JoesFC

A friend of a friend is selling a modified gxl differential that I wanted to put into my s5 vert. He wants 250 for it, and claims it's been rebuilt more aggressively. I'm just not sure that it'll be worth the money, after all its still another 280 for install (quote from my mechanic). Will it make that big of a performance difference from my open diff? Is that a fair price for it?

invinciblejets

Install it your self for free. It's really not hard.
What does more aggressive entail? Seems a rather vague description.

Rikk

iTrader: (2)

You should ask your friend to be more specific as most that modify the N/A diffs are simply welding the diff in order to make it solid, unmodded NA differentials go for or less than $100 all the time, T2 differentials go for around $250 most of the time
GL Rikk

JoesFC

He claims it didn't come off of his car, but a friend's. He also says he doesn't know what specifically has been done to it, but that it has "built lsd internals". It's from an 87 gxl, so I'm fairly certain it's not just a welded diff.

RotaryEvolution

iTrader: (30)

is this really a question or are you just waiting for someone to say "totally dude, drop that bad bitch into your car and do some mad drifting!"?

think about it, you want us to answer whether an unknown condition clutch type differential which was rebuilt by god knows who with no documentation to say whether it's a good idea.

i'll tell you the answer, no it's not unless it is currently in a car and you can verify that it works and it is good. aside from that i wouldn't pay any more than what a typical used GXL diff would cost. whether i would gamble on swapping it beyond that point the answer would solely rely on if the labor cost is worth it, if you did the swap yourself then you would only be out your own time and very little money.

i guess the world is your oyster when you haven't been ripped off by people trying to pawn junk on you. the first question i always ask is WHY are they selling it, followed by had badly have they beat the crap out of it and then round it off with was it professionally done and do you have reciepts? if they can't answer one of the questions then i treat the item as broken until proven good.

TrianglePower

iTrader: (1)

Rikk and lyger both have legit answers. I've wondered the same thing myself but unless you get to see the internals and have receipts, you could just be wasting $$. Ps. Self install is cheaper.

rx7racerca

iTrader: (1)

Is this an LSD S4 diff that's been shimmed for more aggressive lockup? That's potentially of some value if you track, drag, or autocross the car, or winter drive it in snow/ice conditions (which I doubt is the case with a vert, but it could be). But otherwise, like Lyger said, no. More aggressive lockup (assuming that's what the "modified" means) would have no real value in a relatively low power car outside of track or low-traction driving conditions. In fact, it could make the car understeer or push more, depending on how aggressive the lockup is (and for sure if it's just welded - in addition to binding that will make the back end hop when turning on dry pavement, and eventually break the diff or a drive axle).

Ask yourself, when's the last time you lit up one tire with uncontrolled wheelspin, and suffered poor acceleration as a result. If you don't know, then an LSD isn't going to help one bit.

JoesFC

Yeah I didn't go through with it. Just a lot of money for something I know nothing about.

jjwalker

I have personal experience as the previous owner of my car had the diff replaced with LSD unit (I am not sure if it's clutch or viscous).

The FC rx7 will already not forgive you when you push it just passed its limit (oversteer). With the LSD, instead of just trying to rip your face off, it's going to try and kill you.

I learned this one night when I got pissed off at someone and tried to leave. I burned out backing out of my parking spot, burned out going forward and took a hard right and did a 180, hit a curb and popped the bead on rear driver tire. Yes, there was 2 nice burnout marks and not one wheel peel.

On an open diff, it gives you a warning you are about to **** up when stressing the car, as the outer most tire will start to squeel right before the car rips your face off. With LSD you have no such warning, the car will just come out from under you.

Moral of the story, don't waste your money on a LSD for a daily driver. First, there is no benefit and secondly, there are a lot of downsides.

RotaryEvolution

iTrader: (30)

in all fairness you have to learn to drive an LSD before just giving it mach 3 throttle and clutch. i like to practice in the rain and at slower speed and in an open area. it will teach you how predictable the car will be when you push it on dry pavement.

jjwalker

I agree, I didnt even know I had an LSD on my car until that event, the previous owner never told me. My first car (truck) had an open diff and it would 1 wheel peel but was great in the rain. The RX7 is somewhat scary in the rain with the LSD and the same on dry pavement. I did make it to work earlier this year during an ice storm due to the LSD. My co-workers CTS, ram 1500, chevy 1500,and dodge magnum didnt make it and couldn't make it.

The RX7 and the AWD BMW made it.

rx7racerca

iTrader: (1)

Do you still have the DTSS bushings in the rear? Besides the fact they might very well be shot due to age/mileage, DTSS makes at-the-limit cornering unpredictable, both because it masks what the rear tires are doing, and because the toe changes it triggers will change as you lose grip, since they are related to how the bushing is loaded. DTSS eliminator bushings will mean a slight decrease in the car's perceived eagerness to turn-in or change lanes, but make the rear much easier to control at the limits of traction.