Sam's build thread

[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.

[metalhead]

Hmmm... Maybe. I was looking at the Trackschool days of the 14th and 15th. I'll have to chuck the car up on the hoist and decide what it needs and whether I can get it done before then and/or the 6th. I'm keen, but not sure if I can make it work at this stage.

[sambb]

no worries. Keep it in mind and i'll get a few things squared away too so I'm ready to go if it looks likely.

[sambb]

found he this good vid (OS-Giken) that explains really well the inner workings and tuneability of clutch/plate LSD's. I know I can get different cone washers for mine and assume that I can adjust the locking % with the plate positions. Not sure about the springing preload on the inner ring ramps though. I assume my diff (as sold for a Golf Mk4) would already have had the cone washers and clutch orientations preselected for the application but its nice to know what is going on inside that casing.

YouTube

[metalhead]

Neat. I've been looking into the possibility of converting to a Ford 9" centre section in an irs housing, and one negative that surprised me was the lack of decent clutch LSD's available for a Ford 9". Heaps of locker and torsens style gear LSD's, but I really like the way the current tuned up clutch LSD works. OS Giken and Hollinger appear to be the only companies offering a decent aftermarket clutch LSD that would compare to my current diff. Apparently the design of the 9" limits the space available for clutch LSD's.

[sambb]

Is yours a Detroit locker now? Does the Eaton Posi fit yours?