2500HD 1/4 mile times

N900WM · July 21, 2003

03 2500HD extended cab short box 4x4 8.1L/Allison & 4.10LS gears, 285 REVO's with aluminium wheels. Only modes include a Volant intake with a 3.5inch cold air tube run to lower air dam.

Truck weight is 6455lbs. with full fuel and driver.

Used GTech.

All numbers corrected to Standard conditions.

Before:

0-60 time = 8.59 seconds

1/4 mile: 16.66 seconds @ 84.69 mph

Est. H.P. = 276

After Westers install and 200 miles of "break-in"

0-60 time = 7.5 seconds

1/4 mile: 15.74 seconds @ 91.24mph

Est. H.P. = 327

It's important to note that with the stock computer the off line acceleration was easy. Just mash the throttle and go. Not tire spin noted.

After the Westers computer was installed, I had to develope some technique off the line as the tire spin was slowing down the the times. The runs were close to the same conditions on a dry runway at 920ft. above sea level. These numbers represent the best of three runs.

This equates to an est. gain of 51h.p., 1.09 second gain on 0-60, .92 second gain on 1/4 mile with a 6.55 mph incease.

Thus far in the 200 miles I've driven, the mileage has increased by 1.2mpg. And I've been working it pretty hard!

This has mod ovbiously woke this truck up! I like it ALOT!

MarkD · July 21, 2003

Congrats! sounds like you made some good gains!

greyghost03 · July 21, 2003

Sounds like the Westers is worth it to me!

ShortCrew · July 21, 2003

Very nice numbers. That thing is really moving out!

I'll be purchasing a Wester's once I get about 1000 miles on my truck. I'm curious, how hard is it to remove the PCM? Its in a weird spot and I'm not quite sure how you remove the paneling that covers it? Is it a pretty easy R&R?

Thanks

N900WM · July 21, 2003

Actually ShortCrew,

The 6.0 and the 5.3 have enough room to make it easy. 5 or 10 minutes, no problem.

But the 8.1 is a bit of a struggle. It sits so close to the radiator and shroud that there's not much room to work in. And the upper radiator hose sits right on top of it.

If you look at the top of the computer cover there is a small slit just big enough to fit a small flat bade screwstick into. A little pry and it pops loose. But you'll have to wrestle the radiator hose out of the way to get the cover and the ECU out.

I would recommend you let the truck get good and cool before you do it. Don't be in a hurry if the engine is hot. Otherwise you arms will look like mine!

422 SS · July 22, 2003

Nice improvement.However their is no way you picked up 51 hp from a programmer on a gas pickup.I drag race alot(see sig) and a G-tech is horribly inaccurate.If you want an accurate test take your truck to a track and run it back to back.First run without the programmer 2nd with it.Try launching your truck in 4-hi and hitting the 2-hi button about 200ft down track.This technique will net your best times.Last friday I went [email protected] in my 7300 lb cclb 4x4 Duramax Ally with 33 inch rubber on a 2.08 60 ft.Only mods are Edge Hot Juice and Amsoil drop-in air filter.I think you will find G-tech is very optimistic.With my camaro it was 8mph and 5 tenths on the high side.Its good to see Im not the only one making a big 4x4 go fast.

N900WM · July 22, 2003

I hear ya on the H.P. numbers.

The GTech actually read 55h.p. The 51h.p. figure was calculated using Westers Weight and ET calculations.

I did not run a base line dyno run on this truck so I'll never know for sure.

Nice numbers on that big DMax!

ShortCrew · July 22, 2003

I agree that a G-Tech is not a replacement for a 1/4 mile track, BUT....I would think it would be accurate for testing changes. I've read many posts that show the G-Tech very accurate as far as repeatability. If you do 3 or 4 runs and it gives you the same numbers time and time again, then it should be a very accurate tool for measuring the performance gain of mods.

Professor · July 22, 2003

Try this Video link: Dmax going 14.46

Video

MarkD · July 22, 2003

I agree that a G-Tech is not a replacement for a 1/4 mile track, BUT....I would think it would be accurate for testing changes. I've read many posts that show the G-Tech very accurate as far as repeatability. If you do 3 or 4 runs and it gives you the same numbers time and time again, then it should be a very accurate tool for measuring the performance gain of mods.

I too, have complete faith in the g-tech. I have had one for years, and duplicated the results time and time again on a 1/4 mile track.

My 1/4 times were always .1 to .3 seconds better than indicated by the g-tech. In 4 different cars.

My 1/4 trap speeds were 1 to 3 mph lower on the track than the g-tech. I have read that this is to be expected due to the fact that the g-tech reads speed at the end of the 1/4, and the track averages the last 60 feet.