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-   -   Stop wheel hop 1989 FC (https://rotarycarclub.com/showthread.php?t=10704)

weezer 03-14-2010 12:53 AM

Stop wheel hop 1989 FC
 
Is there an easy fix for wheel hop in 89 convertible when coming off the line?

weezer 03-19-2010 09:26 PM

Talk to me.
 
After owning 2 corvettes, I love my VX7 vert. Drove it out of curiosity and fell in love with the ride, handling and overall build quality. But the wheel hop is a disappointment. Struts and bushings are in good shape. has anyone else had this problem? Suggestions??

josh18_2k 03-19-2010 11:44 PM

i have all all quality crap in my suspension, and it still hops sometimes. not nearly as bad as with original bushings, but its not completely gone either.
there are a bunch of things you can do to reduce it, but it'll probably never go away:
solid rear diff mounts with collars (custom part- basically filling the gap between the crown and the diff on the rear mounts with a hockey puck or aluminum or whatever), subframe mounts, stiffer shocks, make sure theres no excess play in the diff

weezer 03-22-2010 10:25 PM

Thanks Josh. the differential mounts are the only thing I haven't checked. will do that ASAP. The design of the rear suspension isn't the brightest idea from mazda. It pulls the body down on acceleration, instead of pushing up to get more traction. On regular leaf springs I have used traction bars, but the way the RX7 is built, it doesn't look to be easily done.

RXTASY 03-23-2010 04:16 PM

The best thing to avoid wheel hop is sticky tires.

My5ABaby 03-23-2010 05:13 PM

Quote:

Originally Posted by RXTASY (Post 113417)
The best thing to avoid wheel hop is sticky tires.

Or drop in an N/A 13b. :rofl:

NoDOHC 04-08-2010 07:12 PM

Actually, I have found that adjusting the rear shocks stiffer will actually improve wheel hop (I had serious issues with it before). Setting KYB AGX shocks at 8 seems to fix the issue almost entirely.

This is actually the opposite of the setting required for maximum weight transfer and minimum axle hop on a solid rear axle car.

I think that weight transfer is not as good with the stiff shocks, but the car still launches at >1g with factory size tires on it.

RETed 04-08-2010 10:52 PM

Quote:

Originally Posted by weezer (Post 113329)
Thanks Josh. the differential mounts are the only thing I haven't checked. will do that ASAP. The design of the rear suspension isn't the brightest idea from mazda. It pulls the body down on acceleration, instead of pushing up to get more traction. On regular leaf springs I have used traction bars, but the way the RX7 is built, it doesn't look to be easily done.

Wow, calling a bunch of engineers "stupid" isn't exactly bright either...

The car wasn't made for drag racing.
Thinking it is isn't too smart on your part.

What I'd like to know is why the F*CK are you trying to drag a convertible, which has the crappiest set-up to do this in the first place?
(i.e. 3.90:1 stock rear end?)


-Ted

Whizbang 04-09-2010 02:13 AM

it might just be me (or physics) but isnt the downward motion of the body relative to MORE traction due to the weight transfer vectoring forces down onto the wheels?

RETed 04-09-2010 05:40 AM

Yes, if we're strictly talking about dynamic loading forces of the chassis while ignoring the dynamics of the rear suspension.
The reality is with the K-M hub design of the trailing link rear + the DTSS crap, you get additional changes in toe and camber, while is detrimental to getting as much traction in the rear on a hard drag launch.


-Ted

josh18_2k 04-09-2010 03:27 PM

lots of squat = good
camber gain with squat = bad

so it kinda evens out to being pointless. every suspension design is "stupid" compared to wishbones, but we get what we get.

Whizbang 04-09-2010 07:22 PM

+1 for FB? lol

Lastphaseofthis 04-12-2010 01:04 AM

Quote:

Originally Posted by RETed (Post 115123)
Wow, calling a bunch of engineers "stupid" isn't exactly bright either...

The car wasn't made for drag racing.
Thinking it is isn't too smart on your part.

What I'd like to know is why the F*CK are you trying to drag a convertible, which has the crappiest set-up to do this in the first place?
(i.e. 3.90:1 stock rear end?)


-Ted

I tough all verts had a 4.1 because of the weight? even those with auto trannys, although the auto coupe's have a 3.909, or do i have it backward?
Sorry i'm to lazy to jack up the vert make some marks and spin the wheels...

RETed 04-12-2010 05:07 AM

All US-spec convertibles should have the 3.9 rear end.
The 3.9 compensates for the auto trans and increased weight to comply with CAFE mileage rules for Mazda.


-Ted

Whizbang 04-12-2010 07:58 AM

and they were all open diff too. I could have sworn i came across information about the convertible diffs for S5 models being 4.10s tho


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