6 replies to this topic

[Keith Novak]

After several years of racing it, I'm fairly confident my '95 is bent.  Even with all new suspension bits it's virtually impossible to get it level without an extra 100# or so on the FL tire, and to get a reasonable cross I have to drop the FL corner quite a bit, which has its own set of handling issues.  By comparison, my '99 is very easy to get a good corner balance while staying level.  These are the only 2 cars I've ever tuned so either:

1. The '99 is just a much more balanced car out of the box.  or
2. My '95 isn't so straight after its street life, then several years of a new racer hitting a few tire walls, embankments, other cars, holes, woodland creatures...

If the car is in fact twisted 1/4 inch or so, is that something that's relatively easy to get straightened or is that within the margin of error for most frame shops so it's unlikely to get much better without luck?

[Jim Drago]

After several years of racing it, I'm fairly confident my '95 is bent.  Even with all new suspension bits it's virtually impossible to get it level without an extra 100# or so on the FL tire, and to get a reasonable cross I have to drop the FL corner quite a bit, which has its own set of handling issues.  By comparison, my '99 is very easy to get a good corner balance while staying level.  These are the only 2 cars I've ever tuned so either:

• 
  
• The '99 is just a much more balanced car out of the box.  or
• My '95 isn't so straight after its street life, then several years of a new racer hitting a few tire walls, embankments, other cars, holes, woodland creatures...

If the car is in fact twisted 1/4 inch or so, is that something that's relatively easy to get straightened or is that within the margin of error for most frame shops so it's unlikely to get much better without luck?

Keith
The 99 is easier to get corner balanced as typically you are running much more ballast. <180 lb driver can get almost perfect corner weights. Not as easy NA car as you don't have as much ballast typically.

If NA car is in fact bent, it is not a hard fix.
Jim

[Steve Scheifler]

Exactly how are you determining level?

I'd like to know what the frame places measure from on these cars. One place said the pinch welds, I assume meaning as the basis of determining a centerline only.

[Keith Novak]

Keith
The 99 is easier to get corner balanced as typically you are running much more ballast. <180 lb driver can get almost perfect corner weights. Not as easy NA car as you don't have as much ballast typically.

If NA car is in fact bent, it is not a hard fix.
Jim

My ballast between cars is only about 20lb difference but good to know I should be able to get it straighter.

 

 

Exactly how are you determining level?

I'd like to know what the frame places measure from on these cars. One place said the pinch welds, I assume meaning as the basis of determining a centerline only.

On level pads, I've set it up with all spring collars set to the same height to see where it starts out. I've measured to the pinch rail (unbent areas) to a level between scale pads. I've measured the shock cylinder to bump stop clearance.  I've done it enough times now that I've calibrated my fat hands to tell the bump stop clearance by how much I can fit between the tire and fender.  Everything tells me that the FL seems bent down compared to the FR including that there is always more camber available in the FR than the FL.

[Bench Racer]

In the rear of the FSM Body section there are two dimensioned sheets, one sheet for horizontal and one sheet for vertical dimensions. No tolerances included.

[Steve Scheifler]

I assume you have been consistent in whether or not suspension was loaded when tightening bushing bolts.

I don't assume equal collar height is a reliable way to make it level F/R, but should be very close L/R if weight is evenly distributed. 100# does seem like a lot. Try running a straight edge between the front scales and measure from that to the center of the lower arm from bolt. That's what I've used in the past as a second check, but you need to be very accurate since they aren't very far apart.

[Steve Scheifler]

In the rear of the FSM Body section there are two dimensioned sheets, one sheet for horizontal and one sheet for vertical dimensions. No tolerances included.

Ha! Embarrassed to admit I hadn't noticed and didn't look. Thanks David!