It Bogs or Spins

Turbotungsten

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I took my car to Gateway Friday night. Its a 281CID 70mm single turboed manual trans, full weight car on MT ET Street Radial (265/40 18s). I ran it on 93 octane. I ran 15PSI boost, 13 degrees timing and 10.9 AFR.

My best run was launching with 2 step at 3400rpm. I still bogged with 60ft at 2.02 this was an 11.66 at 127.35mph.

I tried increasing my launch rpm, but any more and i was really building boost, so it just spun badly.

Honestly I was hoping to run 1.60s on 60ft and get into the 10's. As you can tell from my trap speed, I have plenty of power to do that.

I have ran 1.92 60ft without a 2 step, and was really hoping that my new WOT box/2step would seriously decrease my 60ft times.

I said all of that for this....Am I not going to be able to go quicker with these tires? If not, what do you guys recommend? ET Street (Bias)?

Any tips would be helpful.
 

JUSTA3V

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And seat time. There is no mod or setting to get you there. Practice and adjust.

ask me how I know.
 

Turbotungsten

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Suspension is BMR upper and lowers, subframe connectors, front antisway bar is removed, roush springs, stock shocks/struts. I am sure shocks/struts would help with transfer...and of course, more seat time will do some good.
 

stkjock

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I took my car to Gateway Friday night. Its a 281CID 70mm single turboed manual trans, full weight car on MT ET Street Radial (265/40 18s). I ran it on 93 octane. I ran 15PSI boost, 13 degrees timing and 10.9 AFR.

My best run was launching with 2 step at 3400rpm. I still bogged with 60ft at 2.02 this was an 11.66 at 127.35mph.

I tried increasing my launch rpm, but any more and i was really building boost, so it just spun badly.

Honestly I was hoping to run 1.60s on 60ft and get into the 10's. As you can tell from my trap speed, I have plenty of power to do that.

I have ran 1.92 60ft without a 2 step, and was really hoping that my new WOT box/2step would seriously decrease my 60ft times.

I said all of that for this....Am I not going to be able to go quicker with these tires? If not, what do you guys recommend? ET Street (Bias)?

Any tips would be helpful.

What tires are you on?
:whistle1:


how are you doing your burnout?

how are you launching - drop or slip of the clutch?

what's the rear gear?

those tires are capable of 1.6s - I had them and pulled those 60's
 

Marble

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Stkjock has the right questions.

My thought is you're trying to get that tire to work like a race tire and it can, is just tough. That's why a lot of guys go to some type of 15x10 wheel and good tire. I prefer the bias ply but that's just me.

Basic suspension mods in the rear can get it down to 1.6. With adjustable shocks, Eibach pros, lca arms relocated and several different types of tires I was down in the 1.5 range. That was a single turbo of ofa two step also.

I have that same combo now only with a transbrake and normally get into the high 1.4 range.

I think a real tire, proper burn out, minor suspension changes and you'll see a big difference. And a little seat time to know what to adjust...
 

redfirepearlgt

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:whistle1:


how are you doing your burnout?

how are you launching - drop or slip of the clutch?

what's the rear gear?

those tires are capable of 1.6s - I had them and pulled those 60's

^^^ LOL wasn't exactly on my A-game yesterday obviously.
Missed that as I was in the prep phase (fasting and prep kit that gives you the trots like Sea Biscuit) for today's colonoscopy.

OP with the kind of power you are putting down I would reconsider looking at a bias ply setup as RocketcarX suggested. The added BMR drag springs will help you as well. I run them also. Marble also mentioned relocation brackets which are also nice as well as some adjustable rear shocks. I ran a 17" MT ET Street II series DR (no longer made) on my 13 stick shift with Roush springs (not my first choice but they were cheap) and BMR UCA/LCA's and relo's and cut 1.7's on them leaving at 4000 RPM. Had I stayed with ha stick shift car I would have gone to a bias ply as has been mentioned.

Seat time will be the biggest help with a stick shift car. Best of luck. Glad we figured out your tune issue as well. :clap:
 

Smalls5oh

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Do you have a boost controller on the car? I was thinking you could leave at the higher rpm, slip the clutch, and let the boost controller ramp it in.

Did you notice any of the faster drag radial cars having any trouble? Gateway has been horrible for prep lately on the regular Test and Tune/Bracket nights.
 

slow06stang

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I would say everyone else has covered the good stuff.

Do you have a boost controller on the car? I was thinking you could leave at the higher rpm, slip the clutch, and let the boost controller ramp it in.

Did you notice any of the faster drag radial cars having any trouble? Gateway has been horrible for prep lately on the regular Test and Tune/Bracket nights.


I have heard the prep has beenhorrible from other people as well.
 

JeremyH

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I took my car to Gateway Friday night. Its a 281CID 70mm single turboed manual trans, full weight car on MT ET Street Radial (265/40 18s). I ran it on 93 octane. I ran 15PSI boost, 13 degrees timing and 10.9 AFR.

My best run was launching with 2 step at 3400rpm. I still bogged with 60ft at 2.02 this was an 11.66 at 127.35mph.

I tried increasing my launch rpm, but any more and i was really building boost, so it just spun badly.

Honestly I was hoping to run 1.60s on 60ft and get into the 10's. As you can tell from my trap speed, I have plenty of power to do that.

I have ran 1.92 60ft without a 2 step, and was really hoping that my new WOT box/2step would seriously decrease my 60ft times.

I said all of that for this....Am I not going to be able to go quicker with these tires? If not, what do you guys recommend? ET Street (Bias)?

Any tips would be helpful.


This sounds all to familiar. I experienced the same thing bogs or spins. My best ever run at 12psi was 11.7 @ 125 which was around 550rwhp on my setup. No matter what I tried I couldn't get my 60fts better than 1.9 to 2.1 sec area.

With the wot box I was able to get it down to 1.8 sec after a lot of trial and error. It boiled down to less air in the tires, longer second gear burn out and and around 4800 rpm on the 2step 4-6psi at launch. They key is get rid of the bog and dont just dump the clutch at the higher rpm and boost launches. I had to force my self to slow down the clutch release to stop the spin.

From there I felt for my setup that was about the best I was going to get with the car on low gearing/ tall tire/ 4k lb car and a stick with a street suspension setup. I'm sure a better driver could do better as well.
 

ponys197

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My pit partner at Route 66 this last NMRA event had a 2007 GT/CS with an On3 76mm turbo , 4R70W trans on MT drag slicks - 15x10's running on 12psi of boost. When he made his 1st runs he was at 11.9's and 1.9 60ft's. I got him to do a better burnout and leave about 2200rpm's on footbraking because he was running SST and his best run of the weekend was an 11.3 on a 1.7ish 60ft. He had UPR LCA's / UCA and adjustable drag shocks.

Advised him to get a line lock so he could do a better burn out and to get a rebuild on the rearend with Cobra clutch's as he had slop and 1 wheel peel at times.
 

NUTCASE

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I have had a few cars with the bog or spin issue. The best solution I have found is to both improve traction through gears and suspension AND to gear down with deeper gears and a looser converter if you have an auto.


the suspension + tires need to be improved obviously because you are spinning, however the bog/spin mentality is also from to tall gears. taller gears bog you, but they will also make you spin more because when traction is broken your engine can spin the tires to a higher speed.
 

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