amartin

Hi.. I just bought an RX-8 ... I took a demo model out for a test drive (which had enough miles where it was okay to really get on it).

I also have an S2K, and so, I'm fairly used to high rpm clutch drops, and a 9k redline, etc...

I launch the demo model a few times, (traction control off), and the rear wheel hop was HORRIBLE.

Without screwing with tire pressures too much (as droppig the PSI, if that works, changing the bias from rear/front like that is going to make cornering in an auto-cross bad).. What mods (I assume suspention) can be done to reduce wheel hop on a had launch?

Thanks,
Aaron

Omicron

This would be a good question for Judge Ito, who has produced the best times from a stock RX-8 thus far... 14.3 or so. He can usually be found in the "Racing" forum. Check out this thread too: https://www.rx8club.com/showthread.p...threadid=15997

eccles

Stiffer shocks would reduce the axle tramp.

syntrix

Axle tramp is different than reducing wheel hop. You are correct that axle tramp can be reduced with increased dampning in the shocks on the drive axle side.

Usually it's caused by all the engine/tranny/diff mounts being made of soft rubber.

The first thing to do would be to swap all the mounts out to a poly, but I know of nothing avail at this time.

That's usually the first thing that you do to reduce wheel hop, but in some cases you may not be able to eliminate it 100% unless you do special modifications.

I agree, this car does wheel hop a LOT, and even with my JIC coilovers on a hard setting, the car will still hop. So it's a function of the mounts as the starting point right now.

Hymee

iTrader: (1)

So what is "Hop"? I have not had axle tramp in mine. Just nice spinning wheels, with a bit of slight drift as it comes out of the blocks.

Cheers,
Hymee.

eccles

On normal pavement, I experienced the same as you, but on the drag strip, where the coefficient of friction is so much higher due to all the rubber and gunge on the pavement, I got really nasty rear wheel hop with high-RPM clutch dumps.

hasg

I went to the drag strip and tried launching from all different rpm's (8k, 6k, 5k, and 4k). Each time the wheel hop was horrible. I'm going to fill the motor mounts with poly and lower the tire pressure a little next time.

RX-jimenez

nothing in the hop issue??? what will stop this!!!! is getting annoying to me...."_

Lawerence

Can you read?

FILL THE MOUNTS WITH POLY URETHANE.

Just make sure you allow them to dry for 1-2 days B4 using the car again.

paradigm

RX7's have huge issues with wheel hop too. There are a few things you can do to solve them on the 7. Building a simple differential brace on an 7 helps considerably with wheel hop. My friend just bought the materials to make one for his 7, and I told him to buy some extra for me. I'll be trying to build one for the 8 in the next week, so keep an eye out and I'll let everyone know how it goes.

RX-jimenez

fillyng the mounts with poly urethane is not good, my friend tested and guess what he had to order new mounts to change the ones he filled, it gives you a real bad vibration in the stering wheel like you are driving a 1950 Ford....

syntrix

Ok, something isn't right on that post! Vibration that bad should not be happening.

However, if you stiffen the mounts, you WILL get more vibration in the car, and the steering wheel.

My guess is that your "friend" has an older car, and not an RX8? Modern day cars have engines that are more balanced, so the harder mounts don't show as much vibration.

Lawerence

Syntrix is exactly right.
My friend has them in his RSX-S and while his car does vibrate a little at idle, but once you move its all gone.

And with the smoothness & balance of a rotary it shouldnt even be that bad at idle.

amartin

"And with the smoothness & balance of a rotary it shouldnt even be that bad at idle."

...well, I don't know what car your driving, but my rx-8, and the RX-8's I've driven or ridden in are ANYTHING but smooth at idle. They vibrate like a freakin harley.

Go sit in a $9k Geo Storm..it'll idle smoother than an RX-8.

Unless your kidding of course...because this car isn't smooth..at all. I still like it, but your statement is false.

Lawerence

???
Are you crazy? This car is insanely smooth!
Maybe you should have yours checked out...

amartin

Check out all the posts about people who have vibration issues at idle..

(Note-- its not present when engaged in gear and moving, just idle).

..Kinda like the bad-gas milage issues... some have 'em, some don't

R8N8SIS

i think the 8 is as quiet and as smooth as my is300..

hondas2k

It is not that the engine is not smooth when driven, but there is a noticeable vibration felt through the shift **** at idle. It is not noisy nor does it feel like the manual tranny in some older trucks that I have driven that vibrate like crazy, but as smooth at the engine and **** are while driving, it is odd that it vibrates so much at idle.

This vibration does not bother me at all but I just wanted to try to "smooth" this thread out so there are no misinterpretations.

Kirk