Not sure if this is the proper forum, but I'll try anyhow.

So if you start with a base cooper (115hp), how much does the average driver need to increase that to notice a differece? Will a small 5HP change really have any noticable impact or do you need to get closer to a 20% increase to really tell a difference?

I've done some searches, but get a bazillion not related threads. Just curious, thanks in advance!

Mark

 

Well, you're going to have to throw torque into the equation too. Depending on how you drive, you may notice an increase in torque much, much more than an increase in Horsepower.

 

When I modded my MC, I first did the intake, only increasing a few hp. It wasnt very noticeable, but seemed slightly there. It may have been that the sound was a little different so I was imagining it, or even that I was driving harder to look for it.

Then with a cat back exhaust, the same thing but more noticeable. Alot louder so it sounds like more hp, and noticeable. And then I was driving a lot harder with that nice growl egging my on to step on it. Could of still just been my imagination though, because of the sound difference and the fact that you are driving harder and looking for the increase. Felt like more torque though, better response.

If you don't drive aggressively, however, you would barely notice if you did the intake and exhaust. It was definately more fun though afterwards, and the tone was much better.

 

depending how sensitive your "butt dyno" is.......I can tell (or think I can) 5 hp with 2# of torque....ala the new Alta crank pulley made a diff on my "butt dyno"

 

I would say that 10% is noticeable. . .

If I was going to modify a Cooper, I'd spend more money on improving suspension, brakes, and light weight wheels before I'd bother with any horsepower improvements.

 

I disagree, and I did modify a Cooper. Mine had the sports package, so it may be different, but with only 115 hp I found the stock suspension to be great (better than any other stock suspension I had previously had). I realize that the suspension is important if you have an MCS or are racing, but for street use on a MC I didnt feel suspension was a priority. Just my opinion though.

Same with brakes. I did a nice brake upgrade but dont really appreciate it as much as the perfomance upgrades. Once again, I dont race and try not to brake hard on the street for safety reasons, so didnt matter much to me (though when you do need a brake job you can save money and get an upgrade by not going to the dealer).

Light weight wheels will help and give some added style, this I do agree with.

I started with the intake and exhaust, and am glad that I did. They just seem like they are more fun than suspension and brakes to me. Especially that growl. To each his own though. You are however only going to get about a 10% increase in horsepower this way for around a grand, when a grand can get you twice that with the MCS. Well have fun whatever you do.

 

I have an MC with the sports suspension (not plus)

First mod I did was a 18mm H&R rear sway bar. The car understeers a lot less, and will slide the rear if I lift off in the middle of a hard corner, or if I trail brake into a corner. Its very safe and worry free for street driving

Second mod I did was the Remus Dual tip exhaust, I don't think it added any HP at all, it sure sounds nice though!

Another mod thats very popular with MC owners is an intake. Personally I won't do it. Most of the intakes sucks hot air from the engine bay, not my cup of tea. Also there are reports out there about K&N filters sucking in more dirt than the stock paper filter. Sure K&N say their filters are better than OEM, but I still have doubts, and with just 2-3hp to gain, I'd rather not risk it.

For a MC I think money is better spent on improving the suspension and the looks

 

I'll throw in my $.02... I dyno'd mine totally stock and got 106.4 at the wheels. I added the BMP/Promini intake, Borla cat-back, and MTH software and got a best pull of 112 at the wheels - torque was slightly improved in the low-mid range.

I spent somewhere around $800 for the parts... Not that great, IMHO. I could tell the difference, especially when it was hot out. When it was cool out, though, the difference was far less noticeable.

Now, suspension, that's where you get major bang-for-the-buck on the MC.

I autocross, and this year I am running one class higher than I was last year. This year, I've been competing against a modded MCS and many other more powerful cars. I won the first 4 of 9 events handily, as the MCS driver was learning his car. As he learned, he tweaked the suspension, adding H&R springs and a rear swaybar, and then slapped on Azenis. Then, I started losing by 1-2 seconds each time for the next 3 events and it got old. Drivers are about equal - meaning we post similar and consistent times run-to-run, session-to-session.

I already had the aforementioned performance parts, as well as H&R springs, 19mm H&R rear swaybar, and Bilstein SP struts. I was also running Azenis.

So, to save on mod points, OFF went the intake and MTH software, the stock airbox went back in with a drop-in Green filter. I left the Borla on, mainly because I like the sound! I added Ireland camber plates up front and K-Mac adjustable camber bushings on the stock rear lower control arms. Dialed in the suspension (-2.25 degrees of camber up front, slight toe out, -1.2 out back, 0 toe) and then slapped on Michelin Pilot Sport Cups. I ended up 5-6 seconds faster than the MCS at the last event and broke into the top 10 in the raw times. My previous best times were down around 24-25th fastest in fields of 60-80 cars.

Had I been stuck with the Azenis, I still think it'd still be 3 seconds faster around the course than the MCS, given equal driving ability. Now, if he had the same setup, he'd be faster - BUT, he can't stay in the same class with the same mods!

So, IMHO, as others have said - on the MC, you get more performance from suspension, wheel/tire and braking upgrades than you do from go-fast goodies. Sure, the MCS and other cars may walk you on the straights, but you'll maintain more speed in the corners and have higher exit speeds if you dial in the suspension and have a great set of tires. Drivers being equal, you can pretty much hang with many, many cars this way whether it be autocross, on the track OR in the twisties on the street. Especially when it gets tighter and hp isn't necessarily as much of a factor...

Cost for the suspension was $600 for struts, $200 for springs, $180 for the swaybar, $270 for the camber plates and $270 for the camber bushings.

Short of spending major bucks on a new head, cam, throttle body and all the other mentioned parts, you're simply not going to beat a good suspension setup. In a straight line, maybe - but what fun is that?

 

Thank you all for the replies!!! Lots of good information and as usual, no one correct answer for everyone. I don't expect to make any changes until the spring so I still have lots of time for planning/procrastinating/re-planning...


Thanks again