4k Superchargeing

[kickn5k]

Hi,

Kickn5K Just curious did you happen to use my how to fit a sigma aircon pulley to a SC12/14 blower article on here? As I have a SC14 with that pulley I used on that post on my blower if yours is the same pulley that is what I can expect then.

Also my sigma pulley has 2 belt grooves for a V belt does yours?

Cheers

Cameron

No sorry i didnt get a chance to read that, but will now. I turned the back pulley off to get a better spacing, then i ground out the 3 rivets on the sc/12 clutch bit with the spline in it. Drilled and tapped the sigma pulley and bolted it all up. so now i only have 1 pulley on it. Ill be making an alum one as soon as i can find a suitable peice of billet.

 

stu.

Edited October 28, 2008 by kickn5k

[kickn5k]

what u mean vented out after 2 laps?

shouldnt it vent on deceleration? throttle closed?

elaborate i don't get what ya mean lol

and yeah i can't wait for the silly grin on my face when i finally have a boosted corolla haha

 

Its sort of fixed i have plumbed it back into the inlet of the sc it stops the hiss at idle but its still reasonably loudish but at least its plumbed back.

I havent had a chance to measure my pulley setup yet. But have been thinking if its used on a 4k being less in capacity it will probably make more than the 5psi I'm making maybe about 8 i think. I have also found the spare rib belt pulley welded to the early 4k balancer that came with all the bits i bought ill measure the vbelt pulley size but the ribbed pulley is quite small so it may work for you. If you can use it pay for the postage c.o.d and its yours.

 

stu.

[DearmanKE]

cool man, take some pics n ill let you know.

also could u get a measurement of it?

cheers

-Alex

[5kpanelvan]

setup was not done by me it was done by local carby place in melb and I'm not to sure on size of su ill try find out for you

 

 

 

ps engine is very dirty lmao

[philbey]

The carby is a Stromberg knockoff of an SU, it was common on the Rovers, Range Rovers and Jags etc. Bit more modern than the SU's .

 

Probably a 2 Inch, I have one at home off that I would be happy to sell. It was actually on a drawthrough mazda setup.

[DearmanKE]

ive alredy got a carby that I'm planning on useing for my setup, but out of interest how much would you sell for?

also pictures are good, if anyone has pics of sc setups on k motors chuck em in, don't mind if they are draw through or blow through as i am undecided yet.

 

issue with drawthrough... fuel pooling in the pipes and SC?

 

anyone know how much of an issue this is/can be with a draw through setup?

[kickn5k]

ive alredy got a carby that I'm planning on useing for my setup, but out of interest how much would you sell for?

also pictures are good, if anyone has pics of sc setups on k motors chuck em in, don't mind if they are draw through or blow through as i am undecided yet.

 

issue with drawthrough... fuel pooling in the pipes and SC?

 

anyone know how much of an issue this is/can be with a draw through setup?

 

I will be measuring everything for you tomorrow and ill take a couple of pis off it all close up aswell. The only draw back i could think of would be if you wanted to run an intercooler, and you had a backfire with fuel in the cooler it would make for a rather large bang!!

 

stu.

[SLO-030]

setup was not done by me it was done by local carby place in melb and I'm not to sure on size of su ill try find out for you

 

 

 

ps engine is very dirty lmao

 

Hey mate, would you be able to get any close up pics of the mounting setup/brackets?

 

CHEERS

Ryan

[DearmanKE]

I will be measuring everything for you tomorrow and ill take a couple of pis off it all close up aswell. The only draw back i could think of would be if you wanted to run an intercooler, and you had a backfire with fuel in the cooler it would make for a rather large bang!!

 

stu.

 

coolcool, be in touch

[kryton brown]

Definatly DO NOT use an intercooler with a drawthrough setup! The universe might have started with a BIG BANG but we don't want to see it end that way...

In draw through setup, the fuel going through the supercharger acts as a cooling agent also.

 

I found these calculations somewhere to work out the pulley ratios for superchargers.

 

When fitting a supercharger, you should match the swept volume of the supercharger to the size of the engine. If the choice is made carefully, problems from overboosting and the required paraphenalia to solve these problems will be minimised.

The supercharger will also be kept in its safe operating speed with correct selection.

 

To choose a setup you need to know :-

1. Engine capacity

2. Maximum engine speed you will be using.

3. Boost level desired

 

I am setting out the calcs needed for a 1200cc engine in the steps below.

 

FIRST CALCULATION (Engine Litres/min @ 0 Psi )

Multiply engine capacity (in litres) times maximum engine Rpm. E.g. 1.2 litres x 6000 rpm = 7200 litres/minute. Divide this figure by two as engine only fills every second stroke. (7200/2 = 3600 litres/min.

This is the engines air requirements in litres/minute at 0 Psi boost.

 

SECOND CALCULATION (boost ratio)

Add the boost pressure desired (7 Psi) for the engine to 14.7 Psi (atmospheric pressure).

(7 psi boost desired +14.7 =21.7 psi)

Divide this answer by 14.7 and this gives the boost pressure ratio. (21.7/14.7=1.476) This is the boost pressure ratio above atmospheric pressure.

 

THIRD CALCULATION (Actual air requirements @ desired boost)

 

Multiply the boost ratio by the litres/minute obtained for 0 Psi and you get the actual air requirements in Litres/min for the engine at that boost. In our example this is 3600 litres/min X 1.476 = 5313.6 litres/min for 7Psi boost.

 

To decide on the correct size of supercharger you need to know :-

1. The swept volume per revolution of the supercharger. (Eaton M62 1 litre/rev, SC14 from a 1G-GZE 1.5 litres/rev, SC12- 1.2 L/rev)

2. The maximum continuous safe operating speed for the supercharger. (Eaton M62 14000 rpm continuous, Toyota SC14 12000 rpm??)

3. The maximum pressure that can be safely produced by the supercharger continuously. (Eaton M62 12 psi, SC14 10-12Psi??? teflon on rotors melts??)

 

CALCULATION (Supercharger rotor speed)

Divide the desired air flow (5313.6 L/min) by the swept volume of the supercharger (SC14 from the 1G-GZE is 1.5 litres per revolution). This will tell you the maximum speed the supercharger rotors must be run at to produce the volume required.

5313.6/1.5 litres = 3542.4 rpm for the SC14.

5313.6/1 litre = 5313.6 rpm Eaton M62

 

CALCULATION (Pulley size ratio)

Divide the rotor Rpm by maximum desired engine rpm to get the drive ratio of the pulleys. For an SC14 on a 1200 @ 7psi boost the desired supercharger pulley ratio is

3542.4 /6000 rpm = 0.5904.

 

EXAMPLE OF CHANGE OF DRIVE RATIO

If the 1200 cc engines supercharger pulley ratio is increased to 0.75 using the 1.5 ltr/rev SC14 charger, the volume of air produced when running to 6000 would be 6000 x 0.75 x 1.5 litres =6750 litres/min

 

Boost produced would be 6750 litres/3600 litres (at 0 boost) =1.875 boost ratio For Psi boost ((1.875 x 14.7) - 14.7)=12.86 Psi.

 

if using an SC12 just substitute 1.2litres/minute instead of the 1.5litres/minute for SC14..

if you want to get even more technical the sc14 is actually 1.42litres/min! and even more so use the exact displacement of your engine eg. 3T-c is 1770cc..

 

If you already have a pulley, you can measure it and do the calcs backwards to see what boost it will make with that size.. you'll work it out..

 

Hope this helps. Sorry it's a bit long winded..

[DearmanKE]

yeah that really helped man, been trying to work out these calculations for the last few weeks with no avail haha

 

excellent post

[5kpanelvan]

Hey mate, would you be able to get any close up pics of the mounting setup/brackets?

 

CHEERS

Ryan

 

sorry dude i sold it a while ago was just trying to help what pics i had and with i had to get done to make it run

[SLO-030]

Ahhh fair nuff fair nuff. I will also be supercharging a 4k and using the carb Philbey has (same as the one you ran). Thanks for the pics you could supply. I be she went like a cut cat.

[kickn5k]

I measured the sigma pulley today for the sc side and it is 112mm minor dia and 135mm major dia.

I`ll measure the ribbed pulley tomoz when i get a chance to pull it out of the shed, And i`ll try to measure the crank pulley aswell.

 

hope that helps

stu.

 

kryton brown, Are these calcs for a positive displacement S/C or a centrifical S/C? Just asking as I'm helping a mate build his paxton(centrifical S/C) fed 355 holden. aswell as my sc/12 5K.

Edited November 6, 2008 by kickn5k

[DearmanKE]

for an sc12, they are positive displacement no?