This was an easy pump gas 14psi pull. It made decent numbers but not what we expected. It's an M&A headed motor, not stage II headed. There were timing issues with the Felpro. We need more research in the timing department. We were only able to get 14 degrees of timing as seen with a timing light. It was fluctuating between 9-16 degrees at idle. The question I have is has anyone seen a nearly perfectly flat hp (not torque) curve? This thing was flat from the stall of the convertor to our self imposed 6,700rpm cutoff point. Doesnt seem right to me, maybe timing? Also, the AF was 12.0. Any idea what could cause a flat "curve"?
Dyno'd a stage motor GN. Dyno ?
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I can see a flat torque curve, but flat hp curve? It put ~420hp at 4,300rpm and 428hp at 6,700rpm. Pretty much perfectly flat. There were no spikes or drop offs, just a straight line. Torque peaked at 518lbs at the start, 4,300rpm, and went straight down to next to nothing at 6,700rpm. #s are at the wheels with the convertor unlocked if it makes a difference.
Anyone ever see a flat hp curve?? Were we just expecting too much out of this motor on pump gas, low boost or does the flat line indicate a problem and there's more left in the motor. This is hp, not torque. Torque was on a straight spiral downwards.
Steve Hill
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no expert here but that's not right. The timing is awfully low. I'd want to think about the effect of low timing as referenced to rpm. You really need more timing lead. That's my guess.
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Timing problems
The timing should stay exactly where you have it in the map. To see that it's jumping around all over the place is a problem that will affect your pulls in a major way.
Torque equals HP at 5252rpm...That's where the 2 curves should cross. The HP curve should rise steadily and then peak and roll over. Torque should rise steadily and then lay over some.
I'd look at why the timing is jumping all over first.
What was the fuel pressure doing when this was happening??
What does the data log look like w/ A/f, etc?? Open or closed loop?
The timing should stay exactly where you have it in the map. To see that it's jumping around all over the place is a problem that will affect your pulls in a major way.
Torque equals HP at 5252rpm...That's where the 2 curves should cross. The HP curve should rise steadily and then peak and roll over. Torque should rise steadily and then lay over some.
I'd look at why the timing is jumping all over first.
What was the fuel pressure doing when this was happening??
What does the data log look like w/ A/f, etc?? Open or closed loop?
I guess I should tell the whole story. The car wouldn't idle well. It has way less than 100 miles on the motor. Headers were always glowing. Timing was supposed to be 24 degrees. We took it to the dyno and had the engineer that built the motor meet us there. Timing was 0-3 degrees as seen by a timing light. We got it ~14 degrees messing with the Felpro. The wideband for the dyno was out at the time and we later discovered the wideband for the Felpro wasn't working either. A/F was set to 12.0 while the wideband was working and we were afraid to lean it without seeing the results. Torque took a nosedive from the 4,300rpm starting point to the cutoff. I don't remember what we ended with but it wasn't much.
We've searced for reference angle info but can't find the answer. It's set for 10 degrees. We were told we need a higher number than the maximum advance we plan on running. Maybe it's time to give Jason a call.
We've searced for reference angle info but can't find the answer. It's set for 10 degrees. We were told we need a higher number than the maximum advance we plan on running. Maybe it's time to give Jason a call.
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- May 28, 2001
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timing reference??
Most likely the reason for the red headers is the retarded timing.
The reference for the BUICk is 10*. A check of the actual timing should be made and the 10* reference changed until both the lite and the reference is the same. Could be 7 to 10*. The statement about the reference being higher than the total timing is incorrect. That reference is something used on another setup, not a BUICK v-6. Remember, the DIS ign on a BUICK is a waste fire system. You will have to take this into acct when using a timing lite!!
If you have the WINDOWS version of FAST, go to the "HELP" menu and print it out. It's about 30 pages. It will walk you thru the setup.
The WB should be identified as a lambda sign in the corner of the screen, if the sensor is recognized.
Most likely the reason for the red headers is the retarded timing.
The reference for the BUICk is 10*. A check of the actual timing should be made and the 10* reference changed until both the lite and the reference is the same. Could be 7 to 10*. The statement about the reference being higher than the total timing is incorrect. That reference is something used on another setup, not a BUICK v-6. Remember, the DIS ign on a BUICK is a waste fire system. You will have to take this into acct when using a timing lite!!
If you have the WINDOWS version of FAST, go to the "HELP" menu and print it out. It's about 30 pages. It will walk you thru the setup.
The WB should be identified as a lambda sign in the corner of the screen, if the sensor is recognized.
