Do You Rev The Engine Before Downshifting??

[DodgeViper01]

Hello everyone:

I just had a quick question, do you guys rev the engine before downshifting or do you just downshift with reving. I have the Reving before because it gets the RPM's close to where they are. The only thing that feel weird is that when I rev the engine before downshifting the car jerks forward a little bit. Is this normal? What do you guys think?

 

[PhoenixGTS]

I cannot get my car to downshift from 6th to 5th without rev-matching. Otherwise the idle hang usually serves as a freebie heal-and-toe to rev match for me. But generally, no, I don't bother.

 

[onerareviper]

F355,

Now all you have to do is brake at the same time (while blipping the throttle) and you'll be a heal/toe expert.

P.S. - If your car lunges forward (pushes you back in the seat), you are revving too high. If your car brakes(pushes you forward in the seat), you didn't rev high enough. If you match the revs perfectly (this should be your goal to keep the cars balance), the transition will be smooth as silk. When racing, you goal is to keep the car balanced and smooth (especially before a turn).

 

[V 10 MAFIA]

If you rev match exactly the car should not **** at all. Take note of exactly were the revs are at what speed in what gear.Ex: At 60 mph I know my revs at 3200 rpm match perfectly in third gear.

 

[Sean Roe]

Practice makes perfect when it comes to heeel /toe.
Let me know if you need any tips on it.
I've worked for 3 racing schools since 1988 and was taught by an instructor in 1987.
Regards,
Sean

 

[Vreracing]

I'm trying to get at least 50K miles out of my clutch. At 30K its still pretty strong.

For the life of me I can't heel toe on the Viper without turning my foot to almost 90 degrees.

With only 900 rpm on the tach I've found if I let the clutch out without at least a little blip on the throttle it grabs pretty hard.

I took a driving school. Derek Bell was riding along with me. I was half way through a turn and let the clutch out with the engine at idle. He just lost it. He started saying something about hitting a wall. (This was in a parking lot)

Ever since then, I've been frightened to let out a clutch without at least a little rpm on the tach.

 

[Steve-Indy]

Having been adept at heel/toe technique in various British cars, Porsches, Ferraris, etc...I was SURPRISED at how much I had to alter my technique in Gen I and II Vipers...now I just wear large soled athletic shoes, cover all the pedals I need (for the street).

 

[Chuck 98 RT/10]

Yes, I practice heel n toe on the street.

 

[Detlef]

Yes I do, it's good practice and in the words of one Skip Barber instructor, if ya got the pipes (meaning exhaust), the chicks dig it.

 

[ChicagoGTS]

Excuse me if I'm wrong, I'm not familiar with the heel/toe teq. But I thought that the purpose of reving was to to take the stress off the drivetrain and all of it's components and also conserving the time it takes to brake then shift. Engaging the clutch and then downshifting was the way I was taught, perhaps I'm wrong or missing something. Are you saying that you guys rev the motor while still in gear and downshift without engaging the clutch, that sounds dangerous.

 

[Cop Magnet]

I think there's some confusion in this thread. I am not sure F355 was talking about heel-an-toe at all, just maybe straight-line downshifting such as when going from cruise to "cruise-missile". In such a case, if you feel the car lurching forward "before you downshift" you are getting on the gas too early (before the clutch is in). Chicago GTS, the purpose of rev-matching is not so much for the sake of sparing the drivetrain as it is for not upsetting the balance of the car. The heel-and-toe technique is used when converting from brake to gas; rev-matching helps to make this transition with the least drastic change in the dynamics of the car. The more rapid the changes, the more likely you are to spin. Some people shift without clutching (I wouldn't), but that is not heel-and-toe.

 

[Steamroller]

If your car is jerking forward when you let the clutch back out after the downshift, then you are likely revving the engine too high... the engine's rotational inertia is attempting to increase the drivetrain's RPM as the clutch engages (thus, the forward ****). The car should not notably **** (in either direction) if the crankshaft RPM matches the transmission's input shaft RPM when the clutch is let out.

Regarding letting the clutch out after a downshift with the engine idling while entering a corner... When you let the clutch out, the rear wheels are having to rev the motor up. Due to the rotational inertia of the drivetrain/engine, the rear wheels are effectively acting like the brakes have been applied. Thus, you are essentially applying the parking brake... typically not a good thing when entering a corner.

 

[onerareviper]

Did someone say Day-ja-vu

 

[Shelby3]

I do it mostly to hear the exhaust blip. Never get tired of hearing that.

 

[Andrew2KRT10]

I have never had the need to rev before or while downshifting. In my opinion, if you have to match revs while downshifting, you are downshifting at the wrong time.

I'll keep this in mind when I'm downshifting after the tunnel turn at Pocono tomorrow.

AC

 

[Cop Magnet]

I have never had the need to rev before or while downshifting. In my opinion, if you have to match revs while downshifting, you are downshifting at the wrong time.

I'll keep this in mind when I'm downshifting after the tunnel turn at Pocono tomorrow.

AC

Again, maybe I am totally off--but I do not understand what you mean. If you are downshifting, there is a mismatch of revs. Doesn't matter at what point you are downshifting, the revs will go up. Hence, blipping the throttle--rev-matching. Can you explain to me what you mean by the right and wrong time of downshifting and how that would negate the benefits of rev-matching?

 

[Andrew2KRT10]

I find if I am traveling fast enough, and downshift at the correct time of decceleration, the rev is matched and the downshift is smooth. If I were to downshift to early, it's like I'm hitting the brakes. If I downshift to late, I loose power.

Like I said, I'll keep it in mind tomorrow.

AC

 

[Jeff Torrey]

Sometimes people downshift instead of braking (its called compression braking). Usually before a turn while racing, that way they are in the proper gear exiting the turn. But if you are to aggressive and don't match revs. the tires can lock up and you go sideways into the wall or off course. It happened to the guy in back of me on the track at VOI 7. Kind of freaky, all I hear is tires skreaching (could not see what was going on..the instructor had the rear view mirror). He kept saying KEEP GOING, KEEP GOING

 

[DodgeViper01]

Yeah I was inquiring about just regular downshifting. I guess I have to learn my car a bit more to see how to match revs. Right now I give it more that necessary and go over the amount. It is still better than giving to little in my opinion. Any others?

 

[Detlef]

Agreed, if you rev a little too much and realize it while the clutch is still engaged, just wait another few milliseconds and then release the clutch with it sounds closer to where it should be.

 

[DodgeViper01]

Sounds good

 

[VIPORXXX]

My2 cents on this: for street driving its really not necessary
to heel toe. I agree it sounds cool at times to do this and recently
I heel toe when driving on the street but only because I'm actually
practicing to be more proficient on the track.

Andrew-I heel/toe at Pocono especially in the tunnel turn when coming
from a high speed 120-130 down to about 20mph. I also do it on the short straight on the infield I do a 3 to 2 heel toe down shift.

Fast Eddie