Thread: New setup and build....Updated 5/25/12...723whp!!!!!!

ill have the mad scientist chime in

I havn't ran 20V cams on my BB yet but, the N1's feel great and it pulls to 9200rpm(limiter) without feeling like power falls off.

What crank damper are you planning to run? I would get a 7" damper if your planning on revving to 9.5-10K.

Backpressure should be non exsistant with a tubular manifold, 82mm turbine wheel and an open exhaust right out the hood.

Where can i get those 'bungs' that you welded in for the injectors?

We all know the SR16 non n1 cams work great with big turbos and turbine housings, tubular manifolds, and open downpipes. The n1's in all reality, have slightly more lift, slightly more duration, and slightly more overlap compared to the non n1 cams. This should all work to my advantage on my setup. As long as you can keep backpressure down below 1:1 ratio the bigger the cam the better and the overlap will actually be benificial instead of a negative thing compared to a more restrictive setup.



I plan to use the stock VE crank pulley, I ditched the aluminum non dampened pulley. Ive used the Gspec pulley on several VE motors reving to 9000-9500 and so far no sign of bearing damage at all. I think the VE pulley will do just fine. I was debating on getting the ATI Damper but again not trying to throw money out on stuff that isnt needed and IMO its not needed. I definitely wouldnt recommend anyone use an undampened pulley reving past 9500 though.



Exactly, the setup should flow like no other and it will put the powerband where I want it and still should keep backpressure under or at the 1:1 ratio at all times.

Hey ashton, how do you calculate the back pressure to XXX ratio?

and what is XXX...

Have seen n1's make a gain over 16ve's on a big turbo build

The ratio is backpressure to boost, in a perfect world you want the backpressure as close to 1:1 as possible or under. Never over. The more over you go the more likely you are to have problems with reversion with large cams with a lot of overlap. This can cause heat problems on the pistons which will lead to detonation.

Higher backpressures will help with spool, so thats why depending on setup flow will determine what cams you should be running to be most efficient. If you want a great spool time, use a small housing, large lift, little to no overlap cam set and you will be fine with the higher backpressures.

thanks man, so youre saying if your using 20psi u want to keep backpressure also at 20psi... how do you calculate back pressure?

You have to measure backpressure and compare it to your boost level. You tap a steel line into the collector and run about a 3 ft line or longer to a buffer which is basicly a just a small canister to help equalize pressure and get rid of pulses in the system to get a nice smooth signal. Attach either map or boost sensor to the other end of the canister and monitor or log pressure.

Again it all depends on setup. With a cam set with fairly little overlap you can get away with above 1:1 ratios without problems but with larger overlap cams it will only cause issues. There are many things that affect backpressure. Backpressure is a direct relationship to the efficiency of the engine and turbo system.

Cams, fuel type, turbo manifold, turbine housing size, exhaust system flow, a/f ratio's, timing and egt's all things that can affect backpressure.