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cody nobbs wrote:

Emailed him the other day said hes making more in a month or two and its a 2.5 outlet thanks tho man

And here I thought I knew about something that no one else did haha.

Thats a tiny ass pulley. Ive never seen one that small.

-Z Yaaaa- wrote:

1.9" pulley?!!?!??! damn bro even im not that @!#$n crazy lol

false, had you known about it you would have run it lol.

"In Oldskool we trust"

no way. cant run it on an m45, anyway. you MIGHT be able to machine down the snout a bit further than i did and maybe take more off the pulley i did to POSSIBLY squeeze a 2.35 on it but thats the absolute max. the m62 however has the pulley ran on the outside edge of the snout, it doesnt ride over it like the m45. at least on my m62 it doesnt anyway so yes, in theory you could run a pulley the size of the shaft if you wanted to LOL.

but lets be realistic here, a 1.9" pulley is not going to produce you any results man. its going overspin that blower WAY WAY WAY over its redline and not give you jack for results. there comes a point where going smaller on the pulley just doesnt do anything. and believe me, im all for overspinning the blower and trying things out to see but im telling you, its not going to work out. the lowest ive ever heard of anybody putting on even a gen 5 m62 is a 2.6 iirc and that was even unbelievable to most lol

RIP silver car. You will be missed.

but lets be realistic here, a 1.9" pulley is not going to produce you any results man. its going overspin that blower WAY WAY WAY over its redline and not give you jack for results. there comes a point where going smaller on the pulley just doesnt do anything. and believe me, im all for overspinning the blower and trying things out to see but im telling you, its not going to work out. the lowest ive ever heard of anybody putting on even a gen 5 m62 is a 2.6 iirc and that was even unbelievable to most lol

RIP silver car. You will be missed.

Pulley boys recomends a 2.2 for my blower to make 10-13 psi and i want more than that so thats why i was thinking 1.9 with a massive air to air intercooler and hope i could keep the heat down to benifit from it but if i cant i guess 2.2 will have to do you guys have all been running blowers im still learning all my motors ive built have been n/a 4.3s and sbc so i will have fath in your wisdom and run the 2.2 i wanna make power efficiently thats for sure

I Love My J ♡

I Love My J ♡

dont just slap on the tiniest pulley on your blower............................................................

thats asking for ridiculous belt slip, instead find an over sized crank pulley so you have more surface area for the belt to ride on as the belt might ride on 1/2 of the pulley so 1.9 is only say 1" of pulley when you can say make a 3" pulley and over sized crank have the same boost but now have 1.5" of contact and this way you wont have as much chance for belt slippage

thats asking for ridiculous belt slip, instead find an over sized crank pulley so you have more surface area for the belt to ride on as the belt might ride on 1/2 of the pulley so 1.9 is only say 1" of pulley when you can say make a 3" pulley and over sized crank have the same boost but now have 1.5" of contact and this way you wont have as much chance for belt slippage

Learn how to read compressor maps and you'll understand where everyone is coming from. Every turbo or supercharger has an efficient range. Spinning it above that just creates heat or the flow is maxed out and you choke the engine.

Don't take any offense to this but:

You need to slow down and learn and UNDERSTAND what unit you have. Understanding what CFM it flows, what RPM's it runs at efficiently, where its choke point is etc is going to determine your pulley size.

But guess what - you have to work backwards from your crank pulley size to do this. Once you work out the crank pulley's relation to the supercharger pulley you'll see where you're at.

2 things to note:

I forget the name of the map (somebody else may remember but I found one during my search for G-Lader information) they make maps that chart how much heat is made at what RPM and where the heat overcomes the benefits of compressing the air. i.e they'll say the blower can make 540 cfm but at the 500 cfm mark the heat was almost negating the gains in volume and it would be better to spin the charger a bit slower. This is hugely important and I've seen them for M62's and M90's on the internet. You'll need to understand this function of a supercharger (and more importantly your exact unit) to do your calculations.

Compressors aren't rated by how heavily they can compress the air - i.e PSI ability. They are rated by their flow rate - how much air they can literally flow through themselves. I would much rather flow 600 cfm at 3 psi than 300 cfm at 30 psi... flow = HP. PSI = pressure against the engine and its internals. Guess which one is better.

Once you are armed with ALL that information, understand what RPM you'll be spinning the charger at creating what CFM... THEN you can start to decide what pulley size you need to / want to run on it.

Like I said - slow down. Listen to the advice you are getting... learn and understand that exact M62 model fully.

You'd be shocked but bolting a compressor to an engine is about 10% of the difficulty factor. A lot has to go into belt design due to belt slip/torque and even more has to go into understanding the compressor itself and its effects on the engine it will be pumping air into.

The people that strap a S/C to their engine and are either "shocked" or "disappointed" with the results on a dyno didn't do their engineering homework to understand the compressor and what it could do. ANY well engineered project comes within an acceptable % of expected gains due to proper calculations, preparation, design & tuning.

Engines = math my friend... and you have a lot of math homework to do.

With that said I'm watching this thread with rapt interest.

-Chris-

**-Sweetness-**

**-Turbocharged-**

**Slowly but surely may some day win this race...**

You need to slow down and learn and UNDERSTAND what unit you have. Understanding what CFM it flows, what RPM's it runs at efficiently, where its choke point is etc is going to determine your pulley size.

But guess what - you have to work backwards from your crank pulley size to do this. Once you work out the crank pulley's relation to the supercharger pulley you'll see where you're at.

2 things to note:

I forget the name of the map (somebody else may remember but I found one during my search for G-Lader information) they make maps that chart how much heat is made at what RPM and where the heat overcomes the benefits of compressing the air. i.e they'll say the blower can make 540 cfm but at the 500 cfm mark the heat was almost negating the gains in volume and it would be better to spin the charger a bit slower. This is hugely important and I've seen them for M62's and M90's on the internet. You'll need to understand this function of a supercharger (and more importantly your exact unit) to do your calculations.

Compressors aren't rated by how heavily they can compress the air - i.e PSI ability. They are rated by their flow rate - how much air they can literally flow through themselves. I would much rather flow 600 cfm at 3 psi than 300 cfm at 30 psi... flow = HP. PSI = pressure against the engine and its internals. Guess which one is better.

Once you are armed with ALL that information, understand what RPM you'll be spinning the charger at creating what CFM... THEN you can start to decide what pulley size you need to / want to run on it.

Like I said - slow down. Listen to the advice you are getting... learn and understand that exact M62 model fully.

You'd be shocked but bolting a compressor to an engine is about 10% of the difficulty factor. A lot has to go into belt design due to belt slip/torque and even more has to go into understanding the compressor itself and its effects on the engine it will be pumping air into.

The people that strap a S/C to their engine and are either "shocked" or "disappointed" with the results on a dyno didn't do their engineering homework to understand the compressor and what it could do. ANY well engineered project comes within an acceptable % of expected gains due to proper calculations, preparation, design & tuning.

Engines = math my friend... and you have a lot of math homework to do.

With that said I'm watching this thread with rapt interest.

-Chris-

Sweetness, I think the chart you're thinking of is the adiabatic efficiency chart.

There definitely is a ton of math that goes into engine design. I've done more reading and number crunching than I'd like to admit and that's all just been n/a building.

Boost is another whole topic that builds on the principles of n/a engine building. I'm not nearly as versed on it as I wish I was.

There definitely is a ton of math that goes into engine design. I've done more reading and number crunching than I'd like to admit and that's all just been n/a building.

Boost is another whole topic that builds on the principles of n/a engine building. I'm not nearly as versed on it as I wish I was.

Brian wrote:

Learn how to read compressor maps and you'll understand where everyone is coming from. Every turbo or supercharger has an efficient range. Spinning it above that just creates heat or the flow is maxed out and you choke the engine.

yes.. BUT, you increase efficiency by cooling the charged air off drastically by using meth/water injection. so this is how you can get away with spinning an eaton way past its redline and still make power. as far as flow goes, porting it will help with that. i can see using a 2.6 or 2.7 or an m62 but NEVER a 1.9. not with our crank pulley diameters, anyway.

cody, they actually recommend you use a 2.2" pulley on an m62? did they assume the crank pulley was 5" or something? LOL

Edited 1 time(s). Last edited Tuesday, September 03, 2013 4:12 PM

RIP silver car. You will be missed.

I'll just remember that we agree to disagree on meth Brad. Haha.

Took no offence to any of that and thanks for the detailed advice ill admit i have no idea what the limits are of my m62 i havnt looked into thst near as much as i want to or need to i just got excited because i started getting some money togeather to get this in gear finall. I need to find out what cfm it will flow what the rpms limit is get ahold of md on his pulley size and figure ouy the formula on the rpms ill be spinning with what size pulleys and at what engine rpm and how much boost ill be making at that rpm so i know where i am at i do have alot of math in my near future but all in the search for power igot the engine build figured out that was easy for me but this boost part is new to me so ill admit i do need to breath for a second and stand back and look at whats going on and plan carefuly i only wanna do all this once and i have decided to go remote mount too ive made my mind up on the whole build finally so now its math and even more research soo exciting any help you guys can offer my ears are open you guys know and i dont. At this point im going all out i wanna get as much whp as posible with what ive got blower wise and with the ld9. I have fath in the end i will be impressed with the results so here we go haha oh btw if anybody knows the math formulas i need or where to find graphs and blower spacific info i need any help would be awsome to cut back on my search time

I Love My J ♡

I Love My J ♡

Brian wrote:

I'll just remember that we agree to disagree on meth Brad. Haha.

meth all the things! lmao

RIP silver car. You will be missed.

nobby, to calculate blower rpm use this equation:

crank pulley / SC pulley = x

x * RPM = SCRPM

mike's oversized crank pulley is 7". so, lets use that and assume you'll be using stock 6500 reline with your 1.9" snout pulley just for shiz and gigs...

7" / 1.9" = 3.68

3.68 x 6500 =**23,920 rpm**

ive heard the gen five cobalt ss m62 redline is 16,000. so, a less efficient, older gen 3 model spinning 23,920 rpm. see where i am going with this?

RIP silver car. You will be missed.

crank pulley / SC pulley = x

x * RPM = SCRPM

mike's oversized crank pulley is 7". so, lets use that and assume you'll be using stock 6500 reline with your 1.9" snout pulley just for shiz and gigs...

7" / 1.9" = 3.68

3.68 x 6500 =

ive heard the gen five cobalt ss m62 redline is 16,000. so, a less efficient, older gen 3 model spinning 23,920 rpm. see where i am going with this?

RIP silver car. You will be missed.

Doing some really fast research for you:

Eaton Supercharger Data

That page shows that if you have a gen 3 model your recommended redline on the charger from Eaton is 14,000 rpm. That solves that question.

Here is a flow chart for the 3rd gen M62:

That chart was found here

Where he is trying to plot it against a Gen 5.

A little bit more digging on google and I found this site

Showing these 2 bonus maps for the M62:

Power Consumption

Delta T

Delta T is the change in the intake air temp after it is compressed.

Delta T= Intake Absolute Temperature x (Pressure Ratio to the .238 power –1)/ Compressor Efficiency

Lets assume our engine is going to run 20 psi of boost or a pressure ratio of 2.36.

Pressure ratio= boost pressure+14.7/14.7

The temperature scale engineers use for absolute temperature is the Rankin Scale. On the Rankin Scale Zero degrees is absolute zero. So assuming our intake air temp is 85 degrees, lets call that 545 degrees Rankin.

Lets say our match car is a hot Acura GSR with a B18C motor. By using standard compressor matching equations , we figure that the B18C can flow about 45.3 lb/min going full tilt at 20 psi.

So here we go. Lets figure out Delta T for our good turbo first. Lets assume an efficiency of 78% as there are many turbos that can do that at the given flow and pressure ratio.

Delta T= 545 x (2.36 to the .238 power –1)/ 0.78

Delta T= 158 degrees

A 4-cylinder sized Centrifugal Supercharger is probably much less than 70% efficient at this point but lets be kind to it and assume that, Plugging and chugging gets us a temp of 177 degrees.

(The above was found on this site in post # 5 showing even more calculations you can make to plot your supercharger against your engine.)

There - I just did a crap ton of research for you... now it's up to you to sit down and figure out all the math and work it out against your engine so you can determine your power goals, pulley size, etc.

BEFORE you jump in Brad and start going off on meth and intercooling and porting YES you can add all that to the mix BUT bear this in mind:

- Meth & Intercooling affect the DELTA T because they cool the compressed air charge down, upping efficiency. You can recalculate that if you can figure out just how much it will cool the charge air down and what & the efficiency will increase.

- Porting changes the volume of the supercharger (litres of air pumped into the engine per revolution of the supercharger) which changes CFM but not Delta T nor the adiabatic efficiency. (Thanks for the reminder on the term, Brian!)

- No matter what in your calculations you need to work out how much HP the supercharger will require to turn at your desired max RPM... this will have to be factored in against your expected power gains.

Hopefully I've given you a lot to think about, Cody.

-Chris-

**-Sweetness-**

**-Turbocharged-**

**Slowly but surely may some day win this race...**

Eaton Supercharger Data

That page shows that if you have a gen 3 model your recommended redline on the charger from Eaton is 14,000 rpm. That solves that question.

Here is a flow chart for the 3rd gen M62:

That chart was found here

Where he is trying to plot it against a Gen 5.

A little bit more digging on google and I found this site

Showing these 2 bonus maps for the M62:

Power Consumption

Delta T

Delta T is the change in the intake air temp after it is compressed.

Delta T= Intake Absolute Temperature x (Pressure Ratio to the .238 power –1)/ Compressor Efficiency

Lets assume our engine is going to run 20 psi of boost or a pressure ratio of 2.36.

Pressure ratio= boost pressure+14.7/14.7

The temperature scale engineers use for absolute temperature is the Rankin Scale. On the Rankin Scale Zero degrees is absolute zero. So assuming our intake air temp is 85 degrees, lets call that 545 degrees Rankin.

Lets say our match car is a hot Acura GSR with a B18C motor. By using standard compressor matching equations , we figure that the B18C can flow about 45.3 lb/min going full tilt at 20 psi.

So here we go. Lets figure out Delta T for our good turbo first. Lets assume an efficiency of 78% as there are many turbos that can do that at the given flow and pressure ratio.

Delta T= 545 x (2.36 to the .238 power –1)/ 0.78

Delta T= 158 degrees

A 4-cylinder sized Centrifugal Supercharger is probably much less than 70% efficient at this point but lets be kind to it and assume that, Plugging and chugging gets us a temp of 177 degrees.

(The above was found on this site in post # 5 showing even more calculations you can make to plot your supercharger against your engine.)

There - I just did a crap ton of research for you... now it's up to you to sit down and figure out all the math and work it out against your engine so you can determine your power goals, pulley size, etc.

BEFORE you jump in Brad and start going off on meth and intercooling and porting YES you can add all that to the mix BUT bear this in mind:

- Meth & Intercooling affect the DELTA T because they cool the compressed air charge down, upping efficiency. You can recalculate that if you can figure out just how much it will cool the charge air down and what & the efficiency will increase.

- Porting changes the volume of the supercharger (litres of air pumped into the engine per revolution of the supercharger) which changes CFM but not Delta T nor the adiabatic efficiency. (Thanks for the reminder on the term, Brian!)

- No matter what in your calculations you need to work out how much HP the supercharger will require to turn at your desired max RPM... this will have to be factored in against your expected power gains.

Hopefully I've given you a lot to think about, Cody.

-Chris-

Also because I feel generous for some reason this afternoon let me assist you a bit:

Stock crank pulley size is 6.406 inches (courtesy of MD-LD9)

We already know that the blower maxes out at 14,000 rpm so working backwards we need a crank pulley to supercharger pulley ratio of 2.153 MAX... let's plot that at 6500 rpm:

14,000/6500 = 2.153

6.406/2.153 = 2.975"

**Therefore you need a 3.0" pulley to max out the supercharger at 6500 rpm with a stock crank pulley.**

Let's look at the Unorthodox Racing Underdrive Pulley for comparison:

UR crank pulley size = 4.482 inches (courtesy of MD-LD9)

4.482/2.153= 2.08"

**Therefore you need a 2.08" pulley to max out the supercharger at 6500 rpm with a Unorthodox Racing crank pulley.**

So a 2.1" S/C pulley on a UR Crank pulley would yield:

4.482" / 2.1" = 2.1342

2.1342 x 6500 =**13,932 rpm**

And a 3.0" S/C pulley on a UR Crank pulley would yield:

6.406" / 3.0" = 2.1353

2.1353 x 6500 =**13,879 rpm**

All that is done with an expected redline of 6500 rpm. The higher your max rpm the bigger your S/C pulley has to get to keep it under its limit.

Like I said - engines are math.

-Chris-

**-Sweetness-**

**-Turbocharged-**

**Slowly but surely may some day win this race...**

Stock crank pulley size is 6.406 inches (courtesy of MD-LD9)

We already know that the blower maxes out at 14,000 rpm so working backwards we need a crank pulley to supercharger pulley ratio of 2.153 MAX... let's plot that at 6500 rpm:

14,000/6500 = 2.153

6.406/2.153 = 2.975"

Let's look at the Unorthodox Racing Underdrive Pulley for comparison:

UR crank pulley size = 4.482 inches (courtesy of MD-LD9)

4.482/2.153= 2.08"

So a 2.1" S/C pulley on a UR Crank pulley would yield:

4.482" / 2.1" = 2.1342

2.1342 x 6500 =

And a 3.0" S/C pulley on a UR Crank pulley would yield:

6.406" / 3.0" = 2.1353

2.1353 x 6500 =

All that is done with an expected redline of 6500 rpm. The higher your max rpm the bigger your S/C pulley has to get to keep it under its limit.

Like I said - engines are math.

-Chris-

Sorry to correct the verbage in the last calculation:

And a 3.0" S/C pulley on a**STOCK** Crank pulley would yield:

6.406" / 3.0" = 2.1353

2.1353 x 6500 =**13,879 rpm**

-Chris-

**-Sweetness-**

**-Turbocharged-**

**Slowly but surely may some day win this race...**

And a 3.0" S/C pulley on a

6.406" / 3.0" = 2.1353

2.1353 x 6500 =

-Chris-

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