Typical timing for street cars at Sepang SIC

[adian]

On a FWD car, having an LSD just means that you can put more power down without the front inside wheel spinning up. With the extra traction, the power can also be used to "pull" the car in line to the direction that you want to go. But as with everything else in life, too much power is not going to help you even if you have an LSD. You will still understeer.

With a FWD car ideally you want to be 'chucking' it into corners, get that rear around, and use the power transmitted through the front wheels to pull you in the direction you need to go.

If you've ever driven a RWD car in anger (or a go kart?), the quickest method is a 4-wheel drift (not drifting, that is different) where the steering wheel is almost straight but the car is going around the corner with the rear wheels doing the steering.

Similarly, you would want to achieve the same attitude with a FWD car. So getting the rear 'loose' on turn in, and then using the power smoothly and gently to then go around the turn, is the best way. No oversteer, no understeer. Just maximum cornering speed!

If you are understeering at T5 and T6, you really are simply being too rough with the throttle. Take it easy, find the balance point, and enjoy!!

/adian

 

[TitanRev]

Nice write up adian and loh.

 

[minivan]

What about turns T12 & T13?? Should turn 12 & 13 be taken almost similarly (like 5 and 6)?? I also use 4th for these corners. You also need to be gentle here, especially in 13 heading to 14 as you are braking in a corner (when you approach 14 for the back straight). If you're not careful there, you can also easily make the car spin... catching the car here i think is key...

Expert insight would be good. Adian bro... care to teach/give pointers ??

 

[cqloh]

what adian describes here is the car 'taking a set'..
that is the tyres adhering to the ground where the cornering forces on the front and the rear axle are equal.

in other words as you complete the initial braking and turning in process.. your car should take a set ...ideally your steering angle should remain unchanged up until you are ready to straighten up for the corner exit.. and your throttle should be maintained...no sudden jerks or adjustments..

for all you nerds out there its called 'steady state cornering'..

Bump: what adian describes here is the car 'taking a set'..
that is the tyres adhering to the ground where the cornering forces on the front and the rear axle are equal.

in other words as you complete the initial braking and turning in process.. your car should take a set ...ideally your steering angle should remain unchanged up until you are ready to straighten up for the corner exit.. and your throttle should be maintained...no sudden jerks or adjustments..

for all you nerds out there its called 'steady state cornering'..

 

[adam]

adian, 18th is afternoon or evening trackday? can join again? but need your pointers that day.. can? :)

 

[powersteer]

this is the best thread in ZTH

 

[soulV]

On a FWD car, having an LSD just means that you can put more power down without the front inside wheel spinning up. With the extra traction, the power can also be used to "pull" the car in line to the direction that you want to go. But as with everything else in life, too much power is not going to help you even if you have an LSD. You will still understeer.

With a FWD car ideally you want to be 'chucking' it into corners, get that rear around, and use the power transmitted through the front wheels to pull you in the direction you need to go.

If you've ever driven a RWD car in anger (or a go kart?), the quickest method is a 4-wheel drift (not drifting, that is different) where the steering wheel is almost straight but the car is going around the corner with the rear wheels doing the steering.

Similarly, you would want to achieve the same attitude with a FWD car. So getting the rear 'loose' on turn in, and then using the power smoothly and gently to then go around the turn, is the best way. No oversteer, no understeer. Just maximum cornering speed!


If you are understeering at T5 and T6, you really are simply being too rough with the throttle. Take it easy, find the balance point, and enjoy!!

/adian

i've just installed a spoon 1.5 lsd on my EF civiic & now trying to understand the car new cornering behaviour....what i've noticed that it is like the other way round of my previous type r lsd...during corners the car will understeer when i lift up the throttle n vice versa..any tips guys in handling this type of lsd?

 

[faisal]

just to update street car lap times. Did a drive a month back in SIC

Weekday open Track day, at 2 pm, on a dry track, drove a 2007 Civic Type-R (FD2) , stock std with speedcut still in place, set a best time of 2'45.5.

Car wasn't in the best of condition though, with dodgy gear linkage, causing up gear miss hifts into 2nd,3rd & 5th. And I was overdriving in certain sections

Believe a 2 43 would have been posible in better condition car. Coz that's exactly wat my friend did in a another Stock std Civic Type R (FD2)

Timed using a demontweeks lap timer.

Bump:

i've just installed a spoon 1.5 lsd on my EF civiic & now trying to understand the car new cornering behaviour....what i've noticed that it is like the other way round of my previous type r lsd...during corners the car will understeer when i lift up the throttle n vice versa..any tips guys in handling this type of lsd?

Do as Adian suggested in the 2nd paragraph of his post. You need to throttle to keep the car pointed towards the apex.

Basically u need to commit to the turn and power out.

 

[soulV]

thanks bro ...

 

[cqloh]

some may disagree on my views regarding LSDs... but i almost never install a 1.5way for my cars.. i say ALMOST...

1.5way lsds supposedly provide a 100% lock on throttle and 50% off throttle (i don't car what cusco and blah blah say... unless you are running a full spool.. they are only ideal figures for marketing!) lock at the wheels...

the problem is not when you're on the gas.. its when you're off the gas..
when you take your foot off the gas weight is transferred from your rear inside wheel onto your front outside wheel.. what this means is that your front outside tire is loaded more than the inside tire.. if your lsd is working.. it'll try to match the outside wheel speed to the inside wheel speed.. causing the tires to be overloaded.. hence the under steer...

the only situation that this is beneficial is when the car is on the limit of oversteer... by lifting off the throttle and letting physics do its job.. the front wheels will overload just as much as the rears and you get what the guys on TV call the four wheel drift.. utter rubbish again...
what you will get is an oversteering car that will very quicky become neutral... ie a controllable FWD car that oversteers.. perfect for the circuit...

however.. it'll have to be driven by a very skilled driver.. the main reason why i opt not to use them.

 

[soulV]

from what cqloh wrote especially the last sentence....i'm in a big trouble now...heheh..

thanks for the explaination but i need to clarify 1 more thing..my car when tekann minyak the car will pull inside corner n lepas minyak time the car will go straight(understeer) but some times it reacts the opposite ways(lepas minyak then car msk corner& vice versa) problem meh my lsd? and which one is the true character of an lsd?:rolleyes:

many thanks in advance

Bump: from what cqloh wrote especially the last sentence....i'm in a big trouble now...heheh..

thanks for the explaination but i need to clarify 1 more thing..my car when tekann minyak the car will pull inside corner n lepas minyak time the car will go straight(understeer) but some times it reacts the opposite ways(lepas minyak then car msk corner& vice versa) problem meh my lsd? and which one is the true character of an lsd?:rolleyes:

many thanks in advance

Bump: from what cqloh wrote especially the last sentence....i'm in a big trouble now...heheh..

thanks for the explaination but i need to clarify 1 more thing..my car when tekann minyak the car will pull inside corner n lepas minyak time the car will go straight(understeer) but some times it reacts the opposite ways(lepas minyak then car msk corner& vice versa) problem meh my lsd? and which one is the true character of an lsd?:rolleyes:

many thanks in advance

 

[minivan]

My 2 cents SoulV bro...

I think, the first one u mentioned (tekan minyak and feel a pull into the corner) is the 'lsd feel'...

The second one.... hmmm... i'm guessing that happens when ur overdriving it in certain situations. Like overcooking the throttle while in a fast corner will lead to understeer, irregardless u have lsd or not... so when this happens, lifting the throttle MAY bring it back in...

Dunno... sifu taiko can maybe help explain...

Bump: Owhh yeah.... another trick for understeer in a fwd car is left foot braking, while still maintaining throttle control.... i've tried it before with the desired results, but actually can't quite get the hang of it, as it requires a real steady left foot. Most of the time, i just mess it up...

 

[soulV]

thanks minivan.....
i am still trying to understand the character here....i've done both the test in <100kmh in 45degree corner so dont think the car should understeer yet...as minivan explain..it should be tekan minyak = pull in & lepas minyak no grip or the other way?

sorry slow learner here.......thanks

Bump: thanks minivan.....
i am still trying to understand the character here....i've done both the test in <100kmh in 45degree corner so dont think the car should understeer yet...as minivan explain..it should be tekan minyak = pull in & lepas minyak no grip or the other way?

sorry slow learner here.......thanks

i am just afraid that i ve installed a problem lsd here..

 

[adian]

SoulV... Being a 1.5way LSD, this is the expected reaction.

With LSDs, in essence the wheels will want to turn (golek) at the same speed, whether inside or outside wheel. When wheels at different corners turn at the same time, that means naturally, the car will want to go straight. Think about it before we go on... does that make sense to you?

When you are turning a corner, the inside wheel travels less distance than the outside wheel, yes? Draw two circles on a piece of paper, and measure the distance to travel around each circle. The other circle is a longer distance to go around than the inner one. That means the outer wheel travels faster than the inner wheel when your car takes a corner. So when both wheels are locked by an LSD (like a dead axle) they will want to turn at the same speed and hence want to go straight.

So, when you accelerate hard, the LSD engages and your car wants to drive straight, which is why you feel it understeers. WIth an LSD, you need to 'set' the car into the turn, and then gas it and hold on. But there is a balance point, where with just enough power (but not too much) the car will pull itself through the corner, very nicely. Too much power and you'll just understeer. In the wet, LSD FWD cars are a real handful! I used to have to fight the desire to floor the throttle through T5 and T6 in the wet when I used to race MSS many years ago, to make sure I dont under.

WIth the 1.5 way LSD, that means the LSD is working at 50% of it's torque/locking ratio on deceleration. That means that it's working even when you are braking or with your foot off the throttle. Which means that, you're going to have to pitch it in harder into a turn, and use the brakes very deliverately. Need more skill la basically. For beginners, 1way LSD is more appropriate.

/adian

 

[soulV]

thanks adian...i think i got a better pciture now on how does it work...it does feel good when i'm aiming for the corner but when i just went for a breeze morning drive to work it feels more diffficult to handle...maybe i've made a wrong dec in inslalling this at the 1st place....hmm...just drove the car for 2days after 6mths of driving auto persona car...huhu...i've used to drive this car using standard lsd before for 9 yrs (went to bt3 trackdayfew times with no prep at all..haha..really suicide that time) but i do think i need to study more n really understand & feel the car now since i feel just got a P license ...

anymore tips & experience to share with this new trackies wannabe...:wavey:

 

[cqloh]

soulV.. don't be disappointed with your decision having said all i have about the 1.5 way.

racing is about an entire package.. sometimes you make the right decisions.. sometimes you don't.. but instead of crying over something you probably don't have the resources to change (money, availability and more importantly time) you almost always have to live with it.

the philosophy behind building a race car (at least what i adopt) is to suit the car to the driver.. but we don't live in a world where everything goes your way.. so its a chance for you to suit your driving to the car.

since i'm not a driver like faisal or adian i can hardly explain the details in which you will experience with your setup ie. what line to take, when to brake and how much throttle to apply or remove...
what i can tell you from an engineering point of view is that with a 1.5 way (all other settings being the same camber, alignment, ride height etc) is that the car becomes sensitive in pitch.. that is the weight transfer for an aft of the car in a corner.. you need to balance the car with throttle and brake application; as i said above.. the amount of lock with the gas applied is the same.. it only happens when you are off the gas when the weight is transfered from the rear to the front..

when you get off the gas abruptly.. the weight is transfered quickly from the rear which overloads the front tires and causes the maximum LSD locking ability.. if you allow the weight to transfer in a smooth controlled manner the locking is reduced.
unless you know someone that has the experience and know how to set the preload on your LSD.. thats probably the best advice i can give you..

again it boils down to skill.. so practice practice practice..

 

[adian]

cq... nice. I am not an actual engineer so your explanation is a good one. I understand the basic intricacies of all these components, but not specific workings nor the physic behind them, so I very much appreciate and understand your write up. Thanks!

 

[soulV]

thanks cqloh for the write up...but then it trigger me to a new question...can the lsd preload be changed/set?for what?& the effect of changing the set up?

thanks again..

 

[cqloh]

adian.. hahah you're very welcome.. its always good when a driver appreciates an engineeres explanations.. they usually shrug and say "i just know how to drive"...

soulV.. LSD preload can be set on clutch type LSDs..well.. they also can be set for torsen and viscous.. but thats totally beyond our capabilities...
on the clutch type.. preload is set with springsthat push against the clutch packs of the lsd..
by changing preload.. you change the way the LSD bites... either abrupt or in linear fashion..

as with the example above.. if you reduced the preload in your lsd... you wouldn;t have to be gentle with the throttle control... the lsd would have done it for you by slowly loading up the tires.

 

[adian]

soulv/cqloh: yes, you can change the preload, but your 1.5 way setting is fixed, and that cant be changed unless you change to a different LSD casing! The best thing you can do right now SoulV is to get your LSD serviced and reduce the preload a bit as advised by Cq. That way it should be more progressive in relation to your driving.

Bump: soulv/cqloh: yes, you can change the preload, but your 1.5 way setting is fixed, and that cant be changed unless you change to a different LSD casing! The best thing you can do right now SoulV is to get your LSD serviced and reduce the preload a bit as advised by Cq. That way it should be more progressive in relation to your driving.