Noticeable horsepower difference in two stock r53's
 

Hello all,

I want to start off by saying that I am relatively new to minis and recently switched from my subaru impreza wrx to an r53. My wife and I collectively own two r53 mini cooper s models. Mine is a 2002 with 73k miles on it and hers is a 2003 with 53k miles. Keep in mind both of these minis are virtually stock for the exception that mine the 2002 has a k&n intake system on it. We both bought them from seperate dealers within the past 5k miles on them and both were said to be tuned up. Both are run on 93 octane every fill up. Both of us are very conservative drivers and do not abuse the cars. The other day I finally drove hers to see how it would drive compared to mine. Upon doing so, I noticed quite a big difference in throttle response from her car to mine. Her 2003 was quite a bit more responsive on the throttle in each gear compared to mine. With hers you only have to push the throttle lightly to accelerate and get into the powerband, whereas mine you have to push the gas pedal down quite a bit more to get it to go. Along with this, it seems to take a lot less pedal to get in the supercharger compared to mine. Once, they both get into the supercharger they pull nearly equal but mine just takes a considerable amount more on the throttle to get going. All in all, her throttle response time is a whole heck of a lot better than mine to the point where I wanna know whats up. As far as I know, both are running the original tune from the factory and neither have been re-tuned. Overall, I get between 2-3 mpg better than her even when we drive alike. But lets face it, I want the power loss back. Mainly, I am wondering what could be causing this difference between the two seemingly identical minis. I am open for an suggestions as to what could be the problem.

Thanks for you help! :)

I wanted to mention that I just checked both minis for a sprint booster and neither car has one of these installed on them.

You could try resetting the ECU on your MINI so that it relearns your driving style.

Interesting. I'd like to hear some suggests to pick up the power as I kinda feel like mine takes some pedal to get going. But once its going it sure goes...

I did reset the ecu once. It did seem to run quite a bit better but within a day or two it reverted back to the normal way that it felt before the ecu reset. Although when I did reset it, the car was a bit more responsive at lower rpms.

You sound like you are describing what a tune does to the car. Better pedal and all. Maybe hers was tuned and they just returned the parts to stock when they sold it. That way you can't see any evidence, and they may not mention it at trade in.

Just a possibility that explains it.

It also can be she has a different SC pulley on it. That also makes a big difference in power band.

Some cars are just a bit healthier, and that may be what you feel, but the two above reasons are reasonable explainations.

I'll check for the pulley difference tonight when my wife gets home. As for the tune, im pretty sure there is no way to tell for sure whether or not hers is tuned and mine is not.

They might be running different factory software....
It is also possible that one car might have a sticky bypass valve....
some r53 did very in power quite a bit....most said this was due to quality control....this seemed to mostly disappear by 2005 (when the gearing was changed, the sc upgraded, and a more advanced ecu was installed) when most cars seemed to perform simerarly...the 2005+ cars have about 5+ more hp stock, but the gearing makes a big differance.

PS
It goes without saying that all scheduled mantaince has been done....
Plugs might be due...good time to do a compression check....

Not unless the car is plugged into the mini computer and reflashed....most of the tunes are pretty sealthy, but some might be able to tell....
I think many folks have a pulley and don't know it....there is a thread, nearly weekly where somebody removes an aftermarkrt pulley, and then says it was easy....just bolted on no tool needed!! Lol
The stock pulley is black, hot pressed on, no bolts. Aftermarket usually will have bolt holes, and be cnc machined (some of the supper early pullies were hot pressed...wow...i'm dating myself in the r53 community).

have you checked the boost using a gauge to see if yours may have a boost leak somewhere?

If the only difference between the two are the intakes, then that's probably why there's a difference. Try switching your intake onto your wife's car and see what happens. The crappy KN filter's probably plugged or too full of oil.

Detroit Tuned bypass valve? The DT valve looks stock (because its a modified OEM unit) and people often report symptoms like theese that the OP decribes: More power, Quicker responce, A few less MPG.
Atleast this is what it sounds like to me.:thumbsup:

Definately check the K&N. They're easy to overoil. And, if it's like newer K&Ns, it may have an extra foam cover over the main air filter. If it does, remove it and see what happens. K&N used to tell everyone how well their filters filtered dirt but also flowed more air at the same time. Really, neither was all that true. In the past few years, I've seen more K&Ns with the added foam filter. Why would they add this to a filter that already "does a good job of filtering"? (Hmmm, maybe they were full of BS all these years??) Anyway, I've seen numer of cases where the added filter really choked down the intake of an engine and the removal of that foam cover over the filter made a world of difference.

Frankly, I'd just go back to the stock air filter.