CO Potentiometer

[Gazza]

Am I right in saying that S2's don't have these, as they have the O2 sensor?

Are they only fitted to N/A's and SE's without cats?

Cheers, Gazza

[GeoffSmith]

Closed loop: O2 sensor = No CO pot.

Open loop: No O2 sensor = CO pot.

Closed loops usually have cats, but some don't.

[rip]

If I were to retro-fit my SE with an O2 sensor (when I upgrade my ECU), am I correct in assuming that the CO sensor wil simply be ignored?

[Enright]

Yes you are.

But I'd recommend going the V5 route and having half SE and half S2 programs. Then if the O2 sensor ever fails you can simply switch back to open loop while you replace it.

[Gazza]

Cheers lads for the answers

Gazza

[rip]

Yes you are.

But I'd recommend going the V5 route and having half SE and half S2 programs. Then if the O2 sensor ever fails you can simply switch back to open loop while you replace it.

Excellent idea. That will also allow me to upgrade the ECU first and simply switch to a closed loop program when I fit the O2 sensor.

Reading the mountain chips thread will keep me quiet for a while too

[Monty]

Yes you are.

But I'd recommend going the V5 route and having half SE and half S2 programs. Then if the O2 sensor ever fails you can simply switch back to open loop while you replace it.

Neil,

Pinky II has never been great on fuel consuption and i was thinking off fitting the O2 sensor as you have done but now i`m on the list for Marie`s bigger Turbo kit. Do you think there would be any advantage fitting an O2 sensor with the bigger turbo, injetcors etc? (with an closed loop chip)

[Enright]

Wow, that one made me think Monty!

I think that there WOULD be an advantage, but you've got to get everything right in the system. Having said that - God would it be worth it? Not arf pop pickers!

You have to think about what each component does, and what it allows you to do.
Putting an O2 sensor in allows you to monitor the air/fuel ratio and only then to correct it to 14.7 to 1. At that point you get the most efficient burn, and so the biggest bang for your buck.
That means either most economical, most powerful, or somewhere in between (depending on the weight of your right foot)!
Remember that the operative word above is "monitor".

The bigger turbo is going to chuck in more air (and a BB one will ramp up quicker too). The bigger injectors are going to chuck in more fuel. And a bigger MAP sensor will be able to monitor the higher pressure that you can now run at.

But you're still going to need a way of controlling it all, and this is where I would approach Alan.
IF you could get all of these things to use standard connectors and voltages to link into the existing setup, and get a "Double Everest" type programme to control the increase boost while maintaining the correct air/fuel ratio ALL THE WAY THROUGH THE REV RANGE (and therefore maintaining the existing safety features but just at a higher level), then the result would be, in a word, badass!
We're talking Sh4rk type of performance without the NOs.

This is getting into ultimate project creep territory because you're now going to be going right up to and possibly well beyond the intended design specs of the clutch and possibly the pistons, head-gasket and crank. The last thing you want to be doing is blowing bits of piston through your nice shiny new turbo and wrecking all your good work. That's why I'd steer well clear of any MBC's and FCD's.

Of course, it's not mandatory to drive it on max boost all the time, and it should still behave itself if you drive "normally". But come on be honest - with that much tempation, would you?!? It would be fun for a while though!

[GeoffSmith]

Maybe worth asking Alan if you could fit a wideband O2 sensor.

[Monty]

Thanks for the reply Neil, IIRC i think Alan is doing a chip for Ekapol with the Garratte turbo and they`ve got an O2 sensor, so maybe i should go down the same line.

So i need to get myself a cheap 02 sensor, Neil, how did you go about wiring up the O2 sensor?

[Enright]

Sounds like the best plan.

I'd go to Rockauto and get this one if I were you:
BOSCH Part # 15726 {Oxygen Sensor}
3 Wire; Heated; Check / Replace Interval: 100,000 Miles; Universal Type - Upstream
(It's in the emissions section for the 91 Isuzu Impulse RS)

And wiring it up is dead easy - you just plug it in!
The plug is already there - just next to the driver's side headlamp motor.

[rip]

Monty,

I don't think the turbo is relevant since the O2 sensor is only used when there is no boost being provided.

So it would be good for normal driving, but would not do a lot on a trackday.

[Monty]

Thanks guys, sounds like it`s worth fitting one even if it`s just for traveling to the track

[ailwyn]

Jay,

You might want to hold off on the O2 sensor for the moment, if you are planning on going big turbo, big injectors, 3 bar map, then you'll be wanting a new ECU which would probably benefit (at least for setting it up and monitoring) from a wideband O2 sensor.

Ailwyn

[Enright]

That's beyond my level of experience Ailwyn.
What's the difference? Don't say one's narrow and one's wide!
I mean what advantage does the wideband sensor offer?

[Monty]

Jay,

You might want to hold off on the O2 sensor for the moment, if you are planning on going big turbo, big injectors, 3 bar map, then you'll be wanting a new ECU which would probably benefit (at least for setting it up and monitoring) from a wideband O2 sensor.

Ailwyn

Ailwyn,

Thanks for that, but are we not sticking to the stock ECU and IIRC Alan is doing a chip for Ekapol + Marie & Ekapol still have the O2 sensor in place.

I haven`t a clue on all this but i`m just going to do what ever Marie has done and maybe in the future fit a Haltech

[GeoffSmith]

Neil,

Narrow band sensors only have two states and change over a very narrow range, so the A/F ratio is actually bouncing around between slightly rich and slightly lean. A wideband sensor has a more gradual progression over a wider range, so the mixture can be set and maintained much more accurately.


Definitely a case of analogue being better than digital.

[Enright]

Hmm, that being the case, can't you compensate for it with a decent sampling rate?
Also won't it require a different program to monitor the other type of sensor, or is the wideband backwards compatible?