M&H Racemaster PSI?

[pacettr]

tried 18 and 16. 1.89 best 60'.

Should I go lower?

275/45 18 DR

 

[TexasKyle]

I'm guessing they spun on you? You're probably pushing more power than me, with that 3.2 pulley. Just me personally, I probably wouldn't want to go lower than 14psi, but that might just be me.

 

[pacettr]

I'm guessing they spun on you? You're probably pushing more power than me, with that 3.2 pulley. Just me personally, I probably wouldn't want to go lower than 14psi, but that might just be me.

Actually just installed a 3.0.


Dropped to 15 and pulled a 1.834 on a new personal best of 11.477 @ 119.12

 

[Hawgman]

Basically what you need to do is find the sweet spot where they no longer spin. Sounds simple enough I know.. but it is different for everyone and no one is going to be able to tell you where you need to be with your car. They can only give you a general idea based on tire size and rear wheel horsepower. Pick a starting place with air pressure, go launch. If you don't spin, raise it 1psi. If you do spin, drop it 1psi. Just keep going until you find that "sweet spot" for your car.

I don't have any problem cutting low 1.7s at 18 psi with 285/60-15s

 

[pacettr]

Basically what you need to do is find the sweet spot where they no longer spin. Sounds simple enough I know.. but it is different for everyone and no one is going to be able to tell you where you need to be with your car. They can only give you a general idea based on tire size and rear wheel horsepower. Pick a starting place with air pressure, go launch. If you don't spin, raise it 1psi. If you do spin, drop it 1psi. Just keep going until you find that "sweet spot" for your car.

I don't have any problem cutting low 1.7s at 18 psi with 285/60-15s

That's ALOT more sidewall than I have.


My main concern is that I didn't want to go TOO low. I made two passes at 15 psi and pulled a 1.821 and a 1.834. Was hoping for high 60's-low 70's. I'm not the most experienced driver either.

 

[Hawgman]

My main concern is that I didn't want to go TOO low. I made two passes at 15 psi and pulled a 1.821 and a 1.834. Was hoping for high 60's-low 70's. I'm not the most experienced driver either.

If you're not spinning, bump it up a pound at a time (or hell, even a half pound if you have a good digital gauge and want to be that picky). Once you find the right pressure (basically 1 psi below where you spin) then the rest is just going to be practice and technique. All the tire in the world isn't going to make up for practice.

 

[stkjock]

How were you launching?? slipping the clutch or dump? did the tires spin? motor bog?

 

[pacettr]

How were you launching?? slipping the clutch or dump? did the tires spin? motor bog?

~4k-ish dump. The new clutch lets out very high and I'm not used to it yet. I didn't have anyone spotting, but it felt like it spun a bit.

 

[stkjock]

maybe try some higher revs?

 

[pacettr]

maybe try some higher revs?

with it spinning?

 

[stkjock]

well you seemed unsure if it was spinning.......... so if your are then no more RPM

 

[frarmar]

I cut a 1.7 with about 21 psi launching at about 3000 on my last trip to the track. Same tire you have.

 

[Tommygun]

20lbs and 3500 launch