MrAWD

Nice pic!

But, if that rear wheel is up in the air already, going stiffer with the bar will not help much. I would consider extra 100 lb or so rather than a bar change.

kyoo

iTrader: (29)

it'll still be different even if the wheel is already in the air. my mini lifted in every stiffness setting, from soft to stiff. it still makes a difference, the rate still changes

MrAWD

Lots of ways to skin the car...this is why all of this is so much fun!!

Jim3142

iTrader: (2)

I agree that there's probably some diminishing returns with going stiffer on the rear bar, but I'm not sure I'm there yet. So far, more rear bar has helped so I'm hoping that change plus less rear camber will get it closer to where it needs to be.

Jim3142

iTrader: (2)

Well, the changes made a positive effect in the car's handling this past weekend . Usually it pushes a ton at Crows Landing but it was pretty well behaved there and even caught me off guard with some oversteer that I wasn't expecting. On Saturday, I had Bryan Heitkotter hop into my car (we drove his 350z in the morning, my car in the afternoon) and he was able to beat his morning time by .1xx (not a test, so no control run in the 350z after running the Evo). We think the car is competitive

Bryan (No video of his fastest unfortunately, but this run was only .5 slower):


Me:

kyoo

iTrader: (29)

that is VERY interesting. are you on 93 btw?

also, you did go ahead and switch to the stiffest setting on the rear bar it sounds like?


thanks for the upload. he rode the **** out of your limiter at one point there lol. would have been amazing if you had data. one thing i feel like i noticed - he gets on the gas early, and once he's on the gas, he's on it - no letting go.

MrAWD

Hi Jimmy,

This was posted on the other forum were your car was mentioned when Brian drove it. In the case you didn't see it, here you go:

Jim3142

iTrader: (2)

We don't have access to 93 octane out here, I have tunes for 91 and 100. Car was on the 100 octane tune in the videos above, wanted to get Bryan's impression of what the car is like for National events, since he drove his car + Lane Borg's C5 + John Hale's STi at the STU car test at Nats on the practice course.

And yep, I went to the stiffest setting on the rear bar. As for throttle, he is very aggressive with throttle and has like a 6th sense for feeling out if a car will stick in a corner at certain speeds. Riding with him in his 350z was nuts


I saw that post from Mike (I occasionally lurk there ), I didn't think it was hopping on entry on Saturday but on Sunday it was hopping in some sections, though Crows does have some really bumpy spots. However, I noticed that it would hop if you tried to take an element at pretty high speeds (Bryan took the showcase at 60-ish MPH with only a lift on his first run, car was hopping like crazy ). What was more noticeable was the inside rear wheel's behavior after I stiffened the rear bar - when we were getting on the gas on corner exit or in transition, it felt like the inside rear would come down but it would bounce off the ground once or twice before settling. Maybe something that can be helped by changing some shock settings in the rear? I'll have to try it again at the next Crows Landing event on 11/4-5.

My other idea is to go slightly softer in terms of spring rates - dropping 100 lb/in on both ends would reduce my overall roll stiffness but I would end up with more rear bias in terms of roll stiffness. Plus it should ride better lol

Another thing I noticed was that the rear edges after this weekend were looking about as bad as the front edges (I dropped rear camber from -1.7 to -1.4). Having a bigger gap between front and rear roll rates might let me run a little more rear camber but keep the amount of rotation I'm getting now. Lots of things to think of and try for next season

MrAWD

I wouldn't drop spring rates yet, but rather soften the low speed compression. If you can add some more rebound along the way, I would do that too! If your rear wheel was dropping down fast enough to affect high speed compression, I would take out some of that too!

Dallas J

iTrader: (1)

By now most should know my stance on the subject, but I think the issue is spring rate and roll center. Too much spring is making the front tires act as the spring, no amount of shock adjustment will fix that. Add too low of roll center and you are driving down the outside tire as well as it being the most loaded. Also causes the rear inside to lift higher (wobbly table effect) and now you have a teeter-totter.

kyoo

iTrader: (29)

got any plots of the diff bw 91 and 100? 100 is going away as u know..

Jim3142

iTrader: (2)

Unfortunately I don't have triple adjustables, but I may play with the compression and rebound settings at the next event. Currently I'm at 4/14 from full soft in the rear but 8/14 from full soft in the front, for compression.


I think you posted this before we talked on Messenger today, but the next step (after adjusting the rear ride height) is probably to soften the springs all around.


I don't have it handy at the moment, but the car makes about 20whp at the peak on the 100 map than it does on 91; it was tuned on the same Mustang dyno by the same shop for the 91 and 100 octane tunes. I know 100 is going away, but it's still legal for the rest of this year - the plan is to retune for 91 (once the open ECU rules are confirmed, hopefully in next month's FT) with the MAP o2 eliminator downpipe that I've had sitting for awhile and see how close I get to what the 100 map got me. If it's close, then I'll probably just stick with 91, but if it's a-ways off, then I might just bite the bullet and get tuned for a mix of 93 (we don't get 93 on the West Coast, and our 91 sucks). The new 93 octane limit isn't set in stone yet though, as Marshall pointed out in the STU thread - the BOD still has to approve the changes.

griceiv

iTrader: (2)

I think the hopping is a combination of all of the things you mentioned, including shocks. the hopping is worst when the shocks 'lock out' and force all the damping into the tires (which obviously doesn't work all that well), but with correctly setup shocks you can raise the spring rate threshold that the hopping starts.

I actually switched away from the ohlins to a set of cusco zero-3x that are rebuilt by Guy Ankeny at FRSport. very happy so far.

Jim3142

iTrader: (2)

Marshall, when you say "correctly setup shocks", do you mean rebound/compression settings, valving, or something else?

Butt Dyno

iTrader: (10)

I'll be interested to see what you find here - at 600/800 I found I was out of adjustments in Toledo other than jacking up the rear tire pressures. (which inspired me to go to 700/900) That was with -1.5 in the rear though, less probably would have been better. That was also on 245's.

https://www.maperformance.com/produc...vo-8-9-evo-o2e
Is that the right one?