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TT3 theorhetical, what would you build

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trigger

so now that we are underway with the new TT1-2-3 rules. How have things been shaking out? particularlyTT3? lots of TTs cars bumped down, and TTA cars forced up to play in the same class. Personally I am in a TTA C5Z, playing in TT3. I do okay unless the vorshlag mustang shows up. but it is a very fun class because it tends to be the largest. there is always enough folks in it for tires.

 

 

FYI what I currently have. C5Z = 3275/350 = 9.35, no aero. on 315s. 3275/(315x4) = 2.60lbs/mm tire to weight

 

The vorshlag mustang that likes to put 2-3 seconds on me. great driver on pimp suspension and sticker 315's help too. (correct me if I am wrong and you see this terry)

3800/425 = 8.94 lbs/HP power to weight

-.5 aero = 8.44

+.65 for porkiness = 9.09

3800/(315x4) = 3.0lbs/mm tire to weight

 

 

but I digress. so I was just brainstorming ideas. if I had a pot of gold and wanted to build a car for the class, what do I think would be a ringer? What do you guys think would be the ringer for TT3?

 

So here is what I am thinking. Lotus Exige S. bolt ons, pulley, tune, etc ~ 247WHP (seen this on a dyno). weights in at 2050 so ~2250+/- wet with me in it. and the car wont take the aero hit becaue its OEM. and it makes 100lbs of DF at 100mph. run 245/275 hoosier A6's (fenders may need some modification). and ofcourse, as much pimp suspension as you can throw at it.

 

2251/247 = 9.11 (true power to weight)

-.45 for lightness = 8.66

+.4 for <275 DOT tires = 9.06 (adjusted power to weight)

 

and tire to weight = 2251 /(2x245+2x275) = 2.16lbs/mm

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trigger

for a cheaper version of the same thing. you could easily get a turbo miata to make that power and weight and ride on 275's. however it would have to take the hit for aero.

 

another idea the turbo cars can do is thoes programmable boost controllers. they can tune for a flat HP curve. i.e. 300HP at every RPM, by varying boost. that could be a big advantage. or just overwhelming for tires?

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modernbeat
...The vorshlag mustang that likes to put 2-3 seconds on me. great driver on pimp suspension and sticker 315's help too. (correct me if I am wrong and you see this terry)

3800/425 = 8.94 lbs/HP power to weight

-.5 aero = 8.44

+.65 for porkiness = 9.09

3800/(315x4) = 3.0lbs/mm tire to weight...

 

That's about right.

 

We've discussed this in house at Vorshlag and you actually have close to our choice for a ringer TT3 car. I'd use an upgraded fastback rather than a FHC/Z06 to get the better aero from it.

 

All the specs can help choose a car, but it's chassis tuning and driver development that will help the most. Getting the most from the tires you have is the number-one priority.

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Varkwso

C5Z chassis is hard to beat and it is a well developed race car.

 

C6 and C5 coupes may have a mild aero edge, maybe, but they still have a well developed chassis.

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Varkwso

Detuned C6Z is interesting also.

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sfteague

Sitting here drinking my kool-aid, I'm hoping someone will say E46 M3

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modernbeat
Sitting here drinking my kool-aid, I'm hoping someone will say E46 M3

 

Well, for better or worse we are building one. Though it may end up in a higher class than TT3. Where's the "must be brain damaged" smiley?

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sfteague
Sitting here drinking my kool-aid, I'm hoping someone will say E46 M3

 

Well, for better or worse we are building one. Though it may end up in a higher class than TT3. Where's the "must be brain damaged" smiley?

 

I only throw it in because of the "if you had a pot of gold" statement made in the first post

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kbrew8991

Win the lottery option - Cayman

Realistic option - Corvette hatch

 

Boosted Lotus on 245s for the ratio bump could be interesting as well.

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Fair
Sitting here drinking my kool-aid, I'm hoping someone will say E46 M3
Well, for better or worse we are building one. Though it may end up in a higher class than TT3. Where's the "must be brain damaged" smiley?

Jason is referring to our LS1-powered E46 BMW that is being built for NASA TT (and GTA and Pikes Peak). Bimmers work so much better with domestic V8s...

 

_DSC7557-S.jpg DSC_6435-S.jpg

 

We don't know where it will end up in TT (TT1? TT2? TTR?) but it might start in TT3, later this year, at least until the real motor goes in.

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clydesdale

Can that be done without modifying the OEM sub-frame?

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Fair
Can that be done without modifying the OEM sub-frame?

Yep, our LS1 swaps are always a bolt in...

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trigger

agreed. C5Z is a potent car for the class. I am held back by the fact that mine is a street car. and I don't have a pot of gold to dump in it either. if I had the $ to pimp out the suspension and run a more aggressive alignment (compromise of a street car) and mount sticker tires every time, I think it would be a tough car to beat. of course I'm sure there is plenty of time a better driver could find too.

 

so you don't think the lightness of an exige at the same power to weight would be more potent? interesting.

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drivinhardz06
Detuned C6Z is interesting also.

 

This

 

I don't think people realize the strength of the C5/C6 isn't the car itself (yes they are an excellent platform out of the box). Where it shines is the aftermarket, massive "toy" stores of real race parts. Not ebay wings and splitters, we are talking real world ALMS Factory, Europe GT, World Challenge/Grand Am bits - carbon bodies, real aero, suspension bits, and fairly accessible data from established race teams. I would say you could probably rival all that with the 911 race car variants, but you are talking a three fold increase in price.

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kbrew8991
so you don't think the lightness of an exige at the same power to weight would be more potent? interesting.

On smaller tracks where top end speeds aren't huge - sure. At a certain point it becomes hp vs aero, not weight, in acceleration though. Though at ~2000ish lbs, 245s are going to be enough tire, and you're going to want the additonal bump in whp to help on top end against stuff like Terry's car at 3800lbs and corresponding BIG whp #. Could be enough to not get killed in straightaway handling and be close enough to claw the time back in cornering & braking.

 

Of course I'm broken and try and go fast with as little hp as possible it seems so grain-of-salt away.

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sfteague

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drivinhardz06
At a certain point it becomes hp vs aero, not weight, in acceleration though.

 

I think a lot of folks don't consider this, this is absolutely true, and on a car with aero, I think folks would be surprised at how "slow" of speed that crossover point is.

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sfteague
At a certain point it becomes hp vs aero, not weight, in acceleration though.

 

I think a lot of folks don't consider this, this is absolutely true, and on a car with aero, I think folks would be surprised at how "slow" of speed that crossover point is.

 

Meaning that good aero can stick the weight to the ground if you can get it moving fast enough?

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kbrew8991

forward acceleration, not lateral.

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trigger

I actually did think about that. just didnt mention it. the corvette is nice and slippery, but bigger than an exige. the lotus has a huge Cd, but is itty bitty. so when I did the math, the CDA of both is about the same. so thats a wash. now throw a mustang in the mix, woah!

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jrlz0306
agreed. C5Z is a potent car for the class. I am held back by the fact that mine is a street car. and I don't have a pot of gold to dump in it either. if I had the $ to pimp out the suspension and run a more aggressive alignment (compromise of a street car) and mount sticker tires every time, I think it would be a tough car to beat. of course I'm sure there is plenty of time a better driver could find too.

 

so you don't think the lightness of an exige at the same power to weight would be more potent? interesting.

 

I run a street C5Z06. Coilovers, A6's, APR wing/splitter and I drive to the track. Aggressive alignment doesn't seem to effect tire wear much. Some people get excessive wear with too much toe out in front.

You can do it. Not fully prepped but can be competitive locally.

 

 

------

John

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Fair

I think aero is a major player at the higher speed tracks, but it doesn't hurt having downforce at the ECR/MSR/slower speed tracks either. The main problem we have is that the Mustang is rear traction, and the fact that the shape of the car is more akin to a brick...

 

_DSC4512-X2-M.jpg

 

There are a lot of vertical surfaces on the front, and a lot of height to the car, compared to a C5 or C6 coupe.

 

CIMG3332-M.jpg

 

Having owned several Corvettes, including the C6 Z51 above, I can attest to their "high speed abilities". That car would do 120-175mph sprints like nothing else. Pushing the S197 to the same speeds takes a lot longer, even with nearly 75 more whp. Add in the extra drag from the wing and splitter and it only gets worse. But at TWS, where we were touching 165 mph in the Mustang, I had the wing at a high AoA, to keep the rear planted accelerating through T2 and T1 and going onto the main straight. Otherwise it would put the rear 315 A6s into spin mode. More wing adds more drag, and that hurt our speeds on the straights. Its a give and take.

 

DSC_1017-S.jpg IMG_1726-S.jpg

 

The car needs more mechanical rear grip (at this power level and weight), and Hoosier makes a fix for that. Problem is, the 345mm wide Hoosier doesn't fit the car without some sheet metal surgery. Unlike a C6 Z06, which can swallow 355s. We tried the 345/35/18 on the rear (as seen in the two pictures above), but they rubbed badly both inside and out. If Amy would let us cut the fenders on the Mustang we'd flare the back and run that wider tire (and likely need less rear wing) but it's her daily driver car and she won't let me cut any sheet metal. It makes me crazy.

 

DSC_0045-M.jpg

 

So we stick with the narrower 315/30/18 Hoosier or 315/35/18 Kumho V710 (which we have won with many times, and they last a good bit longer), which barely fit under the unmodified fender contours, and run more rear wing to compensate. The pictures above show a rear spoiler, which we had to use in the SCCA autocrossing class, which this car was originally built for. Eventually I'm going to wear her down and we can do some real NASA TT worthy mods to try to make this stick axle pig quicker. The rear wing was a first step, but we have much more we could do (real aero, wider tires, better weight balance, etc). Will it ever be competitive with a similarly NASA TT prepped Corvette? I don't think so.

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trigger

terry, you should make a trek to road atlanta. im curious to see how well you would do against the C5Z mafia over there.

 

well, as for me, I just ordered some custom valved bilstiens. and I been noticing some clunking, I discovered the bushings on my front LCA's walked over to one side, leaving bare metal on the opposite. so a poly bushing upgrade will be on order soon. and I have been running a T1 front bar. i assumed since the car came OEM with a sagger, that the understeer from a big front bar would be offset by 315 square. well it is kinda pushy, you can see it if anyone watched my vid from NOLA. so, I am going to grab a C6Z rear bar to match the front. so my car will be a little less stock for the next round.

 

ADD version >>> I got better shocks, bushings, and swaybars coming. yay!

 

here is a pic of my bushings after the NOLA weekend.

601806_547169478666553_730320865_n.jpg

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braknl8
terry, you should make a trek to road atlanta. im curious to see how well you would do against the C5Z mafia over there.

 

He'd kill 'em. Those guys are sloooooo....

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Fair
terry, you should make a trek to road atlanta. im curious to see how well you would do against the C5Z mafia over there.
He'd kill 'em. Those guys are sloooooo....

As much as I'd love to "pop up to Road Atlanta" to go spar with TT3 Corvettes, we're going to use the July-August "NASA Texas summer break" to develop the car a bit more + work on our E46 LS1 car.

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