For an AX car with some fast street driving, is it worth the $2000 for a LSD? The tranny is out and being totally rebuilt. That's some serious coin on top of all of the rest of the money being spent on this car.

do you want to compete? or just show up and play?

LSD makes a difference

Somebody correct me if I'm wrong here. Quaife - yes, LSD - no?

Quaife=YES LSD =YES

either option is better than an open dif.

Quaife? What's the difference?

Quaife/Torque biasing unlocks on decel

LSD (disc or plate type) works in both directions

I thought the difference was that quaife used gears to eliminate wheel spin, and LSD used friction and could be ordered in different ratios. Also that quaife lasts longer.

yes the quaife/torsen/torque biasing dif uses gears

the plate LSD uses shim plates to keep the dif locked,

the quaife.. etc works when you are driving against the gears.. ie accelerating. although as soon a you brake the dif opens...

the plate keeps the dif locked to a percent, whether accelerating or decelreating

If you've got the bandwidth, this article might help.

http://www.nosubstitute.org/articles/LSD_V...Velocity_Feb01/

I can PDF it into a smaller file Monday if that would be helpful to anyone.

Or if you have bandwidth now and want a cleaner copy (PDF of entire Velocity issue), here ya go --

http://www.nosubstitute.org/articles/Veloc...01/february.pdf

So you have $1295 for a quaife, and $2000 for LSD. Which should I hang on my car? It will have a freshly rebuilt but stock 2.0.

What is your current/intended use for the car? I think conventional wisdom is that for autox the TBD (i.e. Quaife type although GT makes them too) is fine or even better; and for track use you want a real clutch type LSD. For street, honestly unless you are traction-limited due to massive torque or slippery conditions, the cost-benefit is tough to justify IMHO.

Whichever way to go, be sure to email or talk to Paul Guard (GT Transmission) as this is his specialty and his diffs are top notch.

(edit) oops I just re-read your original post where you say AUTOX. I do not have a ton of autox experience but again I think a Torsen/Quaife type TBD is generally preferred for that usage.

From what I know I'd go with the quaife. Nobody addressed my question about wear. If the quaife is gears, and the LSD is friction can you guess which one will wear out first?

I would go with the LSD.. and spec it at 80/80

but that is if it were for my car.

A quaife is a great dif... and may be everything your looking for

In the article the author states that the torque biasing style is vastly inferior. I assume the quaife is considered a torque basing diff? So this seems to be cut and dried in favor of lsd or "always on" There goes another $750. Bring on the LSD Mr. B!

80/80? I thought it was a ratio? You know, adds up to 100. Like 70/30, or 80/20.

Good point re. wear. If you drive your car on the street a significant amount then this would be a factor. IIRC Otto told me they use to set up the ZD LSD's at near 100% lockup during rebuilds because then they'd soon be at the desired 80% and loosen up through the year; then rinse & repeat for next season. I suspect the new units with improved materials & techniques may hold up a bit better but they are still friction based mechanisms.

Then again, there is a point on the slippery slope of autox or TT or race competition where you are most likely tearing down the trans every season or two anyway...in which case the cost delta between diff types is probably not huge.

Intended use? I would like to put in shit loads of seat time along with my son next year in AX. I would also like to do some type of DE this year to improve my skills. I only attended one event last year and I am pretty well hooked. So I want to have this car set up right!

this is a timely re-address thread...
I'm working out the details for a different race tranny and had a long chat with my race guru out here, Alan Johnsen..

I had always thought exactly the above: LSD=track and TBiasing=autox

I do (did?, dang its been a long time building this new car) track driving, and even have a locked diff in my current race box that I just got freshened....

So long story short, I met with Alan and he insisted that with my small motor (2.0S/6) that I don't want to run a LSD, and will ultimately be faster with the TB....

he said that in the lower HP applications, the LSD is creating too much loss
further the TB would be smoother again for the lower HP situations....

I've got to say I trust this guy implicitely...
when he built my Locked diff tranny the first time, he cut my personal best by 2 seconds... I'd put his advice against anyone out there...

so like I said I'm a little bit befudled... I'm going to go ahead with this furture box.. It's pretty trick as you loose reverse but move 2nd down into that slot.. I'm going to go with his advice and put the TB into it. Guess I'll see how it compares to a 100% anyways.

brant

An open diff is best in a low hp car. The only losses are at the wheel/'pavement interface, which should be controllable with the driver's right foot. This is especially true for DE. At an AX you may feel otherwise.
A LSD or TB diff will have internal friction losses and consequently will heat up the gearbox.

what do you consider low horsepower? less than 200?

I'm putting one in my V8 box....

If you want a competitive autocross car, then you need some sort of LSD, either kind will do and depending on who you talk to one better than the other.

The difference is inside tire spin. If you are getting all you can out of the car, and you are spinning the inside tire on tight turns, then you can probably benefit from a LSD. If not, then wait until your driving skill exceeds the performance of your car.

If you are rebuilding a transmission for a performance/competition application, you are wasting money if you don't pop for a LSD. C'mon what's another $2k???

A LSD will help improve traction, but it will also change the way the car handles. As an 'ol red neck hot rodder told me "a posi rear end will make it hook up". Detroit used to call a limited slip diff "posi-traction".

Chris F.

what do you run for a diff ?

brant

Open.
I currently have about 125RWHP and haven't found any need for a change yet.
I have a factory lsd and plan to build another box around it to go with my next engine that I hope will have more like 155+RWHP. Other 914 guys I know in FP are running fully locked. There aren't too many corners where I race that the limited slip will benefit me, and I'm not sure the benefits will outweigh the liabilities.

Up to 150 anyway.

REMEMBER -If one of the rear wheels loses contact with the ground, as in a really tight A/X turn, the Torque-bias diff STOPS working and the wheel spins. The ZF will continue to supply power to the wheel on the ground.

The ZF will work in ALL conditions - the Torque-Bias works in limited conditions.

I think the choice is clear.

Ken

True...just another reason to run withOUT a rear anti-sway bar on tight AX courses.

I thought the choice was clear in the past also...
but now I don't know if it is that clear anymore...

I'm told that at 160hp (flywheel)
I will get better times with a quaffe than a clutch/zf lsd...

so ultimately the fastest time is what I'm after.

(and I picked up 2 seconds with a locker versus open using the same pair of tires in my old 130hp-flywheel motor)

I've been told that the break is around 200-250 hp.
the 914 race shop here locally, builds their 250hp machines with 915's and ZF's, but recommended the TB to me with a 901.

I'm not arguing, just looking for lots of input.
brant

I, too, am researching the options.

I've run lots of Quaife torque biasing differentials on fwd cars on the track and auto-x. I have had wheelspin on tight corners, but that's on a front driver. If your lifting the inside rear on a 914, I think there's some suspension adjustments that can be made to reduce that.

I'm leaning towards a Quaife because of corner entry. I don't like the thought what the ZF does to the corner entry balance of the car.

Also, I used to run my mild 2.0L 914 (certainly no more than 110 horsepower) on street tires with an open diff at auto-x's. Huge wheelspin due to the low end torque of the engine. Now, having said that I've run the same engine and trans with race tires and haven't spun the tires on the race track yet.

what class is your car going to be in?

i THINK that running LSD will put you into Bp in PCA. it will earn you another 30 points in the new point system.

neither of which are bad per se (it's a stock engine class anyway), just make sure you look before you leap!

Class? not sure...car will have:
new shocks koni yellows
new springs
rebuilt 2.0 with stock FI using "better grade" of parts IE ceramic lifters and fancy headstuds
replace fuel lines
rebuilt tranny
shift conversion
ssi's
bursch
probably will upgrade tires, but no flares planned as of yet

So whatever class this puts me in for the SF bay area ax scene. I would like to run 5-10 events next summer and would like to be competitive! Interesting that there is a 50/50 split of opinions on this. I am having the work done by a shop I trust, and their recommendation is the $2000 route but they wisely caution me to "do the research". I have the $2000 budgeted, but is the more expensive option better for my intended use?

I can see there would be an advantage to a LSD in deceleration situations where the traction might vary between the right and left wheel. ie- a patch of oil, running one wheel into the dirt. But, don't you always accelerate through a turn? If the quaife is on only during acceleration, and the LSD is on all the time, under what situation does this difference apply?

what spring rates?

stick to 140 rear springs, add a 19mm bar, add sticky tires, and you'll be in Bi.

getting more aggressive suspension than that will put you in Bp with me, trekkor (scratch that -- he's doing the /6), darren, howard yao and others. you can also have a header in Bp (most of us do). again, LSD might put you in Bp, so do check. i don't know who in Bp has LSD. i don't, but i'd sure like it!

either class is fun and usually has at least 3 cars. Bp has had like 5+ the last couple AX's.

budget for tires, alignment, and corner balance before you put down money on LSD. you can be competitive without LSD -- you'll get your ass kicked without tires.

Nathan,
The motor and tranny are out now, so it's decision time. I will go with one style or another. There does not seem to be any concensus, so I will probably go with my shop's recommendation.

Hi Pat,

I went through the same thing as you are last winter. I decided on a Paul Guard ZF style LSD with 80% lock. If you're serious about taking it on dual purpose on the car (lotsa auto-x and some DE/Time Trials) I think you will like the LSD. I really enjoyed driving the car after I got used to it.

Keep in mind that I had a 2.7 liter 6 with ~230HP, so I could lite up the back pretty easily. But I also found that having the LSD not only helped me in Auto-x, but really helped at the track, I could feel the car not as wiggly when on the brakes hard after a fast section. I'm sure it's all preference, and I've never driven a TB type, but I prefer the LSD to an Open diff. It takes you a few runs at the auto-x to get used to the understeer of an LSD, but you adapt pretty quick and then you can feel the difference.

Just my $0.02!

And if in the back of your mind you're going to put more poop in the motor (150hp+) you'll really like it!

Bill P.

I heard a rumor at the FFC that some of the 914's delivered to the midwest and some of the snow covered parts of the country had factory LSD installed. Is this true and if so What years was this offered?

WOW cool man, I can see trails, LSD it is.

check the classifieds. someone has a line on quaiffe's

I guess I am still a newbie teener owner. What is this LSD?
Where can I finds some?
How much does it cost?
How much do I need?
How fast will it work?

Um.... I think I got confused about what I was asking about.

Let me start over........
What is this LSD?

Limited slip differential.....LSD. Like a "locker' rear end on a 'murican car.....makes BOTH drive wheels spin at the same time. Equal power and more balls out of a turn.

Kinda like a two handed booby grag.....

Lets try this again... Anyone know if this is BS..

Rick,

no... I've always heard it was true..
problem is that it seems to have been very few.. Not sure if anyone has even seen one... but they apparently were listed in the factory options....

I once saw a option code, or tranny number or some such way to identify if this was included or not..

If there are even any out there, probably the owner of said tranny wouldn't even know it since the clutch adjustment is probably long over due...

Same diff was available on 911's of the same era..
those can be found used and rebuilt.
I remember looking at a rebuilt used one from Car Quipt a couple of years back... think he wanted only 300 less than the new ones were available for at that time.

brant

So, what's the going rate of a LSD, like the ZF or something.
I noticed that the quaife is in the classefieds for about $850 or less:
914club GB offer on quaife
Are the benefits of a ZF at the track worth the price difference (if there is one?) Thanks, just thinking of stuff I'll need when I upgrade the HP.

Normal trans have an HA prefix, the LSD had a HB prefix as part of the serial number.
Not to say it is still installed. Somewhere in my lit I've seen references to quantities, but it is very low.

Both styles: ZF and TB are available through Paul Guard (or the TB through Quaffe) for about the same price.

figure 1200 to 1400 depending upon the source/weather/what ever....

The group buy at 850 sounds somewhat unrealistic. Don't get me wrong.. I'll be the first to send the money and I want one at 850, its just that I'm skeptical that the company of Quaffe will be willing to make this offer....

NOT much price difference...
If your making long term plans, make sure you factor installation into the cost.
Installation is not trivial, and a bit more indepth than just changing syncros on a tranny.. I only guessing but believe that most shops would charge $300 - $500 installation.

Also, I would like to re-iterate that it is not clear there is a benefit of one style over the other at a track situation.
Depends upon your personal preference, HP, type of corner, driving style, etc....

(I always heard and thought it was a clear decision, but at least my personal opinion at the moment is that it is not clear for most applications and I would love to see actual data or time sheets of comparisons)

brant

I just bought two from GPR at 1200 each and sent them to Red Beard.....he's keeping one and th eother goes in my V8 box with the H gear....

Dave said that was the best price he could do as there is nt much of a markup on it from HIS price....

So any $850 units are far from realistic.

BTW...the Guard LSD is a Quaife copy....prolly around the same price....rumor has it...Quaife was NOT happy about the copying....

Mike,

I still want one at 850, but I fear you are correct...
I have a relationship with the local race shop that often undermines the going prices of items...

I asked them for the special price and they said that Quaffee, won't sell them cheaper and there is nearly no mark up...

I know ricer places sell diffs for ricer cars for half of a porsche diff.. I'm guessing that the group buy thread about the ricer shop trying to get us a deal, is based upon their familiarity with HONDA prices....

Still I'll be the first to send $850, if it comes to fruition.
brant

The certificate of authenticity for my car says it was delivered with an LSD. It was gone when I got the car. I use a ZF type LSD set up at 40/40. Just enough to stop any inside wheel spin but not enough to affect turn in.

I've participated in a group buy for Quaifes before. We bought 2 for VWs and a couple others bought some when we did. The price went from ~$950 (at the time) to $825 because of the group buy.

For some reason, that's how Quaife does business with some people (my guess is anyone who calls them or their distributor about it). I don't understand it, but have witnessed it and believe it can happen.

Wow prices sure have gone up!

When I was in high school window pane or purple micro-dot was like $4 a hit.....