2.5 pulley install

[GT500Tow]

FYI, If any of you want a 2.5 upper pulley. You can use a belt sander to sand off the material needed to install a 2.5 pulley. It only takes a few minutes once the blower nose is off. Your removing 1/16 of an inch of material from each side of the nose..Tape it up good with masking tape before you start. So no dust gets inside of the blower drive gear housing. Pressed on pulleys really need to be pinned. Or at least install a bolt in the center of the pulley shaft. Especially if your running small upper pulley and 10% lower pulley. I've always wounder why it didn't have a what i would call a safety bolt in it from the beginning. I know the Lightnings and tems did. I've been runing a 2.5 upper for a while. No problems so far and my car has many 1/4 mile runs on it. No belt slip at all. I also don't run a belt tensioner of any kind. 2.5 pulley cost is 150. You'll need supercharger oil. Ether buy two bottles or you can use 50W redline racing motor oil. So a 2.5 isn't expensive to install and can be done in two hours. Great mod for a stock blower.

[Justin00Stang]

IMO, I would not use a belt sander. I would set it up in a mill and properly machine it down. You don't want to go any thinner than 3.5mm on the wall of the snout (5mm is stock).

 

If the snout is not properly clearanced, the pulley will grab and spin off the blower shaft (hence your requirement to pin).

 

If its clearanced properly and the bore of the pulley is machined to eaton press fit specifications, there is no need for pinning. The bore is where a lot of people mess up, for some machine shops its hard to hold 5 tenths on a pulley bore. Attached is the OE spec.

 

I believe metco has discontinued the 2.5 pulley that you have Tow, due to lack of interest.

[GT500Tow]

IMO, I would not use a belt sander. I would set it up in a mill and properly machine it down. You don't want to go any thinner than 3.5mm on the wall of the snout (5mm is stock).

 

If the snout is not properly clearanced, the pulley will grab and spin off the blower shaft (hence your requirement to pin).

 

If its clearanced properly and the bore of the pulley is machined to eaton press fit specifications, there is no need for pinning. The bore is where a lot of people mess up, for some machine shops its hard to hold 5 tenths on a pulley bore. Attached is the OE spec.

 

I believe metco has discontinued the 2.5 pulley that you have Tow, due to lack of interest.

 

 

Its very easy to do with a sander. Just take you time and only take off what you need. Just install the pulley and let it mark where the material needs to be removed. Very simple process. The clearance is easily checked as you go. The only reason i said anything about a pin is. Because of failures from other members running small pulleys with a TVS blower. Mine inst pinned and is fine. I called metco and they said if i wanted anymore that they could make some up. Besides any 2.5 will work fine. Here's the thread of captain bobs TVS that the pulley fail on. It wasn't the first one to fail. .

http://www.teamshelby.com/forums/index.php?/topic/56026-having-some-issues-had-to-cancel-the-track/page__p__956210__hl__%2Btvs+%2Bpulley+%2Bfailure__fromsearch__1#entry956210

[Justin00Stang]

Cobra bob has been running a tvs for a very long time, he has one of the original frpp/harrop units wih the tapered snout. When the TVS first came out people were taking a regular GT500 2.6 pulley and putting it on the TVS, this doesn't work for two reasons. First, the tvs snout is slightly longer, second, its tapered and 1/8" larger diameter in the rear. If you try to press it on further to make the belt alignment correct, you just reduce your clearance to the snout as it gets larger as you go farther back. I tested this early on and there was only about 10 thou clearance. When an aluminum pulley flexes just a hair its going to grab and fail. I know all of this because i was in the process of designing my first pulley when the tvs came out, when we got the tvs on my car and saw the tapered snout we immediantly changed the design to increase clearances.

[GT500Tow]

I'm not sure what your talking about. "Grab and fail" Ive been running top and bottom aluminum pulleys on my Eaton for ten years with out a single failure. So have many, many other Lightning and Term owners. I've probably have made 400 + passes and have 90 thousand miles on my Lightning. I also sanded down the nose on it. I have three pulleys that i swap anytime i want. Also you advertise the same pulleys for a TVS or stock blower. Now your telling me that the TVS pulleys are special. What ever. You'll figure it out. Just look around a little. The aluminum pulleys just need to be hard anodized. Most are....JFYI, Bobs car didn't have an old TVS blower. It was only 7 months ago. "Hence check date"

[Justin00Stang]

I'm not sure what your talking about. "Grab and fail" Ive been running top and bottom aluminum pulleys on my Eaton for ten years with out a single failure. So have many, many other Lightning and Term owners. I've probably have made 400 + passes and have 90 thousand miles on my Lightning. I also sanded down the nose on it. I have three pulleys that i swap anytime i want. Also you advertise the same pulleys for a TVS or stock blower. Now your telling me that the TVS pulleys are special. What ever. You'll figure it out. Just look around a little. The aluminum pulleys just need to be hard anodized. Most are....JFYI, Bobs car didn't have an old TVS blower. It was only 7 months ago. "Hence check date"

 

 

Tow, the GT500 pulley design is completely different than a cobra or lightning that you are so familiar with. The cobra and L pulley is almost centered, the GT500 pulley is offset at least 1.5" to the rear, over what I call the "snout" of the blower. That leaves a lot of room for flex and the potential to grab if there is not enough clearance.

 

Regardless of it happening only 7 months ago, he has had that blower on there for around 3 years. I refer to old TVS as the original version which was made in Australia by Harrop. The ausies do things their own way and have some different ways of machining the snouts (hence the taper) and also use non-standard shaft lengths and offsets.

 

You are correct, I sell the same pulley for stock and TVS. I was able to "split the different" in shaft lengths and design a pulley that works well for both, so the customer does not have to pay for a new pulley if they upgrade blowers. I design all my own pulleys and have sold hundreds with zero failures. I have measured all the different blower designs and I am intimately familiar with what is needed. Had Bob or anyone else been running one of my pulleys, they would not have had a failure.

[GT500Tow]

Tow, the GT500 pulley design is completely different than a cobra or lightning that you are so familiar with. The cobra and L pulley is almost centered, the GT500 pulley is offset at least 1.5" to the rear, over what I call the "snout" of the blower. That leaves a lot of room for flex and the potential to grab if there is not enough clearance.

 

Regardless of it happening only 7 months ago, he has had that blower on there for around 3 years. I refer to old TVS as the original version which was made in Australia by Harrop. The ausies do things their own way and have some different ways of machining the snouts (hence the taper) and also use non-standard shaft lengths and offsets.

 

You are correct, I sell the same pulley for stock and TVS. I was able to "split the different" in shaft lengths and design a pulley that works well for both, so the customer does not have to pay for a new pulley if they upgrade blowers. I design all my own pulleys and have sold hundreds with zero failures. I have measured all the different blower designs and I am intimately familiar with what is needed. Had Bob or anyone else been running one of my pulleys, they would not have had a failure.

 

 

Your right, they are a lot different. Probably because of the 10 rib belt. Just good to hear you have a fix. Me and Bob were not friends. But i hated to see him get let down like that. His goal was to run a 10 second pass. Then shorty after he did the pulley flew off. I'm sure that was a big disappointment for him. We all have bad days modding our cars. Some worse then others. I'm not picking on you. Just try to keep others from having those bad days of modding. That's why we should be able to search these forums anytime we want. It helps us all in the end. For one your not selling parts that piss people off and we have a dependable hot rod. That we can drive anywhere and have fun with. So thanks for the info.