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Discussion Starter #1
After spending many thousands on building my engine I want to have all the right bits N pieces to try and spot quickly any problems that may occur.

Ruling out the likes of the ‘Stack’ displays etc as being too expensive and also not fit in with how I want the interior to look, I’ve decided that gauges are the way to go.

This is what I’m thinking at the moment:
Volts
Oil pressure
Oil temp -measured at drysump oil tank – this is the standard place for it
Oil temp - measured in engine
Water temp
Fuel pressure – pressure at fuel rail

Now I also want to be able to keep an eye on what is happening in the combustion chambers.
I believe there are 2 ways of doing this:

1. Air/fuel ratio meter
2. Exhaust gas temperature.

Now doesn’t number 1 use the lambda output? If so there maybe a problem me using one anyhow as I’ll be running SBD’s new wide range lambda, so whether they are compatible I’m not sure.

For number 2 I’ve haven’t a clue how it works, except that it records exhaust gas temp.
Where is it mounted?
What is the ideal temp?
How do you know when something is wrong?
What would a high / low temp show?

So anyone have any comments of the above? – Especially on measuring combustion chamber activity?
Any other ways of doing this?
 

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I've currently got

Volts
Amps (for battery charging status)
Oil temp
Oil pressure
Water Temp

The 2 oil temps would be usefull at the beginning for sorting the oil cooler etc, but as long as you know when it's warm (or not) then it's as much as you'll get from it imho.

I was tempted to do fuel pressure, but you really need an undamped capillary setup to actually see wft's going on, and putting this through the bulkhead is a bit risky, and an MOT fail, I think.

The AFR is done using the lambda, it'd probably be worth welding a second boss into the manifold, then you could use an off the shelf kit which comes with a dedicated lambda sensor.

I know FA about exhaust gas temp gauges and senders, but high exhaust temperatures are usually an indicator of a lean mixture.

There's one omission off your list, though. one of those GPS based acceleration timers. then you'll really know how well your engine's performing :)
 

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Discussion Starter #3
Amps - yep meant to include that in my first post. :rolleyes:

Yeah probably is worth the extra boss in the exhaust for the AFR lambda.

Still interested in finding out about exhaust gas temp. Arno fo EDS mentions it alot as a guide to when those dodgy old LET pistons are about to squidgy.

Out of interest what does you Stack do?
 

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Now doesn’t number 1 use the lambda output? If so there maybe a problem me using one anyhow as I’ll be running SBD’s new wide range lambda, so whether they are compatible I’m not sure.
Have they finally got these WRL sensors sorted now?Every time i`ve asked about them i get told that they are still under development:confused:

Al
 

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it's an SPA, and I refer the honourable gentleman to exhibit A.

Exhibits B and C are acceleration meters, not GPS based, but very effective!
 

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Discussion Starter #6
AL said:
Have they finally got these WRL sensors sorted now?Every time i`ve asked about them i get told that they are still under development:confused:

Al
Well no - not quiet yet:(

He has the dyno time booked to do it at the end of this month. He also has all the hardware sorted, but needs the dyno time to make sure it all works togther correctly.

Then we can all hand over our couple hundred quid.
 

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The wide range is much better, use it Giles. The sensor is so much better.

It's quite linear in response to oxygen content in the exhaust. So much so that you can read the actual lambda value from it, rather than just lean, and rich!

A very useful tool, and can then really be used for fuel + ign tweeking :D

:beer:
 

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You want the EGT sensor mounted at the collector or even beside the lambda. On some very expensive toys they have one sender in each header pipe.

On turbo motors its sometimes stuck in the exhaust bell like the lambda sensor sometimes is. As you can imagine it gets very hot here whiel the turbos glowing merrily away.

Capillary water, oil and fuel feeds like Animal said are the most accurate and quick responding. Unless you spend mega bucks. As for the fuel one, I think it will pass an MOT with it inside but its not the most clever idea, if it burts or something then you are gonna get sprayed int he chops with unleaded and if you smoke well that would be intrestring. You can mount it outside the car on the bonnet though, some do that but theres always the chance some twoccers gonna belt it off.

Gearbox oil temp can be handy as well.

Chris
 

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any one thought of developing something to measure turbo rpm?? That would be a very active gauge. Anyone any idea how to do it??
 

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Discussion Starter #11
Hiya Chris. Seen your posts. You seem a very informed man. Where does all your knowledge stem from?

(just being nosey as the things you say are very inetresting).

What does the EGT tellyou then? Is thee an optimum temp and below mean rich, above means lean? Is it the same ideal temp for all engines and exhausts?

What do you think is the best method/s to monitor the engine via exhaust?

TBH I don't really like capillary gauges - the more joints the more places to fail, and I don't really like the idea of fluids inside the car, especially fuel. But is the consensous that capillary is really the only way to go with worth while 'stop the engine now cos it's gonna blow' reaction times?

All gauges are to be nice and tidy in the car as although the engine is race spec the car is only a toy to play with - not just for driving but also for the enjoyment of building/fiddling etc.

Gearbox oil temp - there's an idea. Although I will be only doing a few track days etc so won't be needed all the time.
 

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Why thank you kindly Giles. I do like to thinkI ken a thing or 2 about cars. As for why I know so much its a secret. But I can assure you I am by no means an armchair tuner/mechanic!

EGT sdoes indedd tell you whats going on inside the combustion chambers. And generally hot means lean and cool means rich.

And the temps ary engine to engine, what might be ok for one engine the same temp may burn the valve seats in another for example. So I don't really even want to give a range in case yo ucome back and say "that man killed my engine!"!

The main benifit of them is to make sure the engien nots gonna pop, by picking up a piston or even just burning a hole in it. Also when mapping you can keep the temp at an 'ideal' and make best power.

Cappilaries are the oldest and usually the best kind. ut if you can get the electric ones and are ok with a bit more uncertainty and slower response time then go. Its not like minutes or days in responding a second or so. Put it this way I wouldn't mind having electric ones in my car. Another way to look is its an improvement of what you have at the moment!

Gearbox oil can get surprisingly hot especially if the levels low. You might even find that its time to add fins to the casing (think metro/mini A series sump, BMX boxes and diffs etc) to help keep it cool and extend the life of the box.

Chris
 

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Discussion Starter #13
No probs - Top secret it is then Chris. ;)

You seem to know your stuff - It's the arm-chair modders I weary off - too much 'my mate down the pub said'. - oh so usefull:rolleyes:

- Wouldn't expect you to give figers either, and even if you did it's down to me whether to listen to you. I've always been one to try and get as many (relevant) views as possible then make up my OWN mind. Then the only person to blame is me. :D

I'm gonna ponder the gearbox oil one. I want to strip my box down anyway (partly to install LSD, and partly to check to over), so a quick drill and tap would be easy.

In your opinion what is the best one to have - EGT or AFR? Or is both really the best idea? - after all they be telling me the same thing.
 

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hmmmm... good excuse for another gauge.... Gearbox oil temp!

Ta very much!

PS Us arm chair modders, nothing but trouble!
 

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I experimented with fuel pressure using an electrical sender - after three failed attempts (they replaced each sender) - they eventually admitted their senders should not be used for fuel - the internal seals kept going - the fuel attacked them.

whilst they worked though, it was great - there are others, but I think you'll find they're a lot more expensive than the £30 one I used to use - the Stack one for instance is £80.

So now I compromised and have a fuel compatible 15psi pressure switch on the regulator - plumbed to a warning light on my DIY center console - I figure it's better than nothing - I also did not like the idea of a capillary - which of course are the best, unless you really do spend a hell of a lot - the entry level pressure senders are nowhere near as accurate.

The other thing I pondered about was coolant pressure - overkill probably, as a burst pipe will probably make itself known before you see the light flashing ;)
 

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Discussion Starter #16
humm thanks Gary.

Agree water pressure probably is OTT, especially as I'd expect to see the temp rise when there is a leak.

I'm prepared to pay sensible money for the senders etc as their cost pails into significance compared to what the engine has cost me (& would cost me to re-build). :p

I definatly want to now fuel pressur in car though - my injection fuel pump, swirl pot etc etc is all in engine bay and near the exhaust. If I have a problem I'd like to know about it asap. Also wanna be happy with fuel pressure is most needed - at WOT with nitrous on.
 

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best thing might be to buy an adjustable fuel pressure switch then - then you can set up the pressure, and fine tune the switch to trigger an alarm at the slightest drop :) - a needle dropping slightly isn't probably going to be noticed quick enough to take action - especially if you are indulging in some fun on the queens highway.

the other way would be to rig up a gauge, and then have a separate adjustable alarm which takes the sender input to the gauge - it would have to be a high impedence input though so as not to screw up the matching between sender and gauge - then you can have alarm andpressure - I was going to do this until the blasted sender fiasco.

I've now ceased spending on instrumentation and will go for the full Stack system at some point when I'm feeling suitably frivolous.
 

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Discussion Starter #18
Gary said:
the other way would be to rig up a gauge, and then have a separate adjustable alarm which takes the sender input to the gauge - it would have to be a high impedence input though so as not to screw up the matching between sender and gauge - then you can have alarm andpressure - I was going to do this until the blasted sender fiasco.
This was my preffered option. I would like to have a system where a buzzer and/or light goes when any instructment is outside set limits. - Maybe one day :rolleyes:
 

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Animal your the manta man aren't you? You have a rear diff stick a sender in there to an extra gauge and if I had to choose over box temp or diff temp I would choose the diff.

Turbo rpm? Not really possible, it would have to be inside the inlet/outlet bell and somehow get a rpm reading. You would be surprised at how it would work actually. It would start off slowly build up then gradually tail back off. Around Max torque rpom would be the highest turbo speed.

Max torque is also when the cyl is at its hottest.

Anyway, both if you like gauges Giles! lol In a way they do tell you the same thing to an extent. If I was to choose, probably AFR.

Garys ideas are pretty good. A volt meter at the fuel pump can be usefull to. If the voltage drops so does the flow which isn't good. Fuel pumps have quite a lot of things to fight against you know.

Water pressure a bit much I would think, then again it will tell you if theres a leak (capilary would be great for leakage testing) but it could also tell you if the pump is cavitating. This is when the pump spins to fast and it stops pumping, leaving the engine to thermo syphon. The pressure will rise due to its heating up very quickly and its not good for the engine.

Chris
 

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Was looking at turbo rpm, ideas to do were around using a lazer on the side of the compressor housing to measure time between blades reflecting beam back. Look convincing enough, wondering if any one would think about developing one. Good to tell you turbo response, if bearing start to get old then will respond slower. Any thoughts?? Would be different too
 
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