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Unread 05-26-2015, 12:19 PM
Fair!'s Avatar
Fair! Fair! is offline
I blame the internet
Join Date: Jul 2004
Posts: 6,093
Default Re: Vorshlag Budget TT Build: Project DANGER ZONE

Project Update for May 26th, 2015: Its been pretty busy around Vorshlag and I've been buried in the CNC room, but with a bit of extra help in there for the summer I can finally sneak into my office and write a few project build forum updates.

This Week at Vorshlag for May 8th, 2015 - including a bit on the C4 at the 6:40 mark

We haven't had time to work on the C4 other than extracting the drivetrain. Again, we only work on our "shop cars" when we have a gap in our customer work schedule, which hasn't existed. So I snuck the C4 in line for a few hours of shop time and had the guys yank the motor and it was sent off to be rebuilt. We've also had more conversations about "the internet protest", which was actually FIVE things, and we're aiming to fix all of those before our next event. I will go over some upcoming car prep and document the issues of the protest in great detail.

Motor Rebuild Time

Yep, after 24 hard years this old LT1 has seen better days. Too much crankcase pressure makes for excessive blow-by and smoke, which precludes us from making a lap without a black flag. There's not much to share in this section other than the motor is finally out and shipped to the engine shop, and how that came to be.

With but 6 weeks until our next event, I couldn't wait for an opening in the shop schedule any longer, so I asked Brad and Ryan to get that LT1 out of the car as quickly as possible on May 6th. Within a few hours the drivetrain was out and the motor was on a pallet, ready for truck shipment the next day.

After pulling the driveshaft, c-channel drivetrain brace, transmission and shifter out, they could finally lift the motor out of the engine bay. Its a TIGHT fit in there, with a cross brace right next to the front balancer. Its almost impossible to stab the motor and transmission into the car tied together, unlike in some other cars.

A sharp-eyed reader noticed the "throttle body airfoil" (top right), which we don't have points for. Its coming out.

The motor was stripped down to the basic long block, it was bolted to an engine stand I had built years ago for easy GM V8 transport. Many LS1s have been shipped on this shipping stand, but this is the first LT1. This frame was then bolted/strapped to a pallet, wrapped in plastic, and all 480 pounds was shipped to the guys down at HK Racing Engines in La Grange, Texas. One thing someone on Facebook noticed in a picture I posted (and called me to warn me about, thanks Dave!) when the engine was out was an aftermarket "airfoil" in the throttle body. With a 24 year old car, sometimes a previous owner's mods get missed. No excuses - this airfoil is coming out. We want this car to be PERFECTLY legally. Squeaky clean. As a business owner in motorsports I cannot afford to be caught cheating in competition, and I'd rather lose a race than knowingly break a rule.

HK has pulled the top of the motor apart and told me "it all looked fine". By now they should have some .020" overbore replacement pistons, rings, bearings and valve springs ordered, which should freshen things up a bit. I think they will find some broken piston rings when they tear the bottom end apart, since we noted a lot of scoring in the bottom of a few cylinders as well as "too much" ferrous metal grit in the bottom of the oil pan.

I'm going to clean the living snot out of the engine bay while the motor gets rebuilt

Erik Koenig is a master engine builder, and also a damned good racer. I raced with him for a couple of decades and he knows how to read a rulebook. I sent him the pertinent pages, we discussed what we can do (and what we cannot) in TTC, and he's all over it.

Our TT3 prepped Mustang sold in June 2015

Problem is that I didn't give him a lot of time, so making the June 15th Hallett event is going to be tight... if the motor isn't back in by then I'm NOT racing our TT3 Mustang at Hallett (it is very much for sale!) Yes, this TT3 car has won 4 tires every time we have shown up to a NASA event in the past 2 years, and did so again a few weeks back at TWS - winning by a huge margin after taking only a single lap on Sunday - but that car is out of competition, for me. If you know of anyone potentially interested, please send them to this link - Thanks!

No more "back up ride" in the TT3 Mustang, as it still has perfect paint that I want to protect for the next owner!

So, I've already used my "4 drops" in TTC for the regional championship, so if we miss this June Hallett event in #DangerZone I'm just not going to worry about TTC regionally for this year. With our summer break coming, we won't have another NASA Texas event after Hallett before NASA Nationals East, so I will have to go to an out-of-region NASA event or use non-NASA events to test the car before Nationals. I've still not had more than 2 laps in a row in this car all season, dang it.

Changes Planned To Be 100% Legal

I mentioned a couple of the things that I was told were protested against #DangerZone in my last post, but have since seen a more complete list of items in an email from Greg Greenbaum, NASA's National TT director. In private correspondence Greg passed on an alarming number of things that some reader of this build thread wrote in about to protest (five).

As I mentioned before, some are cage issues - three in fact. One was a very picky, gray area issue that I have been "all but told" is allowed on this car, for safety concerns in this narrow cabin. As I showed in a previous post (again, I am hiding nothing) parts of the roof side bars next to my head are a hair outside of the window plane, but otherwise they'd be inside my helmet. I can't sit any lower without going through the floor, either. Its this way or no cage, and after my accident last year I'm not keen on driving un-caged race cars.

We always tie in both sides of "NASCAR" door bars to the frame, for symmetry and safety. But in NASA TT-letter classes it is +2 points

The other two cage issues are shown to be illegal in the rules... sort of. First, the passenger side door bars clearly cannot be tied to the frame even though they are allowed on the driver's side (up to 3 places). I read the rule wrong, where it said "drivers-side" I thought "both sides", stupid mistake on my part. It still seems odd that the cage rules would make for an "asymmetrically safe" cage. So our plan of putting a passenger seat in this car and taking riders is out, since we can't make the right side of the cage as safe as the left without taking +2 points (and bumping up a class). Easy fix with a saw and grinder.

The third and most unclear of the cage protest rulings has to do with the two optional tubes that the TT cage rule above states can be added to the firewall or foot well areas. Our two tubes are apparently placed too high to be called "tire intrusion protection" (but the rule says nothing about tire intrusion, of course, that is something you have to assume). What the rules wording does say doesn't match of what the rules makers meant, however, as I'm told after this ruling that it should read as follows:

Originally Posted by what they really meant to write
"Two additional attachment points for either two foot-well bars or two bars to the front firewall BELOW THE TOP OF THE TIRE (one on each side) may be added without TT Modification Point assessment".

The "below the top of the tire" bit was what I was told is inferred in this rule. Shame on me for not knowing that. The two NASA race directors I showed this cage layout to thought we had them in the optimum place, but they were also wrong. So apparently we have to read and interpret the rules then always ask for a clarification for anything (or risk a DSQ at an event). You were warned: there are the written rules and then there are the unwritten rules. Again, this is an easy fix - We will cut those two tubes out, move them down below the top of the tire, weld them back in place, and then be double-secret legal.

Item four brought up in the protest was our upgrade to 1996 Corvette Base Trim Level front 13" disc brakes, over the 1992-95 BTM 12" front discs. Again, we did our homework and found that all 1996 model Corvettes came with the 13" diameter fronts, which used to be an optional upgrade on base coupe Corvettes from 1989-95 under the Z07 or Z51 options. But since this car is listed on the same line as all 1992-1996 Corvettes, non-LT4, non-ZR1, we can "update" to the 1996 base trim brakes for zero points (normally +2). Yes, its a loophole but hundreds of racers look for loopholes to exploit - that's called racing. Luckily the National office agreed with our documentation here and disallowed that particular protest.

Shocking Thing About OEM Shocks

The last issue that is being ruled against (item 5) has to do with the OEM Bilstein vs the replacement Bilstein dampers we used, which I am gonna lose. See, we don't have the points left in our TTC class points budget to add better dampers (+2), so we elected to stick with the OEM units and changed spring rates instead at +3. That was a gamble that some thought was strange, since we could have done double adjustables shocks (which we sell) for +2 points instead of springs (we don't sell the VBP spring).

This was how the car looked while cornering on the B6 Bilsteins + 245 R7s + stock bars and springs.

After driving the car on the 245mm Hoosier R7s at MSR-Houston (above), with the B6 Bilsteins and stock springs, then looking at these pictures... I felt the car had too much roll and dive. Sure, we could have gotten some of that dialed out with adjustable shocks ($3350 MCS monotube TT2 doubles), but probably not as much as I'd like. Tripling the front and doubling the rear spring rates made a bigger change, in my view (and I drove it this second way at MSR-Cresson), so we took a gamble and went that route. I will just have to deal with the less-than-ideal damping offered by the stock replacement Bilsteins. Ideally, of course, we'd change BOTH the spring rates and shocks. That is if we had the points budget, which in this case we just don't. ALL the rest of our points are for the tires - because TIRES ALWAYS MAKE THE BIGGEST IMPROVEMENT IN LAP TIMES.

Tires matter SO MUCH and virtually everything we do to the suspension is just to keep the tires happy

So, let's look at the OEM shocks. As I stated before, this 1992 model Corvette base model coupe came with Delco-Bilstein 46mm piston monotube dampers at all four corners, and amazingly the 24 year old original shocks were still on this car when we got it. Unfortunately, two of them were blown, which is to be expected after nearly two and a half decades of use and abuse. So we purchased replacement Bilsteins as close as can be purchased today, and put them on for a "zero point" replacement.

Wrong. Not the original dampers, not legal. This is what the ruling was on item 5.

continued below

Last edited by Fair!; 08-05-2015 at 06:17 PM.
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