[GunMetalGrey]

It was my first track day of the season and the first time using my car with SC3R tires, YYZ track/lowering springs and driving with race PTM track mode on

Every time I accelerated out of the same right hand off camber upward slope corner, my car started doing something its never done before; Almost like the rear differential was locked and it was lurching around the corner with some sort of slow wheel hop. I don’t know if something is broken or if there is reduced suspension travel because of the springs (they only lowered it by about 1/2”), but I’ve never experienced that before at this track, I did not notice any other problems and it did this every single time on that corner today. The acceleration also felt particularly slow coming out of that corner.

Any ideas what it could be?

[Move_Over]

Did you recalibrate the MRC after lowering the vehicle?

[GunMetalGrey]

Originally Posted by Move_Over

Did you recalibrate the MRC after lowering the vehicle?

No, my understanding is that you don't have to re calibrate the MRC, have you heard otherwise?

I might have figured out what the problem was; so I was walking around my car and I noticed something looked funny about the tires and wheels... it turns out the dealership that put my new 285 and 305 SC3R tires onto my stock 20 ZL1 wheels decided to put one of the front 285's on an 11' rear wheel and one of the rear 305's on a 10" front wheel!

I never checked the side walls before tracking which means I had a 285 front driver side and a 305 front passenger side with a 305 rear driver side and a 285 rear passenger side the entire track day.

[Move_Over]

Originally Posted by GunMetalGrey

No, my understanding is that you don't have to re calibrate the MRC, have you heard otherwise?

I might have figured out what the problem was; so I was walking around my car and I noticed something looked funny about the tires and wheels... it turns out the dealership that put my new 285 and 305 SC3R tires onto my stock 20 ZL1 wheels decided to put one of the front 285's on an 11' rear wheel and one of the rear 305's on a 10" front wheel!

I never checked the side walls before tracking which means I had a 285 front driver side and a 305 front passenger side with a 305 rear driver side and a 285 rear passenger side the entire track day.

Well that’s ridiculous. You may want to check that 305 inner tire for some wear against the shock.

Still need to re zero out your shocks. The way MRC works is that as your shock gets compressed, the ride height sensor (there’s a sensor on all 4 corners) send a small amount of voltage to your shock (there’s another sensor on all 4 shocks), magnetically charging the fluid which changes the damping force of your shock (whether is be rebound or compression). If you lowered your vehicle 1/2 inch, your car is now riding around like the shock is constantly under 1/2” compression, and never sends the proper rebound voltage either since it’s 1/2” shorter as well.

Definitely worth a rezero of the ride height sensors. I have a good friend of mine that owns a company that does shock sims for corvettes, camaros and all the trucks with magneride suspension. When i changed to DSSV’s (then changed back to MRC) he went through this with me.

[Move_Over]

Here’s a sample of the live voltage you will see when you hook up the scan tool to read the suspension module codes.

You can also rezero it yourself, i think he rents the tool for 100 bucks. It’s 3/4 way down this page.

http://shocksims.com/#software

[GunMetalGrey]

Thanks, I’ll send this info to my mechanic

Or is it really easy to do it yourself?

[davidwarren]

Originally Posted by Move_Over

Well that’s ridiculous. You may want to check that 305 inner tire for some wear against the shock.

Still need to re zero out your shocks. The way MRC works is that as your shock gets compressed, the ride height sensor (there’s a sensor on all 4 corners) send a small amount of voltage to your shock (there’s another sensor on all 4 shocks), magnetically charging the fluid which changes the damping force of your shock (whether is be rebound or compression). If you lowered your vehicle 1/2 inch, your car is now riding around like the shock is constantly under 1/2” compression, and never sends the proper rebound voltage either since it’s 1/2” shorter as well.

Definitely worth a rezero of the ride height sensors. I have a good friend of mine that owns a company that does shock sims for corvettes, camaros and all the trucks with magneride suspension. When i changed to DSSV’s (then changed back to MRC) he went through this with me.

agree. I would look for physical contact on the front. a 305 would move around a pretty good deal on a 10 in wheel. it may be rolling over enough to bind against the strut.

I don't think it would be out of line to ask for a new set of tires. They screwed the pooch on mounting those up.

[Move_Over]

Originally Posted by GunMetalGrey

Thanks, I’ll send this info to my mechanic

Or is it really easy to do it yourself?

Quite easy to do yourself if you rent the tool from shocksims. Should be no reason for a mechanic to get involved (especially if they were the ones that put the wrong tires on the wrong wheels). lol

[Move_Over]

You may have also damaged your differential with two different height tires on it. May want to check that out too...

[TrackClub]

Originally Posted by davidwarren

agree. I would look for physical contact on the front. a 305 would move around a pretty good deal on a 10 in wheel. it may be rolling over enough to bind against the strut.

I don't think it would be out of line to ask for a new set of tires. They screwed the pooch on mounting those up.

Good point: worth trying to ask for new tires, GMG.

Ps We now have 2 separate threads discussing the same issue. Perhaps it would be best to collapse them into one? Up to you, GMG.

[GunMetalGrey]

Haha no, definitely its a different mechanic!

The tire only rubbed when I was turning right as sharp as I could in a parking lot. I never heard or felt anything on the track regarding the front.

I’m not sure how to collapse this thread or merge it into the other one, is it something technical or official, or just a statement I make?

[TrackClub]

Originally Posted by GunMetalGrey

Haha no, definitely its a different mechanic!

The tire only rubbed when I was turning right as sharp as I could in a parking lot. I never heard or felt anything on the track regarding the front.

I’m not sure how to collapse this thread or merge it into the other one, is it something technical or official, or just a statement I make?

Not sure about merging threads. Perhaps just post that this thread is closed and then copy and paste a link to the other one, so folks know where to go if they wanna post something?

The weird thing about the leak is that you noticed nothing until you parked the car at home (assuming i understood it correctly). Usually if something pukes it happens at high loads...

[GunMetalGrey]

Originally Posted by TrackClub

Not sure about merging threads. Perhaps just post that this thread is closed and then copy and paste a link to the other one, so folks know where to go if they wanna post something?

The weird thing about the leak is that you noticed nothing until you parked the car at home (assuming i understood it correctly). Usually if something pukes it happens at high loads...

I'm not the most observant individual, so perhaps this is all I noticed regarding leaks, however what I'm really noticing now is a power issue; the car has less power than it should (when I'm on the street and running warm up laps on the track when the car is still cool) and then it consistently loses more and more power through out each track session. In fact it gets so bad that 10 minutes into the 20 minute session I have to stop tracking the car because it barely accelerates.

It seems to be heat related to me. I think maybe their is air in the intercooler system?

I'll start a new thread about this.

[TrackClub]

Originally Posted by GunMetalGrey

I'm not the most observant individual, so perhaps this is all I noticed regarding leaks, however what I'm really noticing now is a power issue; the car has less power than it should (when I'm on the street and running warm up laps on the track when the car is still cool) and then it consistently loses more and more power through out each track session. In fact it gets so bad that 10 minutes into the 20 minute session I have to stop tracking the car because it barely accelerates.

It seems to be heat related to me. I think maybe their is air in the intercooler system?

I'll start a new thread about this.

That sucks! Best of luck getting it resolved. If this issue first manifested itself when you ran tires in wrong corners, perhaps your ediff is cooked? Albeit any leak in an engine bay is a sign of an obvious issue, as well. You may want to check the ZL1 section, as i recall seeing some posts relative to air in the intercooler issues there. Cheers!