Different Spool

[chev z]

Raced the wide bottom V8 240z last Monday at Winton.I let a fellow driver test my car out for a bit of fun , after he had lowered my best lap time ,1 min 35.5 sec , to 1 min 33.6 sec ,he suggested that I replace my lsd clutch diff to a spool diff .What do you guys think?

[dat2kman]

Pure track car? Then yes, but you may want to redo geometry settings, as a spooler will want to give you a bit f "push" understeer into corners.

It's fun to drive on them, just get the back end a bit "loose" so it can get a tail out going into a corner.

Very easy to make an existing open diff f your choice into a CIG lcker.

Lots f amps, and a couple of 8mm thick rectangles of steel nestled down amongst the spider gears.

 

Always carry a spare halfshaft though,,,,

[260DET]

A locker would not suit me, it depends on your driving style to some degree but no pro race cars use lockers. Maybe the present slippy diff needs tightening up a bit. Still it's not an expensive option to try.

[chev z]

Yes, my Z is a pure track car.also the extra RWKW 346 and 750 nwwt torque probably has made the clutch pac diff lose its lsd capabilities.l must add that after my new best racing mate had given my car the test I went out and beat my best run by achieving a PB of 1min 35.37 sec I had a in car camera recording his laps and am hoping to copy his lines and braking areas to reduce the 1.7 sec gap to his best time. NOW for the highlight of my day .....it was a very approachable JOHN BOWE that had a drive for seven laps. Really good bloke and suggested a few improvements that he thinks could give me or car a further 1.5 sec a lap time reduction. I'm still on a high.

[dat2kman]

A locker would not suit me, it depends on your driving style to some degree but no pro race cars use lockers. Maybe the present slippy diff needs tightening up a bit. Still it's not an expensive option to try.

Apart from all the pro race cars that do use spooler diffs,,,,

V8's

Sports Sedans,

Group C and A tourers,

Muscle Car Masters/Biante

 

Mostly bg powered stuff, that rips clutch packs and Torsen style diffs apart.

[luvemfast]

I'd take Bowes advice over Richard's any day!

Awesome stuff Steve 

[chev z]

So do we go with a mini spool or full spool. Also anyone know where to buy one and approx cost.

[luvemfast]

So do we go with a mini spool or full spool. Also anyone know where to buy one and approx cost.

PM sent 

[Gordo]

Nice one Steve. Did John like the zed, bet he hasn't driven many before.

[260DET]

V8 Z for the win anyway

[chev z]

JB was only going to take her out for a couple of laps , so to stay out and do 7 I think means he was enjoying it. I offered the drive to him after the March S he was testing was put into a wall early on , NOT by John Bowe.He actually asked what I wanted him to assess, I gather any car setup tips etc. I said to drive it if he wanted and to have some fun.Once I get the video ,I will try to put it up on this site. I must say he gave his evaluation of the car that even i could understand , overall he's just a top bloke. One aspect of the car under brakes, ie feeling light in the rear and slight swerving side to side was put down to the lsd not functioning properly hence the idea to go with a spool diff. It still amazes me that a person can jump into any car and get it to perform so well , makes me a bit envious but hugely impressed.Well done MR John Bowe and thanks.

[Gordo]

Great stuff. I think all owners of race/ club cars would love the opportunity to have experienced drivers give an assessment of our pride and joy. Very Envious .

[chev z]

Well it's been nearly a year since JB had a drive . I took his advice and after a million phone calls we eventually located a spool diff in the US of A.

So last Saturday I ventured out to Winton to give it a try out.

I quickly discovered that having a locked diff totally changes the way you negotiate corners,so after a bit of experimenting I found that by braking hard and then accelerating gradually basically straight away (no coasting) the Z would turn in .

 

My times then improved dramatically to record a new low of

1min 33.87sec .

 

I was stoked at this time , so went home really pumped .I decided to check out John Bowes time last November and compare my new time against his , this is where my excitement turns to a mixture let down and then fist pumping rapture.I found that I had misread last Nov times and that I had actually only been 7 hundreds of a second behind JBs time, which means my new time isn't a new record for me at all around Winton.

Before you all go ,how could you misread a time sheet . In my state of JB awe I totally forgot about using two different transponders, hence two lots of times.

 

So can you racing guys give me anymore driving tips with a spool diff?

[260DET]

Sorry, I don't know of anyone who uses one in a Zed. Did John Bowe recommend using one?

[dat2kman]

Just like driving a locker, you have to fair chck it into a corner, wrench it around, and nail the gas, hard.

Drive t like a bg girls blouse, and it'll jst understeer you off.

You need to have the front end set up with a little toe out, or 0 toe, t'll turn in a lt better.

Spoolers/lockers are fun, on crcut, but even mre funner in a bg hp dirt rally car.

 

On/off type ratchet diffs, aka Detriot Lockers, also require reset front end geometry, if the car is used hard.

[chev z]

JB recommended a spool diff ,get a expert to tune the suspension and definitely get bigger brakes.

As I listened to his list I mentally added up the overall cost and reckon I wouldn't get much change out of $10000.

So took the cheapest option, the spool diff.

By the way , he was spot on about the lsd diff breaking down under brakes.I don't have the rear end side to side wobbles anymore.

[luvemfast]

Sounds like some progress has been made and new driving style required.

But......

All means nothing without some video Steve! 

[TomC18]

The red Zed runs locked diffs. Works just fine but you do have to drive it hard as Jas says get the front turned in and drive through the corner. Mind you that's easier with only 300hp. Used to do 1.30's at Winton on crossplies so it would be interesting to see what it would do now with radials and the resurfaced track.

[260DET]

As Jason said a bit of toe out at the front may be needed to get a spooled car to turn in which ironically may bring back the former instability under brakes and a general tendency to wander around a bit. Personally I don't like making a change that will likely be negative too when there are other options but as always there is the budget. Sounds like with a spool it's up to the driver to maximumise the benefit and cope with the negative.

[chev z]

I had a in car camera when JB was driving , I suppose it would be like watching me but .007 secs faster LOL. So I could put that up here with someones help Simon

Edited August 31, 2016 by chev z

[Gordo]

Great job Steve. Just goes to show, we all think we can drive (race a car) but there are so many different ways to acheave a fast lap. I would say less than half of us know how to set up a car that handles reasonably good. Even a road car. Maybe 10% could get it good. And the rest are keyboard racers. JB has been around and raced all sorts of cars. He is right up there with the best at setting up cars. It's amazing how he can pin point the things that will work. Something's you would never think of. Imagin if he could drive it again, what else he could suggest.

And great times buy the way. Hopefully you can get some time off the farm and come down to PI with the zed boys.

[chev z]

Gday Gordo ,I think one of the reasons for the better times is knowing what the car is capable of after a great driver sets a lap time in it,gives one confidence in the machinery.I was also able to get some hints about certain aspects of the track eg instead of going through the esss at the end of the main straight in 3 gear stay in 4.

As for going to PI ,that will have to wait, as I am in the Over 60 Victoria cricket squad to play in Perth this Nov for the states national title.So a catchup will have to wait unless I can combine a match down that way and race as well.

[260DET]

Knowing what the car is capable of in the hands of a top driver is a good point and a great benchmark. I'd happily hand mine over for that purpose although it still to some degree involves a personal preference. Where is that video? The only way I know is to upload to YouTube and then link it here.

[hmd]

Steve,

 

You need to be mindful about comparing Nov 2015 and current times as the track resurface has lowered most people lap time. 

 

There were 6 new lap records in a recent Group S race there in August. Some record was lowered as much as 2 seconds.

[chev z]

hmd I think you have misread the times I am comparing , JBs time and my time that is .007 sec slower was on the same day . My time last Saturday was approx .3sec slower on the resurfaced track with the new spool diff , hence my question about driving styles with a spool/locked diff.