RealLiveMD

iTrader: (1)

I'm bouncing off rev limiter set at 6800 with stock tires at about 100 ft from traps. Is this righ? Is it because I'm spinning too much. I thought 3.90s could do 129. I know for a fact the size of the gears and rev limiter. Is something wrong with my rebuilt tranny?

guppymech

iTrader: (7)

Somethings not right, with your combo at that rpm you should be doing 130 or so mph using the http://f-body.org/gears/ gear calculator. Sounds like you're thinking along the right track with the tranny. Maybe try posting in the Auto Trans and Drag Racing sections too.

RealLiveMD

iTrader: (1)

It's an m6

guppymech

iTrader: (7)

Since you don't have any sig info I took a guess. With the manual there is only two things it could be, 1. you clutch is slipping or 2. your rev limiter is not set where you think it is. I believe the stock rev limiter setting for a ls1 is 61xx and when I plug that rpm into the calculator it comes up with.......119 mph. Fourth gear in the T56 is 1:1 I don't see how your trans shop could screw that up. Are you running 2k @ 40 mph in 4th? If that rpm/speed is correct = 1:1 ratio.

25thhawk

iTrader: (3)

4.30's in my car, traps 119 at 6400 with a 26 in et drag. Something isn't right.

RealLiveMD

iTrader: (1)

I have up tuners scanner. Rev limiter def at 6800. Tires are 275/40/17. Tranny was rebuilt by t56 rebuilds back in the day. Car traps. 113 off gas. And runs out of gear on spray. Should trap higher because it suppose to make 425/415Don't know what's going on. I ran. About 1O time

RealLiveMD

iTrader: (1)

I watched the 390s go in from the box

25thhawk

iTrader: (3)

I would double check the gears, just to rule it out. Sometimes things get boxed wrong. Other than that I would say that you have clutch or hydraulics issues. Does the clutch pedal stick to the floor down track? What gears are you spraying in?

RealLiveMD

iTrader: (1)

Tried spraying first and second. Same resultsq. It's the craziest thing. I double checked the gears before install this is my third set of gears. I know what they look like. 4.11 r much smaller. I can't figure this out

01ssreda4

iTrader: (96)

Can you give us some rpm/speed samples while cruising. This would help us confirm your actual gear ratio. Also, why don't you just double check them? Spinning the DS with the rear wheels up in the air is a good way to 100% confirm.

RealLiveMD

iTrader: (1)

The serpentine just broke. I'm assuming it was slipping. I'm not sure why that made the car over rev but I just hit 129 on the undisclosed racetrack in 4th.

25thhawk

iTrader: (3)

I love weird problems, that have solutions that make no sense. I got no idea why the belt would cause that.

HioSSilver

iTrader: (8)

I have trapped up to 130 with 3.90's with my limiter @ 7k. Sounds like a odd problem. I have same height tire as you.

RealLiveMD

iTrader: (1)

I'll check in am but all of a sudden my fuel injectors were maxed. They use to be at 80 percent but that was with a broken spring. I'm thinking the fuel pump may not have been getting enough amps. Will verify in am. Oddly though car feels slower on takeoff now.

25thhawk

iTrader: (3)

ok, i could see that making sense if you were low on voltage. Maybe not enough fuel pressure or hot enough spark. It might act like you hit the rev limiter, but your rpm shouldnt have been anywhere near it.

RealLiveMD

iTrader: (1)

Thread resurrected. I now have 4.11 in strange s60. Still max trap is 114@6800 bouncing off limiter. I've called t56 rebuilds. They say they don't see how they could have messed up the ratio. Also for sure, my limiter is at 6800. On the hp tuners I don't see a sudden jump in. Rpm as if the clutch is slipping. This is so annoying.

guppymech

iTrader: (7)

4.11s with 25.6 tire@114mph=6100rpm. How are your valve springs? Are you confusing the engine not accelerating because of valve float with your rev limiter? You should be going 127mph at 6800 rpm. FYI the stock tachometers are not reliable at high rpm, they can be off hundreds of rpm.

RealLiveMD

iTrader: (1)

Over the two years of this thread. I've had 3 sets of valve springs. Comp927s. Now I have prc .675 lifts which by the way cost me 1mph. The 4.11 gear swap from 3.90 dropped me to 114 from 118. I know the stock tach is off but the hp tuner and hsw nitrous switch are lined up with 6800. I can even feel when I do spray my nitrous cuts off at 6300. Furthermore to run 124 I have to be deep into fifth when I'm on nitrous. It's frustrating it took 4 years to figure out the vibrations on this thing but no one has ever figured out this low trap. For eg. With my old set up that had 410 rwhp on whichever is the good dyno. This car would only trap about 111. I'm actually a good driver and have killed tons of cars on the street/strip
but its from driving not traps.

01ssreda4

iTrader: (96)

What you are describing is physically impossible. Motor rpm (known), clutch slip (no evidence of), trans and rear ratios accounted for, tire height (fixed) = your mph vs. your rpm. That's it, if it doesn't add up, its one of the above....obviously motor rpm and speed you are using equipment to measure so that must be evaluated in the process. We cannot help you any further honestly. This HAS to be something simple, because there isn't much to the process of mph vs. speed.

RealLiveMD

iTrader: (1)

Ok guys I know I'm beating a dead horse. i've yet to have anyone with knowledge of internals of trannies tell me if somehow its possible to mess up the gear ratio. That's honestly the only thing that I can think that would make since. To test clutch this am. I did 30 mph on a hill and put in 6th and floored. no clutch slip. rpms in 2nd gear at 40 are exactly 4000 to 4100 in 4th gear at 40mph rpms are 2125 with hsw tach and 2100 on dash. the rear gear changes and complete rear swap takes the rear out of the equation. the clutch seems ok. I have had 3 springs so valve float shouldn;t be it and I have over 40 time slips