Interesting... so the throttle lag still exists even with a tune? At least it gets rid of the dead play in the throttle. I found that to counter the throttle lag, just pull in the clutch a tad longer than normal for the RPMs to drop before upshifting. I once did a few upshifts so smoothly that it didn't feel like I changed gears and I didn't slip the clutch either.

The drive by wire system sucks the big one.

 

GT

Well I have not tried any down shifts into 3rd at 100 yet (and I won't), but assuming stock gearing you are near the top of 3rd. And your engine will be just below red line (4500 in 4th to almost 6000 in 3rd). if you succeeded in getting it in (and what are you going to do, accelerate at red line?), you will have to really goose the throttle to get it to smoothly down shift at that kind of speed and you are better off to down shift at a slower speed (85-90) if your intention is to accelerate again. That’s pretty abusive and is not good driving technique IMHO.

The blocker ring is trying to get the input side to match the output side so the synchro slider can engage the spinning gear. The blocker ring actually acts like a clutch to do that, and when it’s worn out or abused it won't work effectively. Hopefully you have not put some kind of trick transmission oil that is too slick, as that will interfere with good synchro action.

 

I believe he was trying to get it into 3rd for engine braking, but I don't really understand why not just use the regular brakes. It's not like it's critical to get it into 3rd to slow the car down...you've still got regular brakes, and those should be your primary source of stopping power, especially if it's an emergency!

 

Don't downshift into 3rd gear near, at, or above 100 mph.

 

Well he did say he was going closer to 80 when he downshifted into 3rd. I think that's more reasonable. When you tach up the RPM's the Tremecs get unhappy.

CR
Tillman Speed

 

80 mph in 3rd is about 3600 RPM which should be do-able.

 

Yeah, that shouldn't have been too difficult to downshift. It wouldn't have wanted to go, but shouldn't have had to wrench on it, you know?

The Tremecs are really touchy. I have one in the Fox Body, and it's the same way. I know people running TKO's that still have had problems between disengaging and engaging depending on what part of the RPM scale they're at?

CR
Tillman Speed

 

Well for emergency deceleration the brakes are the way to go. If you are on the track and racing and that tight turn is ahead, then you want to go down thru the gears during that heavy deceleration before you enter the turn, taking advantage of the engine braking and hopefully be in a the right gear as you approach the exit of the turn so you have good exit acceleration.

At 100 MPH, a down shift from 4th to 3rd means the input shaft has to spin up from 4500 RPM to about 6000 RPM in a snap. Unless he gooses the throttle (a blip to 6000) when he declutches, most likely the engine RPMs are falling and working against the blocker ring (there is some clutch drag on the input shaft) trying to spin the input side up.

I agree these Tremecs are touchy and a disappointment to me as well (shifting up or down). Some blame could be related to the composite materials they are using on the blocker rings. Good old fashioned solid brass has always been reliable. I still say top loaders forever ...

 

I had a TKO in my last car and it was notchy at times, but I never had a problem match shifting to get into the curves on power. This thread lists two different problems. In street driving, the brakes work fine and no need to use the tranny and engine (IMO), but I can understand someone needing to get into a gear autocrossing, and it is not like we have a ton of torque at lower rpms.

Metroplex, yes it still exists and you are right on the timing. Sometimes I get lucky and you throw two more people in the car and you have to adjust yet again. I really think it is because there is no load on the engine and the computer doesn't really kick in until is has a load, even with a tune. With a load, you will really feel a difference with a tune. Even Bama's 87 performance is just really responsive. I found myself slipping the clutch too much with the '93 torque tune trying to get a smooth shift. Once the computer knew there was a load, the tune would kick in and start to shread the clutch.