RayC

During a "spirited" drive if i down shift hard and slow the car with the engine (while braking) i get a loud "growl" and some banging from the rear under floor

i have been told this is the diff snubbing but it sounds too nasty does anyone have any ideas
MY98 Type R 33,000 miles

Thanks

greasemonkey

You should be slowing the car with the brakes, not the transmission!

Difficult to work out exactly what's going on given what you've said so far. The "banging" is likely to be the diff bouncing against the bushes, but the "growling" sounds unusual, and unpleasant.

Is it also coming from the back of the car, is it there all the time (to some degree or other), is it directly relatable to road speed, does it stop when you've got your foot on the clutch, tell us more!

Either way though a slight modification of your driving style to place less reliance on engine braking would probably be a good idea. You don't get a lot of it in a turbo car anyway...

SiDHEaD

This happened to me when i was on track the other week - braking for a slow chicane! **** us up a bit, but nothing seemed to come of it...

Andy

RayC

it is only when commited, i do try to slow the car on the brakes, but if you down shift say 4th to 2nd hard (while braking) and it causes the engine to match the road speed, say takes the engine from idle (clutch in) to 5000Rpm then you get this deep growl and banging, it is a harsh manouvere and not during daily driving, but you can do it going into roaundabouts and tight bends etc

it is only when you load the transmission on downshift, on hard accel it sometimes makes a Woom Woom noise at approx 100, it does it in 4th and 5th, not always though, no noise comes from the diff or anywhere during cornering

thanks for replies so far

Leslie

That is a pretty poor driving technique. As well as being very rough on the clutch and transmission it is also bad for the engine to be accelerated like that with the throttle closed. There is no cushioning of the rods and pistons at high rpm from inertial forces with the lack of pressure in the manifold.

If you are really on the bitter edge as you approach a corner this technique could also cause you to lose control in a big way. The fastest and safest way through the corner is to arrive at the entry to the corner in the correct gear so that you can apply power smoothly as required with the car under some semblance of control.

Les

Gary C

I always down shift while braking, but I always toe&heel it.

greasemonkey

**** me. Agree with Les, this "technique" is mechanically umsympathetic, to say the least, especially if you're not heel and toeing. If you drive like this a lot, it's not surprising your car is complaining!

Competition drivers are told to leave downshifting as late as possible into the braking area, and go through the box in sequence, as this minimises the huge variations in off-power engine and transmission speed you are gleefully causing, reducing stress on both engine and gearbox in the process.

Suggest that a change in technique sooner rather than later might be good for the longer-term health of your car, and your wallet!