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3rd Gear Chirper
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Would post in Drive Train, but I figured it's general enough and would get more views here. Anyway, I was considering some 4.10 gears for my 97 Bird, and was disturbed by the thought of my top speed limiter kicking in during a 1/4 mile run. Would this happen or not...I think since driveline critical speed would be reached faster that there is a pretty decent chance of that happening around 90 MPH or so. If it makes any difference, here's what she's got (drivetrain) now, with more to come once she's paid off: JMod - Mark VIII TC - tranny cooler - manual/auto tcc control - stock 3.27 gears. I realoze that the speed limiter is there for a very good reason, but if it cuts in during my 1/4 mile pass, would unpluging the VSS and turbine speed sensors disable it? If so I would only make 1 pass like that, I don't have any intentions of throwing a u-joint.
 

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With a 4.10 gear and no chip you will be doing two things. Possibly hitting the rev limiter out of first gear, and you will hit the speed limiter at a much lower speed. I'm guessing you will bounce off the limiter before you cross the line and that sucks.
 

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Yea, I hit my speed limiter with 3.73 right at the end of the track, and was hitting the rev limiter also, so youre gonna need a chip/tune.

-Andrey
 

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Geek w/Gearhead Complex
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Would he need a shift kit so the shifts would come in soon enough?? I'm just visualizing the car reving up and the trans not shifting in time so, again, visualizing rev, comp tells trans to shift, before shift complete - rev limiter (loss of power), shift, car wakes back up.

Also he might hit his driveline limiter before the 1/4 is up? w/ 3.73s dont they cut at 87mph?
 

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I had this problem and my solution was a speedo disconnect switch ,as for ruining into rev limiter that depends on how fast your car is as well.
 

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Yea, a shift kit will eliminate hitting the rev limiter, but the speed limiter will still be a problem. I suggest a shift kit, driveshaft, and chip/tune. In that order.

-Andrey
 

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Your speed limited would hit at 84 MPH with 4.10s in a factory 3.27 car. You'd definitely hit it. If you do the j-mod when you do the 4.10's you won't have to worry about bouncing the rev limiter on shifts though.
 

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Yep, 84/85mph is what you should expect. Also will shift sooner when not at WOT.
I wouldn't even waste your time going to the track w/o a chip burned for the gears. Put the money towards a chip. It'll be ok to drive around w/o a chip, but you won't get any "real" numbers till you get the chip.

BTW, I have yet to have any driveshaft issues, even with 2 very high speed runs (not racing, just by myself) when I had stock gear, and now w/ the 4.10's and been to 120mph (or close to) still nothing.
 

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If you unplug those sensors, the EEC will have no idea what the driveline speed is. How do you expect the trans to shift? How do you expect the converter to lock up?
 

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kdanner said:
If you unplug those sensors, the EEC will have no idea what the driveline speed is. How do you expect the trans to shift? How do you expect the converter to lock up?
Not to be a smartarse, but blown408 doesnt have to worry about that with an AOD car.
 

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3rd Gear Chirper
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Discussion Starter #13
Man, AOL sux. Glad I don't have it. I tried to log in yesterday to reply to this thread, and it kept taking me back to the log-on screen.

Anyway, looks like I'm ok as far as hitting the rev limiter (have J-Modded trans) but I'll need to bypass the driveline speed limiter to make a successful pass...someday I'll get a MMX driveshaft, but I guess just to make one pass I'll push my luck with the stocker. I'll just pull the plugs on the turbine speed and output shaft speed sensors, and the EEC won't be able to determine driveshaft speed.

kdanner- I can still shift manually...I always do anyway. The torque converter shouldn't lock up at WOT with the stock programming, and even if I did want it to, I have the ability to switch to manual control of the converter clutch.
 
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