Quaife and ZF... What difference?

[SprintStar]

Hello All,

I know the ZF is clutch-based whereas the Quaife is gear-based. Which is better? And are both LSDs? I thought the Quaife unit is some torque-biasing differential? Is that the same as a limited slip differetial?

Many thanks.

SprintStar.

[lightning bug]

A Quaife is an LSD. As you said it uses gears. The ZF uses clutches. I was told by Rennsport (who is building my 915), a ZF style diff is better than a Quaife in a rear drive car for longevity and performance. The gentleman I spoke with has a 911 w/ a ZF style (Guard Transmission) LSD and a Quaife in his GTI. Go to: www.rennsportsystems.com They will be able to explain better than I. What trans. are you installing??

[SprintStar]

Originally posted by lightning bug
A Quaife is an LSD. As you said it uses gears. The ZF uses clutches. I was told by Rennsport (who is building my 915), a ZF style diff is better than a Quaife in a rear drive car for longevity and performance. The gentleman I spoke with has a 911 w/ a ZF style (Guard Transmission) LSD and a Quaife in his GTI. Go to: www.rennsportsystems.com They will be able to explain better than I. What trans. are you installing??

I have a '73 Super and currently he has got the stock gear box in him. My options are :

Run stock box with Quaife.
Run stock box with ZF.
Run Berg 5 speed with either.
Run 901.
Run 915.

Ilm trying to find out about costs... It seems that the Quaife and ZF cost about the same.

And the Berg 5 or 901 or 915 are in the same price league after factoring in bodywork.

I don't know how much the Quaife or ZF will cost for the 901 or 915, but I know I can't afford both the tranny AND the LSD at the same time. The LSD will have to be added later. But it does adding require me to drop the entire gear box?

How much work extra is it to fit the 915? I heard it's stronger, but also longer and heavier? Would that cause the car to ill-handle?

I'm still undecided to go with Quaife or ZF.... I heard some bad things about clutch-based LSDs but since ZF is OE to even Porsche, they should be good? Did the gentleman explain exactly what makes a ZF better? Thanks!

Sprint.

[lightning bug]

The LSD I'm using will be a Guard Transmission ZF Style. Its a cromoly housing so its strong. Its like the strongest on the market. It runs around $1700 for the 915. He really didn't say why the ZF syle was better. I'm still going back and forth with e-mails to him. Where did you find a ZF for a VW box. I know Kymco used to sell them, not sure if they still do. I don't think you'll have any handling problems with the 901 or 915 install. I'm still researching my 915 install. Should have it done in a month or so. I want custom gearing but can't afford it right now so I'll run a stock ratio 3:88 915 for now.

[SprintStar]

Originally posted by lightning bug
The LSD I'm using will be a Guard Transmission ZF Style. Its a cromoly housing so its strong. Its like the strongest on the market. It runs around $1700 for the 915. He really didn't say why the ZF syle was better. I'm still going back and forth with e-mails to him. Where did you find a ZF for a VW box. I know Kymco used to sell them, not sure if they still do. I don't think you'll have any handling problems with the 901 or 915 install. I'm still researching my 915 install. Should have it done in a month or so. I want custom gearing but can't afford it right now so I'll run a stock ratio 3:88 915 for now.

I've always wondered about gear ratios... How come the 911 use r&p with 7.something and 8.something? Shouldn't they be like 3.88, or 4.125 or 4.375 or similar like in a Bug? Are the gear ratios different altogether?

Woohoo... You are spending a LOT on your tranny! Impressive!

Met someone selling ZFs for the VW box. Just got to emailing him. Details as I know more....

What's your ride anyway?

Sprint.

[Steve C]

Hi

Im using a quaife, what made me decide to get one was its lack of maintenance needed, the ZF needs attention if its screwd up a lot and the quaife works like an open diff until its needed and when it starts to work its very gradual keeping you in control.

Steve C

[SprintStar]

Originally posted by Steve C
Hi

Im using a quaife, what made me decide to get one was its lack of maintenance needed, the ZF needs attention if its screwd up a lot and the quaife works like an open diff until its needed and when it starts to work its very gradual keeping you in control.

Steve C

How much lock did you specify on your Quaife? How much did you pay for it? You're in Australia?

Hmm... The ZFs can be rebuilt? Or should they be junked? I'm actually trying to find some from a 181 tranny. :-)

[lightning bug]

The ratios you're talking about are the ring & pinion ratios. Porsche usually refers to them by the # of teeth on the pinion gear and ring gear respectively....... ie 8:31. 8 is the number of teeth on the pinion gear and 31 is the number of teeth on the ring gear. For most cases (in all vehicles), the pinion gear will have less teeth than the ring. A 915 came in either a 7.31, which is a 4.43 and a 8:31 is a 3.88. This is calculated by simply dividing the ring gear teeth by the pinion teeth. ie. 8:31..... 31/8= 3.875 or 3.88. Also try www.phii.net They have a list of pretty much all of the gears available for the 915. Weddle should have what you need for the VW stuff. Yeah... my trans is gonna cost me. That's why I'm running it stock for a while. Changing every gear but 1st. ZF's can be rebuilt. ZF's are becoming harder and harder to find. But there are companies that make the same style diff. Quaife's in the US cost around $1100. for the VW. Not including the labor. Good Luck and keep us posted on the VW ZF's. Thanks!

[SprintStar]

Originally posted by lightning bug
The ratios you're talking about are the ring & pinion ratios. Porsche usually refers to them by the # of teeth on the pinion gear and ring gear respectively....... ie 8:31. 8 is the number of teeth on the pinion gear and 31 is the number of teeth on the ring gear. For most cases (in all vehicles), the pinion gear will have less teeth than the ring. A 915 came in either a 7.31, which is a 4.43 and a 8:31 is a 3.88. This is calculated by simply dividing the ring gear teeth by the pinion teeth. ie. 8:31..... 31/8= 3.875 or 3.88. Also try www.phii.net They have a list of pretty much all of the gears available for the 915. Weddle should have what you need for the VW stuff. Yeah... my trans is gonna cost me. That's why I'm running it stock for a while. Changing every gear but 1st. ZF's can be rebuilt. ZF's are becoming harder and harder to find. But there are companies that make the same style diff. Quaife's in the US cost around $1100. for the VW. Not including the labor. Good Luck and keep us posted on the VW ZF's. Thanks!

Hehe... I see! Thanks for the explaination! :-)

And can you keep a secret? I scored a Quaife LSD last night.... 1500miles, $550! I'm so happy! *grinning like a silly school boy*

Let me talk to the ZF guy more and I'll post his contact here. Come on, a show of hands, any one interested?

Sprint.

[lightning bug]

NICE SCORE!! Good Luck with it. I may be interested in a ZF. They are for T1 boxes right? IRS or Swing? Thanks!!

[petevw]

Originally posted by SprintStar


And can you keep a secret? I scored a Quaife LSD last night.... 1500miles, $550! I'm so happy! *grinning like a silly school boy*


Sprint.


congrats,

thats the one i wanted!!
did you see my thread: "will this quaife diff work in my tranny?"

oh well....

later,
pete

[SprintStar]

Originally posted by petevw
congrats,

thats the one i wanted!!
did you see my thread: "will this quaife diff work in my tranny?"

oh well....

later,
pete

Hehe... You were asking if it's for the T-1 or T-2 splines, right? Come to think of it.... I didn't ask him that. But I'm on my stock 3.88 tranny so I think it should be ok?

Sprint.

[lightning bug]

I'm in the process of moving and while cleaning up, I found an e-mail from 8-02 from Rennsport that I printed. As you can see, I also wanted the Quaife. Here it is quoted:

Hello again Steve. Yes I would want an LSD. I don't know if you use Quaife or ZF. I would prefer a Quaife. Do you suggest otherwise?

Uhhh, yessir by far. IMHO Quaife LSD's are fine for FWD and street cars, but for any track work and in any high-power situation, the clutch-pack type LSD's are far superior. They lock up better and under trailing throttle, they keep the rear wheels connected to stabilize braking and corner entry. The handling differences are quite dramatic. I only use Quaife-types in FWD cars that cannot tolerate ANY additional understeer and in cars that are autocrossed.

Steve Weiner
Rennsport Systems
Portland, Oregon
503.244.0990
E-mail: porsche@rennsportsystems.com

[SprintStar]

Originally posted by lightning bug
I'm in the process of moving and while cleaning up, I found an e-mail from 8-02 from Rennsport that I printed. As you can see, I also wanted the Quaife. Here it is quoted:

Hello again Steve. Yes I would want an LSD. I don't know if you use Quaife or ZF. I would prefer a Quaife. Do you suggest otherwise?

Uhhh, yessir by far. IMHO Quaife LSD's are fine for FWD and street cars, but for any track work and in any high-power situation, the clutch-pack type LSD's are far superior. They lock up better and under trailing throttle, they keep the rear wheels connected to stabilize braking and corner entry. The handling differences are quite dramatic. I only use Quaife-types in FWD cars that cannot tolerate ANY additional understeer and in cars that are autocrossed.

Steve Weiner
Rennsport Systems
Portland, Oregon
503.244.0990
E-mail: porsche@rennsportsystems.com

Sigh... This is the part I'm confused.... Will the clutch-pack type work well in a street car? Is the factory ZF LSD considered good enough for street? I sure don't think VW intended folks to track in Bugs! :)

And the Quaife is good for autocross? Isn't that sort of similar to track? Pardon my ignorance. I take my Bug to the track and also want to join auto-x events.... What's good? Quaife or ZF?

*scratch head*

[lightning bug]

I'm not absolutely sure myself. I put Steve's e-mail there for anyone who would have questions. I haven't built my trans. yet, but when its time, I'm sure I'll ask many more questions many more times. Keep in mind that Rennsport is strictly a Porsche tuner and this e-mail was regarding a 915 build, however a Bug has the same general similarities. IMO I believe the Quaife is definitely better than stock for any type of driving, the ZF style is just apparently better in some situations. You really have nothing to worry about. Didn't mean to alarm you..... just for reference.

[SprintStar]

Originally posted by lightning bug
I'm not absolutely sure myself. I put Steve's e-mail there for anyone who would have questions. I haven't built my trans. yet, but when its time, I'm sure I'll ask many more questions many more times. Keep in mind that Rennsport is strictly a Porsche tuner and this e-mail was regarding a 915 build, however a Bug has the same general similarities. IMO I believe the Quaife is definitely better than stock for any type of driving, the ZF style is just apparently better in some situations. You really have nothing to worry about. Didn't mean to alarm you..... just for reference.

Hehe... Thanks for the note. Does anyone have input or thoughts about this? Since most of us run street car (instead of track only), would the Quaife make more sense?

Sprint.

[MattKab]

Is it the case that the Quaife was developed for motorsport and the ZF for mud/sand/snow?

Quaife has a better website than ZF :D

I've sourced a ZF with cryo'd discs and 181 'flanges for my '79 T1 and I need to make a decision sharpish:confused:

Matt

[SprintStar]

Originally posted by MattKab
Is it the case that the Quaife was developed for motorsport and the ZF for mud/sand/snow?

Quaife has a better website than ZF :D

I've sourced a ZF with cryo'd discs and 181 'flanges for my '79 T1 and I need to make a decision sharpish:confused:

Matt

Well, if you do decide to give up on the ZF, let me know. I'm interested in it. :)

Sprint.

[Bruce2]

Come on Matt, either sh!t or get off the can!!! ;-|)

Guys, I have more than one IRS ZF, talk to me.
But don't e-mail me at the addy I'm registered with, I don't use it. Instead, use this one:

brucetweddle@canada.com

[MattKab]

Do you use one yourself Bruce? (ygm)

Matt

[Bruce2]

I've had the one in my car since '96. I've since driven it about 130,000 km.
I lock it up every day:)

Someone above talked about the maintenance required by a ZF. Other than changing the gear oil, I've done nothing.

[MattKab]

That'll do for me.

Email me the neccessary :)

[effvee]

Hi, I have a Quaife for the IRS. Let me say "it one well made carrier" I have not installed it and I will be doing the rebuild. I will get my parts from Long Transmission. I bought a jig from a friend for 50$ without the gauges and I will get the gauges from Long. Between the Berg book and the Bently manual I should be able to do it. The quaife and and fifth gear from Wheddle will do it.