Need some Chassis Suggestions

Dave Steltz · 05-08-2011, 05:11 PM

Got my car back on the track (after a wreck last year) this weekend and had some issues..

Made 6 passes total (between sat and sun), all in the right lane...I know the track was fine for 5 of them, as other cars just as fast or faster than mine had no issues..

About 250-300 feet into the run, on 3 of the 5 runs, the rear came out from under the car, and kicked to the right, which made the car go left...

Today the first run was 8.76, with a 1.231 60 ft and went straight down...Second run same 60' (1.232) and not much after the 1-2 shift the rear got lost and had to abort...Third run same 60 again (1.231) and it got loose , but not as bad, and then went down the track..
After the 330 or so it on rails..

So I dont think its the alignment or anything, and its pretty much ok at the launch, but not in control at all at 300 feet...

One thing I'm not sure of , is where the pre-load is, when I had it on the alignment machine I moved the rear a small amout, (it was a little cocked) and I'm not sure that I reset the pre-load to where it was..

So any and all suggestions are welcome...

Tom Goldman · 05-09-2011, 08:46 AM

Dave , if the car is launching and going straight up untill the shift, the preload is probably in the ballpark.
I'd loosen the shock, both bump and rebound ,as it sounds like they are too stiff and the tires are breaking loose after the shift.
If your 4 link is set up short and violent for S/G, you may have to lenghten the intersection to run wide open.
If you're planning on running the MASGA race at Cecil, come and see me.
Or PM me if you're not.

krugracing12 · 05-16-2011, 10:10 AM

Dave,
There is a good size bump in that right lane in that area- 200-300 feet out. I see it on the graph and i think it is a little worse on the right side of the groove. I agree with Tom that softening the car up will help, but I would make a pass or 2 in the left lane I make any big changes.

Bill

Racer4077 · 05-27-2011, 01:55 PM

If its sticking on the launch with no problem and coming un-done at 300' or so, its more likely your shock settings. Sounds a little stiff to me. Bump and Rebound is a good place to start. A good shock with have a knob on the back of the shock ..... make adjustments from there.

SG1809 · 06-01-2011, 05:33 PM

Dave,

You hit hard with that accident, I would suggest to pull the rear shocks and compress them and make sure they are functioning properly. If they are then try loosening them like Tom said.
Regards,
Pat I.

Dave Steltz · 06-28-2011, 11:20 AM

Just an update, tried a couple of adjustments and didnt help...went back to the shop, checked all the suspension for any obvious issues (didnt find anything)..

Put 'er back on the scale, and found out that the dumb crew chief forgot to put the weight of the fat driver in the seat when setting it up....

Did that , re-adjusted, and guess what...problem solved...straight and true...

Thanks for all the suggestions...

05-08-2011, 05:11 PM	#1
Dave Steltz Member Join Date: Nov 2003 Posts: 323 Likes: 0 Liked 0 Times in 0 Posts	Need some Chassis Suggestions Got my car back on the track (after a wreck last year) this weekend and had some issues.. Made 6 passes total (between sat and sun), all in the right lane...I know the track was fine for 5 of them, as other cars just as fast or faster than mine had no issues.. About 250-300 feet into the run, on 3 of the 5 runs, the rear came out from under the car, and kicked to the right, which made the car go left... Today the first run was 8.76, with a 1.231 60 ft and went straight down...Second run same 60' (1.232) and not much after the 1-2 shift the rear got lost and had to abort...Third run same 60 again (1.231) and it got loose , but not as bad, and then went down the track.. After the 330 or so it on rails.. So I dont think its the alignment or anything, and its pretty much ok at the launch, but not in control at all at 300 feet... One thing I'm not sure of , is where the pre-load is, when I had it on the alignment machine I moved the rear a small amout, (it was a little cocked) and I'm not sure that I reset the pre-load to where it was.. So any and all suggestions are welcome... __________________ Dave Steltz 135G SG/SP/SST BIAECH Racing Team Last edited by Dave Steltz; 05-08-2011 at 05:14 PM. Reason: re-word

05-09-2011, 08:46 AM	#2
Tom Goldman VIP Member Join Date: Jan 2003 Location: Allentown,PA Posts: 2,477 Likes: 892 Liked 883 Times in 237 Posts	Re: Need some Chassis Suggestions Dave , if the car is launching and going straight up untill the shift, the preload is probably in the ballpark. I'd loosen the shock, both bump and rebound ,as it sounds like they are too stiff and the tires are breaking loose after the shift. If your 4 link is set up short and violent for S/G, you may have to lenghten the intersection to run wide open. If you're planning on running the MASGA race at Cecil, come and see me. Or PM me if you're not. __________________ Tom Goldman 1500 SG , 1506 STK

05-16-2011, 10:10 AM	#3
krugracing12 Member Join Date: Dec 2006 Posts: 171 Likes: 0 Liked 0 Times in 0 Posts	Re: Need some Chassis Suggestions Dave, There is a good size bump in that right lane in that area- 200-300 feet out. I see it on the graph and i think it is a little worse on the right side of the groove. I agree with Tom that softening the car up will help, but I would make a pass or 2 in the left lane I make any big changes. Bill

05-27-2011, 01:55 PM	#4
Racer4077 Junior Member Join Date: Mar 2011 Location: Midland, TX Posts: 12 Likes: 0 Liked 0 Times in 0 Posts	Re: Need some Chassis Suggestions If its sticking on the launch with no problem and coming un-done at 300' or so, its more likely your shock settings. Sounds a little stiff to me. Bump and Rebound is a good place to start. A good shock with have a knob on the back of the shock ..... make adjustments from there.

06-01-2011, 05:33 PM	#5
SG1809 Member Join Date: Sep 2005 Location: Monroeville, NJ Posts: 119 Likes: 0 Liked 0 Times in 0 Posts	Re: Need some Chassis Suggestions Dave, You hit hard with that accident, I would suggest to pull the rear shocks and compress them and make sure they are functioning properly. If they are then try loosening them like Tom said. Regards, Pat I.

06-28-2011, 11:20 AM	#6
Dave Steltz Member Join Date: Nov 2003 Posts: 323 Likes: 0 Liked 0 Times in 0 Posts	Re: Need some Chassis Suggestions Just an update, tried a couple of adjustments and didnt help...went back to the shop, checked all the suspension for any obvious issues (didnt find anything).. Put 'er back on the scale, and found out that the dumb crew chief forgot to put the weight of the fat driver in the seat when setting it up.... Did that , re-adjusted, and guess what...problem solved...straight and true... Thanks for all the suggestions... __________________ Dave Steltz 135G SG/SP/SST BIAECH Racing Team