Building a Street/Track car, think more track than street. The car is flared with 16x7's and 16x8's. Building a 2.4 6 with 2.2S p/c's and 911 front suspension. I need some advice on front torsion bar size, rear springs, inserts/shocks, and sway bar size. Thanks.

And what do you guys think about these?

There are a buch of "stages" I went through.

Stock T bars & 140lb rear springs thru 21mm T bars with 300lb rear springs & lightening the car from around 2200 to 1700 lbs....it took years.

Through it all Bilstein shocks (the cat's ass IMO)....revalving upgrade in their later life.

The trick is setting the front to rear spring rates balanced to one another, throwing in a front AR bar to the mix so it can be adjusted either softer or stiffer ....I started with a 19 mm and ended up with a 22mm (effective....hollow 25mm) Tarett AR bar.

How far do you want to go?

BTW, I like the Rebel bushings but have never used them. I did needle bearings.

The very first thing to decide is whether you are going to run an LSD because that will have the biggest influence on your set up. Otherwise, what JP says. I'm running 23mm front, 300lbs rear, 20mm front bar and 16mm rear bar, yellow Koni adjustables but with a ZF.

If you are not going to run an LSD, then you would have to run softer in the rear, probably down about 225lbs and maybe no rear bar. The downside is that it would tend to understeer a bit on turn in and pick up an inside front on exit, but with that much rubber it wouldn't be too bad.

Cheers,

Good balanced -well driven cars- are always fast-Fortunately this can be achieved with our cars with a small budget or It can be upgraded to an incredible level.We have a large amount of proven performance parts available.It seems that most of this forum is busy justitfying there paticular level of setup.How hard and at what level do you plan to compete?JJackson

Thanks for the input guys.

I want to go as far as I can and still be streetable.

I plan on installing a torque sensing or LSD in my 901. Haven't decided which one yet. From what I hear the torque sensing is better suited for AX. Is this true?

So if I go with 300# rear springs I'm looking at 21 to 23 T bars and 22 to 20 sway bar up front.

JP are you running a rear bar like Downunderman?

What type of valving you running on your shocks?

The TB diff is the way to go for AX, IMO. The clutch type has the tendency to cause our light frontends (and most other cars) to push......a no no at AX. I ran no rear AR bar as I was running a TB diff. They don't work with one rear wheel off the ground......but ask Randal how his new TB diff worked. That is not to say that this could not be overcome but I never tried one. I've long since lost the valving specs off the shocks......but the rebound is very soft....no pumpng down here. Call Bilstein West & ask them what they recommend.....the cost was 65 bucks per shock + any parts needed.

As it was set up, the suspension was streetable....but not for long distance stuff.
The suspension was compliant ......due to the shock valving & needle bearings, me thinks. The AX venue whare we spent the majority of our time is rough as about any road you would come across. The 300 lb rear springs were an experiment.....275s were the final choice as they kept both rear wheels planted( pre TBD days)....250s didn't.

Tried calling Clint from Rebel Racing and his machine is full.

Any other suggestions on places to call to talk about matched shocks and springs?

Bilstein -Budget(Reasonable budget-Nice upgrade)VALVED
Ground Control-Next Step (Koni bodies)
Smart Racing -Next upgrade (Fox)
JRZ-Fordahl
Motons-?

Personally don't recommend yellow Koni adjustables-Shock dyno shows poor quality entry level shock-Ran for years-revalved several times

This is just my opinion.Last time I talked shocks and springs-decided it was better to just shut up.JJackson

Alright, bought a boat load of stuff from PMB and Rebel Racing. I went with Bilstein Sports and 225# rear springs. I need to get some 22 mm TBs up front. I also went with the Rebel front bushings pictured in my first post. IMHO bushings are better suited for the application. Clint says they have a similar rear kit coming out in a month or so. I'll wait for that for the rears.

What's a good cheap source for 911 TBs?

Don't know of cheap source other than used.Shopping will be easy.Sounds like you're getting ready to have some fun!!! Congrats on the performance upgrades-Now your challenge willl be to get it all balanced and working properly.Seat time and adjustments are comin. Good Luck. JJackson

I agree with your shock ratings. If I had held onto my 914 longer it would have had JRZ's. Its the one place where I think too many 914 guys cut corners. I have JRz's on my Z and they are the best shock I have driven on period. FYI Moton was bought by AST.

Curious what kind of LSD do you use in your car?

Guard TB.Went with JRZ's because of the testing Fordahl had done on the Gullick 3 ways.Had him valve them. (or tell JRZ the combo) ,either way, check went to Greg.JJackson

In round numbers what does a set of set up JRZ's run?

Around $6 to $7k the last timeI talked to Greg. May be a little more now.

I can think of several ways to spend that kind of money on items that I think will decrease lap times more effectively.....none of which have an equal bling factor, but there it is......that would seem to be true for every car I see represented on this forum.

If you need that last tenth to win your class at the Nats they may be worth it.

There are many mods you can do at different price points. Once you do all of the inexpensive ones sometime you have to start on the very expensive ones that don't gain much. I would guess in the National picture that once you get to that level every little advantage helps.

Just spend some time at National event with large number of top notch competitors. Speak with top racing teams who model suspensions and see what their data says. Spend some time actually testing and seeing difference between a standard koni or Bilstein tube and a well built cansiter shock. The difference in handling is remarkable. On track I was able to tune issues out of the car very easy with JRZ's. Even at AX when we had issues we completely changed handling of the car. Good 3 way adjustable shocks are awesome for multipurpose car. I would argue a 914 is even in more need of a good damper than most modern cars as you are dealing with non abs braking systems, less than ideal suspension geometry, etc. When JP's car was beaten by stock Miatas at National tour event I can assure you those Miatas had better shocks than his car. Not a bunch of "mods". Almost every top car in Street Prepared, Prepared and Modified use top notch 3 way adjustable shocks with cans. Remember JP is the guy that used to tell us that his 200 HP motor was too powerful for his race slick clad E mod 914 and that he couldnt keep power to the ground. ...hmmmm Now the car has 350 HP? double hmmmm.

If you are interested in being fastest in a given class high quality triple adjustable shocks are best bang for the buck investment. in my opinion If you are like JP and some others and just want to beat street cars in a fast modified 914 on race tires then I would agree good set of shocks is a waste of money.

I'm curious. Now that AST has bought Moton I hear that they will keep Moton as premium offering and offer AST as more mid range damper. The race team I work with on my Z uses AST 3 way adjustables on Grand Am cars as part of sponsorship and contingency package and while they arent quite as nice as the JRz's they are very capable shock. Wonder if they make a application for the 914?

http://www.ast-usa.com/ast-usa-shock-absor...roduct-list.php

There is no question that an adjustable shock is needed. It is all about dollar vs time benefit. When planning you have to put an order of what will shave time most, driver aside. Going with a single stage matched to my bars and springs is a hard step as I have seen the advantages of having even the lowly Koni adjustables at different venues or weather conditions. If only I could stumble across some JRZs for very little

That said, I am going with revalved Bils to match my weight, and spring for now.

At your last Tour event you finished what?.....6-7 sec back from your class winner?
Blather on dude.

Easy fellas.... We'll zip'em down and show'em later. Right now help me get this figured out.

I've got $3 to 4K to get this thing on it's wheels and $2,400 is burnt up already. JRZ's are out of the question. I still need a front AS bar, trailing arm bushings and rear brakes. I'm waiting on the Rebel rear bushings so that's off the table for another month. I'm debating whether or not to go with the 914/6 or 911 calipers. The 6 will calipers blow my budget. I have front A calipers. Heavy as hell but what I have to work with at the moment. I'll upgrade to the S caliper later. In the meantime what would you guys recommend? Go with the 6 or 911?

So in round numbers:

Koni's - less than $800 dollars
Bilstein -With revalving guessing about $1200
Smart Racing -Rich Walton told me about $2,500 for a complete set.
Ground Control-The Beast ground control shocks cost $1000 a corner or about $4,000.
JRZ-Fordahl - About $7,000
Motons- no clue

Does this sound about right?

911 M rear calipers are a good match for the A fronts. Tarett makes a good anti roll bar. I *think* Chuck Morland (Elephant Racing) sells bronze rear bushings for the 914.
Edit: Ayup, he does. $315 for the kit thru Pelican.

I would talk with Performance Shock. He offered me a real deal on Penske dampers for my 914 a few years ago. Still kicking myself for not going for those.

Not all shock costs are same either. My JRZ clubsports were cheap but then I got them at cost through sponsorship but I shopped around for JRZs online and found $1000 difference between suppliers. I wouldn't have bought them at full retail. I would call AST as they make good shock at lower cost - curious if they might have something that would work with 914.

http://performanceshock.com/

I went with M calipers on rear of my 914.

You may want to go with a little more rear spring than 225. I settled with 250 to 275 depending on venue. And I had 19mm front torsions. The car pushed too much with anything less and that was without a LSD initially. No rear bar.

They are my second choice. Clint from Rebel said they had a kit in the works. It's similar to their fronts with the exception of a tube insert you weld (or lock with a nut) into the trailing arm. It seems like a better fix IMHO than relying on the poly to deform. I would think they might not be true to each other and bind a bit. If they don't come through I'll go with the Elephant.





I'm a bit worried about that myself. Chris recommended 200 and so did Clint. I went a bit heavier with you guys suggesting 250 to 275. If I push I'll install my rear bar. If I get wheel spin I'll go to a heavier spring.

You'll have to excuse my ignorance. Whats the difference between the M and SC rear caliper? I don't know jack about 911 rears.

rotating mass
unsprung weight
weight in general with the vented rear rotors (absolutely unnecessary)

SCs are 'M'.
The problem I had with The stock rears & S calipers(about the same as 'A's but aluminum) was that the rears weren't doing enough work.....even with the adjustable proportioning valve wide open. The new stock rotor still had the machining marks on em' after 3-4 months.....couldn't get around that.

I'd bet Chris and Clint are more on the ball than any of these guys here. Greg has said 200-225 is perfect for a 914 with no rear bar. Since Greg is an actual race engineer for a big race team and has won nationals with a 914 that gives him a lot of leverage. Chris and Clint as well have shown they know their stuff.

JP, Randall, Me, Grant, are all guys with different opinions and life experiense but nothing really to show for it. Take what we say with a grain of salt

If you can find a rear caliper that has a bigger piston without going to a vented rotor you will be better off. Eric will know what you can do.

It depends on which front T/AR bars one is using.

Blanket statements (which seems odd for Greg) like that are usless.....but if you want to go with that, be my guest.

Brit recently went to 325 lb rear springs which cured the push that popped up after the approx. 100 lb Subie weight gain..... in lieu of softening the front AR bar.

BTW:
"nothing to show for it".
With Brit driving, the Shitbox went up against every hot 914 AXer on the West Coast (with the exception of Provasi, darn it) in the last 3-4 years. At worst, he broke even.

Remeber setup for AX car is a lot differnt from track. The reccomendations from the very capable track guys are spot on for track work. As much as I'd hate to admit it JP does know a bit about AX setup. So does Randal. But you are right non of us have ever accomplished sqwat with 914 at a national level. I can live with that. But I suspect JP will continue to delude himself into thinking he built the worlds finest 914 ax ever known to man. Curious have Greg, Clint or Chris set up a nationals winning 914 AX car? If they have I guess I missed that in the past several years. LOL!

But ultimately it all comes down to expereimenting. There is no single right answer. Driving technique, tire choice, etc all play into setup. I would budget money for a few differnt spring combos from 225 to 275. That should do it.

Greg has and has won in that 914 at Nationals a few times. Which is why when I hear JP or you contradict stuff I have heard from Greg I always question it.

Yes, track is different, but how the car handles is going to have similar traits.

Clint sells this stuff all day to people like Greg so he has an idea what they are using. So that coupled with his engineering makes him a decent sounding board. I would say the same goes for Chris. The rest of us are doing our best. It would be nice if you guys didn't bicker so much and just shared your successes. I am sure many more would learn from it rather than just be turned off by what you say.

JP, let me ask this honestly, is this because of your hard work and skill or Britains?

From the people I have heard from your car wasn't much of anything until Britain came along. I may have heard wrong but that IS what I heard.

My $ .02. In the January Pano, Mr. Mayo answers a tech question about swaybar set-up for a beginning auto-crosser; "I came up with a set-up 20 years ago that I've used on my car and many customer cars.Everyone has liked it, as it seems to be competitive, yet very streetable. I use 150 pounds springs on adjustable-perch gas Koni's, 21mm torsion bars with adjustable gas Koni's, a 19mm adjustable front sway bar adn no rear bar. I remove the front shock tower protective tubes (you have to cut the spot welds and remove the washer end off of the top of the tube and install it, as it is what prevents the shock from going through the rubber strut mount). Cut off the two softer sections of the rubber bump stop, set the front ride height so that you have an inch and a half of travel before the shock hits the bump stop. Set the rear height so the car sits level. Properly corner weight it, set the rear camber for -2 1/2 degrees the front for all you can get, usually about -1 3/4. Set the rear to have +1/16 inch toe in per wheel, and the front for -1/16th inch toe out per wheel......." This may not help you because it sounds like you may be beyond this set-up, but it may help some other small-frye, like it did for me. Let us know how it goes! Dave

I'm always honest....honest enough to admit I'm not God's gift to driving.

It was quick with a quick driver .....that would not be me....I started AXing too late, me thinks....too old & set in my ways to be fast. The car got quicker but needed a good driver....that is where Brit came in...kinda like your co-driver Matt.

He was driving his 1.7L 914 at PCA events, I let him drive the car one day and decided he had some talent for it (less all the cones. ) He beat my time (as did about everyone else that got a chance to drive it)....he got the co-drive. He stepped up nicely and will continue to do so, IMO.

Quite a bit of development has come along since Brit got the ride and he was very helpful. After he bought the car, he started setting priorities & I'm "helpful".

BTW, would you like to hear what folks say about you? I'm really not interested in what "they" say as I depend on my own judgement when meeting people......you might want to try that.

Just keep in mind AX isn't my gig. I prefer large tracks and W2W competition. We'll see if 225 works. If not, springs are cheap.

JP,

not arguing
but now I'm curious
I get a ton of rear brake wear/heat
never enough to want to go back to my old cars vented rear rotors... never a problem.

but I'm wearing through rear brake pads 2 to 1 over the front
same compound front and rear

fronts are vented with S calipers (knock backs gutted)
rears are 914 front early calipers moved to the back (same pad as a M caliper)

I think the 914/4 front may have a tiny bit smaller piston than a true 911 front M caliper (even though the pad size is the same)

maybe its the 1-2mm smaller piston?

I've fabricated all new rear brake lines, but I think they were of stock diameter.

I'm running an adjustable proportioning valve (that I dare not open all of the way)

our engine weights were similar, although your car weight may have been a bit less than mine.

still I would say similiar chassis.... yet I'm buring through 2 sets of rear pads to ever front and getting tons of rear brake.

maybe heat?... maybe pad compound that is working in the heat I'm getting? I dunno... but I have AMPLE rear brakes and have to dial them off a bit

I change my brake proportioning bias about once a weekend to accomodate warm, cold, or wet track

now I'm curious

I'm no expert ( no real racin' here) but have an opinion.
I think you've nailed it with the word "heat".
It is not for nothing that vented rotors are the choice for racers. Heat is a killer.
It is not just the venting but also the size of the "heat sink". If you don't want to go vented rears you should start looking for some ducting to cool the rears......tho I doubt they would work very well with solid rotors. You could also use more heat resistant pad in back....an iffy proposition till everything gets up to temp.
Personally, I'd go to vented rotors, eat the weight penalty, & be done with it.

Actually I'm not having any problems with it, No need to change to the heavy vented rear rotors
- I have all of the rear brake I can use in balance with my front S calipers
- my pad life is still about 10 full track days, so pad life is not a concern for me
- I never over heat the rear brakes.... (or fronts for that matter)

the only reason I brought it up was that Ive heard multiple people claim they don't have enough rear brake even with the proportioning valve fully open...
yet I have plenty... I can open the valve further and lock the rears first at will
so I'm just curious what is different in the set ups to make mine well balanced?

no need to change anything on mine... I've got what I want and what others can't seam to achieve.

I used to have vented rear rotors on a different teener race car
maybe if I had another 100hp I'd feel differently (although I doubt it)
but I don't need them... can't see adding the weight back if it only makes you heavier-slower....

besides. These are momentum cars. If you are heating your brakes too much with 200hp, you are just braking too much. I've known faster guys than I in teeners that have even smaller brakes without problem... they just don't brake much and they are faster for it.

actually the fastest real racers I know don't use vented. On the race tracks (don't know autox) if you talk to some of the true 914 drivers (such as Allen Johnson in a 205hp 4-cylinder) They will run laptimes faster than the 500hp mustangs, corvette's and camaro's and do it all without big brakes. You can't run those kind of lap times if your braking much.

brant

The problem I had with the rears were with 914 *rear calipers*, not fronts used on the rear. You're right, the 914 fronts are about the same as the M 911 rears except for the width. I guess I missed the crux of your post.

Then I think you are right on track. My car worked very well with lighter rear springs on the track. Minimal understeer etc. There's a big difference between warm front tires we can get on the track and cold tires we typically see in AX. You just need a little help with cars that require rotation when tires are cold.

Here is my old car on Laguna Seca.

http://www.youtube.com/watch?v=aSaL5XpVTt8

Yep. My brakes never overheated a single session. My style was to go in hard and fast stab to scrub off a little speed and then right back on throttle and hold on for dear life and hope I wouldnt run out of track LOL!

I was really spoiled by light weight momentum car like 914 as my first track car. It was dissapointing and expensive to get in heavier cars that really did need brakes. My Nisan has huge rotors and huge calipers to keep braking undercontrol. So far so good but the brakes look like they could stop a semi. LOL!

This is because I believe you have your theory on pistons backward. (Edit: Sorry, just reread, you mention 914 front vs. 911 front. 42mm vs 48mm so... it is sizable in fluid terms.)

A 914 front caliper actually has "more" piston than a 911 rear caliper. 42mm vs. 38mm so, you have more clamping force and have to dial it out.

This is why I prefer a 911 rear caliper in your situation with the spacers removed and using the fasteners from your 914 front calipers to bolt them back together. Same pads etc.

Do that and you will have a very well balanced bias. Or, it sounds like your happy with the heavy rear bias and dialing it out.