Downshifting over Redline?

[qsilver074]

There's a guy on the 3G Eclipse boards telling me that if you downshift at certain RPMs you will go over redline and blow the motor... is this true? He says his Eclipse won't do that.

[GTS LAID]

yes this is true... if you're travelling too quickly and you downshift into a certain gear and ignore the climbing revs as you let go of the clutch you will blow your motor... thats the problem with misshifting when people want to go from 5 to 4 at 100 mph and end up going into 2nd at 100mph... not a happy place to be..

and i dunno why his eclipse wouldnt let him downshift... the rev limiter wont stop you from revving your engine on a downshift.. only an upshift... at least thats how it is in the celica.. otherwise no one would be blowing their motors... and its not easy to control since when you're downshifting the wheels are driving all the shafts / gears / and when the clutch is engaged... also the motor.

[oldster]

Go back and tell him to stick his car into second at 80 and report back to you with the results. If he tells you he can't do it then he's just not trying hard enough. :)

[GTS LAID]

hehehe.. devious plan old man... the world would be a mesh of intertwined chaos if we all listened to you... lol

[EddieKP012]

I heard that some car won't let you downshift if your car will blow, like you can't drop to second at like 80 mph because of the ecu or something. They have it on all manual saturns. I don't know about the eclispe though.

[oldster]

And we're just supposed to believe some guy who lives out on an island somewhere..........don't think so buddy.........let's see the proof......:)

[scapamouche]

I have NEVER seen a true lockout for a manual that would protect you from overrevving.

As for the downshift thing, that's effectively what every person who has blown their Celica has done. They MAY have been trying to upshift (like me) but when they went from 3rd to 2nd, or whatever, that's a DOWNSHIFT!!! BOOM!!!

[GTS LAID]

yup thats what i did too.. 3-2(i think) instead of 4

[EddieKP012]

I posted something that I heard, I didn't say that it was concert fact or not, just something that my friend had told me. If you don't want to believe it fine, the hell if I care, then don't believe me. I was just putting in my two cents.

BTW, all the people in hawaii don't live in grass huts and go to the bathroom out in the ocean, we are just as advanced if not more then all you people on the mainland.

[oldster]

Gosh Eddie, I was just funning, didn't mean to upset you. :rolleyes: FYI, you are stating categorically that Saturns do have a lock out, are you sticking with that? :wtf:

[EddieKP012]

Oh sorry. I kinda get upset when people have the mentality that people in hawaii or on the islands are really savage and that we live in grass huts and such. so yea...sorry again.

about the lock out thing....I left out some rather important info that I didn't think was important at the time but I guess it is. My friend was trying to drift with the saturn and was trying to downshift into second from fourth to try and slow down but it didn't let him and now I know why.

In 1993, Saturn introduced traction control on its cars. The feature was standard on models equipped with an automatic transmission and anti-lock brakes. In later years, the system was available on cars with manual transmissions, too. There was no separate charge for traction control because Saturn engineers merely wrote additional software for the car's powertrain control module. The system uses ABS wheel sensors to trigger three levels of traction control.

1. When the ABS sensors detect wheel slippage, engine spark is retarted. This can cut the peak torque by up to 20%. However, retarding the spark can increase the combustion temperatures that can potentially damage the catalytic converter.
2. To prevent damage to the engine, the system upshifts the transmission. If the transmission is already in 4th gear, it will prevent the transmission from downshifting.
3. If car still does not have traction, the fuel supply is cutoff to the engine.

While this system doesn't work as well as those which use the brakes to limit wheelspin, Saturn's software-based system is still very effective and inexpensive.

I'm guessing this applies to manual cars as well since it states that it was added to manual cars later.

So I guess since his wheels didn't have traction, and the engine wouldn't let him downshift to second. Although I still don't see why this wouldn't work on a manual car, driving under normal traction circumstances, say like drag racing.


Oh btw, here's the site that i got the info from...
traction control (http://www.saturnfans.com/cars/features/tractioncontrol.html)

[MikeUK]

In the UK I've seen a few lock outs for 2nd gear that once the engine had gone over a certain rpm the gate locked out untill the rev's droped, messy, awkward, and could be a bit of a pain, and also not a 100% fail safe either.

[oldster]

Interesting, it doesn't sound like it would have any effect in the misshift scenarios we have seen from Celica owners does it? Seems like you could still pull second instead of fourth if you tried. Please understand when I say misshift I am talking about mechanically being able to go into a gear that will cause an overrev situation irregardless of the shifter pattern. I believe that scapamouche and I are in agreement on this.

[EddieKP012]

i guess so....I :bowdown: to you in defeat.....heh...for now... ;)

[oldster]

Originally posted by MikeUK
In the UK I've seen a few lock outs for 2nd gear that once the engine had gone over a certain rpm the gate locked out untill the rev's droped, messy, awkward, and could be a bit of a pain, and also not a 100% fail safe either.

I don't think that would help with most of the misshifts we have seen in the Celica. It would appear the vast majority have been done in a downshifting mode and going too far down in gearing. Sixth to second etc. instead of sixth to fourth. I'm betting in most cases the RPM are down prior to the misshift during the period of clutch disengagment. It would help in those rarer cases when someone was speedshifting up and missed the higher gear and got the lower. Hmmmm.........did any of that make sense?

[oldster]

Originally posted by EddieKP012
i guess so....I :bowdown: to you in defeat.....heh...for now... ;)

This isn't a battle, we are simply clarifying things...:chuckles:

[GTS LAID]

the thing is i dont see how it could prevent a mis shift unless one of two things happened.. either 1) it physically didnt let you into the gear... or 2) shut off the engine if you were insolent enough to go into the gear...

other than that as long as the wheels are connected to the diff connected to the gears and the engine there's gonna be a blown engine when you go into that lower gear.

[oldster]

hmmm.........don't think #2 would help either.......:)

[GTS LAID]

lol... ok just number one then... either way its very limited options...