[nhsilversti]

i should have my carup on a dyno on the 21st. a true before and after comparison, sort of. i will be on the same tune just a different day.

[SilverSurfer]

Originally Posted by La Mer

ACPT carbon fiber driveshaft, Thread #1

Here you go.

So does he mean that he made these gains going from bone stock to just the CF driveshaft or does he mean he made the gains going from bone stock to the CF driveshaft & a Cobb stg I???

"I have '05 STi, let me start off by saying I did read every page of this post and knew of all the issues that people were having with their driveshafts. I have like many others all the possible hardened bushings to be had except for the motor mounts. I left the D/S protection plate off to avoid any issues with rub because I don’t rally and don’t see the need for a few extra pounds anyway. I do have more vibes in the car with the shaft, but definitely see the improvements out weight the vibes. Anyway, yesterday I brought my old accelerometer performance computer to work for some after work data collection. This performance computer was one of the first available many years ago, I found it not the greatest at producing actual times the car was capable of, but more of what a specific mod or alteration would produce in the way of performance enhancement.
Okay, so if you follow me on that, given the data recorded yesterday and the data collected today with the exact same outside temp of 86* F. The data was a best of 3 runs average for ¼ mile and best 3 of 6 zero to 60 runs. Improvements were more than I expected, they were as follows:

0-60 mph improved by .39 seconds.

¼ mile time improved by .56 seconds.
¼ mile trap improved by 4.53 mph.

Now, keep in mind that my car ran a best on a 71* day of 13.32 @ 102.23 mph
This was when the car was bone stock.

Again, now with the car being Cobb Stage 1 map and the improvements of the data above with the Carbon Fiber D/S installed, I would think the car would be very capable of:

High 12s @ 105+ on a hot day like today, just think, .this will improve with TBE and Stage 2 mapping and then a protune. WooHoo!

The driveshaft will always be allowing more of the future mod power to the ground; you can’t go wrong with this mod my STI brothers.

The car was totally different from yesterday on the 90+ temp days to this mornings 67 degree start; the car could not be described as anything other than a raging bull. I actually surprised myself on a 4th to 3rd shift for a truck passing, the car was gone so friggen fast I spoke aloud words of joyful profanity."

[Nivek]

HSPN will be testing the ACPT driveshaft shortly:

http://hspn.tv/

Check out upcoming releases on the right side of that page below video channels.

[TheLimitedProject]

Thanks to this thread and the previous thread, as well as the reviews of the guys on here, my ACPT DS is ordered.
Josh @ ImportImage.com hooked me up. Can't wait for it's arrival

[RainMaker]

Man oh man. I went to www.importimage.com . NOT what I was looking for. 8-/

Im sorta with Dave (Rootus) on this one. The change in mass of the driveshaft is so close to the axis about which it spins... is so trivial that physics just doesnt seem to back up the claims.

Compare the moment of inertia to the brake rotors. You can replace our rotors and lose 20lbs (all 4 wheels) at a larger distance from the axis. AND thats weight loss that seriously benefits the suspension. OR get lighter wheels and tires...theres 4-5 lbs a corner there easily.

For the cost of this mod, there seems to be many better choices for your money, according to physical theory.

[Muffnbluff]

I just got my driveshaft installed and all I can say is the car friggin KICKS hard when you shift now. The 1st to 2nd shift at redline definitely puts you in your seat a lot lot harder. Plus I love how smooth the shifting is now, it feels like an automatic during those few shifts where I'm not slamming it into gear at 6k RPMs .

[nhsilversti]

Originally Posted by RainMaker

Man oh man. I went to www.importimage.com . NOT what I was looking for. 8-/

Im sorta with Dave (Rootus) on this one. The change in mass of the driveshaft is so close to the axis about which it spins... is so trivial that physics just doesnt seem to back up the claims.

Compare the moment of inertia to the brake rotors. You can replace our rotors and lose 20lbs (all 4 wheels) at a larger distance from the axis. AND thats weight loss that seriously benefits the suspension. OR get lighter wheels and tires...theres 4-5 lbs a corner there easily.

For the cost of this mod, there seems to be many better choices for your money, according to physical theory.

buy the ACPT DS and IF it does NOT do what we "claim" it does, I WILL BUY IT OFF YOU FOR EXACTLY WHAT YOU PAID INCLUDING SHIPPING. ah nevermind, sounds like you dont drive by the seat of your pants anyhow.

ted

[gohrsepwr]

Originally Posted by Rootus

I'd bet lunch a dyno test shows no difference. Changing the amount of rotating mass does not change the amount of power that actually gets to the ground, it simply reduces the amount of mass the engine has to accelerate. It would be like taking 50 pounds off the car and trying to measure that on a dyno . If you had a very, very heavy driveline, lightening it up significantly might change the dynosplot slightly by allowing torque increases to show slightly earlier. The amount of weight lost with a CF driveshaft is unlikely to show up as something identifiable.

hp is determind on how fast the engine can spin the drum (or w/e) up to max speed, the less time it takes to get there the more hp it is rated. less wieght to spin up= more hp.

[Nivek]

I am going down to ACPT tomorrow to meet James and hang out! I will tell him everyone here says hi and thanks for the hard work!!!

[Blaiser]

still no dyno test?

[rallymewrx]

will this fit a 2004 wrx?

[grim09]

Originally Posted by rallymewrx

will this fit a 2004 wrx?

no, the STi and the WRX have different driveshafts. ACPT will be releasing a driveshaft for the WRX very soon. You will be able to purchase it through sojdm.com.

[06stiman]

Originally Posted by Blaiser

still no dyno test?

I'm with Blaiser on this one. I really want to buy the driveshaft, but until I see some hard proof of the gains through a before/after dyno, I'm gonna have to keep my $1K in my pocket.

Come on, with as little time as everyone's claiming to swap the driveshaft, can't someone finally give us some dyno evidence?

[nhsilversti]

Originally Posted by 06stiman

I'm with Blaiser on this one. I really want to buy the driveshaft, but until I see some hard proof of the gains through a before/after dyno, I'm gonna have to keep my $1K in my pocket.

Come on, with as little time as everyone's claiming to swap the driveshaft, can't someone finally give us some dyno evidence?

now having the DS in and working i would have to say that even IF it showed NO gain on the dyno, it is still the best felt mod i have done.

ted

[grim09]

ACPT is working on it and will have a test done after the SEMA show. At the moment, everyone is busy trying to finish thier projects for the show. But i would have to agree with NHSILVERSTI on this, even if it didn't show any improvement on the car i have not found anything that has brought the car alive like the driveshaft did.