At the last autocross we had a large sweeper starting in second and finishing in third. I could not hit third while turning, another driver said that during the turn there is stress on the transmission and it is tuff to shift. Is this true, the car runs perfectly other than this incident.

Thanks

 

Using stiffer engine and tranny mounts would help this alot...

 

Thanks for the input, it may be my driving no one else seems to have the problem.

 

You should be able to shift and turn at same time, i would not think there was enough stress on the tranny internals to keep you from shifting any more so than launching the car....

 

What was the issue...shift lock out, grinding, or...?

 

I dunno why you'd have to be shifting in a corner. I can't remember ever having to do this. I heel-toe downshift while approaching the corner in the straightest line possible and then trail off the brakes as I turn in if needed. It's best to downshift as late as possible, right before the turn in. In a corner, just ride out the gear you're in.

 

Can't argue with that advice. You should never be shifting during a corner.

 

I was up shifting comeing to the finish line. I hit the rev limiter in second. Through the finish 75-80mph.

We have another event 10/8. It is with Corvette club, we get 14 runs for the day. I am going to be aware of the cars position before the upshift. Northeasat Florida area.

 

I had this issue at the last autocross i ran. It was an autocross on a roadcourse, and it was a long corner in which we entered in 2nd gear, and then shifted UP into third. while in the corner.

It's not fair to say "dont ever shift in a corner" because upshifts come where they do pretty much, downshifts sure.. do them on entry while braking in a straight line.

I hadn't had issues with doing this in the AMS car, or the other Evos I have driven, but recently I have had issues. There seems to be some discrepiency as to different cars and level of difficulty doing this. Now that I have driven probably 15-16 Evos hard and at Speed, some of them seem to be harder to shift because the clutch has to be ALL the way in. Combine that tendency with a corner and flex, and you get a very tough shift.

The answer.. yea engine mounts and such will help, but if you are not going that rout, take the time to do the shift right, clutch to the floor, easy handed gear change, and then let the clutch out. Will it be slower than what feels right? Sure, but better than trying to ham fist it and missing the shift or screwing up the corner.

To add to this.. sometimes you even have to downshift while cornering.. you might have a complex of corners that you have to slow down in, or a spot where you are transitioning from one corner to another when you need to brake and downshift. The answer is be smooth, and as with braking while cornering, be gentle, and feed things in slowly, with the shift make sure to keep the revs up through heel-toe so as not to lock the wheels.

Jon K
www.racerjon.com
www.seat-time.com

 

Jon


That makes sense, I was pushing hard and probably rushed the shift. Thanks for the clear explanation.

Tom

 

Jon

We had an autocross event Sat. Again while turning (.5 gs on the G-tech) the car will not go into 3rd from second. If I straighten it shifts fine. My friend runs a Miata (with 240whp ), and he has the same problem. This is not a normal autox, it is sponsored by the Northeast Fl corvette club. Our exit speeds are at 75-80. Our rev limiters are at about 8200 rpm, I know because I gave up on 3rd on one run and let it bounce off the limiter through the exit. My car shifts perfectly in every day driving.
Thanks for the prevoius post. Will the stiffer engine mounts help, this seems to be a problem between the wheels and transmission.

Tom

 

That seems weird, I will get to drive a couple more Evos on Friday, and I can ask those owners as well, but its a trend thats puzzling me..


Do this though.. Check for excessive engine movement, power brake (like heel-toe) and come off the clutch while someone watches the engine move.. see how far it has moved, it might be that there is a bad engine mount..

have you had any work done to the car.. clutch or something like that which could mean some mechanic didn't tighten one of the moutns down?

I think new mounts would help yes, but i cant see why its this much problem in the first place.

Jon

 

Jon

The car has 6000 miles and no work has been done.

I will check the engine for movement this weekend.



Thanks for the interest.



Tom

 

I have the same problem during the 1-2 shift while drifting a turn.

 

in general, if you're upshifting mid-corner, you're taking an inferior racing line through the corner or you're just not keeping the car at its limits...you're losing time either way. the only scenario i can imagine where upshifting mid-corner MIGHT help is a really long increasing radius turn? but even there, an earlier apex might allow you to enter the turn in the higher gear and carry more speed? i dunno?

can you describe the corner where this happens?