93egSLEEPER

I've been doing some research on small ways to improve ET's which led me down the path of skinnies on the rear. Obviously all the "real/fast" cars/teams run them, but is this justifiable for a weekend racer/daily street car? I'm curious if anyone has any testing or numbers to compare running skinnies vs a set of stock tires/wheels on the back. The first obvious advantage is weight, but does it make THAT much of a difference? Looking at a test and tune/daily car is spending $700 on a set worth it? All you strip vets teach me a thing or two.

I took my new build out for the first time w/ less that desirable conditions (120+ track temps, 95ish ambient temps and high humidity). The tune was way rich (seeing 10.8-11.3 AFRs) and I assume was being compromised by the heat on the track. Pulled a 13.4 @ 100 w/ 1.9 60's in my full body/interior eg coupe weighing 2450 w/ me in it. Car made 220whp on a known stingy dyno (reads 8-10% lower than most in the area) and I was expecting traps in the 105-107 range.

Anyways enough small talk, I'll get the tune redialed, but is there really any significant gain w/ running skinnies? Say .2 or more in the ET? Looking at future options/upgrades as I drive the car and want to get quicker and quicker.

Thanks

Dark_Teg

The only reason to get them is to run bias plies on the the front and back. You will see basically no gain as far as ET's go.

93egSLEEPER

Thank you for the input sir. Much appreciated

Turbo-LS

iTrader: (4)

Well it's weight reduction and a lot of it unless your street wheels are Grams then they're much heavier than a set of skinnies. 100lbs is a tenth roughly
That being said you can get spare wheels from an RX7 with adapters cheap there are other cars with nice skinny spare wheels and use adapters to save on the funding part

Twenty47

I never knew weight reduction and rolling resistance reduction would not help ET's. good to know

SPOOLINmatt

got me too^

XRacerX

iTrader: (3)

My heavy *** All motor 81.5mm Ls/v EJ1 coupe full interior 2400 lbs with me in it. Of course am looking for less rolling restistance and drilled rear bumper as well. Every lil thing can help.

Project_EK

iTrader: (1)

Ill be honest with you guys, the best most cost effective way to go fast with that power range is to lighten up the car!

93egSLEEPER

I appreciate all the input guys. I like the idea of skinnies for weight reduction, and rolling resistance is another angle I didn't put much thought into. After reading up on this some more, some domestic guys were reporting as much as .3-.4 difference just by running skinnies on the front, I'm sure wind resistance plays a roll with them as well.

I'm going to do some searching to see what I can find on a budget until I decide to pull the trigger on a real set. Or maybe I should stop being a cheap *** and just buy some

I am waiting to hear about a promotion at work. Should I get it I'll be getting a company vehicle and this car will almost never see the road (I use it as a commuter 3 to 4 days a week right now...12mpg in my truck just doesn't cut it) If that happens I plan on gutting it and going full on track car with it to see how quick I can get it to go for a fairly basic B20V build. I think I can get the weight down to 2200 w/ me in it pretty easy (I'm 225). From there, its learning to drive it and tuning.

Brings me to another question. I'm running 23" slicks right now, might throw on a set of 22's to see if it helps my 60's. What size rear tire do you run? Match the front? Or does it matter?

Project_EK

iTrader: (1)

If u can pass the traps in 4th gear with the 22s without bouncing off the limiter, they will be a better option!

93egSLEEPER

With my rev limit/gearing setup right now I'll have to trap above 115 to hit the rev limiter in 4th on 22's. I don't foresee that happening in the near future. As it sits right now I'm hoping to see traps in the 105 area

PSI GUY

iTrader: (2)

We run a ghetto setup, VX wheels on the back with 155/80/13s on them. Paid 30 bucks a tire brand new....lol. Skinnies and tires would run way more which can go into suspension, etc.

93egSLEEPER

^^^ GOOD POINTER. I'll see what I can find locally. I feel like my suspension is setup pretty decent for now. 12k front springs and 10k rear springs. I turn the dampning to full stiff on the rear and the car launches pretty solid. Not much dump in the rear.

PSI GUY

iTrader: (2)

We have TEIN HAs, car was a circuit car before which is probably not the best setup but seems to work okay. Maybe next year we will invest in some good stuff.

Turbo-LS

iTrader: (4)

Spring rates are way to high for both front and rear of that car. this is an old method of thinking heavy heavy springs. Better to let the shock do the suspension control and the springs just support the weight of the car. Corner weigh it and see what you have for weight and pick springs from there.

Dark_Teg

I had 200+ runs on My N/A CRX best time of a 8.66. Went from Metegi Traklites to skinnies for 20+ passes in Fall weather and my best time was still a 8.66. Excuse me for sharing my real world experience with a car that runs in the same ET range as the OP.

I am running them on my new build mainly to have bias plies all around cause I feel it would be safer at 130mph trap speeds in the 1/4. I understand in a midst of a perfect pass you may realize some fraction of a tenth drop in ET. I just think FWD cars are too inconsistent to notice such small gains.

93egSLEEPER

Thanks for the post. I'll look into it. I set the car up to be a daily I could go play with in the corners and still take to the track. Now that it is most likely turning into more of a track (drag) car I'll start to set it up that way. I have GC coils on Koni yellows so I can order new spring rates when all is said and done.

When you say corner balance and pick springs how do the two coincide?

I appreciate your honest, real-life answer. I agree FWD cars are typically not consistent enough to worry about .1 of and ET unless its a car that is racing for money all the time competitively. I come from the domestic world of things as well and understand what consistent is. Definitely not my honda lol.

Thanks

AZ_CIVIC

iTrader: (1)

Putting your car on scales allows you to weigh each corner of the car. How this relates to spring rate choice is you pick a spring rate based on the outcome. For example if you car is around 750 pounds each corner up front and around 450 each corner in the back, you would order a set of springs with a spring rate of 750 for the front and 450 for the rears.

You want to get spring rates based off of the weight of the car and the best way to do it is putting your car on scales to get a reading of each corner.

Now, once you have done that and if you have coilovers you can even adjust the height of each corner to try and get your weight balanced. I also took my car to the alignment shop and had them do a drag alignment.

93egSLEEPER

Got it. Makes perfect sense. I may be stripping the car down in the near future, so I'll wait so do the corner balancing and springs until I have it at a trim I know its going to stay at. Right now it has 600# springs up front and 500# springs in the rear.

Thanks for the info

Here is my project: