Boost Controller

[AE82 FXGT]

Hey all, I'm after a boost controller the thing is my cars is supercharged not turbo (dunno if that makes a diff), anyway I don't want to put more boost on (I know I have to get a new pulley for that). It's more so that I can bleed the boost off when I don't want to go fast (an economy switch of sorts). An in cabin control would be preferable. It's just that I have no idea about this sort of thing, and a search didn't reveal much.

Thanks.

[Caveman]

You could have a switch to the supercharger relay to set it 'always off', 'ecu controlled' or 'always on'.

I dont know if the always on would open the abv on trottle off though.

Other than that theres no way you could use conventional boost control (waste gate control) to control supercharger boost.

It shouldnt boost unless you open it up though.

[AE82 FXGT]

Yea it doesn't boost when i take it easy, but sometimes I want to accelerate quick but not boost and it's annoying trying to find that point to how far you can put your foot before the supercharger engages. Plus I find it hard not too boost in second gear for some reason (unless I'm driving real easy, like my foot is just on the accelerator).

[slighty_sykotic]

No way around it. You can't really control boost. Just on or off.

What you could do is put a switch in line with the super charger relay so that when you don't want to boost, flick the switch, and you can put your foot flat without it boosting.

Best way to do what your wanting.

--Sykotic

[AE82 FXGT]

OK. That sounds sweet, could you gimme any sort of instructions?
Is it just a matter of putting a switch inline before the relay?
(will the relay for it be with the fuses, like with headlight relays etc?)

[slighty_sykotic]

Honestly i don't know where it is, i would guess in the engine bay fuse box though.

The easiest place to get at it though would be where it comes out of the ecu.

Have a search on here or google for 4agze ecu pin outs. You will get a diagram of the wires from the ecu, and then you just simply cut the s/c soloniod wire, and run the wires to a switch somewhere.

The ecu is under the stereo.

Might pay to get someone to help you if your not sure, you don't want to cut the wrong wire!

--Sykotic

[Caveman]

The ECU controls the supercharger relay.

Just intercept the wire (you can look up the colours and pinout on club4ag) and either

- earth relay (the wire not going into the ecu) - supercharger always on
- bridge the wires - ecu controlled supercharger
- break the circuit - supercharger always off

You should be able to get a switch that does this for cheap from electrics store

[Caveman]

Oh yea if you going to earth it for always on put a resistor inline with the earth just in case.

[AE82 FXGT]

OK so I have found this:

http://www.club4ag.com/faq%20and%20tech_pages/Turner%20Peter/AE92%20and%20AE101%204A-GZE%20ECU%20Comparison.htm

So am I correct in thinking that I need to just wire an inline switch from the 25th pin? Because I just want the supercharger to be off or ecu controlled, I don't want the always on option. So if the ecu is plugged in, it's on the bottom left of the plug, one wire to the right.

What does the SMC mean? And the B-Y would mean it's a black wire with a yellow stripe right?

Thanks for your help so far.

[Caveman]

Yep thats the wire. Dont worry about the name of the pinouts it could be anything. There are a few other diagrams on club4ag tech reference that you could use to cross reference.

Just make sure you get the right wire, pin 25 on a connection (26 pin plug) because the ignitor has a black yellow wire and you dont wanna cut that

[AE82 FXGT]

So do you know if anyone has done this sort of thing before?
Will it have any adverse effects on anything else?

[mjrstar]

[/quote]No way around it. You can't really control boost. Just on or off.

What you could do is put a switch in line with the super charger relay so that when you don't want to boost, flick the switch, and you can put your foot flat without it boosting.

Best way to do what your wanting.

--Sykotic

why not fit a wastegate to your inlet manifold, sure you'd need to plumb it out of the engine bay.. i have a friend trying this on a mk1 cortina (has not been tested yet) but i see no reason for it not working. just plum it in the same as running an external on a turbo car..

[Caveman]

So do you know if anyone has done this sort of thing before?
Will it have any adverse effects on anything else?

Adverse effects will be slowness which will suck

Wastegate on the inlet sounds expensive

[slighty_sykotic]

You would have to have a light as hell spring in the wastegate. In fact, a bov would be better, just modify a piston type bov to act as a wastegate.

And yes, in theory it would work, but I have to ask why? Its a s/c car for a reason, to make lots of power, if you dont want power, then dont drive with s/c, or turn it off. Whats the point in trying to do it half way?

--Sykotic

[matt dunn]

If it is an early AE92 and has an AFM, there there is nothing you can do, as bleeding off air will make it run rich. Too rich to run probably.

Give up, it is not worth it.


If you want more economy, trade it in on a 4AFE powered one.

Matt

[CozmoNz]

The ECU controls the supercharger relay.

Just intercept the wire (you can look up the colours and pinout on club4ag) and either

- earth relay (the wire not going into the ecu) - supercharger always on
- bridge the wires - ecu controlled supercharger
- break the circuit - supercharger always off

You should be able to get a switch that does this for cheap from electrics store

wanna make it easier for some people and just do a wiring diagram?

[Quint]

your car will have no top end power if you turn off its boost as it'll have a low compresson without the S/C to compensate/raise it. EG. no go above 3g rpm

[Caveman]

The ECU controls the supercharger relay.

Just intercept the wire (you can look up the colours and pinout on club4ag) and either

- earth relay (the wire not going into the ecu) - supercharger always on
- bridge the wires - ecu controlled supercharger
- break the circuit - supercharger always off

You should be able to get a switch that does this for cheap from electrics store

wanna make it easier for some people and just do a wiring diagram?

noob

Someone correct me if im wrong, maybe 100k is too much on the resistor?

corrected thanks matt dunn

[Caveman]

your car will have no top end power if you turn off its boost as it'll have a low compresson without the S/C to compensate/raise it. EG. no go above 3g rpm

Yep car will be slow as hell without the supercharger, basically 4agze without boost would only make 75HP because of crappy intake. compression doesnt affect it that much, bluetop 4age is 9.3:1 compared to 8.9:1. Not much difference.

[matt dunn]

someone correct me if im wrong, maybe 100k is too much on the resistor?

Um, yeah will be a bit high I think.

I would actually use no resistor at all as it on the earth side of the relay.

Matt