3.1's and boost

[boechler14]

im thinkin of over the winter turbo charging my 3.1 and dropping in a 5 speed and i was alittle worried at how the engine would handle the turbo. and if theres anything i should do to the engine to make sure it doesnt blow from the turbo i'm not to sure what kind of turbo i'd be useing so any ideas would be great. the engine has 200,000 km on it but has been running fine and leaks or burns no oil but is it worth it or am i just asking for trouble? thanks

[1990lumina]

Holy shit another Saskatoon member

So anyway, PM TurboSedan....he turboed a 3.1 with over 200,000miles if I recall correctly...

There are other member who can chime in as well, FREE BUMP...

[dbtk2]

The bottom end is strong enough for mild boost levels (like 12psi or less) and the compression is also plenty low enough for boost (8.9:1). The only thing that you'll have to worry about is just setting it all up so it will work properly. For engine management I would recommend a TGP chip and all of its stock management stuff.

Shawn

[TurboSedan]

22pg thread on everything i did with a TON of pics here:

http://www.w-body.com/forum/viewtopi...=22683&start=0

still running great, although i'm still working all the bugs out of it. it was a very low budget project but the results have more than blown me away 8)

[slick]

I've always wondered, didn't they lower the compression on the boosted engines from the NA engines? If so, wouldn't a 3.1 that wasn't boosted originally be a better overall choice (for the fun factor) than an engine with a bit lower compression?

EDIT: This is not taking into account all of the other TGP specific engine parts, just the compression ratio itself. I've always wanted a high compression, rev crazy, boosted car.

[TurboSedan]

the Turbo 3.1 has a compression ratio of 8.8:1, whereas most NA 3.1s have a compression ratio of 8.9:1. not much difference at all of course. the difference in CR is in the heads (and it is noticeable when looking at them side by side). i believe the '89 NA 3.1 used the same heads as TGPs did but i'm not positive about that.

fwiw i did use TGP heads on my engine so i'm at 8.8:1 CR.

[slick]

Wow, I didn't realize the CR was that close between the 2. I've always thought it was a bit more different than that.

[manitcor]

the only think I would say about boosting an older engine is besure to re-do all your gaskets and be sure to compression test each cylinder to make sure you arent getting excessive blowby. Other than that the engine should be good for boost.

[TurboSedan]

i did that and replaced the oil pump and timing chain.

[dbtk2]

Wow, I didn't realize the CR was that close between the 2. I've always thought it was a bit more different than that.

Thats why when I changed my heads to the 3100 heads I wasn't worried about the .1:1 compression increase. There were some members on other forums that didn't think it was a good idea to swap heads due to the compression increase, but its so close that it doesn't matter. I was actually considering running iron head head gaskets to raise it another .4 or so, but that was when I was planning on keeping the T25 and was looking for every advantage I could get.

Shawn

[slick]

I would have used the iron head gaskets. Like you said, any advantage you can get is better than none!