Impressions after a few laps

[scottiec]

Hey Gang,

Did some instructing yesterday over at the Shenandoah Circuit at Summit Point. I figured it would be a good time to shake it down and want to share my impressions and opinions. The cool part about it, is my car hit 1000 miles while on the track.

Brakes - I need a more aggressive front pad that will stand up to the temps. After about 3 laps I was getting brake fade. My rear brakes are hp+ I believe, but my fronts are RockAuto's PowerStop (the performance pad). Honestly, I'm not surprised. So I am going to look at some new pads such as the g-loc.

Master Cylinder- I have a jeep mc on it, and it was overflowing brake fluid because it seems there was not a good seal. Anyone have any recommendations?

Handling- The car handles great, for the most part. I have the 3 link set up with the nittos. The handling was predictable, but I was really not thrilled with the understeer I was getting. Some of this could be related to tire pressure (cold was 24), some of it could also be related to my expectations (raced spec miata before doing this). Oh yeah, I could also just be too aggressive on my inputs and need to drive this car a little differently.

The best part about the day is EVERYONE came to look at my unfinished gel-coat car and tell me that it sounded absolutely incredible on track.

[Jeff Kleiner]

Cool, sounds like a good day

RE: Handling and understeer---Which Nittos? What springs? What are your alignment settings? And yes, you are correct that abrupt steering inputs can induce understeer.

Jeff

[GoDadGo]

Hey Mr. Scott,

Loved reading your 1st impressions of your car on the track.
Being a drag racer at heart, turning left and right is somewhat foreign to me, but I am willing to learn.
Also, please share with us the set up for your car because I'd really like to see "What-Cha-Runnin!"
Finally, glad you had a great time and thanks for motivating me to swing some wrenches.

Steve

[scottiec]

Jeff and Steve

I am running the nitto 555 g2’s. For shocks and springs I am using what came in the kit, I don’t remember what spring rate they are. My alignment is -1 degree of camber and 3.5 caster. My toe is either zeroed out or 1/16 in (can’t recall)

[Jeff Kleiner]

Jeff and Steve

I am running the nitto 555 g2’s. For shocks and springs I am using what came in the kit, I don’t remember what spring rate they are. My alignment is -1 degree of camber and 3.5 caster. My toe is either zeroed out or 1/16 in (can’t recall)

So you are basically "by the book, right out of the box" which is prone to understeer. The G2 tires are going to be limited as far as track work. You can take out some push/free up the rear end by going to a higher rate rear spring ---factory is 500# front, 350# rear. I run 750 front/500 rear -1.5 camber, +8 caster (power), 3/32" toe in and am neutral to a little loose on Nitto NT-01s.

Jeff

[scottiec]

Jeff

Thanks so much for the sound advice. Are your fronts also 245? Also good to know that it is prone to some understeer and not my car specifically

[Gordon Levy]

I have a master cylinder that works much better. If you are doing track work you really need to be running Wilwood or Motul brake fluid.
You are running too much tire pressure. Should start out with somewhere around 20psi cold and be in the 24psi hot range. A pyrometer is really necessary to get pressures dilled in.

[scottiec]

I have a master cylinder that works much better. If you are doing track work you really need to be running Wilwood or Motul brake fluid.
You are running too much tire pressure. Should start out with somewhere around 20psi cold and be in the 24psi hot range. A pyrometer is really necessary to get pressures dilled in.

Gordon, can you send a link to that mc? I can’t find it on your website

[Gordon Levy]

It's a Wilwood piece I use in my builds. Please feel free to call me is you want to talk about it.

[dallas_]

A pyrometer is really necessary to get pressures dialled in.

That is some advice you gave me earlier, and I can attest that it really works. Can't imagine trying to get tire pressure right without one.

[GoDadGo]

Scott,

What is your stagger front to rear?

245/45-17 Front and 315/35-17 Rear

Also, what driveline are you running?
The reason I'm asking is that my C/G is 50/50 because of where I have my engine and transmission sitting.

Steve

[GFX2043mtu]

You say the car pushes to much so my first thought is you aren’t by any chance running a front sway bar only?

[scottiec]

Yes that is my stagger.

No front sway bar.

[GoDadGo]

Yes that is my stagger.

No front sway bar.

Thanks Scott!

I've got the same 3 link set up (Stock Factory Five) but have got a lot less rubber out back (285/40-17s) with the same (245/45-17s) up front.

[Jeff Kleiner]

Jeff

Thanks so much for the sound advice. Are your fronts also 245? Also good to know that it is prone to some understeer and not my car specifically

255 Front and 315 Rear. I don't have any experience with the G2 tire but as for my NT-01s and the Kumho XS which I have also run I concur with Gordon RE: pressure (at times I ran the XS down into the teens).

Jeff

[Duke]

I have a master cylinder that works much better. If you are doing track work you really need to be running Wilwood or Motul brake fluid.
You are running too much tire pressure. Should start out with somewhere around 20psi cold and be in the 24psi hot range. A pyrometer is really necessary to get pressures dilled in.

Gordon, quick question. What pressures do you typically aim for with these when you are running a set of slicks (Hoosier R7's)? I'm assuming 24/25 hot (again, ballpark depending on temps)

[Gordon Levy]

usually 23/24 hot. I have started as low as 16psi cold. Up or down 1-2 psi depending on track and what the pyrometer says.

[scottiec]

This is really informative. Thanks guys

[Gordon Levy]

One last thing, is you are running the standard 500/350 FFR spring package and feeling a push, you probably need to change your entry into the corner. Push tends to happen if you are late braking to far into the turn. Get you braking done before you turn the wheel into entry and throttle off the turn. You should be able to induce a little neutral to oversteer coming off. Basically slow in fast off. These cars to tend to be a little unpredictable if you try to trail brake them.

[scottiec]

Gordon,
Thanks. I was most likely trial braking and not noticing I was doing it out of pure habit

[CraigS]

275 fronts would also help.

[GoDadGo]

Gentlemen,

This is very useful information since most of us don't road race and will likely never do much more than a limited track days.
Would any of you consider doing a thread regarding the Driving Do's & Dont's of these little pocket rocket dream cars that we are building?
Your collective racing knowledge could help more than a few of us stay on the road and out of the ditches.
Just a thought from the peanut gallery.

Steve