View Full Version : ACPT Carbon Fiber Driveshaft Test


FLIWRX
02-26-2009, 12:24 PM
http://fliblog.files.wordpress.com/2009/02/_fli_acpt_main2.jpg?w=480&h=341

FLI has installed and sold ACPT carbon fiber driveshafts for Subaru STI’s for many years now. We wanted to take the time to write up an article about the ACPT carbon fiber driveshaft to show the improvements and advantages with a detailed customer testimony.

Our test was performed on James’ 2006 Subaru WRX Wagon with a 5 speed transmission. Modifications which complement the ACPT CF driveshaft are Tomei EQ header/up pipe, Cobb Tuning catted turbo back exhaust, VF39 STI turbo, APS FMIC, APS bov, Prodrive 3 port boost solenoid, , Whiteline ALK, Cobb Tuning front and rear sway bars, Prodrive lowering springs, Cobb Tuning short shifter with bushings, Cobb heat shield, Cobb lightweight pulley, Zero Sports intercooler splitter, STI US OEM oil cooler, Prova Oil Separator, Prodrive oil cap and a factory air box with a k & n panel air filter. The custom protuned map was made by FLI and saved on a Version 1 Cobb Tuning AccessPort.

http://fliblog.files.wordpress.com/2009/02/_fli_acpt_22.jpg?w=480&h=360

FLI tried to keep all factors the same in the dyno room. The before and after test was done with in 2 hours of each other on the same fuel and map. As you can see by the dyno graph, wheel torque was increased by 10-18 and wheel horsepower was around 10-12 pretty much throughout the power band! The base run was using the stock driveshaft with 55 degrees in the dyno room and 65% humidity and intake air temperature was 67 degrees. The test run was with the ACPT driveshaft and the dyno room was 57 degrees and 61% humidity with intake air temperature at 67 degrees. Max boost was around 15 psi tapering to 10 on both runs.

http://fliblog.files.wordpress.com/2009/02/dyno-acpt1.jpg?w=300&h=225

This is what James had to say about his new ACPT driveshaft:

Positive vibrations-
Driving out of the parking lot was a little shaky, but it smoothed out after 20 minutes on the road. The vibrations have moved……from before having a lot of vibration coming directly through the seat and some coming through the other touch points (steering wheel, shifter, pedals). Now, the seat feels more insulated, with less vibration on my spine/head. I attribute that to the removal of the center bearing. Initially, I did feel more vibration through the steering wheel and shifter, and a faint feeling like I was getting some vibrations from the rear diff. The new shaft definitely vibrates at a higher frequency, which causes less overall vibrations (harmonic vibrations) and doesn’t get the car singing like it used to. The car seems to have accepted the shaft and all is now quiet and smooth-like. This is a big plus in the wagon! It’s markedly quieter. Cruising at highway speed is so smooth and quiet, it sounds like a different car. I can hear the tires, the sweet purr of the motor, and the wind in the roof rack. Much better than the constant drone that I’ve been used to.

Faster?
Uh, hell yes. Other write-ups are correct. The car feels alive, the turbo seems to spool faster. Torque, once the turbo is at full boost, feels raw. It’s clear that more torque is getting to the ground. It’s night and day. Dyno showed 18 ft lbs at like 2700rpm, and it’s right when the turbo spools up, so I have to pay attention. I now have to be concerned about breaking all tires loose around slow, tight corners, it punches that hard. I would equate it to turning off your A/C four times over, or going from stock to stage 2. I was told by others that the car slows down faster also, and it does, but it’s only slightly and not a negative at all. I have the stock flywheel, I have no lurching issues in first at all. Drive ability has only improved. Highway speed acceleration in fifth is instant, which makes passing a breeze. I keep looking down to make sure I’m in fifth and not fourth.

Handling - I swear that the car’s suspension is plusher and more able to sink smoothly into corners. I notice smoother off/on transitions, especially throttling around corners. It feels like it’s letting the back of the car sink more, like there’s some benefit to not having the driveshaft fixed to the undercarriage at the center bearing. The rear end suspension just feels plugged in now and “looser.” It feels like I’ve got power more biased towards the rear.


Shift feel and rev-matching-
The shifter changes gear with confidence now. It’s the lazy up shift to third that usually catches me off guard, but I don’t think that’s going to happen any more. It’s like a three-finger affair (wait a minute!). Down shifting into second and first is markedly improved/possible. I also find myself using a wider range of RPMs now that bolt-loosening vibrations and noise are reduced. The car used to feel like it was coming unglued at 4000rpms, but now it’s pretty smooth all the way through, so I find myself driving in a better part of the power band, which of coarse is pure joy.

In summary, James says ” Don’t know what else to say besides I think it’s my favorite mod yet.”
James uses this WRX Wagon to it’s fullest potential. James is a hard core bicyclist, surfer and skier. With his bike racing background, James is in tune with his WRX wagon and all of the rotating parts in it.


FLI wants to thank James for his business and his words.

vodka
02-26-2009, 09:40 PM
+1 for ACPT CF Driveshafts, and +1 for FLI.

UP2MTNS
03-18-2009, 04:48 PM
damned....good write up.

now I want this, lol. well, maybe an AL one. :)

vodka
03-19-2009, 01:35 AM
Why go with a DSS aluminum DS, when the ACPT CF driveshaft doesn't require banging out the floor to fit? They're both good products, but if one fits as a bolt-on <30minute install, versus one requiring modification (read: hammering) of the car to fit, I'll take the bolt-on any day. :thumb:

HungrySTI4V8
03-22-2009, 08:24 PM
what happens if you launch your car can it break? wouldnt carbon be weaker than metal?

ciRe_oNe
03-22-2009, 08:47 PM
Carbon fiber offers you more strength to resist extreme torque than steel with about half the weight.

vodka
03-23-2009, 02:12 AM
Carbon fiber offers you more strength to resist extreme torque than steel with about half the weight.

QFT. No carbon fiber will not bend. A lightweight aluminum driveshaft is in fact (IIRC) far softer, and more likely to "warp" slowly over time with hard drag style launches. I thought it was some sort of "benefit" to them actually, for the drag guys. "Driveshaft takes a lot of the stress rather than the rest" sort of thing I thought, but I really only have personal experience with the ACPT CF piece.

bmxhotsauce
03-23-2009, 03:03 AM
how much for 1?

vodka
03-23-2009, 03:16 AM
how much for 1?

If you get in on a group buy, they're pretty decent, but I didn't at the time back in 2006. I paid like ~$1,100 for mine. Add on S&H and sales tax of course. One of my favorite mods, and I've done most everything including a full motor, so that is saying something. Well worth the money.

UP2MTNS
03-24-2009, 10:14 PM
Why go with a DSS aluminum DS, when the ACPT CF driveshaft doesn't require banging out the floor to fit? They're both good products, but if one fits as a bolt-on <30minute install, versus one requiring modification (read: hammering) of the car to fit, I'll take the bolt-on any day. :thumb:

this is why:

If you get in on a group buy, they're pretty decent, but I didn't at the time back in 2006. I paid like ~$1,100 for mine. Add on S&H and sales tax of course. One of my favorite mods, and I've done most everything including a full motor, so that is saying something. Well worth the money.

so, I'll bang on my floor a little bit if it saves me +$700 ;)

FLIWRX
03-26-2009, 11:24 AM
The reason we use the ACPT one on our part is due to ease of fitment. Its one of those things where we would prefer not to hammer out the underside of someones car if at all possible. On your car where it sees its fair share of abuse this might not be a problem for you at all. This is the conversation I can for see happening here at the shop.


Customer: Man Ryan I am so happy to get my drive shaft installed.

Ryan: Ya man you are really going to like it but we will have to make a small "modification" in order to make it fit.

Customer: What kind of modification?

Ryan: You see that hammer?

Customer: Yes

Ryan: We are going to bang the bottom of your car with it till it fits without any rubbing.

Customer: :confused:

Paul@dbtuned
03-26-2009, 12:02 PM
Quality costs money.

pwu_1
03-26-2009, 12:34 PM
so how much would it cost for installation? Is the installation something I can do myself without any specialized tools if I've done the turbo swap? Are there any possible long term reliability issues that one should be aware of? Would this mod cause even more stress on the (already weak early 02) transmission? I have an 02 wagon with a VF34 and supporting mods.
More torque to the ground sounds pretty good for the next mod but I'd want to know if I should be saving for a new gearset as well.

FLIWRX
03-26-2009, 12:55 PM
so how much would it cost for installation? Is the installation something I can do myself without any specialized tools if I've done the turbo swap? Are there any possible long term reliability issues that one should be aware of? Would this mod cause even more stress on the (already weak early 02) transmission? I have an 02 wagon with a VF34 and supporting mods.
More torque to the ground sounds pretty good for the next mod but I'd want to know if I should be saving for a new gearset as well.



It really depends on how many miles are on your tranny and how abusive you are in driving it. If you are not that abusive then adding the ACPT drive shaft would not be a problem. Now if you do drive the car hard and have a decent amount of miles on your car I would recommend a gear set now because of the drive shaft but just as a preemptive measure against your transmission braking. Plus with the shorter gearing of a RA gear set you will be able to accelerate quicker off the line. The drive shaft is easy enough for some one who is mechanically inclined to do on there own. We charge 170 to install it in case you were wondering.

Ryan

vodka
03-27-2009, 02:33 PM
Quality costs money.

QFT ^^^^^^^

Off Topic: This same principle also relates to strippers. You don't get the good ones without a lot of money.
/OT


The lightweight driveshaft upgrade is so underestimated by people. Everyone goes straight for the turbo, exhaust, fuel, FMIC upgrades etc, and overlooks a mod that won't get you any extra attention on the street, won't make your car louder, and doesn't make a "PSSSHHHHH" sound. I personally think the ACPT driveshaft is a solid part in any Stage 1 or 2 package.

pwu_1
03-29-2009, 12:23 AM
It really depends on how many miles are on your tranny and how abusive you are in driving it. If you are not that abusive then adding the ACPT drive shaft would not be a problem. Now if you do drive the car hard and have a decent amount of miles on your car I would recommend a gear set now because of the drive shaft but just as a preemptive measure against your transmission braking. Plus with the shorter gearing of a RA gear set you will be able to accelerate quicker off the line. The drive shaft is easy enough for some one who is mechanically inclined to do on there own. We charge 170 to install it in case you were wondering.

Ryan

my 02 has about 68K miles. I don't beat on the car too much, never taken it to the drag strip, no launching, just the occasional 3rd/4th gear pulls while getting on the freeway.
I think I lucked out and found someone selling a used one on nasioc. I should get it some time next week. Will report back on my thoughts after installing it.
I really hope it lives up to the hype.

pwu_1
04-03-2009, 10:49 PM
I just came back from a drive with the ACPT carbon fiber driveshaft. I must say I'm very happy with this mod. There is a definite gain in performance that can be felt by the butt dyno, but the reason why I like it so much is how it makes the car feel. Its hard to explain but basically it feels like you dropped a few hundred pounds off the car and it feels like the engine revs much easier now. The only thing that feels kind of weird to me is somehow the rear suspension feels different, like it can move more freely, or you can feel the weight transfer more. Its not bad, its just different.
Anway, I'm glad I read this review by FLI and found out about this mod. Even though it is pretty expensive, I think its totally worth it. If I ever get a STI, this will definitely be one of my first mods.

bmxhotsauce
04-03-2009, 11:01 PM
I just came back from a drive with the ACPT carbon fiber driveshaft. I must say I'm very happy with this mod. There is a definite gain in performance that can be felt by the butt dyno, but the reason why I like it so much is how it makes the car feel. Its hard to explain but basically it feels like you dropped a few hundred pounds off the car and it feels like the engine revs much easier now. The only thing that feels kind of weird to me is somehow the rear suspension feels different, like it can move more freely, or you can feel the weight transfer more. Its not bad, its just different.
Anway, I'm glad I read this review by FLI and found out about this mod. Even though it is pretty expensive, I think its totally worth it. If I ever get a STI, this will definitely be one of my first mods.

did it bolt rite up?? no modification needed??

pwu_1
04-04-2009, 06:41 PM
did it bolt rite up?? no modification needed??
Hardest part of the install was taking the mid-pipe off the kartboy exhaust hanger and breaking loose the bolts on the protection plate.
the driveshaft is 100% bolt-on. The only mod is you leave the protection plate off, otherwise it'll rub slightly. I've heard of some people putting in washers to lower the plate but I didn't bother putting the plate back.

ciRe_oNe
05-12-2009, 08:59 PM
I recently had this installed and I'm amazed at the difference in performance.

Low to mid pulls feel to be 50% improved. Car feels a lot smoother through revs and overall feels better.

No one talks about getting a carbon fiber drive shaft but ppl that own one can't stop talking about it.

John2.5RS
10-27-2009, 11:57 PM
I just picked up a CF driveshaft, looking forward to installing it; quick question.

what are the TQ specs of the Driveshaft-to-rear diff bolts?