Starting to Learn on 95 G30 5.7 for Towing

[donf]

I agree it needs help. I try not to get into the number games. These were weather corrected numbers with a true stock engine/stock tune and very repeatable. I can make the dyno spit out pretty much anything I want. That's what people don't understand. Dyno dynamics even has a "comparison" HP correction to compare to Dynojet, ect, but it's just not necessary.

[Fast355]

I agree it needs help. I try not to get into the number games. These were weather corrected numbers with a true stock engine/stock tune and very repeatable. I can make the dyno spit out pretty much anything I want. That's what people don't understand. Dyno dynamics even has a "comparison" HP correction to compare to Dynojet, ect, but it's just not necessary.

Was not a numbers game as much as just stating how badly those compnents combined with 87 octane based tune are holding it back. Just losing the factory cat and muffler is probably worth 15-20 HP with the OEM manifolds and Y-pipe in place. I have seen 30+ TQ gains through alot of the powerband with Timing/Fueling changes alone on a STOCK engine. Running 91+ octane fuel you can run 12-16* of advance at 1,200 rpm and 100 KPA and bring as much as 28* advance in by 2,800 rpm. Above 3,600 rpm you can bring it up to 32*. Compared to a factory GM van tune that goes negative on a WOT throttle hit from a dead stop and peaks out at 20-22* as late as 4,000 rpm, it makes a world of differenc. Especially combined with air/fuel ratios that approach 10:1 on the factory tune in places. Bypass the PE fuel delay and set the PE to deliver 12:1 AFR from 1,600-3,000 and taper off to 12.6 by 4,000. Finally set your stoichiometric AFR to 14.1 to compensate for E10 and dial in your VE tables.

[donf]

Thank you for the tips. The van has been towing the chassis dyno to events for a few months without missing a beat. I have had to manually shift from 3rd to 2nd more often than I like on hills, so I started to change a few kick down settings on the chip today. So far all I have adjusted has been shift points and lowered the temp for hot mode. I will mess with more as time allows.

[donf]

Here is the main spark table untouched from my bin. The light duty 95 G30 Bin has some changes over a lower GVW van. When I tried a G20 bin my shifts turned softer, even with the reworked transmission and there were other small changes I found too. I used my original bin for the base after that. Billy Graves helped me with transmission advice and I pretty much have the shift points dialed in. It made a big difference loaded and unloaded. The only real change to the power train so far is the 4.11 swap from 3.26. The van actually became useful after that for towing. I may try messing around with the van on the dyno to see what kind of improvements can be made, by just altering the spark table.

[Fast355]

Here is the main spark table untouched from my bin. The light duty 95 G30 Bin has some changes over a lower GVW van. When I tried a G20 bin my shifts turned softer, even with the reworked transmission and there were other small changes I found too. I used my original bin for the base after that. Billy Graves helped me with transmission advice and I pretty much have the shift points dialed in. It made a big difference loaded and unloaded. The only real change to the power train so far is the 4.11 swap from 3.26. The van actually became useful after that for towing. I may try messing around with the van on the dyno to see what kind of improvements can be made, by just altering the spark table.

Well that is a spark map I have not seen before. Compared to the G20 and 4l80E G30 map I have it looks like they combined half of each and gave your timing map.

There is a good amount of torque and hp to be made manipulating the timing, VE and command air/fuel ratio in these.

I am assuming your van has the GM pellet box cat still? If so they absolutely kill power and MPG.

[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.