Major loss of HP at dyno
Major loss of HP at dyno Quick Info
I put in a tr224/.561/112lsa CAM, Rev double springs, ti retainers and tr pushrods around last Sept. A week prior FLP LTH, high flow cats, 3" y-pipe connected up to SLP d/d exhaust. I also have ASP Pulleys, ported t/b and the list goes on.
LunaticTA and I got together and bought 2 license of LS1Edit and changed the following.
1. Rev Limiter to 6850
2. COTs disabled
3. MAF table * 115
4. RPM * 115
4. Idle to 850
5. Fans to kick on at lower temps
Now for the question:
Before going to the dyno with stock tuning I was at 368rwhp, 353 rwtq - with the above settings I dropped to 324rwhp 319rwtq. Yes DROPPED ~45rwhp. Even at STOCK an SS will pull better then that with NO CAM or LT Headers.
At the dyno we made some changes which the woman there was very nice and made some recommendations to change the High Octane table to more match hers. This yielded ~20 more RWHP but still more then 20 less then before tuning.
NOW:
I backed out the MAF table to only 105%, RPM stock, High and Low Octane to match the Holden, and made changes from 2400RPM .48 grams over to 8000 down to 1.2 grams to 30 for the HIGH octane table.
Its running to me much better, but any insight to the loss of all the HP that should have put me closer to 390 and not lower, he11 even just increasing the rev limiter should have at least got me 1 rwhp better.
I put in a tr224/.561/112lsa CAM, Rev double springs, ti retainers and tr pushrods around last Sept. A week prior FLP LTH, high flow cats, 3" y-pipe connected up to SLP d/d exhaust. I also have ASP Pulleys, ported t/b and the list goes on.
LunaticTA and I got together and bought 2 license of LS1Edit and changed the following.
1. Rev Limiter to 6850
2. COTs disabled
3. MAF table * 115
4. RPM * 115
4. Idle to 850
5. Fans to kick on at lower temps
Now for the question:
Before going to the dyno with stock tuning I was at 368rwhp, 353 rwtq - with the above settings I dropped to 324rwhp 319rwtq. Yes DROPPED ~45rwhp. Even at STOCK an SS will pull better then that with NO CAM or LT Headers.
At the dyno we made some changes which the woman there was very nice and made some recommendations to change the High Octane table to more match hers. This yielded ~20 more RWHP but still more then 20 less then before tuning.
NOW:
I backed out the MAF table to only 105%, RPM stock, High and Low Octane to match the Holden, and made changes from 2400RPM .48 grams over to 8000 down to 1.2 grams to 30 for the HIGH octane table.
Its running to me much better, but any insight to the loss of all the HP that should have put me closer to 390 and not lower, he11 even just increasing the rev limiter should have at least got me 1 rwhp better.
TECH Resident
Joined: Mar 2003
Posts: 770
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From: Troy Al
Re: Major loss of HP at dyno I agree wholeheartedly, but a few questions.
is the same dyno as before?
did you try going back to base and repulling?
you should have went up a lot more than 1 hp not down, but I am not sure you a comparing apples to apples.
is the same dyno as before?
did you try going back to base and repulling?
you should have went up a lot more than 1 hp not down, but I am not sure you a comparing apples to apples.
Re: Major loss of HP at dyno Do you have a stock maf or ported maf?
I think you should put the Maf table back to stock and adjust the IFR table. We tuned a buddy of mines car before by modifying the maf table and our results were inconsistent and his car felt down on power. Loaded the stock maf table back in adjusted the IFR table to get his ltrms in line and it made a huge difference in the way the car felt.
I would leave the stock maf table alone and do the part throttle tuning via IFR table.
I think you should put the Maf table back to stock and adjust the IFR table. We tuned a buddy of mines car before by modifying the maf table and our results were inconsistent and his car felt down on power. Loaded the stock maf table back in adjusted the IFR table to get his ltrms in line and it made a huge difference in the way the car felt.
I would leave the stock maf table alone and do the part throttle tuning via IFR table.
