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what do I look for in used root blowers


mobythevan

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I don't know much about superchargers but they seem pretty simple. So what would I look for in a used supercharger? Just play in the rotors. How long do they last? Holley/Weiand/B&M are all the same company right? There doesn't seem to be much to where out on them.

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The wear items are the Teflon strips on the edges of the rotors. Most blowers use these. You can convert a blower from a large diesel. To convert you need to change the drive unit (new unit can be bought from BDS etc.). If converting from a truck the best unit to get is the 6-71 blower off of a Detroit Deisel because the standard blower manifolds are built for these. You may also want to look at Magnusun sp? blowers.

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Eaton makes a lot of OEM superchargers for ford, GM and mercedes, as well as aftermarket superchargers for magnusson and TRD. A lot of their kits are well designed, but are application specific. Eaton superchargers have a good reputation as being very reliable, good for 100,000 miles. Change the nose gear and go another 100,000. The boost on these are almost instantaneous when you mash the gas (I have one on my truck)

 

This is nice write up on the TRD supercharger: http://www.gadgetonline.com/Super.htm

 

I thought sombody attached an eaton m-60 a while back on this site. If I remember correctly it was mounted on the passenger side. I don't remember if the setup worked well, but it was neat to look at.

 

B+M is now Holley, Weiand is a seperate company. Two slightly different philosophies on rotors. One uses teflon tipped rotors the other uses tighter tolerances that they can get away with because of a stiffer casing, at least thats what there marketing guys say.

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Welcome to the Dark Side of forced induction. I am in the middle of designing my supercharger project. I have an Eaton M62 supercharger off of a Mercedes SLK230. It has a clutch like an air conditioner and a short front shaft. I am planning on installing it where the air-conditioner compressor was located. The Eaton supercharger rotors are Teflon coated and have grease packed needle bearing in the rear. From looking at mine check that it spins freely and the coating.

 

I am designing for around 9 psi of boost. I found a vendor that sells after market lower pulleys for the Ford Lightning that I am planning on using.

 

Here is a rough spread sheet on HP to Boost.

 

boost001.jpg

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Just as a note of caution on those eatons. I've heard the pulleys are difficult to remove without damaging the nose piece. I guess it requires a special gear puller. I found these guys a while back who sell different pulleys and a puller: http://www.pulleyboys.com/

 

By the looks of their design you could probably make one yourself if you have the tooling.

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I'm going the route of making changes to the crank pulley to change boost. This company makes 4 pulleys from 7.9 to 9.75" in diameter for $80 each. All I have to do is design and have machined the center addapter.

 

20031712231513mtb4403823qf.jpg

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If you are doing a diesel blower it is recommended that you double pin the rotors, they don't take alot of work, just truing up the ends and making sure the clearances are right, add rear bearing support plate and front drive. There are two different gear angles and both cast and steel gears on stock blowers. Know which is which before buying. Teflon strips are for stock cases with flex that have been mentioned, most blowers are now using tighter tolerances but that can have it's own can of worms. Roots lowers can last 60K miles between rebuilds on street machines, they run in their own oil so you have maintenance there. They are easy to rebuild with bearings and seals, if you can do a carb, you can do one of those as long as your not changing clearances.

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I currently have a weiand 6-71 blower on a sbc on a 1970 240z. Dont be fooled by a low cost diesel pulloff. Rather than piece a unit together from parts you are much better off getting a complete kit from weiand. I bought mine in pieces and I can say that after $120 each for pulleys. $110 for a new popoff. new v belt pulleys etc, gaskets, 2x4 adapters etc. you can spend alot more than what the kit costs.. Most of us don't have the proper equipment to properly clearance a blower for gas duty. There are also some reputable blower rebuilders that can provide you with an already rebuilt blower at a price that would still beat you rebuilding a blower yourself.

You can try JR. in Grass valley Calif. He comes highly recommended and can set you up with a rebuilt 6-71 or 8-71 at a great price.

 

Try him at (530) 292 3368.

 

6-71 Blown SBC 240z

4 link on narrowed 9 inch rear

15.5 MT /centerlines

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I currently have a weiand 6-71 blower on a sbc on a 1970 240z. Dont be fooled by a low cost diesel pulloff. Rather than piece a unit together from parts you are much better off getting a complete kit from weiand. I bought mine in pieces and I can say that after $120 each for pulleys. $110 for a new popoff. new v belt pulleys etc' date=' gaskets, 2x4 adapters etc. you can spend alot more than what the kit costs.. Most of us don't have the proper equipment to properly clearance a blower for gas duty. There are also some reputable blower rebuilders that can provide you with an already rebuilt blower at a price that would still beat you rebuilding a blower yourself.

You can try JR. in Grass valley Calif. He comes highly recommended and can set you up with a rebuilt 6-71 or 8-71 at a great price.

 

Try him at (530) 292 3368.

 

6-71 Blown SBC 240z

4 link on narrowed 9 inch rear

15.5 MT /centerlines[/quote']

 

 

Hey Okiez, welcome!, any pics of your car?

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What's the application? That makes the biggest difference, but, no matter what, I wouldn't but a diesel blower. If you could find a Detroit Diesel, it would have to be ancient, and therefore in ancient shape. I'd steer more toward more modern Eaton units (Buick 3800 M90, Mercedes M63, Cobra M112).

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I still use 6-71 and 4-71 detroits on several water pumps, parts are readily available and cheap, a 6-71 kit is about $1000 which includes pistons, bearings, gaskets, liners, pins, rings, injectors etc. Blowers never go out on these, at least I've never had one go out cause they run with circulated engine oil, which is not the case in automotive applications. I have a 8v-92 in an excavator and an 6v53 in my 25 ton crane as well. I built a 6-71 blower in college machine class and it is very expensive to get the drive and rear plates. I made my own rear plate out of a stock rear plat that was machined for steel rings to support the bearings. Double pinned the rotors, tightened the clearances on the ends of the rotors and that was about it. It was interesting and alot of fun.

 

The designation 4-71 means 4 cylinder and 71 cubic inches per cylinder. It is the same for all of the 71,53 and 92 series engines. The 8v92TT "silver 92" pumps out 440HP and around 1400 lb-ft tq, wow, twin turbo's and blown. My dad had a '77 Peterbilt with a 12v71 that had twin turbo's and twin blowers and made 600HP. It was bad to the bone, but I was too young to drive it and it got wrecked before I got my license.

 

The kit is definately the way to go and way cheaper.

 

Post some pic's Okiez.

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My application is for a 454 for towing in my 1 ton truck. I wanted to tap into some of the knowledge on this site and also have a thread for other people looking into used chargers for hybrid z cars. I went ahead and bought a B&M 250 supercharger. Got the charger, carb plate, belt, pulleys for $1000. It looks like it is in good shape. It has the teflon strips on the rotors. It has 16 rib pulleys because it came off a boat.

 

My major question now became.... can I run the supercharger dry? I have an EFI manifold and I want to set up with megasquirt and just put a throttle body on top. Holley's official stance on this is that the fuel helps cool the rotors. They said if I don't run it at high rpm it would "probably" be ok. I will only run 6 pounds of boost for this setup. What do you guys think?

 

Other guys that use the EFI manifold told me that they add a few injectors on top the charger along with the multi port injectors. Megasquirt would allow me to do stuff like that, it just isn't what I intended. I just wanted the simple multi port EFI, supercharger and 6 punds of boost for towing.

 

BTW, my dad had a log truck with the silver 92 and it did run good. Impressive to see what a truck can do with 86,000 pounds. The last log truck he owned had a Cat inline 6 550hp. Awesome.

 

8239S_bbc_super3-med.jpg

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That's an impressive set up there. I am amazed at what 6 psi will do in a big block chevy, I think you will too. Dry, well, I don't think that'll work very well and if it doesn't you'll be buying another blower. Probably a good idea to inject at the intake of the blower and make use of the latent heat of vaporization.

 

When rebuilding the blower for wet, you take out clearance, conversly, if you run it dry then you should add clearance back to stock diesel spec's. There is clearance between the ends of the rotors and case ends, rotor to rotor and rotor to case sides, that is what you deal with, all easily measured with a standard feeler gauge. Rotor to case is based on radius as is rotor to rotor, and the ends will both close up as the blower heats up, actually all of it will tighten up. The case expands as it heats so that doesn't have as much of an effect on things as does the rotor to rotor and end play between the rotors and end plates. I'm guessing that if you have a problem with clearance running dry, it'll be with the end plates and when that clearance runs out it locks up the blower big time.

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Ok, here is what I am thinking now, run two 160lb/hr injectors at the throttle body. I had planned to run with 36-42 lb/hr on each cylinder in multi port mode. But I can easily set up to have throttle body type injection and solve the cooling rotor issue. I am staying with fuel injection because this project is another chance for me to play with megasquirt.

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If you run a wet supercharger you cannot run a intercooler due to possible explosion. I would be dangerous to have all of that volume filled with a gas mixture and have a back fire. Also on the eaton supercharge, from my research, gas will remove the teflon coating.

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I take it the eaton chargers must be built to be dry because they are used in port injected set ups. Apparently the holley/weiand/B&M stuff is not. That is directly from Holley that they recommend fuel through the charger even with the teflon strips in the 250 charger like I have.

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Really, you can't run an intercooler with a wet blower. I guess all the boating crowd never got the message and my buddy Gabe has been playing with fire for the last 8 years with his intercooled 8-71 blown 454 jet boat. I don't think I buy into that assertion, seen too many that are wet and intercooled on boats.

 

I think what your getting at is that intercoolers for blowers are mostly wet and require a large volume of cool water, which is readily availabe only to the boating crowd.

 

I have seen several water to air coolers on some turbocharged mustangs at the strip, but that is a complete pain in the %$&*.

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Thanks for the welcome guys. There is snow outside right now in Oklahoma but I'll bring it out of the garage and get some pics up here hopefully by the weekend. My Z is still a work in progress as I had a back injury working on it three years ago and after many operations I am still am not totally recovered so it takes longer now and is more painful to do the work on my project. I should probably name it "Blood Sweat and Tears" but I call it "craZy". I have done all the welding, fabrication, design, engine, etc myself in my garage at home. I was inspired by Barkley’s Z in Wichita. I had thought about a big block Mopar originally but my son stole the engine for himself. So I decided to build a blown 350 small block instead. My plan is to run this on the street for awhile. I will probably begin building a separate Bickel style tube frame to transfer everything to at a later date while still keeping it street legal. Here’s some of the details

 

6-71wieand blower 15% underdriven

8.5 to 1 compression

Comp Cams blower grind

Dual edelbrocks 600’s.

electric water pump

Crane XR ignition inside a stock distributor housing

Aluminum motor mounts

Chrome valve covers, oil pan, timing cover etc

Headers

Supertrapp mufflers

Rebuilt TH350 trans with new internals, shift kit, loose converter, and

starshifter

Frame from the firewall rearward replaced with 2x3 tubing and roll bar rewelded a new floor into place

Rear four link using adjustable coilovers

The front suspension is converted to adjustable coilovers and long studs with toyota truck calipers

braced ford nine inch is narrowed to 36 inches wide

3. 89 gear with 31 spline axles

Mickey Thompsons in the rear, skinnies on centerlines in the front

I have wheelie bars and will probably mount them for shows and the track

It uses an rear mounted optima battery

Mopar master cylinder with proportioning valve

painless wiring harness

ten gallon fuel cell

holley blue pump

summit fuel filter

aluminum hard lines and braided stainless and AN fittings

Polished aluminum firewall

removed the drip rails

welded in stock sail panel vents.

removed the gas filler

reradiused rear wheelwells

converted the rear taillights to corvette style, dual round taillights.

Front and rear spoilers

Custom hood vents

Custom grill

Cowl induction hood

fiberglass bucket seats and 5 point harnesses.

GM tilt column with custom steering wheel

The dash is handformed sheetmetal and aluminum.

 

I currently have the paint to do a basecoat/clearcoat black paintjob with House of color blue pearl overcoat.

 

Like I said I'll try to get pics this weekend

 

THanks

 

Phil Ingram -Okiez

 

 

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