anyone know of any log manifolds for an sr? i dont care for tubular manifolds aslong as i could have a decent log manifold so i could go bigger boost. aslong as its not too shitty. if im gonna spend close to a grand on a turbo i dont wanna spend the same amount on a manifold. maybe later on in life if i feel the need to go tubular i will but not as of now. thanks for the help ladies and gentlemen. any info would be appreciated.
log manifolds sr?
- Thread starter jdmbrian
- Start date
Spending a grand on a turbo and a bolting it to a log manifold is retarded.
http://www.full-race.com/articles/sr20_turbo_manifold_test_writeup.pdf
If you're gonna do that, why not just stick with a bottom mount turbo like a GT2871r? At the very least you can get an ebay top mount tubular manifold.
If you know somebody that can weld and you're dead set on a log manifold - http://www.forcedfab.com/index.php?cPath=12_162
http://www.full-race.com/articles/sr20_turbo_manifold_test_writeup.pdf
If you're gonna do that, why not just stick with a bottom mount turbo like a GT2871r? At the very least you can get an ebay top mount tubular manifold.
If you know somebody that can weld and you're dead set on a log manifold - http://www.forcedfab.com/index.php?cPath=12_162
z4k said:
extrude hone would be a better process, im pretty sure you wont have access to the entire runner on the cast manifold even with long porting bits.
I can weld cast iron.
But I say get a tubular manifold.
The main reason for doing a log manifold is that you can run an external wastegate. We've been doing externally gated OEM manifolds for some time with awesome results (quicker spool, better heat containment, etc).
There is nothing wrong with tubular manifolds if they're built well. Anything made from schedule 40 will be plenty strong and be able to keep the exhaust in better than some crappy thin stainless piece.
What turbo are you going to be using?
There is nothing wrong with tubular manifolds if they're built well. Anything made from schedule 40 will be plenty strong and be able to keep the exhaust in better than some crappy thin stainless piece.
What turbo are you going to be using?
mranlet said:
I really was not concerned about the weight savings and defiantly was not feeling the additional cost of making a stainless tubular manifold. I opted for 1 3\4 ID schedule 40 steel. Cheaper and stronger. I dont have a full race car to warrant a quality ss manifold. If I were to build another manifold for someone else I would run 1 1\2 dia instead, so the collector would be easier to make into a t3 flange.
i already decided what im doing im getting a manifold from jgs and having my friend finish up the welding on it. im not looking to have the worlds greatest car so tubular isnt in my interest and not in my price range. im only looking for 350hp and getting a t3 t04e 50 trim .48a/r. plenty good for me, and plenty good on a log manifold. calling it a day. later in life if i wanna get something crazy or nicer ill just change the manifold or something but im good for now.
thanks for all the help guys. all comments and advice was great.
thanks for all the help guys. all comments and advice was great.
NAKED MIKE
Spectator
kleen555 said:
I think I will be going this route once my pos ss autochrome finally decides to crack on me. I'm digging the cast for reliability. I am already running the same turbo your getting and all I need is really 300+ whp which should be attainable even using a log style manifold.
why would a tubular mani be better than the one in the link u posted ???? that one clears everything in the engine bay with turbo connected?
kleen555 said:
I think I will be going this route once my pos ss autochrome finally decides to crack on me. I'm digging the cast for reliability. I am already running the same turbo your getting and all I need is really 300+ whp which should be attainable even using a log style manifold.
Shouldn't that manifold be cut between the runners on the flange to help with the expansion differences between the Cast and the Aluminum head?
z4k said:
ehhhhhh, I dont see that being a big problem, why do you ask?
I slot all the manifolds that I build so that each runner has an individual mating surface to the cylinder head. Nothing to do with heat expansion while in use on the car. During the welding process the head flange warps, this is one procedure that I do to prevent exhaust leaks after custom fabrication.
jdmnismo300 said:
Tubular manifolds are much easier to make equal length. Equal length is important for matching exhause pulse phases and ultimately spooling the turbo.
Making casts is terribly expsneive, so ususally tubular manifolds are cheaper than limited production castings. Aside from that, tubular manifolds have a smoother interior finish than cast pieces that haven't undergone some sort of honing, so exhaust flows more freely and helps spool up time.
mranlet said:
::siren:: whoop whoop pull over. The interior of a tubular manifold will be smoother then a rough cast manifold. Along with the longer runners and the equal length portion will allow the engine to flow more air producing more power. Now inferring that having a smoother interior finish will helps spool up time compared to cast manifolds is kinda inaccurate. The exhaust pressure with heat expansion spools the turbo ALOT. And the turbo manifold will see higher air pressures then the intake manifold in boost. A tubular manifold having the longer runners creates a larger volume before the turbine wheel. A larger volume takes more CFM to fill before it has positive pressure. Compared to a short runner cast manifold which is a smaller volume, the smaller volume take less CFM so the turbo makes boost earlier.
