Stavros

Will that be harmful (or a serious strain) on the crank or crank bearings?

Im thinking it could be, more strain in the same way a long bar makes undoing a bolt LOADS easier...

But im sure ive seen cars with long extensions off the crank to run a supercharger.

Basically its for the S13, been fitting stuff tonight and the only way i can make it all work how i want is to add a 5inch or so nose extension to the end of the crank pulley to line it up with the s/c one.

I know its pretty unlikely that people on here have much experience of shit like this, but im hoping someone does

bud-weis

i don't think it'd be too much bother as long as it's not way out of balance or owt??

boXXer

if it was ally, i dont think it would be a problem as it wouldnt weigh too much. Only other thing could be too much belt tension maybe?

Stavros

hmm, now i think, the only extensions ive seen are to the supercharger nose, not the crank nose.

SO this could mean 2 things.

A)- Most installs dont have this issue so u dont see it.

B)- Its SUCH a bad idea and will fuck the crank that nobody does it.

boXXer

is there that much tension on the belts then? didnt think they were that tight? only place it would really put extra load onto is the first bearing maybe?

Stavros

Well on multi-v belts like most modern s/c installs use the belt is MEGA tight.

It has to be, superchargers often take 50bhp+ (depending on car n s/c, 200+ on big power motors) to turn them at full wack, so will slip like fuck unless super tight.

Im gonna run a toothed belt, but the power issue is still there, n worried
"something" (if im honest i dont know what, otherwise id not ask ) to do with this will cause harm.

boXXer

i assumed you meant it would be toothed. Could you use a cambelt of some sort? If so, you wouldnt need much tension at all really as long as it didnt slip.

Stavros

Yes, the belt used is similar to a cambelt.

And yes, wont need to be mega tension, but a decent amount still.

Tho a s/c takes a LOT more force to run than cams id guess, so still pretty bloody tight, esp as it needs to cope with rapid rpm changes, like downshifts, etc etc.

And im not sure if its just tightness that will be the issue, hmm.

boXXer

i always thought Superchargers were quite free running (like turbos), but ive never played with one so wouldnt know.

If you think about how hard the rod gets thrown down on ignition stroke, i dont reckon a S/C would be more load than that on the bearings would it? just guessing really.

Stavros

Yeah, your prob right TBH with regard to the rod thing.

Turbos take power to run em too, no such thing as free energy, just people dont think about it, and it dont directly affect another engine component, so its less important.

A turbo is free running when there no pressure acting against them, but imagine how much force it takes to rotate something at 100,000rpm when there is 30psi of pressure acting against it!?!

A 7500bhp top fuel dragster running a supercharger to 12,500rpm (engine speed 8500rpm) and running 45psi boost, the supercharger consumes 900bhp to turn it like that

So if there was some way of magically giving the engine that much airflow/boost without the engine doing it at all (so no turbo or supercharger) the thing could push more like 8500bhp...

boXXer

yeah see what ya mean. I assumed a S/C just compressed air with the blades, not having much to push back against them, and not consume much power, especially to compress to smaller levels compared to turbo's.

But i did know about the drag thing, as a pit crew man @ Santa pod told me.

Garage19

I would machine up some kind of out rigger bearing.

Its not so much the weight of the extension as the leverage it can exert over the last main bearing.

GARETH T

i wouldnt like to run a extension piece that big on my crank!

i think it would be hard to run a bearing on the end of it aswell, as it would have to be mounted to the engine some how

steve stick a liny turbo on it

Fudgey

iTrader: (4)

go with dougs idea, but use an extension on the chager with an extra bearing somehow...

that would be my choice as the SC will cheaper/easier to replace if it goes tits up lol

MAD matt-sab

the other point worth considering worth be an extension as described but but a roller bearing support on the end of it so the weight and pressure is not all on the already not so strong crank bearings.
but yes this is not an easy fix or job and tears my be caused by this 1
good luck with it and keep us posted steve.

boXXer

try it and see how long it lasts.

Big Will_

Stav - drop Chris@TorqueOfTheDevil a PM mate - he's supercharged more things than most...

And a lot of those were "This can't possibly work..." at the outset

Stavros

Ive no idea what you mean by an out rigger bearing?!

But yeah, i know its not weight, its leverage, like i said, dont seem wise to me.

But i cant see another option

Mark Shead

The 800hp boat engine I had on the dyno last week had one of these but it was killing the belt over 5000rpm, and the 1500hp drag car I did today has a belt about 3inch's wide and this had no problems.

Mark

DROPTOP

leave the turbo's and s chargers and run compressed air tanks in the boot with pressure regs/air injectors to a sealed inlet

id go with an extra bearing and toothed belt

Stavros

MArk- It had an extension on the crank? Not the charger?

What does everyone mean by an extra bearing? where

Ill run a toothed belt.the chargers only a smallish one good for under 250horse, shouldnt be a mega strain, usually cope well being powered by a inch wide non-tooth belt, so the wider toothed one i got wont be the problem.

But a long crank nose fucking the big ends is

But aside from this solution, the other options are a severe pain in the arse, but i got 99% of the bits now and the car will run shit with turbo alone, so needs to be sorted, and its interesting, which is prob most the reason im doing it...

Big Will_

Stav - run your supercharger off a driveshaft

Mark Shead

The boat had a massive alloy spacer on the crank to space the drive pully out from the engine it was at least 5inch but more like 6inch.

Mark

Big Will_

Mark Shead - I know Steve asked this question earlier - but do you know if using a belt that far from the supported end of the crank applies a greater load onto the bearing shells/oil seals etc.?

Have you seen any complications from this sort of setup?

Cheers

Mark V8

iTrader: (2)

Outrigger bearing on a bike engine output shaft but you get the idea


Mark

Mark Shead

I cant say how long the boat lasted but these engines need to be reliable as they are held at full throttle for long periods of time.

Mark

DROPTOP

===:::::P::::B

=== crank
:::: extension
P pulley
B bearing

proper engineering drawing

Stavros

So this design people are saying is running it from a different pulley that itself is ran from the crank?

Obviously this wont directly mean the extension is on the crank, but it means the crank is powering an extra pulley and still not using any less force to turn the charger, surely?
Cant see it being a huge help, and one things for sure, will complicate matters, so im kinda not convinced, unless im missing something?

Thanks to Marks good info, it seems its done at least, so maybe its just worth a try?

I mean, a complete decent CA bottomend is 100quid, a set of bearings is 50odd (i have a spare set), and hell, i got a complete spare engine.

Does kinda seem its worth a punt to see what happens, all in the name of research like, lol.

One good thing is the crank isnt powering the heavy viscous fan or power steering pump anymore at least.

If anyone has pics of other engines using a similar extension, thatd be fookin cool

DROPTOP

no , the pulley is on the crank but with a supporting bearing at the end of the extension . could run it to a seperately mounted pulley then on to the charger but more fab work . although doing it that way you might beable to sort pulley sizes to put less load on the engine

Stavros

Oh right, i think, possibly, i get you.

Trouble is i cant have another support at end of extension, radiator will be in the way

focusv8

Yes a 5 1/2" extension will put a serious strain on the crank.
Exactly twice as much strain as a 2 3/4 " extension.
Enough to snap the crank? Depends how much boost you are trying to get from the S/C.

My Vortec S/C when fitted to My Mustang 5.0 with a kit supplied by Vortec used an extended pulley of about 4 1/4 ".
The standard pulley for Alt, P/s etc is about 2 1/4"

Is the extension to allow the belt to miss something, or is it just to match up to the Supercharger pulley.

If it's the second, it will be easier, safer, more reliable, and possibly even cheaper to get the S/C altered to match a Crank pulley with little extension.

If it's the first, you need an outrigger bearing assembly, but that needs to be well engineered and correctly aligned when fitted or it will be a waste of time and money.

My Vortec now in my Focus, driven off the main crank pulley;
http://img.photobucket.com/albums/06...n/IMG_0272.jpg

.
.

DROPTOP

shove it forward . if not then go for the second pulley , use brackets etc from the redundant pas ? or fit the pas pump and belt but dont connect it to the rack then weld a pulley on the end of that to run the charger (providing the pas bearings dont need lubrication from the fluid)

Stavros

It needs it as the only place the supercharger will fit moves it too far forweard of the engine

Other option is turn supercharger other way round, but will need a custom 3/4 width radiator and some gay bendy boost piping.

DROPTOP

might be easier though

DROPTOP

remember it needs to spin the right way though lol

Stavros

ah shit

DROPTOP

whats it run as standard? what do you want it for? just something to kill or to use day to day?

AlexF

why cant you mount the S/C nearer the crank?

aolex

focusv8

You can get toothed belts with teeth on both sides of the belt, so you would get reversed direction on one side.

.

GARETH T

i still dont like the idea of having an extension the crank,,