1990 iroc with and L98 G92 (3.27 rear) and the 700-r4 of course. in 3rd gear at WOT i can hit 110 at 5000 rpms. is this normal? i am running stock (245 50/16) tires and rims. i know i can go faster by letting the trans shift into 4th, but i was under the impression that i could go faster in 3rd gear....

 

Back when I had the stock 350 and 700r4 tranny, I had a cop buddy clock my car at top speed. My car clocked 158 mph.

I did have a bunch of bolt-ons on it at the time too though. (full msd ignition, ram-air, flowmaster cat-back, k&n's, and fresh tune up).

I sure with my new 355ci and T-56, I'm sure I could top out ALOT more mph now!

 

that was in 4th gear, correct?

 

i dunno 91Z...i think your cop buddy was pulling your chain...
if your ride was dead stock then i can see 148 with a tailwind....but 158 is in LS1 territory and the TPI just came make the power hi enough STOCK to get that fast...
the way your motor sits now is good for 165 easy

the stock TOP speed of a L98 was 145 or so...
the top speed of an LB9 G92 was 143....
i think motor trend did a test or maybe car and driver id ont remmber but i rmember those numbers...and i tested the LB9 number many times...and each time its 143-145.....
TPI makes peak HP@4,400 and at 143 mph the RPMS are right at 4,400...

no wonder COPS pull people over for speeding...there guns are 10mph to fast hahahhaha

 

i pinned my tach past the 145 line and my rpms kept goin. i say i hit 153 maybe a hair less. and this is with 4 people in my car. what a LB9

 

I have bone stock '91 Z28 L98, and just recently I did a top speed run.. I got to 145mph at that was about 5100 RPM's in 4th gear (700r4) after that the RPM's just won't climb anymore, there's not enough horsepower at that speed to go any faster. 150mph is probably obtainable, but the speedo only goes to 145mph, and who knows how accurate that is up there. I was also going up a slight incline when I did 145mph so if you had a safe decline in the road you could probably go faster. But even as heavy as our cars are they tend to get a little light when there is any gusts of wind. It's a big adrenaline rush I'll tell you that, but I did at 3:00 am on an empty Bypass, that is fairly new. I wouldn't go try and do stuff like that on any road becuase it takes a while from 135mph to 145mph, and you need to be on a road that you know, and a road that is paved smoothly.. you don't want to hit any bumps going that fast. I guess that's one of the major downfalls of a solid axle rear. And the major thing be careful of is other cars on the road... if your gonna try it, do it when no one else is driving.

Dave

 

163 mph in my 87 Vette when it was mostly stock with 500 rpms more to go.

 

what speed are you guys hitting in 3rd gear at WOT 5000 rpms??

 

at 5,000 you would probably see somewhere around 110 mph with 3.27 ratio and an auto.

 

Those of us with 3.73's and no over drive top out a bit sooner . Someday i want a car that traps 150 in the 1/4...

 

f-crazy -

actually his radar gun is correct. Keep in mind that I had pretty much all the of the bolt-on's already on the car, I think I had the SLP runners on the car at the time too. The needle went way past the 145 mph mark and needle sat on the trip meter button and stayed there for a bit once I started to slow down, so yea, I do believe I was going 158.

 

In my 1990 IROC-Z with WOT 4th gear shifting ... I was able to get to PAST 145mph on the speedo. Probably 147? This was with a fully upgraded LTR setup, stock heads, stock cam, stock exhaust manifolds and a catback. I gave up going faster because that speed was scary enough. However, it would have gone higher.

Tim

 

Yea, the SLP runners help out alot on top end. I've been alot faster than 158 in other cars, but at 150 + , it's a DAMN scary ride in my car (no suspension upgrades other than the STB and factory wonderbar). I can turn the wheel in either direction both ways a little at that speed and the car still goes straight!

I bet with my new combo and my 6-speed teamed up with my little stock G92 3.23 geared rear, I bet I could pull some HELLA top-speed!!

I will do ALL the suspension upgrades before I even think about pushing the car that hard again.