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SN95 Teach me: I need more front grip

529
519
Exp. Type
Autocross
Exp. Level
10-20 Years
Kansas City, Missouri
I did my first autocross yesterday since 2019 and I'm pretty sure my first since I redid all my front suspension (the last two years are a blur). I need more front grip real bad but I'm not sure where to start. I guess mid corner grip is ok If I baby it into the corner but then as soon as I get back on the throttle it starts pushing wide on corner exit.

Here's what I'm working with.
3240lbs w/ driver
Eibach front sway bar
MM 1" rear sway bar
425lb front springs
275lb rear springs
Koni SA coilovers
Full MM front suspension with forward offset control arms
295/35-18 A052's on 10.5" wheels
0 toe
-4° camber

216438E3-A2DF-41FE-8A9F-182C6A18B089.jpg
 
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Bill Pemberton

0ld Ford Automotive Racing Terror
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W2W Racing
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20+ Years
Blair, Nebraska
Simple question as you noted first Autocross since 2019 and what tires are you running? Whatever they are , were they new in 2019 or maybe 2018 or 2017? Seen push often with guys Autocrossing or road racing and while doing all the mods the one thing that was not changed/updated was the rubber.
 
417
430
Exp. Type
W2W Racing
Exp. Level
20+ Years
Snowy North
Ok midcorner after you pick-up the throttle if you baby it...but pushes when you drive off indicates that you might need a bit more front rebound damping...all other things being equal,

Lots of variables in your case...but if big push center- off is a problem at various speeds, then increasing front RD by 25% is an easy fix to evaluate. Delay the aft weight transfer for a second or two.
 

Bill Pemberton

0ld Ford Automotive Racing Terror
6,392
5,270
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Blair, Nebraska
Sorry , just noticed you are running Yokes , so pretty fresh rubber and maybe DaveW will jump in with pressures , or maybe a suggestion from RinerAuto above if he has run them or has knowledge?
 
529
519
Exp. Type
Autocross
Exp. Level
10-20 Years
Kansas City, Missouri
Cold pressure was 32 front/ 30 rear. I ordered the larger rear sway bar that Jack at Maximum Motorsports recommended but it's on backorder. I'm going to try less front pressure next time and I maxed out my current rear sway bar so we'll see what happens. I have a few weeks until the next event.
 
4,384
4,775
Cold pressure was 32 front/ 30 rear. I ordered the larger rear sway bar that Jack at Maximum Motorsports recommended but it's on backorder. I'm going to try less front pressure next time and I maxed out my current rear sway bar so we'll see what happens. I have a few weeks until the next event.
not familiar with Yokahamas but that seems awful high all the way around, at least for racing slicks. With regards to bars, I assume your're going to a bigger rear bar, correct?
with the lame stock suspesnion that we used to have to run, these cars would go into snap oversteer on corner exit as the trinagulated 4 link garbage tried to find it's center, I see you've discarded all that,.. good move. While pressures will have an effect on handling, unless you really monitor the psi, and have them nailed down to less than 1 psi, you're better off making gross adjustments, like bars and shock settings.
 

Bill Pemberton

0ld Ford Automotive Racing Terror
6,392
5,270
Exp. Type
W2W Racing
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20+ Years
Blair, Nebraska
DaveW will likely chime in as he has a lot of experience with Yokes , though he is not running them now. He feels they do not telegraph well, but he helps alot of drivers and can give a synopsis of what others are running tire pressure wise. The variances can be huge from one tire brand to another. Actually know some drivers running in the 40s and 50s , pound wise, with certain tires --- not Mustangs, just noting there can be major differences between tire manufacturers, vehicles, suspensions, etc.
 

Mad Hatter

Gotta go Faster
4,311
2,953
Santiago, Chile
So many variables!! I dont now if this helps.. but. When I started going with no rear sway bar: I had terrible under steer and was blaming the suspension, but it was my fault for coming into the corner too hot. After getting used to the car it was ok as I would brake later into the curve loading up the front and then coming out faster.

I guess autocross makes it a bit harder to do, but its the hot tire pressures that really count.
 
4,384
4,775
So many variables!! I dont now if this helps.. but. When I started going with no rear sway bar: I had terrible under steer and was blaming the suspension, but it was my fault for coming into the corner too hot. After getting used to the car it was ok as I would brake later into the curve loading up the front and then coming out faster.

I guess autocross makes it a bit harder to do, but its the hot tire pressures that really count.
Yep, you have to determine what the tire likes hot, then back that off about 2 psi.
 
69
79
Exp. Type
Autocross
Exp. Level
5-10 Years
Virginia
I run Falkens, but pressures could be similar. I run hot pressures at 32 front and 28 rear. Not sure if those are best, but the wear looks pretty good.

I'm also in the process of tweaking roll bars. Autocross layouts are always different so can be kinda maddening chasing a certain issue.
 

Dave_W

Cones - not just for ice cream
520
554
Exp. Type
Autocross
Exp. Level
20+ Years
Connecticut
What do you have the Konis set at? Agree with @RES_22 that all else being okay, power-on understeer correction would be increasing front rebound, to increase weight-jacking / transient load transfer onto the inside-front/outside-rear tire pair. SA Koni Yellow adjustment predominantly affects rebound.

Are you trail-braking all the way to the apex, or are you coming off the brakes during/after turn-in? If you're taking load off the front tires before the apex, it could be the cause of having to "baby it" into the corner.

On the other hand, it could be that both conditions could be cured by bar settings, tire pressures, and/or alignment settings. The main thing that will help diagnosis is to determine if it's (primarily) a steady-state issue or a transient issue. Shocks generally only help in transient conditions; get the steady-state balance feeling good, then tune any lingering transient issues with shocks. Try to do some skid pad testing for steady-state, then figure-8 and slalom for transient.

Lastly, it may also be tuning the driver to the car - do you like to "throw" the car into a corner, do you want/expect the car to rotate early or be pretty stable, how patient are you with the throttle on exit, etc. No judgement, just that people have diffferent driving styles, and a car setup that works for one doesn't for another, and another driver might adapt to both setups (but not prefer either).
 
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That tire pressure sounds extremly low for Yok's, but I havent messed with them in a bit. I started with them at 34f/30r and ended up running a little more like 37f/33r but that was while back. Bob Gosda currently runs them, he may have more input.

THe Falkens are really responding to higher pressures on heavier cars.

DaveW
 
529
519
Exp. Type
Autocross
Exp. Level
10-20 Years
Kansas City, Missouri
@Dave_W This is not from last last weekend but it's probably a good example of my driving and how the car behaves. I would say I have a tendancy to brake relatively late so I'm trail braking into the corner although I'm not a professional driver by any means. The long sweeper at the end of this video right before the finish would be an example of the understeer. I'm barely on the throttle through the whole corner because the front end wants to push.

Here's another one. This course is very similar to what we ran last weekend.
 

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