Few Q's on 3.2 Carrera for autox build
07-24-2009, 06:02 PM
#1
Track Day
Thread Starter
Join Date: Oct 2006
Posts: 24
Likes: 0
Received 0 Likes
on
0 Posts
Few Q's on 3.2 Carrera for autox build
--------------------------------------------------------------------------------
Hello,
The SCCA is putting together a new autcross class called STR. The 80's era 3.2 is the only 911 allowed in the class, along with the Honda S2000, Mazda MX5, Nissan 350Z, and Toyota MR2 Spyder.
I think a 911 would be a really fun car to put together for the class. I've been researching the cars a bit but there is some stuff that you can't get from the spec sheets. Would appreciate any input the community could provide.
Here goes-
1. Engine mods allowed are a cold air intake, headers (must retain cats, but they can be high-flow), cat-back exhaust, pulleys, and ECU tune. Everything else stock. Does 190-200ft-lbs. between 5000 and 6000 rpm as a peak torque range, to the wheels, sound about right? The '88-'89 G50-trans cars all had 3.444 final drive with 2.059 2nd gear right?
2. We're allowed wheels up to 9" wide and tires up to 255 in width. We can roll fender lips and have freedom over ride height and alignment, but can't flare. I don't think fitting the max allowed in the rear will be a problem, but what about the front? Maybe it won't "need" as much in the front but it would be good to know what can be done. This'll be a race car/toy so some rubbing is ok, and it won't need full steering lock. Assume this is a regular narrow-body car, not one with the widebody option.
3. The Club Sport is allowed in. I know finding a real one is basically impossible and turning one into a racecar would be heresy, but we are sort of allowed to do pseudo-conversions in some cases. Are the 911CS engines really any different than the standard 88-89 engines, other than ECU? If you took a regular '88 coupe, removed the AC, sound deadening, rear seat, welded up the sunroof panel (or can you get one without sunroof here?), and swapped in manual windows and locks (and headliner I guess), what big stuff would still be different from a Club Sport? I know there was little stuff like the tach and gearshift.
4. With all that stuff done, what's a realistic race weight for one of these cars? The interior would otherwise be intact, but there'd be lightweight race seats, steering wheel, battery. No roll bar or anything as this'll be for autocross only. Is 2400 out of the question? Does the car fuel starve in sweepers when low on fuel?
5. I know these cars weren't meant for drag racing but some of our events feature drag-race starts. How reliable is the stock G50 trans and its halfshafts in this situation, with the power and weight as described above? The 255 street tires would be 140-treadwear "street tires", though the perfomance level of the really high-end 140 tires is approaching the grip levels of R-compounds from not that long ago.
Sorry for my first post here being so question-filled. I promise I've done quite a bit of searching to get this far in research. Greatly appreciate any input you can provide.
--Jason Rhoades
Hello,
The SCCA is putting together a new autcross class called STR. The 80's era 3.2 is the only 911 allowed in the class, along with the Honda S2000, Mazda MX5, Nissan 350Z, and Toyota MR2 Spyder.
I think a 911 would be a really fun car to put together for the class. I've been researching the cars a bit but there is some stuff that you can't get from the spec sheets. Would appreciate any input the community could provide.
Here goes-
1. Engine mods allowed are a cold air intake, headers (must retain cats, but they can be high-flow), cat-back exhaust, pulleys, and ECU tune. Everything else stock. Does 190-200ft-lbs. between 5000 and 6000 rpm as a peak torque range, to the wheels, sound about right? The '88-'89 G50-trans cars all had 3.444 final drive with 2.059 2nd gear right?
2. We're allowed wheels up to 9" wide and tires up to 255 in width. We can roll fender lips and have freedom over ride height and alignment, but can't flare. I don't think fitting the max allowed in the rear will be a problem, but what about the front? Maybe it won't "need" as much in the front but it would be good to know what can be done. This'll be a race car/toy so some rubbing is ok, and it won't need full steering lock. Assume this is a regular narrow-body car, not one with the widebody option.
3. The Club Sport is allowed in. I know finding a real one is basically impossible and turning one into a racecar would be heresy, but we are sort of allowed to do pseudo-conversions in some cases. Are the 911CS engines really any different than the standard 88-89 engines, other than ECU? If you took a regular '88 coupe, removed the AC, sound deadening, rear seat, welded up the sunroof panel (or can you get one without sunroof here?), and swapped in manual windows and locks (and headliner I guess), what big stuff would still be different from a Club Sport? I know there was little stuff like the tach and gearshift.
4. With all that stuff done, what's a realistic race weight for one of these cars? The interior would otherwise be intact, but there'd be lightweight race seats, steering wheel, battery. No roll bar or anything as this'll be for autocross only. Is 2400 out of the question? Does the car fuel starve in sweepers when low on fuel?
5. I know these cars weren't meant for drag racing but some of our events feature drag-race starts. How reliable is the stock G50 trans and its halfshafts in this situation, with the power and weight as described above? The 255 street tires would be 140-treadwear "street tires", though the perfomance level of the really high-end 140 tires is approaching the grip levels of R-compounds from not that long ago.
Sorry for my first post here being so question-filled. I promise I've done quite a bit of searching to get this far in research. Greatly appreciate any input you can provide.
--Jason Rhoades
07-24-2009, 10:26 PM
#2
5) 911 Transmissions and drivelines don't respond well to abuse. And they aren't cheap to find used or rebuild out of pocket. In a word, drag racing a 911 is an exspensive proposition.
2) Wheels - 9's fit in the rear. 7.5-8.0 fit up front. Widest tires I've seen are 245 front, 275 rear, just for comparison. Any restriction on diameter?
3/4) Non sunroof coupes were available in the US, but are hard to find. Are ROW (euro market) cars allowed or only US models? you could get close to 2400#. Yes, a 911 low on fuel will have pick up problems. Need at least 1/4 tank (its a 22 gallon tank iirc) to prevent starving.
1) A "wong" chip is reportedly good for 240 hp from what I've heard over the years. the US 3.2s were rated from 200-217 depending on year. Freeing up exhaust and a chip could get you another 20hp on top of those numbers.
Why only the 1980s 911 (ie, why not also the SC's?)
2) Wheels - 9's fit in the rear. 7.5-8.0 fit up front. Widest tires I've seen are 245 front, 275 rear, just for comparison. Any restriction on diameter?
3/4) Non sunroof coupes were available in the US, but are hard to find. Are ROW (euro market) cars allowed or only US models? you could get close to 2400#. Yes, a 911 low on fuel will have pick up problems. Need at least 1/4 tank (its a 22 gallon tank iirc) to prevent starving.
1) A "wong" chip is reportedly good for 240 hp from what I've heard over the years. the US 3.2s were rated from 200-217 depending on year. Freeing up exhaust and a chip could get you another 20hp on top of those numbers.
Why only the 1980s 911 (ie, why not also the SC's?)
07-24-2009, 11:11 PM
#3
Drifting
http://www.scca.com/newsarticle.aspx?hub=3&news=3629
TOPEKA, Kan. (My 7, 2009) – Sports Car Club of America’s Solo Events Board has approved a new supplemental class—Street Touring® R (Roadster), for competition in 2010.
The approval comes after considerable member support to expand the ST category to include a class for modern roadsters. While many cars are eligible, member feedback helped establish the Honda S2000 and Mazda Miata as the class’ performance targets. Allowances will be tailored for eligible vehicles to establish performance parity.
The class will have the following requirements and restrictions:
- Two seat sports cars
- Engine displacements up to 2.8-liters
- No forced induction
Eligible vehicles will include, but is not limited to:
- All STS eligible vehicles per the requirements and restrictions, plus
- Honda S2000
- Mazda Miata
- Mazda MX-5 Miata
- Toyota MR2
- Toyota MR2 – Spyder
- BMW Z3 (non M)
- BMW Z4 (non M)
- Mazda RX-7 (non-turbo)
- Porsche Boxster
- Porsche 968
- Porsche 944 (non-turbo)
- Pontiac Solstice
- Saturn Sky
Excluded vehicles due to performance potential:
- Lotus cars
Additional class notes include:
- Tire Allowances:
o AWD – 225mm
o 2WD – 245mm
- Wheel Allowances:
o AWD – 7.5”
o 2WD – 8.5”
- Catalytic Converters:
o Same as ST, STS allowance.
- Limited Slip Differentials:
o STR: Only standard LSDs allowed OR Allowance same as STX, STU
The class will run with supplemental status in 2010, meaning that no National Champion will be crowned. Should the class show considerable interest, and meet participation requirements, it may be approved for full National status in future years.
The SEB is seeking input on the following items. Members should send any input on these items to seb@scca.com.
1. OE LSD vs. Aftermarket LSD: All of the target vehicles are available with Limited Slip Differentials (or electronic equivalents) as standard equipment in some optional configuration. Restricting all cars to OE limited slips would reduce costs. That said, not all factory LSDs are equal and an argument can be made that, for reasons of parity, aftermarket parts should be allowed.
2. Inclusion of 2006-present Mazda MX-5: Is this car appropriate given the desired performance level of the class?
TOPEKA, Kan. (My 7, 2009) – Sports Car Club of America’s Solo Events Board has approved a new supplemental class—Street Touring® R (Roadster), for competition in 2010.
The approval comes after considerable member support to expand the ST category to include a class for modern roadsters. While many cars are eligible, member feedback helped establish the Honda S2000 and Mazda Miata as the class’ performance targets. Allowances will be tailored for eligible vehicles to establish performance parity.
The class will have the following requirements and restrictions:
- Two seat sports cars
- Engine displacements up to 2.8-liters
- No forced induction
Eligible vehicles will include, but is not limited to:
- All STS eligible vehicles per the requirements and restrictions, plus
- Honda S2000
- Mazda Miata
- Mazda MX-5 Miata
- Toyota MR2
- Toyota MR2 – Spyder
- BMW Z3 (non M)
- BMW Z4 (non M)
- Mazda RX-7 (non-turbo)
- Porsche Boxster
- Porsche 968
- Porsche 944 (non-turbo)
- Pontiac Solstice
- Saturn Sky
Excluded vehicles due to performance potential:
- Lotus cars
Additional class notes include:
- Tire Allowances:
o AWD – 225mm
o 2WD – 245mm
- Wheel Allowances:
o AWD – 7.5”
o 2WD – 8.5”
- Catalytic Converters:
o Same as ST, STS allowance.
- Limited Slip Differentials:
o STR: Only standard LSDs allowed OR Allowance same as STX, STU
The class will run with supplemental status in 2010, meaning that no National Champion will be crowned. Should the class show considerable interest, and meet participation requirements, it may be approved for full National status in future years.
The SEB is seeking input on the following items. Members should send any input on these items to seb@scca.com.
1. OE LSD vs. Aftermarket LSD: All of the target vehicles are available with Limited Slip Differentials (or electronic equivalents) as standard equipment in some optional configuration. Restricting all cars to OE limited slips would reduce costs. That said, not all factory LSDs are equal and an argument can be made that, for reasons of parity, aftermarket parts should be allowed.
2. Inclusion of 2006-present Mazda MX-5: Is this car appropriate given the desired performance level of the class?
07-24-2009, 11:40 PM
#4
Rennlist Member
Listing the Boxster non-S as fitting suggests that they think the Boxster S would be too quick for this group.
I don't see the 911 3.2-liter listed, but maybe it was added recently. I used to AX an '88 911 3.2 in AS (now in BS), but S2000s are winning AS now.
I don't see the 911 3.2-liter listed, but maybe it was added recently. I used to AX an '88 911 3.2 in AS (now in BS), but S2000s are winning AS now.
07-25-2009, 01:56 AM
#5
Addict
Rennlist Member
Rennlist Member
Here is the revised Proposal for the STR, as published in the August Fastrack.
It was noted on another forum by a long time SCCA member and autox'er that the boxster was specifically excluded because they felt it would dominate and classes in SCCA don't tend to survive when a Porsche is the "car to have".
*******************************************************
Per the STAC, the following revised version of the STR proposal is published for member comment (significant changes are
shown in italics):
“Street Touring Class R (STR)
Class requirements and restrictions:
- Only those cars listed below are eligible
Eligible vehicles are:
- Honda S2000
- Mazda Miata (except Mazdaspeed)
- Mazda MX5 Miata (’06-‘09)
- Toyota MR2 (non S/C, non-turbo)
- Toyota MR2 Spyder
- BMW Z3 (non-M)
- BMW Z4 (non-M, non-turbo)
- BMW M Coupe & M Roadster (1998 to 2000)
- Mazda RX7 (non-turbo)
- Porsche 924 & 944 (non-turbo)
- Porsche 911 (1984 to 1989 Carrera 3.2)
- Porsche 968
- Pontiac Solstice (non-turbo)
- Saturn Sky (non-turbo)
- Datsun 240Z & 260Z & 280Z & 280ZX (non-turbo)
- Nissan 350Z
Additional class notes include:
- Tire Allowances (add to 14.3):
AWD – 225mm
2WD – 255mm
- Wheel Allowances (add to 14.4):
AWD – 7.5”
2WD – 9”
- Catalytic Converters (add to 14.10.E):
Same as ST, STS allowance.
- Limited Slip Differentials (add to 14.10.K):
Aftermarkets units allowed per STX/STU rules.”
NOTE, per the STAC: Classing for STR will not be formula based, but will utilize a list of eligible vehicles. Cars *not* on this list
are not eligible. However, as in all subjective classing, cars may be petitioned by the membership for inclusion and will be
reviewed on a case by case basis.
********************************************************
It was noted on another forum by a long time SCCA member and autox'er that the boxster was specifically excluded because they felt it would dominate and classes in SCCA don't tend to survive when a Porsche is the "car to have".
*******************************************************
Per the STAC, the following revised version of the STR proposal is published for member comment (significant changes are
shown in italics):
“Street Touring Class R (STR)
Class requirements and restrictions:
- Only those cars listed below are eligible
Eligible vehicles are:
- Honda S2000
- Mazda Miata (except Mazdaspeed)
- Mazda MX5 Miata (’06-‘09)
- Toyota MR2 (non S/C, non-turbo)
- Toyota MR2 Spyder
- BMW Z3 (non-M)
- BMW Z4 (non-M, non-turbo)
- BMW M Coupe & M Roadster (1998 to 2000)
- Mazda RX7 (non-turbo)
- Porsche 924 & 944 (non-turbo)
- Porsche 911 (1984 to 1989 Carrera 3.2)
- Porsche 968
- Pontiac Solstice (non-turbo)
- Saturn Sky (non-turbo)
- Datsun 240Z & 260Z & 280Z & 280ZX (non-turbo)
- Nissan 350Z
Additional class notes include:
- Tire Allowances (add to 14.3):
AWD – 225mm
2WD – 255mm
- Wheel Allowances (add to 14.4):
AWD – 7.5”
2WD – 9”
- Catalytic Converters (add to 14.10.E):
Same as ST, STS allowance.
- Limited Slip Differentials (add to 14.10.K):
Aftermarkets units allowed per STX/STU rules.”
NOTE, per the STAC: Classing for STR will not be formula based, but will utilize a list of eligible vehicles. Cars *not* on this list
are not eligible. However, as in all subjective classing, cars may be petitioned by the membership for inclusion and will be
reviewed on a case by case basis.
********************************************************
07-25-2009, 02:43 AM
#6
Track Day
Thread Starter
Join Date: Oct 2006
Posts: 24
Likes: 0
Received 0 Likes
on
0 Posts
Yep, I agree with Mike, they felt the Boxster/Cayman (S variants especially) would be too fast for the class, overdogs. The 911 SC's were likely omitted not because they'd be overdogs, but because not too many people would be likely to run them, and the Carrera is probably the faster car under the ruleset.
Racer, thanks for the reply. Cars have to be US versions, nothing international. Diameter is free - was thinking I'd probably end up with 17" wheels unless there was some sort of big clearance advantage with 18's. The good tires (Yokohama Advan Neova AD08, Bridgestone RE11, etc.) come in good 17" and 18" sizes, but not much in 16" and smaller.
Interesting about the existence of non-sunroof coupes, will have to look to find one when that time comes.
Racer, thanks for the reply. Cars have to be US versions, nothing international. Diameter is free - was thinking I'd probably end up with 17" wheels unless there was some sort of big clearance advantage with 18's. The good tires (Yokohama Advan Neova AD08, Bridgestone RE11, etc.) come in good 17" and 18" sizes, but not much in 16" and smaller.
Interesting about the existence of non-sunroof coupes, will have to look to find one when that time comes.
07-25-2009, 04:25 PM
#7
Drifting
FYI, displacement is limited to 2.8L. 3.2L is apparently not allowed.
I'm really surprise they left the S2000 in there, as S2000s seem to consistently best Boxsters at nationals, and just seem way overpowered compared to the rest of the class. Whether that's due to the cars simply being fast, or just no fast Boxster drivers entering is an issue for debate, though.
I'm really surprise they left the S2000 in there, as S2000s seem to consistently best Boxsters at nationals, and just seem way overpowered compared to the rest of the class. Whether that's due to the cars simply being fast, or just no fast Boxster drivers entering is an issue for debate, though.
Trending Topics
07-25-2009, 06:03 PM
#8
Addict
Rennlist Member
Rennlist Member
The displacement limit has been removed in the latest proposal. Hence the 3.0L 968, 3.2L 911, and 3.5L 350z all allowed.
I will agree with you about the Boxster, its exclusion doesn't seem justifed. It has but two Solo National Championships (1 open, 1 ladies in 2001) and two Pro Finale wins since production began in 1997. None in the last 5 years. The S2k has more than double the number of National Championships and more to come now probably with the CR model. Older Boxsters are dirt cheap, much less than a lot of cars on that list.
07-25-2009, 08:35 PM
#9
Track Day
Thread Starter
Join Date: Oct 2006
Posts: 24
Likes: 0
Received 0 Likes
on
0 Posts
Keep in mind there are a lot of mods allowed in this class, which would allow the Boxster to get the negative camber in front it can't in Stock. Also, the class is limited to somewhat narrow street tires (255) vs. wide R-comps of Stock. The mid-engined Boxster be better able to cope with the street tires when putting powier down, vs. the front engined S2000.
07-26-2009, 09:09 AM
#10
Drifting
The S2000 is technically mid-engine, too, with the engine mounted between the axles. It has 50/50 weight distribution as well.
I would LOVE to get some more camber. Would suck to finally be allowed to roll fenders, but still be stuck with 255 tires...
I would LOVE to get some more camber. Would suck to finally be allowed to roll fenders, but still be stuck with 255 tires...
07-26-2009, 02:19 PM
#11
Having said that, I actually don't think the Boxster would be a threat to the S2000 (or, more importantly, the various generations of Miatas) because of its weight. The mid-engined argument is also a bit incongruous given that the MR2 Spyder's in the proposal.
07-27-2009, 03:20 PM
#12
Track Day
Thread Starter
Join Date: Oct 2006
Posts: 24
Likes: 0
Received 0 Likes
on
0 Posts
Yep, I'll take 43/57 over 50/50 any day in an autocross, or just about anywhere really.
The Spyder's mid-engineness isn't as big of a deal being that its output is so low. The Boxster, while heavier, has *some* power at least. I think the earlier cars might be an OK fit but the STAC might have a hard time drawing a line where amongst the years to allow/disallow. They sure didn't want a P-car as the perceived car to have.
I like having a car that can win ProSolos, which maybe the 911 can. Having a hard time figuring out how much one would weigh in ST trim, and what the deal is with the Club Sport options, if you could build a clone in ST without spending megabucks. Also looks like headers and exhaust are going to be a challenge with the cat restrictions.
The Spyder's mid-engineness isn't as big of a deal being that its output is so low. The Boxster, while heavier, has *some* power at least. I think the earlier cars might be an OK fit but the STAC might have a hard time drawing a line where amongst the years to allow/disallow. They sure didn't want a P-car as the perceived car to have.
I like having a car that can win ProSolos, which maybe the 911 can. Having a hard time figuring out how much one would weigh in ST trim, and what the deal is with the Club Sport options, if you could build a clone in ST without spending megabucks. Also looks like headers and exhaust are going to be a challenge with the cat restrictions.
07-28-2009, 09:23 AM
#13
Burning Brakes
I race a 996TT and an 04 S2K and used to race a 992 C2 at SCCA events, a well setup S2k With the right tires will dominate that class, a 3.2 IMO has no chance (given both cars have equally skilled drivers)
