suspension settings- modified engines
Discussion
Do any of you who modded the engine of your Griff, let's say over 320 real bhp, know what suspension settings you are running? From the bible I know that standard is 20 min. toe in (front and rear) and 3/4 degree negative camber (front and rear).
Don't know what my current settings are but with all the extra power the car is all over the place once you really push it. Also seems quite unstable under heavy braking sometimes.
thanx guys.
Don't know what my current settings are but with all the extra power the car is all over the place once you really push it. Also seems quite unstable under heavy braking sometimes.
thanx guys.
could be those shocks are getting tired, also bushes as per nics comments.
any wear in the suspension will be amplified by a heavy foot and more BHP!
the car should be able to handle that kind of power ok, if alls well. lowering/stiffening etc is really for track work, not too beneficial on the road.
any wear in the suspension will be amplified by a heavy foot and more BHP!
the car should be able to handle that kind of power ok, if alls well. lowering/stiffening etc is really for track work, not too beneficial on the road.
Unstable under braking indicates that the problem is nothing to do with the power. It probably is a geometry problem, it only takes a small amount of toe-out to produce some really alarming handling. Worn bushes can result in the geometry changing under load so what you measure when stationary may not be what you're getting on the move.
GreenV8S said:
Could it be that the geometry setup was disturbed when taking out the engine?
No, I haven't since I'm a total nono in these things and there is no TVR service point in this area. I'm having someone who knows TVR's set up my car beginning of April. Just wondered what settings you guys are running.
chevtrev said:
Could you please explain how this would happen.
I've no idea what was removed to give access to the engine bay. They could have unbolted removable chassis members and refitted them with weight off the suspension, they could have disturbed the rack. I'm sure it's possible to do the work without disturbing the settings, but taking an engine out is quite a big job and it's quite possible that something was shifted while they were at it. I don't think it's particularly likely, but if the handling feels different afterwards then tyre pressures and geometry are obvious things to check (along with bushes etc).
GreenV8S said:
Could you please explain how this would happen.
I've no idea what was removed to give access to the engine bay. They could have unbolted removable chassis members and refitted them with weight off the suspension, they could have disturbed the rack. I'm sure it's possible to do the work without disturbing the settings, but taking an engine out is quite a big job and it's quite possible that something was shifted while they were at it. I don't think it's particularly likely, but if the handling feels different afterwards then tyre pressures and geometry are obvious things to check (along with bushes etc).
Something must have changed: I checked tyre pressures and tried any setting from very soft to very hard and everything in between. First I thought the new Toyo's at the rear were to blame but they have now done 5.000 km and are fine I think. Handling before/after the repairs are like day and night (so is the power by the way). Now have new Toyo's on the front too and I must say handling has definitely improved, although it's still far from good. Will report back after the suspension checkup.
BTW Pete, did adding a turbo affect the handling of your car? If so, what did you change to counter that? What kind of power did you have now? (and will we see it at Zolder this year?)
>> Edited by gerjo on Friday 17th March 18:31
>> Edited by gerjo on Friday 17th March 18:34
gerjo said:
BTW Pete, did adding a turbo affect the handling of your car? If so, what did you change to counter that? What kind of power did you have now? (and will we see it at Zolder this year?)
Every time I increase the power I end up moving more roll stiffness to the front to help me get the extra power down out of corners. Unfortunately it isn't looking good for Zolder this year, I still have some more jobs to finish before it is ready for a long trip and I've just spent far too much money on a new workshop (with three bedrooms attached) so I'm going to have to cut back on the spending for a while.
Edited to add: Haven't measured it but I would guess power is in the low 300s, torque in the high 300s. That's guesstimated from the boost level, backed up by the 'oh sh!t' factor driving it.
>> Edited by GreenV8S on Friday 17th March 18:49
are the tyre sizes identical on rear, to before? ie 245/4516 ??
if you've gone from a 225 to 245 in a 45 the tyre will be bigger lifting the rear.
a 225/45 will be around 1cm smaller than a 245/45.
this will make it very light at the rear and pitch on heavy braking.
andy
BTW i have -2f and -1.5r degree camber, but i believe -1/2 to -1 was std.
20 degrees toe in front (oops, thats 20mins toe in
) which is factory spec
andy
>> Edited by Guillotine on Friday 17th March 21:08
if you've gone from a 225 to 245 in a 45 the tyre will be bigger lifting the rear.
a 225/45 will be around 1cm smaller than a 245/45.
this will make it very light at the rear and pitch on heavy braking.
andy
BTW i have -2f and -1.5r degree camber, but i believe -1/2 to -1 was std.
20 degrees toe in front (oops, thats 20mins toe in
) which is factory spec andy
>> Edited by Guillotine on Friday 17th March 21:08
Guillotine said:
are the tyre sizes identical on rear, to before? ie 245/4516 ??
if you've gone from a 225 to 245 in a 45 the tyre will be bigger lifting the rear.
a 225/45 will be around 1cm smaller than a 245/45.
this will make it very light at the rear and pitch on heavy braking.
andy
hi Andy,
Yes, they are identical. I have Toyo's for a few years now, 225/45/16 front and 235/45/17 at the rear. Had Proxes T1-S at first and thought they were absolutely perfect; put T1-R's at the rear when the engine was rebuild, so I blamed the R's for the bad handling but I don't think this is the case. Now have the R's on the front too and as said a bit better now.
thanks for the settings, will bring the numbers along.
>> Edited by gerjo on Friday 17th March 19:04
starmist said:
Might just be that all it needs is a geometry check. I ended up going down the Nitron / Polybush route, but that's serious wedge - isn't it Guillotine?
Yep, I hope so. I have a fully adjustable Koni sport suspension, developed by Koni Race Dept NL especially for the Griff, so chances are we will find the right (new)setting. Clive in Spain (former TVR dealer) will do it; he has a nice test track and does quite some development work for various car manufacturers and racers.
v8 racing said:
gerjo i go back to your first post about about running the front wheels toe in? this is a BIG NO NO, any rear wheel drive car has to run toe out or at the worst straight, although this wont explain the problem under braking, engine power is regardless at this point!
hi Rob,
I copied this from Steve's bible as being the factory recommended settings. Steve makes a remark in the same text that some dealers indeed claim that it should be set to zero at the front, but he finds the factory setting "to be excellent".
gerjo said:
gerjo i go back to your first post about about running the front wheels toe in? this is a BIG NO NO, any rear wheel drive car has to run toe out or at the worst straight, although this wont explain the problem under braking, engine power is regardless at this point!
hi Rob,
I copied this from Steve's bible as being the factory recommended settings. Steve makes a remark in the same text that some dealers indeed claim that it should be set to zero at the front, but he finds the factory setting "to be excellent".
All the race cars i have ever set up or driven/raced i always set up parralel or slight toe out, makes the car far more responsive on turning into a corner
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