Mr. dB, or anyone else that knows engines

[RottenWillow]

What mods are most likely to improve the power curve of an engine? I dont just mean make more power, but make more power sooner, i.e lower rpms.

here's the deal: My fiance is now driving the RSX, and I've bought an '04 Mazda 6s. Horsepower is ok, but it only makes 192ctq @ 5000rpm. the power curve is flat as hell until 3800, then it zips pretty good. I really want to build torque more quickly, but a simple bolt-on CAI wont do that. A turbo is out of the question since I want to keep my warranty intact.
Any suggestions?

 

[pintoca]

change to engine to a diesel... can't beat the torque on that.

on a side note, mmmmhmmmm, gotta love forced induction

 

[sublime35]

personally I would get a Short Ram intake over Cold Air. I would go and get yourself a better torque converter(if its and automatic) or a customized converter if its a manual trans. You could also look into an exhaust, new throttle body, or a new Pulley system.

 

[wootoom]

ya get a real car with real HP and TQ

 

[Buddy_Christ]

Intake/Exhaust will do quite a bit for the power curve if it's done right. High flow exhaust will make high rpm hp better, where a more restrictive exhaust will help low end torque (high flow exhaust will kill low end power). Different intake set-ups (and we're not talking a CAI or short ram here, we're talking about the actual intake itself) will give you different power curves too. You'll probably have to hit up a Mazda board to see what's out there to make more power where you want it.

I find it kind of odd that it peaks tq at 5K rpm and peaks hp at 6300rpm. I would expect a V6 to peak torque a little earlier than that, maybe 4K or 4500 rpm. That's actually a pretty narrow powerband IMO. However, you're starting to feel the power build at 3800rpm and it should continue to pull strong until redline, which isn't too bad, you've just got to get it up to 3800rpm first.

Intake, exhaust, chip/flash the computer, maybe injectors as well. You might have to sacrifice a little bit of power in the top end to gain a little in the low end, you might not. Different combos of aftermarket parts will give you different results.


On a side note, I just want to say that I love you. A woman that wants to make more usable power out of her car makes my pierced penis hard. Sorry about that, I was just being honest.

 

[Whiskey]

crak600, i've always seen and been told the more exhaust flow the more torque at lower rpm and more hp overall. Look at any wedsite about headers. Also a performance catalytic converter... or get your computer reprogramed and take off the cat.... but would void your warranty.

I have headers, performance catalytic converter, NO muffler with 3" tubing..... then again I also have a 360 in my 'ol dodge as well.

I don't know squat about the RSX, so maybe the exhaust option is different from what a bigger v8 would use.

Don't listen to me ;-)

Whiskey

 

[SoreArms]

stop posting car threads just to make a point for your car forum.

 

[Buddy_Christ]

crak600, i've always seen and been told the more exhaust flow the more torque at lower rpm and more hp overall. Look at any wedsite about headers. Also a performance catalytic converter... or get your computer reprogramed and take off the cat.... but would void your warranty.

I have headers, performance catalytic converter, NO muffler with 3" tubing..... then again I also have a 360 in my 'ol dodge as well.

I don't know squat about the RSX, so maybe the exhaust option is different from what a bigger v8 would use.

Don't listen to me ;-)

Whiskey

I've always been told the opposite and you can actually see it on a lot of cars with high flow exhausts, like when you see a car with a fart cannon coming off a stop sign. It'll be loud as shit in the lower rpms and will start moving really slow while the rpms are going up. Then it'll suddenly start to move faster as the rpms get up higher.

I've also noticed on my own cars with V6s and V8s (when exhaust parts have rusted off) that they lose low end power due to the lack of backpressure in the low RPMS. They'll rev through it quicker but they don't seem to get going as fast.

I've been in (unfortunately havn't driven) muscle cars with different exhaust setups. The ones with more restrictive exhaust start pulling strong right away where the looser ones don't. On some it's a simple matter of muffler placement. Some guys throw the mufflers on as soon as they can after the end of the headers for a really snappy (and more restrictive) exhaust, where other guys put them further back for more rumble (and less restriction).

My buddy unbolted the exhaust on his Chevelle one night and we took a drive with it running open headers. Loud as fuck and pulled like a bat out of hell in the high rpm but lost a lot of low end power.

You can do headers and still have an exhaust that will aid low end power and change the tq and hp curves where you want them. It's a matter of playing around with different setups, or even better, looking at the results others have gotten and doing one setup right away.

And one must always remember - when changing the exhaust, the intake end of the engine MUST be adjusted for it. If you're running too loose of an exhaust and you havn't compensated for it in the intake, you'll run the engine lean as hell, as there will be less backpressure and it will allow more air/fuel to slip through when the intake and exhaust valves overlap.

 

[Mr. dB]

I'm the wrong guy to ask, I don't know shit about tuning.

BUT, it seems to me that virtually all bolt-on performance mods will increase HP at the expense of torque, except maybe a supercharger which can add power across the RPM range.

Maybe one of those companies that do custom-mapped chip mods could do something?

 

[RottenWillow]

Intake/Exhaust will do quite a bit for the power curve if it's done right. High flow exhaust will make high rpm hp better, where a more restrictive exhaust will help low end torque (high flow exhaust will kill low end power). Different intake set-ups (and we're not talking a CAI or short ram here, we're talking about the actual intake itself) will give you different power curves too. You'll probably have to hit up a Mazda board to see what's out there to make more power where you want it.

I find it kind of odd that it peaks tq at 5K rpm and peaks hp at 6300rpm. I would expect a V6 to peak torque a little earlier than that, maybe 4K or 4500 rpm. That's actually a pretty narrow powerband IMO. However, you're starting to feel the power build at 3800rpm and it should continue to pull strong until redline, which isn't too bad, you've just got to get it up to 3800rpm first.

Intake, exhaust, chip/flash the computer, maybe injectors as well. You might have to sacrifice a little bit of power in the top end to gain a little in the low end, you might not. Different combos of aftermarket parts will give you different results.


On a side note, I just want to say that I love you. A woman that wants to make more usable power out of her car makes my pierced penis hard. Sorry about that, I was just being honest.

I would be more than willing to give up a little top end to get more low end. I want to make the power band a lot steeper, but flatter out at high RPM. That narrow power band it's got now annoys the HELL out of me....it's a fair amount of power, but not very usable.

The power chip you and Mr. dB are suggesting might be a good, easy way to change the power curve.

anyway I did find a mazda board like what you mentioned. Strictly about the Mazda 6 if you can believe that. I'll check that place out to see what I (read: my fiance) can do to tweak the car.

 

[Mr. dB]

If you wanted torque you shoulda bought a VW or Audi.

 

[Big Rick Rock]

Wait wait wait.... Fiance? when did this happen?


Last I remember you had a BF you didn't even like that much.




-BRR

 

[Buddy_Christ]

I would be more than willing to give up a little top end to get more low end. I want to make the power band a lot steeper, but flatter out at high RPM. That narrow power band it's got now annoys the HELL out of me....it's a fair amount of power, but not very usable.

The power chip you and Mr. dB are suggesting might be a good, easy way to change the power curve.

anyway I did find a mazda board like what you mentioned. Strictly about the Mazda 6 if you can believe that. I'll check that place out to see what I (read: my fiance) can do to tweak the car.

Intake(s), exhaust, possibly injectors, fuel remap are probably all your best bet to get the torque a bit lower in the rpm range and the powerband wider. I wouldn't go all out and throw cams in it though, that'd be kind of overkill for a daily driver and might void warranty.

Any questions shoot me links to threads over there and I'll give a read through, see if I can make sense of what they're doing. The best thing for you to see right now would be a dyno run of the car bone stock and then see dyno runs after mods. Always best to see those runs on other people's cars so you can figure out what you want to do.

It gets tricky without dyno numbers, as it might feel like you've gained power when in actuality you lost power. The only reason it'd feel like you gained power is because when the engine starts making power, it just came up from a serious lull in the rpm range.

And remember, no fart cannons.

If you and the boyfriend ever break up, make sure I'm the first to know, ok?

 

[RottenWillow]

If you wanted torque you shoulda bought a VW or Audi.

VW's are ugly and Audi's too pricey. but if torque was the primary selling point I would've gone with the Saab 9-3 Linear.....195@3000rpm. (If the Arc were within my price range I would've gotten it)

I loved the 6s handling, looks, and the price was right. I just need to cook it up a little, and I'll be a happy girl.