Brentis

Can someone on this board give me your interpretation of these graphs. One shows the delta of the horspower between a hf cat and a midpipe and the other shows the delta between the torque curves.

I guess what I am interested in is which is faster in a 1/4 mile or track situation, how much, and why. I would suppose gearing would come into play somewhat, but I am not that familiar yet to have a good understanding.

Likewise, I read somewhere that someone had the same 1/4 mile time with a trap speed 1 mph slower with the hf cat. In my world they are effectively the same and the hf cat isn't as loud and will pass inspection.

http://www.efini.net/tqcomparo.htm

http://www.efini.net/hpcomparo.htm

Thanks!

Tom93R1

iTrader: (2)

Those mid-pipe runs look strange, why does he suddenly get a huge surge of power at 6k rpm? Looks like a repeat of the turbo transition. Looking at that graph though, I think a high-flow is definately the way to go unless you really do alot of drag racing. The mid-pipe will win in the 1/4 because you can keep the revs up in its power band the whole time. The high-flow may win on the track where you are verying your engine speed alot more, that would probably be a close call.

KevinK2

insider info:

there is no comparo, Wael had a misfire from transition to 6K with the mid-pipe run.

below transition midpipe run matched the +cat run. above transition the midpipe will kick butt.

ZeroBanger

I posted some dyno graph comparisons with identical boost settings with a highflow cat and then a mid pipe. The difference was 266 rwhp with the HFC and 298 rwhp with the midpipe. After the car was tuned I got 317 from it.

I drove with my HFC for 7 months and enjoyed it, but the mid pipe is more fun to me. I get no boost creep at all. I still spike, but I did with my hfc too.

MP=More Power. hehe.

Brentis

wow 32 horsepower is awesome. One thing that I have been pondering is how important is peak horsepower over mean horspower improvement. (Viper vs. S2000 type analysis) I much rather have 300 hp average over the rpm band rather than 220 hp with a 400hp spike (=equating to an avg. of say 260) wouldn't I?????

ZeroBanger

Look at my power curve before and after my MP (you need to search..oooppps no searchy button). Anyway I like it much better now. I don't notice any difference in low end power, but top end goes nuts. My dyno showed an 80 HP gain from 52 MPH to 60 MPH in 3rd gear. Thats a rush.

racerfoo

what about a mp over gutted cat? big boost in performance?

RX7Elmo

do you mean a gutted stock cat? The stock cat's piping is smaller than a real midpipe. ALso the turbulance from the huge canister (open cat) would cause some drawbacks. I would go with a true midpiipe.

Danny