You are currently viewing our boards as a guest which gives you limited access to view most discussions and access our other features. By joining our free community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is fast, simple and absolutely free so please, join our community today!
If you have any problems with the registration process or your account login, please contact contact us.
Engine & DrivetrainDiscussions about the engine and drivetrain of your vehicle.
This is a discussion thread titled "Crank pulley size vs. Supercharger boost", within the Engine & Drivetrain forum, part of the Technical & Vehicle Assistance Forums category.
Alright .... I was lucky and just picked up a oem crank pulley real cheap off of ebay - i know a wizard who runs a michine shop - so all i need now is a formula to figure at what increment size increase on the crank pulley to increase the boost by one lb.? math experts step up to the plate
Alright .... I was lucky and just picked up a oem crank pulley real cheap off of ebay - i know a wizard who runs a michine shop - so all i need now is a formula to figure at what increment size increase on the crank pulley to increase the boost by one lb.? math experts step up to the plate
You need to know the original crank pulley dia. AND the SC pulley dia., this will give you the ratio...then you need to state the actual boost with this combination. From that you then can calculate boost increase.
BUT...how do you expect to increase the OEM pulley dia??...I see no way this can be done.
You need to know the original crank pulley dia. AND the SC pulley dia., this will give you the ratio...then you need to state the actual boost with this combination. From that you then can calculate boost increase.
BUT...how do you expect to increase the OEM pulley dia??...I see no way this can be done.
Kevin
ahhhhh i was hoping you would chime in here - you have the experience in this area. - i will get together the measurments then post them -
to answer the question as to how to increase the size - i thought that was the easy part my buddy Tommy at his machine shop can handle that part - probably just wrap/weld/ballance. i know you have looked into this, at least underdrive units, so why do you say this cant be done?
ahhhhh i was hoping you would chime in here - you have the experience in this area. - i will get together the measurments then post them -
to answer the question as to how to increase the size - i thought that was the easy part my buddy Tommy at his machine shop can handle that part - probably just wrap/weld/ballance. i know you have looked into this, at least underdrive units, so why do you say this cant be done?
The only possible way I can see would be weld, then remachine. If you do this it no longer will be balanced. As soon as you hit it with an arc welder you've lost balance. Plus...you would have to build up so much weld to effect the boost increase as you desribed...it would be totally impractical. Yes...you can remachine the pulley groove and make it run dead concentric to the crank drive ID...but you cannot control a weld perfectly uniform around the pulley and keep balance. Also heating up thin walls like on this pulley will warp the pulley.
Actually....I just thought of another way this can be done...by not welding...and it would maintain perfect balance Sorry....this is too valuable of an idea to just post...How many people do you suppose would want something like this??
The only possible way I can see would be weld, then remachine. If you do this it no longer will be balanced. As soon as you hit it with an arc welder you've lost balance. Plus...you would have to build up so much weld to effect the boost increase as you desribed...it would be totally impractical. Yes...you can remachine the pulley groove and make it run dead concentric to the crank drive ID...but you cannot control a weld perfectly uniform around the pulley and keep balance. Also heating up thin walls like on this pulley will warp the pulley.
Kevin
ahhhh i see your point about the welding - can i not increase its od then remachine then ballance it somehow ? how do they ballance my rods,crank,and pistons when i go in for a full ballance? i never stayed to watch the guys at the engine shop but there must be a way -maybe not?
ahhhh i see your point about the welding - can i not increase its od then remachine then ballance it somehow ? how do they ballance my rods,crank,and pistons when i go in for a full ballance? i never stayed to watch the guys at the engine shop but there must be a way -maybe not?
It's not that it can't be done...just on a small scale too expensive unless there is demand for it. Special balancing setups with tooling required would have to be made. The tooling alone would cost more then 3-4 people would want to pay. To balance they either would counterbore heavy areas to reduce weight, or spot weld weighted pads to incease weight in light areas.
I just checked my OEM pulley, it has been balanced...and has to be because it is 2 piece assy with small rubber insert inbetween.
Here is how you need to do it...I'll give you my idea
Turn the grooves off of the stock OEM pulley to achieve a full diameter. Turn a new pulley with new oversized grooves on OD and -.003 on the ID UNDER the OD size of new pulley OD. Put OEM pulley into liquid nitrogen for 30 secs, heat new pulley to 250-300 degs....and whoola...press on new pulley.
i knew you where the man - but....................... http://www.f150online.com/forums/arc...c/24575-1.html
if our design is the same as that eaton can never be done without wasting the blower damn - damn - damn !
thanks for the help on this but looks like this idea is going in the dumpster.
i knew you where the man - but....................... http://www.f150online.com/forums/arc...c/24575-1.html
if our design is the same as that eaton can never be done without wasting the blower damn - damn - damn !
thanks for the help on this but looks like this idea is going in the dumpster.
read the last post on that page - i feel as dumb as that a$$hole.
i knew you where the man - but....................... http://www.f150online.com/forums/arc...c/24575-1.html
if our design is the same as that eaton can never be done without wasting the blower damn - damn - damn !
thanks for the help on this but looks like this idea is going in the dumpster.
Maybe...maybe not. You need to see max RPM for the blower, find out where you are from that, calculate new pulley dia. and new RPM...and determine if you are still in a safe range. Also those numbers are for a lightening spinning 5500 RPM...Tundra cant go over 5200!
I've been thinking about this all night. I know that somewhere out there is and overdrive pulley designed to boost the 4.7L S/C a few psi. Couldn't a guy buy an ASP underdrive pulley for a s/c tundra but also install an overdrive pulley on the s/c?
Let's say the new s/c overdrive pulley was designed to produce 3 more psi. You install a 20% underdrive pulley from ASP along with the overdrive pulley. So in effect with new overdrive pulley the s/c is producing 9psi peak, but is 20% underdriven equals 7.2 max psi. However, the engine would also benefit from the recovery of the parasitic losses to the A/C, power steering and alternator.
This might be a good way for a S/C tundra to gain the benefits of an underdrive pulley along with an extra PSI of boost. It might not be a bad mod for the $200-250 both pulleys would cost you. Just a thought, don't know if it would be worth it.
__________________ 2005 Toyota Tacoma Double Cab 4X4
Speedway Blue Short Bed w/TRD Off Road Package, 2006 Tundra Wheels with 265/75R16 BFG AT KO's, Python 2-Way Remote Starter, Color Matched Hard Tonneau Cover
Ok fellas... I have put a LOT of effort into this one as well....
I WORK at a LARGE manufacturing facility and have 9 CNC and 4 plasma machines at my disposal. Also, a team of mech and electrical engineers that are my friends. I had a 99 Toyota Tacoma PreRunner V6 and made several S/C pulleys for it. It was.. as you said... hit or miss for a while.
The reason Toyota made a PRESS ON pulley for the M90 Eaton S/C is..
1. The feed and return belt paths are VERY close.... no room for smaller pulley there.
2. They wanted to keep the boost lower than the V6, beccause of mechanical failures in the driveline, not that the engine could not handle it.
3. To keep "us" .. ME from tinkering with it!
So... one last thing your overlooking too.. the stock crank pulley is also the harmonic balancer. I spoke to "the dude" in Texas that was banned here, and he sells a "boost kit" that is an aluminum crank pulley that is 1" larger and a fan pulley that is 3/4" smaller (to compensate for the crank pulley) and belt length. It was selling for .... if I remember... $350.00ish...
I started grilling him on the harmonic balancer and functionality without it. Also, the max boost I could achieve. He told me that the HB was over-rated and the MAX was around 14psi and I was to get a boost controller to "limit" the boost. Started adding up the parts and it was $700.00 or more.
Naaaaa.. not for me. I am working on making a crank pulley that is 1/2" larger, WITH a summit fluid HB bolted to the back. My Toyota tech buddy David told me that with out the HB, the front main bearing would fail.. pretty soon and the flex in the crankshaft and rod ends would "not be good". You NEED the HB.
I was going to make one and key it, and then lathe out a cavity on the back side to place the HB internally. It is a "work in progress"....
FYI..
SCDTRD
__________________ The Beast: 1994 Toyota Camry V6 XLE
The Mods:
Front tower Ractive Strut Bar, Whiteline rear AntiSway Bar, Rage Breaker 17.5x7 Rims and Falken Ziex 512 rubber, Limo Tint, Pioneer DEH 7700MP Head Unit, Polk 6x9 rear and Polk 6.5 Front speakers, Tokico struts front and rear, Carbon kevlar brake pads, Cryo treated rotors, ZEX 82021 N2O system, Polished and ported upper and lower intake runners, shift kit, and more to come.....and.... YES... it is a CAMRY....
So... one last thing your overlooking too.. the stock crank pulley is also the harmonic balancer. I spoke to "the dude" in Texas that was banned here, and he sells a "boost kit" that is an aluminum crank pulley that is 1" larger and a fan pulley that is 3/4" smaller (to compensate for the crank pulley) and belt length. It was selling for .... if I remember... $350.00ish...
FYI..
SCDTRD
Not true. The design I just suggested would RETAIN the Stock EOM Dampening capibilities. The stock pulley is not a harmonic balancer, it is rubber dampened...that is it. There is a big difference. Research this on the extreemly long UD pulley thread...I too have done my homework on this!
I've been thinking about this all night. I know that somewhere out there is and overdrive pulley designed to boost the 4.7L S/C a few psi. Couldn't a guy buy an ASP underdrive pulley for a s/c tundra but also install an overdrive pulley on the s/c?
Let's say the new s/c overdrive pulley was designed to produce 3 more psi. You install a 20% underdrive pulley from ASP along with the overdrive pulley. So in effect with new overdrive pulley the s/c is producing 9psi peak, but is 20% underdriven equals 7.2 max psi. However, the engine would also benefit from the recovery of the parasitic losses to the A/C, power steering and alternator.
This might be a good way for a S/C tundra to gain the benefits of an underdrive pulley along with an extra PSI of boost. It might not be a bad mod for the $200-250 both pulleys would cost you. Just a thought, don't know if it would be worth it.
I've read this cannot be done...reason being the pulley size would become too small, and belt slippage will occur. It's been attemped.
If 5 of you guys are serious about this...I can make 5 Stock OEM rubber dampened overdrive pulleys for $250.00 each + with your stock OEM pulley as the core charge. I already have the 1st OEM pulley...mine just sitting around. We just need to calculate the correct size, and agree on amount of boost.
ASP can make anything you want. They made our overboost pulleys from stock ones. We have been running them now for several months with no problems. They also balance better than factory. No fluctuations in rpm's, very smooth. Boost Around 10PSI
When you call them ask for Lee Cooper. Petros and myself have some expensive phone bills talking with TRD getting the sizes needed not to blow seals or engine up. Lee has those sizes on record.
If you are going to New England Dyno this weekend, I should be there.
Auto Specialties Performance Inc.
13408 Redfish Ln. Stafford, TX 77477
Monday thru Friday 8:30 am - 4:30 pm (cst)
Saturday Closed Sunday Closed
(877) 928-8678, Toll Free Order Line
(281) 261-8845, Tech Line
(281) 261-5715, Fax Line
Order E-mail: customerservice@aspracing.com
Tech E-mail: asp@aspracing.com
__________________
Seven years of mods and still not... or
Why do I keep fixing things that work?
Crank pulley size vs. Supercharger boost
my buddy Tommy at his machine shop can handle that part - probably just wrap/weld/ballance. i know you have looked into this, at least underdrive units, so why do you say this cant be done?
damn - damn - damn !
i feel as dumb as that a$$hole.
Chimin' in.....
Linear Mode
