m73m95

Sometime in the near future I'm going to do a nearly complete rebuild of my 944. Suspension, brakes, wheels/tires, and LS2 engine.

My current plan for my suspension is to go with 250/300lb springs in the front, and 28 or 29mm bars in rear. For tires I was thinking 245mm in front and 275mm in rear. Its already known that a stock 944 has understeer characteristics, but I want to correct that. 99% of the time my car will be my DD, but I do plan on a few auto-x and track days.

I want it comfortable on the street (I don't mind a stiff ride, just not jarring), and have a more neutral to slight oversteer balance. It also has to support the 70 extra lbs in the front from the LS2 engine, and support the added acceleration in the rear (I don't want it to bottom out when I nail the gas).

Does this sound like a good "slight oversteer" setup, or does anyone have suggestions?

Thank You,

VaSteve

I have no idea how to translate that to set up, but if you're going with an LS2 engine (is that a Corvette?) your standard 944 transmission might not be able to handle it.

m73m95

No no, I know that. I'm using an 951S trans.

I just want ideas or suggestions for the balance of my car with the tire size, and springs I want to use.

BC

I know it would increase the polar moment of the car in total, but whenever I think of doing this I always plan on trying to move existing weight to the rear or removing it from the front to even it out. I think otherwise you may have a terminal understeering car. More rubber in front as well.

But even down to details like Powers steering - put the electric pump at the back, and run the small lines to the rear of the car. Coolant reservior - make it smaller and move it back in the engine bay. Headlights - get rid of the motors for the 944 and maybe do that plexiglass thing.

Doing all those small detail changes, including the battery (I forgot if the batter is in the back or front on the 944) would probably add up incrementally to help the chassis dynamics.

Just a general idea of lightening the front to offset the added weight while moving weight you cannot remove to the rear.

I know there is stuff you can do with the sway bars as well to get a more pronounced turn-in.

I wonder if you could get the aluminum block and heads down to less weight with things like the plastic intake from the LS2 trucks (LQ4), and electric water pumps, etc. Minimal fan motor size on the front with enough CFM, only a small increase in radiator size maybe.

Like I said - small, small details all add up.

BC

Also, I would even out the tire widths. Z-350s do that to remove some of their understeer.

Maybe only 10mm difference in tire size front to rear (not reducing rear though - ADD front width)

I think this would rebalanced the car as well. You will always have that swing arm in the back though. Sorry "Semi-Trailing"

333pg333

I would just find the guys that have done this and quiz them. I don't think you'll have to go to any massive springrate as from what I understood the Chev V8 is about the same weight as a 951 motor?
I would also try this forum. The guys in there are generally very helpful.
http://www.porschehybrids.com/php/in...66ce3906ab2642

m73m95

Thanks for the info guys. I am planning to move the battery to the back, and possibly the GT headlight kit (or something similar).

Also, I'm a member of the hybrids site already. They're good for the engine stuff. I wanted some input from you racing guys on my chassis setup though. My car will mainly be a street car, but it still needs to handle well. I just wanted to make sure I don't get my setup completely wrong.

Its a real car... not rFactor where you can hit "esc" and change springs and shocks in the garage and go out and try it again. I get one shot at this.

RedlineMan

Buy a Camaro;

GM has already done all that.

K-bit

I have a 951 that the PO had put 300# front springs without changing the rears - you could not get the rear to step out - was a great learning setup for myself and my wife for the first few DE's. We now have 29mm bars in the rear and it seems a little tail happy but we also changed to the 30mm front and 19mm adjustable rear roll bars at the same time. Tire size is 225-45-17 and 255-40-17. I am thinking of going to 350# front springs and 245 or 255 at all four corners. It is mostly a track rat but it does see street driving and the ride is acceptable ( has Sparco Evo fixed seats which have very little padding to help with the ride).

smlporsche

I thought the LS1 engine (cast iron block) was about 60# heavier and that the LS2 (Aluminum block) was actually lighter (than a 3 L S2 engine anyway)

Am I wrong?

m73m95

LS1 is still aluminum ... the LT1 is iron.

They say after the swap the front end gains about 70lbs. I've never seen one, so I'm just going by what I've been told.


And thank you K-bit. Thats exactly what I wanted to hear.

dand86951

I have 300# front springs on Leda coil overs with 150# helper springs on the rear using stock 86 torsion bar. Sway bars are 968 M030 front and rear. Tires for the street are the 225 /50/16 and 245/45/16 mounted on BBS RG rims and for the track they are 255/40/17 and 275/40/17 mounted on CCW classics. My car is pretty well balanced with a bit of understeer easily overcome with either throttle or brake. On the street the ride is pretty good but a bit stiff on our terrible roads and great on smoother roads. Having lots of adjustability on the shock damping helps smooth out the road shocks.