I am a guy with a sick Evo...in some cases there is a difference of 25whp...between a sick and a well Evo....Same dyno...Same tuner...Same day......only 30 mins of time separated the two dyno pulls.......this does not need debating....the problem exists....I only hope Mitsubishi will recall the bad ones to bring them into spec....and not sweep the problem under the rug...it is clear there is more to this that has been posted.....

 

I've forwarded and discussed all of our findings info to Mitsubishi regarding hp inconsistencies between EVOs. On our dyno, which reads ~17% lower than AWD Dynojets that most people are used to seeing, most EVOs have dyno'd around 185 wheel hp. But I've had one dyno at 180, another at 190 and one even at 200whp. All tested in similiar conditions and with identical testing procedure. Yes, this indicates a 10-15% window of variance which is really bit for a stock car. Most WRXs, for example, only vary between 155-163 wheel hp. And the STis we've dyno are all between a repeatable 218 and 220whp.

Just my 2c,
shiv

 

Good point Shiv

What people need to keep remembering is that not only that dynos vary unit to unit, but that dynos do rely on a humn input in trms of weight, etc. It is a pretty longstanding fact that with the roller type dynos (Mustang, Dynojet, etc) you can pretty get whatever HP number you want by manipulating certain values...so the results are really only comparable to the same cars on the same dyno...that is where any inconsistencies would truly reveal themselves. That being said, each car is different, and are very much like fingerprints, so I would say evenna 5% difference in numbers between cars on the same dyno is to be expected. 10% or more, and it does warrant looking into I think, though then again, there may well be a plausible explanation.

Adam

 

mitsubuishi claimed no more or less than 271/273? i guess im lucky then =)

 

[QUOTE]Originally posted by Z1 Performance
Good point Shiv

What people need to keep remembering is that not only that dynos vary unit to unit, but that dynos do rely on a humn input in trms of weight, etc. It is a pretty longstanding fact that with the roller type dynos (Mustang, Dynojet, etc) you can pretty get whatever HP number you want by manipulating certain values...so the results are really only comparable to the same cars on the same dyno...that is where any inconsistencies would truly reveal themselves. That being said, each car is different, and are very much like fingerprints, so I would say evenna 5% difference in numbers between cars on the same dyno is to be expected. 10% or more, and it does warrant looking into I think, though then again, there may well be a plausible explanation.

Adam [/QUOTE)...same dyno, same tuner, same day....Now whats your point?

 

Have there been any more than the few isolated "Stronger running" Evo's turned up? I was lucky, but I also made a connection in my head, my car was one of the cars that got a Quality Control inspection before it was delivered to my dealer.. It had the QC checklist, and had about 50 miles on the car, since I saw the car (And started it) when it came off the truck, the milage wasn't from the dealer. Anyone hear/see anything with regard to some items being re-tuned, or refitted after the cars were shipped over here? There were some rumors about several different fuel maps or ECU versions, no clue if its true since none of the documentation and TSB's indicate any difference.

 

FWIW, there is no need to input vehicle weight to derive horsepower/torque. At least there shouldn't be if the dyno measures wheel output the way it should. That would be like having to input your age on a scale before it gave you your weight. The two are completely independant of each other unless the dyno is also designed to estimate G-forces under acceleration perhaps.

Shiv

 

This may be silly, but is it possible that manufacturing differences in the transmission could be responsible for the observed differences in power we're seeing?

I usually think of the transmission as a system with constant mechanical losses, but could a defective transmission have more loss (in spite of being able to get power to the wheels)?

 

Thats a point .....maybe it is not differences in the motor at all but in the drivelines of different evos? ......Is this possible Shiv?....oh by the way....thanks for my parts they arrived today...cheers

 

Shiv-I believe the observations about the vehicle's weight were in reference to 1/4 mile times (acceleration) where of course it does play a role.

Dan

 

shiv

PS. Dynapacks and Mustang dynos both prompt for vehicle weight in their software. I don't believe they actually use it for hp/torque calculations though...

 

It isn't as important to measure horsepower on a Dyno.. But vehicle weight, where its placed, and how aerodynamic the car are relevent in alot of different types of racing.. but measuring raw or adjusted horsepower/torque on a dyno doesnt really use this information, its only useful information if your trying to do a conversion from trap speed, quarter mile times, or whatnot INTO horsepower/torque calculations, since wheel diameter, final drive gearing, vehical weight all make a difference. Thats why products like the G-Tech pro or the Vericomm performance computer want to know your gear ratio, tire diameter, and weight with driver..

 

Shiv-Sorry, I missed that. I thought you were referring to the post by Tristar about the car's performance. I agree in terms of measuring hp/torque on a dyno weight would have about as much relevance as paint color.

Dan

 

I'm not claiming that it's the cause of the varying HP numbers, but tire inflation does have a sometimes substantial impact on measured dyno performance.

The more flex in the sidewall the more horsepower is "wasted" in continually compressing the sidewall as the tire turns on the rollers. And remember that the car is strapped in place on the rollers, which adds to the effective weight of the car, flexing the sidewall even more. To get the best power numbers, the tire should be inflated to substantially above normal driving levels -- enough to eliminate most of the sidewall bulge, but not so much that the tread cross-section will crown -- perhaps 40psi cold.

This is one contributing reason why your second dyno run may give higher power than the first dyno run, because the tires have a couple of extra PSI of pressure from the heat developed during the first run. Of course there are a bunch of other variables as well, I'm not trying to exaggerate the effect of tire pressure, but it's quite measurable.

 

Actually one of the AWD Dyno's I've seen, actually bolts to the wheel hubs without the wheels... So I can see your point, but there are probably corrections made for that..