Feb 24th Famoso Results

Trainman

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Trainman
VIPER POWERED Join Date: Jun 2006
Location: Bakersfield, Ca
Posts: 1,534
Member #312
Trainman's Garage



Made two passes, not bad but not great either. I think I have an issue, I'll explain in a minute. My two passes were as follows:
Run 1: 1.667 60', 1/8th 7.533 @ 93.84, 1/4 mile 11.775 @ 116.80.
Run 2: 1.660 60', 1/8th 7.552 @ 92.62, 1/4 mile 11.826 @ 116.16.

Here's the issue I'm having and it started last time out (Feb 9th, all 5 runs) the truck is starting to SCARE me on the high end and each shift. It is starting to "walk around" or drift all over the track, especially in 4th gear, sort of like wanting to fishtail all over the place. The truck wants to nosedive to the left and the rear end wants to come around to the right, also the truck is pulling to the right. It has been very nerve racking to stay in the throttle at 117 mph, and then when I let off to shut down, I almost loose control, again the tail wants to walk around me on the right side. I talked with Brad today and we think it might be an issue with the rear end, Something broken and not delivering power to each wheel equally? What do some of you experts think could be going on. I need to solve this before adding another 200 rwhp with my engine build. The truck is an 04, could I need a front end rebuild? It has 67,000 miles. I think I'll have someone look into the rear end (spider gears, clutches, etc.). I've noticed my times are about .1 to .2 slower and my MPH is off by about 1.5 to 2 mph. The last time I lost speed the spider gears were broken, costing me about 20 rwhp (we discovered that on the DC Performance dyno). But I didn't have handling issues at that time. Any input is appreciated.

I also had fun driving the Black Camaro again. The owner rebuilt the engine, upgraded the rear to ZL1 3.73 gears and had some MT ET street radials. When I got there I saw him run an 11.59 @127 (last time on street tires he ran 12.49 @119). He saw me and said "my driver mod is here" and asked me to take a run in the car. OK , the car felt real smooth and not that fast at all.....but the time slip said different....I ran a 10.74 @ 134.78mph.....wow. Nice.

I also had a younger kid with a supercharged 6.1 Challenger ask me to drive his car. He had Nitto radials, said it was bogging bad @ 2500 rpm , I also asked him about the tune, max hp dyno rpm, redline (he thought it was 6400-6500). Well I didn't run very well, I tried to do a 2nd gear burnout and the car stalled twice, I left the line @ 3000 and it wheel-hopped bad all the way through 1st (spinning) , the rev limiter was about 6250 so I hit the rev limiter twice during the run (in 1st and 2nd), so the car went 13.17 @ 116+. I wasn't very proud of myself, but the car was very different and hard to drive. With a little more seat time I could probably put the car in the 11's. I told the owner he first needs to cure the wheel hop issues and get some better tires (Nitto's suck). He also needs to strengthen the stock axles and add a Line-Loc.

Pretty fun and scary day to say the least. Those runs will probably be on video. Thanks again Brad!
 
Thanks again Jerry for covering my expenses and just being a good friend. The video is the least I can do. Lets figure out what the issue is with your truck first. I will start by uploading the video of your runs to review the issue in the next few days. It will only be the raw video. The edited video will come later.
 
Trainman
VIPER POWERED Join Date: Jun 2006
Location: Bakersfield, Ca
Posts: 1,534
Member #312
Trainman's Garage



Made two passes, not bad but not great either. I think I have an issue, I'll explain in a minute. My two passes were as follows:
Run 1: 1.667 60', 1/8th 7.533 @ 93.84, 1/4 mile 11.775 @ 116.80.
Run 2: 1.660 60', 1/8th 7.552 @ 92.62, 1/4 mile 11.826 @ 116.16.

Here's the issue I'm having and it started last time out (Feb 9th, all 5 runs) the truck is starting to SCARE me on the high end and each shift. It is starting to "walk around" or drift all over the track, especially in 4th gear, sort of like wanting to fishtail all over the place. The truck wants to nosedive to the left and the rear end wants to come around to the right, also the truck is pulling to the right. It has been very nerve racking to stay in the throttle at 117 mph, and then when I let off to shut down, I almost loose control, again the tail wants to walk around me on the right side. I talked with Brad today and we think it might be an issue with the rear end, Something broken and not delivering power to each wheel equally? What do some of you experts think could be going on. I need to solve this before adding another 200 rwhp with my engine build. The truck is an 04, could I need a front end rebuild? It has 67,000 miles. I think I'll have someone look into the rear end (spider gears, clutches, etc.). I've noticed my times are about .1 to .2 slower and my MPH is off by about 1.5 to 2 mph. The last time I lost speed the spider gears were broken, costing me about 20 rwhp (we discovered that on the DC Performance dyno). But I didn't have handling issues at that time. Any input is appreciated.

I also had fun driving the Black Camaro again. The owner rebuilt the engine, upgraded the rear to ZL1 3.73 gears and had some MT ET street radials. When I got there I saw him run an 11.59 @127 (last time on street tires he ran 12.49 @119). He saw me and said "my driver mod is here" and asked me to take a run in the car. OK , the car felt real smooth and not that fast at all.....but the time slip said different....I ran a 10.74 @ 134.78mph.....wow. Nice.

I also had a younger kid with a supercharged 6.1 Challenger ask me to drive his car. He had Nitto radials, said it was bogging bad @ 2500 rpm , I also asked him about the tune, max hp dyno rpm, redline (he thought it was 6400-6500). Well I didn't run very well, I tried to do a 2nd gear burnout and the car stalled twice, I left the line @ 3000 and it wheel-hopped bad all the way through 1st (spinning) , the rev limiter was about 6250 so I hit the rev limiter twice during the run (in 1st and 2nd), so the car went 13.17 @ 116+. I wasn't very proud of myself, but the car was very different and hard to drive. With a little more seat time I could probably put the car in the 11's. I told the owner he first needs to cure the wheel hop issues and get some better tires (Nitto's suck). He also needs to strengthen the stock axles and add a Line-Loc.

Pretty fun and scary day to say the least. Those runs will probably be on video. Thanks again Brad!

I agree Trainman and mine has done it before as well but kinda think some has to do with radial fronts and bias ply rears which has new. A no - no for decades, lol. I do feel as much as we run ours at the track and as awesome and bitch free our rear ends have been, they deserve internal attention.Clutch packs, new spiders if needed, bearings, seals, etc. I think a good locker/posi unit would be a great investment! We kinda think Justin's may be similar as well. Watch my last set if vids against GTR, Cobalt, and solo run and watch her walk between shifts. Also as you noted our suspensions up front are being extended and compressed to their limits especially at launch and 1-2 shift:burnout: Not unlike a car that gets too much air and the driver releases the gas or brakes too hard, slamming the front into the ground, compressing entire front suspension, and if they're lucky only threw off alignment (camber)
Ours is less of this analogy but I think you understand my theory. The front end simply takes a fast extension on launch followed by a fast compression/extension during 1-2 shift (other gears not as drastic)
Shocks internally busted? There are a few things that lead to our trucks being squirrelly, lol. Gotta find mine as well but in thinking shocks on mine as well as alignment possibly. Hope my jibberish makes some kinda sense, haha. :D
 
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Your problem does sound similar to mine. I've lost MPH but my times still improved, running in better air and had better 60's. Have you had any abnormally bad 60's at all? Mine seemed to happen a while back at the track it just spun 1 tire in the burnout then launched real bad(1.77 if I remember right), next pass I dropped the clutch harder for my burnout and it spun both tires and hooked like it should but my mph dropped to 109mph. Pulled the diff cover and found that the passenger side clutch pack in the limited slip had broken its retainer clips and started to spin in the carrier. That along with the stiff side wall of your front tires my be adding to your handling problem.
 
I agree Trainman and mine has done it before as well but kinda think some has to do with radial fronts and bias ply rears which has new. A no - no for decades, lol. I do feel as much as we run ours at the track and as awesome and bitch free our rear ends have been, they deserve internal attention.Clutch packs, new spiders if needed, bearings, seals, etc. I think a good locker/posi unit would be a great investment! We kinda think Justin's may be similar as well. Watch my last set if vids against GTR, Cobalt, and solo run and watch her walk between shifts. Also as you noted our suspensions up front are being extended and compressed to their limits especially at launch and 1-2 shift:burnout: Not unlike a car that gets too much air and the driver releases the gas or brakes too hard, slamming the front into the ground, compressing entire front suspension, and if they're lucky only threw off alignment (camber)
Ours is less of this analogy but I think you understand my theory. The front end simply takes a fast extension on launch followed by a fast compression/extension during 1-2 shift (other gears not as drastic)
Shocks internally busted? There are a few things that lead to our trucks being squirrelly, lol. Gotta find mine as well but in thinking shocks on mine as well as alignment possibly. Hope my jibberish makes some kinda sense, haha. :D

I was concerned about radials in front and bias ply slicks in back, because I had heard the same thing "don't mix" , but the only tire that would fit the 18" Bogarts in front was the radial tire. The first time ever with that set-up was last Jan at Speedworld in Phoenix (Jan 2012). The truck was fine, no handling issues at all, and on through the rest of 2012 ( even my best day with 5 runs in the 11.60's) on through Nov 9th 2012 Test and Tune. After I got new rear street tires, (sometime in December) I started noticing handling problems accelerating onto a freeway at speeds above 60mph (rearend getting squirrelly) but didn't think much of it. This last two times at Famoso have been very scary.
 
Your problem does sound similar to mine. I've lost MPH but my times still improved, running in better air and had better 60's. Have you had any abnormally bad 60's at all? Mine seemed to happen a while back at the track it just spun 1 tire in the burnout then launched real bad(1.77 if I remember right), next pass I dropped the clutch harder for my burnout and it spun both tires and hooked like it should but my mph dropped to 109mph. Pulled the diff cover and found that the passenger side clutch pack in the limited slip had broken its retainer clips and started to spin in the carrier. That along with the stiff side wall of your front tires my be adding to your handling problem.

60' times have been OK, low 1.60's up to 1.66, so not too bad. I think I'll start with looking into the rear end clutch packs and spider gears. I'm wondering if there is a better positraction set-up that is stronger than the factory and still streetable?
 
mine had a similar issue and we found the rear end needed to be rebuilt... gears were fine, because we caught it early... clutch packs and such needed to be replaced...

Were you having handling issues at the 1/4 mile on the high end?
 
Clutch packs on mine were bad, I had similar issues with truck on the top end. That's when I went ahead and put in the 4.88's and had everything redone.
 
I'm uploading Jerry's last run from yesterday. It is just the raw video to see if we can see what Jerry is talking about. The computer says the upload will finish in 80 min from now. It will be on my "dragracing505" youtube channel.
 
Ok it looks like its not reacting right on passenger front spring/shock to me. Could just be angle of video? What does a visual of your front camber look like?
Do you always do burnouts in the water box?? That tends to throw more water into your wheelwells to drip back on your tires on the line! :burnout:
Don't know why I'm telling this to the fastest NA RC out there, but my .02 from this vid. Looked like even the crew at the burnout box was trying to wave you forward?
I do share the wiggle you speak of though seriously, watch my solo run in the racing section.
I really see it being the clutch packs slipping and transferring power side to side down the 1320. Or drops of water falling off the wheelwells through the run doing similar?
Trying to narrow it Down myself but we are propelling tons at high velocity!!
 
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My last time at the track, I noticed the one wheel wonder burnout if I didn't drop the clutch hard as well. Gonna have to go in the rear I think and check out my clutch packs as well. I didn't notice so much of a loss at the end of the track, but I have noticed if coming out of a corner on the street and getting on it a bit, it gets squirrley then, and I don't mean tires spinning out from behind me...definitely interested in what you guys find out as well!
 

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