Mishri and I took our cars to the dyno and did a couple pulls each. His results were pretty good and mine left me wondering why my car seems so weak. Here are the critical differences between the two cars, and I will post the charts at the end.

Mishri - 4.10 FRPP, Steeda CMDP/UDP/CAI, Brenspeed 93 Tune, Auto Tranny
Riptide - 4.10 FRPP, JLT Intake, Brenspeed 93 Tune, Manual Tranny

Mishri runs 17x8 stock bullits with the pirelli 235/55/R17.
Riptide runs 18x10 DD bullits with Nitto NT05 295/45/R18.

Mishri's results: 285.7 whp, 304.4 wtq
Riptide's results: 265.8 whp, 275.0 wtq

Yeah Mishri has some power mods but I have a manual transmission which should mean less drivetrain loss. The pulleys and plates aren't known for huge gains.

Are my larger rims and tires really going to make THAT huge of a difference here? What gives?

SAE corrected results/charts. 4th gear pulls to 6500rpm.

Mishri:


Riptide:

*Apologies for the colors. I didn't have a red pen handy. Blue is hp, black is tq.

If you're having trouble reading them, here is a link to the (huge) unedited images.
Riptide: http://tinypic.com/r/15qx83b/3
Mishri: http://tinypic.com/r/10zq0qg/3

 

Many things may be at play here: Initial stock HP, condition of the engines (mainly plugs), fuel... Although 20 RWHP DOES seem a bit excessive. I could see about 10 RWHP difference based on stock differences and maybe 5-8 RWHP for the delete plates and pulleys so we conceivably COULD be looking at 15 RWHP or so. I doubt the minor difference in tire size would be a factor but I haven't had a lot of dyno experience in years.

 

Both cars were datalogged last week and neither is having any problems with detonation. Both are using the same tune (brenspeed) though the trannys are different. My car has 14K miles and his has 7K. Same stock motorcraft plugs. I have pulled mine out and done the TSB. He hasn't yet.

Here's mine on the dyno.
http://tinypic.com/r/2qdo220/3

265whp is pretty disappointing for a car that has an intake/tune installed. I was pissed about this when I saw the results. Not sure what I can do about it and my main concern is that I was "blessed" with a factory turd.

 

10hp easy with pullies and CMDPs...maybe 15. Also what where the stock runs?

 

Neither one of us ever did a run with the cars completely stock.

However, both our runs on this dyno were within 1/2 hour of each other if it matters or not.

 

I feel you man. Take a look at my mods, then my dyno results....I was running 20's on the dyno so who knows if the tire size matters.

 

Your wheel and tire combo is significantly heavier, but it should only account for a few HP difference. It seems his mods, or maybe his CAI tune combo, are outpacing you a bit.

 

I figured my transmission should easily make up for most of what his pulleys and plates are getting him. I expected our numbers to be much closer than this. From what I've read around here my car should be getting more like 275-285whp with the intake/tune alone. 265 would be more typical of a stock GT.

Stuff like this makes me want to push the car off a cliff and start over. Obviously that's an overreaction at this point.

But I have to wonder. If the car is one of the weak ones from the factory is this worth going further with mods or should I ditch it now and get something else. Sure it's only 15-20whp or so off but why try and mod something that's a snail out of the gate? I'll always come up short.

**** me and my terrible *** luck.

 

If you have money and time to waste, put the stock wheels on your car (or swap with Mishri) and go back to the dyno and see what your results are.

 

Did you drive the car for the dyno run? I've had a 13 rwhp difference between runs just from me not punching it correctly. This was while I was NA with similar mods to yours. With a Brenspeed 92 tune, 4.10 gears, udps, and Bullitt intake I made 285 rwhp.

For all you know you could of had bad gas and your car was pulling timing. Did you get the whole datalog to compare to the other car?