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Calling All Suspension Experts

I have a 1987 3.2L Carrera. I use it for street commuting exclusively. However, I can see myself doing maybe one or two Autocross's in the future. I just completed a total suspension rebuild using quality Elephant Racing components. I would like to know if any Pelicans have any comments on the car/suspension setup; suggested additions and what that addition will add to the car. Also, I would like to have any negative feedback as well. My car seem to drive great. A big improvement from stock. The ride quality is great and quite comfortable. I have not noticed any bottoming out. However, the front spoiler does hit alot of driveways. My biggest problem is tire flex. When I enter a turn the suspension works well. I think the tires are the weak link.

? RSR struts for increased front suspension geometry/travel? From Bilstein Sport shocks? ?????????

My car:
1987 Carrera 3.2L narrow body with new engine.
All parts/tires are new ELEPHANT RACING (ER). Suspension install by me; Alignment and Corner balance from VISION MOTORSPORTS.

Front:
ER Rebuilt A-arms with Polybronze bearings, ER Low friction mounts, new stock oem ball joints, ER 21mm hollow torsion bars, Tarret adjustable sway bar with back date mounting, Tarret adjustable camber plates, ER 935 replica strut brace. Bilstein HD's, ER adjustable bump steer kit.
7X16 Fuchs with ride height: 24.5" from ground to top of fender.
Tires: Continental Contact2 225/45-16 (35 PSI)

Rear:
Sway-Away adjustable spring plates, 29mm torsion bars, Tarret adjustable sway bar, ER Polybronze, Bilstein Sports, ER Camber Max adjusters.
9X16 Fuchs with ride height of 24.5" Tires: Continental sports 245/45-16 (35 PSI)

Alignment Specs:
Front: 1.25 degree negative camber; Zero toe; 6.5 degree caster
Rear: 1.75 degree negative camber; 1/8" total toe

By the way. The suspension project was initially budgeted for $2000. After a few conversations with Chuck at Elephant Racing I slide down the proverbial "slippery slope" like a greased Hippo sliding down a steep incline made of polished glass! As 4FLYBOY once said "BURN BABY BURN"
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Last edited by mnmasotto; 09-12-2008 at 11:37 AM..
Old 09-10-2008, 09:04 PM
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That is way more suspension than you'll need for a dd/autox car honestly. I wouldn't change anything until you drive it for a while. Making more changes won't help you when you don't even know how the car will react due to the changes that you've made already. If you have the itch to change something take a look at the tire thread that people have been talking about what they run and choose some higher performing tires for street/autox duty. I like the Bridgestone RE01Rs but the Hankook RS2s are nice as well.
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Old 09-10-2008, 09:35 PM
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29 might be too stiff in R
Old 09-10-2008, 09:46 PM
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The 911 in all its variation is incredibly sensitive to rear tire sidewall flex and tire pressure.

Without getting into everything that is wrong with your setup, bump your rear tire pressure to 40PSI

This should help you a lot.
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'82 911 SC Coupe w/'92 3.6L, bulletproofed 915/62 w/GT LSD & Wevo goodness, Rennsport RSR/Bilstein Sport, SRP ARB, ER Polybronze, BK strut brace, 15x7/8" Fuchs.
Sold: 92 964 Turbo, 81 SC, 96 993 Coupe, 82 SC, 89 Carrera Cabriolete
Old 09-10-2008, 10:07 PM
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I offer one statement: There is NO such thing as too stiff.
These are sports cars, not station wagons. That being said, you have a very nice setup for the street.
Old 09-10-2008, 10:41 PM
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Have Tarrett started making a 30mm front bar?
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Old 09-10-2008, 11:32 PM
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30s would be WAY to stiff for the front ! I have 22/29s on mine and love the combination (paired with Bilstein HD/Sports). I was sent 23s by accident, and a real suspension guru advised me to return them as even 23s would have been to stiff (in his opinion). 29s on a Carrera are just fine.
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Old 09-11-2008, 04:22 AM
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Correction

I want to correct a few misunderstandings. The Tarret Sway Bars are the ones sold here at Pelican. I thought they were 30's but I may be wrong. They seem to be much thicker than my prior 23mm Weltmeister.

My Torsion Bar setup is 21mm in front and 29mm in back. The 29mm rears were not Chuck's recommendation. I had the 29mm rears before I started on this suspension project.

What about RSR struts with Bilstein Sports in the front?? I was also planning on getting aset of 17" Forged Fuchs from Jeff Alton. Will the wider range of tire choices make a big difference???
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Last edited by mnmasotto; 09-11-2008 at 06:25 AM..
Old 09-11-2008, 06:22 AM
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I don't see why you'd need RSR struts with Bilstein Sports in the front unless you intend to go to a full front coilover suspension or you need to really correct some suspension geometry that a bump steer kit can't take care of. But, it's your money so if you really want it buy it and put it on.

Wider tires always help and it seems to be a bit easier to find wider tires when they are made for the 17" rims.

Like I said before, I wouldn't worry about getting anything else until you've driven the car a while and determined what you do and don't like about it. Does the backend seem too twitchy? Do you have too much understeer/oversteer? Does it ride too rough? Are you getting bump steer?

Then see what you can modify on your setup already such as tire pressures as someone already mentioned. With the sway bars you can easily dial in/out oversteer and understeer and you should have sufficient camber to handle any street tire you are going to want to run. Then if you can't dial out or remove the attribute you don't like, figure out what your choices are to remove that attribute you don't like.
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Old 09-11-2008, 06:51 AM
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Update

I have been putting alot of miles on the car. I seem to have alot of understeer. The ride is fantastic! But I tend to prefer a stiff ride.
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Old 09-11-2008, 07:02 AM
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I have a similar setup to yours except I'm using a Wevo Camber King instead of the strut tower hardware you have and 22s up front. My alignment is close to your except for .5 more camber up front. I use the car for street /autox. The biggest difference is there is no more slop under hard cornering. The car seems to carry more more momentum through a corner now.I don't think the 29s are too stiff on a G50 car. If I was to do it again, I might have went for the 30s. I might pull the shocks and struts out and have them re-valved to match the bars next year. Tires make a huge difference. Try the Bridgestone RE01s. They're soft and grippy, but I don't expect more the 10K out of them. They're also comfortable the street. I think you can still get a $100 rebate on a set of 4 if your a PCA or SCCA member.

I would see if any of your local clubs has a test and tune event. You play around with your adjustability.
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Old 09-11-2008, 07:39 AM
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You seem to be more insterested in extravagant solutions than you are interested to fix the obvious problems

1. 225 front track and 245 rear track. This is dissproportionate change in contact patch front to rear from the standard setup - of course you understeer! Your alignments needs to compensate for this; you should not be using stock alignment values.

2. 35 PSI in the reear is way too low for your setup. You need to bump it at least to 40 PSI. This will help you dramatically if you have the right rubber. If this does not help, go buy a proper set of tires (which will not be easy since you are running on-standard sizes)

3. If your front sway is 30mm and your front torsion is 21mm, this is a huge rate missmatch. If you like stiff, your front torsion rate needs to bump up to 23mm to compensate and reduce front dive. The suspension is a system, the parts needs to work together properly both as a front configuration, as a rear configuration, and as a front to rear match.
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'82 911 SC Coupe w/'92 3.6L, bulletproofed 915/62 w/GT LSD & Wevo goodness, Rennsport RSR/Bilstein Sport, SRP ARB, ER Polybronze, BK strut brace, 15x7/8" Fuchs.
Sold: 92 964 Turbo, 81 SC, 96 993 Coupe, 82 SC, 89 Carrera Cabriolete

Last edited by ToddM; 09-11-2008 at 09:12 AM..
Old 09-11-2008, 09:10 AM
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Agreed that 21mm fronts sound like a mismatch for a 29mm rear torsion bar. I'm interested to hear what solution you find, as I have the same squishy tire feeling (and I've played with tire pressure quite a bit to no avail).
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Old 09-11-2008, 09:58 AM
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Quote:
Originally Posted by rattlsnak View Post
I offer one statement: There is NO such thing as too stiff.
These are sports cars, not station wagons. That being said, you have a very nice setup for the street.
- I disagree entirely. Even on a track, one get a suspension that is too stiff.

In his case: "I use it for street commuting exclusively" and he contemplates 1 or 2 AutoX's. Currently, he does NONE. You've given him very bad advice.

Moreover, he has 21/29 which again I think might be a bit too stiff in the rear -- i.e. for a 21 in front.
Old 09-11-2008, 10:10 AM
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Quote:
Originally Posted by gtc View Post
Agreed that 21mm fronts sound like a mismatch for a 29mm rear torsion bar. I'm interested to hear what solution you find, as I have the same squishy tire feeling (and I've played with tire pressure quite a bit to no avail).
Sometimes a particular tire just wont work at all no matter how much you play with the tire pressure due to poore rear sidewall support structure internal to the tire. RE050 comes to mind as something that just doesnt work.
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'82 911 SC Coupe w/'92 3.6L, bulletproofed 915/62 w/GT LSD & Wevo goodness, Rennsport RSR/Bilstein Sport, SRP ARB, ER Polybronze, BK strut brace, 15x7/8" Fuchs.
Sold: 92 964 Turbo, 81 SC, 96 993 Coupe, 82 SC, 89 Carrera Cabriolete
Old 09-11-2008, 10:16 AM
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Do you mean squishy tires in a turn only or over bumps and in turns?

If it is only in a turn, it cloud be because of the suspension geometry. The semi-trailing arm suspension design has a much lower roll center than the MacPherson struts configuration. On a 911, this means the front has much more inherent roll stiffness than the rear does. This is why early 911s lift their front inside wheel so much.

You may need to compensate for this with a larger rear anti-sway bar. The rear anti-bar to torsion bar stiffness ratio would be larger than the front in order to make the car stay flatter and not wallow. This will also make the car rotate quicker (good for auto-x).

Walloeing can also mean you are underdamped. If you put in stiffer torsion bars without re-valving the dampers to match, the car will bounce around over bumps.
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Old 09-11-2008, 10:17 AM
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Quote:
Originally Posted by RWebb View Post
- I disagree entirely. Even on a track, one get a suspension that is too stiff.

In his case: "I use it for street commuting exclusively" and he contemplates 1 or 2 AutoX's. Currently, he does NONE. You've given him very bad advice.

Moreover, he has 21/29 which again I think might be a bit too stiff in the rear -- i.e. for a 21 in front.
I did say he has a nice setup for the agressive STREET, but I agree with the mismatch, but he needs stiffer bars in the front, not weaker ones in the rear. . He already had the 29s in the rear he says and has has done all of the bushings, bars and joints, which point to agressive DEs and AX, not street, regardless of what he is actually doing, so it looks like he WANTS the stiff car.
>>from him: The ride is fantastic! But I tend to prefer a stiff ride.<<<
Old 09-11-2008, 01:15 PM
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Ok - let's agree that he keep his torsion bars not sell them.

Then he either buys a stiffer front and tries that first.

Or if too stiff for him on 99% street or whatever, he buys a smaller rear and tries that....

THEN, he sells off the ones he does not want.

This is why people get rides with others... but (as is the case with speakers that are too bright) it often takes a while to "not like" stiff t-bars. At first, everything is wonderful, you're carving around like a madman. Then - maybe weeks later - ow! my kidneys are being beat to death, AND I am actually slower on the street than a more compliant car.

Some tracks - like the back stretch on PIR - also can teach the meaning of too stiff. Some cars have gone airborne over that bump.
Old 09-11-2008, 01:25 PM
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Update

I increased the tire pressure to 40 PSI. Big difference in the way the car feels. The under steer is almost gone.

As far as the possible mismatch on the TB's go - I had the 29mm rear TB before I started the suspension project. Chuck had some initial reservations about going with 21mm in front. However, I was very concerned about the ride being too stiff. So I opted for the 21mm fronts. Turns out, I probably would have been happier with the ride quality of the 22mm TB's. I really enjoy the stiffer ride.

I seem to have a very annoying noise coming from the front suspension. After many hours and $1300 labor costs, trying to isolate the noise and remedy the problem I figured out that it is coming from the TB's hitting the inside of the control arms. I covered the contact points with electrical tape and the noise was gone. So I am trying to figure out a way to correct this problem. Chuck at Elephant Racing has been a tremendous help. I have called him at least 25 times on the phone. This guy knows his stuff! He is very methodical and patient. So far, I am at the point of going with RSR front struts to eliminate the TB's completely. Any helpful prior experience would be helpful.

By the way. All the parts in the project were from Elephant Racing except the adjustable Sway-a-way spring plates. What a big difference in quality of the two manufactures! The ER components are aircraft/satellite quality and really make the Sway-a-way look sorry!
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Old 09-12-2008, 08:32 AM
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If it was me, I would have decreased the front tyre pressure rather than increase the rear to acheive the same balance change while keeping a larger contact patch. Seriously, who runs 40psi?

I would talk some more to Chuck rather than listen to some of the questinable advice being given here - ther is nothing wrong with the components you have now.
Old 09-12-2008, 08:58 AM
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