ACPT Carbon Fiber Driveshaft, Thread #2 - Page 4

**Nivek** · 10-09-2006, 11:07 AM

Quote:

Originally Posted by STIGUY88

I just got mine in a group buy. It shipped 10/2 and I received it 10/5. Do all the recent ones have the longer yolk? How can I tell for sure?

Furthermore, does anybody have a vibration "accelerating" through 110 mph? Cruising at that speed or reducing speed through that range, I am ok... but if I get on the gas I hear a vibration. Maybe it is the shaft hitting the brake cables or "grazing" the tunnel... hopefully installing some stiffer bushings will help?

You "hear a vibration?"

Please be more descriptive if you would like me to comment further.

IF it seems like it is rubbing, then I strongly recommend inspecting your driveshaft to make sure there are no serious issues. Shifter bushings will not help make something go away. Properly diagnosing is the first step to solving the problem. Right now, I need more information to be of any help.

PS: All new driveshafts have the yoke.

RacerXS · 10-09-2006, 12:10 PM

Quote:

Originally Posted by kwlsti

if that is true should i not get the drive shaft if i have a cusco trany/engin mounts and all the TiC bushings....? and how much viberation are we talking about, my street car is my race car, so it's not very street friendly all ready.

also how winter friendly is this, with all the salt i don't want to kill the drive shaft.

I have the Cusco engine & tranny mounts. When I first put the shaft in this was the only hardened mounts I had & there was some vibration issues, mostly when I would let off the throttle when I was past 4K + RPM's. It was nothing major, mostly annoying.
I then installed the TiC Outrigger, Rear diff, & cross member bushings and for good measure I also installed the Whiteline rear subframe locking bolts. The vibration from the shaft is gone. Definitely increased NVH, but SOOOO worth it. Those of you who have the "full monty" of bushings understand.
So, to summarize; I think the people with vibration issues that have the hardened Engine & tranny mounts have a very high likelyhood of solving their issues with the Outrigger, Rear diff, & cross member bushings at the expense of increased NVH.

AnorexicSTI · 10-09-2006, 12:47 PM

Quote:

Originally Posted by Nivek

You "hear a vibration?"

Please be more descriptive if you would like me to comment further.

IF it seems like it is rubbing, then I strongly recommend inspecting your driveshaft to make sure there are no serious issues. Shifter bushings will not help make something go away. Properly diagnosing is the first step to solving the problem. Right now, I need more information to be of any help.

PS: All new driveshafts have the yoke.

I feel AND hear a vibration that goes away after I get past that speed range. I think you made a typo when you said shifter. I said STIFFER bushings

- as in the outrigger bushings, stiffer tranny mount, etc. I think I remember reading somewhere in thread 1 that if you did ALL the mounts and bushings, that the vibration more or less went away (and you were left only with the extra NVH of the bushings/mounts themselves)... but if you did only SOME of them, it did not. --- AND just read the above post and feel like a tool.... that answers my question... I think I will get ALL the bushings and mounts.

Regarding the rubbing, why would it rub only at that speed and not the others?

Regarding the 4 hole attachment piece that goes to the rear diff - the bolts are squared off to allow them to "jam" up against a flat edge on the attachment piece so you can just tighten them with a 12 mm wrench. I found that on 2 of the holes, the flat edge was 2mm further away than it was supposed to be, and the bolt would just turn and turn and turn without jamming up against the flat surface. I then had to jam a flathead screwdriver in that gap so I could tighten the 12mm nut. Did you have this issue as well? For something in this price range, I would think ACPT would get something like this right.

subydoobydoo · 10-09-2006, 01:51 PM

Nivek, could you explain (or anyone) what you mean by the second half of this sentence? I don't understand what the Brake Man rotors mod is or how it helps? Does changing the rotors somehow help with power?

Sorry, I'm new to the game.

Quote:

Originally Posted by Nivek

Some say it is like going Cobb Stage 1 again while others attest that if it is done in conjunction with the Brake Man rotors, it is more like doing another Cobb Stage 2.

La Mer · 10-09-2006, 01:55 PM

Quote:

Originally Posted by subydoobydoo

Nivek, could you explain (or anyone) what you mean by the second half of this sentence? I don't understand what the Brake Man rotors mod is or how it helps? Does changing the rotors somehow help with power?

Sorry, I'm new to the game.

less "rotational mass". if it's lighter, it will spin "easier", and "quicker". not the most scientific explanation...

with the Brake Man rotors, you get lighter rotors to replace your OEM rotors.

**Nivek** · 10-09-2006, 02:24 PM

Exactly!

Take 20 pounds in a potato sack and swing it around. Your car must spin that extra 20 pounds to get the vehicle to move. Throttle response and handling are noticeably improved.

subydoobydoo · 10-09-2006, 02:42 PM

Oh, I was thinking that (that's what happens when you try to over think things). How much would I be looking to invest in this mod? How are they (brakeman rotors) compared to the stock? better stopping power? What's the weight difference? I never even thought about this. I was only going to change pads to get less dust and better stopping. But this opens up another avenue for me to take. Are there any other comparable rotors to these? What about the install? DIY or go to a shop? Man, do you guys know your sh*t!!

subydoobydoo · 10-09-2006, 03:24 PM

Never mind ^^. I did a search about these. PRICEY!

gohrsepwr · 10-09-2006, 05:34 PM

back to the subject, just when i thought i was done with mods i go and read this thread and im convinced i have to have the cf drive shaft. thanx...

TheLimitedProject · 10-09-2006, 07:10 PM

^^ I hear your pain.
After the dust settles on the mod spending blitz I've done, this is my next upgrade without a doubt.

Blaiser · 10-09-2006, 08:04 PM

has anyone dyno tested this yet?

DimitriosSTI · 10-09-2006, 11:29 PM

Quote:

Originally Posted by La Mer

did you read this thread at all?!?!

I know everyone is excited with this mod. I am expecting my driveshaft any day now and I am not sure what to expect. I am too excited myself I guess. Some reviews say it's effect is similar to the the TBE mod which for me is a big claim.

Prophet · 10-10-2006, 11:56 AM

I have been meaning to give some sort of review after I got my driveshaft installed but I have either been busy or lazy so I havent done it yet but now seems like a good time to do it.

The driveshaft seems to make the car happier. Clutch engagement is a lot smoother now which makes having this car as a daily driver that much more enjoyable. Also the jerky partial power at low speed is minimized.

There is also a decent amount of freed up power. I notice the freed up power mostly during highway driving the motor is more willing to rev and spin the turbo that it makes passing in 6th so much easier.

Butunfortunately I do have a couple issues.

This first one seems to have fixed its self but Im still going to mention it. Between 80 and 90 there was a slight vibration I felt through my seat but after driving it for a while the vibration went to 80-85 (noticed it mostly at around 83) and now it seems to be non existant.

This issue is still around though. During WOT acceleration during 1st and 2nd gear between 5k and 6k rpm there is a vibration. Its not a violent vibration and other people I have had ride with me had to pay attention to notice it. When I first drove it after the install the roads were still wet from rain so I thought it was probably a little wheel spin but having it be dry and this still happens I dont see that being the problem. The exhaust (atleast i believe its the exhaust) sounds different when I get this vibration also.

I havent been able to jack the car up to make sure clearances are still good but I know they were good after the driveshaft was installed. This has been my first mod so I dont have any harder mounts or bushings.

Hopefully my explanation is clear enough for someone to give me some ideas about what is happening (wrote this up at work so who knows how it came out...). If Im not clear I will try to reexplain.

My overall impression of this driveshaft is still positive.

krees23 · 10-10-2006, 03:12 PM

Quote:

Originally Posted by DimitriosSTI

did you guys notice any improvement performance wise?where is it most noticeable?low end?

I think I noticed the greatest difference in 5th and 6th. 1st through 4th went to redline fast with or without the driveshaft, so it's hard to really say for sure the difference there goes.

Rootus · 10-11-2006, 11:24 AM

Quote:

Originally Posted by Blaiser

has anyone dyno tested this yet?

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.

10-09-2006, 02:24 PM	#51
Nivek www.Subie.tv is niiice Posts: 10,068 Join Date: Aug 2003 Trader Rating: (10)	Exactly! Take 20 pounds in a potato sack and swing it around. Your car must spin that extra 20 pounds to get the vehicle to move. Throttle response and handling are noticeably improved.

10-09-2006, 02:42 PM	#52
subydoobydoo Junior STI Driver Car: 2006 WRB STI cobb st Fav Mod: Gruppe-s Coated Headers Location: Dutchess county NY Posts: 89 Join Date: Jul 2006 Trader Rating: (0)	Oh, I was thinking that (that's what happens when you try to over think things). How much would I be looking to invest in this mod? How are they (brakeman rotors) compared to the stock? better stopping power? What's the weight difference? I never even thought about this. I was only going to change pads to get less dust and better stopping. But this opens up another avenue for me to take. Are there any other comparable rotors to these? What about the install? DIY or go to a shop? Man, do you guys know your sh*t!!

10-09-2006, 03:24 PM	#53
subydoobydoo Junior STI Driver Car: 2006 WRB STI cobb st Fav Mod: Gruppe-s Coated Headers Location: Dutchess county NY Posts: 89 Join Date: Jul 2006 Trader Rating: (0)	Never mind ^^. I did a search about these. PRICEY!

10-09-2006, 05:34 PM	#54
gohrsepwr Senior STI Driver Car: 06 sti Fav Mod: invidia turbo back exhaust G200 Location: lexington, ky Posts: 370 Join Date: Jun 2006 Trader Rating: (9)	back to the subject, just when i thought i was done with mods i go and read this thread and im convinced i have to have the cf drive shaft. thanx...

10-09-2006, 07:10 PM	#55
TheLimitedProject Spec C Club Car: 07 STI LTD/08 STI Fav Mod: APS/Crawford/Cosworth/Aquamist Location: E-town, AB Posts: 2,337 Join Date: Apr 2005 Trader Rating: (5)	^^ I hear your pain. After the dust settles on the mod spending blitz I've done, this is my next upgrade without a doubt.

10-09-2006, 08:04 PM	#56
Blaiser Spec C Club Car: 06 white w/gold STi Fav Mod: gt40r Location: Orange, CA Posts: 1,226 Join Date: Apr 2005 Trader Rating: (6)	has anyone dyno tested this yet?

10-10-2006, 11:56 AM	#58
Prophet Junior STI Driver Car: 05 OBP STi Location: Waynesville, OH Posts: 90 Join Date: May 2006 Trader Rating: (0)	I have been meaning to give some sort of review after I got my driveshaft installed but I have either been busy or lazy so I havent done it yet but now seems like a good time to do it. The driveshaft seems to make the car happier. Clutch engagement is a lot smoother now which makes having this car as a daily driver that much more enjoyable. Also the jerky partial power at low speed is minimized. There is also a decent amount of freed up power. I notice the freed up power mostly during highway driving the motor is more willing to rev and spin the turbo that it makes passing in 6th so much easier. Butunfortunately I do have a couple issues. This first one seems to have fixed its self but Im still going to mention it. Between 80 and 90 there was a slight vibration I felt through my seat but after driving it for a while the vibration went to 80-85 (noticed it mostly at around 83) and now it seems to be non existant. This issue is still around though. During WOT acceleration during 1st and 2nd gear between 5k and 6k rpm there is a vibration. Its not a violent vibration and other people I have had ride with me had to pay attention to notice it. When I first drove it after the install the roads were still wet from rain so I thought it was probably a little wheel spin but having it be dry and this still happens I dont see that being the problem. The exhaust (atleast i believe its the exhaust) sounds different when I get this vibration also. I havent been able to jack the car up to make sure clearances are still good but I know they were good after the driveshaft was installed. This has been my first mod so I dont have any harder mounts or bushings. Hopefully my explanation is clear enough for someone to give me some ideas about what is happening (wrote this up at work so who knows how it came out...). If Im not clear I will try to reexplain. My overall impression of this driveshaft is still positive.