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Unread 09-09-2015, 07:36 PM
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Fair! Fair! is offline
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Default Re: Vorshlag 2002 BMW E46 325Ci - Daily/Track Car - Project Jack Daniels

continued from above

What is still strange to me is how well the S52 (above left) engine did in our 1997 M3. We ran it in at least 100+ autocrosses, often with 3 drivers per day (me, Amy, and the previous car's owner) and always touching the 7500 RPM redline, for over 6 years. All that was done was a welded stock oil pump nut to the shaft. That's it. Stock balancer, stock 100K+ mile engine, and it was tracked several times during that period as well. It has the same, goofy chain driven oil pump as the M54, too. Maybe the E36 M3 engine just had some better mojo than the non-M E46 engine? Again, I think these oil pump issues were more "old balancer failure" related than just "oil pump drive" or "too many RPMs" related. But I'm not taking any chances....


I have been alluding to prepping this car for a NASA Time Trial class, and there are a number of choices we can make now that effect the build down the road. Do we want a "BIG" tire with no aero, or a narrower tire with aero added? Our 2001 330Ci was built around a 285 tire and stock aero, and it did all right - but that was back in 2010. And the work required to fit those tires (flares) was extensive...

Do we want to stick with the 325's M54B25 engine or go to the more powerful M54B30 from the 330? What about the larger 330 brakes? We can convert this car to a real 330 fairly easily - we have a 330 in the shop that could donate the front and rear brakes, the engine is an easy internet search + a day of labor to swap, etc. But the engine swap is not likely to happen, because it would require more parts to be swapped to be considered a "base trim level" 330, and would require a new initial base classing. So let's ignore that for now and just think "E46 325".

There are a lot of ways to build a given car for a specific NASA TT class, and you can change mods down the road if you want to try a different setup and stay classed the same. Let's take a quick look at how NASA Time Trial "Letter Classes" work, because this might be new to some of you. First, you look up your car's "Initial Base Classing" starting on page 19 of the NASA TT rules. I have that broken down for the E36 and E46 BMW models in the chart below.

The TT rules have one giant listing for all cars that have ever been given an initial base class. If you look at the list of BMWs, they are sorted very poorly, so I took out the basic E36 and E46, M and non-M cars, resorted them, and created the graphic above. That means our 325Ci is classed in TTF with two stars (**).

Next we make a list of the modifications we want to do and tally up the points assigned to each mod, also shown in the TT rules, starting on page 29. We use a custom spreadsheet that we have created and it automatically sums all of the "mod" and "base" points. There are also a lot of "zero point mods", which are upgrades or changes allowed across all classes without any mod points. Camber plates, lightweight flywheels, upgraded brake pads, upgraded motor and transmission mounts, etc. Those are all listed on page 35 of the 2015 TT rules, and we will utilize many of these "free mods" for sure.

Next we look at the total points and see if we have "bumped up a class", which is explained below. Since we're starting with 14 penalty points in TTF, that means we only have 5 points left to stay in TTF, which isn't a lot. We will obviously be modding this car beyond that, and go to at least TTE class if not TTD for the final build.

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.
We usually do this a little backwards when starting a new build. The first thing I do for any car we might prep for NASA TT is look at the base classing, base minimum weight, any penalty points (* = -7, ** = -14), and the base tires and power-to-weight ratios of the initial and final classes. I figure out what final class I want to be in, then figure out what mods I can do for the points allowed. These TT classing calculations involve many variables, and we usually make a dozen or more calculations to get to our initial "class build-up".

I think the final build will end up in TTD, so that means 59 points worth of mods. Then take out the initial two star (**) penalty of -14 points, so we have either 5 points of mods we can use and stay in TTE or 45 points worth of mods for TTD. That's a pretty good number, and we should be able to do all of the suspension, tire, exhaust, cold air, and aero mods we want for that and stay in TTD with a reasonably competitive car. I guess that's what we shall see!

We have made a pair of detailed build plans, and which one we choose will depend on the results of the early upgrades, which are in both plans. We have to know "where we will end up" because so many items that need to be repaired have to be done with either stock parts or upgraded parts depending on the final points tally, and hence the final TT class build. Here's our initial TT running points tally with the current Dunlop 245mm street tire package (Not what we have planned for the final TTD setup, but its just an example of what we've done and what points the car has accrued).

With up to 19 points we could have stayed in TTF, 20-39 points is TTE, 40-59 points is TTD. 23 points now = TTE legal

If you look at the initial classing of the 325 vs 330, the 325Ci has a better (aka: lower) base class (TTF**) than a base trim level 330Ci in (TTE) as well as a lower minimum weight (3197 pounds for the E46 325, 3285 pounds for the E46 330) but not really if you look at it's base class "base tire size" (TTF = 215mm, TTE = 235mm). Both the 330 and 325 would likely end up in the same class no matter how you build them, and the 325 Coupe will have one single, solitary point advantage over the 330, if we build them the same way. And still strapped with a smaller displacement engine (184 hp vs 225 hp), all due to the TTF** base classing. So we have some number crunching to do, to see if we should stick with the 197K mile 2.5L inline-6 and small 325 brakes or "base upclass" and make this car into a 330Ci, with the larger brakes, more powerful motor, and TTE starting class's larger starting tire size (235mm).

There are also some year-to-year upgrades that we will try to find - like the points free 1996 model brake upgrade we did on our TTC 92 Corvette, since they lump all 1992-96 LT1 Corvettes into the same base class. Again, we are using a 2002 325Ci, which is lumped in with all 2001-06 325 BMWs. So we can mix and match major parts from the Base Trim Level 325i or 325Ci models for any of those 6 years, for no points. Or if we upclass this to a 330, we can use the BTM parts from those year 330Ci or 330i cars. I doubt there's a super secret ringer part within the 2001-06 325 or 330, but we shall see (haven't found it yet).

330 brakes are a cheap upgrade for the 325, but they cost +2 mod points (the same as a real BBK)

The big question is do we want to make this a small tire/aero build or a larger tire/stock aero build. I know the big tire build worked before, but we've learned a lot about aero since 2009, too. I need to figure out how many points the M3 bumper is going to cost me. The 330 ZHP has no base class, so using the ZHP bumper or 235hp engine is verboten, without taking points. I will talk a LOT more about bumpers next time - I wrote a lot about that already, but this post got too long.


Just like I (retroactively) did in Round 1 of posts and work to this car, I have tallied the costs for this second round of mods and repairs. I am beginning to regret buying a car with so many problems, dents and miles, but I suppose that's the case with any used BMW you buy that has problems.

Virtually all E46 cars you are going to find will need much of this work, especially the guibo, cooling system and worn bushings here and there. We've still just scratched the surface of needed repairs, and there are many leaks to fix, bushings to replace, and tuning issues to work through. I have yet to even test drive the car after the cam sensor and manifold replacement, so who knows if those even worked?


There's plenty of other parts to fix: old transmission shifter feels as loose as you could imagine, the motor and trans mounts are shot, the rear diff bushings are clunking, the front strut mounts are gone, the sunroof is stuck, and it badly needs new front lower control arms and LCA bushings. Not to mention the rear subframe bushings + chassis repair it will surely need at the mounting points. Pretty much all of those "Repairs" will be taken care of during the track upgrade preparations.

So Round 3 will have some more exciting "Race parts" instead of these boring "old car problems". I wrote a bunch more but I will save it for next time, as it has to do with classing choices and such. There are a few parts I am going to order now that will dramatically change our path forward with this project, so tune in next time. Much bench racing to do... which is half the fun of building a TT car.

Until next time,

Last edited by Fair!; 09-10-2015 at 10:14 AM.
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