Chris Prack

No aero, 1100lb springs and a 305mm tire.

I think part of the issue here was lack of weight transfer. 1100 is a lot on the rear of a 951. Add in the fact is was a lightened car and no wing. IMO your rear suspension was acting like it was solid. If you do have a droop issue then it seems the cards were stacked against you.

For a comp I built a 951 several years ago with an ADL and everything that goes along with it and then some. 2600lb car running 335 Dot Hoosiers with a Crawford wing we only needed 900lb/in springs on Koni 3011's to get roughly 35 mm worth of compression travel.

Dropping spring rates is easier than adding the wing. I think that is where I would start after you get the droop issue figured out.

333pg333

Thanks a bunch for the intel Chris and nice to see you posting back here.

333pg333

Oh, just to add to this. There is a particular fast road/track 951 which was put into the hands of a suspension analyst who suggested to go with the 850lb front springs that he should increase the rears to 1200lbs and even 1400lb on certain tighter tracks. I believe it was largely based on matching front and rear spring rate frequency (which as most readers would note doesn’t get much of a mention in these pages). This was not on a race car but as I said, a fast road / track weapon. No aero to speak of and running on R spec rubber.
It will be interesting to see how this progresses.

333pg333

Just a bit of an update. Things have been moving slowly for one reason or another but we did some basic measurements today. Putting all the 'stuff' in a pile, shaking it up and seeing what results, I think the reason I came off the track was due to the inside rear wheel having minimal or no contact at times during some cornering. This I believe was due to a sort of domino effect. Bear with me.

So back when we decided to change the car from a road / club car to pretty much a race car I flip flopped about trying to decide what to do with the bodykit in that I wanted to go up to a wider track. So in the end due to not a lot of choice I went with the B/foot GT2 kit and as things happen, I also sort of ordered the Fikse wheels at the same time as they were running a special on them through B/foot. My intention was to do some door to door racing and I was restricted to 44" total wheel width. So I went for 10.5" / 18" fronts and 11.5" / 18" rears. Fikse said fine and that they knew the right offsets as they'd worked with B/foot before. B/foot says that you can run 11" / 12" with their kits also. So anyway fast forward 18 months and we're readying ourselves for the first track outing. The builder had done his best to get clearance for the front wheels and in the end had to raise the ride height a little in the front. So of course the rears got raised similarly to maintain balance. Anyway, enough backstory.

So today we measured the ride height and rear travel from resting ride height to jack-it-up droop. So the droop was only 15mm or 0.6". To me this seems very little but I'm learning that we work in smaller increments the more race oriented suspension we move to. We also found out that my car was sitting 170mm off the ground at the front (measured to midway through the bolt connecting the A-Arm to subframe) compared to JET's 145mm. The rears were 275mm from midway through the bolt connecting the trailing arms to the T-tube carrier compared to Sean's at 245-250mm. He also said that his similarly measured droop is 25mm.
So...I know it doesn't sound much different but it would seem that due to not having the clearance for the front wheel/tyres to turn sufficiently at a more desired ride height, we had to raise it and ergo, wheel lift. Tough lesson!

So, my next choice is how to replace the body work. I have bought another set of B/foot GT2 flares but there's no point repeating the process. I'd like to go for a more complete widebody but it just doesn't seem like there is a good quality off the shelf kit available. Waiting to hear how Tony G goes with his new kit that he bought from B/foot. I'm tempted to go for some of the same front fenders that he used from A.I.R. that are an inch wider and then put the GT2 flares on. The rears could do with a little padding too but I don't want to have the flares on the front only. I actually quite like the look also. So we might massage the rear metal guards before putting the flares back on. Anyway, I'm seriously hoping that the extra clearance will allow us to drop the ride height and regain sufficient droop.

NZ951

That all well and good, but did you see the All Blacks nail the Irish 60-0?

Paulyy

What about the CF kit that Jan sells?

333pg333

Watched the first 5-10 mins. Pretty tight. Went out. Saw the result. Crazy!! Think the Paddy's played their grand final last week.

Link?

ehall

HAHAHAHAH!!!!

ehall

Patrick, based on that wreck, you need to RUN as fast and as FAR AWY as you can, from how the car LOOKS! It tried to kill you when it was freakin beautiful!
Make the damned thing WORK!
If the AIR route gives you what you need, than guess what.....

OZ951

Hey Patrick, just thought I'd pop in to see how your getting along since your incident. Looks like you've chosen the live & learn path (good to see btw). By the time you've got your car sorted I won't be that far from joining you at Eastern Creek I reckon. Good luck with getting the car back together.

Paulyy

http://www.rsr-racing.net/

I thought you bought door skins from him?
he sells the whole wide body kit front and rear fenders.

Good to see you still browsing the 951 forums Wayne. Eastern Creek is in NSW and IICR you're from SA?

OZ951

Hey Paulyy, yes I'm from SA, just like your car (actually your car is originally from the UK), but when I get back to oz I expect to be working in Canberra or Glenbrook NSW, either way Eastern Creek will be the track I'm heading for. Phillip Island will be on the list though, so may see you there if your heading that way.

95ONE

Patrick, why are you not buying the 2" wider front fenders from GT? Allows a 78" track width in front. A little more if you're crafty. (87+ suspension)

333pg333

Yup, definitely. Just need to decide which particular route to go with.

Thanks Wayne. Be great to catch up and do some track days for sure. They've made some changes to Eastern Creek too so a bit more variety.

Didn't have the easiest time with those doors. Can't see the whole kit on his rather rudimentary site? He seemed a nice enough guy but the doors started off cheap and wound up expensive. They're still sitting in the workshop.

Bruce, I was waiting for a really nice widebody kit to become available. I viewed the GT2 flares as a bit of an interim solution (which didn't quite work out) and actually really like the look of them. To add, I've got these wheels that are a certain size so if I went too wide, they'd get swallowed up which is a look I hate. Sure you can use spacers but I start to wonder how safe running big spacers are with big grippy tyres putting a lot of strain on our undersized CVs and axles. (I could also send away for a wider outer shell from Fikse I guess.) That's why I'm sort of thinking of using the AIR fenders and the GT2 flares together. Also the B/foot nose panel is meant to add a further bit of clearance either side, but I'd assume this is at the front of the guard. My wheel clearance issue is actually at about 11-1pm on the top of the wheel arch. I actually prefer the look of the stock nose than theirs, but may use it anyway. Then, oneday when there is a sufficient widebody kit available I might make the switch. At least this is my current thinking. I'm pretty sure Tony G bought the B/foot GTR widebody kit recently and I was looking forward to hearing how well that worked...but it looks like he's bought the LandJet car so perhaps there will be some differences in his plans now? Maybe he'll have a spare kit...

333pg333

Prof Fred (industry lurker) requested a pic of where we were taking the rear ride height measurements from. Fronts were mid point of the bolt that joins the A Arms to the sub frame.
Be interesting to know other people's ride heights??