1GR-FE 2.0” drive pulley on TRD supercharger

May 11, 2018

1GR-FE 2.0” drive pulley on TRD supercharger



So, as an insane modder I decided I wanted to push the lower limit of small pulleys for the TRD supercharger for the 1GR-FE.

I intended to order a 2.4” pulley, then thought why not go 2.2”. With a quick check on eBay, there was a 6-rib alternator pulley advertised as 2.2”. I ended up getting sent one that was 2.0”… and I said, naturally, why the heck not install that.

The biggest problem was figuring out how to modify this 2.0” pulley to fit on the shaft without significant expensive machining work to either the pulley or the shaft. Essentially this describes how I did it.

Note, so you guys know, I have the UCON-EMS. Prior to this pulley I was using the 2.825” stealth pulley. The 2.0” pulley increased (according to my in-truck boost gauge) the boost from 6psi peak at WOT up to 13psi peak at WOT. Dyno results will be posted eventually, but the truck runs great and is noticeably faster. And louder.

Also, because I know you want to know, the stock injectors (from the TRD supercharger kit) along with the URD 7th injector supply enough fuel to run this pulley – I do not lean out at redline RPM and WOT, not even a little bit. The UCON-EMS keeps me at about 11 for AFR all the way up to redline.

EDIT: I did install a water/methanol injection kit after talking with some of the other boosters on the forum. The truck was hogging down a lot in hotter weather without it - probably the EMS pulling timing. Or, just a way less dense intake charge from compounding heat inputs - boost, intercooler, intake, supercharger all adding their heat...

Parts needed:

- Black 2.0” pulley (alternator pulley with 5 or 6 ribs recommended – found on eBay) Note, may be advertised as some other diameter, such as 2.2”. It is the inside diameter (where the belt goes) that is 2.0”.

- Stock supercharger pulley

- Spacers (washers) for idler pulleys

- Shorter supercharger belt (69.4” as opposed to 70” for stock)

- Quantity 6, 4mm bolts (M4x0.7)

Tools needed:

- 1.5” metal hole saw with adapter to fit in drill press

- Drill press

- Hand drill

- 13/16” drill bit

- 1/8” drill bit

- 3/16” drill bit

- Red Loctite

- Brake cleaner

- A few small files

- M4x0.7 tap

- Toaster oven

- Wrenches

- Dremel with cut-off wheel

- Angle grinder with grinding wheel (NOT a cut-off wheel)

- URD pulley install tool

- Dark grey enamel brush paint

- Gloss black enamel brush paint

- Painter’s tape

Steps:

1. We are assuming you’ve already found a way to remove your current pulley. That is not covered here.


2. Use the 1.5” hole saw and the drill press to remove the center (hub) of the stock (3.0”) pulley. Take great care that it is centered before sawing.

a. IMPORTANT NOTE: I don’t recommend using the Stealth pulleys for this, because they are made out of aluminum (I think). Use the stock pulley (3.0” pulley) because it is made of steel and will allow you to use higher torque on the bolts to attach the stock pulley hub to the new pulley.

b. IMPORTANT NOTE: Be very careful not to damage the inner surface of the stock pulley’s hub at any point – make sure it stays smooth. Otherwise you might have trouble getting the new pulley onto the supercharger’s drive shaft, and you’ll be swearing for days at the Universe for treating you so poorly. The outside of your new pulley will probably get scratched in the process of drilling, which is why we need the black enamel paint.

3. Drill out the center of the new unmodified (2.0”) pulley with the drill press and the 13/16” drill bit. This will ensure the new pulley will fit around the supercharger drive shaft. You don’t need it to be exactly the same measurement as the drive shaft, only a tiny bit bigger – but not a lot bigger (which is why I recommend a 13/16” bit). Sorry, didn’t take any pictures at this stage.

4. Use the 3/16” drill bit to drill two holes approximately 180 degrees from each other in the backside of the new (2.0”) pulley. Then, use these as guide holes to drill, using the 1/8” bit, through them into the BOTTOM of the hub which was removed from the stock pulley. Tap threads the 1/8” holes with the M4x0.7 tap.

a. IMPORTANT NOTE: Be very careful drilling into the pulley hub. Test the location of the drill bit before you start drilling, at least four times, to make sure you won’t be drilling partially outside the hub, or into the annulus of the hub that will slide onto the drive shaft. My drill press was cheap, so the bit had a tendency to drift on me. But, I got lucky and all the holes worked out. You have to be good to be lucky I guess.



5. With the pulley and hub assembled using two bolts and the first two holes, drill the other four holes through both pulleys with the 1/8” drill bit. Again, be really careful, like as careful as you ever have been with anything, because if you fuck this up, you’ll be waiting for new parts in the mail and be cursing the Universe again.


6. Disassemble the pulley and hub, and ream out the holes in the new pulley (2.0”) with the 3/16” bit. This will allow you a bit of wiggle before you torque the bolts down so that you can get the best alignment possible before final assembly.


7. Clean up all the flash from drilling, you’ll probably find lots of it around all the holes on both the inside and outside of the new pulley. Use a file, a chisel, countersink drill bit, whatever.


8. Loosely assemble the hub and pulleys and get the hub into the best (most concentric) alignment possible. I was able to get the alignment to within about 0.5mm, which didn’t present a problem.



9. Test that the NEW pulley’s hole clears the drive shaft completely by sliding it a few millimeters onto the drive shaft. Adjust the alignment if necessary.



10. Clean your bolt holes and bolts really well with some brake cleaner, then let it completely dry. My favorite product is Brakleen. Put some red Loctite in each bolt hole in the hub, install it with the new pulley using all your bolts, torque everything down. I used about 70 inch-pounds per bolt. You may need to iterate tightening the bolts again several times. I personally had to iterate torquing them about 7 times.



11. If you need to, go in with your dremel cut-off wheel to remove parts of the bolt heads that stick into the path of the drive shaft. Test fit the pulley a couple of millimeters on the drive shaft again to make sure you got it all.


12. URD makes a tool to grind off the supercharger snout for smaller pulleys. I opted to just use an angle grinder. Do whatever seems best to you.


13. Put some painters tape – about four layers – on either side of the drive shaft on the snout. This allows there to be a tiny gap between the snout and the pulley so you can’t push the pulley too far onto the drive shaft, causing rubbing during operation and probably belt slip, then a fire, explosion, and whatever else.


14. Use the URD pulley install tool to install your new pulley. See URD’s instructions on this for further details. I used a toaster oven instead of the boiling water idea that URD recommends for heating up the pulley.



15. Spacer the two idlers directly below the supercharger drive shaft. The amount of spacering will vary depending on what your alternator pulley looks like. I needed about 3/16” of spacering. I found some perfect ones left over from my car’s engine installation. I can’t remember what they were originally for, but they are made of some pretty damn hard steel.



16. Use your enamel paint to touch up the supercharger snout and pulley. Wait about 24 hours for the Loctite to set.



17. 24 hours later, after not being able to sleep out of excitement, install your supercharger belt.



18. Turn on your truck, floor it, and drift into a tree or a brick wall.

EDIT: I ended up installing a third idler below the supercharger drive, to add more tension to the belt. I got a beautiful idler at the auto wrecker's. it's adjustable so I can release the tension on the auto-tensioner, then add more tension by adjusting the third idler, to my heart's content. I did notice better throttle response and possibly more power after I did this. See below...



EDIT AGAIN: In doing research on belt slip (which became apparent after talking with @12TRDTacoma and others about tiny drive pulleys, I added a shorter (69") Gates Fleetrunner belt -- part number K060690HD. Note it is a 6-rib belt that you'll have to cut one rib off. Mount a razor blade in a vice to cut it for the best results. The belt offers superior traction over cheaper belts, and hey, it's green which is cool.

Also, the addition of an upper idler and subsequent re-routing of the belt in the below picture gave even better traction on the drive belt and immediately netted me another pound of boost or two.

 

That's awesome! Might I suggest using a pulley wrap mod like this one @Roostfactor made? It prevents belt slipping with smaller pulleys. Great write up!

 

@White lightning boosted

That's a fantastic idea. Thanks. I don't think it's slipping right now - seems to hold 12-13psi all the way up to redline... but it would be a super cheap and easy mod so seems worth it in any case.

 

You won't realize its slipping until you do the mod. Contact @Roostfactor if you dont want to make one. He's a great guy. Buy one of his

 

Your 12-13 might be more. Or more useable.

 

@White lightning boosted That's true. I'll do it. I'll be a fun mod. And a free one, if I can smuggle an idler out of the pick-and-pull

 

Awesome man! Have you checked out the supercharger thread here?

 

Sure have! Already did an oil change AND replaced the rear bearings! I have the thread in my favorites.

 

What oil did you use? I bought Lucas oil, need to do it still.

 

I just used the GM stuff which I understood was replace in kind. What is this Lucas you speak of? Not sure I noticed that when I read through the writeup.

 

I found it on Amazon. It's for Kenne belle superchargers. Its rated for ours. Figured Lucas oil products were good stuff.

 

Cool. I am thinking I'll do my second oil change. Although the first time I did it (at 60k miles approx) it was pretty clean still.

 

Well done. I bet that engine screams now!

Which size injectors are you running?

As a side note, have you heard of the Pulley Boys quick change pulley?

 

Thanks @Torspd ... feels pretty much amazing to get rep from a juggernaut of Tacomas like yourself.

I am running the stock TRD supercharger injectors (455s I think they are?) and the 650 7th injector from URD. Been redlining it quite a bit the past few days and AFR doesn't lean out at all. Note it's about 60 degrees here... not sure if when it's -25 degrees I'll start to lean out.

I have looked at the quick change pulleys yes. Too professional-looking for me. Lol.

 

As a precaution for all of your labors, if you can do a datalog, when you have the chance, get one. Your 7th is greatly helping keep knock at bay. Very glad you have that. Those 455's have got to be near or at their max duty cycle. I don't want to see that hard work not continually bear fruits.

Want to keep a positive eye out for you, if you hadn't thought about that yet.

 

Datalog would be most beneficial. @loginfailed had I believe 95% duty cycle on his 455cc injectors with the 7th at about 40%. This was with a 2.55 pulley.
What this means is the 7th MAY increase duty cycle if required. I have only seen it up to 40%ish.
That is some crazy rpm the sc is running now. Definitely way outside the efficiency island but hey if it's working then boost on! This is the most boost/fastest rpm sc I have heard of on our trucks except one guy years ago that did the "snakebite" mod to his. He got 16 psi, no 7th that I know of, and blew the motor before he ever hit redline.

 

How did you change the rear bearings? Is there a link?

 

I changed mine before I even installed the sc (took it apart to port match). I used Jon Bond Performance fluid found here:
https://jonbondperformance.com/index.php?main_page=product_info&cPath=1_2&products_id=1

 

Do tell about this snakebite mod. So I can make sure I don't do it.

 

I don't know what to tell you guys. My boost gauge reads 12-13psi all the way up to redline and WOT, and my AFR gauge reads 11.0 all the way up. I have been flooring it everywhere and redlining it quite a bit for about 300km now. I also did something similar to my car, it is running higher compression than our trucks (10.5:1) and I am running 12-13psi of boost (coincidentally) after a professional tune. There's no 7th injector on that of course, so they pulled a lot of timing. I'll see if I can get some data logs and let you guys know what duty the injectors are doing.