I am having problems with snapping driveshafts and I really need some help as now I have broken 3 in the last 3 events.

My setup is:
JDM EF9 civic
Dry weight of 1800lbs
b18c with 215whp
Urethane engine mounts
S80 hydraulic gearbox with ATS 1.5 way LSD and 4.4 final drive
ATS sold centre metal clutch
ATS 1300kg pressure plate
ATS flywheel
235/60-14 M and H DOT tires

I have read alot about pre-loading the clutch which I was going to do in the last event but I broke my driveshaft doing my burnout. It was my first run of the night. I reved the car to about 8500 and droped the clutch in 2nd gear to do my burnout and it snapped straight away.


Sorry about the pic I took it in a hurry. It snapped off just after the outer CV joint. My last driveshaft broke in exactly the same place

I broke the centre driveshaft at the event before that



My questions are as follows:
1. Should I preload my clutch even when doing my burnout??
2. Is my clutch to harsh and should I change back to one with a sprung centre??
3. I am still running factory radius rod bushes could this be a problem??

Any help would be much appreciated.

 

check your mounts, make sure that they are not worn. also make sure that your engine, has very little front to back play!
check your axle's angle, if your car is too low to the ground chances are that your axles are at the wrong angle! the straighter they are, the less of a chance you have of braking them!
also with street/dot tires, keep tire hop to a minimum. install a traction bar, better struts/springs!
also wich axle do you keep braking, pass or driver side?

 

Its a right hand drive. The left hand driveshaft (passenger) keeps breaking.
I just checked the engine mounts and they are all good.
The driveshaft angle is almost straight.
Have had no problems with wheel hop they just snap as soon as I dump the clutch.

 

try a different clutch i had problems with that a few years ago on a solid disk clutch, try a sprung hub style , you don't need a crazy clutch for that kinda power

 

do they always break in during the burnout? are they dry burnouts? tires wet enough?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by flip1199 &raquo;</TD></TR><TR><TD CLASS="quote">do they always break in during the burnout? are they dry burnouts? tires wet enough?</TD></TR></TABLE>
Thats what I'm thinkin. Ive seen lots of people using stock axles and making more hp. Maybe ur being to aggresive, try pre-loading...
Also how about goin w/some aftermarket axles?

 

Only once on the burnout, yea it was a dry burnout as the track officials wouldn't put any water down, I usually don't have trouble doing dry burnouts. The other ones are off the launch. I don't think you can get aftermarket axles for a ef9, they have a different length drive shaft to everything else we have tried.

 

Hi civic5513: What air pressure do you have the tire @.

John
M&H

 

7 - 7.5psi

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by civic5513 &raquo;</TD></TR><TR><TD CLASS="quote">7 - 7.5psi</TD></TR></TABLE>

Bring your air pressure up to 10-psi and see if that will help and keep you from breaking axles. If it works, lower down the air pressure 1/2 pound @ a time to find that sweet spot.

John
M&H

 

From what you have posted. I would say that the car is too low. I had a problem a few years ago with braking axles and I raised the car up an inch and never broke another axle.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by civic5513 &raquo;</TD></TR><TR><TD CLASS="quote">My questions are as follows:
1. Should I preload my clutch even when doing my burnout??
3. I am still running factory radius rod bushes could this be a problem??</TD></TR></TABLE>

1. YES. there's no reason not to.

2. Have someone watch your front wheels when you launch (or even video tape it).. this might be pointless because I know you're going to see you wheels jolt violently forward even with a conservative launch. Just get some bushings or a "traction bar" setup.

 

IMO, You're being to aggressive w/ them. I've never had to rev to 8500+ and dump the clutch to get the tires to spin when cold(and I do 3rd gear burnouts).

1). You don't have to preload before your burnout because <U>NO Matter What</U> ,the track officials should have water down so that people are not breaking drivetrain parts trying to get heat into the tires. If they refuse to put it down than I would not return to that track.

2). ALWAYS preload your launches. Your car is entirely to light and low on power to be having these kind of problems.

Phil

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hondaguyef &raquo;</TD></TR><TR><TD CLASS="quote"> IMO, You're being to aggressive w/ them. I've never had to rev to 8500+ and dump the clutch to get the tires to spin when cold(and I do 3rd gear burnouts). Phil </TD></TR></TABLE>good point, when i used to run those tires i would dump the clutch at 5500 rpms and never had a problem. also, like john said go back to 10psi and work your way down! btw at 10psi, and dumping the clutch at 5500 rpms i would get low 1.8 60' times!

 

I have raised the car about an inch to run these tires as they are 25inches tall.
We have a photo of the launch and the tires are right forward in the guards and have been rubbing on the bumper some how when they are an inch clear when the car isn't moving

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by civic5513 &raquo;</TD></TR><TR><TD CLASS="quote">I have raised the car about an inch to run these tires as they are 25inches tall.
We have a photo of the launch and the tires are right forward in the guards and have been rubbing on the bumper some how when they are an inch clear when the car isn't moving</TD></TR></TABLE>

They probably rub when turning (Out of the staging lanes, onto return road etc.).I had that problm w/ 235/60's.

Phil

 

Preload...

 

sounds like slop in the drivetrain/suspension bushings if the wheels are walking forward on launch....does that sound possible?