supercharger for 6.2?

[jbell]

This is a "is this doable post?"

Use a cheap (200-300 rebuilt) supercharger designed for a 3.8gm motor. Custom make intake flange/bracket and bolt it to the top of the intake. Add multigroove pully to front of crank / route belt to supercharger. Tie the internal bypass valve to the throttle linkage, so that more throttle results in more boost. This would probably be a low psi install (max 4 psi or so...)depending on the pully sizes -- but would result in nice cool pressurized air without an intercooler... AND I could keep my A/C...

Thoughts anyone?

[Peter J. Bierman]

Try and you know if it works.
Would be cool anyway :cool:

Peter

[Craig M]

Do a google search on supercharger. A couple of guys have installed superchargers on the Hummer H1. The H1 has the 6.2 diesel. They wanted more power and the superchargers were their answer. Their descriptions might help you.

[jbell]

All I find is H2 supercharger kits. No H1 stuff with the diesel. Any links?

Been measuring, looks like the supercharger nose could go slighty driver side offset -- move the powersteering resevoir, and use the middle powersteering v belt. Also have to change to vbelt pully on supercharger.

[whatnot]

If you wanted to buy a bolt on unit, tese people make them: http://www.marinedieselusa.com
I bet they are a lot more than a Banks turbo kit.

If you could make a 3800 supercharger work, It should be much cheaper.

Why would it be cool air? Most of the intake air heat in a turbo engine comes from the air being compressed. They still use intercoolers with superchargers because the same thing happens.

[Craig M]

There are no kits that I am aware of. There are a couple of writeup by individuals that have installed superchargers on their personal H1's. I forget where I read them, but I know it has been done more than once. The Banks set up is of course is a turbocharger, not a supercharger.

[grape]

at 4 pounds it may take more power to drive the thing than it can make.

[henryj]

How much boost can you get from that thing? I thought that a supercharger was impractical on a 6.2L due to the high compression ratios that they produce. If anyone knows different please point me in the right direction.

[jbell]

On a t-bird supercoup, a eaton m90 makes 15psi, but you are correct, it takes (I've heard, still verifying) about 15 - 20 hp to make that amount of boost. The more boost, the more hp it takes. With the bypass valve open, it takes 1.5 hp. You are also correct, a positive displacement blower genereates heat, just not as much as a centrifugal blower (turbo) does. @10psi, a m90 generates 75degree delta T. What I'm still researching is the hp required / psi of boost to make sure that 4psi allows me to make more hp than I'm using to run the supercharger.
--more later

[britannic]

Think of this, the conversion of fuel into energy in an IC engine is approximately:

33% crankshaft power
33% wasted heat
33% exhaust heat

A supercharger will need to take some of that 33% of crankshaft power, before the additional energy is extracted when more fuel is added.

A turbo however, taps the 33% exhaust energy and a small amount of wasted heat, without taking much from the crankshaft (backpressure in the turbo will take a little - depending on it's efficiency range). Adding a turbo can increase the diesel's efficiency to around 55%.

A blower is very useful on gassers, because they can compensate for the lack of low rpm torque.

IMHO, a turbo is the easiest retrofit on our diesels. Of course, a blower/turbo combo would be even sweeter :D .

[JeepSJ]

Originally posted by britannic:
IMHO, a turbo is the easiest retrofit on our diesels. Of course, a blower/turbo combo would be even sweeter :D . TE06H blowing into a supercharger? That would most certainly push out the head gaskets or drop the crank out of the block. That would be very cool on a Cummins - ooohhh...a turbo/supercharged 4bt in my CJ. That 3800 supercharger would be just about right on a 3.9L Cummins. I now know what my next project will be. Right after I finish the Wagoneer, finish my daughter's bedroom, finish the remodel on the master bathroom, fix the water leak in the basement, etc...

[ 05-04-2004, 05:02 PM: Message edited by: JeepSJ ]

[EWC]

The kit you are thinking of was from Whipple Industries and was for the Hummer H1 with the 6.2 . Unfortunately that kit is not shown in their current listings . I had some info for the kit and the price was $5000 about 5 years ago . The supercharger used was of the screw type and not the Roots style that is mentioned .

[jbell]

http://www.wastewaterdepot.com/roots_performance.html

Hey check this out!! These things don't take as much hp as I feared. I know this is not the gm3800 roots, but this give me an idea of what kind of numbers to expect....

[jbell]

http://www.magnusonproducts.com/mp62.htm

OK.... Here's my math, help me out if I'm wrong.
On a 6.2 liter engine @2500 rpm, it takes 273cfm.
To get 273cfm@5psi on an eaton62 (the gm3800 supercharger) It takes 9000 supercharger rpm. Which requires 10hp, and has a delta T of about 100 degrees above ambiant. The question is.... @5psi, how much more fuel can I burn, and how much additional hp / torque can I expect to get in return? Keep in mind that I will have the bypass valve connected to the throttle, so that it'll only be making this much boost when I'm being heavy footed. When the bypass valve is open, it only consumes 1.5 hp and makes little boost. I figure 1.5hp is a small trade off on flatland cruising to have hill climbing power when I need it.

someone check my math on the cfm... I did 2500rpm / 60 = 41.67rps. 41.67rps * 3.1 liters/rev = 129.17 liters/second. 129.17lps * conversion factor 2.1189 = 273cfm. I used 3.1 liters, as an intake stroke is only every other rev. Did I do it right?

And yes... the output temp is high... for continuous boost, it'd need an intercooler.

[jbell]

anyone check my math to see if it is accurate? Anyone inject/vaporize water to lower intake temps?

[grape]

I'll do the math later when i have my formulas in front of me, but what's the point of flowing the same amount of air the engine uses to produce 150hp naturally aspirated through a blower at 5lbs. Your gonna make the same power with the same amount of cfm. Gotta cram more through it. If that blower only moves that amount of air at 5lbs it's gonna be a huge restriction in the lower rpms.

[grape]

in simplified fashion try this formula

(cid x rpm) / 3456 = CFM

this formula is for a 100% efficient engine so you have to multiply the CFM by say 90% to get actual flow.

CFM x .069 to get pounds per minute found on turbo maps, gas engines take 10 pounds for every 100 horsepower, diesels take 10 pounds to make 80 horspower.

so then you can go backwards and figure if the engine is 100% efficient at 2500 you will use 18.91 pounds of air per minute with total possible power output being a little over 151hp at 2500 rpm.

But the purpose of super or turbocharging is to cram more volume of air in the engine than it displaces by itself.

[ 05-11-2004, 12:06 PM: Message edited by: grape ]

[jbell]

so, if atmospheric is 14.7, and I run positive 5psi, that's 1/3rd more air than NA. So I should be able (minus my supercharger requirements) to make 1/3 more hp.

So... A 155hp 'j' code motor, can add roughly 50hp, minus 12hp to run supercharger for a net add of 38. And you're right, I need to add 1/3 to my cfm figure as well, so that would be 363 cfm @5psi -- right?

To make 363cfm @5psi requires 11,000 supercharger rpm @ 12 hp.

[grape]

you've just figured out what most never will.

[jbell]

OK, everything makes sense on the hp / cfm figures.
How do I figure out how much additional torque I will generate? Is it a 1/3rd higher as well? A j code motor is 280ft.lbs, so will I get +93ft.lbs more?

[CleviteKid]

Horsepower = torque(ft-lb) x rpm / 5250.


So 1 hp = 1 ft-lb of torque, but only at 5250 rpm.

At half that rpm, i.e. 2625 rpm, 1 hp requires 2 ft-lb. of torque to produce the power.

So if you are making 50 extra HP at 2625 rpm, you are also making 100 extra ft-lb. of torque.

If you wanna be a REAL gearhead, you will memorize this formula, like I did decades ago. You can use it to check published torque and horsepower curves. If the values of hp and torque are not EXACTLY EQUAL at 5250 rpm, someone is lying to you. And at ANY rpm you want to pick off the curves, the above equation has to be true or something is wrong with the data.

Dr. Lee

:cool:

[grape]

that's exactly what puzzels me on the peninsular site with the dyno sheet along with marine diesel usa's website..........something doesn't jive.

[grape]

has anybody else noticed the math was off on those dyno graphs?

[Ratau]

Jbell

Did you come to a final conclusion on this topic? Please let us know.

Danie

[jbell]

Here's my conclusion: I'm going to see exactly how far I can get normally aspirated first. I'm currently swapping in a '89 700r4 from a rusted out 6.2 suburban to get OD. (TH400 -- 4.1 gears, and 32" tires is painful on the ears / rpms.) I don't trust a 700r4 (never have -- went through 6 of them on a s-10 in the early 80's.) so I'm putting on a 6" th350 tailhousing / 1350 yoke so that my 2WD drive shaft only needs shortening by 3/4". If the 700r4 goes down, the th400 is going back in and 3.42 gears are being installed. The going hot rod wisdom says that a th400 takes 13 more HP to operate than either a th350 or 700r4, so just changing tranny's should net me a little HP gain to the rear wheels. After that, the exhaust is getting worked on, then a SAA intake / pump turn up. If I'm happy, I'll stop there, If not, the 3.8supercharger is going in. However at 14degrees per psi (that's typical temp rise on a roots supercharger), I'm not going crazy on boost. about 3 - 5psi is as far as I'll go without an intercooler. Going from NA at a slight vacuum to even plus 1 psi will yield a reasonable improvement in VE and HP/torque -- I might start there. The statement "More than one 6.2 has bitten the dust due to too much HP -- is still ringing in my ears...." and I have the factory 21.something pistons. The eaton m62 from the gm3.8 has plenty of capacity to feed a 6.2, the t-bird supercoup m90 is overkill, and less efficient. I'm sure this isn't the last of this conversation.......

[jbell]

http://www.lordlife.com/images/Picture%20233a.JPG

WOW!! what a difference a transmision makes. TH400 to 700r4, with 4.10 gears is an AWESOME combination. My burb now accelerates faster than my 193hp tacoma, and is quite possibly faster than my wife's 200hp escape!! (Can't get her to race me.... yet....) It is amazing how fast I can 0-85. Took three attempts before I was happy with the tv cable, but now it shifts perfect. (well it was from a diesel 1/2 ton burb, so it should) The most amazing thing is the noise level is 1/2 or less of what it was with the th400, now that my rpm's are out of the stratosphere. It's no louder than the tacoma, and since the tacoma has an awesome stereo..... I'm thinking custom center console, with earthquake subwoofer, rear seat ac vents, lcd / computer / dvd, etc...

I'm so glad I started with a "j" code 3/4 ton, with the 14 bolt rear, etc.. and changed 'down' to a 700r4. Very easy place to start the modifications.

I'm seriously reconsidering the supercharger -- not sure I need it. However if I do, I'll also do water spray using collected condensate from the a/c, that operates any time the supercharger bypass valve is closed to keep intake temps cool, and add even more power. (here in the humid midwest, the ac provides more than enough water for spray.)

Right now, I need to get digital egt gage, trans temp, and tiny tach. That way I can baseline my current config before doing any more modifications. I'll keep updating this thread with my future modifications as they come.

[jbell]

Ok, I admit... I need more power. Coming back from chicago, against a 30knot or better headwind, my father-in-law (In a 4 cylinder intrepid) decided that he needed to follow me -- so he wouldn't wory about losing me back in traffic.... Talk about embarassing.
I have plenty of fuel on tap, just can't use it -- I need more AIR!!!

[Peter J. Bierman]

TURBO!!!

Mmmmm, yes you defenitly need a turbo ( or 2 ) :D

Peter

[Peter J. Bierman]

Sorry, a mech. blower will do the trick also.

Peter

[RaptorMan555]

Hey Jbell

I like all this I'm reading about the supercharging but its beyond me. HOpe it all works out. Do u still have the vacumm lines for the th400? I f so let me know OK? Thanks

[jbell]

yep, got the th400, the flexplate, and the vacuum line.