I just got home from the Dyno a little while ago (dynojet). The mods are below. Because of my gears, the tuner only did a second gear pull. He said that in third with those gears he'd be spinning the dyno around 160mph and he didnt want to do that. The next step for me is to get 4.10s because I really think that will help, and will also give me a more accurate reading. I was a little let down with the numbers, but in a second gear pull I got 290 hp at 6100 rpm. The guys there said that a third gear pull would add about twenty-thirty hp. So I'm guessing that I laid somewhere between 310-320 rwhp with this setup. What's everyone else think? Does that seem accurate?

4.8 liter with 212/218 predator cam
Pacesetter LTs w/ ORY
Ported & Polished heads, 241 castings
Eaton Posi w/ 3.42
Dyno Tune

 

The gear you dyno in has no effect on HP/TQ numbers so long as the dyno gets enough samplings to be accurate. The dyno knows RPM and can caculate gear ratio from the known MPH of the rollers.

Most dynos run in 3rd gear simply because it takes longer to run up to redline and they can get a more accurate reading because 2nd usually goes by to quick. Case in point, I dynoed my '70 vette in 3rd and 4th gear (I had 4.10's and a close ratio 4 speed, so both went by rather quickly. 3rd was 510 HP and 500 tq, 4th gear was 508 HP and 501 TQ, both well within error limits from run to run, same gear or not.

Did you get an A/F readout? That's about the only way you would know if there's more left in your combination. Post the sheet if you have it too.

 

I totally forgot to ask him for it, I meant to. The A/F was about 12.5 or about that. I know it was below 13 and above 12. I should have gone with a little bigger cam, but its my dd so I guess its not all bad. It's got good mid range. A guy i know has a 5.3 with a 228/231, its a dyno queen (363 hp) but it doesnt pull til like 5800. He only got me by about 3 cars. So im thinking with 4.10s, a shift kit and stall, and a 50 shot I should be alright.

 

4.10's, a stall, and some juice, you will kill that dyno queen. you would be so far ahead by the time his starts pulling that he would probably quit.

 

not bad for hp numbers, i took my truck over to have it tuned on the dyno, total waste of money, he did nothing really but took my money. anyhow i pulled 268hp and 390tq, this in a 5.3l LT's with 3" custom pipes,CAI, 259 comp cam, i was hopeing to see a few more hp's and he said he could tune for more but didnt so i was a little pissed.

Tim