Ls1 Top Speed?
 

Anyone know what the top speed is for my stock 99 z28?
Just curiuos (havent had time to drive out in the desert) YET:cool:

I have seen published numbers from 158-162 mph.
I cannot attest to that personally, I ran out of road at 140.

i have hit the 162 mph top speed limiter more than a few times in my '99 z/28 (a4, 3.23) with just a lid, maf, fra, and cat-back. it ran into the limiter pretty hard, so i'm sure that there was more to be had. i just had the pcm reprogrammed and the limiter has basically been disabled by setting it to 255 mph. i'm guessing my car will do close to 170. i'm currently working on upgrading my brakes. :)

jay
san francisco

if your tires were f1 from the factory then your limiter is around 158...if it cam with gsc or gs or enything other then f1s then top speed limiter is at 115

actually, that is not true. only the ss option had f1 tires (17" rims), and my z/28 came with the gs-c model on it's 16" rims and a 162 mph top-speed limiter programmed into the pcm from the factory. if the fbody came equiped with the rs-a goodyears, then it got the low top speed limit.

jay
san francisco

Jthomas just wondering what brakes you were considering to install?

GSC's, went well beyond 115 plenty of times ... ;)

i AGREE THE ORIGINAL BRAKES ARE LACKING , i HAD MINE UP TOO 110 FOR A BIT IN 5TH GEAR AND WHEN i APPLIED BRAKES FOR THE EXIT ....FAAAAADEEEE BIGTIME

oops caps off:D

-rototech drilled and slotted rotors front, stock rotors rear- all cryo-treated by 300 Below
-Bendix Ti semi-metalic pads front, stock pads rear
-goodridge 6-line braided steel hose kit w/ valvoline synthetic dot3/4 fluid.

i have everthing but the rotors back from 300 Below.

if that doesn't do it then i will upgrade to eradispeed rotors front and rear and whatever pads they suggest.

jay
san francisco

most issues with brake fade can be resolved with fresh brake fluid.

i have hauled my car down HARD from 150+ to around 50 before with fresh fluid and stock brakes with zero fade.

the main reason i am upgrading the brakes is because i want a more firm feel at the pedal and, with the cryo-treated rotors, minimal warpage.

jay
san francisco

That's not true either...if your car came with Eagle GA's (standard for '98-'01), then you got the 115 or so limiter. The RS-A, GS-C and F1's are all Z rated...so they got the 158-162 (whatever) limiter.

I did take my car to ~170 mph one time (had to calculate it by RPM, gearing, and tire size). I could feel the front end coming up some..it made me a little uncomfortable. I would rather do that in a vette.

I was racing an RX7..we were on I-35 at around 3:00 am. I beat the Rx7 and just kept going.

The car had a hypertech on it, and 4.10s! It may not have been able to pull as much of 6th gear as it did without those gears.

i hear people with 200mph speedos and boltons hitting 185 in 5th

...imeant zrated tires instead of f1 and non zrated tires=115mph limiter

I hit the 6200 RPM rev limiter in 5th with no speed limiter. I also have the 200 MPH gauges. I did this a couple times. It was always on the same road with a bit of a downward slop. the gauges said 187MPH. This was done on the german autobahn. 170 was pretty easy to hit on the flat also, it was just dificult to find a good clear bit of road to wind the car up that much.