My C5Z is a freaking animal
10-05-2013, 12:21 AM
#1
Advanced
Thread Starter
My C5Z is a freaking animal
Hey guys,
I will pre-curse by saying I really just want to have a discussion about my c5z, not find an end all answer.
My car is on Pfadt single adj. coils, Johnny O bars, I have only run the car on Michelin PS2's. But man is this thing one difficult beast to drive. It's a new car to me, I've only had it to Big Willow and Street of Willow once each. The first day at Big Willow it was borderline un-driveable at first. I got the tire pressures dialed in and it was better, but should be much faster. Corner exits are absolutely killing me, so much so that at Streets S2000's and and other small 4 cyl cars were actually GAINING distance on me in the straights.
I had the opportunity to ride in another instructors c5z on c6z shocks springs and sway bars i think, also on NT05's, and that car was absolutely planted and just much faster. I think a large part of the issue is the PS2's. Anyone want to ease me and tell me how much more sure footed the car becomes on some real track rubber?
I adjusted some damping and put the rear sways on full soft which will hopefully help, but it's just a downright animal right now.
I should have it out again shortly but this platform has been out in the racing world for a while now so some insight from you guys could be valuable.
I will pre-curse by saying I really just want to have a discussion about my c5z, not find an end all answer.
My car is on Pfadt single adj. coils, Johnny O bars, I have only run the car on Michelin PS2's. But man is this thing one difficult beast to drive. It's a new car to me, I've only had it to Big Willow and Street of Willow once each. The first day at Big Willow it was borderline un-driveable at first. I got the tire pressures dialed in and it was better, but should be much faster. Corner exits are absolutely killing me, so much so that at Streets S2000's and and other small 4 cyl cars were actually GAINING distance on me in the straights.
I had the opportunity to ride in another instructors c5z on c6z shocks springs and sway bars i think, also on NT05's, and that car was absolutely planted and just much faster. I think a large part of the issue is the PS2's. Anyone want to ease me and tell me how much more sure footed the car becomes on some real track rubber?
I adjusted some damping and put the rear sways on full soft which will hopefully help, but it's just a downright animal right now.I should have it out again shortly but this platform has been out in the racing world for a while now so some insight from you guys could be valuable.
10-05-2013, 12:30 AM
#2
Le Mans Master
Has the car had a good track alignment?
Despite now being two generations old, the C5Z is a great track car and when set up correctly, very easy to drive hard.
Mike
Despite now being two generations old, the C5Z is a great track car and when set up correctly, very easy to drive hard.
Mike
10-05-2013, 03:47 AM
#3
Advanced
Thread Starter
One big thing to note, the other car had roll/weight transfer. I mean the thing had brake dive, some roll through the corners compared to mine which literally has nothing. No roll, no brake dive, no squat. I don't think I am getting the benefit of weight transfer the car needs. One big area I am hoping some real rubber will help with. But this is what has led me to set the coilovers to basically full soft in the rear, slightly stiffer in the front and adjust the only adjustable bar (the rear) to full soft.
10-05-2013, 06:57 AM
#4
Drifting
The rear needs toe in. 1/8 to 1/4 total
10-05-2013, 08:00 AM
#5
Le Mans Master
Toe the rear in and I bet it's much better. Where is the toe in the front?
Search for the Pfadt Alignment Sheet, pick your usage, and give it to your alignment guy.
Sent from my MotoX using IB AutoGroup
Search for the Pfadt Alignment Sheet, pick your usage, and give it to your alignment guy.
Sent from my MotoX using IB AutoGroup
10-05-2013, 08:28 AM
#6
Drifting
I agree with the previous two posts about having toe-in in the rear. While I primarily autocross my car, and haven't tracked it for a while, toe-in has been critical to gain a level of comfort for me.
You haven't really told us what the issue is, other than corner exits are killing you. Is corner exit killing you because you have mid-corner understeer, and thus applying throttle causes corner exit push? Or is the car decently balanced mid-corner and then is loose with throttle on corner exit?
If the second case is the issue, then I'd go with the recommendations for rear toe-in.
How is corner entry? Good turn-in and then it pushes? Or initial push - which means you need maybe a touch more toe-out up front?
Stickier tires can't hurt. I don't have experience on the Nittos or the PS2s, so I can't comment on that.
You haven't really told us what the issue is, other than corner exits are killing you. Is corner exit killing you because you have mid-corner understeer, and thus applying throttle causes corner exit push? Or is the car decently balanced mid-corner and then is loose with throttle on corner exit?
If the second case is the issue, then I'd go with the recommendations for rear toe-in.
How is corner entry? Good turn-in and then it pushes? Or initial push - which means you need maybe a touch more toe-out up front?
Stickier tires can't hurt. I don't have experience on the Nittos or the PS2s, so I can't comment on that.
10-05-2013, 09:42 AM
#7
Drifting
I have driven a number of cars over the years, many FWD and I have the Johnny OConnell setup too and I find that the car is very very well balanced. It can break somewhat easy if pushed too hard but in your case I think the tires and alignment are everything. I tried several alignments and found some to be extremely twitchy at high speeds.
10-05-2013, 10:25 AM
#9
Drifting
+ 1 on correct toe settings. The rear Toe OUT may be your problem.
I think the Pfadt settings on their chart confuse some alignment techs. They show negative signs for toe -in, which is not what the techs (and the rest of the civilized world) are accustomed to seeing.
I think the Pfadt settings on their chart confuse some alignment techs. They show negative signs for toe -in, which is not what the techs (and the rest of the civilized world) are accustomed to seeing.
10-05-2013, 11:00 AM
#10
Melting Slicks
While toe out is an absolute no-no in these cars he also could have shocks way out of balance.
In particular, which Pfadt shocks do you have? The more recent "Featherlight" coilovers or the older shocks.
Secondly, what are the shock settings?
If you have the front rebound cranked up too much it will result in oversteer on corner exit.
I suspect it is both of the above, the rear has toe out, and the front shocks are set with too much rebound and that is making the rear end very unhappy. Lots of folks think that screwing shocks to the hard side of the setting is faster and that's absolutely not the case.
These cars are very capable, but if you aren't used to doing suspension tuning, you can make a mess of things in a big hurry.
I doubt it's the tires, unless they are really old and hard. Check the build dates and report back on that too.
In particular, which Pfadt shocks do you have? The more recent "Featherlight" coilovers or the older shocks.
Secondly, what are the shock settings?
If you have the front rebound cranked up too much it will result in oversteer on corner exit.
I suspect it is both of the above, the rear has toe out, and the front shocks are set with too much rebound and that is making the rear end very unhappy. Lots of folks think that screwing shocks to the hard side of the setting is faster and that's absolutely not the case.
These cars are very capable, but if you aren't used to doing suspension tuning, you can make a mess of things in a big hurry.
I doubt it's the tires, unless they are really old and hard. Check the build dates and report back on that too.
10-05-2013, 11:45 AM
#11
Burning Brakes
Like the others have said, sounds like an alignment issue to me. I've driven quite a few C5's at Big Willow and even the nearly stock cars on street tires were planted. Toe out in the rear sounds like a autox setup to get the rear end to come around in slow corners, never heard of anyone running toe out on the track on a C5.
Did anyone else drive the car? If so, what were their impressions? Finally, I'd have the car corner balanced and aligned by a shop familiar with setting these cars up and adjust the shocks back the the baseline setting and then do another track day. I know of an excellent alignment only shop in South Bay if you need one.
Did anyone else drive the car? If so, what were their impressions? Finally, I'd have the car corner balanced and aligned by a shop familiar with setting these cars up and adjust the shocks back the the baseline setting and then do another track day. I know of an excellent alignment only shop in South Bay if you need one.
10-05-2013, 12:31 PM
#12
Le Mans Master
Never trust an alignent shop or guy. Check it yourself even if they hand you a printout.
If you can read tape measure, you can easily check your toe settings.
Fix your rear toe settings and set all 4 dampers to full soft and adjust from there.
You can't really go wrong with Pfadt's recommended settings right out of the box either.
If you can read tape measure, you can easily check your toe settings.
Fix your rear toe settings and set all 4 dampers to full soft and adjust from there.
You can't really go wrong with Pfadt's recommended settings right out of the box either.
10-05-2013, 08:31 PM
#13
Race Director
Never trust an alignent shop or guy. Check it yourself even if they hand you a printout.
If you can read tape measure, you can easily check your toe settings.
Fix your rear toe settings and set all 4 dampers to full soft and adjust from there.
You can't really go wrong with Pfadt's recommended settings right out of the box either.
If you can read tape measure, you can easily check your toe settings.
Fix your rear toe settings and set all 4 dampers to full soft and adjust from there.
You can't really go wrong with Pfadt's recommended settings right out of the box either.
TOE OUT REAR?
10-05-2013, 09:16 PM
#14
Le Mans Master
I had ps2's before and didn't feel very planted w/ them (phadt featherlights,z06 bars). I switched to kuhmo xs all around and differance is huge!! Very planted as well as very controllable when you do get them loose.
10-07-2013, 01:25 PM
#15
Advanced
Thread Starter
I agree with the previous two posts about having toe-in in the rear. While I primarily autocross my car, and haven't tracked it for a while, toe-in has been critical to gain a level of comfort for me.
You haven't really told us what the issue is, other than corner exits are killing you. Is corner exit killing you because you have mid-corner understeer, and thus applying throttle causes corner exit push? Or is the car decently balanced mid-corner and then is loose with throttle on corner exit?
If the second case is the issue, then I'd go with the recommendations for rear toe-in.
How is corner entry? Good turn-in and then it pushes? Or initial push - which means you need maybe a touch more toe-out up front?
Stickier tires can't hurt. I don't have experience on the Nittos or the PS2s, so I can't comment on that.
You haven't really told us what the issue is, other than corner exits are killing you. Is corner exit killing you because you have mid-corner understeer, and thus applying throttle causes corner exit push? Or is the car decently balanced mid-corner and then is loose with throttle on corner exit?
If the second case is the issue, then I'd go with the recommendations for rear toe-in.
How is corner entry? Good turn-in and then it pushes? Or initial push - which means you need maybe a touch more toe-out up front?
Stickier tires can't hurt. I don't have experience on the Nittos or the PS2s, so I can't comment on that.
While toe out is an absolute no-no in these cars he also could have shocks way out of balance.
In particular, which Pfadt shocks do you have? The more recent "Featherlight" coilovers or the older shocks.
Secondly, what are the shock settings?
If you have the front rebound cranked up too much it will result in oversteer on corner exit.
I suspect it is both of the above, the rear has toe out, and the front shocks are set with too much rebound and that is making the rear end very unhappy. Lots of folks think that screwing shocks to the hard side of the setting is faster and that's absolutely not the case.
These cars are very capable, but if you aren't used to doing suspension tuning, you can make a mess of things in a big hurry.
I doubt it's the tires, unless they are really old and hard. Check the build dates and report back on that too.
In particular, which Pfadt shocks do you have? The more recent "Featherlight" coilovers or the older shocks.
Secondly, what are the shock settings?
If you have the front rebound cranked up too much it will result in oversteer on corner exit.
I suspect it is both of the above, the rear has toe out, and the front shocks are set with too much rebound and that is making the rear end very unhappy. Lots of folks think that screwing shocks to the hard side of the setting is faster and that's absolutely not the case.
These cars are very capable, but if you aren't used to doing suspension tuning, you can make a mess of things in a big hurry.
I doubt it's the tires, unless they are really old and hard. Check the build dates and report back on that too.
Like the others have said, sounds like an alignment issue to me. I've driven quite a few C5's at Big Willow and even the nearly stock cars on street tires were planted. Toe out in the rear sounds like a autox setup to get the rear end to come around in slow corners, never heard of anyone running toe out on the track on a C5.
Did anyone else drive the car? If so, what were their impressions? Finally, I'd have the car corner balanced and aligned by a shop familiar with setting these cars up and adjust the shocks back the the baseline setting and then do another track day. I know of an excellent alignment only shop in South Bay if you need one.
Did anyone else drive the car? If so, what were their impressions? Finally, I'd have the car corner balanced and aligned by a shop familiar with setting these cars up and adjust the shocks back the the baseline setting and then do another track day. I know of an excellent alignment only shop in South Bay if you need one.
My mistake!!!! Toe in toe in!!!!
10-07-2013, 02:12 PM
#16
Le Mans Master
I have no idea what is wrong, but a stock C5 Z06 on street tires should run under 1:30 on SoWS.
10-07-2013, 02:58 PM
#17
Drifting
There is something wrong with your car.
I have had three C5 Corvettes with different combinations of Pfadt suspension products and never had any issues.
As others have mentioned the C5 is one of the easiest, most well balanced cars to drive.
On my ST2 Nationals winning car I am running single adjustable Pfadts.
Give Aaron or Blair a call at Pfadt and give them all your equipment and settings and I am sure they can help you out.
I have had three C5 Corvettes with different combinations of Pfadt suspension products and never had any issues.
As others have mentioned the C5 is one of the easiest, most well balanced cars to drive.
On my ST2 Nationals winning car I am running single adjustable Pfadts.
Give Aaron or Blair a call at Pfadt and give them all your equipment and settings and I am sure they can help you out.
10-07-2013, 03:41 PM
#18
Burning Brakes
10-07-2013, 03:54 PM
#19
Melting Slicks
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No disprespect but how many track days do you have? Apologize if I missed it in the post.
Sorry -- just read a couple of your posts. Seems you have a bunch of time at this track.
That being said, if you are confident the alignment is close and the hardware on the car is not defective (bad shock etc) one other problem I have seen is air in the tires causing weird stuff. Don't laugh. If your tire shop filled your tires on a day of high humidity you can get all kinds of crazy things happening. I race an e36 as do a couple of buddies. One of them went from a car that handled very well and in the time it took us to put a new set of tires on the car his set up went to SH*T. We exhausted everything but we found nothing out of whack.
One of the veteran races suggested we evacuate the air from the tires and refill with nitrogen. Actually used an evacuation pump and did it a couple of times to each corner. Well - i thought it was BS but the car was back to normal when done.
Seems what happens is if you get a lot of humidity in the tires they heat up in very irregular ways and at different rates and even ultimate pressures corner to corner. I believe it's an extreme situation for this to happen as it's never happened on my car (same chassis, same set up, etc) but it's worth a try if you exhaust everything else
Will
Sorry -- just read a couple of your posts. Seems you have a bunch of time at this track.
That being said, if you are confident the alignment is close and the hardware on the car is not defective (bad shock etc) one other problem I have seen is air in the tires causing weird stuff. Don't laugh. If your tire shop filled your tires on a day of high humidity you can get all kinds of crazy things happening. I race an e36 as do a couple of buddies. One of them went from a car that handled very well and in the time it took us to put a new set of tires on the car his set up went to SH*T. We exhausted everything but we found nothing out of whack.
One of the veteran races suggested we evacuate the air from the tires and refill with nitrogen. Actually used an evacuation pump and did it a couple of times to each corner. Well - i thought it was BS but the car was back to normal when done.
Seems what happens is if you get a lot of humidity in the tires they heat up in very irregular ways and at different rates and even ultimate pressures corner to corner. I believe it's an extreme situation for this to happen as it's never happened on my car (same chassis, same set up, etc) but it's worth a try if you exhaust everything else
Will
Last edited by Ruby6spd; 10-07-2013 at 04:03 PM. Reason: jumped to conclusion
10-07-2013, 05:35 PM
#20
Instructor
Hey guys,
I will pre-curse by saying I really just want to have a discussion about my c5z, not find an end all answer.
My car is on Pfadt single adj. coils, Johnny O bars, I have only run the car on Michelin PS2's. But man is this thing one difficult beast to drive. It's a new car to me, I've only had it to Big Willow and Street of Willow once each. The first day at Big Willow it was borderline un-driveable at first. I got the tire pressures dialed in and it was better, but should be much faster. Corner exits are absolutely killing me, so much so that at Streets S2000's and and other small 4 cyl cars were actually GAINING distance on me in the straights.
I had the opportunity to ride in another instructors c5z on c6z shocks springs and sway bars i think, also on NT05's, and that car was absolutely planted and just much faster. I think a large part of the issue is the PS2's. Anyone want to ease me and tell me how much more sure footed the car becomes on some real track rubber? I adjusted some damping and put the rear sways on full soft which will hopefully help, but it's just a downright animal right now.
I should have it out again shortly but this platform has been out in the racing world for a while now so some insight from you guys could be valuable.
I will pre-curse by saying I really just want to have a discussion about my c5z, not find an end all answer.
My car is on Pfadt single adj. coils, Johnny O bars, I have only run the car on Michelin PS2's. But man is this thing one difficult beast to drive. It's a new car to me, I've only had it to Big Willow and Street of Willow once each. The first day at Big Willow it was borderline un-driveable at first. I got the tire pressures dialed in and it was better, but should be much faster. Corner exits are absolutely killing me, so much so that at Streets S2000's and and other small 4 cyl cars were actually GAINING distance on me in the straights.
I had the opportunity to ride in another instructors c5z on c6z shocks springs and sway bars i think, also on NT05's, and that car was absolutely planted and just much faster. I think a large part of the issue is the PS2's. Anyone want to ease me and tell me how much more sure footed the car becomes on some real track rubber?
I adjusted some damping and put the rear sways on full soft which will hopefully help, but it's just a downright animal right now.I should have it out again shortly but this platform has been out in the racing world for a while now so some insight from you guys could be valuable.
When your other driver also went slow, there is something other than the normal wrong.
Jim M.