3.75L Build thread

[Chris@Rvengeperformance]

yeah if my trims were 12.5+ I'd add 10% to the latencies and go from there. It also depends on your mid trim and forgive me if I don't recall what that is. If the low is twice as positive as the mid then add half as much to the latencies and increase the injector scaling the other half since the idle is affected so much by the latencies. etc.

That is the issue with a setup where so much is not stock. Without experimentally derived latencies on a 3/s (the evos MAY be close) you are not sure what is really off.

In the end it doesn't really matter as long as you use some method to get those trims down.

[Chris@Rvengeperformance]

IMHO it is worth it to start with the stock maf and get the injectors scaled in. I understand if that is not feasible though.

[Chris@Rvengeperformance]

if you look here:

Fuel Injector Lag Time

The evo 560 injector scaling is not close to what we and evos use.

[Greg E]

I know. They mark them as 550s and they flow closer to 575-590.

[futurevr4man]

very interesting. i should have time to play with the car tomorrow, and report back.

[CoopKill]

Great build, great info on here!

Cheers Gnat!

[AdamVR4]

im not sure what you are trying to get at? i am going to pressure test through the maf all the way down to the turbo inlets (and cap the inlets). i ALSO want to pressure test to make sure my intake plenum is not leaking and at the same time test the vac lines that are running to it. there are 2 halves to the system. i dont know how much more clearly i can explain that.

Oh, I see where your confusion is coming from... Hope that's not hostility I'm sensing, lol.

And yeah m not gonna dive the car until I pressure test it. I'm not sure how to pressure test my intake plenum half of my blow thru setup, the air will go right out of whatever valve is open. Anyone have an idea on that?

A couple things -

I've never put much thought into the valves because it's never been an issue. It seems that when a 6G72 is turned off, either the intake valves AND/OR the exhaust valves of EVERY cylinder are closed.

Here's an animated V6 because I don't want to think through this.



Seems feasible...


...Pressure testing from the middle of the system just means that after you finish and reassemble, there's a potential pressurized leak point that's gone untested. If it's at all possible (in your case it absolutely IS), remove PRE MAF components on the vacuum side to pressure test........ like your air filters. Cap one intake tube and pressurize through the other.

If your engine is well sealed with loose rings like mine, you'll need to cap the hose coming off the rear valve cover so that you can disconnect the compressed air hose (regulated at 30+ psi) and listen/feel-around/spray-with-soapy-water, in silence, for leaks. Sometimes I wonder if I'm going to find broken ring lands when I take the heads off, haha.

[Chris@Rvengeperformance]

one time when I really wanted to isolate a leak I unhooked the y-pipe from the plenum and put a freezer bag over the throttle body. then I just put the y-pipe on. This eliminates any ring blowby.

I had a pipe off down by the driver side when the sidemounts used to be and the leak was so big it sounded like it was coming from everywhere until I did that to the y-pipe and it helped me pinpoint it.

Picked that up from cbatters.

[AdamVR4]

one time when I really wanted to isolate a leak I unhooked the y-pipe from the plenum and put a freezer bag over the throttle body. then I just put the y-pipe on. This eliminates any ring blowby.

I had a pipe off down by the driver side when the sidemounts used to be and the leak was so big it sounded like it was coming from everywhere until I did that to the y-pipe and it helped me pinpoint it.

Picked that up from cbatters.

Ha, clever. I'll keep that trick in mind when I start cracking FMIC's! Any idea what cbatters is up to these days?

[Chris@Rvengeperformance]

unfortunately I have not seen him post in years. Since his car had somewhere near 200K on it like 5 years ago I'd assume he moved on.

He had a very direct way of posting, but his approach was certainly scientific yet pragmatic. He didn't believe in throwing parts at a problem.