turbocamaro125

iTrader: (3)

Building a turbo kit for my bmw with 370 swap. Truck manifolds dont fit with the motor back tight to the firewall so I need to make a set of turbo headers but not sure on the size of the primary tubes. I making the crossover 2" to make it spool the fastest and the turbo with probably have a 1.0 F-trim turbine. 1-5/8" or 1-3/4"???? thanks

Sarg

iTrader: (6)

Curious to hear what others say, but on 4 cylinder subaru motors we always used 1 7/8 stepped to 2 inch with a 2.5" collector.

Edit, had the 1 3/4 instead of 1 7/8.

turbocamaro125

iTrader: (3)

I had 1 3/4" on my turbo crx....but it was reved to 9600rpm so idk what size...Im thinking 1 3/4"...

6.0mustang

iTrader: (2)

1 5/8 will keep velocity up and spool faster.

turbocamaro125

iTrader: (3)

true but how much will it hurt top end? Would a 408 or 427 be hurt with 1 5/8 headers?


Phil99vette where are you??? lol

Phil99vette

iTrader: (11)

370", I would do 1 5/8", our 438" ran like a top with 1 3/4".

6.0mustang

iTrader: (2)

I would go with 1 3/4 and at least a 2 1/4 cross over. Make room for bigger motor later

turbocamaro125

iTrader: (3)

it would be nice to see a comparison 1 5/8" with 2" crossover and 1 3/4" with 2 1/4" or 2 1/2" crossover....

mr_biscuitz

iTrader: (22)

So is 1 7/8 way too big for a 408? Engine will be getting bigger sometime soon. Mine now are 1 3/4

Phil99vette

iTrader: (11)

I had 1 3/4" on my 438" and it was a champ, put the 2" headers on and it wasn't the same.

turbocamaro125

iTrader: (3)

Has anyone used a larger primary tube 1 3/4" with a smaller crossover 2"? Or would smaller primary 1 5/8" with 2 1/4" or 2 1/2" crossover be better?

speedracer5532

iTrader: (8)

Might be good to ask this on yb because there are a lot more technical people over there or at least more willing to give advice.

turbocamaro125

iTrader: (3)

got a thread on yb...now too

boostin01

whats yb?

turbocamaro125

iTrader: (3)

Yellowbullet