4agze super-charger switch?!

[too_quick]

^^^Jorrs^^^
GZE's have big and small port heads, Both use 7 rib blocks, aw11 is dizzy and bigport, early ae92 is CAS and bigport, late ae92 on is smallport.

[feral4mr2]

what block do the ZE 4ag use ? as feral said they perform poorly when the SC is switched of, are they are bigport block ?

the aw11 4agze is a bigort and the later 4agze's are a smallport. not that i have tried it with a smallport 4agze, i boubt one would run any better than mine with the s/c switched off.

i see no point of a mad max switch on the gze after trying it.

[wiso]

Fuel economy comes down to driving style and includes many different tricks. It's actually a skill to be able to drive your car in an economic fashion.

By disconnecting the 'charger, you'd be hoping to benefit from economising during acceleration. To get the most economy from your car whilst under acceleration, you need to accelerate in a fashion that keeps the car running as lean as possible. Basically, this means accelerating slooooowly, with minimal accelerator pedal input.

The 'charger doesn't engage unless you're up it anyway. If the car is under load - which would mean the fuel mixture is on the rich side - it would probably be more beneficial economy wise for the 'charger to kick in and provide boost, helping volumetric efficiency, and you might even be able to run a little leaner than if you were off-boost, as the 'charger helps the engine to pull, rather than struggle.

actually you will be very suprised, the 4agze is at its most economical point when you are making it produce a couple of pound of boost.

if you drive the car normally the clutch will engaged and spin the charger to about 1-2psi, if you try and drive it off boost all together you will find the engine becomes to labourous and lathargic to get anywhere, especially above 60km/hr.

there have been tanks of fuel where i drive using almost 0 boost and found my fuel economy worse than when just driving the car normally using a little bit of boost. after all when accelerating its very sensitive to turn on so the ecu is designed to utilise it.

IMO at least

[mic*]

I agree with Wiso, its a skill to drive a GZE efficiently. And i guess that is the reason i was happy to get rid of the clutch. I didnt do it with a switch but thats another story. Heres the wiring diagram for a "mad max" switch thats been mentioned. If the link is not to the last page, go there...

http://www.toymods.net/forums/showth...ghlight=switch

The idea of the clutch is that it kicks in at the point where the power to be gained exceeds the power of driving the blower, and the extra fuel consumption is only due to extra power production. However the sudden changes in torque make throttle control far less smooth adversely affecting economy. If the clutch kicks in earlier, the smoothness is improved but you are adding a load to the engine before it has reached its own max capable breathing potential.

Moreso i think the efficiency struggles of the GZE's lie in the undersized ABV which does not breath enough for the VE to be efficient under light loads approaching zero vac. This makes the "SC on - SC off" Mr Miyagi chant well know to the GZE owner...

An interesting little point for thought; Toyota sets up the system so that the ABV closes momentarily BEFORE engaging the SC clutch. This is so that the engine "sucks" the lobes into spinning a bit first, to extend the life of the clutch. I think stuff the clutch and let the ABV stay open till momentarily AFTER the SC is engaged, and the fuel that gets saved can be tucked away to save for new SC clutches

The main benfit of the clutch IMO is far less heatsoak.

[McFly 11]

A supercharger switch IS safe IF you do not use it while the car is in motion and there is a risk of the supercharger sudddenly engaging/disengaging at high engine RPM. That is your only real risk of damaging anything with an SC switch

It can be worthwhile to use if you want to keep your licence or save fuel on overall driving but as 011 says its more about the way you drive

I have gone through several designs of supercharger controllers on paper to do the above mod and a bit more. The final model (under construction) allows manual disabling of the supercharger and boost-sensing override for twincharging (and an "always on" mode for lining up against pretenders at the lights ). I had my 4agze engine compression raised to 9:1 (like the later 160 hp GZE) to provide better drivability when not using the S/c and I also have shortened the intake pathway as much as possible (although the benefit of this is yet to be proved). So far with the supercharger disabled the car is still a bit sluggish to drive but it does chew less fuel with my impatient driving style
BTW it is an auto. I bet the manual would allow even more efficient driving if the inclination arose
Edit: I know the auto has taller gearing up top but you have so little control over the selection. I do hardly any highway driving anyway

[Mr Revhead]

4agzes arnt thirsty
they use more if ya thrash them, but if you want to thrash you want boost....

a 4agze with no boost = id rather walk.

so basicly, dont bother with a switch

if your looking at buying one with a switch, just remove it. it wont have done anydamage.
however i would look for other silly non educated mods that may have damaged it...

[feral4mr2]

A supercharger switch IS safe IF you do not use it while the car is in motion and there is a risk of the supercharger sudddenly engaging/disengaging at high engine RPM. That is your only real risk of damaging anything with an SC switch

and you dont think the ecu switches the s/c on and off at high rpms?

It can be worthwhile to use if you want to keep your licence

if your going to speed with it switching via ecu control, then you'll still speed with the s/c switched off. it'll just take a little longer to get over speed shall we say...

[Hen]

It's a simple matter to wire a 3 pos - on, ECU controlled and off - switch for the SC clutch. Sorry I'm in a hurry and don't have time to draw the diagram now, though I think I've posted it before. Whether it is any use is still debatable. May be handy when lending your car to people, so you can just leave the SC off.

I am 100% concurrent with feral's first point above. I've never seen or experienced any clutch damage from high RPM switching and I've done a fair bit of it.

Hen

Hen

[mic*]

[IMG][/IMG]

You mean this...? This is what the link on the first page goes to...

Yellow wires are the added bits for a permanent SC-ON override. If for some reason you want the permanent off switch, and i can tell you there is NO good reason, adapt as follows;

Get a three position switch. CUT the wire from relay to ECU and join the yellow wire to the realy end, rather than tee into it. The drawing as above with the switch open will now be permanent off. Then add another wire from the third position on the switch and run it back to the cut wire goin to the ECU - factory function.

[McFly 11]

and you dont think the ecu switches the s/c on and off at high rpms?

Dead right, you can make the ECU activate the SC relay at speed but it is hard to get the ECU to do that at 6000+ rpm as it tries hard to avoid doing this by design. A person could be tempted to flick the sc switch on at this speed, or worse still a poorly connected swich could cause the clutch to flick on and off. This would add up to more wear and tear on the clutch than would normally be expected. That is what I was referring to as a "risk of damage"

if your going to speed with it switching via ecu control, then you'll still speed with the s/c switched off. it'll just take a little longer to get over speed shall we say...

Hey i did ride on 011s coat tails and say it was ultimately about driving style

Removing the sc clutch does help move that temptation further from reach... but it is a pretty lame basis for installing the mod. Unless you really can't help yourself you would need better reason than that for installing it. (I still got all my licence points tho!)

[McFly 11]

You mean this...? This is what the link on the first page goes to...

Yellow wires are the added bits for a permanent SC-ON override. If for some reason you want the permanent off switch, and i can tell you there is NO good reason, adapt as follows;

Get a three position switch. CUT the wire from relay to ECU and join the yellow wire to the realy end, rather than tee into it. The drawing as above with the switch open will now be permanent off. Then add another wire from the third position on the switch and run it back to the cut wire goin to the ECU - factory function.

Hen, you are right but i had a little trouble following your description Mic* (probly just me ). I edited the pic to be a little clearer for a 3 position switch - that is more or less how I tested my SC controller proof of concept.



Worked a treat for short spurts of "permanent on" but I wasnt game to test the limits of the em clutch staying on forever.

Heres a piccy of a 2 position switch I used (no need for a 3 position to test it really)


As you may see the wire to tap into is the red wire with the white stripe, not the solid red wire (or any other). I used a yellow wire for earthing coincidentally but I hope it helps relate to what Mic* was saying

[mic*]

Good edit to the pic McFly. CBF doin it myself.

I think the point trying to be made by the experienced guys above, is that damage to the clutch is at best highly unlikely...

Let me throw a comprimise out there and say; that the clutch & belt life may be reduced if you go around deliberately revving up your motor to 6000rpm and flicking the switch while STILL UNDER LOAD.

For all practical reasons i cant see why you would do that... Normally if a driver wants power his/her brain knows this before the foot goes down and as such i would have thought the aforementioned brain would appreciate that flicking the switch would come first...

[feral4mr2]

Dead right, you can make the ECU activate the SC relay at speed but it is hard to get the ECU to do that at 6000+ rpm as it tries hard to avoid doing this by design.

mate both my gze ecu's will engage the s/c at higher rpms. they have done it many times.

[McFly 11]

Hi Feral, no arguments there but I want to look after my sc clutch. They are cheap enough to get second hand at the moment but I would hate to have to look in a few years. I hope there were enough supercharged Previas sold in Japan to guarantee a steady supply

Some of you may have read this but for posterity's sake:

Welp...

Genuine bits are priced more rediculously than I imagined!

About $2950 for the major clutch bits.... my god...

Because that is what the clutch will cost you new from toyota

Back to the main topic... Another important thing to add. If anybody out there still chooses to go for a switch and you are shopping for one to install in your "dash hole", make sure you choose one that has a high contact current rating for safety's sake.

I couldnt find the specs for the draw current of the supercharger relay (I suppose I could measure it when I get time) but it could take a couple of amps or more to trigger - most auto switches do this fine but many cheap 'flashy' switches from the major electronics retailers will not especially not their rotary switches like the diagram could imply.

Unless you are buying old mil spec switches from ebay (must be break before make as well) avoid rotaries altogether, otherwise purchase any other quality part as long as it handles a fair bit of power for good cheap clutch insurance (I was using a switch rated for 6 amp @ 120v for ref).

Hope that is of use to anyone who is still considering this mod (apparently against good advice )

[011]

^ You'd just get another SC12. They're not that uncommon.

Or an SC14...