URD Pulley question

[3rdgenfan]

I am looking at buying the pulley upgrade for my 4runner. I do not have any supporting fuel mods yet. From what I understand is the 2.2" pulley is best used for daily driving. The 2.1" is used for high elevation. I do live in colorado springs which averages around 6,300ft. Where I go do some off-roading goes all the way up to 9000-10,000 ft.

I always thought with a supercharger a smaller pulley gives you more power. Should I just run the 2.2 pulley with no other supporting fuel mods? I don't want to get the 2.1 and take the chance of messing up my engine. Thinking about getting an A/F gauge as well. Anyone at high elevation please chime in and let me know what you are running.

 

[A.Wilson013]

Should I just run the 2.2 pulley with no other supporting fuel mods?

If I were to make a list of things you should do, that would be no where on it.

I highly discourage you running a smaller pulley without any fuel mods, and especially without a wideband AF gauge.

 

[3rdgenfan]

If I were to make a list of things you should do, that would be no where on it.

I highly discourage you running a smaller pulley without any fuel mods, and especially without a wideband AF gauge.

So i should hold off until I decide to pick up the 7th injector kit?

 

[shootmymime]

If I were to make a list of things you should do, that would be no where on it.

I highly discourage you running a smaller pulley without any fuel mods, and especially without a wideband AF gauge.

i couldnt agree more! you have other things to get on your truck before a smaller pulley.

truck maintenance, AFR gauge, more fuel, smaller pulley.

more air is the best way to destroy your engine.

 

[Rockdawg84]

So i should hold off until I decide to pick up the 7th injector kit?

it doesn't have to be a 7th injector set up, could be AEM piggyback or water meth injection, or even others. You have a lot of reading to do so have fun :tea:

 

[Hepar]

Just try to visualize what you are trying to do. You are putting a smaller pulley on the SC from stock which will spin faster, right? Those pushing more air into it. But with the same max amount of fuel going into it. Engines run best when they have the best fuel to air mix. Too much fuel and/or not enough air, they run rich. Too much air and/or not enough fuel, they run lean. So, now you're going to shove more air into it without the ability for your engine to compensate with more fuel.

 

[ølaf]

Hey man -

reviving a very old thread....
Did you ever end up installing the 2.1 Pulley without fuel. mods? I'm in the front range as well, and do all my driving in the mountains, so ... contemplating the same thing. Doing the fuel pump doesn't sound very appealing.

- olaf

 

[mikeferg]

I live in Denver so fuel mods before small pulley is recommended and plus the gas here is only 91 so that on top of all things. at least get a Wideband so you can watch what's going on

 

[gamefreakgc]

Hey man -

reviving a very old thread....
Did you ever end up installing the 2.1 Pulley without fuel. mods? I'm in the front range as well, and do all my driving in the mountains, so ... contemplating the same thing. Doing the fuel pump doesn't sound very appealing.

- olaf

URD says that you can run the 2.2 if you live at high elevation and never drive near sea level. It increases the boost level from the 5-6 range up to 7-8 for our mountain friends which is what the stock pulley does at sea level. The 2.1 pulley will push it as high as 10 PSI which will cause severe long-term issues if you try it.

 

[mikeferg]

Did URD really say the 2.1 will cause severe damage?

 

[Formidable]

Just keep in mind the 2.1” pulley generates a ton of heat. The knock sensors and sensor wire directly beneath the supercharger have gone bad on multiple trucks running that size pulley for a reason.

 

[gamefreakgc]

Did URD really say the 2.1 will cause severe damage?

Before I added larger injectors, I fueled the 2.1" pulley with a methanol injection system. It ran out of fluid once during a road tuning run. My AFR sensor recorded a reading of 17.8 AFR at 11 PSI. I'm lucky I didn't crack a valve. Imagine doing that repeatedly and that engine won't last very long.