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Discussion Starter · #1 ·
All,

I have been reading up on some of this stuff, but I wanted to get a discussion about it directly from you all in order to most probably learn a lot I haven't figured out yet.

Basically, what are the advantages/disadvantages between Mitsu's AWD approach, as opposed to Audi Quattro, Nissan's, Subaru's, Porsche's, etc.?

Just wondering you know, good knowledge to have (will the quattro car really be better in the snow over that GSX? etc.)

Thanx.
 

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I think the major advantages that the DSM all-wheel-drive driveline has over other major systems are:

1) Strength

People can bitch about the system not lasting very long once a car gets into the 10's or 9's, but put things in perspective! That's pretty damn strong for a stock factory AWD driveline that allows very little slip, thereby applying incredible pressure and stress on itself.

2) True Full Time All-Wheel-Drive

Many other manufacturers systems are based on a FWD or RWD trim of the same model, much like the GSX is based on the GS-T. Thing is, most of these "AWD" systems retain this configuration until slip is detected, then switch from FWD/RWD to AWD. IMO, this does not constitute a true all-wheel-drive system.

I posted this link to the Talon Digest in August of 99. It's very thorough and informative, discussing everything from the Ford Tempo to the Lamborghini Diablo VT, including the Eclipse GSX, with some nice diagrams linked as well. Very good read.

All Wheel Drive Systems

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1993 Forest Talon AWD - modified


[This message has been edited by ForestTalonAWD (edited October 23, 2000).]
 

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Discussion Starter · #3 ·
THanks for the info & link.

Cool, that is comforting news to know that virtually nobody with a GSX has ever cracked or broken their axle(s)/diffs/etc. unless they were running a 10 or 9 sec car!

However, axle boots need to be regularly checked upon. If the rubber rips, your screwed anyway, always check, AT LEAST twice a year.
 

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<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by ndahbar:
Cool, that is comforting news to know that virtually nobody with a GSX has ever cracked or broken their axle(s)/diffs/etc. unless they were running a 10 or 9 sec car!
<HR></BLOCKQUOTE>

I hope this was meant sarcastically ... either way, that's not what I was saying. People *have* been known to break axles (usually the 3-bolts), as well as differentials (usually the center diff). But even with these caveats, the DSM driveline outshines almost all other AWD systems available. the fact that people can have a daily driven 1G that whips off 11-second 1/4's with 1.6x 60-ft's every now and then should tell you something.


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1993 Forest Talon AWD - modified

[This message has been edited by ForestTalonAWD (edited October 23, 2000).]
 

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My friend busted an axle on his 14.3 second GSX. He just launched a little too high racing a Camaro. Snapped right by me. Very loud..

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John Lewis

1991 Eclipse GS Turbo

[This message has been edited by FastFWD (edited October 23, 2000).]
 

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Discussion Starter · #6 ·
Oooooow, he musta been PISSED.

Well, ACT3600 clutch or not, I'm through with very hard 1st gear AWD launches. The abuse is just not worth it if you're not trying to beat a time on the track or something.

Damn, I bet the Porsche Turbo's axles are bullet-proof to handle all that power (hell even Autothority's 600HP 993 doesn't have axle reinforcements I think).

Then again those cars cost 4-5 times the GSX. =)
 

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He was pissed. In fact, he traded his CRX for the Eclipse. He was so pissed that he called the guy and traded back. He always makes comments about how bad DSM suck and how they are trash. I just smile and say "Oh yeah? Wanna race?"

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John Lewis

1991 Eclipse GS Turbo
 

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Yeah I know! Honda owners claim how unreliable DSMs are... Well if your car only put down 100 hp to the front wheels, nothing is really being stressed. If you are consistently doing AWD launches with an ACT 2600, the stress it endures is incredible.


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1992 Eagle Talon TSI
13.8 @ 105.3 mph AT
Being Converted to 5-spd



 

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<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by FastFWD:
He was pissed. In fact, he traded his CRX for the Eclipse. He was so pissed that he called the guy and traded back. He always makes comments about how bad DSM suck and how they are trash. I just smile and say "Oh yeah? Wanna race?"<HR></BLOCKQUOTE>

See, that really sucks. :mad: The dude breaks one axle, which isn't a big deal, then just gets rid of the car. People puss out on DSM's when they don't get Honda-like reliability and actually have to keep up with maintenance and take car of a car. Neglecting maintenance and normal carcare usually causes more damage than actually beating on the car.

I'd rather break all 4 axles on my car and have to replace all of em than trade it for a f'in CRX. :D


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1993 Forest Talon AWD - modified
 

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I owned a CRX before my talon. You can see pictures of it at http://members.aol.com/shawncrx/crx/ . I sold it because the car was slow, and it would have taken thousands and thousands of dollars to be reasonably quick. I wanted a DSM for the last four years and I'm thrilled to finally have one. I would rather cut off my left nut than go back to that sled.

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Shawn B.
95 Talon TSi AWD
 

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******People *have* been known to break axles (usually the 3-bolts), as well as differentials (usually the center diff). ****

a good way around this is to weld the center diff. and go to a 4 bolt setup. this is almost an indestructible setup for an AWD under 350HP.

peace out
 

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To clarify: Our cars (AWD) are not true All time AWD. What happens is that they are 3 wheel drives, and then when the tranny sees that you are starting to over power the other 3 tires the Viscous coupling engages the last wheel. This happens so fast most of the time that you dont notice it. When you weld your center differential then it is true AWD all the time.

We had a team member of ours destroy is middle diff, rear axles, and vicous coupling. he was running 12.1's at 115mph and would not take our advice and weld the center diff.

Also Subaru's all wheel drive systems for their rally teams are better than say the EVO. Have you noticed that almost all the races are won by Subaru? Alot of the EVO's end the race with only RWD becuase they kill the AWD systems. Keep in mind that this is the race division.

Later

Richard www.thedsmshop.com
 

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<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by The DSM Shop:
To clarify: Our cars (AWD) are not true All time AWD. What happens is that they are 3 wheel drives, and then when the tranny sees that you are starting to over power the other 3 tires the Viscous coupling engages the last wheel. This happens so fast most of the time that you dont notice it. When you weld your center differential then it is true AWD all the time.

<HR></BLOCKQUOTE>

Can anyone verify this????????




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1993 Forest Talon AWD - modified
 

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Discussion Starter · #14 ·
3 wheels?

Richard,

Can you elaborate more? I don't get how in normal conditions engine torque is being distributed on the GSX. Now what I do know is that if we have both rear wheels and 1 of the front wheels slipping, we are screwed, unlike Audis w/Quattro cuz they need ALL 4 wheels to slip to become immobile.

So in saying that, both front wheels are driven with equal torque and then 1 wheel in the rear? Huh? Or does the rear diff do something I'm not aware of? Thanks
 

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During normal conditions, the AWD DSM's apply a 50/50 front-rear torque split. Moving down the highway, for instance, all four wheels are drive wheels. This is part of what makes the AWD models less-stellar performers from a rolling race than their FWD counterparts - the drag from the extra drive wheels, in addition to the extra weight.

Once slip is detected, torque is transferred to the wheels that have grip (AWAY from the slipping wheel(s)). Up to 100% (theoretically) can be applied to either the front or rear during a slip scenario.

For those equipped with a Limited-Slip Differential (LSD) in the rear, this allows the rear wheels to turn at different speeds to help elminate wheel spin.

I'd REALLY like to hear Richard/someone else elaborate on the "3 wheel drive" statement.

Also ...

"A system that can lock the center diff solid would also mean that each axle will have to be engineered to be able to handle 100% of the engine's output, when in reality it would be loaded no more than 50% most of the time. This would lead to a virtually indestructible system with a life that would far exceed the rest of the car. "

THIS is why people weld their center differentials, as well as to prevent the diff itself from breaking.
 

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Technically the 3 wheel drive statement is true for rear LSD equipped vehicles...

Unless a 4 wheel drive vehicle has LSD's then it is basically just a 2 wheel drive, if a 2 wheel drive vehicle has no LSD, then it's basically just a 1wd. Ever seen a muscle car without a Posi do a burnout? Usually just one wheel does all the work.

Since our Front Differential does not have any type of slip limiting mechanisms then whichever wheel is not being held can spin freely. Putting a FWD on a lift you can hold one tire with your hand and watch the other one spin at 2x the speed.

Once the viscous coupling(s) sense slip they basically just lock down on the other wheel. A Viscous coupling unit is basically just a friction/clutch pack with silicone fluid. Once the silicone fluid heats up due to slippage it locks the rotating assembly together.

Since the rear has a VCU (Viscous Coupling Unit) then it is considered a "two wheel drive" under slipping conditions.

The Center VCU locks the front diff and the rear diff together under slippage conditions, however, one front wheel can be held while the other three are transferring power.



Bill
92 GSX
http://www.dsetuning.com

ps...I've seen 16 second Hondas break axles with hard "launches"
 

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3 wheel drive

Lets make this simple. An AWD car with a rear LSD (limited slip diff). In the rear power is applied to both wheels because the rear uses the LSD. The front uses and open diff which only applies power to one wheel. Picture a FWD doing a pegleg burnout, only one wheel is being used. So, since both wheels in rear are being used and only one in front is being used, 2+1=3. Now if an AWD owner bought a front LSD then it would be able to use all four wheels during a slip situation. No factory AWDs came with LSD in both front and rear.

Later
 

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Discussion Starter · #19 ·
Quattro

Then how come Quattro-equipped Audis require all 4 wheels to slip in order to render the vehicle immobile? If they don't have front LSD of some sort?
 

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that's true of all AWD and 4WD vehicles...if all four wheels are slipping...then that must mean you're not moving...

Actually...what we mean by slipping is just a difference in tire speed...

Bill
92 GSX
 
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