Megane Sport Forum banner

Revs take a long time to drop, why?

2042 Views 6 Replies 3 Participants Last post by  BlueyZarzov
It's something I've noticed a lot with new cars, but my last Renault was so old (1989 R5 GTE, <dreamy sigh>) it didn't suffer the problem. When you're in neutral and you rev the engine up for a moment it takes so very, very long for the revs to die down. It's the cause, I think, of my shifting problems: I can't get used to the revs not dropping fast enough for the gear change, and the revs are always mismatched for the new gear. I suppose I could shift slower, but I'd rather not coast down the freeway for two seconds waiting for the revs to fall.

What causes it? Is it something that can be adjusted/fixed?

I've gotten a couple of responses suggesting it may be illegal to stop it from doing this, and that in any case it would probably require changes made to the ECU.

Is this the case? The list of things that bug me about my beloved 225 is short, this is 50% of it. (other 50%: the windshield's hard to clean inside, grr).

Any information would be appreciated.
1 - 7 of 7 Posts
as far as I know the only thing that governs how quick your revs drop is the flywheel size/weight as this it what the inertia of the engine is pulling on when the engine is "braking" unless you have a light flywheel like in a rally car your always going to have the same issue

PS moved to tuning and technical :)
The problem is probabaly due to a bad and unevan (TPS) map in the standard engine management file of the ecu .

A remap can help for these little minor problems even on new cars.

Regards bell
Are you gentlemen saying that not all Meganes do this? I notice it happening on ALL modern cars, perhaps I'm not explaining myself properly?

Instead of VOOBAH, VOOBAH, it goes VOOBAAAaaaaaaa........ The attack is rapid, the decay is prolonged.

The first time I noticed it was on a new Honda Civic circa 1990. I really would prefer a little VOOBAH in my 225, you know? =D
I dont think its specific to the megane, all cars I've had have been the same, when you rev a motorbike engine up you see the difference the flywheel makes as the revs go from 14 to zero in like a second

should be an advantage on gearchanges though surely as your revs are higher when the clutch comes back up??
I couldnt comment as I never rev mine over 3000, honest. :wink:

If the attack is steep and the decay in revs shallow (and thanks for the musical analogy) then that is not likely to be flywheel weight related. I suspect that it is the result of the fuel/ignition map employed under a closed thottle, no load situation. The reason for this is increasingly tougher emission regulations that manufacturers must meet.
1 - 7 of 7 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.