3.31 against a 3.55; The 3.31 was faster..

[fox1x]

Okay, so one of the guys that works out at the gym with me has a black '06 that looks EXACTLY like my '07. The ONLY differences in the cars are my window tint, SLP's, and I have 3.31's. We both have 5 speeds, 17 inch wheels, I mean these cars are identical. His car has 3.55's and I was asking if he had drivin' the 3.31's. He said he hadn't. I wanted the 3.55's but couldn't find one.

So, we were on our way home on a 4 lane divided highway around 60 mph. We decided to see how they would do against each other. I had the car in third at as best I could tell was exactly 60 on my car, he said he did the same. He honked three times, he got the slightest of the jump on me; but, I started pulling on him. Not super fast, and I would say more of a creeping on him. We tried it again and the same thing.

The last run we tried was a 4th gear run from 65. It produced almost identical results. By the time I had hit 95-100, I would say I was about 3/4 - 1 car length ahead.

I thought 3.55's were supposed to be better for performance. We both had full tanks of gas and we are 15 pounds of eash other weight wise. Maybe I'm thinking now that I don't want to get rid of the 3.31's? Any thoughts?

 

[ski]

I can think of 4 possible reasons:

1- Your car may be producing more power than his. Due to slight differences in manufacturing and assembly tolerances, identical engines will produce different max amounts of torque and hp. I've seen SAE corrected dyno readings that vary anywhere from 255-275 hp for stock manual S197's.

2- He may drive his car conservatively, and you may drive yours aggressively. This will store conservative timing and A/F values in his ECU's memory, while aggressive values will be stored in your car's ECU. Aggressive values produce higher hp.

3- Your SLP's may be helping your engine to output slightly higher hp.

4- His tires and wheels may be larger than yours, which will increase his car's rolling resistance, and reduce its acceleration.

 

[fox1x]

We both have 5 speeds, 17 inch wheels

I know it's not the tires. And I thought the SLP'seally didn't do much but add sound. I guess reason number one could be it.

 

[Pliskin]

Could I unplug my battery and get rid of my driving habits on my ECU so I can make it aggresive? I know you can normally but I have no idea with a saleen tune.

 

[ski]

Reason #2 can also be a factor.

 

[ski]

Could I unplug my battery and get rid of my driving habits on my ECU so I can make it aggresive? I know you can normally but I have no idea with a saleen tune.

It should be able to be done with any tune.

 

[fox1x]

I was talking to a guy at work about it today and he said at higher speeds a taller gear set will allow you to pull in a certain gear longer. He said 3.73's and 4.10's are great for the 1/4 mile, but for higher speeds a 3.31 will be better. Does this make sense?

 

[Pliskin]

With the 4.10s top speed goes down. Faster acceleration but it cant go as fast because the RPMs will be like 1 to 1 1/2k more.

 

[kooldawg6]

With the 4.10s in mine, it is very peppy when downshifting from O/D at 70+ and accelerates hard up until about 120. I stopped there as she was starting to run out of steam(didn't notice the RPMs). 3.31s vs 3.55s won't be much difference at all, so I believe it is all of 1, 2 & 3! Even if you nailed the gas a fraction of a second before him could have made all the difference if both cars are nearly identical.

 

[ranger04]

For sure, a higher gear (numerically lower) will give you more topend speed where as a lower gear (numerically higher) will give you better excelleration at the cost of some topend. With our roads in this country having set speed limits, excelleration would be more important than topend. Stop light to stop light is where it's at, 1/4 mile and so on unless your gonna run on Daytona.