Scrapiron7

Hey guys. Went to the local drag strip today and laid down some times to see what I could do. I was hoping for better times but I noticed a problem. First, here are the times

1. 13.5 1/4 mile with a .584 R/T
2. 13.6 1/4 mile with a .925 R/T

At the tree, on my first run I dumped around 4k and was getting absolutely god-awful wheel hop. I had to totally lay off the gas to get it under control. 2nd run I dumped around 3500, same problem.

Now, I have a stock R-1 suspension and was running on 245/45/16 Dunlop 8000s with only 5k miles on them.

How the hell do I elimate that wheel hop? Considering the mods I have and was running 12 PSI I KNOW I can pull off better times, but the wheel hop was totally killing me. What parts/mods do I need to make that no longer a factor?

Also, looking at my mods below and considering only 46k miles, what kind of times should I expect once the wheel hop is gone on 12psi? Thanks

M2 Intake
M2 SS Downpipe
M2 Heavy Duty Clutch
M2 Lightweight Aluminum Flywheel
Pettit AST
Brembo Cross Drilled & Slotted Rotors
Hawk Hp+ Pads
Goodridge Stainless Steel Brake Lines
Rotary Performance ECU
Rotary Performance Comp. Fuel Pump
A-Spec Tuning Midpipe
Apexi GT Exhaust
HKS EVC Boost Controller

Bryan

Van Sema

iTrader: (1)

do a search on wheel hop ... You'll find a ton of threads with the solutions.

good luck

Scrapiron7

Ok, so it looks like Trailing Arms or a launch kit would solve that problem.. Anyone have any good experiences with either the Pettit Street Kit or the M2 Trailing Arms?

the_saint

The trailing arms and unobtanium diff bushings got rid of the wheel hop I had. It was so bad that I thought the car would blow up, but now the wheels spin for a moment and then it hooks up and goes. I have had a few moments of wheel hop but i don't even notice it anymore.

I have the Pettit Street kit, very easy to install and works great in my books.

thesaint

R Xplicit

i have been considering installing one of these kits, most likely the pettit one, but am a bit worried about the handling of the car afterwards. i have read in a few posts that the toe-links and the trailing arms make the car feel slightly 'out-of-control or unstable at high speeds....is this true for some of you launch kit owners? i would like to hear about them if anyone feels like sharing.

Section8

iTrader: (6)

I was reading about the pettit kit last night, and I was wondering how it would affect the handling of the car on a road course, or if it would even be necessary. I'm not planning on doing any drag strip stuff when I do get an FD...

the_saint

The trailing arms control fore and aft movement of the axle, which your wheels should not be doing.

The toe links control wheels from turning in or out (the rear ones).

I have not noticed any problems with high speed handling, if anything my outer toe link bushings were shot (banging going over bumps from the rear, right worse than the left, and while shifting) and the handling was a bit unpredictable, esp during autocross. Replacing them made a world of difference, and the car handles much much better.

thesaint

Pressurized

Don't hesitate to heat those tires up, that's what the water box is there for. Just spinning them for a second doesn't do too much. Get in there and skirt those bad boys, you should get a lot better grip and not hop.

LUV94RX7

iTrader: (3)

LaBreck's bushings might help.

Ken

rx7tt95

I have the M2 trailing/toe links combined with Tein HA's (not exactly the best pure drag setup). What I noticed was that wheel hop was greatly reduced, not eliminated. The car is lowered quite a bit and I did put the fronts on full soft. Wheel hop is worse if running larger diameter rims on street tires, less so using drag radials. I use BFG drag radials on stock rims. The trick is to get a bit of "smooth" wheel spin which translates into grip as the revs get higher. Bogging will sometimes exasperate the problem as you really need to stay in the power at the launch to the point of loss of traction (duh). I did run a fairly firm setting in the rear to help the osciliation of the suspension as well. You might try running with a bit more gas than usual, say 1/2 tank or more. To sum it up, any of the trailing/toe kits will not eliminate wheel hop but they will help.

I've run with and without them and managed about the same times on 17" rims and the touring suspension as with the 18" rims (same brand tire) and modified suspension. I've duplicated my times on drag radials as well. The car however, due to a few small problems, was not running as well as before, so with a proper launch, I could probably knock .2 off my 1/8 mile times. I've run as quickly as an 8.0/90+mph with the 18's, and generally get consistent 7.8-7.9's at 93mph with the drag radials. 60ft. times are around 1.8-1.9, never better sigh....As a reference, a 385hp Z06 on 18's was running 8.5's and higher with an identical 60ft. time.

yy4u

what all is included in the pettit steet kit? how long did it take to install? Thanks!
-Rob

the_saint

Trailing arms took about 30 minutes to install, very easy

I did them with the diff bushings. Everything took a couple hours.

thesaint

turbojeff

iTrader: (30)

Try lowering rear tire pressure to 20-25 psi. Don't "dump" the clutch but slip it a very slight amount on launch, this is also easier on the drivetrain (except clutch).

RT isn't really important although the .5xx time was nice. What were your '60 times?

Jeff

rx7tt95

If it's an organic disk (Mazda OEM or equivalent) and you slip it, it will burn up rather quickly, in as many as just a few passes, fyi. Ask me how I know :-) I've been through the stock clutch, ACT HD, and I have an ACT Extrme now, all using the OEM disk. I know it's a bit off topic, but if I had to do it all over, I'd go with the Extreme pressure plate and one of the sprung hub disks from Clutchmasters.
Michel

yy4u

So the pettit kit is what exactly? does it include differential bushings by any chance? Is its trailing arms and toe links, or either or neither? Sorry i should probably just call pettit or something, but any info is appreciated.

Also, do trailing arms and or toe links introduce vibration from the drivetrain. Which bushings do these take the place of? I was goign to get the entire set of 18 bushings but now i'm thinking about only getting the differential bushings. Please someone offer up some insight. My car clanks like crazy and wheel hops with the best of them

-Rob

rx7tt95

I was expecting lots more noise by using M2's solid bushing trailing/toe links (which I suspect, are very similar to what Pettit has to offer). Surprisingly, I didn't notice any increase in noise. I am using stock bushings everywhere else however.
Michel

rotary-tt

I am getting the same ET as you although I still use the stock ECU. Bad wheel hop, only if I launch at high rpm. The car launches better with a lower rpm launch. I don't remember my reaction time, but my problem is my 2.2 60'. I was running Dunlop 4000's at about 22psi. If I could get rid of the hop and had some drag radials, looks like 13flat or 12.9 ET.

You don't want to back up in the water with treaded tires. You will just get water in the tread and spin more. The water is for heating up slicks. I've seen several articles about heating up street radials. You usually just make them greasy and spin more.

I don't think the links will solve all of your problems unless the rest of your suspension is in good shape. The hopping will blow out your RR strut, and you may have bad differential bushings or a cracked PPF.

And yes I would stay away from slipping the clutch unless you like replacing it often. Better to slip the tires...

GoodfellaFD3S

iTrader: (213)

Be careful with wheel hop--I cracked my ppf in 3 places at the strip due to wheel hop, and the problem got worse enough over the next few weeks that I couldn't drive the car. I could actually hear the metal creaking and bending as I backed out of my garage. Luckily, Dan Schecter at RP helped me out with a used ppf

Btw, I was running 245/45 SO2pp's (not exactly drag tires) on stock rims and launching at 3-3.5k rpms.

Bucrx7

[QUOTE]Originally posted by rotary-tt
I am getting the same ET as you although I still use the stock ECU. Bad wheel hop, only if I launch at high rpm. The car launches better with a lower rpm launch.

My car is the opposite, when I launch aronud 2.5-3k I get wheel hop, yes it's wheel hop not bogging. When I launch at at 4k+ I have NO wheel hop at all. I run stock rims with stock tire size 225/16 and stock R1 suspension. I was told that with the stock rims and tire size you're not suppose to get wheel hop, it also depends on how much tread you have on your tires. I guess each car is different.

the_saint

The pettit trailing arms (street launch kit) are just that the trailing arms.

Their drag launch kit include the trailing arms, diff bushings as well as lower link bushings.

When I installed my trailing arms (street launch kit) I also installed a set of unobtanium rear diff bushings. There is a noticeable increase in noise and vibration from the rear. There is also gear noise which i don't mind and my friends think sounds pretty neat. The rear end is much tighter.

I launch around 3.5k and higher, anything lower I can still get wheel hop, but much much less. Where as before I installed everything I would always get wheel hop, unless I really killed it above 5k, but then I would never hook up.

I think with higher mileage, you will get more wheel hop. As the bushings wear there is more give in the suspension, and wheel hope will be more pronounced.

thesaint

ajmacdon

High speed handling is greatly improved with the Toe links and trailing arms. They were originally designed to eliminate the passive toe steer from the factory allowing you to set the toe where you want it instead of trying to guess where it will go in a corner.

I run 1/16" toe in at the rear and have never experienced a car this stable and comfortable on the track. Before the toe links and trailing arms I could never tell if the car was oversteering or if it was just "toe steering" due to bushing flex.

IMHO the side benefit of the M2 and Pettit "toe control kits" are that they might help you straight liners launch better

justin

I ran two times before getting a pettit launch kit.Horrible hop and 60'times.
The launch kit is a must if you plan to play at the strip
Pettits original kit started out as a road race piece for their own track car, the by product
being it cured about 90% of wheel hop for all the people who started to drag race their 7s.
I bought the race kit as it was all that was availible at the time.
Also drag radials @ about 16psi seem to help.Takes a little practice but if you get your 60'time
below 2.0 you should see 12s at least

rx7tt95

Update!

Some may know my car has been in and out of the shop, mostly for re-alignment of body work and fixing problems with the paint. While it was being fixed from my accident, I installed a completely new suspension including the M2 trailing/toe links and Tein HA adj. shocks amongst other things. I had been hearing rather lound clunks coming from what seemed was the driver's rear shock tower. The body shop, who installed the suspension as well, insisted that it was the muffler piping hitting the diff (which it was due to a slightly bent PPF which they didn't catch). It really sounded like they had left a tool in the roof somewhere.

Turns out it was because they installed the stock shock mounts incorrectly, despite the fact I loaned them my shop manual. So instead of working as they should, the top of the shocks were literally banging up against the shock tower. Not good.

It's relevant because my observations of the M2 stuff not completely eliminating wheel hop are completely invalid at this juncture. The three times I've been out to the drag strip since having the car returned were with the bad installation. I may try and hit the track tomorrow night to see if the wheel hop is in fact eliminated because of the M2 parts. I'm amazed that I was able to duplicate my previous times with BOTH rear shock mounts installed incorrectly. Strangely enough, the fronts are fine. Have to love hired help!
Michel

GoodfellaFD3S

iTrader: (213)

Sorry to hear about that...at least there are no lingering problems from the incorrect install.

You know what they say--if you want something done right....

lane_change

iTrader: (20)

...pay for a good shop to do it.