mark kibort

I really want to test out pinning and havent had a chance to do this, mainly because the car seemed to be handling ok, and I was afraid of what this kind of change would do to the set up. now with the push being so bad, even with 315 race rubber up front, im willing to slightly toe out or 0 toe the rears or pin the the weisach.

never seen a picture of how this is done. anyone?

I remember Marc T. at Devek talking about needing to pin the rear end when you got the tire size big in the rear, but never really understood the reasoning at the time.

thanks

Mark

heinrich

Wiseacres? What? Mr. Professor Kibort?

Ispeed

3.09

mark kibort

and what would that do except give me a super low 1st gear, and a large gap for 5th which would be taller than my 4th today. (ie 3.2) ?

Imo000

It'll give you enough torque to stop the Earth from turning!!!! I'm going to hide now!

ShawnSmith

What you really need is a 12.3 rear end, causing gear's 1 and 2 to be utterly useless for anything but removing treestumps at 0.2 mph, and making top speed in 5th gear just above the legal limit.... but the theoretical torque numbers will be astounding!

Lizard928

This is easy to do,

But at the same time larger tires will push the outside tie in creating + toe on that tire, thus aiding with rotation..............

As to how to pin. Get out there with a drill and drillbit and drill through the hole that is in the metal sleeve that doesnt go through the rubber and aluminum for the front mounting point. Then insert a bolt and tighten.

As well some guys weld bars to prevent the spring plate from taking much if any load.

mark kibort

creating toe out on that tire when they are "larger"?
doesnt the toe go in under compression to fight oversteer and really, fight rotation?

I'm thinking that just a 1/8" of toe out in the rear, might do the trick. The car is just too tight. with 12" hoosiers up front, you figure it would be loose as goose. Its still pretty tight.

any pictures of the pinning process or result?

mk

mark kibort

The first part would be true, but then , you would still have the same amount of gears and same ratios, same torque at normal speeds beyond the 1st two super gears. You would eventually find a gear like 1st is normally, and there would be no differences. (except not being able to go faster than 3rd gear ) In fact, the nice thing about the stroker 928, is that im at max HP from beginning to end of each gear now, which means, I have maximized acceleration for any speed. almost as good as an IV gear box, but with the downside of having to shift.

ShawnSmith

Nope. Now you have two low gears which are functionally useless, and 3 left, which will somewhat substitute for your former gears 1-3, leaving nothing for speeds above ~90 mph.... dangit.

ShawnSmith

PS - quit telling everyone why the strokers are so wonderful. Yes, we know that full hp is available at almost arbitrary revs... no sense letting everyone else know that. The S2000 crowd will have a heart attack!

pcar928fan

I use 12" front and rear slicks on my race car on totally stock suspension (well the arms anyway... stiff springs like 1000# and 500# or 800# and 400#, and custom valved shocks and lots of - camber up front with a bit of toe out and a bit more than stock caster dialed in) and my car has a VERY, VERY wide stance up front and is REALLY nice under rotation in to a corner! Does not understeer at all but also does not seem overly tail happy either... NICE!

mark kibort

what exactly is your rear toe setting? Of course as I get to the point of overdriving the car, the problem shows. 1 second slower a lap, the car is perfect, but 1 seconds slower.

IN driving Andersons and Fans car, there was no understeer. I know the slicks make a huge difference, and the A6 hooseirs made the push go , almost, away.
Im thinking the only real difference now , is my rear toe. Just too much rear toe in.

Thanks for the data points.

Lizard928

MK,

Think of the rear axle on your 928 going around a hard LH corner.
You have the force PUSHING the RR tire towards the transaxle. The thin lower bar is the spring bar. This bows allowing the tire to move in towards the tranny. When this happens the front does not move in. So the rear moves in the front doesnt. This creates a toe out effect, helping to eliminate understeer in highspeed/highload corners.

I run around 1/16" toe in, or 0 toe in. When my tires were at temp I was able to eliminate understeer with simply a slight bit of heavier trailbraking. That was with 235 up front, and 295 in the rear. (not optimal I know)

GRTWHT

Nice bit of reading guys.

Glenn
'81 928
AU