Sam's build thread

[sambb]

thanks Simon. Its funny how you trust the validity of theory until its your own gearbox and then you start to go 'wait, that better be right that the bolt torque alone will hold it all together!'. The Kaaz instructions that came with the diff only mention torque specs for Honda and Mitsu Evo applications. I'll have to contact them re torque specs for the VW fitments cos obviously now I'll have to be 100 percent correct or I'll always be driving the thing going 'whats that noise', 'whats that vibration' and head ****ing myself that it wasn't done right.

There's two other things playing on my mind. Firstly the fact that if I do go to an 02J 114mm crown wheel and pinion, that I can change final drive. Secondly that I believe that if you fit a 5th gear from a TDi box you can get a proper overdrive gear for the freeway rather than pulling too high revs at 110kph.
Apparently the JDB box I'm building has the same ratios 1st,2nd, 3rd,4th inc reverse as the earlier HWY box I'm running now. So I could go to a punchier final drive but extend 5th so I can still get down a freeway to get to the events. Not sure if that will make 1st un-useably short though as its a split second gear already, but then again with the better diff I may be actually able to lay into it with that gear off the line rather than short shifting out of it. And if I do move away from a k03s to a K03 hybrid (inevitable), a snappier final drive could help driveability and keep me out of lag holes. thinking muchly..

[simon k]

thanks Simon. Its funny how you doubt the validity of theory until its your own gearbox and then you start to go 'wait, that better be right that the torque will hold it all together!'. The Kaaz instructions that came with the diff only mention torque specs for Honda and Mitsu Evo applications. I'll have to contact them re torque specs for the VW fitments cos obviously now I'll have to be 100 percent correct or I'll always be driving the thing going 'whats that noise', 'whats that vibration' and head ****ing myself that it wasn't done right.

I could point you in the direction of a handy reference like this, but it's nice to get it from the source

http://www.boltmasters.com.au/webfiles/BoltmastersAU/files/Boltmasters_Pty_Ltd_Recommended_Assembly_Torques.pdf

[sambb]

more on diffs. I found this article (with links to other articles) about welded front diffs: Welded Differential In A Front Wheel Drive Track Car: Fast And Fun - Race & Track Driving (formerly Win HPDE)
Its pretty interesting actually. It got me thinking about what the lock up % actually are in the plate LSD compared to 100%/welded - is there actually any measure for that? The rallyanarchy links also almost exactly describe the short comings of the quaife atb's (virtually same as wavetrac) which I'd felt so I'm glad it wasn't all in my head.

[metalhead]

Sam, do you reckon Pete would run more events if there were some others in the class? Alex Froedl with the Clio was talking to me yesterday about running the state hillclimb championship next year in Road Reg Under 2500cc.

Ripped one side of the spoiler off my car yesterday at a tar khanacross at Ringwood. Last event for the year, so soon I'll have to pull it apart and fix some things.

[simon k]

more on diffs. I found this article (with links to other articles) about welded front diffs: Welded Differential In A Front Wheel Drive Track Car: Fast And Fun - Race & Track Driving (formerly Win HPDE)
Its pretty interesting actually. It got me thinking about what the lock up % actually are in the plate LSD compared to 100%/welded - is there actually any measure for that? The rallyanarchy links also almost exactly describe the short comings of the quaife atb's (virtually same as wavetrac) which I'd felt so I'm glad it wasn't all in my head.

fark.... maybe ignore the PS: on the email I sent you yesterday

...... looking at a mini diff, then the welder, then a mini diff, then the welder.....

[sambb]

Andrew did you run with the Yoko's yet? Dam I really was hoping to get back up there before the hillclimb season shut down. Huntley is usually the last club hillclimb of the year so I'll see if they have another one. I wouldn't mind running back up that hill again to get a gauge on to what extent it was my FARB (now that I've softened the front off) or just the diff being maxxed out that caused the flighty handling there at that last state round.
Unforunately Pete seems pretty bent on doing the Supersprints based around Eastern Ck and Sydney. He's gone soft with all the state hillclimb travel already. The killer was the lotuses, Matt in the Skoda and particularly Graham Orr in the CRX dropping out all at once which left the <2.5L class empty. Unless Froedel is really developing his Clio (Pete had his measure) I don't think youll see us anywhere other than Bathurst, Ringwood, Huntley, and Canberra for the State rounds next year. I'll do South circuit at the DubNats next year, Wakefield and I'd like to do Ludenham too, so if I plan any of those I'll be in touch for sure.
Reckon you'd come down for a rallysprint? There's one in two days time but I wont be ready - cars good but I haven't entered, don't have a co-driver organised and dont have a leave pass.

[sambb]

Do it weld her up! ha ha While welded diffs might work on flowing tracks I get the feeling that getting the mini to turn on a dime at motorkhanas would be very difficult. No power steering would be the biggest problem yeah. I sent you an email re my diff.

[simon k]

Do it weld her up! ha ha While welded diffs might work on flowing tracks I get the feeling that getting the mini to turn on a dime at motorkhanas would be very difficult.

tarmac motorkhanas may be difficult, I think dirt would be exceptionally good fun

there's this though, not sure what sort of drive he has, but it works well...

No power steering would be the biggest problem yeah.

All taken care of mini on top, Barina in the middle, a tiny bit of Escort at the bottom and on to a mini 2.2 turn steering rack, it's dynamite. The engine is run by a megasqirt (tho just running the coils, not injected since I took the blower off), a long time ago I made an electronic speedo drive - so steering is speed sensitive

[sambb]

Jesus I think I'd puke if I was a passenger in that thing. What a little weapon. Whats the go, did that have a spool did it? When it first turn in it did look like the inside front is rotating at a different speed but its not very clear. If so then yes, I vote Yes, weld your mini's diff.

Nice. My mate Pete in his Clio RS is changing from engine driven hydraulic to electro-hydraulic by fitting a holden Astra power steering pump. Its a common conversion because the controls for the pump are on the pump itself (like our ABS) you just need to power it up. I think it monitors fluid flow to vary assistance. Should be a good thing to watch take shape.

[Sydneykid]

Overthinking it again Sam, M12 bolt in a 13 mm hole is very common, as Simon posted achieving the recommended clamping force is the go. Centering should be achieved via the step in the diff centre that the crown wheel fits into.

The reason the rivets are used is commonly to allow for clearance to the oil scraper the fits/sits under the output shaft. You might want to check that there is enough clearance for the bolt heads.


Cheers
Gary

[Sydneykid]

Nice. My mate Pete in his Clio RS is changing from engine driven hydraulic to electro-hydraulic by fitting a holden Astra power steering pump. Its a common conversion because the controls for the pump are on the pump itself (like our ABS) you just need to power it up. I think it monitors fluid flow to vary assistance. Should be a good thing to watch take shape.

Astra electric power steering pumps are good (cheap too), we use them a lot. Mercedes ones are also good and a fair bit lighter, but obviously cost more.

Cheers
Gary

[Sydneykid]

more on diffs. I found this article (with links to other articles) about welded front diffs: Welded Differential In A Front Wheel Drive Track Car: Fast And Fun - Race & Track Driving (formerly Win HPDE)
Its pretty interesting actually. It got me thinking about what the lock up % actually are in the plate LSD compared to 100%/welded - is there actually any measure for that? The rallyanarchy links also almost exactly describe the short comings of the quaife atb's (virtually same as wavetrac) which I'd felt so I'm glad it wasn't all in my head.

There is only one advantage of a welded diff and that's cost. I have tried pretty much all types of diffs in 30+ years of racing FWD cars and the 1.5 way multiplate diff is my go to choice. Properly set up they provide more than sufficient locking on power application whilst also allowing some differential action on turn in whilst giving some limitations on inside wheel lock up under braking. The biggest problem I found with welded diffs in FWD cars is the sudden change of direction, when say someone has a lose in front of you, if you back off, brake and steer at the same time they will almost instantly spin, nonrecoverably. With a plate diff, it will unlock on back off and give you some chance of recovery, steering to avoid the accident or the armco.

Torson (ramp locking) style diffs are all just too slow, they allow too much wheelspin before locking.

We still run solid centre diffs (spools) in a lot of RWD cars, but I'm constantly tuning them to avoid the turn in understeer whilst not invoking even more corner exit oversteer. They work but it's hard work setting up the car around them. I'd much rather have a plate diff every time, makes my job easier. Yes, they cost more initially and have to be serviced, but easily worth the extra.


Cheers
Gary

[metalhead]

Andrew did you run with the Yoko's yet? Dam I really was hoping to get back up there before the hillclimb season shut down. Huntley is usually the last club hillclimb of the year so I'll see if they have another one. I wouldn't mind running back up that hill again to get a gauge on to what extent it was my FARB (now that I've softened the front off) or just the diff being maxxed out that caused the flighty handling there at that last state round.
Unforunately Pete seems pretty bent on doing the Supersprints based around Eastern Ck and Sydney. He's gone soft with all the state hillclimb travel already. The killer was the lotuses, Matt in the Skoda and particularly Graham Orr in the CRX dropping out all at once which left the <2.5L class empty. Unless Froedel is really developing his Clio (Pete had his measure) I don't think youll see us anywhere other than Bathurst, Ringwood, Huntley, and Canberra for the State rounds next year. I'll do South circuit at the DubNats next year, Wakefield and I'd like to do Ludenham too, so if I plan any of those I'll be in touch for sure.
Reckon you'd come down for a rallysprint? There's one in two days time but I wont be ready - cars good but I haven't entered, don't have a co-driver organised and dont have a leave pass.

No, haven't run the Yokos. I want to head down to a track day at Wakefield to get some track time in the car and finish off the AR-1s first anyway. I normally just run my street tyres on the car for the khanacrosses as they run more radical layouts and I can use the extra 0.5" ground clearance, not that it helped me avoid damaging the car on Saturday. But the AO50s are taller (295/35R18 instead of 295/30R18 ), so I may end up using them for the khanacrosses next year.

Huntley is done for the year too I believe, pretty sure their last event was on the 4th, same as the last Ringwood hillclimb.

Can't blame Pete for going for the supersprints instead. My brother won his class in the state supersprint championship this year in his mx5. I'd be considering it myself, but I want to see how I can do in the hillclimb championship this year first. Yeh, he'd definitely be quicker than Alex at this point, but Alex is looking at gradually developing his car to be quicker, and he can drive pretty well.

I'd definitely be keen for a rallysprint, I wanted to run one last year but it never quite worked out. I do really need to fix the diff (and the spoiler!) and a couple of other little things on the car first though. The gearbox is leaking - 2 year old brand new Tremec TKO600, not impressed... And the clutch is on the way out. Gotta replace the front sway bar bushes, and the shocks are getting a bit tired, been wondering about going with a stiffer front spring too - still running the original factory 1979 springs at the moment!

Nice. My mate Pete in his Clio RS is changing from engine driven hydraulic to electro-hydraulic by fitting a holden Astra power steering pump. Its a common conversion because the controls for the pump are on the pump itself (like our ABS) you just need to power it up. I think it monitors fluid flow to vary assistance. Should be a good thing to watch take shape.

That's neat, keep us updated on that. I'm hoping I've fixed my PS belt issue - I actually ran a few of the layouts on Saturday in first gear, so turned a few revs while turning and didn't have any problems.

[sambb]

Gary, what you said re the ring gear profile centering the diff just made something pretty critical occur to me. I'd been going on the assumption that I could just get someone to run through a 113mm ID crownwheel on the lathe and take it out to 114mm to match the LSD. But I rememebr now there is a chamfer on the the inside of the crownwheel that has to match the profile on the diff. So machining the smaller ID crown wheel to match the 114mm will probably be a more involved job than I'd anticipated.
I drop the box off on Wednesday to the gearbox guy so now its serious fingers crossed that I have the rarer (for an 02R) 114mm crown wheel.

[sambb]

Round 3 – Whiteline Twilight Tarmac Rally Sprint 2018/19-Members Only Events

This is the rallysprint I might be able to make. Dec 6th. After that I think they go quiet until round 4 in Feb. Andrew if you think you can make that let me know.
I noticed that Wakefield has 'open pit' track days, where you aren't locked into your group. Provided I don't have to be there at the driver briefing, It appeals because it means I don't have to be there at the crack of the sparrows and can drive down that morning and still get the track time I want. It could be that you're better off in groupings and open track will just lead to worse traffic issues than I had last time, but they are running it on dec 14th which is a Friday and may be a little more quiet. I might look at that but it is 70 bucks more expensive than normal.
And SMSP is running twilight track days run in the evening when daylight saving really kicks in, that could be cool too.