Big problem with my power dyno numbers

[camcojb]

Originally Posted by TOM NELSON

340 to the ground is probally about 460 hp.I would check a couple of things one do you have 9 pounds in the manifold at your peak rpm serpentines will slip and if it does the car will feel soft as hell.Two with 9 psi even on a 8.5 to 1 350 with the hot cam you should be making at the very least 580 hp crank and you would definately feel that.I'm not sure if you said your transmission but if it's a auto are you sure it's not sliping,just a thought.Run a compression check on all cylinders see if there within 10 percent of each other and at least 110 pounds cranking.If you have that than i doubt it's in the motor.I've had problems with the procharger units I actually have not used your blower before though but in the past there smaller blowers just did not cut it.I had a 383 with a blower i believe was similar to yours lay down 310 to the ground.We changed pulleys you name it.Not big improvements .Switched to a ysi vortech it picked up 400 hp.and made 710 to the ground and the cam was much smaller than your hot cam.I had good luck with there bigger units like the f2's but even there above 10 psi they really start making heat fast.Ignition Timing can be a huge deal on a 8.5 to 1 motor I've seen 100hp from 25 to 35 degrees the low compression engines like timing at 9 psi and only 6000 rpm But beware carbs timing and boost is a scary deal.If it was mine and i felt good about the tuner i would not shy away from 35degrees total timing at 9si and 6000 rpm this can literally transform the engine.Again beware creap up on it.I would for ****s put some 110 in it and put total at 35 dgrees and see what happens given afr's are in the high 11's low 12's.Hope you fiqure it out

Tom, with his BTM he's only got about 15 degrees of timing at WOT and full boost. I think this is a huge power killer, and gave the dyno guy a couple other things to try. Bottom line, he's got to get more timing in the thing, if that takes water injection or whatever.

Jody

[mazspeed]

Originally Posted by camcojb

Tom, with his BTM he's only got about 15 degrees of timing at WOT and full boost. I think this is a huge power killer, and gave the dyno guy a couple other things to try. Bottom line, he's got to get more timing in the thing, if that takes water injection or whatever.

Jody

Hey Jody, do you think with better cooler airflow, would allow for higher timing settings?

[camcojb]

Originally Posted by mazspeed

Hey Jody, do you think with better cooler airflow, would allow for higher timing settings?

absolutely. Cooler air (through intercooling, water-alcohol injection, and to a degree a cold air intake) will all allow more timing and/or boost.

Jody

[Blown353]

15 degrees is VERY low timing. I would keep bumping it up and keep a close eye on the power numbers and the plugs. I'd be willing to bet it will run best somewhere between 24 and 30 degrees under boost on 91 octane. You're probably leaving 75-100hp on the table running only 15 degrees of timing under boost.

What heatrange plugs are you running? Keep an eye on that too as you bump up the timing. If your heads use 3/4 reach gasketed plugs I'd say you will probably end up with something equivalent to an NGK BKR6ES, that should be about right for that compression and 9 psi of boost. Maybe even one step hotter at 5ES, but start with the colder ones.

With my blowthrough carb setup on 91 octane I was running the distributor locked at 36 degrees, plus another 14 degrees possible with vacuum advance. The BTM box pulled it down to 27 degrees at 15 psi of boost. That's with 15 psi of boost, no intercooler, 9.25:1 compression, and water injection.

Another thing, don't trust the knob on the BTM. Start the engine and run it and use a hand pump with an accurate gauge to apply pressure to the BTM at your maximum boost level, then adjust the knob to your desired timing number while watching the pointer with a timing light. Obviously, do this with your vacuum advance disconnected and at a high enough RPM so the distributor is "all in" if you have the centrifugal advance hooked up. The numbers on the knob aren't really that accurate. In the ballpark, yes, but not exact. I did this on my BTM and made new tick marks on the knob every 0.5 degrees per PSI of *actual* retard as verified by the hand pump and timing light.

[mazspeed]

Originally Posted by camcojb

absolutely. Cooler air (through intercooling, water-alcohol injection, and to a degree a cold air intake) will all allow more timing and/or boost.

Jody

Ok second question, would more airflow allow for more timing even if it's the same temp?

[mazspeed]

Originally Posted by Blown353

15 degrees is VERY low timing. I would keep bumping it up and keep a close eye on the power numbers and the plugs. I'd be willing to bet it will run best somewhere between 24 and 30 degrees under boost on 91 octane. You're probably leaving 75-100hp on the table running only 15 degrees of timing under boost.

What heatrange plugs are you running? Keep an eye on that too as you bump up the timing.

With my blowthrough carb setup on 91 octane I was running the distributor locked at 36 degrees, plus another 14 degrees possible with vacuum advance. The BTM box pulled it down to 27 degrees at 15 psi of boost. That's with 15 psi of boost, no intercooler, 9.25:1 compression, and water injection.

Another thing, don't trust the knob on the BTM. Start the engine and run it and use a hand pump with an accurate gauge to apply pressure to it to the BTM simulate your maximum boost, then adjust the knob to your desired timing number while watching the pointer with a timing light. The numbers on the knob aren't really that accurate. In the ballpark, yes, but not exact.

I agree with the knob, but I do have fast burn heads. Do you think that the fast burn heads require less timing under boost? I heard that they do under N/A.

[Blown353]

Originally Posted by mazspeed

I agree with the knob, but I do have fast burn heads. Do you think that the fast burn heads require less timing under boost? I heard that they do under N/A.

I've never messed with fastburns and boost, but N/A they seem to work well with about 2-4 degrees less timing than a "standard" chamber 23 degree head. I would venture to guess they would also need slightly less timing under boost as well, but probably not 15 degrees low.

However, the only way to tell is to make more passes and keep a close eye on the plugs. Being non-intercooled I'd keep the AFR in the 11.7-11.8:1 range. If the AFR holds steady then add timing and make another pull then check the plugs and look for signs of detonation. If things look good, add more timing and repeat as necessary. Be sure to check ALL the plugs. When I was running my RPM Air-Gap in blowthrough I recall 2 cylinders being leaner than the others so I had to tune for those two cylinders. It was 1 on each bank that was leaner than the rest. I can't remember which unfortunately. That's where the single plane will help.

I'd be real interested to see what your EGT's are with 15 degrees of timing.

[mazspeed]

Took off the filter and gained 37hp. Also it was much cooler today. It was not the filter. Car is going back to Campbell today. I have no idea what to do at this point.

[Blown353]

Originally Posted by mazspeed

Took off the filter and gained 37hp. Also it was much cooler today. It was not the filter. Car is going back to Campbell today. I have no idea what to do at this point.

37hp gain just by removing the air filter is good. Did they also try a pull in the cooler air with the filter on?

I'm still guessing there's another 50+ hp on the table with the timing so low at 15 degrees.

[mazspeed]

Originally Posted by Blown353

37hp gain just by removing the air filter is good. Did they also try a pull in the cooler air with the filter on?

I'm still guessing there's another 50+ hp on the table with the timing so low at 15 degrees.

37hp was because they did it in the morning on a cold run. once everything is heat soaked the power would drop again. There should be 150 left on the table. We should have 500ft pounds at the wheels with this boost and engine configuration.