Wastegate Dilema!

[3intheBack]

Hi all, i've got a a problem with me booster! I've got an R33 with the RB25DET. I'm half way through my list of mods and have struck a snag. The engine currently has a Garrett T70 turbo, turbo banana's, 4" exhaust, large IC, custom 3' pipework, modified intake plenum, pod, boost controller and a 42mm turbonetics waste gate(WG). Boost is set at a safe 11 psi (because i don't have a computer or injectors yet, i don't want a lean out).

The problem: boost hits at 4000rpm, with Very strong surge of torque, and as the revs climb, torque builds very quickly and stronly. WHEN the WG opens, power seems to stop! lift the right foot, WG closes and power continues. I have come to 2 possiblities:

1: the WG is too big for the set-up at this stage of the build, and is bleeding off to much exhaust gas, or

2: the manifold's waste gate pipe position is in the wrong place, and is causing massive turbulance problems inside the manifold and upseting flow to the turbo.

I got the manifold off ebay, (because i was to lazy to make one)and the WG pipe comes from the bottom of the collector. I was going to change it b4 i used it, but too much vengence from my wife hurried the conversion process!! Needless to say the pipe is still in its original possy.

Has anybody got any other brilliant ideas to the cause of this frustation??

[N I B]

Many of the China manifolds are a total stuff up with number 1 and 6 cylinder running head on to each other and the waste gate also at this meeting point with the 2 runners and the gate only having a 35-40mm exit point to the turbo.

Cylinder 1 and 6 run under 1/2 the temp 2 to 4 run and also stuffing up the AFRs leading to a poor tune and even engine damage and at best great loss of potential power.

Look for the later design that has 6 even pipes entering the base of the Turbo and dual wastegate outlets.

[sky30]

what does your boost read when it happens?

[R31Nismoid]

For your gate (search button)

http://www.skylinesaustralia.com/forums/in...31entry891831

nice and easy. Go from there yourself really.

Have you connected the lines on the gate up correctly and everything (there was a thread on the 2nd page about line connection)

[paulr33]

get a real ecu