You would be pretty close. I am hitting 26psi at 4,000 rpm though.

To be honest, ever since my latest round of mods I have had that odd boost/torque curve. Maybe it's finally now working to my advantage.

Way back when I first got the green with 100 octane:



Funny thing is now I am running more boost on 91 then I did then on 100 oct. Less timing and richer AFR though of course.

 

The most I have personally seen on my own car was 45.7 with spark issues. I was running 32.8psi (WG line pulled) with TurboBlue 116 on that particular run, and saw in the neighborhood of 330. With the way the car was setup recently I was seeing 301-306 running 29-30psi on pump with low timing. I am hoping to see more now overall, though the addition of the MAFT pro is going to alter readings unless I get the VE table something inline with how its set now.

 

Interesting, I saw 300 on one log today when I was adjusting WGDC. 300 load at 27.6psi. 1* ign advance.

 

Isn't all the boost + less timing bad for EGTs? That had always been my concern with dialing in more and more boost.

 

Yes at a point. Unfortunatly I am doing it without my EGT hooked up as I melted a probe last year (2yr old probe) and swapped to an exhaust manifold that isn't tapped for one.

I do need to get it on ASAP.

For me, this is just a study to see how much boost I can get on 91 oct. I don't plan on staying with 27psi. Maybe high 25's on the street. For the circuit, there is no way in hell I would run this tune. The EGT's would be through the roof I could imagine.

 

Yeah this is a drag race or on ramp setup. Road course wouldnt make it I dont think. I took my car to the canyon (okay it was just a deserted road) and ran it WOT for 5 minutes thorugh a 4.11 mile section of pavement that is also a special stage in a clubman rally (deserted, no houses) and by the end I was shooting flame ***** when I'd let off. A sign it was probably a little warm inside there.

 

Bryan (or anyone)

I'm assuming that you did in fact reduce the boost ramp up as compared to a typical MBC setup. And I know you are big on the ECU boost control.

However, my question is, what could the typical EVO owner with an MBC do to accomplish reduced boost ramp up? Would it be possible that a trial and error attempt at finding a proper sized restrictor pill, could reduce initial spiking sufficiently and still allow full boost quickly enough to not negatively effect performance?

 

A pill would probably increase the spike. Something like a secondary inline bleeder might help.

 

OK, you got me. What would a "secondary inline bleeder" look like? I assume you don't mean a fixed bleed port.

It would need to be something that bled initially and stopped bleeding with a slight time delay, correct? Obviously a complicated stepper-motor electro-gizzmo would way over complicate the whole idea.

I'm trying to think of a small mechanically delayed bleed valve of some kind. ???

 

What kinda EGT's would you think is acceptable for say agressive driving and autoX? Maybe the typical 1650f or less?

 

What parameters do you use to combat pulls from high RPMs? I am having a similar issue and I am currently testing with the Boost Error Correction Interval and the Boost Error Correction Tables. Any other variable to play with?

 

Personally, i would try to limit the EGT's to a max of 1600*F for autoX (for such prolonged abuse), some might even suggest less. I only 1/4 mile race with my aggresive tune and I have it dialed in to the point where I don't reach 1650*F until just when I'm crossing the finishline. I have another tune using Tephra's Alt Map switching which can handle long pulls on the highway and such.

 

High timing means more heat in the cylinder and more expanding mixture as the piston is moving upwards.

Less timing means less negative work (pushing the crank backwards) and more heat on the outside of the combustion chamber (and resulting high EGT's). Its important that high EGT's mean cool cylinder temps because the heat is in the exhaust not the combustion chamber.

Turbo cars pull timing with knock for a reason, to focus more energy (and heat) outside the engine to reduce knock and damage. Yes the EGT's go high, but aside from a hot turbine wheel it'll save the motor.

 

Doesn't lower timing put more stress on the exhaust valve though?

 

I don't really think so. Sometimes at most I will have 10-11 degrees at 7000rpm and 30+ psi boost. When it pulls timing I'm down to 4-6 degrees of timing at the same 7000rpm's and I've never hurt a valve or seat, ever. On my DSM I usually pull the cylinder head ever winter just to have a look see at how the parts look and my valves always look fantastic.

The only time I ever hurt a part was when I disabled the knock sensor. I was running 10.5AFR, 5 deg timing at 4000 and 16 degrees at 8000rpm. The car didn't pull a lick of timing and the pistons started melting. So theoretically I was running rich (AKA cool) and high timing (low EGT's). I think I still have pictures if anybody wants a look see.

I also have pictures of a perfectly healthy low timing mid 12 AFR STOCK 160K DSM 4g63.

So IMO detonation hurts parts, always.