I have Quaife LSD installed in my Honda Prelude base and would like to share my impressions after about three autocross events. I have autocrossed my Prelude before the LSD install so can feel some difference.
I will not concentrate on straight acceleration as it is just too obvious - it is improved due to virtually eliminated front right wheel wheelspin.
Quaife LSD does not mean you'll never hear front wheel squeal again. There's a limit of torque this LSD can transfer from one wheel to another and the remainder of torque may still be enough to spin the inner front wheel in the turn. Also, it is necessary for one wheel to loose some traction (and squeal) in order for Quaife to feel that and transfer the torque to another wheel. But the squal in most cases is kind of different - sort of pulsing instead of permanent one. And the car will still accelerate pretty strong as _both_ wheels will do a good job pulling the car out of the turn. It is definitely not like before when inner wheel starts spinning and you instantly loose quite a bit of acceleration and lateral grip at once.
* Here's how I feel it was before the install:
You enter the turn, you start accelerating out of the turn and here's what happens:
- Inner (unloaded) wheel starts spinning. At this point it does not contribute much to either acceleration or lateral grip as it has no enough grip in either direction. This wheel is almost worthless.
- Outer (loaded) wheel does have the grip. But it does not contribute to Prelude's acceleration as all engine power is being spent on the inner wheel spin. It's lateral grip is pretty strong but it is just not enough one wheel's grip to take care of the heavy front wheel drive car's nose.
So the car goes wide under acceleration and one has to release the gas pedal back to the moment when the inner wheel catches up and stops spinning, gets some grip and this takes care of the issue by the price of poor corner exit performance.
* Here's what happens with LSD:
Inner wheel looses some traction but extra torque is being transferred to the outer wheel by LSD. The driver does not have to do anything with adjusting engine power due to the inner wheel loosing traction. The outer wheel makes the maximum use of it's extra traction working on both - acceleration and lateral grip, inner wheel is working on both - lateral grip and acceleration as much as it can as well. So the front axle is very-very smartly optimized for passing turns under the power and this improves car cornering big time.
So what does this mean for different types of turns?
Fast speed sweepers could be passed faster under more power now. More speed in these types of turns. You will even feel Quaife slightly pushing Prelude's nose inside the turn just like ATTS would do.
Slaloms - more speed under power and again - you feel like the nose is slightly moving toward the cones like ATTS would do.
Hairpins - it is possible to apply more power and accelerate earlier out of the turn and the front end of the car will be much more stable and going more where you point one rather than going too wide.
This distinct "ATTS effect" that I noticed allows to feel more relaxed in different types of turns and chicanes as it is more forgiving and takes care of slight mistakes of going into the turn slightly faster by allowing to stay tighter when exit the turn. You can now use power to help steer your car. That's very cool.
But in case you went into the turn way too fast... expect no easy recovery... you'll loose a lot of time
I feel like my Prelude has now redefined its limits and has more potential... So will have to work on myself to learn how to make it faster and release the potential. So maybe now those are not "slight mistakes of going into the turn slightly faster" , but one has to consistently dive in turns slightly faster than before
I am very happy with the LSD and do not think I'll ever want a FWD car without one.
Sounds good man, if I could go back to the time of my 5spd swap I would add an LSD to the to do list. I'll just have to wait till the engine or transmission dies on me.
Once I swapped my car with another guy's Prelude SH for autocross fun runs. I guess that was not enough to get the feeling of the system. Also, that Prelude was JRSC. I ended up having ATTS light on.
Oh, and I test drove several type SHs back in time when I was on the market for Prelude. But I guess I was not able to go wild enough at streets for ATTS to do some real job.
I bought a Base one. But that was based more on (used) car's condition than ATTS vs Base preference.
That was a very informative write-up. I haven't had a chance to drive a lude with an LSD yet but that write up was very descriptive. I have driven a new Civic Si with an LSD but the two are not really fair to compare, the civic is a high strung, twitchy, unrefined car whereas the lude is such a smooth, refined car at any speed. The Civic at anything over 100 became survival and was scary as hell and that's coming from someone who does track days, canyon runs, etc.
I totally experienced the pulsing locking feeling you were speaking of in the civic but I would bet that quaife makes a far nice LSD for the lude. By the way, what part of California are you located in?
Thank you. I was very hungry for this type of information back in time when was making my mind toward Quaife or any other type of LSD and was not able to find much. So wanted to share my experience.
I decided to go torsen type of LSD just because this should be relatively similar to what ATTS is doing but without extra weight penalty.
Quote:
Originally Posted by JHall250
the civic is a high strung, twitchy, unrefined car whereas the lude is such a smooth, refined car at any speed. The Civic at anything over 100 became survival and was scary as hell and that's coming from someone who does track days, canyon runs, etc.
Maybe that Mugen edition civic that has lots of airdynamic goodies alleviates high speed stability issues.
Quote:
Originally Posted by JHall250
By the way, what part of California are you located in?
It's not so much the specifications of the suspension, it's more to do with the chassis. The thing with the Civic Si/RSX, they are meant to be "sports cars" the prelude on the other hand is a touring car. Sports cars are as much about that "sporty" feeling as they are about actual performance. The Civic was designed and built to offer that sporty feel at everyday speeds of people who think they are sporty drivers. Touring cars on the other hand are meant to handle pretty well but be very comfortable and refined. So when it comes to the Civic, it doesn't really matter what you do to it, it's going to be a twitchy car.
When the 06 Civic Si came out my mom bought one and kept it for about a 1 and half. So I've have countless back to back comparisons up my sleeve starting from when my car was 100% stock and up until my current suspension setup. It's just not the same as a lude, it couldn't compare in just about every aspect. With just an exhaust, Tokico shocks with H&R Race springs, and the exact same tires my lude was dead even with that poor little Civic. With my current Koni/GC setup and Type S head/cams it absolutely stomped it in handling and would slightly walk it in straight line acceleration. 10 year old technology beating up on Honda's current premiere sports coupe; quite amusing. That's not to mention all the little stuff that bugged me about that car, RPM hang while shifting, worse Honda steering wheel to date, and of course the twitchy handling. It's not that I didn't like it but if we kept it there would be a bunch of things I would have to do to it to make it tolerable to drive whereas the Prelude I had the desire to change very little other than the overly soft suspension and slight underpowerment and even those things are bad, they're actually a sign of refinement.
That sucks that you live in San Fran otherwise I'd meet you at a track day or something.
I feel disappointed to almost everything Honda designed after year 2000 with some exceptions in Acura lineup (1st gen TSX). Back in 2000 even civic had double wishbones.
So I plan to stay with Prelude for a while now. At least until my kids fit in the rear . The only car I would buy instead of the Prelude would be IS300. I'd love to have S2000 but that's another story - I need more than 2 seats.
BMW3 is really good and I would even justify its high purchase price for myself, but I do not see reason for a car to be that expensive to maintain. And that's mostly reliability issues. Planned services I could swallow somehow. And if I just add AutoX to the list of its duties...
Prelude is not the fastest AutoX car, but I'm not the fastest driver
either . The point for me - it is fun to drive and it is refined.
And the car serves family car role for me (pretty unusual for most of
the ludes I think ) . It is not our primary family car for sure, but
I like being able to fit my family inside and have some spirited
driving over the weekend alltogether rather than scenario of having
S2000 staying in the garage.
So I afforded LSD in front to help myself releive rear wheel drive car desire
JHall250, I saw your Prelude's setup in another topic and see you have progr. sway bar at its stiffest setting. Do you use custom or OEM links?
I am using the Progress endlinks, if you have any change in ride height the stock end links will put preload on one side of the bar and then you have a very unhappy car. Darn good thing that Progress bar has that stiffest setting too because as you get the car stiffer the sway bar has less effect because there is body roll and therefore less suspension travel for any given situation.
The key to setting the rear sway bar is first installing it, then find a flat area and put your weight in crap on the drivers seat to simulate your body weight. Then, while the car is on the ground without a floor jack or anything, adjust the endlink you removed until it lines up perfectly level with the hole on the bar. This way you insure that you don't have the bar preloaded and that your handling will be balanced both ways.
There is some ignorant sh!t in this thread that I'd like to put to rest, so I'll just start with the dumbest:
"Honda's current premiere sports coupe"<- in reference to a civic.
WTF!?! You ever heard of the S2000? Give me a break. Civic, Honda's premier sports coupe? psssht.
And when comparing an LSD versus ATTS, understand that ATTS is not neccesarily meant to help traction, so much as it was designed to change the FF bias of the car. An LSD-equipped Prelude will take the hole shot against an ATTS lude, and probably beat it down the strip. But in a road course, especially in high-speed benders, ATTS will allow the car to point better through turns, which lightens the inherit "double-duty" that all FF setups find themselves shackled with.
I raced my SH with great success against a host of cars (front wheel, LSD FF, AWD and FR) without a problem. It's all in the driver. An LSD won't improve **** if you don't have a good line. Gotta have both.
__________________
Type-S Swap.
Last edited by what_the...; 10-16-2008 at 07:27 PM.
This thread compares Quaife, which is Torsen type LSD that does transfer torque between wheels with ATTS which transfers torque between wheels as well. While implementation details are different these two might serve pretty similar purpose in regards to FF bias correction. I drove both and I do see similarities as well as differences.
Also, you know the difference between coupe and roadster, right?
Now, if you have other opinion I beleive this could be expressed with argumants other than "sh!t, *****" and others. Otherwise it is pointless to continue.
Straight from Wikipedia:
"A coupé or coupe (from the French verb couper, to cut) is a closed car body style, the precise definition of which varies from manufacturer to manufacturer, and over time. Coupés are often hardtopped sports cars or sporty variants of sedan (also known as saloon — see American and British English spelling differences) body styles, with doors commonly reduced from 4 to 2, and a close-coupled interior (i.e. the rear seat placed further forward than in a standard sedan) offering either two seats or 2+2 seating (space for two passengers in the front and two occasional passengers or children in the rear). Before the days of motorized vehicles, the word referred to the front or after compartment of a Continental stagecoach."
Torsen LSD from Wikipedia:
"Torsen, (full name Torsen traction), is an automotive part, a limited slip differential. It was invented by American Vernon Gleasman[1] and manufactured by the Gleason Corporation.
Torsen is a contraction of Torque-Sensing.
TORSEN and TORSEN Traction are registered trademarks of JTEKT Torsen North America Inc (formerly Zexel Corporation, formerly Gleason Power Systems).
Torsen differentials can be utilised in one or more positions on a motor vehicle:
* centre - used to apportion appropriate torque distribution between front and rear axles on a four-wheel drive vehicle.
* rear - used to apportion appropriate torque distribution between left and right sides in rear axles. This may be on either a rear-wheel drive or four-wheel drive vehicle.
* front - used to apportion appropriate torque distribution between left and right sides in front axles. This may be on either a front-wheel drive or four-wheel drive vehicle."
Sounds very similar to ATTS to me. Anything else you would like to add?
Yeah, I'd like to add that ATTS is a torque senstive, or helical, limited slip differential. This is vastly different from a mechanical - which I believe the Quaife is - LSD that locks the two output shafts together.
Hence the turn-in behavior seen on ATTS equipped models.
I'm just saying they're different systems that try to solve the same problem. And since they're so different, they can be applied better in different scenarios.
Quaife has a great product, to be sure. But it's not the same as ATTS, and comparing the two is like comparing the transmission from a drag car to the transmission from a road car. Yes, they both make the car go faster, but they're clearly PURPOSE BUILT.
And the civic is not a sport coupe. It may, in fact, be a coupe since it has two doors and a roof (so does the smartfor2), but that doesn't make it a SPORT coupe as the original poster inferred.
__________________
Type-S Swap.
Last edited by what_the...; 10-16-2008 at 09:13 PM.
Yeah, I'd like to add that ATTS is a torque senstive, or helical, limited slip differential. This is vastly different from a mechanical - which I believe the Quaife is - LSD that locks the two output shafts together.
Ouch. Neither is correct.
Quaife is actually "a torque senstive, or helical, limited slip differential". ATTS is... well... there's a lot of reading on what ATTS is.
The actual ATTS unit has no idea what they hell is going on. There is a computer chip on the main ECU board that allows the completely separate ATTS computer to interface with the ECU. The ATTS control unit uses readings from a multitude of sensors
1) Steering angle sensors - installed on the steering column, this reports to the computer what position the steering wheel is in at any given time
2) Wheel speed sensors - The computer also receives readings from the wheel speed sensors the ABS system uses to ensure stability
3) Yaw rate/llateral G Sensor - Located in the front left portion of the trunk the yaw rate/lateral G sensor calculates the cornering force of the car and of the front and rear, also to keep the car stable in turns.
4) TPS - The throttle position sensor which communicates how much throttle is being applied
All these sensors report to the computer and/or ECU which all end up being processed by the ATTS computer at some point. After running the calculations the ATTS computer system sends the desired input to the ATTS unit which then adjusts the clutches depending on the situation. For the record there is no limited slip action at all in the ATTS unit, it's an electronically manipulated planetary differential (planetary meaning little gears the rotate around larger ones) it has nothing to do with Limited slips or limited slip technology. It purpose is to mimick the action of a Torsen LSD but do it in more accurate proactive fashion rather than a mechanically reactive fashion.
So a torsen LSD and ATTS are not similar systems in the realm of form but they are designed with the same target function in mind and go about in ways that, though different, end up producing similar results which is the entire reason for the post in the first place; to state the review of a Torsen LSD and compare it to ATTS.
As for the Civic Si not being sports coupe, you must be joking.
From Yahoo Autos
"The 2009 Civic Si Coupe is a 2-door, 5-passenger sports coupe, available in 4 trims, ranging from the 6-Spd MT to the 6-Spd MT w/ Nav and Performance Tires."
From Edmund's Full Test of the 06 Civic Si
"Honda's designers wanted the Civic's interior to look "futuristic and sophisticated," and it works on us. Subtle touches like the sculpted steering wheel hub and the gentle slopes of the dash appeal to our artistic side, while simple controls, ergonomically shaped door armrests and the vast amount of storage slots provide more day-to-day practicality than we thought possible in a budget sport coupe."
You know something, that phrase sport coupe just keeps reappearing.
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