SF@Rx7

i had a 84GSL-SE
just wondering can my car still handle downshift?

Project84

its not bad for the engine. Not bad for transmission either.

cach22

won't be a problem provided you match the revs by blipping the engine on the down change!

Lance

Project84

Not necessary if the syncros are working properly. But this will prevent wear on the syncro. But its not as easy as just tapping the throttle while you are between gears. You need to clutch in, shift to neutral, clutch out, rev to the RPMs that you will be at when you downshift, clutch in, shift down, clutch out.

The reason why is because when you have the clutch out and tranny in neutral, all the gears are still spinning at the speed that the engine was going before you pushed the clutch. When you rev the RPMs, they will all speed up. When you downshift, the gear you are shifting down to will cause the engine to rev faster at a given road speed. Lets say that at 50mph, 4th gear puts you at 2000rpms. If you down shift at 50mph to third, the bigger gear ratio (smaller gear=bigger ratio) will cause the engine to run at a higher RPM to maintain that speed. The Syncros allow the gears to go togther even though they are going at different speeds. If you do like I discribed and rev the engine while in neutral, those gears will speed up along with the engine, so when you shift everything is already at the same speed and you won't use the syncros.

Clear as mud?

Go to www.howstuffworks.com and you can look at how a tranny works and it will show videos of how all the gears constantly spin and how shifting selects each gear and how syncros work.

ShadowX

Is it necessary to put it in neutral? I haven't figured that one out yet.

Louis M

Good point, couldn't you just go: clutch down, shift, keep clutch down, rev, then release clutch?

Gene

iTrader: (1)

No, because if the clutch is down your throttle blip won't speed up the input shaft.

Project84

Roger that.

SF@Rx7

so what is the proper way to downshift?
1,clutch down
2,shift to netural
3,clutch out
4,REV
5,clutch down and shift
is that the right way?

Project84

A long time ago, that is what you had to do because there were no syncros inside of transmissions. Now you can just clutch down, shift down and go. The syncros do the work of matching the gear speed to the rear wheel speed and all that. If you know of anyone who autocross races, rally races, or anything where they race around a track and go into corners, talk to them about downshifting. They double clutch the way I mentioned above to save wear on the transmission and I think it helps accelerate better because you slow down some when you go into a turn.

3RotorRocket

Doesnt down shifting at a high RPM mess with anything?

Project84

If you are near red line, and downshift, then you will go way over red line and could possibly damage the engine. Tranny will be fine though.

Louis M

The money shift!

RidicilousRx7

i was taught to

clutch
downshift
rev
releaseclutch / rev

ERAUMAZDA

[QUOTE]Originally posted by Project84
[B]If you are near red line, and downshift, then you will go way over red line and could possibly damage

pop goes the wesel

specRX7_22

there are 2 things people are confusing here.... double clutching and just plain heel-toe'ing

double clutching, as project said, originated in older cars. Nowadays, thats not necessary (althought the original Fast and Furious made some kids believe it is).

heel-toe'ing is widely used today, mostly in auto-x and road racing. its purpose is to speed up the motor to match the rpms to what the motor will be turning AFTER the downshift, so you can rely completely on braking to prepare for a turn.

the trick with that is keep a constant and steady pressure on the brake while working the gas with the same foot. its easier with a set of pedals with that little extension on the gas pedal. its not necessary on the street, although it sounds cool with and aftermarket exhaust

specRX7_22

i have a story about a guy who downshifted at redline

https://www.rx7club.com/forum/showth...ht=racing+tale

3RotorRocket

Good one,he's lucky thats all that broke.

tancred

i like to drive next to people and they will downshift and just pop the clutch and their whole car jerks and bites down and the tires chirp....I often wonder if thats HEALTHY for the car?

JTurtonRX_7

just a wild guess..... but id say no....

JunpoweR

iTrader: (1)

Yes double CLutching is for older cars or ( DOG-Gears)
what are these DOG gears??
well they are bigger gears that are heavy duty and they are wider so it removes the syncros..why would you wanna do that??well some people do it to their cars because their stock gears are too weak so they just get biger beefer gears but to fit them in you have to remove the syncros.. but you can probably handle about 300 extra HP..but you dont really even need it for dog gears..
i can shift from 2nd to 3rd to 4th to 5th without even using the clutch pedal!!how do i do that!! haha wow its magic haha.. just kidding..clutchless shifting thats what i call it.. and some very experienced people will know what it is!!you just have to match the speed of the engine with the speed of the gears..i am not going to give a tutorial on it here.. just pm me if you wanna know how..but yes all of todays cars dont have to be double clutched just rev up while downshifting..but this is for mostly slow or sprited driving..but for race i say heel toe is best cause thats what i use..and yes
DOWNSHIFTING AT RED LINE IS BAD!!!
who the hell does that??
i mean rx7's do take high rpm abuse ok but it will damage ur seals and engine also it could lean out and burn everything!!