roots blowers

im wondering how much compression and stroke i can run with alot of boost just kickin around turnin my 4.5 stroke c head motor into a blower motor set up. be mud drags short hard bursts. and ill have to run alot of boost to compete . brad

Run as much stroke as you want. Keep compression as close to 8 to 1 as possible. There are lots of off the shelf pistons for a 4.5 stroke that can get you there with around 90-100 cc heads, and custom pistons for smaller chambers. Run race gas and keep you temps under control and make some huge power!

Can you run alky? I don't know much about your racing. Guys that run with us with roots blowers usually run around 12:1 on alky. A couple of them run almost 40 pounds of boost.

Roots Blowers are iconic they and the Tunnel Ram were the things to have in the late 1970's-Early '80's Pro- Street movement.

Roots Blowers move a certain amount of air based on the size of the blower case & how fast the boost pulley is spinning.

As an example use a 472 CID BBF with an 8-71 Supercharger.

An 8-71 moves about 436.29 cubic feet of air every rotation of the crankshaft assuming a 1:1 pulley setup.

(436.29X25.58/ 472)-14.7 ( 1 Atmosphere)= approximately 8.9 LBs of boost.

Lower static compression will allow for more boost.

Hope that helps.

511Fox wrote:Roots Blowers are iconic they and the Tunnel Ram were the things to have in the late 1970's-Early '80's Pro- Street movement.

Roots Blowers move a certain amount of air based on the size of the blower case & how fast the boost pulley is spinning.

As an example use a 472 CID BBF with an 8-71 Supercharger.

An 8-71 moves about 436.29 cubic feet of air every rotation of the crankshaft assuming a 1:1 pulley setup.

(436.29X25.58/ 472)-14.7 ( 1 Atmosphere)= approximately 8.9 LBs of boost.

Lower static compression will allow for more boost.

Hope that helps.

so what size roots blower would be best on a 584ci. 4.650x4.300 ,, 8.1 compression on gas

yes if i build one it will be an all out deal on alky and a screw blower . i know i will need alot of matinace . the guys in the class run really hard . dominated by the hemis and a few chevys theres one ford thats running that i know about paper boy express he runs ford hemi heads on a c@c block . i here it will take 2500 plus horse power . reason i was rethinking was i need to redo the tubes to get my tall deck block in . i was fitting it and the heads hit the tubeing . brad

If you are certain you want a Roots Blower you need to talk to BDS about a 10,12 or 14-71.

I would talk to Don Hampton www.hamptonblowers.com One of the oldest blower shops around and Dons customer service is awesome!! He was a Top Fuel driver and has been doing blowers since the early 1960's. The guy flat knows his stuff. Everything in my 460 kit was perfect, and the motor screams!! HIs phone # is : 562-803-9484

When it comes to Fords BDS sucks big time. I would go to B&M before I would go there (and yes that is sarcasm).

blown473 wrote:I would talk to Don Hampton www.hamptonblowers.com One of the oldest blower shops around and Dons customer service is awesome!! He was a Top Fuel driver and has been doing blowers since the early 1960's. The guy flat knows his stuff. Everything in my 460 kit was perfect, and the motor screams!! HIs phone # is : 562-803-9484

xxx100...

jasonf wrote:When it comes to Fords BDS sucks big time. I would go to B&M before I would go there (and yes that is sarcasm).

Sorry about that seems alot of the Mopar crowd was happy with BDS didn't know their stuff wasn't as good for BBF.

Hampton won't just take your money and throw a kit at you and let you figure it out. He will take the time to go over you whole motor with you, your design goals and set you up with what you need to reach those goals. He sells other parts besides blowers, heads, cams etc. He will custom make a part if needed. The most interesting thing about him is he works 7am to 7 pm daily and answers the phone himself! I have called him dozens of times for advise as I changed my drive ratios and tune, and his knowledge was priceless. I have since sent several friends to him and they have had the same experiance with him. A super guy to deal with.

511Fox wrote:
Sorry about that seems alot of the Mopar crowd was happy with BDS didn't know their stuff wasn't as good for BBF.

I am surprised to hear that. A friend of mine that builds quite a few blower motors every year said he has had complaints from his mopar guys about BDS.