3900 Manifolds

[Blackrider]

Hey guys I need a few opinions here. Since we're having a hard time getting headers made for the G6, I'm open to anything. Here is a stock LZ9 manifold off the G6, the inlets of the manifold a fine they are large "D" styles measuring 1 6/8th wide, however the outlet into the cat is only 1 7/8th. Looking at the flange on the cats, they're well over 2 inches. I'm going to go pick up some gaskets to get the exact measurement today, I want to gasket match the manifold to the CAT.

Thoughts?

[IsaacHayes]

So all there is to grind is the flange it looks like? It doesn't taper down in the collector, just the flange opening is small? Looks like an easy mod.

I say that would free up some power. Both with extra flow and reducing turbulence (if it doesn't taper and just hits that flange).

[Blackrider]

So all there is to grind is the flange it looks like? It doesn't taper down in the collector, just the flange opening is small? Looks like an easy mod.

I say that would free up some power. Both with extra flow and reducing turbulence (if it doesn't taper and just hits that flange).

Yeah basically, I took it in to the Machine shop and the guy said he can open is up quite a bit, he's also going to clean up the casting a bit, he's going to charge me an hours labor which is about 65 dollars. The damn gaskets where more expensive!

[IsaacHayes]

$65 for a porting job is pretty cheap and saves you a lot of time of using a die grinder hhaha!! Is that for both manifolds?

Do post any gains you feel!

[Blackrider]

$65 for a porting job is pretty cheap and saves you a lot of time of using a die grinder hhaha!! Is that for both manifolds?

Do post any gains you feel!

Yeup for both.

[SSsuperstar]

hey Blackrider. How well does the Performance ECM/TCM Tune for your 3900 work? Do you think it would work for my car as well, seeing as how I have the same motor in my Malibu SS. would the fact that I have a 4 speed automatic transmission make a huge difference? I'll also have to look into making this mod for my car as well.

[Blackrider]

hey Blackrider. How well does the Performance ECM/TCM Tune for your 3900 work? Do you think it would work for my car as well, seeing as how I have the same motor in my Malibu SS. would the fact that I have a 4 speed automatic transmission make a huge difference? I'll also have to look into making this mod for my car as well.

It should work in your car, visit www.vectormotorsports.com and send them off a quick e-mail.

Its really worth it, it made a pretty big difference.

[El_Diablo]

so did you ever do this? what were the results?

[Blackrider]

so did you ever do this? what were the results?

I have the manifolds however I've been to busy to put them on, maybe this weekend.

[SSsuperstar]

What sort of horsepower gains did you achieve with the ECM/TCM tuning? 10-20 hp? Maybe more. I'm gonna be ordering this component soon..maybe sometime in November. What is your rev limiter set to? I know stock i can't rev more than 4000rpm in park and neutral. Have you Dyno tested your car and see how much horsepower your putting out? Let me know anything that you know.

[El_Diablo]

the 4k rpm park/neutral limiter should never be changed IMO, its not good for the engine to spin that fast without a load

shit points, if anything like tuners have been doing for the previous generations should be moved to around 6.5k rpm, its just a tune, most improvement comes with the trans, dont expect any huge numbers, you dont drive a vette

taking into account your stock i could possibly see you gaining between 3 and 15hp depending on what they've done to detune your engine, but really im guessing its not much... that trans portion of the tune is what you'll really feel though

[Blackrider]

The Tune netted 10WHP, I put down just about 200. The Dyno guys told me that they're dyno had been putting out lower number the past few days. (How they know this I have no idea) Also I was losing 2 degrees of timing due to IAT.

[SSsuperstar]

So your 3.9 puts out 200 wheel horsepower after using this tune? so the 240 bhp gives you around 190 whp? okay....so i should expect similar results as well?

[Blackrider]

So your 3.9 puts out 200 wheel horsepower after using this tune? so the 240 bhp gives you around 190 whp? okay....so i should expect similar results as well?

Depends on the dyno, if I used a dyno jet it would have probably been 225WHP. They're more a tool for tuning.

[SSsuperstar]

what is the down pipe used for? Also which is better? using the TCM/ECM Tune from Vector? or ordering the HP Tune? Or can both be used together? Does the Vector unit come pretuned? or can it be adjusted after installing it?