Best 1/4 times EVER in a standard truck???!

oldsmokey97 said:
would there be any kind of way to get some kind of clutch disk to use in my truck with my 3850 pressure plate and the flywheel from my old FE assembly?? Something like a 4puck clutch that would hold some power and shift as fast as stock??
Cuz right now i am being held back by the times in between shifts with my DD and was wondering if I can mix-and-match parts to have a "like stock" shifting speed and still hold the power i got.

Lance
Click to expand...



Does anyone know if this setup is possible????

Also............. WHERE IS THE VIDS PEOPLE??

Lance
 
I'm shooting for low low 13's. I took a SRT-8 magnum to school with a 2 truck lead at 60mph before we shutdown. 2500rpm 2nd gear almost clutch drop launch shiftin up to into 5th. Once in 5th, the CR's start to move :)
 
I'm hoping for high 13's with mine, but expecting low 14's. I'm glad I didn't go dual disk now. There was a guy at the track recently with a CR running a dual disk and at least 100 more HP than mine and I could have beat him rather easily. I told my buddy my mission was to beat his best ever time at the track in his mustang, which was a 13.8, I fell I will be very close.
 
I have gone 13.33 at 98mph with just tuning, DD clutch, 4" exhaust, and K@N. :st: Hope to run in the 12s this year.
 
I clicked off a mid 16 second run with an Edge EZ on an 01 Dodge 6-speed. Nothing else.

I just installed my Haisley DD street drag this weekend, and now I'm itching to get back and go at it again..

I don't know where this rumor of a dual disk being slower to shift then a single disk came from. I can shift just as fast as my stocker, only now it hooks when I dump it hard. I'm betting I could easily drop into the low low 15s, might even break 14s now with the right (read: abusive) launch.
 
MD-LUCKY said:
I clicked off a mid 16 second run with an Edge EZ on an 01 Dodge 6-speed. Nothing else.

I just installed my Haisley DD street drag this weekend, and now I'm itching to get back and go at it again..

I don't know where this rumor of a dual disk being slower to shift then a single disk came from. I can shift just as fast as my stocker, only now it hooks when I dump it hard. I'm betting I could easily drop into the low low 15s, might even break 14s now with the right (read: abusive) launch.
Click to expand...



IT is not a rumor about the dd's being slower at shifting than a single. THEY ARE!! It just all depends on what kind of DD it is. It depends on plate load, Clutch disk weight and all the other stuff. A Drag racing DD shifts a lot faster than say something like an Iron GIant from SOuthbend.

Lance
 
oldsmokey97 said:
IT is not a rumor about the dd's being slower at shifting than a single. THEY ARE!! It just all depends on what kind of DD it is. It depends on plate load, Clutch disk weight and all the other stuff. A Drag racing DD shifts a lot faster than say something like an Iron GIant from SOuthbend.

Lance
Click to expand...

Well, If I'm wrong in my thinking here please explain to me why.. I'm not a clutch expert by any means, but I still think this isn't exactly correct:

The only reason a drag racing DD shifts faster then an iron giant is that you physically cannot release the clutch above 2k on some of these pulling clutches. Maybe its hydraulics, centrifugal force mixed with weight, plate load. To be honest, I don't know.. But it doesn't really matter. The issue is that the clutch won't release.

Assuming the clutch is going to release when you stab the pedal, there can't be any difference in how fast you shift, regardless of which clutch you use. The throw between gears is the same. Maybe the engagement point of the clutch is different between a single and dual disk, but if you are speed shifting that really wouldn't make a big difference. Since these transmissions are sychroed you don't need to double clutch or anything like that, so the input shaft should be spinning the exact same speed on a single disk as a dual disk. Weight of the clutch is irrelevant as far as I can tell: the transmission should only care about engine speed and input shaft speed for gearing.

I'm willing to bet a driver familiar with 2 clutches, 1 single and 1 dual, would shift almost exactly the same if you slowed the shift down and timed it by video.

But as I said before: I'm no clutch expert, and I can easily stand corrected. This post is a hypothetical question more then a statement at this point.
 
It is the plate load that makes them slow to shift. Longer for the disc to disengage all the way with a higher plate load. The Haisley Street Drag only has a 3000lbs plate load were he is running a 3850. The clutch he chose was more towards pulling sleds then drag racing. His will hold better in higher Hp but makes it slower to shift. I'm going to a 5speed from an auto and going to run a Haisley Street Drag. I heard rumurs Jeff Prince was very close to the 10 second mark with a stick.

Andy
 
Last edited:
You know, that kind of makes sense.. But I still don't totally buy it.

Isn't the clutch travel the exact same? Don't the hydraulics move the exact same distance? So even though the pedal pressure may increase, and the plate load may increase, the physical act of disengauging the clutch remains exactly the same. Doesn't it? So, assuming you can push the clutch in at the same speed, they should disengauge at the same point.. Right?
 
Technically yes it should but you can only move that plate so fast with hydraulics. The more preasure you put on one side of a hydraulic system the harder and slower it has to work. The clutch can not completely dissengage as fast as it did and when you try to speed shift you end up grinding. It's all about the laws in hydraulics. If you keep the same preasure to move a dual disc as a single that system has to compensate somewhere. You loose speed in the reaction times. From your foot to the preasure plate. Think of it as wieght lifting, you can lift 100lbs in a certain time frame. Now double that, you can still lift it but it will be a fraction slower in most cases. That is the only thing I can think of to explain it right now. That is also why the pedal gets harder, which also slows the speed at which you can depress the clutch pedal.

Andy
 
Okay.. But I still don't get it.

Your saying that the increased pressure causes the hydraulics to physically move slower?

I don't buy that either.. Your foot is moving at the same speed. The laws of hydraulics remain the exact same.. The fluid is compressing in the same way, there is no increased area for the fluid to move to instead of against the clutch.

For the hydraulics to move slower, the fluid would have to either compress more (don't buy that), fill a void where it couldn't go before (don't buy that either), or expand the lines out and create a larger area for the fluid to flow into (don't buy that, either).

The "engine" here in the hydraulic diagram is your leg, which has variable pressure available. Work is a measurement of speed. You are increasing work on your leg, but you are not decreasing speed.

In the weight lifter analogy, I lift 100lbs at 2 ft per second. You lift 200lbs at 2 ft per second. Which of us is lifting faster? You may expend more physical energy doing it, but the speed remains the same.
 
oldsmokey97 said:
IT is not a rumor about the dd's being slower at shifting than a single. THEY ARE!! It just all depends on what kind of DD it is. It depends on plate load, Clutch disk weight and all the other stuff. A Drag racing DD shifts a lot faster than say something like an Iron GIant from SOuthbend.

Lance
Click to expand...

How many times are you guys shifting in a pass? I start in third gear and I never hit sixth gear. Just two shifts for me.:woohoo:
 
Pat is itching to stuff a manual in Casper. Automatics are boring. :D
 
MD-LUCKY said:
Okay.. But I still don't get it.

Your saying that the increased pressure causes the hydraulics to physically move slower?

I don't buy that either.. Your foot is moving at the same speed. The laws of hydraulics remain the exact same.. The fluid is compressing in the same way, there is no increased area for the fluid to move to instead of against the clutch.

For the hydraulics to move slower, the fluid would have to either compress more (don't buy that), fill a void where it couldn't go before (don't buy that either), or expand the lines out and create a larger area for the fluid to flow into (don't buy that, either).

The "engine" here in the hydraulic diagram is your leg, which has variable pressure available. Work is a measurement of speed. You are increasing work on your leg, but you are not decreasing speed.

In the weight lifter analogy, I lift 100lbs at 2 ft per second. You lift 200lbs at 2 ft per second. Which of us is lifting faster? You may expend more physical energy doing it, but the speed remains the same.
Click to expand...


The hydraulic system can only move so much preasure at a given time. The system can only push so much preasure. When you upgrade to a larger dual disc you are pushing the limits of the hydraulics. The system can only produce so much preasure and the limiting factor is the plate load. At a certain point spring load starts to overcome hydrualic force. You increase the moving mass it will slow reaction times and cause more force to dissengage the disc. Yes your leg is the lever putting preasure on the clutch, and with the more preasure on the plate the slower it will be to react. I dont know how else to explain it. There is a limit on every hydraulic system of how fast and how much it will react. You are just pushing the system to the limit. Yes they do sell upgrade kits but they still dont help enough. Every hydraulic system is built with an internal bypass to keep preasures in check and you get to the point on some plate loads were the stock hydraulics cant keep up and the bypass.
 
What I understand is that with 2 clutch disks on the input shaft you have more rotating mass spinning. When you shift the synco's have more momentum to "slow down" as you shift to the next gear. That right there slows down the shifter.

As far as the clutch, if there's more plate load, you need a stronger leg to move it just as fast as one with a ligher plate load. The hydrolics will not slow things down, just provide the appropriate feed back (plate load).

For example

3000# plate
10PSI on the foot --> 100PSI on the plate to dis enguage

6000# plate

20psi on the foot --> 200psi on the plate to dis enguage

That right there will slow a human leg down.

SBC tells me that their DD clutch setups weight just a few #'s more then a Single disk setup. When you compare flywheel to pressure plate.

My next planned clutch will be a DD like the street drag I believe.
 
"As far as the clutch, if there's more plate load, you need a stronger leg to move it just as fast as one with a ligher plate load. The hydrolics will not slow things down, just provide the appropriate feed back (plate load)."

Thats exactly what I'm thinking.. But, if this is correct:

"Every hydraulic system is built with an internal bypass to keep preasures in check"


Then everything I'm basing it on is incorrect, and THAT is why a dual disk is slower to shift..

I can't really buy that the increase of another clutch disk is going to cause it to shift slower. The input shaft speed should be the same regardless of how many clutches are there. Here is an awsome animation of exactly what I'm talking about.. While the synchros may have to do more work, you should have no problem slamming the gear hard enough to go through the increased spinning mass (if there is any.. I'm not totally convinced there is to be honest..)

http://auto.howstuffworks.com/transmission3.htm
 
I dont know how else to explain it. You have more mass to move which takes longer to dissengage. Two clutch plates cant move as quick as one. Look at semis. The more moving items you put in there the more time it is going to take them to dissengage. I dont know how else to explain it.the more mass the slower and object becomes. It is not necisarily the weight but the mass of the clutches..
 
The point you are missing is that when you shift up, you are slowing the motor down.


Motor at 3200rpm, input shaft at 3200rpm = say 30mph.

You need to get 40mph, you need another gear. so you shift, in order to bring the RPM's back down to 2000rpm right. In order for the next gear to sync up the INPUT shaft speeds needs to MATCH the RPM that 3rd will require at 30mph. Motor RPM does not matter at this point since the clutch is dis engaged. how ever once you press the clutch in, the input shaft is at 3200rpm while in 2nd.

As you shift into 3rd you have to slow down the input shaft. That's what the syncro's are doing. They do nothing but speed up (down sift), or slow down (up shift) the input shaft. Once you add a second disk to that shaft, you effectively doubled the weight and mass it needs to manipulate.
 
I could sit here for hours and explain everything, but I won't and I'll try to keep it simple.

Hydraulics - fluids do not compress so there is no delay depending on plate pressure. If you can physically move your leg that fast, the pressure plate will release that fast unless it is a centrifugal assist type clutch, which I understand some pulling clutches are.

Syncro's - The job of a syncro is to slow the input shaft speed enought to match it to the output shaft speed. If there is more rotating mass on the input shaft it will make the syncro's job tougher. One could see it 2 different ways, the shift will either be slower due to the increased time it will take to match speeds or the syncro itself will wear out faster than normal due to the increased work it now needs to complete.

To summerize, depending on who is driving and what type of DD clutch one is using, the shift speed could be slower or could be the same as stock
 
Ken nailed my point down exactly.

And since most syncrhos use friction to match, its going to be nearly irrelevant in terms of how fast you can shift.

In other words. A the minimal amount of increased mass isn't going to stop the synchros from doing their job. More wear, maybe. But even that is a huge maybe.


To make the arguement that the increased mass of a second disk is going to prevent the synchros from doing their job in the same way is almost like saying that a clutch with 10,000 miles is going to shift slower then a clutch with 100,000 miles because at 10,000 miles there is more clutch material and more mass.

What would REALLY be interesting to me is to see the weight of a stock clutch, the weight of an after-market single, and the weight of after-market dual disk. I have access to a stocker with about 20,000 miles.. Maybe I will weigh it and report back. Anyone have a FE and dual disk to measure? The only difference is the clutch itself, so just weigh that.
 
You must log in or register to reply here.
Back
Top