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#51 kikiturbo2

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Posted 07 February 2019 - 11:31

when you add 180 deg of steering in the middle of the corner and the car doesnt change direction, that is called terminal understeer.. :D



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#52 Fat Boy

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Posted 07 February 2019 - 21:35

That was my second or third time ever on a track. You where not even specific about anything.

 

https://youtu.be/dsOrDCeVXRo?t=98

Evaluate this then.

 

Can you see something strange about the handling of car? Surely you of all should be able to tell what is going on.. 

 

Get cheeky, that'll go a long way with me.

 

I would say a (not _the_, mind you) primary handling ill of the car is the complete disregard its driver has for anything resembling an apex.



#53 Kelpiecross

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Posted 08 February 2019 - 06:15

when you add 180 deg of steering in the middle of the corner and the car doesnt change direction, that is called terminal understeer.. :D


Terminal understeer is when you reach the full lock stop when cornering - which I have managed to do in a BMC Mini. Doesn't do the front tyres any good at all.

Edited by Kelpiecross, 08 February 2019 - 06:16.


#54 MatsNorway

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Posted 08 February 2019 - 17:44

Scandinavian flick?  :lol:  

 

As you wish. Same car, same track, same dude.. different tires. Notice the laptime and tires. There is also in the beginning at the second clip posted.

https://youtu.be/P0PH9oJyijs

 

There is something strange with the first timed clip i posted. That particular car in that clip/session/day.

 

More than one lap with the crap tires. I still have work to do when trying to set up a pass. I play it safe.

https://youtu.be/I5szeuEnStw?t=906

The "good" tires

https://youtu.be/tVG7ILBtd1o?t=492

 

 

 

primary handling ill of the car is the complete disregard its driver has for anything resembling an apex.

Weak. Are you not some kind of expert. Can you not tell what is wrong with it?


Edited by MatsNorway, 08 February 2019 - 18:46.


#55 Fat Boy

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Posted 09 February 2019 - 02:53

 

 

Weak. Are you not some kind of expert. Can you not tell what is wrong with it?

 

First and foremost, yes I am an expert. The car's fine. You drive like ****. There's too much wrong to hope to try to fix over the internet, but hitting the ****ing apex of the corners would be a good start ya mouthy ****.



#56 Kelpiecross

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Posted 09 February 2019 - 12:40


I'm an expert too - in fact I'm an expert at being an expert - but I am too modest to admit to it.

#57 NotAPineapple

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Posted 09 February 2019 - 14:46

https://youtu.be/dsOrDCeVXRo?t=98
Evaluate this then.

Can you see something strange about the handling of car? Surely you of all should be able to tell what is going on..


If I had to pick something related to the car it looks like it gets upset on the bumps on entry of the long right corner and that kills all your grip on both axles so you get the mix of os and us together.

Main problem though looks mainly to be you are approaching the corners way too fast and sawing hard at the wheel to get it to turn which is just saturating the front axle further and you go straight.

Edited by NotAPineapple, 09 February 2019 - 14:50.


#58 MatsNorway

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Posted 09 February 2019 - 14:51

Fat.. you so bad at this. And there was something wrong with that car. If you look at the other clips provided you should have been able to tell.

 

Reveal.

The front outer wheel rubbed just a little bit at the fender once you leaned on the front. causing more under steer.

You can tell by how i can go on the gas and sometimes get less/no more understeer than before in the left 90deg. corner after the tight hairpin.

I also think the large amount of thread pattern caused issues. My best tires have always been worn down, it feels like you can lean more on them then before the blocks give up.

Normally if i threw the cars into the corner i would get it to rotate and/or get oversteer. (which is fun!)

 

Like this:

Mitsubishi: https://youtu.be/P0PH9oJyijs

Toyota: https://youtu.be/9dQoB-3Lr0I

 

 

And when did any of you drive a bone stock open diff FWD car on a track with crappy tires with bad/wrong tyres that also had a understeer problem? With a manual, no side support in the seat and a steering wheel blocking your knee? Sometimes with different tyres front and rear.

 

And i do not go to the track to save the tires....

 

It is easy to look good in a good car.

I do not care what Fat says. He is filled with hate. When people come over to talk and excited because you are doing good lines or is keeping up with them/someone i am at least doing ok.

 

People ask me if i have done anything to it? and i say no, its a stock 1.3/1.6

 

I have done unmatched tires, new tires, worn tires, all season and winter tires on track in two different cars. It is a great learning experience and i always put the best tires at the rear to stay safe.


Edited by MatsNorway, 09 February 2019 - 17:18.


#59 MatsNorway

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Posted 09 February 2019 - 15:16

I presume that it is a front wheel drive car? It looked pretty good to me - very stable and predictable - as a FWD should be. Maybe a little more air in the front tyres?

Tyre pressure is something i always wonder about. How low i should go and so on. I want to monitor it as i drive in the future with the next car. Unless that is too expensive.



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#60 Bikr7549

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Posted 09 February 2019 - 17:20

Mats, those comments are way out of line. The forum rules may or may not be an issue here, but professionalism and common courtesy apply regardless. You asked for opinions and got a number of them, all in good faith. If you don't like them ignore them. Debate and lack of agreement are part of this and part of life, crudeness (in my opinion of course) has no place in a place like this. I've learned a lot from this thread, its been a really good one until these comments.

Bob



#61 MatsNorway

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Posted 09 February 2019 - 18:41

My apologies for derailing the thread.

Me and Fat boy have a history. I see him as a bit of bully and he has a short fuse, so he gets after other users far more than i have ever done. I have no problems with any other comments here (i probably agree to a degree) or the other forum members.


Edited by MatsNorway, 09 February 2019 - 19:17.


#62 Fat Boy

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Posted 09 February 2019 - 19:43

My apologies for derailing the thread.

Me and Fat boy have a history. I see him as a bit of bully and he has a short fuse, so he gets after other users far more than i have ever done. I have no problems with any other comments here (i probably agree to a degree) or the other forum members.

 

Short fuse? Incorrect. I've been quite patient with your stupidity.

 

I wrote, what, 4 pages of original content about a certain type of differential in this thread alone? Where else are you getting that information? Show it to me, because I don't see it anywhere. There's very little in the world I do correctly, but getting a car around a racetrack is one of them and I happen to like discussing the technical aspects of it with those who share the interest.

 

You go out of your way to talk about nonsense and derail some reasonably good technical information and I'm the 'bully'? Piss off. I'm just annoyed that you think it's your job to derail every bloody thread on this board.

 

Am I abrasive? Ya, maybe, but go to any professional paddock on the planet and you'll see I'm one of the most charming bastards around.



#63 Canuck

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Posted 10 February 2019 - 18:54

I’m pretty much always on the “asking” side of these conversations - it’s not often we hit a topic here where I can sit on the same side of the table as the professionals. Which is what they are. I’m grateful to have the opportunity to learn and ask questions and seek clarification and occasionally talk sh!t with them. It’s equally enlightening to see them disagree with each other.

Having said all that, it’s fair to say that I have not always appreciated the time and effort they put into answering, particularly when it’s not my question being addressed. Seeing the conversation derailed by an entirely off-topic tangent is surely frustrating at times, like interrupting someone trying to answer your question.

#64 Fat Boy

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Posted 11 February 2019 - 20:27

Canuck, I'm on the asking side just as often myself. As you can see in this thread, I started out incorrectly and had to go back and fix some of my errors. It's fun to kick ideas back and forth. Lee made the recommendation to bin the DL and just stick a spool in it's place. There's a damned good argument for doing this. If you have a rules package to get around, then it's a little less doable, but you can throw a super heavy spring in the thing and basically never have it unlock if you want. I think a well set up DL would be superior to the 'spool' conversion, but the spool would be better than a poorly set up or erratic DL. At the very least, spools are consistent and stable.

 

I've thought about putting together a thread on the subtlety of (plate style) differential changes. Honestly, it's amazing how _little_ difference in the diff on data makes for a meaningful difference behind the wheel.



#65 kikiturbo2

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Posted 12 February 2019 - 20:19

I am currently changing from a front torsen to a 1 way plate diff on a 4wd with active center and active rear diff... it will be interesting to see if it will make substantial change on a front heavy platform..



#66 Fat Boy

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Posted 17 February 2019 - 01:40

I am currently changing from a front torsen to a 1 way plate diff on a 4wd with active center and active rear diff... it will be interesting to see if it will make substantial change on a front heavy platform..

 

Honestly, I had to look up what a '1-way' diff is. It's what I'd call a ramp-style salisbury with 90 degree ramps on one side and something lesser than that on the other. That 90 degree ramp will provide no clamping force on the plates due to drive torque, so it has no locking function in that direction, in this case, coast. It will have some percentage of locking on the drive side which is dependent on the ramp angle. The torsen that kiki is presently running is a gear-type differential, which provides the same locking function in both directions (coast and drive). My guess would be that kiki is not happy with the locking of the front diff on corner entry.

 

It would follow that this should reduce tire scrub and understeer. If it were me, I'd keep these things in mind:

 

1.The locking that the torsen was providing on entry may have contributed to understeer, but it was also reducing locking of the inside front tire. I don't think that's an argument against your diff choice, but I do think I would have a small amount of preload <static locking> to provide the same benefit. (maybe 25 Nm to start?)

 

2. I'm sure if you have an open differential you have a problem of inside front wheelspin, so keeping that in check is a goal. I would have as little front diff. locking as I could get away with. The problem with too much front locking is that it helps in acceleration, but if you have the actually locked together and get front wheelspin, then front lateral grip goes to essentially zero. You could get in a 'snap push' condition, which is kinda a funny concept if you think about it. I'd have a minimum number of plates engaged and steep ramps (75-80 degrees).

 

I haven't played formally with AWD, but many years ago I had a Mazda 323 GTX which was an underrated little car. It had a turbo engine and AWD with a 35F/65R torque split. It was essentially a 'front assist' type arrangement. That car was fun as hell and would gladly provide tail-out slides *and* inside front wheelspin.



#67 kikiturbo2

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Posted 23 February 2019 - 21:40

FB, thanks for the technical insight.

You are right.. it is a salisbury with 90 deg ramp on the decel side. The diff in question came to me in a "tarmac" setup, witch is "1 way", i.e. no plate pressure on decel, but it does have about 180 Nm preload. I got some softer springs for it, but that will be 120 Nm.

I got this diff for free, and it is usually used on GrN rally versions of my car so I want to try it out. I expect more front end pull into the corner on lower speeds when on throttle as this is what I experienced on FWD cars.

Of course the "problem" is that I have to deal with 3 diffs, 2 of which are active, so it all is somehow connected... anyway it will be an interesting experiment.



#68 Magoo

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Posted 08 March 2019 - 01:56

Not that anyone asked, but the Detroit Locker was devised by Ray Thornton of the Thornton Tandem Company of Detroit, Michigan, an outfit that produced tandem-axle conversions for truck upfitters. Originally known as NoSpin, it was developed for the drive axles in six-wheel tandem trucks where it proved useful in WWII. The NoSpin business was spun off and eventually acquired by Eaton. As you were, carry on. 



#69 Lee Nicolle

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Posted 16 March 2019 - 22:47

I presume that it is a front wheel drive car? It looked pretty good to me - very stable and predictable - as a FWD should be. Maybe a little more air in the front tyres?

Front drivers are never stable or predictable. Bloody dangerous horrid things. Even for granny to take to the shops!!

Some are better sorted than others and can be basic family transport if never driven with any spirit. 

Cheap to build and sell many spare parts and service hours.

Pig understeer but with torque steer as well. What could go wrong!!

About the only front driver in regular use apart from crash filled one make series has been the BMC Mini. And they are bad but not diabolical unless they have an LSD. In the days I was racing at the pace of the best Minis it was easy to make them slow,, baulk them out of corners, BUT be prepared for a clout in the back. IF they get off the gas they go straight ahead. I once had one hit me that put him out. Crossflow and when he hit me it pushed the Uni filters down the carby throats!! And that car cost a lot more than mine.

In my rallycross days there was a few Minis and one very quick. But still stood on its nose over jumps and had serious ignition dramas with the water splash.



#70 Lee Nicolle

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Posted 16 March 2019 - 23:20

The trick is to give it more throttle when you get oversteer. :clap:

 

I actually have a video where you clearly can see the importance of correct gear and having some power ready to help you out in a sticky situation. First part is fourth gear, second is third.

Note: no servo, no ABS/assistance of any kind and no gloves and no support in seat at all so you have to support yourself by having the knee in the door++ Which is why it is so hard to downshift going into that corner.

If i had my knee straight when i initiate heel and toe i would hit the wheel with the knee.

https://www.youtube....h?v=-GocPUZPL4A

 

More serious: Would a Detroit locker be so bad tho? It is open on corner entry but would give a lot more mid to exit corner steering.

 

I guess the stabilizing effect from hitting the gas in a normal car is that the power is transferred to the inner wheel. Thus trying to rotate the mass in the opposite direction of the corner thus inducing understeer.

 

But by loading the outer front you nullify that effect, in turn you get only the extra rear grip from the stronger weight transfer. Not allways ideal. I guess it would be scarier in some situations on corner entry oversteer where you normally would throttle out of it.

Front driver. On road tyres. Pig understeer. Pump up front tyres 10lb, rears down to half, soften rear spring rate by half and stiffen the front. Stronger front sway bar and disconnect the rear. It will still do the same, just a little bit less. Some camber on all 4 wheels would help but make the car drive like a supermarket trolley in a straight line. And it is then a race car not a road car!

A road car front driver is designed for carrying passengers. This goes for all roadcars ofcourse. Rear tyres on front drivers are simply there to hold up the rear. But need springs double the ideal rate to carry passengers and luggage. Unlike a rear drive that need those spring rates to transmit the power to the wheels. And oh so may go stiffer in the rear. Which is dumb.

My Sports Sedan often used standard factory rate rear springs and that with soft slick tyres 3 times as wide with 3 times as much power. Though using a lot more sway bar. The car weighed 125kilo less than the factory car. 

The Improved Production cars I play with these days one uses standard base model springs and the other actually less than factory rate. Though factory springs were variable rate and the coilover springs I use are not. On both cars the front spring rate is a LOT harder. 300-400inch lbs stiffer. Or they simply fall over on the front tyre and wave the inside rear at the crowd. That with semi slicks and rims 2 inch wider.


Edited by Lee Nicolle, 16 March 2019 - 23:21.


#71 Fat Boy

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Posted 19 March 2019 - 17:02

Not that anyone asked, but the Detroit Locker was devised by Ray Thornton of the Thornton Tandem Company of Detroit, Michigan, an outfit that produced tandem-axle conversions for truck upfitters. Originally known as NoSpin, it was developed for the drive axles in six-wheel tandem trucks where it proved useful in WWII. The NoSpin business was spun off and eventually acquired by Eaton. As you were, carry on. 

 

 

I know you've got a fair bit of time playing with these things. Was there anything that you feel I got incorrect in my explanation?