong car initially (325) for a TTD build. Initially when we thought about this E46 project I was looking for another E46 330, because we built that model into a TTD and ran it in NASA TT events twice, and set TTD track records at both events. The funniest part was that car wasn't really built for TTD, it was supposed to be an autocross car. It was only accidentally a decent TTD car (but a relatively poor autocross car).



One thing we did differently on that blue 330 was run all stock aero. That saved a lot of "mod points" for tire width, which we spent almost entirely in 285 mm Hoosier R6 tires. Again, this was really because our autocross set-up was much more dependent on tire width, and the TTD setup was more of an afterthought (all we did was switch from 285 mm Hoosier A6 to 285 mm R6). That car was built back in 2009 and since then I've come to appreciate reducing drag and making downforce a lot more, so we're building the current E46 330 around a 245mm R7 tire and a wing + splitter + vented hood.

continued below

Last edited by Fair!; 11-17-2015 at 03:43 PM.
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Unread 11-17-2015, 03:38 PM
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Default Re: Vorshlag 2002 BMW E46 325Ci - Daily/Track Car - Project Jack Daniels

continued from above

This time around we started off with the goal to build a TTD car, so priorities are also different. I will explain "the holy trinity" of road course priorities in a section below.


One of the two times we ran this autocross car in TTD it was done on 265 street tires, as shown above

Still, I rushed the purchase of the E46 this time around and we initially settled for the 325 we found for less $$. Impatience costs money because now we are starting over with the "right" E46. I talked briefly about my NASA TT classing concerns with the 325 in my last (September 8th) thread update. It wasn't until after we bought the 325 that I ran all of the TTD classing calculations and permutations, then I figured out the mistake I had made - the 330 is actually classed better for the end goal of TTD than the 325. It has more points to play with AND a lot more power.



The BMW E36/46 base classing list (from 2015 NASA TT rule set) above might not make it obvious that the 330 is better classed, at first glance. The 325 starts out in TTF** with an assigned 3197 pound minimum weight and the E46 330 starts in TTE with a 3285 minimum. So you'd think that, once you move either car all the way up to TTD, the "lower" base classed 325 has more points to play with and a lower minimum weight, too. The numbers seem to show that, since one build is jumping up TWO classes (59 points worth of mods) and the other only ONE class up (39 points).

Quote:
8.3 Up-Classing System (TTB-TTF only)

Modifications and Point Assessments: If a car accrues 20 or more points it will be bumped up in Class. There is no limit—a car with a high level of modifications might move up several Classes.

20 thru 39 points - Up ONE Class
40 thru 59 points - Up TWO Classes
60 thru 79 points - Up THREE Classes
80 thru 99 points - Up FOUR Classes
100 thru 119 points - Up FIVE Classes

One (1) asterisk * on a base class assignment denotes a 7 point initial assessment, and two (2) asterisks ** denotes a 14 point initial assessment that is added to the total number of Modification Points to determine the final competition class.
  • E46 325, base TTF** jumping to TTD = 45 points (A two class jump yields 59 points, minus 14 base class "penalty points")
  • E46 330, base TTE jumping to TTD = 39 points (39 points yields for a single class jump)
  • This gives an extra 6 points of modifications to get from their respective base classes up to TTD, in favor of the 325...

So 45 points to work with on mods for the 325 is better than 39 points on the 330, right? Wrong. There are still two differences on the TTF** classed 325 that gobble up points we have to account for. First is that the base tire size is different for each base class - doesn't matter what the factory tire sizes are, it is what the initial base Letter class is assigned with.

Quote:
The following tire sizes will be used as the base tire size for each Base Class for all vehicles regardless of their OEM tire size(s) or their Final Competition Class. All vehicles in a given base class may use this tire size (or smaller) without a points assessment:

TTB: 265mm
TTC: 255mm
TTD: 245mm
TTE: 235mm
TTF: 215mm
TTG: 195mm
TTH: 175mm
So the E46 330, which has a base class in TTE, starts with a 235mm base tire. The E46 325 is classed in TTF, so it starts with a 215mm tire. I have run the numbers and we think that a 245mm tire is ideal once we end up in TTD (which I will explain later, see "the holy trinity of road course prep"), but that tire size costs points on each car differently.



Not to mention that not all 245 tires are the same width, but that's not the point here. Let's just look at why the same 245mm width tire for a TTD build costs 6 more points for the E46 325 than the E46 330...

Quote:
Tire width points assessed or points credited are determined by the difference between the width of the largest tire on the vehicle and the assigned base tire size as follows:

Equal to or greater than: 10mm +1, 20mm +4, 30mm +7, 40mm +10, 50mm +13, 60mm +16, 70mm +19, 80mm +22, 90mm +25, 100mm +28, 110mm +31
  • E46 325, 215mm to 245mm needs +30mm in width = 7 points
  • E46 330, 235mm to 245mm needs +10mm in width = 1 point
  • E46 330 in TTD on 245mm tire has a net gain of 6 points
This takes 6 points away from the E46 325 relative to the E46 330, each with the same end goal TTD class - since it didn't have to burn 6 points going from 215->235 base tire size. So remember: a lower base class doesn't always give you more points. The next advantage is the 330's larger factory brakes...



Since I've already tracked a 330 with the OEM sized rotors extensively I know that they can work well, and with good pads and cooling I'm fairly certain we can run this TTD build on the 330 brakes. The base e46 330 has larger brakes than even the M3 version of the E36. The smaller E46 325's rotors, however, are fully 1" smaller in diameter than the E46 330 at both ends, which means they might be marginal. We had already upgraded the JackDaniels 325 to use the larger 330 front brakes as a "cheap big brake upgrade", which costs +2 class points (same as going to any BBK). But now with the E46 330 using the same 330 rotors and calipers get's to keep those 2 points because they are the factory Base Trim Level brakes for all 330s.

So if we add up the relative points advantages from the starting tire size (+6) and now the "free" big brakes (+2), then subtract out the 6 point difference in the 325 and 330 points (45 - 39) to get to TTD, we still have a net gain of 2 points for the 330 over the 325 to get to TTD prep.


Baseline dyno of the 325 (at left) and my former 2001 330 (at right) with a cheap eBay header

Then we look at the fact that the E46 330 has a 225hp engine (M54B30) vs the 325's 184 hp engine (M54B25), so that's a gain of 41 hp. The chassis dyno charts above are from our 325 at left and my old blue 2001 BMW 330 at right. The E46 330 dyno'd (my blue 2001 33) had a very crappy eBay header and an even worse tune, but you can still see the relative differences: 211 whp for the 330 and 162 whp for the stock 325 (49 whp diff).

So the 330 is ahead on points and has a 25% head start on horsepower. Win-Win.... right? And yes, this difference did come with a financial cost, as most 330s are going to sell for more than 325s, like this one did ($3500 for the 330 vs $1800 for the 325, a $1700 bump), but this 330 has fewer miles and fewer problems. And look how much fixing problems has cost on the 325.

TTB 10.50:1
TTC 12.00:1
TTD 14.25:1
TTE 16.50:1
TTF 19.50:1

The last issue had to do with getting the E46 325 to the Power-to-Weight ratio limit (P-to-W) for TTD class (14.25:1 pounds per whp), which is shown above. So we always try to get TT-Letter cars down to their assigned minimum weights (with driver), because that doesn't cost any points. To the E46 325 (3197 pounds) and E46 330 (3285 pounds) would be easy to hit those minimums, but with the M54B25 engine in the 325, there was going to be an epic struggle to get to the class P-to-W limit. Then there is an often overlooked series of adjustments to TT-Letter class P-to-W number from Appendix B....



This is just a summary - you can click the image above for the FULL list of Appendix B loopholes. There are modifiers for body type (4 door and station wagons), transmission (sequentials take a hit), drivetrain (AWD takes a hit, FWD gets a bonus), even your final competition weight (under 3200 pounds takes a hit, over 3400 pounds gets a bonus).

And the "weight modifier" portion of Appendix B (see below) reminded me that the 325 run at minimum listed weight of 3197 (3 pounds below 3200) would have to take a -0.05 hit. Obviously it makes sense to run 3 pounds heavier than that minimum to avoid a weight modifier.



This is why "running lighter than minimum" can hit you THREE ways.... First, with a lighter given weight you have to make less power at the same P-to-W ratio. Then if you run under minimum you have to take points for every 15 pound increment under the listed weight. Thirdly, you take a modifier hit for all weights below 3200 pounds. Yes, even if your car's assigned Minimum Weight is below 3200, you still take the modifier hit. So before you think about running lighter than Base Class number, or any car lighter than 3200 pounds, DO THE MATH.


Check the published width numbers for various tire options, too!

This was a somewhat long explanation, but this is why SO many TT-Letter class cars run a 245mm tire - that size or smaller allows them to gain +0.8 in their P-to-W ratio, to allow for more power legally at the same weight. This is how we built our TTC Corvette (which runs on a 245mm Hoosier R7 tire), and it makes a BIG difference (TTC's ratio is 12.0:1 vs the 11.2:1 we run the C4 at). That assumes you can even MEET the revised horsepower goals on the adjusted P-to-W ratio, with the class mod points you have. Let's calculate the modified P-to-W for both TTD E46 BMW models we're looking at.

E46 TTD build starts with 14.25 (TTD limit) - 0.8 (245 DOT tire modifier) = 13.45:1 P-to-W

And yes, I understand the Appendix B says "+0.8" and we just subtracted that bonus from the 14.25 number, but NASA writes the rules and does the calculations backwards. Trust me, I stayed at a Holiday Inn Express, we're doing this right (and will show examples of doing this "the NASA way" below). So with this revised P-to-W limit of 13.45:1 for TTD on a 245mm tire, the two E46 options would need to hit the following wheel horsepower numbers at the base class mandated minimum weights for each:
  • E46 330, 3285 lbs / 13.45 = 244.2 whp max (which we likely can hit with exhaust + CAI + tune on the 3.0L)
  • E46 325, 3197 lbs / 13.45 = 237.7 whp max (doubtful we can hit that in the 2.5L)
So on paper it is possible for the E46 330 to "max the P-to-W", but the 325 looks doubtful, even at a 6whp lower goal. Why? I don't think the M54B25 engine could ever get to 238 which, which is a 77 whp increase over the stock chassis dyno numbers we tested on the 325) without major internal engine mods, which we don't have the points for. the 330's 244 whp goal is only ~35 whp more than a stock M54B30 makes, which I'm confident we can pull off with extensive exhaust, CAI and tuning mods (but no internal engine mods). We have allocated points in our 330 TTD build for these power changes.

Maxing out a car's P-to-W ratio (running at the minimum weight listed and max power allowed by the ratio) is pretty important for lap times. So on top of spending points on tires, suspension, and aero you need to also max out power to hit the limit of the adjusted P-to-W for your class. It isn't even possible in TT-Letter classes for some cars - the factory engine's limitations and class points just don't always allow for it.

For the E46 TTD problem, some might argue to just run the less powerful 325 at a lighter weight, to reach the P-to-W. Main problem with that - going below minimum weight listed for a given car costs points.

Quote:
B. WEIGHT REDUCTION:
Weight reduction points are based on the actual vehicle minimum competition weight (with driver). Removal and lightening of nonessential parts is permitted unless stated otherwise in the rules. Modification of the OEM frame, sub-frame, and floor pan are not permitted (see 5.2.2) Removal or lightening of engine parts is permitted only as listed elsewhere in the TT rules. The exterior surface of the roof, hood, body panels, and doors must remain their BTM size and shape unless listed otherwise in these rules. If the base weight used for base classing purposes (section 5.2.2) minus minimum competition weight (with driver*) is greater than:

5 lbs +1, 20 lbs +2, 35 lbs +3, 50 lbs +4, 65 lbs +5, 80 lbs +6, 95 lbs +7, 110 lbs +8, 125 lbs +9, 140 lbs +10, 155 lbs +11, 170 lbs +12, 185 lbs +13, 200 lbs +14, 215 lbs +15, 230 lbs +16, 245 lbs +17, 260 lbs +18, 275 lbs +19, 290 lbs +20, 305 lbs +21, 320 lbs +22, 335 lbs +23, 350 lbs +24, 365 lbs +25, 380 lbs +26, 395 lbs +27, 410 lbs +28, 425 lbs +29, 440 lbs +30, 455 lbs +31, 470 lbs +32, 485 lbs +33, 500 lbs +34, 515 lbs +35, etc…
So while TT-Letter classes allows pretty liberal weight removal mods without burning "mod points", any time TT-Letter cars are raced BELOW their Base Class stated minimum weight (shown in the base classing list), they have to take POINTS for every 15 pound increment below minimum weights (see chart above). Which means you again miss your P-to-W limit and/or run out of points for proper suspension, aero, power or tire mods.

continued below

Last edited by Fair!; 12-24-2015 at 03:19 PM.
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Unread 11-17-2015, 03:38 PM
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Default Re: Vorshlag 2002 BMW E46 325Ci - Daily/Track Car - Project Jack Daniels

continued from above

This is the Catch 22 for most TT-Letter builds... they aren't all equal because only some cars can get to the class P-to-W limits and still have any points left over for adequate tires and other supporting mods.



In a nutshell THAT is was why our TTC classed 92 LT1 Corvette works so well: first we got the adjusted P-to-W modifier for running a 245mm tire (plus 1 point was gained back because that's 10mm below the TTC class starting tire size of 255mm), which moved the P-to-W from 12.0:1 to 11.2:1... but the Corvette could still hit the P-to-W limit of TTC, even with a bone stock LT1 stock motor. This meant we didn't have to burn class points on exhaust or headers or camshaft swaps or intake mods. We spent ALL of our remaining points on suspension changes (springs at 3 points) and tire compound (R7, 10 points), and it worked out pretty well so far. It is rare that this works this way in TT-Letter classes, which means there is a bias for certain car choices for specific classes, which can limit car model diversity and choices for TT competitors.

Let's do those P-to-W calcs "the NASA way" for our TTC Corvette:
  • Weight is at or above the listed minimum weight of 3203 pounds from the base classing
  • That 3203 number is also just above the minimum "competition weight" modifier numbers, which start at 3200
  • We chose a 245mm width DOT legal tire (+0.8 bonus)
  • The stock engine made 284 whp peak (highest of 3 pulls)
  • 3203 / 284 = 11.28:1 (P-to-W) + 0.8 for (245 tire modifier) = 12.08:1
TTC Class "minimum" P-to-W is 12.0:1, which this car is just a hair over. That's what you want to do - aim for the P-to-W limit and find any modifiers you can to help that ratio along the way. Avoid modifiers that hurt, then use your points to run the best tire compound/width and fix any suspension issues, and add aero if you have any points left.

So long story short DO YOUR HOMEWORK up front when building for a class, make sure to CHECK THE MATH, and PAY MORE MONEY to start with the right car. Lastly, YOU GET WHAT YOU PAY FOR, so don't expect to save money by starting with a high mileage heap that needs a bunch of repairs vs a cleaner/lower mileage car that costs more up front. I just wish I could follow my own advice, ha!

WINNING IS COMPLICATED - THE HOLY TRINITY

The calculations for classing a Letter car was tortuously convoluted. Did you READ all of that crap in the section above?? Look at how much ink was spilled just to explain that a 330 is a better car for TTD than the 325!? The sad thing is I still got it wrong and had to go out and find the right car (330), and I've built a half dozen TT cars for myself and have made worksheets for dozens more for customers, many of which have gone on to be competitive, max point, maxed-out power-to-weight TT Letter cars.

Here is what we feel are the three most important things to winning in a road course setup, specifically TT-Letter classes:

1. Power-to-Weight ratio
2. Power-to-Tire ratio
3. Weight-to-Tire ratio

For NASA-Letter classes we have several things that limit tire width, so we have to keep that in mind. Ideally I'd run a wider tire than we are shooting for here in our TTD E46 330 (245mm) or our TTC Corvette (also 245mm), but the 0.8 P-to-W "bonus" for running 245mm or smaller is too good to pass up.

More tire width will burn up points FAST and we have found that a better tire compound is ultimately more important than running extra tire width, within reason. But if that were not the case, say that TTC became "TT5" (it might someday, read below) and had the ultimate 12:1 P-to-W limit as the lone guiding factor, we'd run more tire width.

Why? A wider tire can make more laps before overheating, lasts longer (wear), and is easier to drive. On the TTC Corvette with the power it makes we can quickly overheat the rear tires, so we use TT strategies to limit laps in any session to 2-3 laps. Running more laps would likely overheat the tires, they get greasy and fall off, then lap times start to slip.

We noticed this running 315mm Hoosier A6 tires on our TT3 Mustang, and after lap 1 the lap times would slow down 1-2 seconds for each successive lap. The tires also liked to run best cold, so that meant the first session of the day was almost always ideal. So it boiled down to one "golden lap" in one "golden session" to shoot for the best time each day, which sometimes made it difficult to get the best lap time out of the car (and subsequently, many of our TT3 records are "soft"). Every once in a while the stars would align, however, like the video below shows.This was 2013, Day 2 at a NASA event at NOLA, when we ran the 315mm tire on the TT3 car.


Day 2, first session, first lap - one shot to get the best conditions

As I mention in the beginning of the video, I knew it would come down to this ONE lap to nail it. It rarely works that way but somehow in that one lap I manged to match the theoretical best lap that the predictive lap timer showed was possible all weekend. That lap record has stood for 2-1/2 years with 3 different NASA groups running the same NOLA course, even after we made the car much faster in 2014 (wider tire, better aero). Since we didn't have any points or tire modifiers on that TT# classed car (the modifiers all go away above max out at 275mm in width for DOT tires), in 2014 we switched to 335mm front and 345mm rear Hoosier A7 tires (with no penalty), which added enough width and heat capacity so so that best laps could be made on lap 1 or lap 2. With the weight that car was run at (3802, to utilize the maximum "competition weight" modifier) it was still easy to overheat the 345mm tire after lap 2 - and that was the biggest DOT tire Hoosier makes.



Just like we used in TT3, up through 2014 the DOT Hoosier A6 was still a fairly low point, attainable tire that was commonly used in TT-letter classes to set track records. This made the "first lap strategies" that much more important in TT-Letter. Thankfully, in 2015, NASA rules makers raised the points up for the Hoosier "A" compound (autocross compound), so much so that it becomes prohibitive to use the A6 or newer A7 compounds. Now the go-to tire for TT-Letter is the more reasonable and less "peaky" Hoosier "Road Race" compound, the R6 and newer R7.

Quote:
1 ) The following DOT-approved R-compound tires: BFG R1S, Goodyear Eagle RS AC (auto-cross), Hoosier A7, Hoosier Wet DOT (if used in dry conditions—see section 5.6), Hankook Z214 (C90 & C91 compounds only) + 22
2 ) The following DOT-approved R-compound tires: Hoosier A6 + 17
3 ) The following DOT-approved R-compound tires and those with a UTQG treadwear rating of 40 or less not otherwise listed in these rules: BFG R1, Goodyear Eagle RS, Hankook Z214 (C71, C70, C51, C50), Hoosier R7
Kumho V710 + 10
4 ) The following DOT-approved R-compound tires: Hoosier SM7 +9
5 ) The following DOT-approved R-compound tires: Hoosier R6, Hoosier SM6 (note: Continental Tire Sportscar Challenge EC-Dry tires (225, 245, 275) OK) +8
6 ) The following DOT-approved R-compound tires: Toyo Proxes RR, Hankook TD +7
7 ) The following DOT-approved R-compound tires and those with a UTQG treadwear rating over 40: Maxxis RC-1 (ex. Kumho V700, Michelin Pilot Sport Cup & MPS Cup 2, Nitto NT01, Pirelli PZero Corsa, Toyo R888, Toyo RA-1, Yokahama A048, etc) +6
6 ) DOT-approved (non-R-compound) tires with a UTQG treadwear rating of 120-200 (examples: Toyo R1R, Dunlop Direzza Sport Z1 Star Spec, Bridgestone Potenza RE070, Kumho Ecsta XS, Yokohama Advan A046 & Neova
AD08, Hankook R-S3, BFG g-Force Rival) +2
9 ) Non-DOT-approved racing slicks +30 (of any origin—re-caps and re-treads are not permitted)
And while there are many other tire models/compound eligible in TT-Letter class, the points they cost and the lap times they can produce just don't seem to be worth the effort. Even the hot "200 treadwear" tires still cost +2, which makes the points not work in their favor compared to a Hoosier R6 (+8 points) or R7 (+10). ALL other tire compounds seem to fall to the wayside when competition gets serious, at least in TTB-TTD. Toyo, Nitto, Maxxis all seem to be hopelessly uncompetitive at the highest levels of NASA TT. The BFG R-1 (+10) is a close contender to the R7, but it has many fewer sizes to choose from and has NO contingency program for NASA TT. The Hoosier contingency program is pretty solid, and is part of why so many racers just ignore all other options - they are fast and you can win 4 tires in a weekend if you have enough competitors in class.

So once you run the numbers and pick your tire width and compound (which locks in your "tire-to-__" ratios), its now time to maximize the Power-to-Weight ratio. Which is simple.

1. Minimizing Weight
2. Maximizing power

Duh.... right? Ultimately you run the least weight, the most power and the most tire, but that "most of everything" formula isn't allowed in TT-Letter, so we work with what we can maximize. Getting down to the minimum weight published in the Base Class listing is what you strive for (with driver and fuel), as I explained before. Going below that minimum isn't worthwhile due to the points its costs.

Maximizing power is a matter of both luck and skill. "Luck" in that you picked the right car that has plenty of OEM power, or potential to make power without too much effort. "Skill" in the way you utilize the points to modify the things you can to get to the max power allowed for your adjusted P-to-W.

That's it. That's the big 3. The rest (aero downforce and brakes and suspension) are smaller gains, but still significant, and on some cars there are deficiencies you need to fix (poor brakes, suspension issues, etc) that will eat up your TT-Letter class points. I could go on but that's enough, so I hope that made sense. This is the strategry we use.

CHANGES ARE AFOOT in TT/ST/PT

The TT1/2/3/U (aka: TT#) classes are SO much simpler to build up than TT-Letter. You don't have to worry about NOT doing some upgrade because you ran out of points. Gone are base classings, points for mods and class bumps, the sometimes impossible struggle to max out a car for the classes' power-to-weight limit with no points left for power mods. You also aren't stuck running the minimum base weight - you can do whatever is allowed within the very loose TT# rules to get down to whatever weight you want, so you can always get your TT1, TT2 or TT3 car to the max P-to-W limit. Unless you suck at math or have no budget.

Time Trial 1 (TT1) = “Adjusted Wt/Hp Ratio” equal to, or greater than 5.50:1
Time Trial 2 (TT2) = “Adjusted Wt/Hp Ratio” equal to, or greater than 8.00:1
Time Trial 3 (TT3) = “Adjusted Wt/Hp Ratio” equal to, or greater than 9.00:1

And that list, ultimately, is the main basis for the TT# classes. The P-to-W calculation is 95% of the class rules. Just like the TT-Letter class Appendix B's list of modifiers, TT# has similar modifiers to that ratio, but ultimately P-to-W is your main guide, goal, whatever. You can remove weight to get there, or add power however you want to get there, but your adjusted P-to-W limit is everything.



That's why our TT3 Mustang worked well - we used some modifiers to get it to 8.8:1 (running it very heavy, over 3801 pounds gained us 0.6!), took the aero penalty for TT3 (0.4 this year), maxed out the P-to-W for TT3, and ran it on the biggest DOT tire Hoosier made (345 Hoosier A7), ran LOTS of aero (to the limit of the rules in several places), kick ass suspension, and brakes that were up to the task. We made it easy enough to drive so a schlub like me could win, then just used some strategies to try to get traffic-free laps. We racked up dozens of wins, set 16 track records this way, and didn't pay for tires in almost 3 years, but always ran on sticker sets (from winnings).

This is almost the level of dedication we are bringing to TTD with this E46 build. Getting the 330 makes this a MUCH easier task, but there are other cars in TTD that can and do hit the max P-to-W limit. But to me, none do it as easily as the E46 330....

CHANGES TO NASA TT/ST RULES FOR 2016

So that was pretty epic explanation and had ALL of my strategies for maximizing a Time Trial build within NASA. I hope it was worthwhile because it took many seasons to learn these tricks. Remember though, the rules change every year and there are more changes afoot for TT-Letter.

These tricks also apply to the wheel-to-wheel (W2W) crossover series called Performance Touring (PT) and Super Touring (ST). In case you didn't know, TTC-TTF classes share the same competition rules as PTC-PTF, and TT1/2/3/U are the same as ST1/2/3/U. The only real difference are the W2W safety requirements. We often see PT and ST cars jump to TT for more chances to win, too.

I have not always seen eye-to-eye with the National TT/ST/PT Director and rules czar Greg G. I grumbled about TT-Letter class rules when we ran our Mustang in TTB (briefly and poorly) and again with all of the Mystery Internet Protest stuff surrounding our TTC build for my 1992 Corvette. Some of the rules in TT-Letter classes just went against basic racer logic.


This is one of the "dyno tricks" that turbo cars are doing in P-to-W classes

Well I think in the long run Greg is moving the complicated rules of TT-Letter classes to the more simplified TT# set of rules for all classes. That's what I've gathered from recent NASAforum posts by Greg G, and follow up letters to various competitors that have been shared. For 2016 the TT3 class is also getting an adjustment to the P-to-W starting points plus changing the way power is measured (average vs peak), which takes out some tricks turbo engines could do to make the same peak power for a LONG range of RPMs (see image above). These changes will likely propagate to TT1/TT2 in 2017 and possibly to TT-Letter also, at some point. I really like the proposed changes, so kudos to Greg. It is a bold move but a necessary one.

ST1/TT1 = “Adjusted Wt/HP Ratio” equal to, or greater than, 5.50:1
ST2/TT2 = “Adjusted Wt/HP Ratio” equal to, or greater than, 8.00:1
ST3/TT3 = “Adjusted Wt/HP Ratio” equal to, or greater than, 10.00:1

You can read the new proposals here and look for these changes and the Letter classes in general to phase over to new TT# classes in 2017, 2018 and beyond. I think the next TT-Letter class to go is TTB, which will likely become TT4. This happened already in 2013 when TTA merged with TTS and became TT3, so there is a precedent. Trust me, the TT# rules are SO much easier to understand and take out a LOT of the inherent car model advantages. TT# gives you more choices, more paths to the end goal (P-to-W), without fretting over damned points.

NASA TT IS STILL FUN!

Please don't take this long explanation of NASA TT and get turned off. It really is worth it, and all of these rules, modifiers, points, and base classings are used to equalize the cars and differentiate the classes. And for the most part they really do work. It only fails when people don't do the math or understand the rules correctly.


NASA TT has big fields, lots of car diversity, and great contingency payouts

If you are thinking of buildings a car around NASA TT rules and are getting confused, CALL US. Jason and I here at Vorshlag can help, and we can steer you towards the best modifiers and tires to use for a given car and end class goal. That's really what you need to decide up front: what car you want to start with and what class do you want to end up in? Knowing that + the type of tracks you frequent, we can help guide you through the class points, the modifiers, and calculations within calculations to get towards the right selection of parts for tracks in your area.

WHAT'S NEXT?

We still have some initial repairs on the 330 to tackle, but they are much less extensive than the 325. And the 325 is getting the some interior and other bits from the red car, plus some other repairs, so it can be sold for a trouble-free daily driver to someone. I will post a CraigsList ad and link it here when its ready, hopefully in a couple of weeks.



I'm more excited than ever to prep the Hellrot 330 Coupe, as I really like the looks of this car and its better chances at a max P-to-W build. So, what do we call this red thing?

Thanks for reading,
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