Starting to Learn on 95 G30 5.7 for Towing

[donf]

The exhaust has been replaced before I owned the van. Typical muffler shop work with crush bends and globed mig welds. I am sure there is a bit of power to be had there, but its quiet and not rusty. The cat is an aftermarket 3".

[Fast355]

The exhaust has been replaced before I owned the van. Typical muffler shop work with crush bends and globed mig welds. I am sure there is a bit of power to be had there, but its quiet and not rusty. The cat is an aftermarket 3".

That is good news atleast. i could only imagine how bad it would be with the stock exhaust. Thankfully my 83 never had that stupid cat. Came from GM with the tubular stainless manifolds and true duals they built some of them with but GM sucked the life out of it with twin smog pumps.

[Fast355]

I could only imagine how poorly that setup towed any real weight with the 3.23 gears.

I found my Express van marginal with 3.73 gears and the 4L85E. That was with a 300 hp Marine Vortec 350 setup making ALOT more HP/TQ.

At the wheels it made
170 hp @ 3,000
205 hp @ 3,500
225 hp @ 4,000
230 hp @ 4,500

Torque started out in the 280 range, peaked at 303 @ 3,400 but took a nose dive above 4,000 rpm.

[donf]

The dyno and trailer are slightly under 5000 lbs so its OK now. It will not win any races, but I can do the speed limit. I do want to do some work to the engine, but any major projects have to wait until winter as this is my only tow vehicle and the dyno has been going out almost every weekend lately. It slows down though when the weather gets cruddy again.

I downloaded the "BJLH 94 C-K Truck 5.7TBI 4l60e with 3.73 or 3.42 gears" bin this morning, to do the same to that bin. The timing tables are exactly the same as my G30. Has anyone read a hypertech or jet tbi chip and saved the bin file? I was just curious to snoop through one and see what changes they made compared to a factory chip.

[Fast355]

The dyno and trailer are slightly under 5000 lbs so its OK now. It will not win any races, but I can do the speed limit. I do want to do some work to the engine, but any major projects have to wait until winter as this is my only tow vehicle and the dyno has been going out almost every weekend lately. It slows down though when the weather gets cruddy again.

I downloaded the "BJLH 94 C-K Truck 5.7TBI 4l60e with 3.73 or 3.42 gears" bin this morning, to do the same to that bin. The timing tables are exactly the same as my G30. Has anyone read a hypertech or jet tbi chip and saved the bin file? I was just curious to snoop through one and see what changes they made compared to a factory chip.

For emissions compliance those chips only have extra timing added at WOT and only in the 90 KPA plus areas. Someone running around at 5K elevation would not see any difference at all.

I think I uploaded a modified BJYN bin file years ago on here that had my timing map I ran when I had stock heads and stock cam.

[donf]

Thanks for the tips. I did a fast search using your username and BJYN and found nothing. No worries, It was mostly for curiosity. I dont think I will mess with a lot until I swap the cam and pull the heads once things slow up anyway.

[donf]

I took the dyno out again today. It was a slow day, only three cars, but the van seems to be doing a little better with the new chip I burned. I was still very conservative with the timing table and PE, just made a few small changes. I have not run the van on the dyno again but here is a picture of one of the cars we did today, nothing computer controlled on it, but it squeezed out 520 hp. I thought it was cool.