Stock my car dynoed 297/309 (@ about 42K miles). After adding SLP lid, cutout and 20K miles, dynoed it at 307/313 yesterday.

I guess it is not too bad for a mostly stock car, but I was still expecing a bit more out of it.

On two pulls out of three it hit the speed limiter while still pulling, so I guess there are still a few ponies somewhere. I guess it's time to start thinking about getting rid of the 2.73's and getting a set of 3.42's, or something...

I guess the gas mileage wouldn't get affected too much...

TS

 

good deal. i have 3.23 in my 00 formy. i went from 291/296 with the SLP airlid to 303/309 opening the cutout. that'll give you an idea of how much the gears will cost you in power.

 

first step would be to get rid of that stupid limiter...with 2.73s you have a ton of RPM left in third thats above the 118 mph limit. my car topped out 3rd around 130 mph with 3.42s. i don't think you could be making peak power that low. Also, your dyno numbers would be higher if the dyno tech had locked you converter. you'd probably gain another 10 hp or even on the stock converter...on my slippy high stall, i dynoed 321 unlocked and 341 locked.

 

I guess at least on mine the speed limiter is at 160, though, since that is where it goes before starting to cut off.

One of the reasons why I was thinking about the gears is also getting off the line faster at the track.

 

wait so the car was doing 160 mph on the dyno????? i dont see that happening...are you sure you weren't hitting the rev limiter and not the speed limiter...i don't mean to ask overly simple questions but i've never seen a car do 160 on the dyno in 3rd gear....

BTW: 3.42s are an excellent gear for an automatic

 

That's what the screen said. Not sure how accurate that is, of course.

I think he was running it in 4th. The rpm's were pretty close to redline, too but it hit the speedlimiter first, though.

 

both my cars only hit 135 @ 6000 rpm in third gear. but, then again, my cars have 3.23 gears in them. using the formula to compute mph vs rpm, RPM = MPH x GR x 336 / TD, 160 mph comes to 5710 rpms. now add in some converter slippage and it'll be real close to 6k rpms.

MPH = 160
GR = 2.73
336 = magic number to make formula work
TD = 25.7 tire diameter of either 245/50-16 or 275/40-17

 

I have the 3.73's and it cost me $525.00 for gears, differential, and installation kit from SLP directly. plus another 200 to get them installed. Cost a bit more then some would like but we all know these big boy toys aint cheap.

 

As far as i know dyno's are almost always done in your 1:1 gear which would be 3rd on an auto 4th on a manual.

 

I just kept my 2.73s and Installed a midwest 3400 converter. I makes a night and day difference.. much more fun to drive and didnt really hurt gas mileage

 

thats correct....dynoing a car in overdrive is definitely not the right way to do it....your dyno tech didn't know what he was doing...

you would more than likely get different numbers if it was done correctly...

 

I guess the guys doing the runs would know how to do it... ***shrug***

 

they did it correctly. i just show rpm vs mph that it was possible to hit almost 160 at 5700 rpms. my 94 z28 with 2.73 gears didn't have the mph limiter in it either. because whoever ordered it originally put the z-rated tires on the checklist. was on the doortag. 245/50-zr16. now my 94 formula i had at the same time did have thelimiter. it came with 225/60-16 t rated tires. which are rated at 118mph. hence the mph limiter. it also had the 115 speedo. the z28 had the 150 speedo.

 

your car did have speed limiter....fuel cut off around 157 mph...162 in LS1s..

 

Get a converter and keep the 2.73s.