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Think I 'Slammed" Her a Bit Much...
- Thread starter tony barnhill
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Tony,
If you are planning to carry on with vintage / historic racing in this car it might be a good idea to check the ride height rules and tire rules in the area you will be racing. I found that every sanctioning body has a different set of rules. One rule that affects vintage here is a maximum of 1" lower than stock height. You obviously don't have a problem with removing and modifying suspension (or anything for that matter) but if you could set up now to match your future vintage set-up, you could save yourself a lot of do-overs.
If you are planning to carry on with vintage / historic racing in this car it might be a good idea to check the ride height rules and tire rules in the area you will be racing. I found that every sanctioning body has a different set of rules. One rule that affects vintage here is a maximum of 1" lower than stock height. You obviously don't have a problem with removing and modifying suspension (or anything for that matter) but if you could set up now to match your future vintage set-up, you could save yourself a lot of do-overs.
OP
tony barnhill
Great Pumpkin - R.I.P
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Think I 'Slammed" Her a Bit Much [NEW PHOTOS]
Well, as of now, she's higher (25" front & rear from floor to top of trim line)...all 7 leafs of the original spring are back under her & the lowering blocks I built are back in the almuminum scrap pile...just 'restacking' the rear springs achieved the effect I wanted....& now she's also at the proper height for historic racing!
Oops, forgot photos:
Well, as of now, she's higher (25" front & rear from floor to top of trim line)...all 7 leafs of the original spring are back under her & the lowering blocks I built are back in the almuminum scrap pile...just 'restacking' the rear springs achieved the effect I wanted....& now she's also at the proper height for historic racing!
Oops, forgot photos:
Beware Tony,
As you know I have 2 MG V8's the red one I had the chance to take it around the track in Sebring.At the time the car was level, just like your GT. At around 110 mph the front started to lift and the steering became extremly light, in fact it was down right scary. With fuel in the tank, and rear wheel drive the front will rise, not much but it will rise under accelaration. To cure the problem I raised the back by 3/4" , and the problem did not return, you could do this or lower the front to create a wedge effect. I also did the same on the Silver Lady and have never had trouble although I do have a differant spoiler on this car than on the red one which has the same spoiler as your race car.
Good luck.
Mike Cook
Silver Lady 4.0 ltr V8
Vroom 3.5 ltr V8
As you know I have 2 MG V8's the red one I had the chance to take it around the track in Sebring.At the time the car was level, just like your GT. At around 110 mph the front started to lift and the steering became extremly light, in fact it was down right scary. With fuel in the tank, and rear wheel drive the front will rise, not much but it will rise under accelaration. To cure the problem I raised the back by 3/4" , and the problem did not return, you could do this or lower the front to create a wedge effect. I also did the same on the Silver Lady and have never had trouble although I do have a differant spoiler on this car than on the red one which has the same spoiler as your race car.
Good luck.
Mike Cook
Silver Lady 4.0 ltr V8
Vroom 3.5 ltr V8
jlaird
Great Pumpkin
Offline
110, my god Tony, think of your grandchildren. What you really need is a quickchange raiseing and lowering job. How about air lifts or something along that line? Tis my understanding that this vehicle must compete in different kinds of events? High and low speed and concours.
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tony barnhill
Great Pumpkin - R.I.P
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I got up this morning, looked at the photos, & decided I didn't like all those decals all over her...so, I took most of them off!
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tony barnhill
Great Pumpkin - R.I.P
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Hey, Doc - what's the rule: understeer lower the rear; oversteer lower the front?
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tony barnhill
Great Pumpkin - R.I.P
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Mike - how'd you raise her? Did you add another leaf to the top of the spring instead of to the bottom?
kennypinkerton
Yoda
Offline
[ QUOTE ]
I got up this morning, looked at the photos, & decided I didn't like all those decals all over her...so, I took most of them off!
[/ QUOTE ]
I was wondering when you were gonna do that - hehehe.
As far as understeer or oversteer... I'd stick with level and try it out... then tune from there. At low speeds (autox for example), you'll want a nice balnce of both understeer and oversteer - adjustable by the throttle... The only real problems with one end being higher comes at high speeds (80mph plus)... The rear a tad high will cause a suction effect under the rear of the car giving downforce, keeping the car on the road better... The front a tad high (or sometimes level) at those speeds will cause air pressure build up under the front of the car giving lift... You'll lose steering effectiveness at speeds over 75-80mph... Not good if you want to turn at that speed.
I hope my description helps here.
I got up this morning, looked at the photos, & decided I didn't like all those decals all over her...so, I took most of them off!
[/ QUOTE ]
I was wondering when you were gonna do that - hehehe.
As far as understeer or oversteer... I'd stick with level and try it out... then tune from there. At low speeds (autox for example), you'll want a nice balnce of both understeer and oversteer - adjustable by the throttle... The only real problems with one end being higher comes at high speeds (80mph plus)... The rear a tad high will cause a suction effect under the rear of the car giving downforce, keeping the car on the road better... The front a tad high (or sometimes level) at those speeds will cause air pressure build up under the front of the car giving lift... You'll lose steering effectiveness at speeds over 75-80mph... Not good if you want to turn at that speed.
I hope my description helps here.
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$$$$ for GRM effort... not an option, methinks. But a good solution if "open rules" were in effect.
If you can get it level, Tony, I'd be inclined to agree with Kenny: start from there, and do some "emperical" testing... Thrash it around that airstrip and fiddle the tire pressures a bit first to see if you WANT more over/understeer. Then start juggling spring leaves, etc.
Just a thought.
If you can get it level, Tony, I'd be inclined to agree with Kenny: start from there, and do some "emperical" testing... Thrash it around that airstrip and fiddle the tire pressures a bit first to see if you WANT more over/understeer. Then start juggling spring leaves, etc.
Just a thought.
OP
tony barnhill
Great Pumpkin - R.I.P
Offline
Yeah, you're right - of course....I've got her as level as I can right now (1/2" difference front-to-rear).....think I'll want the front a bit lower...but won't know until I thrash her around...next is pulling the dash to get rid of some of the steering column braces....
Tony.
The way I raised the back was by using a larger "cheese wedge" between the springs and the axle. Are you using this part on your car? it does a great job keeping the prop level under acceleration and helps reduce spring curling.
I am using a 3 degree wedge on the Silver Lady. Looking at your car it looks as though the front could be lowered to acheive the angled body effect that would level out under acceleration. Another question, if you are using this car on tight courses what degree of negative camber are you using?
Regards
Mike Cook
Silver Lady 4.0 ltr V8
VROOM 3.5 ltr V8
The way I raised the back was by using a larger "cheese wedge" between the springs and the axle. Are you using this part on your car? it does a great job keeping the prop level under acceleration and helps reduce spring curling.
I am using a 3 degree wedge on the Silver Lady. Looking at your car it looks as though the front could be lowered to acheive the angled body effect that would level out under acceleration. Another question, if you are using this car on tight courses what degree of negative camber are you using?
Regards
Mike Cook
Silver Lady 4.0 ltr V8
VROOM 3.5 ltr V8
OP
tony barnhill
Great Pumpkin - R.I.P
Offline
Mike - I induced 2-degrees into rear end, same as front end....Dick Leuning is coming down next week to look her over & make suggestions...holding off on suspension until then...he'll know what to do