Cascade Crew

blue89 · Posted: Fri Sep 14, 2007 12:49 pm Post subject: Turbo questions

I'm thinking of diving into aftermarket domestic turbo.

I see that most people run MAP systems on thier turbo cars. Would it be advisable to run MAF only? Seems like you should be able to run it with the MAF upstream of the turbo and catch everything. I know this system is limited by the amount of air the MAF can effectively measure, but would work without the MAP?

Twilightoptics · Posted: Fri Sep 14, 2007 12:51 pm Post subject:

You go MAF or MAP.

John was talking about this the other day.... why we don't see v6 cars run MAF because they should be under the 255gm/sec threshold of the MAF.

Above that you most definitely need MAP. All forced V8's most likely break that. I know I broke that theshold with a small cammed 355 N/A.

Maf is more forgiving of vacuum issues, while MAP is a little more user friendly to tune.

blue89 · Posted: Fri Sep 14, 2007 1:00 pm Post subject:

I'm thinking of stuffing a T3 on my V6 car. The stock GM maf is good for 300hp, which should be a limit for my block anyway. The only reason why I think it wouldn't work is if the engines efficiency changes at a given boost.

So say 200gm/sec at 0psi MAP uses a INJ PWM of 70% but 200gm/sec at 14psi MAP uses 90%. 200gm/sec should give you a fixed amount of fuel to go with it, right?

And if its the case of the MAF being too small, why can't you increase the size of the MAF housing and adjust for CSA in the maps?

blue89 · Posted: Fri Sep 14, 2007 1:41 pm Post subject:

So the newest idea is to run the MAF downstream of the turbo. That would take into account a change in air density. I would still be hp limited to how much the MAF can read.

rjmcgee · The Hammer Joined: 08 Jan 2004 Posts: 2328

I see melted pieces in your future.

BigDaddyVu · Posted: Sat Sep 15, 2007 9:41 am Post subject:

well you could run the maf sensor before the turbo. not sure how accurate it would be but on the turbo forums i seen both before and after the turbo.

Twilightoptics · Posted: Sat Sep 15, 2007 10:25 am Post subject:

It should be after the turbo I would think.

Also... at 255gm/sec that's the highest voltage the maf indicates. You can't add more fuel above that.

On TPI cars you can adjust the power enrichment to compensate, but you have to be in PE.

blue89 · Posted: Sat Sep 15, 2007 2:03 pm Post subject:

255gm/sec should be plenty to blow into a V6. If a 350 uses the same MAF then I'd be proud if the V6 could flow that much.

BigDaddyVu · Posted: Sun Sep 16, 2007 1:36 am Post subject:

well look at the grand nationals specs. they run on smaller valves. i posted a turbo kit a while back from bbs designs on a turbo charged 2.8 liter v6/. they make good power. just make sure of your 60 degree crankshaft could hold it though.