How-To: Request: Driveshaft Replacement

[Batmobile_Engage]

You know how your head bobs back a little bit when you engage 2nd and 3rd gears at high rpms due to the G forces? I get that a bit more going into 5th now. Idk if that describes it.

Damn, it's tough to give butt dyno results.

 

[Spamby]

Thanks for taking the time with that. Gives me a good idea that the drivetrain will at least be less herky jerky.
Power gain is not my real goal but drive ability and response is more of what I'm after.
How about downshifts? I'm an avid downshifter and use the brakes more at the last minute. Does she feel like engine braking has been reduced at all? Significant or just some or none?

 

[Grinder34]

Dont forget, you're also taking a like...20 lbs of unsprung weight? I'm too lazy to look up weights right now, but it's substantial. That'll help with cornering. It's rotating weight which is a plus, and will help even more with acceleration. However, it's also very low in the car, so you will actually make the CG worse, but probably not by much.

Im a weight nazi, so this appeals very much to me, but less for the revving aspect, and more for lower overall weight.

 

[Batmobile_Engage]

Thanks for taking the time with that. Gives me a good idea that the drivetrain will at least be less herky jerky.
Power gain is not my real goal but drive ability and response is more of what I'm after.
How about downshifts? I'm an avid downshifter and use the brakes more at the last minute. Does she feel like engine braking has been reduced at all? Significant or just some or none?

Upshifts are definitely less jerky. I downshift a lot too. It seems smoother, but I haven't really paid attention to that much yet. I will now, just for you. lol It does seem to slow down faster while downshifting and braking.

Dont forget, you're also taking a like...20 lbs of unsprung weight? I'm too lazy to look up weights right now, but it's substantial. That'll help with cornering. It's rotating weight which is a plus, and will help even more with acceleration. However, it's also very low in the car, so you will actually make the CG worse, but probably not by much.

Im a weight nazi, so this appeals very much to me, but less for the revving aspect, and more for lower overall weight.

Stock = 24.9 lbs.
DSS CF = 12.2 lbs.

 

[Spamby]

Dont forget, you're also taking a like...20 lbs of unsprung weight? I'm too lazy to look up weights right now, but it's substantial. That'll help with cornering. It's rotating weight which is a plus, and will help even more with acceleration. However, it's also very low in the car, so you will actually make the CG worse, but probably not by much.

Im a weight nazi, so this appeals very much to me, but less for the revving aspect, and more for lower overall weight.

I hear ya. Maybe this will make up some for the big clunky wheels I have on.

 

[Spamby]

I will now, just for you. lol It does seem to slow down faster while downshifting and braking.

Odd. You would think compression braking would be less as in not as heavy and slower to slow down than before.



Stock = 24.9 lbs.
DSS CF = 12.2 lbs.

Nearly 13 lbs and 13 pounds is 13 pounds. Still a nice drop in weight in that area.

 

[Batmobile_Engage]

Odd. You would think compression braking would be less as in not as heavy and slower to slow down than before.

???
I never said that.

 

[Spamby]

It does seem to slow down faster while downshifting and braking.

^this is where I was coming from.
Less rotational weight would mean the engine would be slower to decelerate the car.
Perhaps I took it the wrong way?

 

[Batmobile_Engage]

I think it would be the other way around. The engine would slow the car quicker.

The engine has to slow not only the weight and inertia of the car, but also the wheels
and tires, axles, etc. etc. the driveshaft, etc. etc. connected to the engine. So a lighter
shaft should allow the engine to slow the car quicker because there is less drivetrain mass
to fight against.

Does that seem right?

 

[Spamby]

You just may be right. I think I am confusing engine rev decel vs. actual decel of vehicle.
Lighter components should cause a faster decel upon throttle lift with drivetrain coupled.
Engine rev should drop quickly with decel and uncoupled drivetrain.
I have confused myself, I think.
Throwing a tennis ball will accelerate faster but decelerate quicker.
Throwing a baseball will accelerate slower but decelerate slower.

 

[Batmobile_Engage]

Lighter components should cause a faster decel upon throttle lift with drivetrain coupled.

This is true. It does seem to allow for this. Though the effect is noticeable, I don't know how much of a quantitative effect it has.

 

[Batmobile_Engage]

This was such an easy install, there's hardly any point in making a How-To.

This video helps a lot to give you an idea of what you're getting into. I did not have to remove any of my exhaust to remove/install the driveshaft, though you may have to depending on your exhaust.

http://youtu.be/eKXLr3Rg1Cg