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2007 Exige S Competitive in TTA?


Rick Apichairuk

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I'm thinking about trying out the NASA Time Trials with my 2007 Exige S. If I read the rules correctly, it is classified in TTA. It's a fully loaded Exige S (Track Pack, LSD, Traction Control, Touring Pack). Are any points assessed for those factory options? I don't plan on making any modifications other than the free ones. In fact, I will probably only do tires and wheels.

 

My other concern is whether or not it is actually competitive in TTA. There seems to be quite a lot of stiff competition in this class. The 996 Turbo and C5 Z06 definitely seem to have the upper hand on tracks with long straights. It's clear that the C5 Z06 dominated the 2006 National Championships. Did anyone run an Exige last year in TTB? Do you guys think the Exige S will be competitive in TTA?

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Factory options are ALWAYS assessed points for every car. However, depending on tire choice, there will probably be a fairly large tire size credit.

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there was an regular Exige driven in TTB at Nationals last year, but iirc the guy was still getting used to the car and off the pace by quite a bit

 

the tire rules really hurt alot of the Z06 guys, so I'd expect them to be slower this year

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Factory options are ALWAYS assessed points for every car. However, depending on tire choice, there will probably be a fairly large tire size credit.

 

So let me see if I have this right. The Exige S starts in the TTA class. It weighs 2077 lbs as listed by the factory. I'm unsure if that includes all the options or not. Lotus claims 218 horsepower. This gives it a weight/power ratio of 9.5275299. The weight of 2077lbs gives it a power modifier of -1.15.

 

The widest tire I plan on running is 225mm. This is a 70mm difference from the class limit of 295mm which effectively gives me a 19point credit. This also has a power modifier of +0.8.

 

So with all the power modifiers, the adjusted weight/power ratio is:

 

9.53 (rounded up)

-1.15 weight

+0.8 tires smaller than 245 DOT approved

------------------------------------------------

9.18 adjusted weight/power

 

9.18 is far from the TTS weight/power ratio of 8.70:1 so I am safely in TTA.

 

The Lotus Track pack which includes:

 

Adjustable Bilstein Dampers with Remote Front Reservoirs and Threaded Spring Perches. Compression and Rebound are Adjusted Simultaneously with Single Knob. 5-Way Adjustable

Front Anti-Sway Bar. Rear Track Control Arm Brace Reinforces Suspension Mounting Points. Fittings in Seat Belt Support Structure Allow Bolt-In Harness Bar.

 

So the adjustable suspension with remote reservoirs adds 10points. The LSD gives me another 3points and the traction control which gives me another 3points. The front sway bar adds 2pts. Springs +2 points even though they aren't mentioned in option??

 

+07 Points for showing up (Greg can you explain this?)

-19 Tire credit

+10 Adjustable dampers

+02 Springs

+03 Traction Control

+03 LSD

+02 Front Sway Bar

+07 Treadwear 50-90 tires

------------------------------------

+15 points

 

19 points before being bumped - 15 points = 4 points to spend

 

 

If I correctly assessed the points, I have 4 points to play with before being bumped into TTS. Is this correct?

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Assuming you stay above the 2077 minimum weight with driver (should not be a problem) and you use the stock A048 tires

 

To the best of my limited knowledge:

 

Exige S Base class TTA*

 

 

 

Extra points for * +7

Treadwear 50-90 tires +7

70mm less treadwidth -19

Shock (ext. res.) +7

Springs +2

Swaybar +2

LSD +3

TC +3

Suspension brace:

Bump steer +2

Hemi joints +3

 

Total: +17

 

Of course the LSD and TC are a big help, but the only difference in the TP swaybar is more holes are drilled in it for adjustability.

You could buy a stock swaybar, get rid of 2 points and spend lots of money on better shocks and springs and be at only +15!

 

You could replace the Suspension brace with stock ball joints and save 5 points also.

 

Then you could upgrade to slick DOT tires (max 225) for only 3 more points or max 245 for 9 more points.

 

Then..... till you get to +19 and have a maximum prepared car.

 

Now, you only have to worry about your checkbook and being a competitive driver.

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Where did you get bump steer and heim joints from? Are those options on the Exige S?

 

Now, you only have to worry about your checkbook and being a competitive driver.

 

Yes those things are critical. But I just want to make sure that I have a chance. The car itself is large determining factor.

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The rear suspension brace is designed to reduce squirm in the rear tires (toe in or out). The closest any description of upgrades to this is a bump steer kit on the current rules. Unfortunately, Lotus uses hemi joints as part of this upgrade. Even worse, the hemi joints have a thick plastic insert between the hemisphere and outer body and are not metal to metal contact. So, the brace is more for saftey and only reduces squirm by a small margin in my opinion. If I was classing this upgrade I would count a bump steer kit as +2 and have a seperate rule for bump steer kits with hemi jonts (like yours) for +3. Luckily, I am not in charge so I don't have to deal with this.

 

Remember, this is free advice and you only get what you pay for.

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"9.18 is far from the TTS weight/power ratio of 8.70:1 so I am safely in TTA...."

 

 

I believe it is the adjusted ratio that will get you bumped. So you are closer than you think. If you bust the 9.18 then you are actually bumped to TTU and out of TTA and TTS.

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9.18:1 is already the adjusted weight:power ratio. 8.7 is the limit for TTS right? Is TTU lower or higher?

 

Is there anything in the formula to account for lack of overall horsepower and therefore a lack of overall top end speed?

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Hmmmm, You might want to disregard my previous post about being bumped. I'm confusing myself now......

 

The one thing I am confident about telling you now is that it most likely won't be a factor for you. The HP is based on RWHP so I'm guessing that you would make around 190ish on the Dyno if your car is rated at 218. The other thing to consider is that your weight will be measured after a session including the driver so you should be fine.

 

Now , time to look at the rules again about the AR 8.7.....

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Hmmmm, You might want to disregard my previous post about being bumped. I'm confusing myself now......

 

The one thing I am confident about telling you now is that it most likely won't be a factor for you. The HP is based on RWHP so I'm guessing that you would make around 190ish on the Dyno if your car is rated at 218. The other thing to consider is that your weight will be measured after a session including the driver so you should be fine.

 

Now , time to look at the rules again about the AR 8.7.....

 

You confused me too!

 

Anyone have a definite answer on the HEIM joints and the bump steer. Am I really going to be assessed points for those items?

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interesting topic here.

 

the 8.7 as i read it, and as the TTA-TTF classing form reads

 

Note: Any car exceeding the Adjusted Wt./Power Ratio limit of 8.7:1 used to classify TTS/TTU vehicles

automatically moves up to the TTS/TTU/TTR competition classing system

 

TTU: is 5.5

 

So thats fairly close.

 

My question, how do you determine the cost of a suspension, if it's factory? (ie: how would you determine the cost to determine +7 or +10?)

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Yes. I researched that mod a few months ago, and that is how it ends up in the assessment.

 

Greg, please explain why you classify this as a bump steer kit. It's only purpose is to disperse the load over the rear bulkhead to prevent inner ball joint failures. It uses the factory mounting points and is only used to adjust rear toe the same way as stock. There's no adjustment to take into account changes in ride height.

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Yes. I researched that mod a few months ago, and that is how it ends up in the assessment.

 

Greg, please explain why you classify this as a bump steer kit. It's only purpose is to disperse the load over the rear bulkhead to prevent inner ball joint failures. It uses the factory mounting points and is only used to adjust rear toe the same way as stock. There's no adjustment to take into account changes in ride height.

 

YEAH!? What he said!

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Because the references that I was sent by the competitor requesting information about this modification stated that part of it's function was for bump steer.

 

Perhaps he can post those references again.

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I think I am the one who asked you to research this. I never claimed it reduced bump steer. I do not believe it makes one difference in the way the car drives or functions (but it might). The only reason I installed the chassis brace was for increased safety. Others (owners that have no empirical proof) have claimed that the rear of the car feels more planted because the rear end has less squirm. They claim that the extra support maintains a more consistent toe under side load (not from suspension travel)since the inboard toe link ends are held in double shear instead of a cantilever setup. Rick claims “and is only used to adjust rear toe the same way as stock.â€

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So let me see if I have this right. The Exige S starts in the TTA class. It weighs 2077 lbs as listed by the factory. I'm unsure if that includes all the options or not. Lotus claims 218 horsepower. This gives it a weight/power ratio of 9.5275299. The weight of 2077lbs gives it a power modifier of -1.15.

 

The widest tire I plan on running is 225mm. This is a 70mm difference from the class limit of 295mm which effectively gives me a 19point credit. This also has a power modifier of +0.8.

 

So with all the power modifiers, the adjusted weight/power ratio is:

 

9.53 (rounded up)

-1.15 weight

+0.8 tires smaller than 245 DOT approved

------------------------------------------------

9.18 adjusted weight/power

 

9.18 is far from the TTS weight/power ratio of 8.70:1 so I am safely in TTA.

 

The Lotus Track pack which includes:

 

Adjustable Bilstein Dampers with Remote Front Reservoirs and Threaded Spring Perches. Compression and Rebound are Adjusted Simultaneously with Single Knob. 5-Way Adjustable

Front Anti-Sway Bar. Rear Track Control Arm Brace Reinforces Suspension Mounting Points. Fittings in Seat Belt Support Structure Allow Bolt-In Harness Bar.

 

So the adjustable suspension with remote reservoirs adds 10points. The LSD gives me another 3points and the traction control which gives me another 3points. The front sway bar adds 2pts. Springs +2 points even though they aren't mentioned in option??

 

+07 Points for showing up (Greg can you explain this?)

-19 Tire credit

+10 Adjustable dampers

+02 Springs

+03 Traction Control

+03 LSD

+02 Front Sway Bar

+07 Treadwear 50-90 tires

------------------------------------

+15 points

 

19 points before being bumped - 15 points = 4 points to spend

 

 

If I correctly assessed the points, I have 4 points to play with before being bumped into TTS. Is this correct?

 

If I am assessed the 5 points (+2 for bump steer and +3 for heim joints) for the rear suspension brace that will put me in TTS with the car as is from the factory. Does someone really think that an Exige S from the factory (no modifications) is competitive with a C6 Z06, Ferrari Enzo or a Porsche 959? If this is really how the Exige S is going to be classified, I think it will alienate many Exige S owners from competing in NASA TT.

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I still think you're in TTA because of that rear bump steer issue. In my opinion both the N/A Exige and Exige S should not be given the 7 point handicap. My '06 with a few mods, mainly suspension and exhaust, is now classed TTA along with the supercharged '07's. Only difference being I'll be able to run Hoosiers if I want. That's assuming you can drop the 2 pts for rear bump steer.

 

On the other hand look at Slinkard in his S2000. He was in TTC running times that would have won TTB and probably TTA at most tracks. Why? Because he's a hell of a driver and know's how to set up the car. I know the Exige is capable of better times than I as a driver right now. That's the fun of it. After all, its more fun driving a slow car fast than a fast car slow.

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In my opinion both the N/A Exige and Exige S should not be given the 7 point handicap.

 

I don't understand this either. Can someone please explain the criteria used to do determine which cars are given a 7 point penalty? I would understand if the car was dominant in a given class in the prior year(s). This is not the case with either the Exige or Exige S.

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In my opinion both the N/A Exige and Exige S should not be given the 7 point handicap.

 

I don't understand this either. Can someone please explain the criteria used to do determine which cars are given a 7 point penalty? I would understand if the car was dominant in a given class in the prior year(s). This is not the case with either the Exige or Exige S.

 

 

That might be something to do with the car being 2077lbs. This year, all light weight cars were dinged additional points to make up for the advantage of being so light to begin with.

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So the adjustable suspension with remote reservoirs adds 10points. The LSD gives me another 3points and the traction control which gives me another 3points. The front sway bar adds 2pts. Springs +2 points even though they aren't mentioned in option??

 

+07 Points for showing up (Greg can you explain this?)

-19 Tire credit

+10 Adjustable dampers

+02 Springs

+03 Traction Control

+03 LSD

+02 Front Sway Bar

+07 Treadwear 50-90 tires

------------------------------------

+15 points

 

19 points before being bumped - 15 points = 4 points to spend

 

 

If I correctly assessed the points, I have 4 points to play with before being bumped into TTS. Is this correct?

 

If I am assessed the 5 points (+2 for bump steer and +3 for heim joints) for the rear suspension brace that will put me in TTS with the car as is from the factory. Does someone really think that an Exige S from the factory (no modifications) is competitive with a C6 Z06, Ferrari Enzo or a Porsche 959? If this is really how the Exige S is going to be classified, I think it will alienate many Exige S owners from competing in NASA TT.

 

I don’t see how your car is in TTS from the factory. The way I figure it you are only at +12 or +17.

 

First, your shocks probably fit in the +7 category. They are one way adjustable shocks with threaded bodies and remote reservoirs on only the front shocks. From the rules:

2) Non-OEM shocks/struts/dampers with a retail price of greater than $600 per unit ($2400

total) or $750 each if sold only as a coilover with spring included ($3000 total). Also

“Piggybackâ€

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If I am assessed the 5 points (+2 for bump steer and +3 for heim joints) for the rear suspension brace that will put me in TTS with the car as is from the factory. Does someone really think that an Exige S from the factory (no modifications) is competitive with a C6 Z06, Ferrari Enzo or a Porsche 959? If this is really how the Exige S is going to be classified, I think it will alienate many Exige S owners from competing in NASA TT.

 

Put it this way. I've run with a few regular exige owners. Then I saw an exige prepped to T2 rules (struts, no springs, no bars, etc), completely tear everything up on a decidedly horsepower track (sebring).

 

I think it's definatly competitive 100% stock, and even more so when you start to play the points game. it's a hell of a car.

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I would look at your window sticker to check which are truly options. I don’t have an Exige S brochure but the UK Exige S comes with the chassis brace standard. So, you might not have to add those 5 points that you are so worried about. Here is a pdf of the UK Exige S brochure:

http://www.grouplotus.com/media/car/doc/tech_spec/Exige%20in%20Brief%20UK%2007.pdf

 

Actually the suspension brace seems to be part of the "Track Pack" according to the 2007 brochure:

 

http://lotuscars.com/Exige_Spec_Sheet.pdf

 

Track Pack. $2,495

Requires Sport Pack. Adjustable Bilstein Dampers with Remote Front Reservoirs and Threaded Spring Perches. Compression and Rebound are Adjusted Simultaneously with Single Knob. 5-Way Adjustable

Front Anti-Sway Bar. Rear Track Control Arm Brace Reinforces Suspension Mounting Points. Fittings in Seat Belt Support Structure Allow Bolt-In Harness Bar.

 

The brace does not do anything to adjust toe in or toe out as it relates to suspension ride height. If I understand this correctly, it is technically not a bump steer kit.

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