how much can a stock FD differential handle?
03-18-07, 05:15 AM
#26
Senior Member
I've blown my Torsen with near-stock power levels. I over-revved at a launch....spinning my wheels at 7000rpm. When I let off the gas...it went *BAAAAAAANG*. Needless to say, I don't dragrace anymore.
When driving, it would "limp" with a *kadunk, kadunk* every wheel revoluntion.
I now have a noisy-*** Kaaz.
When driving, it would "limp" with a *kadunk, kadunk* every wheel revoluntion.
I now have a noisy-*** Kaaz.
03-18-07, 09:44 PM
#28
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Originally Posted by moktan_fdtt
so Its the Diff or the powerplsnt frame?
Originally Posted by Rynberg
If you want to know what's really broken, you need to get the car up on the lift and start inspecting.
03-19-07, 03:22 AM
#30
Originally Posted by Mahjik
There is no way in hell the stock FD diff will take that kind of power on drag radials or anything else which will allow it to hook up on a launch.
The only way would be to use some tires which would allow the car to spin on the launch as to reduce the shock to the diff. However, that's less than ideal with drag racing. People have been breaking the stock FD diff anywhere in the 340-400 rwhp range when using drag radials.
The only way would be to use some tires which would allow the car to spin on the launch as to reduce the shock to the diff. However, that's less than ideal with drag racing. People have been breaking the stock FD diff anywhere in the 340-400 rwhp range when using drag radials.
What I posted is very true. The v8rx7 community talks about this all the time. As most of our cars put down more than 400 whp. I personaly put 430 at the wheels. I have a TII diff with 300m axles and have run my car several times with E/T DRAG's. No problems at all.
The stock dif will stand up to 400 whp for a year or two, even if you go to the quarter mile track every now and then. A TII torsion or KAZZ fix all internal problems with the diff down to low 9's. But at low to middle ten's you start breaking axles. The 300m axles are also proven down to low 9's.
But the real problem with our rear end is wheel hop. Thats what breaks diffs. Lots of people have been testing the cobra mustang rear end. And there is even one person running a dodge viper rear end in his FD. Both seem to fix the wheel hop issue our cars have with the stock rear end.
03-19-07, 08:43 AM
#32
Originally Posted by rx7what
What I posted is very true. The v8rx7 community talks about this all the time.
Originally Posted by rx7what
I personaly put 430 at the wheels. I have a TII diff with 300m axles and have run my car several times with E/T DRAG's. No problems at all.
03-19-07, 10:13 AM
#33
26.55 psi T04Z Monster
Ive run at 430hp for 3 years and numerous launches with a TII diff w/ KG diff brace and STOCK axles. I also run nitto 555DR as well as M/T Street Radials on occassion.
As for the stock diff: I exploded it as soon as I went single with a good tune!
As for the stock diff: I exploded it as soon as I went single with a good tune!
03-19-07, 11:48 AM
#34
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Originally Posted by finnicky7
Ive run at 430hp for 3 years and numerous launches with a TII diff w/ KG diff brace and STOCK axles. I also run nitto 555DR as well as M/T Street Radials on occassion.
As for the stock diff: I exploded it as soon as I went single with a good tune!
As for the stock diff: I exploded it as soon as I went single with a good tune!
03-19-07, 01:25 PM
#36
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Originally Posted by moktan_fdtt
^ ive been wondering the same, searched but with no find.
03-19-07, 01:36 PM
#37
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Take the best guess and hope for the best, I guess. If I tow the car to nearest shop its about $50 or so... Putting it on the rack and inspecting would probably cost $80 or so, at least 1 hour worth of labor. The cost comes out to be $130,low figures, its not very much. But if someone on this fourm can narrow down the problem, I can save that money and put it towards what I broke.
Again thanks everyone for your input.
Again thanks everyone for your input.
Last edited by moktan_fdtt; 03-19-07 at 01:46 PM.
03-19-07, 01:43 PM
#38
Originally Posted by moktan_fdtt
tBut if someone on this fourm can narrow down the problem, save that money and put it towards what I broke.
1. Get some jackstands
2. Get a floorjack
and slide under to take a look. If you don't have an area to jack up the car (i.e. you live in an apartment and don't have a garage), you are just going to have to bite the bullet and take to a shop.
People can point you into 'a' direction here on the forum, but that's it without seeing the car. The rest is up to you getting dirty. Right now you have two possibilities for problem areas. Now its up to you to eliminate one or the others by physically looking at the car.
03-19-07, 01:50 PM
#39
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Yes I do live in an apartment, but I can still borrow a jack from my friend and look under.
What should I be looking for? leaks from the diff or anything like that? Possible spots to check for?
What should I be looking for? leaks from the diff or anything like that? Possible spots to check for?
03-19-07, 01:50 PM
#40
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Exactly, if you don't have the ability or resources to look at it yourself, there's really not much point in asking about it. Just take it to a shop. Further to that, if you can't even get the car jacked up, why bother asking about how to do the swap? It doesn't make sense to me.
As Mahjik said, we aren't psychic, there's no way for sure we can know what's wrong. You either have to look yourself or get out your wallet, like everything else about the car. Not trying to sound harsh, but this thread has been going on for days and you don't even know what's wrong yet? Just seems silly. :shrug:
As Mahjik said, we aren't psychic, there's no way for sure we can know what's wrong. You either have to look yourself or get out your wallet, like everything else about the car. Not trying to sound harsh, but this thread has been going on for days and you don't even know what's wrong yet? Just seems silly. :shrug:
03-20-07, 11:13 PM
#42
Originally Posted by Mahjik
The V8 guys can talk about it all they want. There are years worth of proof from broken diffs to tell the real life truth (not to mention the ones I've witnessed myself).
Exactly, TII diff (and axles as well), just as I suggested earlier.
Exactly, TII diff (and axles as well), just as I suggested earlier.
You know I would never disagree with you or ryberg if I didnt have lots of hands on experiance with the subject matter
You guys really know your stuff. But I stand by what I posted in my first post to be fact. If you or some others have had trouble at lower power levels maybe somthing else was to blame. Maybe a previous owner never had the rear serviced. Maybe they treated the car like crap. Maybe it was lemon from the factory. I dont know.
There are too many variables to say it will handle exactly X amount of power and then it breaks. I say its good to an area of low 11's high 10's. But after that your on borowed time.
And I agree with you go with S4 TII clutch stlye pack and 300m axle's.
03-21-07, 01:20 AM
#44
Senior Member
Diff teardown thread:
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/differential-teardown-tii-lsd-install-writeup-535290/
Though, the TII diff picture is missing, last I checked.
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/differential-teardown-tii-lsd-install-writeup-535290/
Though, the TII diff picture is missing, last I checked.
03-21-07, 08:52 AM
#45
Originally Posted by rx7what
There are too many variables to say it will handle exactly X amount of power and then it breaks. I say its good to an area of low 11's high 10's. But after that your on borowed time.
The more power, the less time it will take to break. Will it break quicker with 600 rwhp verses 350 rwhp? Absolutely, but that doesn't mean "it can take 350 rwhp" when drag launching. That just means there is a lesser load than the higher HP/Torque application, but still more than it should be handling for its proposed use.
Saying it can handle 10's means that its not going to break, at all. Not "it can handle 10's for x number of runs". That just means it can't handle it because you know its going to fail at some point. That's the situation with the stock diff. I would challenge you or anyone to show us a car that has been using the same stock diff for a number of years and has been running low 11's or high 10's the entire time.
03-21-07, 12:34 PM
#46
26.55 psi T04Z Monster
The biggest thing with the stock Diff is when it does go it explodes half the time. And the case is getting harder and more expensive to find. Especially when you can do a TII installed for less than $400.
11-29-07, 01:29 AM
#47
I think I f#c*^@ my diff up, I was at the track today, on my 3rd run I dropped the clutch at about 3k and grinddddding sound, it would not go foward, i had to tow it home about 30miles, and cost about $200. fu*^. I figure its not the tranny becaause it shifts into all gears smoothly, just when you start to go, you hear the awfull grinding-metal-twisting noise. i dynoed in about 367rwhp, is the stock diff able to handle this?
I'm basically in this same boat. I think I broke my diff (almost positive) tonight at the drag strip. It'll go into gear I can slowly coast to about 20mph, but if I try to apply any load on it (like light acceleration or going up a slight incline I get a horrible grinding and popping noise from the rear. It also happens when I turn. I'll try to post pics of the diff tomorrow (I know it doesn't look normal...just trying to diagnose problem before buying replacement parts) On the bright side though I got 12.60 @ 118.9mph before this happened. Anymore input on this would be greatly appreciated.
11-29-07, 01:41 AM
#48
I'm basically in this same boat. I think I broke my diff (almost positive) tonight at the drag strip. It'll go into gear I can slowly coast to about 20mph, but if I try to apply any load on it (like light acceleration or going up a slight incline I get a horrible grinding and popping noise from the rear. It also happens when I turn. I'll try to post pics of the diff tomorrow (I know it doesn't look normal...just trying to diagnose problem before buying replacement parts) On the bright side though I got 12.60 @ 118.9mph before this happened. Anymore input on this would be greatly appreciated.
11-29-07, 02:07 AM
#49
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what up dude i live in petaluma if u want i can come help u look for broken ppf. shouldnt be to hard. i have tools if u need them i also have my ppf out so u can look at it. let me know. edit this thread way old my bad
11-29-07, 07:36 PM
#50
Will work for horsepower
Im running the t11 diff with brace and stock axles, plus solid trans mount and motor mounts. so far in 2007 i never had higher that a 1.68 60 ft time and a best of 1.52 60 ft. But i know my time is comming to replace something. But not mentioned is the driver mod that problly keeps most diffs from breaking, i dont think you can just go to the line and let her rip. I also run et streets as i belive they help the drive train shock. So far this year i have run tens every time i have gone to the track. Good luck to all!