Suspension and Brake Upgrade Time

John, this is front AND rear? if so, DAMN! i bet it stops NOW and has zero fade. Bet going hard on an all-wheel large brake kit is akin to the proverbial hitting a brick wall ;-) DAMN!

 

I've got stock brakes, except for stainless steel brake lines. Should I remove my dust shields? I never really thought about it. Would I benefit from this? Sounds like it couldn't hurt.

Henry

 

Yes.

John

 

John,

From what i can tell, the 355 uses a brembo caliper with 36/40 mm pistons. Looking at the picture posted by Philip, (from whom i purchased the calipers, adaptors, tilton adj proportioning valve and bigger bars), it looks like the calipers are not radial mount, just as you indicated. I would very much like to run as big a rotor as i can within a 17 inch wheel, so am thinking about 328 and 313 rotors, possibly Stoptec's. By my rough calcualtions, this would approximate the original stock front to rear force ratio, (1.8 versus stock 1.7). I wil recheck my numbers tomorrow morning when my "head" is a bit more clear

Do you have any advice on hat purchase or manufacturing. I have fired off an email to QvLondon for info on what they have.

Does anyone have experience with seperate/add on parking brake calipers?

Has anyone done the QV 355 to 308 conversion?

Any other advice from guys who have built big brakes

 

absolutely beautiful car u have there. i love the mods. very aggressive but still has taste and class. the brakes also look great the way the fill out the QV wheels perfectly. have fun with it.

 

tagging as reference but ALSO... early in this thread was mentioned uprated sways. How did the Saner units go Mike? i need to upgrade the front/rear sways and have the adjustability as well. Anyone have good sources? Experience?

 

Steven, I have some experience with the Saner bars on other cars. I cannot comment on the 3x8's, but I will add a comment regarding the adjustable end links.

The number of end links on each end do not equate to the number of levels in stiffness. It is merely the length, diameter and radius of the metal itself. That said, if you have two bolt holes on each side, you have three adjustment points: both rear, both front or one front/one rear. With three holes on each side, there are even more adjustment possibilities to fine tune the suspension.

 

Mike,

Roger that and will get the right pair each of 1" greaseable ENS-9-5161G and for the 7/8" will get ENS-9-5158G . Just easier to post here so others can SEARCH it and the info is all here for them. MANY thanks!

Schatten, many thanks as well.

 

More fun...

Am redoing the spring lengths and MAYBE value. With Nick Forza's setup we have 300 lbs. front and 250 lbs. rear. Front is pretty stiff but rear is a bit springy. The nose does dip *a bit* during HARD braking. So the question is:

Who has gone higher in spring rate (and to what) plus what is the front and rear spring length. Right now we have the perches as low as they can go with proper corner weight and we need shorter springs to lower the car further. So we need shorter springs. Anyone know off hand what Nick's stock spring length is (and yes, i will also call him to verify, but it is Sunday and doing research right now.

 

I don't have Nick's shock, but my springs are 450F/400R and I'm pretty happy although I may try 375 in the rear. The fronts are 10", the rears are 12" with about an 1" of thread left in the front and 1/2" in the rear on the shock body, but that only because on my shocks the top 4" isn't threaded due to a large diameter gas reservoir.

If you decide to try shorter spring just keep in mind that they will have less travel. It may not be a problem because your car is lowered so much which reduces suspension travel, so it may work out. You just want to be sure he suspension will hit the snubbers before the spring coil binds. I thing stock the front spring travels about 3'5", the rear about 5.5". Mine are set with the shocks snubbered (if that's a word) to 3.25" front and 5" rear.

 

That should not be true. A 300#/in spring will be a 300#/in spring, the shorter the spring will simply have less travel before it coil binds.

That said, the technical bit is that just making a spring shorter, makes it stiffer, that might be where the stiffer idea comes from. If you just cut a 300#/in 10" spring to 8", it will no longer be a 300#/in spring, it will be 300*10/8= 375#/in. So to prevent this, the spring maker will use a smaller diameter wire to compensate. They may also alter the pitch of the winding, less wraps=stiffer spring, more wraps=softer spring.

 

Steve,

I've got 350 pounders on the front and 300 on the rear but am still running antique 205/70 michelins, so ride (and handling) comparisons are out the window.

360 wheels, spacers, longer bolts are on the way I bought Philip Airey's 355 Brembo calipers and Saner bars, just have to find the time to work out the discs, caliper mounts and drop links.

Mike mentioned the effect of cutting a spring, i iknow he wasnt suggesting it, but don't even think about cutting springs. You will loose the ability of the spring to seat squarely and it will bind on the body of the shock.

best,
chris

 

Would NEVER go the route of cutting a spring. No way!

 

I have 10" 350# springs in the front and 12" 250# springs in the rear. I am going to increase the rears to 300# due to some power on understeer that did not go away with shock tuning. I run QA1 shocks and had to crank the spring perches up pretty high to get the ride height I was after. If your perches are all the way down or close at the ride height I see in your pics, your springs must be either stiffer or longer than mine providing the shock bodies of the Varishocks are similar to QA1.
I think one could and should go stiffer in rates than I am running if they are planning to do a lot of track time and are willing to sacrifice ride quality on the street for a few tenths on the track. My car is not a track car and the only time spent on the track is basically to tune the suspension to give me a balanced street car. My best guess would be 10" 550# in the front and 12" 400# rear. Tune the shocks to the springs and fine tune handling with adjustable sway bars and tire pressures.

Good luck,

John

 

Thanks for the info John! i think we have decided upon 350 lbs front and 300 lbs rear. This seems to be a 'known good.' Ok, so it will be fairly firm on the street but i can adjust the compression and rebound on the shocks for less dampening for the street... then firm it up for the track. Still, i think my dentist needs to check my fillings to be sure they are secure for street driving

 

Actually, I'm 350/250 right now and don't find it stiff at all on the street. Your shock settings for the track and street should be the same. Shocks dampen spring movement and should be the same for street or track. At most you may want to back off a click or two to account for uneven and crappy pavement on the street.
Go to Koni's website and download their shock tuning guide. You will probably find the tuning info helpful. I know I did 15 years ago when I was new to the game. If you fillings are at risk with these spring rates, your bump is set too high or your rebound is set WAY too high and you are experiencing a condition called "jacking down." It basically is a situation where the spring compresses over a bump or thru body roll and the rebound action of the shock overpowers the spring and doesn't allow it to uncoil. Result is the suspension travel lessens and eventually bottoms the shock where the spring rate effectively goes to infinity. I doubt the rebound is your issue, but I bet your bump settings are a bit too high. When tuning mine, I found the front to be very sensitive to increased bump and backing off one click made all the difference in the world.

Just some thoughts...

John

 

I don't find mine to be in any way harsh with 450/400 springs, in fact I've had quite few compliments on how smooth and planted it feels.

I agree with John, you probably have too much shock dailed in. People offen try to use shocks to control body roll and all sorts of other things, but all they are suposed to do is keep the chassis steady by damping oscilations. It sure sounds like you need way less shock, more spring and maybe more roll bar.

 

The Koni link that you provided has a "cliff notes" version if you scroll all the way to the end. Funny, it mentions jacking down also. I just read over it and it will get you pointed in the right direction. DO NOT tune body roll, nose dive, or squat amounts with shocks. Use springs and sway bars. Your fillings with thank me for that advise at the end of the day. Shocks only control the RATE at which this all takes place.

Have fun guys,

John

 

No I don't. I pretty much comitted this stuff to memory many moons ago and most of it has stuck around. ;-) I'll dig around and see if I can find a good version online. Carroll Smith's Tune To Win is also some good reading.

John

 

The magic of Google: http://www.ozebiz.com.au/racetech/theory/shocktune.html

I read over it briefly and it seems accurate. I didn't click on any of the links in the article.

John