2 Way a virgin's experience

[pepejesus]

madjak looked at some of the data last night and in one section of the track I was faster (in general) than on the lap I posted. Surprise, the turn in was a bit earlier and more speed was carried to the apex, hence faster exit speeds.

Lap looked pretty good and tidy everywhere, looks like you've got a fair bit left in the tank. If I could make one general suggestion it would be that you're turning in too late and squaring off the corners too much, and not carrying enough speed all the way through.

Turn in earlier, trail brake to rotate the car on entry, carry that entry speed all the way to the apex and then let that speed carry you right through to track out. I am worried that the 2-way won't let you rotate the car on entry as much as you might need, but then again I've never dríven an MX5 with a 2-way (only with a Torsen or an open diff) so I am admittedly talking out my arse.

With your driving style the 2-way will probably work quite well and be nice and consistent and predictable.

[Magpie]

pepejesus that is exactly what the data said. On the corners I took too deep (square) I carried less speed through the corner. Will post some screen shots. It is only by a bee's dick difference in distance between good and bad.

I used to turn in too early now too late Hopefully it will be just right soon... I'm learning slowly and yes I do listen to feedback!

[project.r.racing]

My Astina LSD had 8 clutch plates in it. Clutch plate LSDs sh!t on everything else.

As for 2 way LSDs. Probably not the best application for a small highly agile car. But I watched you video and I didn't see too many issues. The car handles the smaller slower final corners better that the earlier faster ones.

But like others have said, it is all a little bit of technique to get right. I'm seeing to go brake, reef hard on steering wheel and tail brakes (a lot) into corner. The 2 way is gonna go nuts on the arse end of the car doing that.

If you can up the rear bias a little to the point where the rear slides just a little, you'll get an easier entry turn. But you get into rally car would there, and isn't something everyone has the ability to do.

I'd probably keep it for a bit and trial a few things. slow in, fast out. double point braking, sliding car on entry.

[The American]

There's really no option now, but EFR and 450hp, in order to make the most of all that "flick it in, 'n' power out 2-way goodness

[Magpie]

project.r.racing thanks for the suggestions sound like most of the advice received to date. A rally driver I am not however did enjoy the dirt sprints maybe time to spend some more productive time there

Will see how it goes at QR in April then make some informed decisions then.

Not sure if this is the best place but looking at just one corner of Morgan Park at least 0.5 secs to be had between T4-T6. Blue was the fastest lap.

Part_01 by Eipeip, on Flickr

It would appear that for the purple line I braked too early and washed off too much speed. Whereas the red line was brake a little later.
Part_02 by Eipeip, on Flickr

Red line, carried more speed by turning in earlier, this is good...
Part_03 by Eipeip, on Flickr

However on exit the purple line has more speed and red is lower...
Part_04 by Eipeip, on Flickr

Purple is the fastest line and has picked up more time than the red line.
Part_05 by Eipeip, on Flickr

Part_06 by Eipeip, on Flickr


So, the members who said squaring the corner is wrong are correct, this is bad...
The red line, turning in earlier and braking later is much quicker. However the Purple line to exit is the fastest, this requires tightening up the turn at the apex and not drifting to the outside as far.

In by Eipeip, on Flickr

Out by Eipeip, on Flickr

[Ned Loh]

it appears that you had to get significantly off the throttle on the red trace which you didn't do on the purple. The purple exit speed may have nothing to do with line, but how you got onto the throttle.

in your post of 22/3, have a look at you driving at about 12-14s seconds in, and again at 30-34s. You stab the throttle, then get off it, then get back on it. If I recall corecctly you do the same thing on a number of other corners but couldn't be bothered watching the whole thing again. Watch the instructor, do they do that? or do they just squeeze power on smoothly. this will effect your exit speed! I think part of this is because you braked too much, but that is another story.

[Magpie]

Again thanks Ned Loh. Points noted about getting on the throttle, will try and work on it.

[project.r.racing]

Take the rear wing off and slip the mofo like you stole it.

[stuart1]

It all started with a comment about inside wheel unloading at QR on the sprint circuit. From this a chain of events Automotive Plus installed a 2 way diff into the MX5. This was NOT on the list of things to do in 2016, rather the plan was to make minimal changes and work on the driver. It should be noted before this my plan was working and times reflected this, finished 9th fastest in round 1 of QR Street Sprints, something never done before.

With the words of Captain Ramius echoing in my head "It reminds me of the heady days of Sputnik and Yuri Gagarin when the world trembled at the sound of our rockets. Now they will tremble again - at the sound of our silence. The order is: engage the silent drive" I approached the weekend at Morgan Park with all the confidence that every parent has that their child will grow up to be a doctor, astronaut or another Mother Teresa. How wrong I was....

After the first run on the Saturday I found out that a smoke screen maybe good for hiding from the enemy, but BAD on a race track. No need to go into the rest of the details they are public knowledge Anyway, made it back to the track for 2 runs on Layout E.

OMG, the car sucked BAD understeer everywhere, brake points all screwed up, nothing felt right. This was similar to attending Lakeside with an aggressive alignment that the car had never been set up with, very scary to drive! I persisted with the handling and just made it worse. In the end Saturday finished, car loaded onto the trailer, confidence shattered, ego destroyed and my sanity questioned.

After dinner with good company, where I was surprised to find a person that used more sarcasm than me, had a sleep ready for Sunday.

Arrived, unloaded the car and went about normal track things, checking oil/water/leaks and tyre pressures. Notice that the tyres were higher than their normal cold pressure. Adjusted accordingly, added 6 clicks to the front dampers.

Time to hit the track, damm that 2 way makes some chatter driving it slow is not fun... Took a completely different approach than on Saturday, went easy out and 'felt' what the car wanted to do. Came in adjusted pressures based on comments from SDT. Rinse repeat another 3 times.

Then onto Layout E. First session went at it like a bull in a china shop (mythbusters debunked) and the Saturday issues came back. Next session changed to early braking, no trail breaking get everything done in a straight line, nail the apex and then 100% throttle. OMG this is fun, only change was a PSI in the tyres and the drivers thinking. Everything started to fall into place, no fast laps yet, but so much more confidence. The big spin at T2 the exception.

Slug_dub jumped in for a few passenger laps at lunchtime and, like others, commented that I brake a lot earlier than he does, further I enter the corner slower BUT at the apex my exit speed is a lot faster.

After lunch started to push a little more, still everything in a straight line, BUT braking later (getting used to the VERY HIGH initial bite of the W6.5's). Even got to the point where could enter T1 in 4th and get the gear change to 3rd in before T2 (the cause of the big spin before lunch).

Whilst not setting the world on fire with my times, over 1 sec was chopped off my previous PB on Layout E. Looking at the logs I was never exceeding 1g of braking/cornering so this alone shows that a lot more time can be found!

What have I learnt about a 2 way from my first experience?
1. Can make any part of the corner under-steer
2. Requires a high level of skill in trail/threshold braking to get the most out of it due to the inherent under-steer the 2 way causes.
3. Under deceleration the car has a tendency to go straight ahead as the rear wheels resist the change in direction
4. Car resists turning under brakes
5. In a corner when the arse end starts to rotate turn the wheels where you want to go and nail it. This is not the fastest way around a corner but when you have stuffed up lap up makes for some fun

Final comment is from Keeley Motorsport who were out helping set up SDT's track cars, that was, a 1.5 way maybe more suitable.

Do I agree? Can't say as I'm still a 1.5 way virgin However, provided the brain is engaged I think the 2 way was a good move. Will find out on 10/04/16 at general practice and street sprints round 2

I was interested in seeing how you went with the 2-way Magpie.

Our car has a 1.5 way diff that initially worked extremely well.

Recently we replaced all the suspension bushes with poly units and at the same time changed the diff oil.

Next time out the car developed bad under-steer.

We worked on the front to try and cure this as there was another issue in the left front camber was changing and affecting the toe thus complicating the issue.

The camber issue turned out to be one of the bolts which had slightly less thread length and causing the nut to bottom out before enough pressure could be put on the excentric adjuster when everything was track hot.

That fixed, back to the track and still under-steer...At that point I was thinking the front tyres had gone off as the track temp was very hot at the time but no new tyres were available for another month.

Another track day and more bad under-steer.

This brought us back to the diff oil change...I could not get the recommended oil in AUS so used another that was advised to be OK.

By this time the diff was getting very clunky and noisy around the pits and sounding like a 2 way.

I have since got some recommended oil from Japan but have not yet installed it yet.

I am hoping that this may cure the under-steer problem that has crept in.

Knowing that you incurred under-steer with your 2 way gives me more conviction that our diff is now acting like a 2 way due possibly due to the oil currently in it.

I will let you know the outcome once we run the car again.

[Dan]

Why do you think the diff caused that and not the poly bushes?

You said the diff worked well, then you got poly bushes at the same time as you replaced the diff oil and understeer crept in.

Most likely your issue is in your suspension as you effectively increased your spring rates by fitting poly bushes.

My diff was ok initially with non-cusco oil, then the clunk crept in like yours and replacing it with Cusco oil fixed that but the performance of the diff on the track was the same.

Saying that it took a couple of tips from Daniel Deckers to get fast with the diff as I needed to change my driving style slightly to avoid the feeling of understeer.

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[Magpie]

It is more about the technique than a setup. As the LSD resists turning understeer will be more prevelant. It will take a few more track sessions to get the hang of it. The advice given so far of 'throwing' it into the corner will assist with breaking the rear grip enough to allow better turn in would appear to be logical.

Yes other things could be done to the setup to reduce the oversteer, but learning the nuances of the diff is more beneficial. Too often I have made the mistake of making too many changes, this time it will be get used to the diff before any other changes.

Hope this post has helped others, also thanks for the replies.

[plohl]

Why did you go a 2 way over a 1.5?

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[Magpie]

Circumstance