[bryansMtngto]

ok started toying with my 77 T/A tiwn turbo project while i was cleaning garage over last few days. Thinking about making 3 in logs that reduce to 2 1/4 at the turbo flanges. Is there any pros or cons about doing a log style compared to a tubular set up? just figured I could really keep it clean and i got the mats lying around. What ya think?
got both a 400 and a 455 D headed engines not sure which i'll use for a finish yet was mocking up on the 455.

[Tom Vaught]

JMO, Gale Banks has made over 1000 hp with a small block chevy engine USING LOG MANIFOLDS.

http://bankspower.com/twin-turbo-products.cfm

This Ford GT has made over 1000 hp with a 331 cid engine.

http://video.google.com/videoplay?do...38952289885249

A guy who used to post on here: 455Turbo made over 1000 hp with with a Pontiac engine and fabricated log manifolds.

Biggest deal with log manifolds is making the volume large enough that there will be minimal exhaust port flow interference on cylinders farther away from the turbo inlet flange.

Go for it.

Tom Vaught

[Craig Hendrickson]

+1

H-O TurboForce used log manifolds and IMO that was not the restriction in the system.

[bryansMtngto]

Tom for one the Ford GT is a Dream car of mine Just awsome vid. ok I also have some 4 1/2 in Pipe from a diesel build i did while back Im not after huge hp this will be a daily driver figureing 700-800 using a pair of small turbos off a Mits. eclipse. But was thinking the 3 in should be large enough for my goal. Or do you think the 4 1/2 would be better for the main log??

[R 70 Judge]

Originally Posted by bryansMtngto

ok started toying with my 77 T/A tiwn turbo project while i was cleaning garage over last few days. Thinking about making 3 in logs that reduce to 2 1/4 at the turbo flanges. Is there any pros or cons about doing a log style compared to a tubular set up? just figured I could really keep it clean and i got the mats lying around. What ya think?
got both a 400 and a 455 D headed engines not sure which i'll use for a finish yet was mocking up on the 455.

I basically have what you are describing in 304 stainless including custom 3/8" stainless flanges. 2 1/4" primary into a 3" log. Probably need to buy a couple more elbows to have enough to finish them off.

I was going to use them for a future turbo project, but I may part with all of it.

Trying to locate old pics.

304/304L stainless in Schedule 10 (.109" wall thickness)
Six 45* 2" elbows (butt weld x butt weld)
*** 90* 2" elbows (butt weld x butt weld)
*** 3" to 2" reducing couplings (butt weld x butt weld)
*** 3" Unthreaded pipes

The 2" pipes actually have an internal diameter of 2.157"
The 3" pipes actually have a internal diameter of 3.26"

[opnwide]

I think those 3" pipes will work fine, and those little turbos will make great boost down low. You'll love the throttle response!

[bryansMtngto]

kool thats what i was hoping to hear. And thought from following some other builds. Just trying to use up a bunch of parts and raw mats that i have lying around. and Work on my fab skills have gotten a bit rusty. planning on a fun winter out in the garage between the 3 cars.

[BruceWilkie]

Here you go....

I just cleaned my shop and re-organized everything. Found this article and left it out of the box. HotRod May 1981 Pressure Perfect. Gale Banks twin turbo kit using fabbed logs.

I've scanned the page that shows them.

Dont go too large on the piping to the turbine... just step log ID up at each point the primaries merge. Primaries in the 1.75" range should work well and 2.5" at the turbine entrance should be fine.

On the turbine outlet side.... large as possible from all I've read/seen. Someone on YB's turbo forum recently disconnected an already large downpipe(larger than turbine outlet) and dyno'd open off the turbo and picked up more power. I believe the topic was expansion chamber.



(I have a pair of the turbos pictured but probably only good for @8-900 hp maxed out. Probably going with a pair of S472's)

[lemans411]

i went 9.46 @ 143 in my 4100 lb car with log manifolds. just saying