Welcome to Ultimate Subaru Message Board, my lurker friend!
|Welcome to Ultimate Subaru Message Board, an unparalleled Subaru community full of the greatest Subaru gurus and modders on the planet! We offer technical information and discussion about all things Subaru, the best and most popular all wheel drive vehicles ever created.
We offer all this information for free to everyone, even lurkers like you! All we ask in return is that you sign up and give back some of what you get out - without our awesome registered users none of this would be possible! Plus, you get way more great stuff as a member! Lurk to lose, participate to WIN*!
* The joy of participation and being generally awesome constitutes winning
** Not an actual guarantee, but seriously, you probably won't regret it!
Serving the Subaru Community since May 18th, 1998!
UnOrthodox Underdrive Pulley Install
Posted 04 June 2001 - 10:43 PM
First thing I did was take out the radiator fans, not too hard. Next took the belts off, the pulley tensioners on these motors are quite ingenious. Then came the second biggest pain in the rump roast in the project. Loosening the bolt for the main pulley and getting it off. I had noone to help me, stuck a BIG screw driver down the little access hole on the auto tranny, and tried to hold the two while not poppin my shoulder out... I finally get the bolt off. Then the stupid pulley wouldn't come off. I bang on the inside of it with a small hammer for a while, finally got that off, after strugglin for a while. Cleaned the shaft, of course the stock pulley slides on and off alot easier now.
The biggest pain in the rump roast was getting the Underdrive pulley to fit. The key way did not fit. I'm pretty sure the main thing, was that it was not tall enough. I ended up filing the key way deeper, and slightly wider so it would fit on. I got it on almost all the way, maybe a mm or 2 that I didn't just push on with my hands. Then I just cranked it down the rest of the way with the bolt. The subie mechanic I talked to recommended 110 ft/lbs of torque on that bolt, as well as lock titing the threads. Reassembled in reverse order, the belts they sent fit perfectly. They were the gates Unorthodox recommended. I got my pulley from SPO Motorsports. They had probably one of the better prices.
Now you're probably askin, so was it worth the $190. Well I've put close to 1000 miles on it in the past few weeks, to and from school a bunch of times, and up to Toronto .
The biggest thing I notice is an increase in fuel economy. I have gone up 4-5 mpg on average, per tank of gas, even the way I drive . I went from around 20-21 mpg to 25-26 mpg or more, depending on type of driving conditions, and my lead foot. I would get 100 miles to half tank, I get 130+ Again big thing to remember is with my driving habits. It also feels more peppy, pretty much through entire rpm range. Other thing I've noticed is that it likes to drive faster....Like my car LOVES 90+ mph. The engine is in it's nice torque/hp range, 3000 rpm or more, and it seems to go faster, easier....uh oh...not good for me. HAHA.
Overall if I save 5-6 mpg per tank, I'll get my money's worth eventually, so it will have paid for itself. All and all, if you got the money, and it's burnin a hole in your pocket, and you don't know what to buy, this would make a nice addition If you have moderate mechanicing skills, you should be able to do this mod.
Now for the pictures
Posted 04 June 2001 - 11:32 PM
You have been such an asset to this forum, especially to me as I havent had my 90 Legacy a long time but have benefitted from your help more than a couple of times!
Might do that mod, if I ever find a job.
Posted 04 June 2001 - 11:56 PM
P.S. - Josh, you da man!
Posted 05 June 2001 - 05:04 AM
Did you buy that kit from Teague? Even if you didn't that is a heck of a plug for a product he sells.
Posted 05 June 2001 - 05:20 AM
Are you totally serious about the MPG gain? That's HUGE! I commute 400 miles per week, and a gain like that would pay for the pulley in just a few months.
(Note, it took un-lockable hubs, insulating the entire air intake, synthetic motor, gearbox, tranny and diff lube, and new driving habits to get our truck from 18 to 22 mpg, so I see a 1-part solution for 5+ mpg and get really interested...)
Question: Is the stock pulley considered a harmonic balancer in these cars? I know that in some vehicles such as BMWs, you don't want anything with less rotational weight to replace the stock pulley b/c it's designed to counteract rotational vibration (think twisted tuning fork) that otherwise tears the crank apart over time.
Has anyone seen whether the subee motors are OK with changes in the pulley weight? If they say it's Ok-- I think I'm going to have to play "follower" to this example...
Posted 05 June 2001 - 05:39 AM
my 2 cents,
Posted 05 June 2001 - 09:13 AM
Meep: Yeah I'm serious about the MPG. It may be on the higher side or lower side of what I said, depending on type of driving, and whether I feel like speedin or not...hehe. The only other thing I did was put in a new knock sensor around the same time. My old one was not bad, I just had fiddled with the wiring with Gary's hesitation fix, and didn't like the results so I put everything back. I didnt' feel like leavin the wires jimmy rigged, plus I heard the new knock sensors were better. I don't really know. I can't say I notice any difference in the area where the over sensitive knock sensor would cause hesitation. Plus I don't think that would change mpg that much.
The stock pulley is to my knowledge a harmonic balancer type thingy for the boxer engine. However it is no way like a harmonic balancer on a V-8 or something. As Huckster said the boxer engine's design is inherantly less vibration prone. So getting rid of the heavy stock pulley shouldn't be a problem. Mine really hasn't seemed to have any problems. Only thing I notice is that there is a slightly different tone or noise when idling. Almost like normal lifter noise, but just different tone or something. Idling may be the only area where it may not be perfectly smooth. Especially when fans are on. However my car never idled super smooth.
Other thing I didnt' mention is when I first used the A/C after I installed the pulley, the idle oscilated up and down a little bit, but then was fine after a while. I guess the computer relearned what it had to do to get the car to idle right with this pulley or what not. I don't have any problems with it now.
I don't want to make fabulous claims that everyone will see the mileage increase I did, but I am just reporting what I see and experience. I do think it is a good modification for the boxer engines, because they are more stable and have less vibrations.
If anyone has any more questions about the install, or pulley, etc. Don't hesitate to ask
Posted 05 June 2001 - 10:18 AM
97 Legacy GT
Posted 05 June 2001 - 10:27 AM
I guess now that you mentioned it, because the UOR pulley is alumnium it could use a little less torquing. I really don't know if 20 lbs of torque would do that though. I didn't have any problems with mine.
Posted 05 June 2001 - 11:19 AM
Thanks for the info. I read the SPO notes too, and for the most part they address the question of torsional dampening, etc., but they also caveat most of their statements in "does not use a harmonic balancer *in the traditional sense*". That still leaves the possibility of "untraditional" balancing-- so there's still a hole there; so I dropped them an e-m to see what they say.
Pretty interesting stuff-- actually, I suspect the ru's would have less of a problem than others b/c the crank is so short. It'd be a bigger problem in a straight six, or as y'all mentioned, in an 8.
Hey I'll let you know if SPO says anything interesting.
Y'all are great. This is a cool forum. Thanks for the opportunity to talk tech.
Posted 11 June 2001 - 05:41 PM
"Weight loss is the most critical factor in HP production, each lb. of mass taken off the crank/eccentric shaft is worth approximately 2.7 HP and the figure increases with forced induction, nitrous, VTEC and increased RPM's. Only 15-20% of the gains seen from our pulleys comes from the underdriving. We achieve the maximum gain for each application/model by the singular use or combination of reduced diameter ("underdriving") and weight loss versus the OEM crank pulley/s. This principle allows us to maximize the HP gain without causing any adverse effects in the general function of the vehicle."
As you can see, most of the gain comes from reduced weight, not from from the smaller diameter.
Some time back, I thought I read of a pulley which was a reduced weight version, but maintained the same diameter. (This would eliminate the new belts, concerns of dimming lights, etc.) Upon searching, I was unable to turn up such an animal.
I do a lot of "commuting". If I gained just a couple of mpg, I could pay for this thing inside of a year. Warrants a closer look... I'd like to hear of other people's experience.
Posted 11 June 2001 - 05:47 PM
Posted 13 June 2001 - 10:16 PM
Posted 14 June 2001 - 08:10 AM
Its kind of a pain in the rump roast to drill exactly oposite holes into the flywheel so that you do not offset the weight balance.
Posted 14 June 2001 - 08:45 AM
"The belt drive of the cams is sensitive to the rotational mass of the engine, so one ought to stay above 18 pounds to insure reliability. The WRC Prodrive rally cars do run light flywheel and clutch assemblies, but they modify the pulley arrangement and use a Kevlar ($$) belt."
I personally was unable to find a flywheel that wieghed more than 15 or 16 pounds if i remembercorrectly.
I was also wondering...I know that a lightened flywheel (i guess obviously) doesn't increase horsepower when measured at the crank, but what about horsepower at the wheels? I know it allows the engine to rev faster and increases acceleration times, and allows one to shift faster...
97 Legacy 2.5 GT
Posted 14 June 2001 - 08:57 AM
All the old gen buggers that have done it say they rev like a banshee and have more power through the whole power curve.
I have yet to hear anyone say theirs flew apart at 7k RPMs so as longas you dont take to much off your fine. I dont know the weight of these newer fly wheels. With the H6 Subaru noticed they had to drop some pounds off the flywheel to get some response out of the engine (the XT6's ER37 engine has a lighter fly wheel then the EA 82's; and I would bet the newer H6's have lighter flywheels then the EJ22 and other newer engines) So maybe the new H6's fly wheel would be an upgrade to other newer Subaru engines? SOmething to look into...
Posted 14 June 2001 - 10:12 AM
Posted 14 June 2001 - 10:45 AM
Well forget swaping flywheels!
Posted 14 July 2001 - 12:33 PM
Did the Unorthodox pulley have timing marks on it?
If not, does it even matter these days?
Posted 14 July 2001 - 06:47 PM
Posted 22 July 2001 - 10:12 AM
Posted 22 July 2001 - 12:57 PM
Also, looks like you bumped the thread.
Posted 22 July 2001 - 03:08 PM
Posted 22 July 2001 - 04:42 PM
No I really don't have any more dimming than I did before. I have an Optima deep cycle battery in though, so that could help. But for my car, no the lights don't dim any more then they did. Right now the most noticable thing is A/C sucks even more then it did before...hahaha....I need to get it recharged I think, at the very least.
0 user(s) are reading this topic
0 members, 0 guests, 0 anonymous users