Stop wheel hop 1989 FC

weezer · 03-14-2010, 12:53 AM

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

weezer · 03-19-2010, 09:26 PM

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

The best thing to avoid wheel hop is sticky tires.

Or drop in an N/A 13b.

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

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

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

03-14-2010, 12:53 AM	#1
weezer The Newbie Join Date: Mar 2010 Location: wichita, ks iTrader: (0) Posts: 5 Rep Power: 0	Stop wheel hop 1989 FC Is there an easy fix for wheel hop in 89 convertible when coming off the line?

03-19-2010, 09:26 PM	#2
weezer The Newbie Join Date: Mar 2010 Location: wichita, ks iTrader: (0) Posts: 5 Rep Power: 0	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??

03-19-2010, 11:44 PM	#3
josh18_2k Rotary Fanatic Join Date: Feb 2008 Location: Gresham, OR iTrader: (0) Posts: 473 Rep Power: 17	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 __________________

04-08-2010, 07:12 PM	#7
NoDOHC The quest for more torque Join Date: Sep 2008 Location: Sheboygan, Wisconsin iTrader: (1) Posts: 855 Rep Power: 17	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. __________________ 1986 GXL ('87 4-port NA - Haltech E8, LS2 Coils. Defined Autoworks Headers, Dual 2.5" Exhaust (Dual Superflow, dBX mufflers) 1991 Coupe (KYB AGX Shocks, Eibach lowering springs, RB exhaust, Stock and Automatic)

04-09-2010, 02:13 AM	#9
Whizbang Respecognize! Join Date: Jul 2008 Location: Δx = ħ/2Δp iTrader: (5) Posts: 3,190 Rep Power: 20	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? __________________ For current updates and event coverage check out Follow on Twitter! @WhizbangRally Whizbang Rally's Webpage \| Facebook

03-22-2010, 10:25 PM	#4
weezer The Newbie Join Date: Mar 2010 Location: wichita, ks iTrader: (0) Posts: 5 Rep Power: 0	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.

03-23-2010, 04:16 PM	#5
RXTASY idahorotary.com Join Date: Mar 2010 Location: Idaho iTrader: (0) Posts: 135 Rep Power: 15	The best thing to avoid wheel hop is sticky tires.

04-09-2010, 03:27 PM	#11
josh18_2k Rotary Fanatic Join Date: Feb 2008 Location: Gresham, OR iTrader: (0) Posts: 473 Rep Power: 17	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. __________________

04-09-2010, 07:22 PM	#12
Whizbang Respecognize! Join Date: Jul 2008 Location: Δx = ħ/2Δp iTrader: (5) Posts: 3,190 Rep Power: 20	+1 for FB? lol __________________ For current updates and event coverage check out Follow on Twitter! @WhizbangRally Whizbang Rally's Webpage \| Facebook

04-12-2010, 07:58 AM	#15
Whizbang Respecognize! Join Date: Jul 2008 Location: Δx = ħ/2Δp iTrader: (5) Posts: 3,190 Rep Power: 20	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 __________________ For current updates and event coverage check out Follow on Twitter! @WhizbangRally Whizbang Rally's Webpage \| Facebook