I have a 2004.5 LLY Silverado with 3.73 i have only been racing 1/8th mile, i finally went to a 1/4 mile drag strip where i ran it for the first time. i was using 28 M/T cheater slicks. when i took my first run the truck hit the rev limiter around the 1000 foot mark so i back off the nos and the truck went by at 105. im thinking about getting the M and H 30 inch cheater slicks, but are 2 inches going to help me not hit the rev limiter at the top end? will two inches be enough. or do i need higher gears. and the truck was not runnign good because it did lose 3 mph on the 1/8 mile aong with 2 tenths and it did do a 13.15 with only a 1.971, it used to do mid-high 1.8 when the posi was slipping less. that truck should run 12.90's will 3.73 gears and a 30 inch tire be enough for that truck to hit 107- 108? maybe more?

Factory will shut you off at 98 or some were around there. Your going to need to blast the limiter with programing. What do you have?

you got a 4x4?

With 30" tires and a 3400 rev limiter you can hit 115
With 28" tires and a 3400 rev limiter you can hit 107

Thats weird i can only hit 105 on the 28 at 3400.. i see the rpm stop at 3400 why would it go by at 105 and not 107? would it have to do with the lower tire pressure being so low that the tire is shorter? or maybe it hit 107 and since the rev limiter bounced it back to 105? Any ideas?

And also was kind of ET would produce a speed of 115? i know my truck can run better then 105, my bottle presure was only in the 600's too, and my 1/8 mile was only a mid 8.50 where before it would be in the 30's with 2 1/2 more MPH in the 1/8th

those 28 arent gonna be 28 high with all that weight on em,i have a set to,you need some rpms,not sure were to get em from for the lly,

Thoughts:

105 vs. 107 is 2%, it could just be gauge error of the tach. Are you sure your engine redline is actually 3400?

Some of the error you see is called tire slip and it applies anytime a tire is under acceleration force. In the case of a pickup going 100+ mph, it's the wind loading. The rubber before it hits the ground is not stretched, yet the rubber on the ground is being stretched. Different tires have different amounts of slip as a function of torque being applied to them and the strength of the tread.

Combat slip by selecting a tire with more tread plies/strength. Even a tube will help. Increasing air pressure can help somewhat too.

But your real solution is the 30" tire. My truck did not go any quicker running 28" 's. Current thought is that the engine likes more load in first and second gear.

Just curious, what tuner you running? How big of a jet?

Those are darn good times for an lly.....I think those are the best yet.....Give us the low down on the programming!

MY truck Dynoed at 434 spining the 315's on the dyno, so i dont know if it would have been more with just the Hot accelerator and the Enforcer with a 5" exhaust. with that i ran 8.90's in the 1/8th And then added some nos ,the best jet it liked was .82 got me into the 8.40's then later i got the afe intake gave me a tenth when i dont use the nos, and about 1/2 when i do use it.



As for my RPM limiter im pretty sure it was 3400, but also i was running my tires at 13 pounds, the rim almost hits the ground when i launch, so im pretty sure that tire at 105 does not expand to 28 inches.

Damn. I couldn't get that stack to work predicably at the dragstrip. I dyno'd it on a Mustang at 404HP, but at the track, the Enforcer would not always hit in 5th gear.

I haven't had much luck with stacks yet. But I'm still trying. ;)

They work good with me. I'm also waiting for the Upgrades to come out. PPE told me that they are working on Upgrades for the lly xelerator and the Enforcer, but they are not sure how long they will take or when they will be out.

DO you guys know where i can get an lb7 turbo? bigger one would be better.

You have to allow for torque converter slip in your mph vs rpm. Also you get into tire growth and so on and so fourth. Anyway, the slip of the converter is throwing off the calculation. Unless you can get it to lock and hold under full throttle.

Convertor should be locked by the time you are in 5th.

Never paid attention on the diesel honestly, but under full throttle gassers and such will not lock the converter under full throttle. They always unlock when hitting the brakes or on acceleration.

They work good with me. I'm also waiting for the Upgrades to come out. PPE told me that they are working on Upgrades for the lly xelerator and the Enforcer, but they are not sure how long they will take or when they will be out.

DO you guys know where i can get an lb7 turbo? bigger one would be better.

Check Ebay for the LB7 turbo.

This is a quote out of the service manual for the converter. Like I said, I have never verified it, just took it as to work the same as any other and I have seen generic statements made by the manual.

"Important: The TCC will not engage until the engine is in closed loop operation. The vehicle must be in a near cruise condition, not accelerating or coasting, and on a level road surface."

The allison convertor locks up solid in 3rd 4th and 5th gear. Even full throttle runs. Run in T/H. Get a tech II or other scan tool to monitor it or just get an edge/attitude.

Will have to try this at work tomorrow with the Tech II, has me curious now...lol

I stand corrected, tested mine with the Tech II on the way home, pretty much any full throttle in 3rd up turned on the TTC. Guess thats what I get for thinking like a gas job...lol