So I know this is commen question but in general how much hp gains do you get when adding an exhaust?

 

maybe up to 4hp on otherwise stock mcs, nothing that you can feel the difference, mostly for noise. more if you have a pulley. more if you go header back. the biggest difference is the weight savings. the stock muffer and resonator are about 75 lbs, whereas most cat backs are under 40

 

Ok cool I didn't think there was much difference I just wanna figure out what my next upgrade was going to buy. Currently I have 16% pulley CAI cooler plugs---> I was thinking about either upgrading injectors, Methanol/water injection or exhaust,

 

Don't waste your money on injectors....the stock 340cc injectors are good for up to around 200hp and some push them over that. If you already have a pulley and CAI, unless you want your car a little louder (exhaust).....I would start looking at brakes and suspension mods. You can look at a custom tune, but the money to HP ratio is tough to swallow.

A mini is never going to be a big HP car...unless you spend a TON of money on the motor. Look at sway bars, better brakes, better tires, lowering springs...stuff like that.

 

if you have the CAI and the pulley already the exhaust will be the next restrictive thing. (catback atleast). the header can flow pretty well until you get a cam. but the stock cat can flow 400hp.


with injectors you need a tune. a un tuned 380cc injector will actually run richer under WOT and give you less HP. and the mini wont run with 440's or 550's without a tune.


injectors are only needed when you start messing with the topend of the motor. aka big valve head/portpolish/cam

 

^Much good advice, here^.

If you're getting an exhaust, get it for the sound, weight and quality. I recommend the Milltek. If you make a couple of WHP with it, all the better.

 

Right now im not super concerned with great handling since I'm basically just spend most my time on the highway. This is the reason why I wanted to just add a few more horsepower without putting too much into it as far as money; I know it will never have the hp that a v8 can achieve. Up until last year I used to have 1970 ford maverick with a 302 sbf motor putting out 350 hp rw but the mini is a blast to drive when comparing it to other similar cars. Getting back on track basically right now I plan on only doing one upgrade at this time so I wanna make sure I do the most beneficial upgrade for hp gain.

 

the r53 will RUN with bigger injectors but it wont be happy and will be at like a 9:1 AFR on 550cc with a 17% pulley.

you need a tune. i had mine in my car for a week before going to helix and getting jan to tune it while he was there. since then i have seen a mpg improvement even when compared to a bone stock r53.

 

the biggest gains per dollar are: 1.) Pulley 2.) Cam 3.) Free Flow filter, not CAI, but CAIs sound amazing) 4.) Exhaust


in that order without getting a new head.

 

I would insert a custom tune at number 2 or at worst 3 in your list, Salty. If you're doing a cam, you really should tune it.

 

I agree, but I was going cost for dollar. and I should have added the tune at 2 or 3. or do them all at the same time, then the tune prolly is the highest hp per dollar haha

 

Ok this brings me to my second question then If i get a tune and eventually get a exhaust and methanol injection kit I shouldn't have any reason to retune since a both exhaust and methanol injection shouldn't have any direct effect on engine performance, as far as the tune is concerned.

 

Also getting a tune For my car was of course something that I had considered but Im not sure What options are available for my area (I live near Baltimore). Sorry for all the questions you have probably heard before but I need to get all my facts together before Pulling the trigger on any modifications, So far I have been extremely lucky with spending probably only spent 300 or so on the few modes that I do have and want to keep that way.

 

as for tuning, you have mynes and rmw, they are the only that can do remote tuning. waymotorworks I think you have to send them your ECU and they can flash it. that's pretty much it for tunes.


no need for a tune with a catback, but if you have a header back, the tune can be slightly changed. also with meth, you can choose to be dependent on it or not. if not tuned you never have to worry about it. if you are tuned for meth, youll always need it

 

Are there any aftermarket cams out there that are good for a daily driver street car? Every time I hear about someone swapping cams....sure they have a little more HP once you get the engine wrapped out and the rpm's are over 4000+ rpms.....but anything under that, most dyno graphs show that the motor actually looses low RPM HP and TQ.....what you need for a fun daily driver. What good is a daily driver car if you don't have any power down low.

Not sure I would call a cam one of the top three bangs for the buck. Sure...if it's a track car, but not for a street car.

 

Great point.

 

You'll probably get the most enjoyment out of something like a rear sway bar than the other things you are considering. Having said that, I love having a sportier sounding exhaust. I'd buy an exhaust for its sound alone over the couple extra horsepower you might get from a cam or injectors and tune. Sure, an exhaust is a pretty poor investment if all you are after is power, but what do you enjoy more? 0.1 or 0.2 seconds off your 0-60, or having a car that sounds bad ***?

 

Yes I agree a cam is not part of the top list of modifications you may get five to 10 hp from it but for every 1 hp you'll be spending like $80 dollars around for the 500 bucks for cam set

 

Exhaust really steps up the feeling of the r53, well worth it. A cam will be nice up top but for a dd I wouldn't bother.

 

the NS1 and RMW street cam have more of a focus on midrange than topend. shouldn't sacrifice low end. theres also an adjustable cam gear from thumper so you can orientate is as such.


I agree that you don't want a super aggressive cam, unless you track, but I always play in the midrange, 3400-5000 where peak torque is