Restrictions Effects

[CTX-SLPR]

Howdy,

In a perfect world we would be able to design a perfect plumbing system, but in the reworld we have to make compromises. Since I'm building my own set of headers and the rest of the plumbing for my twins, where do the compromises hurt the worst? Of the 4 fluid paths in and out of the turbo (turbine inlet and outlet, compressor inlet and outlet) can someone please rank ordered where does putting a bend do the most harm and tell me how bad the effects are?

Thanks,

 

[ijames]

Just mumbling out loud here, but I think the lower the pressure/density the more harmful a restriction is. On the compressor side, turbos don't like to suck - look at compressor maps and see how harmful even a small inlet pressure drop is (how much it raises the pressure ratio to achieve the same outlet pressure), while adding a psi or two of restriction on the outlet side isn't so bad. On the exhaust side it works kind of the same way, only backwards - I would worry more about the downpipe than headers and crossover. Also, simple logs seem to work about as well as very nice equal length headers, for manifolds. Anyway, that's the "intuition" I would start with .

 

[Taffy]

Originally posted by ijames
Just mumbling out loud here, but I think the lower the pressure/density the more harmful a restriction is. On the compressor side, turbos don't like to suck - look at compressor maps and see how harmful even a small inlet pressure drop is (how much it raises the pressure ratio to achieve the same outlet pressure), while adding a psi or two of restriction on the outlet side isn't so bad. On the exhaust side it works kind of the same way, only backwards - I would worry more about the downpipe than headers and crossover. Also, simple logs seem to work about as well as very nice equal length headers, for manifolds. Anyway, that's the "intuition" I would start with .

Damn, that was exactly (well close enough anyways) what I was thinking.

There are guys that have gone 11s with the stock headers and downpipes.

I did notice that by changing from the stock IC to a stretch location IC, the tires spun much easier on the low end. This leads me to believe that the outlet of the turbo affects power greatly also.

I would put the inlet to the exhaust side of the turbo at the bottom of the list. Like Carl said, there are a lot of guys going really fast with log style manifolds.

 

[turbo2nr]

You do not want a lot of volume (pipe dia.) of legnth in a turbo header system. You want to retain the heat and velocity of the exaust gas to power the turbo. If gas cools, it shrinks, and velocity will go down. After the turbo, it is a good idea to have a large area to change the spinning, turbulant gasses back into a staight, linear flow, (3" down pipe). Mufflers do not hurt as much you might think. As long as you can hit your target boost level, they really do not restrict much. Very high boost may need less of a restriction in exaust. Temps drop after turbo and down pipe, exaust compresses and cools, so a dual 3" exaust is really an over kill. A sinngle 3" or dual 2 1/2 is fine.
Same for air entering the motor, but in reverse. You really do not need a lot of volume after turbo compressor housing, only takes longer to build boost. Restrictions before the compressor are more important (air filter, pipe dia.) The dia. of pipe can be larger with a larger maf. and a cold air filter placement to get dense, clean air will help. Buy a good book about turbo chargers, I like one from HP books, or a Corky Bell Turbo book.

Scott

 

[bruce]

Originally posted by CTX-SLPR

The Master of V6 header design is Bucci.
Find some of his texts, and fire up the torches.

 

[turbo2nr]

So, does Bucci make buick headers? Never heard of his products. If not, then what good is he?

Scott

 

[turbo2nr]

Well, I will try to find some of his text, to see his theorys of turbo header design.

Scott