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Discussion Starter #1
I'm new to the CO forum and wanted to see if anybody was familiar with the URD crank pulley, and whether or not the claims of increased throttle response and HP as a result of reduced rotational mass are valid. It sounds good...but then part of me wants to think that there's a reason Toyota put a 10lb pulley on the crankshaft vs. something lighter (this being the V-6 on my '98 Taco)

Any insight on what the tradeoffs might be as far as switching to a lighter pulley? Any compromises in durability/reliability?

The issue driving me to consider this is that my crankshaft pulley/harmonic balancer has a pretty noticeable wobble....not terrible, but something that I want to have fixed. Here's the URD link:

http://www.urdusa.com/product_info.php?products_id=1230100021

Thanks for any feedback/opinions.
 

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im pretty sure the stock pulley is a larger dia than the urd pulley anyways. less rotational weight is easier on the supercharger though...
 

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Um no. The URD crankshaft pulley is a direct replacement (same diameter)...at least for the 3.4. I don't think that using this pulley would give significant results unless you've already got gobs of other goodies like S/C and fuel upgrades and you are trying to pinch every little bit of potential out of your engine. Maybe combine the lighter crankshaft pulley with an e-fan to eak out a little better MPG and throttle response, but your PEAK HP and TQ #'s shouldn't change at all with this pulley.
 

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Discussion Starter #4
I think you're confusing the supercharger pulley with the main crank pulley...2 separate things entirely. I do run the SC and will stick with the stock pulley...I've heard you don't want to step it down a size without doing the fuel upgrades and some fine tuning. And at this altitude, is it even necessary? I'm pretty happy with the improvement my SC gives me...especially doing the climb up I70 to the tunnel...now I pass just about everybody...
 

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What other mods do you currently have and are you getting any pinging? You can see my list of mods on my sig. Supposedly the stock pulley is 8lbs at sea level. Running the 2.2" URD pulley, I'm getting ~7.5lbs (Castle Rock is at 6200'). I spoke with a Toyota tech that says he sees the stock pulley pushing as little as 4lbs in the Denver area. He also told me he runs a 2.0" pulley at 8.5lbs w/o fuel mods and gets no pinging (one of the lucky few I guess). I get some detonation if I'm under ~2600rpm and a load up on the throttle. Currently, my solution is to stay in a lower gear until I've driven through the danger zone, but fuel upgrades are in the near future.
 

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Discussion Starter #6
Breathegood said:
What other mods do you currently have and are you getting any pinging? You can see my list of mods on my sig. Supposedly the stock pulley is 8lbs at sea level. Running the 2.2" URD pulley, I'm getting ~7.5lbs (Castle Rock is at 6200'). I spoke with a Toyota tech that says he sees the stock pulley pushing as little as 4lbs in the Denver area. He also told me he runs a 2.0" pulley at 8.5lbs w/o fuel mods and gets no pinging (one of the lucky few I guess). I get some detonation if I'm under ~2600rpm and a load up on the throttle. Currently, my solution is to stay in a lower gear until I've driven through the danger zone, but fuel upgrades are in the near future.
No mods other than the SC and a K&N FIPK. Thought about going back to the stock airbox & deck plate mod, but otherwise that's it. I had to get a new crank pulley since the stocker is wobbling. The URD crank pulley is a beautiful piece - too bad it has to be hidden way down in the engine compartment.

I may try a smaller diameter pulley on the SC, but have read that doing that necessitates the fuel delivery upgrades. Are you saying I could step down to a smaller SC pulley and be okay at this altitude with no fuel upgrades?

Like you, I need to remember to adjust my driving habits and keep the revs up above 3k to avoid that damn low RPM/tall gear ping. My mechanic said that the Toyota knock sensor doesn't really function below 2K RPM... :confused:
 

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There are a lot of guys running a smaller pulley in CO without fuel mods. Some experience pinging, some don't. We don't have the air density so the stock fuel system and computer can keep up a little easier than at sea level. That isn't to say that fuel upgrades aren't recomended, but if you are already in the habbit of driving around the ping, you could probably get by for a while......I have. Like my previous post states, the 2.2 got me back to about what the stock TRD pulley pushes at sea level. When I get my URD goodies installed, I'll probably step down to the 2.0" pulley.

I am really curious about the crankshaft pulley. It stands to reason that throttle response and excelleration might be improved, but I'm most curious about gas mileage. Keep us informed as to how it's working out for you after you put some miles on it.
 

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[rant] You guys are all scumbag pieces of shit. How DARE you worry about gas mileage on your supercharged 3.4's! It's probably STILL better than my 3.0, and you actually have power to boot! [/rant]

:D
 

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RedRunnertc said:
[rant] You guys are all scumbag pieces of shit. How DARE you worry about gas mileage on your supercharged 3.4's! It's probably STILL better than my 3.0, and you actually have power to boot! [/rant]

:D
A guy here where I work has a nice older 4runner like yours and did a 3.4 swap with 5speed. Nice armor, 33's, electric locker in the rear, maybe getting a crawler box soon.

Oh, and


 

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RedRunnertc said:
[rant] You guys are all scumbag pieces of shit. How DARE you worry about gas mileage on your supercharged 3.4's! It's probably STILL better than my 3.0, and you actually have power to boot! [/rant]

:D
Haha! What have you done to your 3.slo? My cousin has an early 90s regular cab long bed that he's tweeked into getting him between 25 and 30 mpg on the highway (stock tires & suspension). I know he didn't spend any $$$ accept on an aftermarket air filter.
 

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I have a 3.4L SC'd with all the URD upgrades and the smaller pulley. Most of the time i run flawless, but every now and again i get some of the pinging even up here in the mountains. I came from sea level, and had similar issues. My problems probably revolve around needing to fine tune my fuel settings. At sea level i was getting about 8.5psi boost.
 

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Since no one has answered your question yet... here we go.

I find these things (urd) are more "show pony" that "go pony" IME.

a lighter pulley might free up some resistance but you also lose momentum, you change the balance across the bottom end of the engine.

...you won't get much bang for the buck IME....it is one of those things that the sum of the whole is greater than the individual part ...so you end up rebuilding the whole bottom end to utilize the gains from a shiny lighter weight pulley...

if you read carefully the sales pitch states "to get the most of your RACE prepped engine"
 
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