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I'm trying to set up for DOT true street tires. I managed a 1.2 60 ft time on a 295 55 15 radial, but as soon as I was out a little and boost ramped up the tires shook really bad.

These are new tires so I have not played with pressure. I just set them at 14 until things are worked out.

Is this because I had to run my rear shocks loose to get the tires planted hard? What do people do, stiffen the shock to control hop and reduce the trans brake boost??

I have rear single adjustable Strange. Do I need to dump them for DA?
 

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Put some more air in the tires first and foremost. 14psi is way low for radials. Start around 17psi. Rear shocks definitely don't need to be full loose either. Put about 5 or 6 clicks in the rears to start. You will probably want them even tighter, but see where those two changes put you and then adjust from there.
 

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Discussion Starter #4
Which drag radials? The new SS tire?
Yes. I have the 3454 P295/55R15's

I'm good as gold with settings now. My tires like 14-15 psi just fine. I did not try below 14, but they have no sign of sidewall distortion or wadding at 14. They have a clean hit and slightly flatten the sidewalls. 60's dropped at 16 psi even when they do not break into smoke.

My rear shocks just needed to be moved up one click tighter and the tire shake goes away.

They do reliable mid 1.2 60 ft with boost pulled back to 10 psi and then ramped in. This is on par with slicks at that boost and ramp. I did not try to push boost up yet. Slicks go 1.15 60 at 18 psi ramped to 25 psi in low.

Next race I will try less than 14 and try more boost. I'm not sure what they will hold.

I blasted the rims inside with a coarse grit for tooth. They only moved about 1/2 inch on the rims after 4 rounds. I did not glue them. But the hit was softer than normal.

All these runs in True Street were at 14 psi air.

https://www.youtube.com/watch?v=30t-h2gLHFI
 

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Nice!! I was looking into running that tire for Drag Week since it looks more rain friendly than my pros but haven't seen anybody post results. Do you have any pics of the car with the tires on? Are you mini tubbed?
 

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Discussion Starter #6
Nice!! I was looking into running that tire for Drag Week since it looks more rain friendly than my pros but haven't seen anybody post results. Do you have any pics of the car with the tires on? Are you mini tubbed?
No pix. They fit fully inside my wheel wells. Not minitubbed, just BFH mods. Stock rear end width. 5.5 BS weld 10" rims. Good clearance with these. Next size up rubs.

My rear suspension separates about 1" on launch, but these would take about 1.5" collapse or more before rubbing.

I'm reasonably sure I can get these either into 1.1's or way bottom 1.2 60's. I just was running very conservative boost and boost ramp.

I did not have any time trial passes. I staged wrong in the only time trial, and that was early afternoon. I drove 25 miles and then we drew chips and raced. Naturally I drew the fastest car 1st round, and second fastest second round. LOL

3200 lbs and about 63% on the front.
 
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Car is running good Tom ;) Glad to see you put some of the high $$$ heavy hitters on the trailer:grin2:. Did you end up winning your class(hard to tell)? Hope to finish my shop soon..and get my junk together + down there. Looks like Twiggs was hooking pretty well. Buddy of mine owns the Green hatch at the 13:40-13:50 mark on the video & kept blowing the tires off when he went to 2nd..but he's good at pedaling ;) RP
 

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Car is running good Tom ;) Glad to see you put some of the high $$$ heavy hitters on the trailer:grin2:. Did you end up winning your class(hard to tell)? Hope to finish my shop soon..and get my junk together + down there. Looks like Twiggs was hooking pretty well. Buddy of mine owns the Green hatch at the 13:40-13:50 mark on the video & kept blowing the tires off when he went to 2nd..but he's good at pedaling ;) RP

I took home the money. :)

I drew allegedly the fastest car first round, and then second round I drew the second fastest car in the class. My luck was outstanding. I was hoping for a six second car so I could try a more aggressive launch without risk of losing.

I was real conservative on tune at the start. I had no real time trials, just one run where I broke in the new tires. So I kept launch and boost ramp very safe.

I found a little end piece of oil separator spreader ring on my drain plug, so I have to look at my rings. This motor has a 100 or 200 passes at 20-28 psi boost. Time to look inside.

I've got another engine to stick in. I have a 363 with Callies billet crank and Fox Lake stage 4 heads. Better heads, more compression, and much better rotating assembly. It will be a fast swap. I'm hoping to see if the head and compression combo is better. Similar cams.

It's a 10:1 compression, which I hope works OK with boost. My present engine is 8.5:1 or so. 8.5 compression is a real pig without a lot of boost and timing.
 

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No pix. They fit fully inside my wheel wells. Not minitubbed, just BFH mods. Stock rear end width. 5.5 BS weld 10" rims. Good clearance with these. Next size up rubs.

My rear suspension separates about 1" on launch, but these would take about 1.5" collapse or more before rubbing.

I'm reasonably sure I can get these either into 1.1's or way bottom 1.2 60's. I just was running very conservative boost and boost ramp.

I did not have any time trial passes. I staged wrong in the only time trial, and that was early afternoon. I drove 25 miles and then we drew chips and raced. Naturally I drew the fastest car 1st round, and second fastest second round. LOL

3200 lbs and about 63% on the front.
what rear shocks are you running? coilover set up or stock spring?
 
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