911addict

I am running a standard 3.3 and it feels unstable at high speed (feels light and tramlines, also not confident on sweeping curves at speed)? Thinking initially of doing H&R turbo springs which I believe are 30mm lower.
PS: My garage tells me shocks, alignment, bushes all in good order.

Geoffrey already touched upon lowering the front more than the rear. Has anyone done this?

tjr

Hi Mark,

Mine's got both the 1 bar boost spring and H&Rs (plus a B&B tri-flo muffler). All these mods were done when the car was 3 years old - back in 1995 by G-Force in Aylesbury. The car has done 40k+ miles since then.

I haven't driven a "standard turbo", but I have to say it looks better than standard with the lower springs - especially compared to the federal cars which look like 4x4s! It also feels incredibly stable at all speeds - but again I've nothing to compare it to.

The 1 bar boost spring doesn't seem to have done any harm to my engine - I had a leakdown test carried out by Bob Watson, and I the worst I had was 4% loss on 2 cylinders.

I reckon I've probably got around 340bhp based on what I understand the effect of the boost spring and B&B.

Cheers,

Tim.

911addict

Tim,
what's the B&B Triflow muffler- is it just a silencer bypass, or cat delete?

PS: I've sent you a PM.

SonnyV

I have H&R springs on my Turbo. It looks great and handling very well. I do have the original shocks though, which will be changed soon.

911addict

Sonny,
That's just what I will do. Did you notice a big difference from standard?
BTW do you still have the standard 7 & 9 x 17's?

SonnyV

I still have the Turbo cup wheels 17's. I don't how it was before because the car already had the H&R springs on it when I bought it.

cobalt

With or without the H&R springs your car should not Tramline. How is your tire wear? If it is Ok then something else is wrong your shop is not picking up on. The 964 turbo is a little nervous on long straights especially if the road surfafce is poor and depending on tire brand and size. Otherwise it should feel very stable in the turns. The biggest problem these cars have are the sways are too soft and could use larger bars but nobody makes them for the turbos.

Even with the stock suspension which is stiff and way to high you should not have these problems. The stock springs and Boge shocks have a tendency to hop a bit and the back end can break loose a little to quickly. The H&R springs will not lower your car 30mm without adding the Bilstein HD's or some other height adjustable shock. I think the most you might get out of the H&R's with the stock shocks is 10mm. BTW if you have more than 30k miles on your Boge's than they are shot. The problem with teh Boge's is that before they fail they get stiffer and less responsive.

The factory set the front of the car higher than the rear in the US for DOT bumper reasons. I find the best is to set the front about 1/2 inch lower than the front, you will find at speed the back end will drop 1/2 inch anyhow.

loot87

I'm thinking I'll do the H&R Coilovers for my 91. Is there enough adjustment leeway that I won't be in danger of rubbing? Mine has a stock set-up but doesn't have the 4x4 look. Maybe it's so worn that it's dropped down on its own. I'm running 225/40s on the front and 265/35s on the rear. If I put an 80lb bag on concrete in the trunk, it rubs when I turn.

cobalt

How low is it already? Mine is set to 94 euro ride height which is 20mm lower than stock 91-92 and I am running 235's front with 295's rear no rubbing even when doing autocross which is the most extreme condition.

May I ask why you are hauling around an 80 pound bag of concrete in your trunk?

loot87

Well you know, it's not always convenient to go home and get the truck. I figured it could handle 80 lbs.

I'm not sure how to describe. I'll try to include a picture. How should I measure ride height/

BTW: while searching on Bilstein, I found what looked to be your first post in 2003.

cobalt

Too far back to remember what that was about back in 03.

Just curious. Ride height can be measured from the wheel well arch to the ground on a flat surface. IIRC something like 24.5 or 25 inches is usually a good height.

It should handle 80 pounds + a full tank without a problem.

911addict

Hi Anthony,
thanks for your input.
My car has had tyres checked for even wear and wheel alignment, all good. Shocks are OEM and good. Suspension alignment also fine. New front a-frames and bushes, although RS spec so maybe that explains the sensitivity on crap roads.
The unease in fast long bends could be my own 'bottle' (british word for '*****'!) but my old 3.2 Carrera felt more planted. To illustrate a Boxter S was stalking me at around 100MPH, on the straight I showed him my ***/ superior acceleration but on the sweeper I had to ease off and let him pass me!

The H&R turbo springs are 30mm lower than standard 3.3 euro height, and several rennlisters have told me it will make a big difference.

PS: I'm still unclear as to whether one can lower the front slightly more than the back either on the original springs or with the H&R's. What's the verdict?

nathanUK '81 930 G50

What tyres & what pressures ?

Do you know what your suspension geometry settings were ?

loot87

Bottle? That's the strangest one yet.
Cobalt, I'm measuring 26" on both, so I guess I am at 4x4 height. I'll send a picture as soon as I can take a good one. Tonight, the flash really shows off the lack of effort in waxing.

Do you think the H&R Coilovers can get to 26" or would I definately sit lower on their longest setting?

cobalt

It has been a number of years but IIRC the H&R springs in my car were not much shorter than the stock springs. I do not believe I could have lowered my car to its current ride height using the stock struts and H&R springs. I needed the Bilstein HD's to drop it down and still be able to corner weight it. I do not recall but I believe the Bilsteins will allow you to adjust the car from stock height all the way down to RS spec. Although I think RS spec might be a bit too low for our cars. Correct me if I am wrong but isn't RS height 60mm lower than stock.

Here is a picture before and after the H&R install height adjustment. It is just my opinion but of all the cars I have had with Boge shocks not one had a good ride. I replaced them in each car from my 914 to the turbo and GTS with Bilsteins and found a 1000% improvement. The cost is negligible to replace the shocks since you are already in there and need to align everything anyhow.