so let's say someone is making a manifold for a turbo.

maybe like this one:



since the 2 pipes for the center 2 cylinders are going to be shorter, would it make sense to make those 2 pipes a larger diameter than the longer ones to try to compensate for the difference in length?

t25 a good size for an a15?

A mate and i have just finished just finished doing something similar to an a14... the length of the runners on the exhaust manifold will be fine .if they were equal it would be better but i think the difference would be tiny.. a t25 is perfect , we had a t3 something on the a14 worked well after 4000rpm bit laggy before though..

well then. I'm going to start collecting the raw materials. I've found all the stuff except the manifold flange for the engine side.

So equal length would be ideal, but it's not the end of the world.

I'd like a turbo that takes advantage of the lowend torque and lower redline of the A15 so if the turbo peaked at 7000 rpm that's fine i shift at 6250

what specs should i be looking for in a turbo? we know t25 flange, what else? I know i want oil and watercooled bearings.

I'm probably going to make it blowthrough at first for my fuel system either way is easy. No carbs to box :)

I guess I'll use my wanky BOV that's left over from my failed e15et project, suppose that means i have an intercooler already too :)

I'm kind of excited, it really seems do-able. I know it is. Plenty of A series turbos out there.

blowthrough dosent that mean you will have to box the carbie? or do you mean suck through if so you wont be able to use your intercooler

I have a totally different sort of carb. I can blow through it doesn't need boxing, and can be intercooled, the suck through would not be intercooled.

i'm very well aware of why not to intercool a suckthrough.

my mates a14 had a downdraught webber of a ford cortina or similar..worked well..

turbo spec's not certain on , try and get one from a nissan ca18det motor that was in the 180sx..

the watercooled ones are a pain in the arse.the kunt was always running hotter..

why are watercooled ones bad? I thought the oil and watercooled ones were best for the life of the bearings.


ca18det sized turbo is going to spool up slow seems like I want something like what an e15et had.

not bad just ran hotter than normal..
an they are a pain in the arse cause of more pipework.

as for turbo size i guess the smaller the better .. to an extent

what ran hotter? the coolant temp?
You probably needed a bigger radiator to deal with the increased power anyways.

Your water temp will run hotter unless like you said have a massive radiator but IMO just the oil cooled turbos are better because there is more room for oil and the oil cools and lubes your bearings the water only goes around the outside and there is less piping like DAT12S said.

I believe a T25 would be the smalest you could go without restricting top end performance just depends howmuch boost you run i supose