bahamut

2002OZ,

Did you run your car stock w/ auto? Manual doesn't tag 18's, unless w/ bigger wheels.


I did do that with 19 lb 17" rims on... sooo I don't think that makes that much of a difference, but if someone contests that statement on my part I'll do the calculations to give you whether or not it does and by how much.
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I'm a firm believer that bigger wheels on cars less than 250 HP will have an adverse effect on dyno. It takes more effort to get larger rotational mass of bigger wheels to turn effectively.

Example of OZ: Dyno a lancer with 18's, Dyno a lancer with 15's, and finally Dyno with 13's. Guess who will have the highest HP/TQ rating. Certainly, not the 18's.

Butt Dyno on the road:

1) A lancer w/ 18's will be a literally a dog to drive trying to spring off the line.

2) A lancer w/ 15's will feel normal as expected.

3) A lancer w/ 13's will feel that it will sprint like crazy, but there is unstability issues due to the samller tires on a 2700 lbs car.

4) I would like to wonder about the ES guys using their stock wheel . . . their figures should be slightly off from the OZ. Well, I have time, I'll read the wheel size and edit my previous post.

rhyzin

iTrader: (1)

i believe so too. there was a 1.8 mirage owner with i/h/e and pulled only 90whp b/c they had 17" rims. definately thought he should've pulled more.

sdhotwn

iTrader: (2)

I don't know how much I agree or disagree.. I really need to simply do the calculations. I'll let you know when I get them done..

But I've also heard that rubber will often weigh more than rim when you get into the sizes. If you are running a lightweight alloy I'd easily see the spoke distance as weighing less than a reinforced sidewall... but who knows. I also have a hard time believing that 4 lbs difference in rim weight (my 19 lb 17's versus the 15 lb stockies) would matter much of anything as far as total loads the vehicle sees... but we'll see what the math says.

Later.

Steve

rhyzin

iTrader: (1)

i'm not all that good in the physics of things but, if you have larger rims with smaller profile tires, would the fact that most of the weight is now on the edge of the rim than in a smaller rim needing more torque? also the longer spokes would require more torque also? all those saturday morning cartoons say that a smaller wheel produces more torque.

i can see that a small rim with larger tires would be easier to spin while larger rims with longer spokes and a low profile tire would be easier to spin after it has started to roll due to the mass on it's outer edge.

sdhotwn

iTrader: (2)

keep in mind that the overall diameter of the wheel/tire combo is still the same. So it's overall weight and yes weight distribution, that matter.

The torque is constant, so that's a mute issue, that's determined by the engine. Then acceleration is determined by applied force (F=ma), so if your rim overall diameter is the same.. then so is your applied force (torque is ft-lbs, so device your output torque by wheel radius... about 10 or 11 inches from center to edge of tire) and you get the force at the contact patch. Since regardless of what rim etc you have on there you have the same radius if you size properly, and your torque output is fixed by the engine's ability, that would say that regardless of the wheel you have the same force.

But, that is negated somewhat by the fact that you have to accelerate the rotation of the rim as well as the mass of the vehicle. But a few extra lbs in the rim is quite negligible in comparison to the mass of the vehicle.

So without even doing the actual math it looks like the rim will matter very little. Certainly not 10-20 hp .

imapunkclaimer

iTrader: (29)

im dynoing my car with the piggyback and aem intake tomorrow morning. ill tell you how it does. its 5speed btw.
im guessing 120whp so lets see what i get.

rhyzin

iTrader: (1)

good luck

imapunkclaimer

iTrader: (29)

HP
115.5 @ 5700 RPMS
3rd Gear Pull

TQ
126.2 @ 3600 RPMS

There was a big dip of the torque at about 4k, but im getting that fixed by roadrace. hopefully i can see better results.

only mods: aem intake / roadrace piggyback
stock wheels stock clutch

rhyzin

iTrader: (1)

dynojet?

WADADLIG_OZ

iTrader: (9)

How is it that Roadrace is going to fix that dip? REtune the PB?

I hope this is not indicative of all the PB's. Oh yes and please let us know which kind of dyno you were on.

WADAD

cerfur

iTrader: (1)

will get mine dynoed in the next week or so wating for time but my mods are rmr intake, rrre header, rre test pipe, rmr axel back,and rre piggyback i dont have any idea what im going to put down

Static

iTrader: (1)

Anybody with 18"s race theirs yet? hehe kinda wondernig, my car doesnt really feel to much different with my new wheels, but i could be wrong... People should post 1/4 times here too! im interested in that...

rhyzin

iTrader: (1)

i dunno if that dip is fixable. if you look at 03lancer's dyno, the same dip is there and this was way back with the reflash.

WADADLIG_OZ

iTrader: (9)

exactly Rhyzin!!!
And to me that would explain why I think the car seems to be less potent when shifting at high revs. There is no doubt that lower rpm torque is improved. I think this is confirmation.

Anyway back on topic maybe that should be in the PB review thread.

I have my 1/4 mile times at the bottom of my signature. (stock rims with 205/60/15 tires)

I will be interested to see what kind of dyno IMAPUNKC used.

WADAD

And BTW could you please post a dyno sheet for us. When I did mine hp was still rising at 6k rpm but of course that's just before fuel cut and redline for us.

bahamut

Off the line sprint, IMO, weight isn't as much of an issue. It's the effort to spin the rotational mass. A C5 vette or Supra can easily spin 17's and 18's because of their use globs of TQ, but you put those same wheels on a Civic DX . . . the results can be real ugly. Maybe as slow as a BMW 318 w/ 16's.

Also, a stock G93 will dyno somewhere in the 90 HP range. W/ basic mods, the 17's will still probably kill the G93's power, unless w/ TC or NOS.