LSD in a NA?

[Neil Haughey]

Anyone on here have experience of what an NA is like on the track with an LSD fitted? The reason I ask is that even in the dry at Bedford this weekend I was getting the inside wheel (left) spinning up when changing from 2nd to 3rd gear after turn 1.

 

[Peter Empson]

I don't have experience of it on my car, but it's on my list of things to do before adding more power.

However I think it's worth bearing in mind that Bedford is a bit of an unusual track compared to most, after all it wasn't designed like other race circuits - its very unusual to get hairpins that are that severe anywhere else.

Saying that (and I admit I'm a bit rusty at the moment) but it sounds like you might still have had some lock on when you were going 2nd to 3rd. Might be worth trying to see if there's a different line that gets the car completely straight before going for the up change?

Just a thought[8|]

 

[Big Dave]

Yes a LSD in a NA is GREAT..
Ive got a Porsche plate diff, [out of a turbo] in my S2....It made a big difference...
Although youl find the car has a tendancy to understeer out of corners as your pushing the front wheels more , with better traction...
try giving PH sportscars a call.
I got mine from them + they had a few in stock ...

 

[Peter Empson]

Hi Dave,
I'm not quite ready to get one at the moment, but any idea what sort of cost they usually go for?
I've been looking a the Quaife one which is obviously dearer but I do prefer buying new mechanical parts wherever possible, so the piece of mind would seem nice.
Also did you take the oppurtunity to rebuild your box at the same time?
Best regards,
Peter

 

[Diver944]

ORIGINAL: Neil Haughey

changing from 2nd to 3rd gear after turn 1.

Surely that's a 3rd gear corner []

 

[Neil Haughey]

verry funny Diver944, the rest of the track is right in the power band for 3rd and 4th gear but thinking about it I would probably have gone faster if I could have down shifted to 2nd half way round the mega tight complex in the far corner. The car really bogged down coming out of that corner. I guess that when you tuck it in its about 40mph which is way out of the power band for 3rd gear in an S2. The weird problem was that the wheelspin after turn 1 was with the car straightened up, it was the left rear wheel and it only happened when being very aggresive with the gear shifts. My next upgrade though is to add more camber on the front and fit the 968 M030 front ARB. I was toying with fitting one of those last year but the track experienced confirmed to me that something which can help to get the front of the car down flatter will help no end. At the moment round those palmer curves the front roles a fair bit and the rear end squats like mad, still managing though in the dry to grab 4th prior to the right hand apex (85~90 mph). I also need to get to the bottom of why an M3 CSL can stand on the brakes after turn in to the first chicane whereas all the 944 need to start braking before the cone and trail brake much more gently.
It was fun though I am still buzzing now!

 

[Fen]

ORIGINAL: Neil Haughey

I also need to get to the bottom of why an M3 CSL can stand on the brakes after turn in to the first chicane whereas all the 944 need to start braking before the cone and trail brake much more gently.

Electronics? Circa 25 years extra suspension development?

 

[Neil Haughey]

This is exactly what I was thinking, maybe EBD linked in to some kind of stability program. I asked a quesiton on piston heads so it will be interesting to see what kind of response I get. I let the guy past and amazingly managed to hold the gap round the Beckam esses the straight and turn 1. He then got a big jump through the hairpin by said braking approach (and using all of the kerb area), and then pulled out perhaps 75% of the rest of the gap round the tight complex where as I said previously my car is in the wrong gear for perhaps 1/2 the time. I reckon he was about 2 to 3 seconds a lap quicker. About 3 laps latter my tyres balloned so I had to slow down and come in. The 944 also compared to other cars seems to perform much better in the high speed stuff, but with more camber on the front this area could be improved (will probably then really really need the LSD!)

 

[Fen]

Aside KW variant 3, which I can't recommend highly enough, and Weltmeister ARBs which make the 968 M030 ones look like the toys they are my car has adjustable top mounts. It is true that changing the camber has an effect on the toe, but not significantly enough to even accelerate tyre wear in my experience. With 3.5 degrees of negative my car was very planted at Oulton (the only dry day I got before it broke).

It also wears big blacks with awesome Performance Friction pads, yet on one particularly memorable corner entry I was braking what I considered quite late (albeit off line) and a 996 racer alongside me (who I had allowed the line) was still on WOT for what seemed like close to a full second after I hit the middle pedal before slowing like it had hit a wall and turning in with no drama whatsoever. By the next corner it was some number of car lengths ahead...

 

[Neil Haughey]

Yes the gt3rs is scary fast and that orange exige was blistering in the morning. I had a tricky moment when I pulled over to let the exige through only to see a white gt3rs nailed to its left hand rear quarter.

I fitted these BHP XPS pads mostly because I wanted something that would work OK on the road, remembering that my car is not a pure track machine (not for the moment anyways). So far I am massively impressed. I didn't get any fade, and personally I think I was braking very hard.

I love blue cars, me .....which is why I have one silver and one red.

What happened to "if it aint blown it sucks", just a question in passing?

 

[Fen]

Well the 964 isn't blown so it didn't seem totally appropriate any more. Technically it sucks of course. It was going to be blown, but I'm now thinking it's more likely it will be up for sale in 5 or 6 weeks as finacially it isn't worth taking it to New Zealand and I may as well try to sell it at the best time of year.

 

[sawood12]

Speaking of modern electronic aids and modern suspension it was nice to see that the cars that seemed to have the most off-track excursions at Bedford the most were Scooby's, Evo's and M3's. All this electronic gadgetry didn't seem to be that foolproof last saturday.

By the way, when it comes to camber is 2.5 degrees alot? The Racers Edge camber plates have a total adjustment of 2.5 degs so I was thinking about setting my road camber with the camber plates fully splayed out and sliding them fully inboard for the track to increase camber by 2.5 degs but I have no idea if that would be excessive or not - I don't want the car riding on the inside edge of the tyre.

By the way I didn't think that Quaiffe did an LSD for 944's, it seems to be a torque sensing one - which is even better in my opinion.

Unfortunately last time I was at PH Sportscars they didn't seem to have much in 944 parts, though I didn't ask about LSD gearboxes. They said smashed up 944's are getting hard to come by these days and they are getting alot more smashed up Boxsters instead. Shame - they used to be an absolute Aladins cave of parts, I used to drop by sometimes in my lunch hour just to have a browse at what they had in.

 

[lali]

ORIGINAL: Neil Haughey

Anyone on here have experience of what an NA is like on the track with an LSD fitted? The reason I ask is that even in the dry at Bedford this weekend I was getting the inside wheel (left) spinning up when changing from 2nd to 3rd gear after turn 1.

Is this still on the "west" circuit layout?
I agree with your later comment that its better as a 2nd gear corner but I only used to get the wheel spinning on one of the last corners on the GT circuit.... ( the right hander after the really tight hairpin )
Try a wider exit line... (the drain on the exit kurb should pass under the middle of the car) might help you get the power down.
I've got an LSD now so its all about understeer now.

 

[Fen]

ORIGINAL: sawood12

By the way, when it comes to camber is 2.5 degrees alot? The Racers Edge camber plates have a total adjustment of 2.5 degs so I was thinking about setting my road camber with the camber plates fully splayed out and sliding them fully inboard for the track to increase camber by 2.5 degs but I have no idea if that would be excessive or not - I don't want the car riding on the inside edge of the tyre.

That's what my Lindsey ones do; 2.5 degrees adjustment so I have the road setting at one end (of 1 degree negative) and then 3.5 degrees total on track with the adjustment the other way. Yes, that's a lot and the wheels look really "tipped in". You also need to set your toe for the road at one extreme to allow as much leeway as possible for the change caused by adjusting the camber.

 

[Big Dave]

Peter
In reply to your post.
I paid them £250 for a "unknown / untested "turbo box.
That was this time last year...
Yes i had it fully reconditioned.. LSD new plates ,new bearings , even had the cooler from the turbo box transfered over to the S2 box.. so ive got the best of all worlds.. low S2 gearing , LSD + cooling to boot...
BUT
I couldve bought a torson type diff for the amount of £££ I eventually spent.....[8|][8|][8|][8|].

Once fitted youve got to drive the car differently though..
With a plate diff it locks up in both acceleration + deceleration...So youve GOT to get the downshifts done right OR it WILL spin you round...Good for trail braking though.. Once youve mastered it...It does take time + patience though... And a few "red faced" episodes...[8|][][]
Also it can spin you if you apply the power too early coming out of some turns..Try powersliding at 80mph out of cascades at Oulton....A tad scary.... As more power is getting to the road.. Entertaining though....GREAT for drifting....[][][][][][][][][]

 

[333pg333]

With KW's and a decent brake system (pads, lines, ducts, fluid, calipers, rotors) you will find that you can brake much later without dive and squat. I have also put in the 928 proportioning valve 5/33 which is meant to change the attitude dramatically. I remember being amazed at how some modern cars just seemed to touch their brakes before getting right back on the loud pedal. The Cayman 'S' comes to mind. Once I changed to PFC's and KW's the gap closed considerably though. Power to weight isn't that much different, but the one Cayman 'S' in our club was quite a few seconds faster than us over the first part of last season. We started catching up, but with the carbon brakes and computerised everything, technology certainly shows.
As Dave says with his setup which sounds cheap enough you will get a marked improvement in your times once you acclimatise. You will not feel like you're in the wrong gear like we do with the standard gearing. I have done the S2 crown wheel and pinion change to my 951 'box and am putting in a Motorsport 80% lsd. This is all still on a road and track car too so don't worry that these are undriveable or anything. Get a ride with Dave or maybe he'll let you have a drive if you're really nice to him. [][][]

 

[Neil Haughey]

ORIGINAL: Fen

ORIGINAL: Neil Haughey

I also need to get to the bottom of why an M3 CSL can stand on the brakes after turn in to the first chicane whereas all the 944 need to start braking before the cone and trail brake much more gently.

Electronics? Circa 25 years extra suspension development?

Turns out that they have EBD and CBC (Corner Brake Control) which can't be disabled by turning off the DCSS thingy. Was certainly very impressive and of course has nothing to do with how quickly the car can stop. In the dry I was hitting 100 on the main straight and starting to brake at the marker or later which is very scary. I don't remember any cars braking quicker except when I was held up by traffic and yes the ABS cut in for perhaps 1/2 of the deceleration (225 wide Hankook RS tyres on the front, 968 ducts, BHP-XPS pads, blue fluid, SS lines, sebro x-drilled disks).

 

[Neil Haughey]

I believe that one of the reasons why me S2 worked so well at Bedford is due to the fact that for most of the circuit you are buzzing right in the power band for 3rd and 4th gear. Remember also that this is the speed range where the S2 is most impressive. 250 turbos with the much longer gears probably need somwhere with much longer straights to really wind up. As such the same ratios but mated to a much more powerful engine will go through the gears like a motorbike!

 

[Neil Haughey]

ORIGINAL: lali

ORIGINAL: Neil Haughey

Anyone on here have experience of what an NA is like on the track with an LSD fitted? The reason I ask is that even in the dry at Bedford this weekend I was getting the inside wheel (left) spinning up when changing from 2nd to 3rd gear after turn 1.

Is this still on the "west" circuit layout?
I agree with your later comment that its better as a 2nd gear corner but I only used to get the wheel spinning on one of the last corners on the GT circuit.... ( the right hander after the really tight hairpin )
Try a wider exit line... (the drain on the exit kurb should pass under the middle of the car) might help you get the power down.
I've got an LSD now so its all about understeer now.

Thanks, next time I do Bedford I will change the approach to complex completely. Accelerate in 3rd gear towards the marker half way round. Then a quick dab of brakes, heelNtoe into 2nd to tuck into the curbing on the last part of the corner. This should get me a much quicker exit and in the dry shouldn't give any wheelspin due to the slightly altered line making the exit straighter. On saturday I was tucking into the curbing on the last part using a slowly tightening arc/line whilst in 3rd gear, and no acceleration towards the marker half way round since I tended to aim to carry as much speed as possible through the right handed entry into the complex, and then let the corner scrub the speed off when turning left. It seemed 90+% of the ppl out there where taking the same approach but its probably not optimal.

 

[Hilux]

I believe that one of the reasons why me S2 worked so well at Bedford is due to the fact that for most of the circuit you are buzzing right in the power band for 3rd and 4th gear. Remember also that this is the speed range where the S2 is most impressive. 250 turbos with the much longer gears probably need somwhere with much longer straights to really wind up.

Yup

3rd gear all the way (4th v briefly) apart from the two twisty bends