Car is AT with 10,000 miles. Makes rattle / dieseling sound on acceleration up to 25 MPH. Sound comes from left front side of car very separate from engine sound. Dealer drove and heard it. We drove a used car on lot with similar mileage and heard as well. Dealer said its normal sound and may be air pump pumping air into exhaust sytem. Does not affect performance but sound is annoying. Ideas?

Same thing here. Quite a few people have posted about this issue and the dealer response has always been "normal".

When I put the REVi intake on, the sound was reduced, although never eliminated. The interesting thing was recently when we had a cold snap (40* F) the sound was again much more pronounced. :Wconfused

What is REVi intake? How much noise reduction does it yield? Cost and effects on performance and MPG? Thanks.

I'm so sure its the engine/tranny... maybe engine lugging cuz of lack of torque...

with revi don't you get a little tiny bit more torque... so maybe that would reduce the lugging grindy/tranny noise

Its the S-DAIS system.

When I put the REVi intake on, the sound was reduced, although never eliminated. The interesting thing was recently when we had a cold snap (40* F) the sound was again much more pronounced. :Wconfused


the colder it is the more the air pump operates as its purpose is to help get teh catalyst warm enough to do its job.

I'm so sure its the engine/tranny... maybe engine lugging cuz of lack of torque...

with revi don't you get a little tiny bit more torque... so maybe that would reduce the lugging grindy/tranny noise

?

There's plenty of torque to move a 3000lb car, particularly with the torque converter helping out.

I wonder if that's the funny little "high pitched warble" sound I hear when my accellerator pedal is pressed down to a particular point, regardless of speed or RPMs -- it's based on the amount of pedal pressure. Like, if my pedal were a knob and it were labeled from 0 to 11 (sorry -- couldn't resist (http://members.aol.com/chiprowe/gotoeleven.wav)!), then it happens around 3.4 -- not 3.3 and not 3.5, but "right there." :scratchhe

It's not especially annoying, just kind of "interesting" -- the only annoying part is not knowing exactly what it is and the teeny bit of concern that it might be a sign of trouble.

This is the coolest weather I've driven the RX-8 in so far.

If that's truly S-DAIS system, and thus is totally normal, then I'll stop wondering and be (again) thankful for this wonderful forum.

--Keith

What is the S-DAIS system and is this sound truly normal?

What is the S-DAIS system and is this sound truly normal?

http://www.rx8club.com/showthread.php?t=24649&highlight=s-dais

I had same question on noises at our dealers in SA and they say that at about 6000rpm a lot of stuff,like the powersteering,air con,and the air pump starts to cut back a bit and that also contributes to all noises that sounds different and then temp also has a change.dont know how true this is.
Did anyone take
(who are allowed to where you live according to laws) remove the air pump with belts and the cat etc. we had someone here who made a total new exhaust system and removed the cat,with no problems, and 18Kw gain,wow. they are now busy experimenting with new branches as well, this will mean removing the air pump as well.also a saving on one thing less for the motor to turn.they hope for 20Kw plus.Pipe is 76mm.
Will the management system have a problem with air pump removed?

it might light the CEL but it shouldnt effect drivability. it might take a little longer to warm up on cold days.

btw thats like 24 bhp for removing the cat. thats not likely unless the cat was partially clogged already.