Are beefier parts available to us? Such as rear axles? I know theres a mugen LSD thats supposed to be stronger. I've e-mailed Darton to see if they make sleeves for our car, for possible forced induction. What Im basically asking is...Is there an effective way to lay lots of power to the ground w/out the risk of breaking something?

Johnny

 

There has been a lot of discussion about this type of thing and I almost wonder why? If you plan on dropping the clutch at 7000 rpm yes things are going to break because of the inertia of all the parts rotating at this rpm.
Now for some reason many people on this board believe that the drivetrain is weak for this reason. By having all the rotating components spin at 7000 rpm (vs 3000 rpm on say a normal drag launch) you have imparted a much greater inertia to the drivetrain.
Since some people have said that the drivetrain is weak they believe that with something like say the speedcraft turbo that the drivetrain will break. I believe that this is a completely incorrect assertion unless of course one continues with 7000 rpm clutch dumps. If one were to slip the clutch at say 3000 rpm I'm willing to bet the drivetrain would be much more durable (and since this turbo kit makes plenty of power at these rpm levels one would produce acceptable "drag launches")

To reiterate... the forces that one is exerting on the drivedrain with the power produced by the speedcraft turbo (for example) at a 3000 rpm launch is probably less than a 7000 rpm clutch dump with a stock s2k.

Also the amount of force you are exerting depends on how quickly you let the clutch out. By "slipping" a clutch you are allowing some of the energy from the rotating drivetrain to be converted to heat by allowing the clutch to slip ever so slightly. Here you are allowing time for the non moving parts of the drivetrain (i.e. wheels, driveshafts, lugs, etc) to be brought to the same speed as the moving components of the drivetrain. Of course with a clutch dump the clutch is not allowed time to slip and create some heat. Instead it grabs without slipping, but common sense (and sir issac newton) tells you the rest of the non-moving drivetrain will not instantaneously be brought to the same speed as the moving components. Instead the friction of the tires is overcome (thereby spinning them and dissapating energy as heat and sound) or by snapping driveshafts, lugs, etc.

Remember people on this board are dumping the clutch at 7000 rpm because the power curve of the engine is not suitable for slipping the clutch at 3000 rpm. If you modify that curve (ala speedcraft) a 7000 dump is no longer necessary. (Of course the superchargers are not suitable for slipping the clutch either so they wonder why drive components break when they drop the clutch at 7000 rpm.... not because the drivetrain is weakk.........)

So everyone flame away, Im sure no one believes this so only successful trials will prove my point......

 

[QUOTE]Originally posted by dre107
[B]Are beefier parts available to us?

 

Actually, you've made a very good point. So are you saying that replacing parts such as the LSD and the rear axles are not needed with the speedcraft turbo kit? I was under the impression that those parts in particular needed to be beefed up simply because of the additional 100-150 horses, not specifically for launching. Anyhow, you do make a very good point, and thanks for the imput.

Johnny

 

I'm pretty positive you wouldn't need anything extra with that kind of kit (especially with some of the claims that i have seen that claim we have the same rear end as the rx-7) I'm just saying that if you sit down and do the math (no guessing etc) that the amount of stress that one puts on the drivetrain by dumping the clutch is much much more than slipping the clutch at a lower rpm with a a turbo that adds more low end power (so you dont bog the launch)

I make no promises (especially if you go out buy the kit and decide to drop the clutch at seven grand) but the math and physics say that the stress put on the drivetrain should be lower than all those members who go out and drop their clutch and blame it on a "weak drivetrain" In fact i'd be willing to bet much stronger rear ends wouldn't hold up to that kind of stress.

I challenge anyone to show me the math and physics to prove me wrong.

The fact of the matter is that most of the "proof" here on the board about this matter is mere speculation (unsubstanstiated at that) and experience (mostly at dropping the clutch at 7000 rpm)
I have yet to hear from any turbocharged guys or supercharged guys say... "yeah my rear end disentigrated when I slipped the clutch at 3000 rpm"

But remember,even with a 3000 rpm slip you are still putting a significant load on the drivetrain just not as much as some of these guys who have had things catastrophically break on them.

 

QUOTE: Is there an effective way to lay lots of power to the ground w/out the risk of breaking something?

If you are asking this question then you aren't ready to "lay lots of power to the ground".

 

I mean lots of power as in forced induction. I dont exactly mean enormous amounts in excess of say...500 horses. A "300" to the ground would be nice, even nicer if the factory drivetrain could handle it, which from what has already been said, IS possible without 7k dumps. I basically want everything to be bulletproof at 300whp.

Johnny

 

With the speedcraft turbo, I don't believe no one does 7k drops. That is just too high of a rpm drop with that much power. ChrisD has the kit, and at the most, would drop it at 4500 to 5000 rpm. Mostly he would just slip the clutch at 3500 rpm. I believe the tranny would hold up no problem, but the axles and diff need to be replaced. No matter how careful you are, the diff will go out eventually.

I have heard the diff itself is not the main problem, but the actual casing and driveshaft. The case is fairly weak, and under drops, the driveshaft flexes and causes the case to flex, and you just got yourself a broken diff. My advice is to buy a comptech diff brace, and either get a KAZZ diff, or keep it stock, but definitely get the case cryoed. That would help a lot!

 

Actually the case doesn't support the pinion gear well enough and under high torque the pinion deflects and eats itself and the ring gear up. Picture the pinion moving inside the case and changing the contact pattern on the ring gear. That's why drag racers use the Ford 9" diff. Its pinion is supported at both ends. Three bearings total instead of two.

 

So where can I get a KAZZ diff at? at a good price of course. And a good price on the Comptech diff brace would be nice too. thanks fellas.

Johnny