BHANSON

After extensive testing, I have found that the rev. matching feature causes tip-in hesitation when up shifting from 1st to 2nd and upshifting from other gears. It is more apparent in the lower gears and has presented complaints by many owners of the Z06 manuals.
If anyone has any questions, you can contact me on the forum.

Bill Dearborn

In two plus years and 10K miles of driving the car I haven't noticed any tip in hesitation when shifting. The car sees a couple thousand track miles each year and I really haven't noticed any hesitation when up shifting as I power off a corner at wide open throttle and then shifting from 2nd to 3rd, 3rd to 4th or 4th to 5th. I get that sequence once every 2 plus minutes at VIR when I drive off Oak Tree and up the back straight (say 8 or 9 times per session).

Bill

breakskeet

Good conclusion. You would be a good candidate to try Tony Mamo’s ported throttle body and see if it really does reduces or eliminates tip-in hesitation. Many have claimed it does.

BHANSON

Mamo's had no affect. Just don't use rev match if on the street and have the hesitation.

BHANSON

I didn't notice the hesitation problem on the track only on the street at moderate to medium throttle. I have 20K miles 2016 and it has been annoying for at least 10K miles. Now I do not use rev match on the street and only on the track because it was very annoying. Because of the many postings about this tip-in issue, I thought I would alert everyone of their possible cause if manual trans..

salcolkat

What is tip in hesitation?

BHANSON

Tip-in is when one depresses the throttle starting at 0% and then depresses the throttle 10 to 30% and the engine stumbles or hesitates for about one second before normal acceleration. If you are familiar with carbureted engines, it is if the accelerator pump is defective or maladjusted.

Z0HS1CK

At first i never used rev matching. Then about 3 months after owning the Z, i make sure i turn on rev match whenever i start the car. Now it becomes second nature. Similar to people who turn off TC as soon as they start the car.

I never experienced what you said.

I know you said TM's PTB had no affect but maybe other TB's might?

I have a katech PTB and it made night and day difference with throttle response. It still has a SLIGHT lag but i think this was done in purpose by katech for better driveability. So it won't be super sensitive as opposed to super laggy from a stock TB.

breakskeet

So you have a Mamo on you car?

I have an A8 and while tip-in is not as pronounced in the automatic, I can tell a difference with the Mamo installed.

3 Z06ZR1

On my M7 the rev match has nothing to do with the upshift. Only blips the throttle on downshifts and it has to sensed from the transmission.

The MAMO PTB fixed the huge bulk of the tip hesitation problem. I never have the rev match switched on.

My A8 had no issue it just goes off smoothly.

salcolkat

MMMM? I have 5000 miles on my 2017 m7 and never noticed it. I do have the Callaway 757 package. Don't know if that would affect gear shifts?

BHANSON

I use HP Tuners to evaluate what has been occurring. I do not think Automatics have this particular problem It originates in manual car's software and during upshifting not downshifting when rev match is activated.(rev match does blip at upshifts if needed) Mamo's TB may affect and improve other issues but not this one. I tried it. I can imagine it may improve throttle response but so will the Vitesse throttle controller(works great for changing throttle response). What I have found, increasing the Transient function in HP Tuners has a major affect on throttle sensitivity by increasing short term fuel delivery when moving the accelerator pedal.
So, automatics please ignore my post. If rev match is activated, you have a manual trans, are applying moderate throttle you may experience this hesitation which I found very annoying. On the track, rev match works fine because the throttle is usually to the floor.

ronsc1985

I think the OP has not thought much about how rev match works.

On a down shift the control system applies throttle to increase the crankshaft speed to the transmission input shaft speed dictated by the current rear wheel rpm and gear selection. This can be a rapid correction because you are applying a power increase to an essentially free wheeling engine.

On an upshift there is no such easy rpm change method available. You are depending on engine drag to slow rpm's. As such, depending on the spread between gear ratios, it takes more time to achieve the required synchronization. The ratio spreads constantly decrease as you go from 1st on up. While the ratio spread doesn't change vs rpm, the engine drag does. Due to this the delay from gear to gear is not constant but depends on the current rpm and the gears in the shift sequence..

The long and short of it is simply doing an upshift match takes longer then a downshift match between the same two gears and this delay increases as sum of the gear numbers selected is lower. i.e. 1-2 takes longer then 3-4 etc.

If this bothers anyone I'd suggest you delay getting back on the throttle on upshifts particularly when using part throttle. It's just the nature of upshift rpm match.

BHANSON

I have Callaway also and is when I began to notice this. I have been working with Callaway on the issue so that if other customers experience the problem, they should bring the rev match issue to their attention as a possible explanation.

BHANSON

Great explanation and upshifting slowly helps. Best is to not use the rev match because I found it so annoying except at the track.

3 Z06ZR1

The issue I "had" I use past tense because the MAMO PTB fixed 95 percent of it to the point where it is not an issue. Nothing to do with rev match as this was happening only starting out in 1 st gear no other gears or shifts are effected.

Plus do a search an find many others had the same issue and found relief with the MAMO PTB. Not the issue at all
your talking about. Up shifts are smooth and normal with or with our rev match on with my car and the rev match works perfect on downshifts only!

3 Z06ZR1

After rereading your post. we have different issues yours sounds like it needs a trip to the dealer. Not typical of the normal M7 but the tip in hesitation off idle response starting out in 1st gear only is.
It is lessened by the PTB as evidenced by other s in this thread and hundreds more if you do a search!

Z0HS1CK

That's what i was thinking when i read the original post.

He has another problem.

spearfish25

I generally don't use rev match unless on track due to a few issues. I don't know if I can nail it down to tip in, but the rev match on the Corvette is not up to par with Nissan's 370Z version or Porsche's rev matching on the manual 2018 GT3.

The Corvette rev match on street driving downshifts leads to rough engagement. It has a feeling like it's not matching revs spot on or trying to hold them after clutch engagement when the car would naturally be decelerating and revs should continue falling. If I turn off rev match and do it myself manually, the downshifts are smooth.

On upshifts with rev match while street driving (non-redline shifts), there is a similar clutch-throttle relationship issue that leads to rough upshifts. It's subtle but a 'type A' driver notices the difference. I can even hear the difference in the exhaust sound during the shift where it makes a strange vacuum or poof sound during the upshift. Turn off rev match and the upshifts are smooth again.

I finally just decided the Chevy didn't get rev match quite polished in my 2016 Z06. Perhaps later years have improved. The other automakers have done a better job.

6Speeder

To the OP: Something other than rev-match is causing your problem. My 2015 Z with M7 has no hesitation, rev-match on or off.

to 3 z06zr1: Rev-match works on upshifts also. Try clutch in, let your revs drop to idle, then shift up. Rev-match will raise the revs to match the higher gear.