Welloilbeefhooked

iTrader: (3)

Hello all,

Just about to fit my EGT Guage and Sensor and was wondering what sort of EGT's I should expect or be aiming for. The 2 conditions I am intertested in are:

1) WOT and full 1.4bar boost

2) 70Mph cruise, 3.5krpm

Cheers,

Wayne.

Welloilbeefhooked

iTrader: (3)

I'm looking for the petrol EGT's so that I can compare them with LPG EGT's

STiFreak

iTrader: (4)

From what I have read elsewhere:

Cruise 700C to 800C
On Boost / WOT keep EGT's below 900C

these must be measured before the turbo.

Welloilbeefhooked

iTrader: (3)

Cheer for that.

I'm mounting the sensor in the Lambda boss on an old set of headers I have. Seems that either here or in the up pipe looks to be favourable. I know the risks of damaging the turbo if the sensor breaks, but how often does this happen with a quality sensor?

Wayne.

STiFreak

iTrader: (4)

In the manifold collector or uppipe seem to be the preferred locations. I have not heard of anyone who has trashed a turbo because of an EGT sensor loosing bits. I am sure it is possible, but these sensors are designed for harsh conditions and I would think the actual likelyhood of this happening to be very slim.

frayz

iTrader: (7)

I have mine mounted 2" below the turbocharger in the uppipe.

At full load WOT in top gear i dont want to see anything over 900 deg c with stock valves.

swisstonihasher

I've had EGT for couple of years now in uppipe, only problem I had was probe failure (by that the electrical connection of types within the probe itself went, so no signal from it), changed from 4mm diameter probe to 6mm probe as its more reliable and lasts loads longer but is a little slower to respond to temp spikes.

When I had a bad map, I was seeing temps of 930 deg on max boost of 1.5 bar...lucky enough noticed it straight away and lifted off quickly, also engine smelt real hot after every run (not funny on a newly built 2.5 engine). Ended up getting it sorted and now see temps of 600/700 ish on cruise and 860's on full chat and that's with 1.65 bar boost! (I do have water injection, FMIC etc which prob helps, plus its all to do with fuel/timing maps). Soon to have her mapped again with hopefully 1.7 bar boost, will update EGTs then - pump will be changed again for motorsport version.

harvey

iTrader: (48)

Location is important as readings after the turbo are lower and dampened down.
I use 930 C as a maximum and have well below 800 C in the cruise at 3.5 to 4.5 K rpm.
I have damaged at least two turbos with EGT tips breaking off.

Welloilbeefhooked

iTrader: (3)

Yesterday I did a few tests as shown below taken from my other post.

"Today I got my Dyno Tune EGT gauge and sensor up and running.

The probe is mounted in the ported OE headers that I have in the same location where the lambda sensor would be on the early cars, so just before the up pipe.

I have reset my LPG ECU and set it up with only an autocalibration to see how far this is out from what is required.

I have 2 boost settings in my AVCR at the moment, 1bar flat and 1.45 taling off to 1.25 at 7k RPM.

My LC-1 wideband sensor and gauge were recalibrated before the testing.


First test was a full temperature cruise at 3.5k RPM in fifth gear.

At the same load the petrol reads 750c and the LPG reads 730c. This is with an AFR of 14.7 on both fuels. The AFR settings in the LC-1 were left on petrol.

The next test was a 1bar run in 4th gear.

At 6k RPM on petrol I have EGT's of 927 with an AFR of 12.2

At 6k RPM on LPG I have EGT's of 845 with an AFR of 10.9 (So the LPG needs trimming)


Even though I'm not testing the higher boost setting yet the petrol EGT at 6k RPM is 950 with an AFR of 11.2.

At idle after a good run I have 450c on petrol and 435c on LPG.

So, unitl I get the LPG mapped to the same petrol AFR at 1bar boost I'm leaving the higher settings alone.

From previous logs my IGN timing at 1bar on petrol is around 25-26 degrees.


What are peoples thoughts on the EGTS and AFRS shown above?

The 1 bar boost area is part of the map done by my mapper a couple of years ago and nothing has changed since.

Wayne. "

harvey

iTrader: (48)

I would expect gas to run cooler than petrol but I would expect the target AFR for gas will be different to that for petrol so ask some gas specialist what your target AFRs should be for gas. 950 C. at 1 bar is way too hot. Can you add any more ignition? If not, add some more fuel.

Welloilbeefhooked

iTrader: (3)

Harvey,

I'm a bit confused about the AFR's of gas as I thought that if I have my wideband showing 14.7-1 at lambda then it will also show 14.7-1 on LPG at lambda? LPG is 15.8-1.

Afaik the LPG ECU simply tries to inject the correct amount of gas to match the petrol AFR's. The guys at TinleyTech who supplied the kit have also said that I should see the same AFR's on LPG as I do petrol and have never mentioned any other values. I will go back and check though just to be on the safe side.

Do you think that the gas temp is probably of more use to me than the AFR's?

I am going to try some more ignition to see if I can get the temps down, 1 degree at a time.

Last thing and probably my fault, the 950c was seen at the 1.4 boost setting.

Wayne.

Welloilbeefhooked

iTrader: (3)

Ok, tried more fuel with good results. Petrol only for this, no LPG.

11.2-1 at 1.25 bar makes for 890c and 10.8-1 makes for 840c

Will put the fuel back as it was and try the ignition tonight and then start altering both to suit.

I think that I may have a problem with my MAF as when it rains I get a very rich AFR of around 10.2-1 at idle and on cruise. How do I check that the MAF is ok as I think it is beginning to lean out the fuel.

Wayne.

harvey

iTrader: (48)

I have no knowledge of what you should be aiming for with gas but I know that the most efficient fuel burn (Lambda) varies with the type of fuel used so, while 14.7 is your off boost lambda target for petrol you need a lower lambda target for oxygenated fuels and for methanol/toluene/xylene mixes you can estimate the lambda to aim for depending on the percentage fuel mix if you know the lambda for each fuel used
Adding some fuels will lower the burn temperature, just like adding water and I would guess that gas has this effect but your gas specialist can confirm this and suggest target AFRs and EGTs.
The EGT is a very good indicator of how the engine is running. I expect to run around 900 C flat out to allow for variations/fluctuations but I never want to exceed 930 C because I know that damage can occur a short way past that from previous expensive experience. I know of others who have run 950 C and higher but with guage fluctuations and the inherent variables in the process I stick to my 900 target max and 930 Tne.
Adding fuel obviously reduces EGTs.
Remember that adding ignition MAY also reduce EGTs but you need DET cans and monitoring to ensure that you do not go to far and run into DET and goose the pistons etc.
Different exhaust valves made from the right type of material will allow the EGT Tne to be extended.
Generally the engine produces more power with the higher EGTs but your mappers cannot map like that on customer cars as it is too close to the edge and there would be a lot of engine failures so they add more than optimum fuel for power as a safety factor.
Apart from that, a good quality EGT guage is expensive and another complication so not many people run them. On some high performance cars and on aero engines an EGT guage is part of the basic kit.

Where is your air filter located?
If your MAF is U/S and you take the plug off the sensor connector, the engine MAY stop on a Classic. I think this is a probable indicator of a MAF failure. Someone else can perhaps give more info on identifying MAF failures.
I run Simtek and Motec so have no use for the MAF Sensor which as far as I can see is an Achilles Heel, especially on M/Y99-00 and exceptionally expensive on later M/Y cars.

Welloilbeefhooked

iTrader: (3)

Harvey,

Thanks for the detailed response. I think that my concerns of the high temps may be nothing other than reading from a cheapish gauge and sensor. After all, Andy mapped it years ago and I have never head any running problems. I'm probably being over cautious due to the LPG running still being fairly new and my first attempt.

Cheers,

Wayne.

harvey

iTrader: (48)

Here are photos of my uppipe. In fact there are four uppipes and I tailor each uppipe to the customers requirements and model year bearing in mind the specification and turbo in use.
These retail at £139 inclusive of the heat wrap and 5 new studs and Paypal, with overnight delivery on top.

Welloilbeefhooked

iTrader: (3)

Might just be having one of these up pipes.

Just another thought about the EGT's. I have reduced the plug gaps to 0.55mm as the LPG runs better with smaller gaps. Would smaller gaps make for a higher EGT?

Wayne.

harvey

iTrader: (48)

I honestly do not know but having thought about it I doubt that reducing the plug gap could have much effect on temperature. It may marginally reduce power.

Welloilbeefhooked

iTrader: (3)

Found the problem with the MAF!! The rubber o ring was goosed!

Apart from it being as flat as a pancake it was missing a section so was leaking air.

I would imagine that this would cause lean running as I have just logged against my new map settings and now found that I am running richer than required at the top end (10.5-1). EGT's down to 890c on 1.25 bar at WOT 6kRPM.

At least all is now well.

Wayne.