AIR / FUEL RATIO GAUGES

[bclancy]

Hi guys

Can any one tell me if the lambda sensors fitted to RV8 'hot wire' type engine exhuasts are narrow band or wide band OR am I being dumb and they have wires for both? LOL! The reasion is I want to fit an air fuel ratio gauge when my new engine goes in, to help me set the new mods up.
By the way, I take it that it would still work/read ok when running on LPG too?

Sorry for the 'dumb' question

Brian

[sidecar]

Hi guys

Can any one tell me if the lambda sensors fitted to RV8 'hot wire' type engine exhuasts are narrow band or wide band OR am I being dumb and they have wires for both? LOL! The reasion is I want to fit an air fuel ratio gauge when my new engine goes in, to help me set the new mods up.
By the way, I take it that it would still work/read ok when running on LPG too?

Sorry for the 'dumb' question

Brian

A bit of a guess but I reckon that it will be narrow band as that is what most manufacturers use. Therefore it will be no good for for an air/fuel gauge. Like I said it's a guess though!

[ChrisJC]

I'm pretty sure they are narrowband too.

I used an Innovate LM-1 on my vehicle.

They work on LPG too, however you have to get your head around the fact that they read Lambda and multiply by 14.7 to get the reading you expect. For LPG, that constant should be 15.something.

So in practice, when your LPG is set up properly the lambda sensor will be reading the same as if it were running on petrol (i.e. 14.7:1), yet in practice it is running at 15.something:1 which is correct.

Does that make any sense???

Chris.

[Quagmire]

I remember that point blew my mind for a while too

[bclancy]

Hi chaps

Errrr, no not really??? LOL! But I have seen a few narrow band gauges (half decent ones) for about £50 (you can get cheaper but would you?) and just thought it would be a good way of dialing in a few adjustments on both petrol and LPG to allow for the cam change/higher C/R, and ported heads I'm fitting too.

Also having a serious think about megajolt too.......

[DEVONMAN]

Hi chaps

Errrr, no not really??? LOL! But I have seen a few narrow band gauges (half decent ones) for about £50 (you can get cheaper but would you?) and just thought it would be a good way of dialing in a few adjustments on both petrol and LPG to allow for the cam change/higher C/R, and ported heads I'm fitting too.

Also having a serious think about megajolt too.......

As sidecar said above, narrow band sensor and gauges (cheap or expensive) are no good for setting up mixtures. All they tell you is that your mixture is either rich or weak either side of 14.7, which is what the ECU needs to know to correct the mixture.
Wide band will tell you the actual ratio.

Regards Denis

[bclancy]

Thanks Denis

I hear what your saying and it makes sense! Just th guage manafacurer states 'connect to your narrow band sensor' !!!!!?????

I have seen wideband kits with a sensor/guage, but would a wideband be compatable with the ECU? also are the wideband sensors '4 wire' ??? Sorry to keep asking questions, but on a learning curve here, always been a carb man so injection is new to me! lol

[sidecar]

Hi chaps

Errrr, no not really??? LOL! But I have seen a few narrow band gauges (half decent ones) for about £50 (you can get cheaper but would you?) and just thought it would be a good way of dialing in a few adjustments on both petrol and LPG to allow for the cam change/higher C/R, and ported heads I'm fitting too.

Also having a serious think about megajolt too.......

As sidecar said above, narrow band sensor and gauges (cheap or expensive) are no good for setting up mixtures. All they tell you is that your mixture is either rich or weak either side of 14.7, which is what the ECU needs to know to correct the mixture.
Wide band will tell you the actual ratio.

Regards Denis

And just to add to that, 14.7:1 is no good for max power anyway, it is just the chemically correct ratio for petrol but it is not the best ratio for power or max economy. (Having said that, I can not get my motor to run well even when cruising with a ratio that is as lean as 14.7:1 )

Really if you want to get into setting up the mixture and you have a carb you either need to spend hours on a rolling road or use the real road as your rolling road in conjunction with an LC1 or something similar.

If you go for a mega squirt EFI or whatever they are called then I believe that has a wideband built into the whole system.

[bclancy]

Thanks Denis

I hear what your saying and it makes sense! Just th guage manafacurer states 'connect to your narrow band sensor' !!!!!?????

I have seen wideband kits with a sensor/guage, but would a wideband be compatable with the ECU? also are the wideband sensors '4 wire' ??? Sorry to keep asking questions, but on a learning curve here, always been a carb man so injection is new to me! lol

[sidecar]

Thanks Denis

I hear what your saying and it makes sense! Just th guage manafacurer states 'connect to your narrow band sensor' !!!!!?????

I have seen wideband kits with a sensor/guage, but would a wideband be compatable with the ECU? also are the wideband sensors '4 wire' ??? Sorry to keep asking questions, but on a learning curve here, always been a carb man so injection is new to me! lol

I don't think your ECU will like it if you you just screw in another sensor, you could always fit another boss into the exhaust and screw a wideband into that. The four wire devices are just two wire devices but with a heater element, I think.

If you are running an ECU system how were you going to adjust it anyway?

Your questions are not "dumb" search this forum or any others and then you will find some real dumb questions!

Pete

[bclancy]

Hi Pete

Thanks for your time. The reasion I want to fit it is beacuse the car runs 99% of the time on LPG (but I need to be able to run on petrol). I can adjust the 'mixture' on the LPG with some software and interface I'm going to buy. I'm just about to pick up another bottom end from a fellow forum member and without going into details, with the the 10 bolt heads im getting and the H/C pistons etc it will now be running around 10.75:1 C/R, plus I will be pocket porting the heads and fitting a 270/2 cam, K&N, headers, possibly a megajolt too. Hence the need to make adjustments!

I'm not a fan of rolling roads (used plenty over the years) as I have often still ended up 'tweeking' a motor afterwards to get a more tractable and often more powerfull setup (confirmed by standing quarter times). I think this is usually caused by operators looking for ultimate HP numbers too much, so as to impress! Not to mention the cost and the fact that most engines are ongoing developments and as such would require regular visits to the rolling road.

[sidecar]

Hi Pete

Thanks for your time. The reasion I want to fit it is beacuse the car runs 99% of the time on LPG (but I need to be able to run on petrol). I can adjust the 'mixture' on the LPG with some software and interface I'm going to buy. I'm just about to pick up another bottom end from a fellow forum member and without going into details, with the the 10 bolt heads im getting and the H/C pistons etc it will now be running around 10.75:1 C/R, plus I will be pocket porting the heads and fitting a 270/2 cam, K&N, headers, possibly a megajolt too. Hence the need to make adjustments!

I'm not a fan of rolling roads (used plenty over the years) as I have often still ended up 'tweeking' a motor afterwards to get a more tractable and often more powerfull setup (confirmed by standing quarter times). I think this is usually caused by operators looking for ultimate HP numbers too much, so as to impress! Not to mention the cost and the fact that most engines are ongoing developments and as such would require regular visits to the rolling road.

I know the block that you are going to buy....I would not touch it with a barge pole!!.........Just joking (The bod selling it is a good guy and won't rip you off)

I agree with you on rolling roads, I'm sure that some are OK but I'd rather buy an LC1 and do the tweaking myself.

My engine is always being fiddled with so it would cost me a bomb to have it dyno'ed every 5 minutes. I did succumb once and it made about 285 BHP which I thought is not too bad for a motor built in my shed!

Pete

[bclancy]

Hi Pete

Just read the first line of your reply and nearly cried (till I finnished reading it hahahaha) SOD!

Well, I've done lots of 4cyl jobs on nice easy to tune and set up DCOE's and the like, but injection is new to me, so steep learning curve! I'm an old skool chap, Mk1 RS2000's, very silly spec, offset valve, split 45 minis with straight cut boxs etc! lol Okay, first off, what is an LS1 (keep hearing this term on here!?????) I take it its a wide band sensor?

P.s. 285 bhp sounds nice lol!

[DEVONMAN]

Thanks Denis

I hear what your saying and it makes sense! Just th guage manafacurer states 'connect to your narrow band sensor' !!!!!?????

I have seen wideband kits with a sensor/guage, but would a wideband be compatable with the ECU? also are the wideband sensors '4 wire' ??? Sorry to keep asking questions, but on a learning curve here, always been a carb man so injection is new to me! lol

Narrow band sensors put out a voltage and wide band sensors put out a current which varies with fuel ratio. So, you cannot just swop a NB sensor for a WB sensor. However some wide band gauge units have an output to drive EFI systems but you would need to do some further research before you invest given the cost of wide band sensors /gauges.

If you wire in a narrow band gauge to an existing narrow band sensor/ecu set up then the gauge will show rich when the engine is in warm up mode and then the gauge will oscillate between rich and weak when the engine is warmed up and running in closed loop mode. This oscillation shows that the ecu is continually correcting the mixture.
When you floor it, the gauge should show a richening of the mixture.
On overrun the gauge will show lean if your system cuts the fuel on overrun.
However the narrow band gauge will not tell you the actual mixture.

Regards Denis

[Cobratone]

I can not get my motor to run well

I think I'll save that quote