I have a lt1 with hoged out trick flow heads 30lb/hr holley injectors lt1 stock intake granetelli maf 383 rotating assy edlebrock headers full msd ignition high flow cat
I put it on the dyno and it only got 285 hp at the flywheel am i wrong or shouldnt i be over 400 with this engine?? what could be the problem?

 

Did you tune the PCM after all those mods?

 

I took it to get the pcm tune done and they said they did some of the tuning and they only did one run and told me that it was putting out the 285 at the flywheel. I checked all the wires to make sure they were run properly. They are going to do another base line run this afternoon and let me know if reseating the plug wires did anything, im sure it wont. Is there something specific in the pcm tune that has to be done first? Its a 96 z28 and i know there were alot of things done differently for the 96 and 97 pcm's

 

i noticed that the numbers he gave me 285 hp and 325 tq were exact to what the factory advertised for stock

 

ok the pcm tune put me at 285 on the ground. It is showing an intermitant miss on cylinders 1 2 and 3, i think that i missing about 80 hp, could i be loising it there? Also was doing the test where you shut down injectors one at a time to see the effect on the engine and the no 7 had almost no effect but i know its firing should i do a compression check there?

Wes

 

Misfires will kill a lot of HP. Apparently #7 cylinder is just going for the ride. Make sure that all the injectors are being fired, hook up some NOID lites. Also fix the intermittent misfires, plugs may be fouling or the wires going bad. A compression test won't hurt but won't help if comes out OK. Also didi they give an A/F ratio chart, is the mixture rich or lean?

285 at the wheels is worth about 350 at the flywhhel, which considering your mods should be around 400. You could make good use of a bigger cam considering the better heads and larger displacement.

 

i changed the plugs on the 1 3 5 7 b/c thats where i had the most problems and the plugs were a little black from running rich but not built up bad. I didnt change the plugs on the other side yet b/c I have to pull the headers to do that and not really looking forward to doing that. I do have a cam upgrade its not huge b/c I didnt want to wreck havok on the vacum but it is a larger cam. Its was running extremely rich b/c the tuning hadnt been done untill i reached the 500 mile mark and that was why i was afraid the plugs may have fouled. The #7 cylinder may have been an issue with the tuning not being completed yet. Im taking it back to the dyno in the morning with the new plugs on the odd side to see if that cleared up the intermitint missfires on the 1 and 3 also to get the tuning fully done and see if that # 7 comes back online. He said it made a difference when he shut it off it was just very small. all the plugs and wires were changed out at the rebuild along with a new opti. Ive heard that some ppl have had problems with the msd wires coming bad brand new so tonight i will do the dark check to see if i can see any arcing. Thank you for any advice and i will get some noid lites. I will let you know how the dyno goes tomorrow