Offroad-Express

I have got a Toyota belt driven super charger as fitted to a 6 cylinder (not a 4AGE) cressida ?. Has anyone fitted these to a 5m and if so what has been the increase? or am I just mucking around for nothing I understand these pump at max 8 psi. Has any one got the mounting brackets? I have done a quick troll thru the net and havent come up with any fitted to a 5m or 7m.
cheers

ya could give it to me and i'll try it out for ya

came off the 1g motor would be good on the 5m you just need to make some mounts, boost is only limited by the revs the blower spins at but will handle 15 psi, on a std 5m you would only want 4 or 5 psi but you would notice the extra power for sure.
vaughan

Back in my limited Turbo days, I remember being amazed by the improvement the first 5psi made over N/A.

boost is controled by the size of the pulley I have the notes on pulley size somewhere I will try track them down.

you need to mount the charger up very accurate otherwise they throw their belts off all the time, also the higher the boost the harder it is on the engine and you need to run a bypass (preasure release) valve post the charger in case you ever get a backfire to allow the pressure to be released the charger is post air filter and afm also if you have the airflow meter in front it gets confused by the pulsing.

last couple of things is it has to run clockwise, this is the way the teflon coating was designed, a charger rob's horse power from the crank and gives it back in torque so speeding the idle above 1000 rpm will help prevent stalling and it gives low down torque, unlike a turbo it is most efficient lower in the rev range. Watch the engine intake temperatures. Also boost is not usualy able to be properly corrected with a standard computer and boost over 4 PSI is not able to be fueled with a standard computer (you are running lean). Watch the engine exhaust temperatures.

AND TAKE PHOTO'S OF THE INSTALL AND DOCUMENT THE BELTS USED FOR THOSE THAT FOLLOW!

I will see if I can track that pulley size stuff I have somewhere

Edit to say I found it but I am posting it after this anyway so not sure why I edited this post

OK Mega Post Alert and if you fit a Supercharger you need to understand the maths!

Most engines will take 5 - 6 Psi boost without doing any mods other than timing to prevent detonation from increased cylinder pressures.

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 paraphernalia and tricks 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 2200cc engine in the steps below. (Because I have already done them to suit)

FIRST CALCULATION (Engine Litres/min @ 0 Psi )
Multiply engine capacity (in litres) times maximum engine Rpm. E.g. 2.2 litres x 5500 rpm = 12100 litres/minute. Divide this figure by two as engine only fills every second stroke. (12100/2 = 6050 litres/min.
This is the engines air requirements in litres/minute at 0 Psi boost.

SECOND CALCULATION (boost ratio)
Add the boost pressure desired (4 Psi) for the engine to 14.7 Psi (atmospheric pressure this is the weight of air for a better description).
(4 psi boost desired +14.7 =18.7 psi)
Divide this answer by 14.7 and this gives the boost pressure ratio. (18.7/14.7=1.272) 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 6050 litres/min X 1.272 = 7695.6 litres/min for 4Psi boost.

Still with me? That bit is the easy bit!

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)
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 10Psi??? Heat issues??)

CALCULATION (Supercharger rotor speed)
Divide the desired air flow (7695.6 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.
7695.6 /1.5 litres = 5130.4 rpm for the SC14.
7695.6 /1 litre = 7695.6 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 2200 @ 4psi boost the desired supercharger pulley ratio is
5130.4 /5500 rpm = 0.9328. So With an 8" shaft pulley (the diameter or distance around the pulley) on the supercharger the crank pulley for this ratio would be 7.462".

EXAMPLE OF CHANGE OF DRIVE RATIO
If the 2200 cc engines supercharger pulley ratio is increased to .8 using the 1.5 ltr/rev SC14 charger, the volume of air produced when running to 6000 would be 6000 x 0.8 x 1.5 litres =7200 litres/min

Boost produced would be 7200 litres/6050 litres (at 0 boost) =1.190 boost ratio For Psi boost ((1.190 x 14.7) - 14.7)=2.73 Psi. at idle and 4 + 2.73 psi at full boost (6.73PSI)

Hope this helps.

Yes I am a maths geek and Yes I am a computer Geek to find all this crap in the first place, now I need a rock to hide under!

Edit: to correct for finger problems and correct the maths thanks NJV6. Oh second edit to correct spelling in the edit

That was awesome!

One mistake - Third Calculation should be 6050 * 1.272 & not 6050 * 1.476 (but it all works out the same - only the figure was wrong)

A+

not sure what blower but the one on a 4agze will handle alot more boost/ revs than that , we ran a 4agze at 18 psi 302hp, anyone old enough to be at the first 4cyl and rotary nats would of seen it win the 4cyl burnout in a green ae 86. that super charger sat in the shed for over 3 years then we fitted it thrashed the living crap out of it and it still lives, run good oil and change it often, i used the factory oil the jag xks blower ran on.
vaughan

OK I was going with continuous use and using factory service intervals, changing the oil and increasing the quality of the oil will help but the plastic and teflon coating's in the charger and bearings wear much faster at higher rpm.

Also the sc14 are rated for 500,000km factory, pushed hard they will not make that and a bearing or seal failiure in a hard worked engine could mean that metal goes through the engine.

This was also for a NA engine you can get higher boost if you look at decompressing the engine (Head work, shorter rod's, deep dish piston's and other methods) but this is further than the inital Question. Also the Supercharger (any supercharger) is more efficient at lower rpm this is why the V8 boy's have much larger versions again turning slower.

Good stuff Steve
Suggestion that this goes somewhere in the Techy dept.

Nice to see logic displayed for others to learn from

Gee my head won't fit out the door soon!

Mike can move it to Tech if he thinks worthy but I am not sure how many of us will be fitting Superchargers, the 5,6,7m engines are all revy and high end power a charger would give more low down torque but could cost the engine at higher rpm (heat the air in the intake)

Thanks for all that .. yes its technical but thats exactly what I required. Although I havent done the calculations yet ( over time and other work stuff) it appears that its feasible. I'm planning on 4 lbs psi and as said, the toyota is a revy motor and if it means giving up some top end revs for low down torque then, to me, thats a bonus.
Rev's equal wear, torque equal power.
The motor 2.5 5m has had head work ,ports opened up , cams ground to a slightly higher lift, same duration but faster ramp speed, 7m injectors and an improved exhaust, has been on a dyno and was rated at 198 hp ( can't remember torque numbers )but that was not long after the motor was built. would anyone like to take an educated guess at torque and Hp increase figures?
when I catch up with you guys it looks like its going to cost me a fews beers
cheers

at 4psi you should be adding around 70 HP but the trick is it may not be where your previous peak HP was so I would be happy around 250 and loads of low down torqueand with the 7m injectors you may get a little more as the mixture gets leaner closer to what the factory is programmed for.

Take pick's more people could be interested in this than you think. Matt4u would be one, but I think in offroading with Prtrol the good old simple charger is way under rated.

So I should fit one, but other mod's to come first

EDIT to add:

Your acceleration low down in the rev range will be far improved too don't be discouraged if you want more power, a supercharger give much more useable power and the peak power curve is no longer a spike but a broard butch looking graph

I want to supercharge the 2JZ one day...

ive got an old toyota supercharger im thinkin of fitting to the v6 pajero, if i ran 4-5 psi would i need any other mods? maybe a adj fuel reg to get a little more fuel in there, what would be the go with the efi systen factory?

Ok Steve_t647, here's another question for you.

I've been given a Toyota s/charger off a 2.0L petrol apparently, so I assume it's an SC14. Without doing the math accurately I can safely assume from your earlier post that it will be running at really low revs if I mount it for about 5lb boost on my 1590cc Suzuki (approx 3000-3200rpm). Are these chargers efficient at these low rpm, or would it be too mis-matched for this application?

Sorry for the slow reply, there has been a bit going on and the site lost its way a little. A supercharger can be geared (for want of a better word) to give boost at any rev's by a larger or smaller pulley. Most likley you have a SC12 from the 2.0 litre they are 1.2l per revoloution and would match the motor pretty well with the correctly sized pulley.

all superchargers will give boost early in fact you can get boost at idle but this usualy this means you have problems higher in the rev range.