Thread: Supercharger/blower questions

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NEW to site and its great the knowledge on here is unreal and every one seams real friendly. Ive got a few questions i hope some one can answer.First has any one used a weiand 250 blower? any good or bad experiences with it? How much lower is it than a 6-71 total hieght of carbs i know its 2 inches shorter than a 6-71. Teflon stripped how reliable are they? does it wear out or break off hate to think of damage it could do. thanks for any help ROD

lining holds up good long has you not sucking junk in or blowing things up the linings are still in my blower some may use telflon but there is another name of the stuff The blower shop . or BDS are good sites to check out . i have dealed with the blower shop for new and repairs very happy

PAT i really like your thinking about the higher comp ratio to start with -i allways laugh at the tractor pulls those turboed diesels they have them turned down so low on comp so they can run 30 some pounds of boost they wont even start with out either or rev up . MY problem is hood hieght with a 6-71 or 8-71. This is a toy itll never run on pump gas! I all but gave up on a blower until i seen the long rod rat artical in super chevy -it looks as tho it would fit the bill for me. Ide like to build one like it but a little differnt. Ide use AFR 345cc heads and for a cam a howards solid roller 260-270 dur @.50 .680 lift 114lc 3000-7000 rev range. Since its a smaller blower what static comp would you start with IM happy with the numbers they got but want the power band up higher THANKS PAT

the bm mega blower is about two inchs lower then the 671 or 871 as there no need for the carb plate to mount the carbs . i built some blower engins using the 345 just finshed i set for a hill and hole truck dart 355 heads that will use alcohol .did some offshore engines that used a smaller blower shop blower that is one i would use .you could drop the engine lower in to the car to cams i have used are about them numbers but lsa of 110

Thanks PAT im having trouble even finding the 250 blower for sale.Im sorry i thought it looked a lot lower than that. But for just 2 inches I guess ill have to bite the bullit on the height. Ill check out the blower shop small one tho thanks for the help ROD

no the TBS blower i think is lower then 2 inchs from the 671/871 my mega blower is 2 lower and is not a 250.it.s much bigger more like 420 cfm case is abit bigger then a GM 671 i would call or get on line look up the blower shop TBS and they may have specs on line

PAT i went to blower shop site and that tbs billet 250 looks sweet as dose the price its not that i cant find 250 blowers just worried about the belt would rather have a toothed belt.2 inches is 2inches but if its going to cost more than a 50hp loss- 2 inches isnt enough to mess with then. Got another question vacum since itll have 2 carbs holley hp,s that are boost referanced anyways can i run vacum to brake cyclinder off one carb the line on the back of base plate And run pcv valves that are teed together to the other carbs base plate line? DO you run any type of pcv valve or just let them breath out the valve covers

takes power to run the blower thats part of the game 2inch belt will be fine there is a photo of the smaller blower on my photo galley here that you can see there smaller blower. i a dealer for them and the blower case is machine out of a solid block so it.s a billet case very nice setup .as for holleys i done them but for the money i like AFBs/edelbrocks they may be abit lower on power who cares you be making alot of steam any ways and there very user friendly as for vac hook up under the carb base or BDS sells a valve that makes power brakes work but so will a vacuum pump on pcv i use open breathers i like the moons they work the best

PAT i thought that the carbs would have good vacuum since im not trying to go off the manifold ill check into that bds valve.The only vac i need is for the brake booster. DO you run vacuum advance on your blown motors i viewed your photo gallery and seen that blower you were talking about its the only single carbed and serpinteen belted one there that is a nice looking piece for shure 'How faroff will it be from a 6-71 in terms of power everything else the same cam, carbs; comp ratio

Rod, I have a B&M Powercharger 250 on my 406. It is the same blower you are interested in.
My engine is an after market Rodeck block with Brodix Track 1 heads. Crane roller cam. Here are the specs since you were talking about a cam that works in the 3000-7000 rpm range. This one's range is 3000 to 6500 with valve float at 7000. 539/558 lift, 292/300 duration @ .004 lift. This cam is ground on 112 LSA. I'm running dual Edelbrock 650's, one is a 1405 the other is a 1406, that are boost referenced. I also reworked them so the jets and metering rods are all the same between them. This is just for a baseline, I will tune from there. I chose this blower because I wanted it to fit under the hood (if I choose to run one) on my '31 Ford Coupe. I also wasn't interested in the little long snout blowers. This blower looks like a larger blower but fit my space requirements.
If you need a height measurement I could get you the dimension on Tuesday, as I worked all day today (Sunday) and will be working all day tomorrow. If you would like to check out my toy here is the link, Flickr: blwn31's Photostream. There are a few pics of the complete engine.
When I first got the blower and installed it, it was pretty noisy due to the rotor sealing Teflon strips. It quited down after a little run time. I have never had a problem with any of it coming loose. Now I haven't run the motor hard yet. I've put about 2000 miles on the blower so far. The motor will KILL my trans, so gotta upgrade it. My static compression is a approx. 8.52:1. I run this motor on 91 octane. One thing about this blower is it's a 4-71, so on a larger cubic inch motor you need to turn the blower harder to get the same boost. This in turn will limit higher rpm use without some kind of intercooler. I haven't had this motor on the dyno yet, but from what I've read this blower probably is done at about 5500 revs. For me this isn't an issue, no racing here.

Keith

Originally Posted by ratitude

PAT i thought that the carbs would have good vacuum since im not trying to go off the manifold ill check into that bds valve.The only vac i need is for the brake booster. DO you run vacuum advance on your blown motors i viewed your photo gallery and seen that blower you were talking about its the only single carbed and serpinteen belted one there that is a nice looking piece for shure 'How faroff will it be from a 6-71 in terms of power everything else the same cam, carbs; comp ratio

that engine with one carb is 1190 cfm and is a 502. carbs will have good vac and like said you could use the base plate of carb to hook to your brake booster BUT all the blower car never used a booster for bbc valve cover room . i taken edlebrocks AFBs out of the box put them on with out much work as for boost referencing a AFB never seen the need but . NO need.. i never seen to do this with the AFB carb has we did just about a W.O.T with engine with EGT on it . all the builds i done are with rollers Hyd or solid know for bbc and sbc i have done sbc with flat lifter cams many years ago but all rollers now . Smaller blower more CR less boost no need to over run the blower and make... Heat.... smaller blower s can work if you start at 9.5

KEITH yes ide like a distance if not to much trouble for ya. Go from end rail of block or bottom of intake where the end seal goes up to air cleaner scoop doesnt have to be dead on since youve got a small block and im doing a big block I viewed your pics you do some damb good work thanks alot ROD

No problem.

Keith

Since I've go the motor apart again, this is easy. With blower manifold on work bench with blower, carbs and air cleaner installed I've got 17 3/8". The height to top of carbs, take 3 1/4" off for air cleaner, I've got 14 1/8" tall.

Keith

KEITH thanks alot for the info ill have to see how high the ends up being on my car. thanks alot ROD