Last night at the drags was less then successful.. on only my second run for the night, the car felt a bit harsher then normal pulling through the revs. On the return road, I could hear this god almight rattling from the engine bay (it's very noticable - people in the stands could here it too.)

Parked the car up and having a look, it seems to be coming from the back of the motor. It's there from the moment the engine is turning over and doesn't seem to matter whether it's in gear or not. I did try revving it to 1500rpm or so and it does seem to alter the rattle - seems to be a bit better to be honest. At first I thought it was a broken turbo but the noise is from further back in the engine bay. The general consensus is that it could be either a rear flex plate or internal damage. I decided against driving it home and stuck it on a tow truck.

The car in question is a 2003 XR6T auto with 70k's on the clock. Internally its got Typhoon valve springs but the rest and the bottom end are all standard. It's running 13psi of boost with an edit from xtreme and has fuel injectors and a bigger exhaust etc to cope with that. I was changing at 5700 - 5900rpm during the run, exactly like I usually would.

So, does anyone have any input as to what the problem might be and what can be done about it?

Edit: It still did a 12.5@115mph for what its worth

yea it didnt sound the best last night ey man, my money is on the flex plate tho. As its torward the rear of the motor.

ummm get the tune back to stock

and take it to fraud... WARRENTY

2003, wouldnt it be out of warranty?

mmm be close....

Yeah it's out of warranty and it can't be flashed back to standard anyway because of the bigger injectors. Good luck getting warranty on a drivetrain on a modified T anyway.

hahahahaha

good luck....

i had a similar thing with my ef mont and what it was was the touqre converter bolts where loose due to the bearing been f**k out , is your man or auto

yup my guess would be torque converter bolts loose
pretty common on the BA's we've had a few like that come in at work

WOW! 12.5!

That's brilliant!

Shame about the break.

i too put my money on torque converter bolts. i had one go and it was there then gone, and up in the revs it dissapeared. then i ended up with 3 missing and it was an all mighty rattle, kind of like the sound if the starter didnt disengage properly

It just seems a bit strange that the car still has drive, I thought if one bolt went during a flat out run the rest would go quick smart too. We'll soon see

undo the flap at the bottom of the motor and look in, spin the motor by hand and see if there is any bolts missing or sitting at the bottom of the box.

its the easiest way to tell without pulling the whole motor out

Looks like it was the flex plate after all. It's got a fair bit of play in it and it doesn't seem to be turning the crank when turned by hand. No bolt fell out of the access plate though..

well i don't know the setup in the new falcons but i done 6 flexplate in 6-7 months and finally last night got p****d off with it and ripped the motor out and stripped it down to find the crank moves around 1-2 mm end float. not a good thing, bearing ain't really good either but haven't spun any.

I have an el 6 cyl. with only 130 000 on the clock. was also running a jim mock stall. it was the bolt on the back of the crank that came loose. Probly the same thing on yours.