Hi From New Zealand

[Kitch]

Hi,

I've played with carbed V8's for years and while I've had a few injected cars I've never really modified them.
I've now got a 94 G20 5.7 TBI Starcraft van and I've decided to have a go at tinkering with EFI, so I here at the steep part of the leaning curve.

Cheers.

[Fast355]

Hi,

I've played with carbed V8's for years and while I've had a few injected cars I've never really modified them.
I've now got a 94 G20 5.7 TBI Starcraft van and I've decided to have a go at tinkering with EFI, so I here at the steep part of the leaning curve.

Cheers.

That is one of the simplest forms of EFI and one of the best years for TBI as it has an electronically controlled transmission. Open up the exhaust with some headers and a nice exhaust, throw in a mild cam and roller rockers and open up the intake tract and it will run nice for you.

[Kitch]

Thanks for the advice :-)
My van seems to run fine around town but point it at a hill or try get it to go up a gentle incline in top gear and feels gutless, people have said to me it would be a cool van to take away and tow a race car behind it but I seriously doubt the vans ability to move anything other than it's self.
At this stage I've fitted a 3" single exhaust system and removed the CAT.
I've contemplated headers but weren't sure what ones were the best as far as fit goes, there seem to be a lot of nice headers avalible for C-K pickup trucks but I don't know if they will fit a G series van.

[Fast355]

Thanks for the advice :-)
My van seems to run fine around town but point it at a hill or try get it to go up a gentle incline in top gear and feels gutless, people have said to me it would be a cool van to take away and tow a race car behind it but I seriously doubt the vans ability to move anything other than it's self.
At this stage I've fitted a 3" single exhaust system and removed the CAT.
I've contemplated headers but weren't sure what ones were the best as far as fit goes, there seem to be a lot of nice headers avalible for C-K pickup trucks but I don't know if they will fit a G series van.

Doug Thorley made or perhaps still makes headers for the G-van. I have a set of part number 315Ys that were built for the 73-96 G-vans on my 1983. I also had a set of Flowtech 11500 headers meant for a 1973-1987 C1500 truck. They fit well but were cheap, thin, pieces of junk. I much prefer the Tri-Y header design as you get a good gain in midrange grunt and a strong upper rpm charge in the passing gear.

With the 4L60E you won't be towing in OD anyway, you should be towing in 3rd. The van will be much less gutless with the engine turning 2,500-3,000 rpm in direct drive 3rd. That being said depending on the weight you might also want to look at regearing the van. Most of the lighter vans came with 3.42 gears and ~29" tall tire and are only turning 2,000 rpm @ 70 mph in OD. A swap to 4.10s would give you more torque multiplication in all gears, put the engine into its torque curve more quickly, and give you better acceleration. With a ~29" tall tire and 4.10s in OD you would be turning 2,400 rpm @ 70 mph. With a heavy trailer running in 3rd with 4.10s you 2,900 @ 60, 3,100 @ 65 and 3,400 @ 70 and easily pull those hills.

My suggestion on these older TBI engines is learn to tune the EPROM, install headers, exhaust, and change the gear ratio. Once that is done change the valve springs and toss in a small mild single pattern, tighter LSA cam. Something around 206/206 @ .050, .450/.450" lift on a 110* LSA and advanced 4* on a 106 ICL would work well with the right tuning.