[johnta1]

Thoughts?

I would go methanol!

No getting hot, or too much CR. More power.

[RAIV-Z]

Originally Posted by charlie66

When you say AFR was lean , what was it? Whats your timing at 30 psi?

Let me clarify the lean comment. It was lean at idle after starting it up after sitting for about a week.


AFR during a run was 11.9 to 12.2
Timing at 30lb was peak 27 degrees

[RAIV-Z]

Originally Posted by johnta1

I would go methanol!

No getting hot, or too much CR. More power.

Methanol, sometime in the future when we decide to drop weight. I'd like to figure this out before switching fuel.


CR is 10:1.


Another theory, valves hanging open/not sealed? We were having issues with lash going away.

[charlie66]

27* is a lot of timing for 30psi . Didnt they move the plug over to in front of the exhaust valve an give this head a heart shaped chamber? Thats a real efficient chamber . I have the new Edelbrock head with all that done to it and @30psi it only wants 18*. Something to try would be taking some timing out and richening it up a bit more . What are the egt's at 30 psi with 27*?

Originally Posted by RAIV-Z

Let me clarify the lean comment. It was lean at idle after starting it up after sitting for about a week.


AFR during a run was 11.9 to 12.2
Timing at 30lb was peak 27 degrees

[cgeise]

the time it build boost at launch seems way to long -- how much timing are you pulling at that point????

[RAIV-Z]

Originally Posted by charlie66

27* is a lot of timing for 30psi . Didnt they move the plug over to in front of the exhaust valve an give this head a heart shaped chamber? Thats a real efficient chamber . I have the new Edelbrock head with all that done to it and @30psi it only wants 18*. Something to try would be taking some timing out and richening it up a bit more . What are the egt's at 30 psi with 27*?

The chambers are heart shaped. No EGTs yet. When we get it back together, we'll pull a bunch of timing out and then ramp in back in slowly again.

[RAIV-Z]

Originally Posted by cgeise

the time it build boost at launch seems way to long -- how much timing are you pulling at that point????

On most of the passes we weren't pulling timing on the brake, it was at 32. When we did try pulling timing on the last run when it stalled on the line, it was at 30, which was not expected as the timing offset was set to pull 12 degrees.

[cgeise]

seems like something is wrong -- we were pulling 8 or so on the brake over 5000 or so rpm and the boost was in 1.2 seconds. we set the programable waist gates to ramp up from a low setting to max setting in steps over about a second or second and a half, maybe 4 or 5 steps.

[cgeise]

Do you have EGT's???? we ran the car rich -- 11.5 or so and had egt's in the mid 1600 range after we changed to a better exh. housing we were pushing 1800 with the more restrictive one.

[RAIV-Z]

Originally Posted by cgeise

seems like something is wrong -- we were pulling 8 or so on the brake over 5000 or so rpm and the boost was in 1.2 seconds. we set the programable waist gates to ramp up from a low setting to max setting in steps over about a second or second and a half, maybe 4 or 5 steps.

Yeah, we need some tuning work here.

[RAIV-Z]

Originally Posted by cgeise

Do you have EGT's???? we ran the car rich -- 11.5 or so and had egt's in the mid 1600 range after we changed to a better exh. housing we were pushing 1800 with the more restrictive one.

No EGT's, Average back pressure ratio over a run is ~1.5:1.

[RAIV-Z]

A few before/after pics of the chambers.

[charlie66]

That 4th picture is really showing that its getting way to hot. Its melting the aluminum . That looks just like my E-head chamber with the spark plug moved real close to the exhaust valve and a heart shaped chamber.

I had to reduce all my timing when i changed over to the new style head . Just to give you an idea , I ran 24 degrees at 30psi with the old head design. Now its 17 degrees @ 30psi with new head. 40Psi was at 18* now its at 12* .

Do you have Inconel exhaust valves installed in your heads?

[charlie66]

I forgot to say, You did a really nice repair job on your chambers! Looks excellent..

Good luck ...

[mgarblik]

We had Edelbrock and Tiger heads that looked allot like your before pictures when we were running the Grocery Getter. Just not allot of real estate between those seats. The copper beryllium seats hold position long after the aluminum is softened and blown out. The fix for us was to completely ignore the "experts" who were guiding our tune-up based on Chevy combinations. After melting 40 pistons in one year, we began taking out large amounts of timing and the problems went away. Every time we took out timing, the car went faster and lived longer. We kept taking it out a couple degrees at a time until the car finally slowed down. That ended up being total timing of 6 degrees BTDC, spraying 600 HP of nitrous in Tiger heads. The digital MSD box allowed 25 degrees of retard and we used 24 of it. Base 30 degrees, 6 degrees down track.

I fully realize, you are twin turbo and there is no direct correlation between our nitrous tune-up and your ultra sophisticated turbo set-up. But just like our engine, your's is telling you something. It doesn't like that much timing and it is melting the aluminum. We were just amazed each time we reduced the timing, the car just loved it. Best of luck with the tuning process.

[RAIV-Z]

Originally Posted by charlie66

That 4th picture is really showing that its getting way to hot. Its melting the aluminum . That looks just like my E-head chamber with the spark plug moved real close to the exhaust valve and a heart shaped chamber.

I had to reduce all my timing when i changed over to the new style head . Just to give you an idea , I ran 24 degrees at 30psi with the old head design. Now its 17 degrees @ 30psi with new head. 40Psi was at 18* now its at 12* .

Do you have Inconel exhaust valves installed in your heads?

Yes, Ti Intake and Inconel Exhaust. When we get it back together well pull the timing way back to start with again.

[RAIV-Z]

Originally Posted by mgarblik

We had Edelbrock and Tiger heads that looked allot like your before pictures when we were running the Grocery Getter. Just not allot of real estate between those seats. The copper beryllium seats hold position long after the aluminum is softened and blown out. The fix for us was to completely ignore the "experts" who were guiding our tune-up based on Chevy combinations. After melting 40 pistons in one year, we began taking out large amounts of timing and the problems went away. Every time we took out timing, the car went faster and lived longer. We kept taking it out a couple degrees at a time until the car finally slowed down. That ended up being total timing of 6 degrees BTDC, spraying 600 HP of nitrous in Tiger heads. The digital MSD box allowed 25 degrees of retard and we used 24 of it. Base 30 degrees, 6 degrees down track.

I fully realize, you are twin turbo and there is no direct correlation between our nitrous tune-up and your ultra sophisticated turbo set-up. But just like our engine, your's is telling you something. It doesn't like that much timing and it is melting the aluminum. We were just amazed each time we reduced the timing, the car just loved it. Best of luck with the tuning process.

Thanks for the feedback. We're also going to soften up the chamber a bit on this go around.

[RAIV-Z]

Hub Dyno Session last December, EGT's looking a bit on the hot side.

[Stan Weiss]

Very nice numbers. How much boost is this at?

Stan

[RAIV-Z]

Hi Stan,

That was at 28.1lb peak boost.