Hi all,

 

SO as the title says, turbo manifolds!

 

I have a 4agze big port from an ae92 levin and at the moment have a sc14 for the upgrade and was going to run a rdw manifold for my ae71 with bov style, BUT I am now considering turbo (probably easier) and was wondering what the best manifolds are to buy?

 

Is there a big difference in cast iron, stainless steel, steam pipe etc for longevity and quality?

 

I know kelway is good and local to S.A!

steam pipe for longevity. Longterm the stainless doesnt handle the constant temp change.

Any particular style that would best suit fast spooling? I would guess the shorter the runners/primary the better, right?

keeping the runner diameter as small as possible(within reason) for more velocity works wonders for drivability and spool.

 

changing from 32nb sch 40 (35mm ID )to 25nb sch10 (28mm ID )steam pipe runners i gained roughly 20hp throughout the whole rev range

even top end on a vvti 1jz with a gtx3076 and was so much better to drive.

 

 

i'm currently making a sr20 manifold for myself from 32nb sch40 but may make anther later out of smaller ID and see if spool can come on sooner without choking it up top as the sr20 exhaust ports are much bigger then the vvti 1jz + with 499cc per cyl for sr compared to the 415cc per cyl for the 1j

 

havent found anyone who has tried 25nb on a sr20 yet so may be a first

so would you keep the runners the exact same ID as the exhaust port on the head, all the way to the collector/turbo flange?

Makes sense to me what your saying, I know exactly what your on about with the velocity. It's the same with an N/A exhaust system, can't have it too big or you loose power, or in this case response/drive-ability.

 

any more info will be great!

i'm not sure on the size of the exhaust ports on a 4ag but doubt it would flow too much for a 25nb sized steam pipe manifold

with only 396.75 cc per cyl , when a 1jz is 415cc and it was perfect size

 

but i'm no expert

 

you just need to do research and find out what most 4ag manifolds are pipe diameter wise , and hope some one has tried the small runner i have suggested with good results