Safe EGT limits

[Nightstalker1993]

Hi guys, I'm currently running an MS3x on my Proton Waja with a Mitsubishi 4g18 Bolt-on turbo setup, self-tune OTR at 0.8-0.9bar boost. I have an EGT probe setup at the collector right before the turbo and sometimes at 4th gear pulls around 5500rpm, my gauge alarm will go off at the preset value of 900c and I'll lift-off throttle. Is 900c at the collector a cause for concern or am I being too paranoid? AFR at that boost level is 10.5-11 so I don't think I can go much richer and from my research with Google, most people quote max EGT numbers when the sensor is at the runner around 900c, but my probe is at the collector.

According to here, when the probe is at the collector he got 870c but when he placed the probe on the runner he only got 760c so having the probe at the collector will get temp readings on average 100c higher than the runner.

Another thing I would like to ask is that, since the thermocouple is basically a millivolt-generator of sorts, can I parallel wire it to a seperate thermocouple amplifier to feed the data to the MS3x instead of running multiple thermocouples for the gauge and ECU.

Thanks guys!

[nathaninwa]

Could timing be a little retarded?

[Nightstalker1993]

I'm kinda afraid to advance it anymore, nowit's 13-16.6deg at 4500-6500rpm and I remember last time when tuning, this is roughly 4-5deg away from severe knock and since I haven't gotten a working knock sensor yet,I tuned it quite conservatively. I'll post an msq later.

[Nitroking]

I wouldn't be afraid to see even 950C before turbo but that's it, no more. I currently have around 730C on the downpipe right after the turbo at 1 bar and the only way to see higher is to cruise at 180kmh for 20 minutes or more.. But if I go WOT, there it goes again,around 730C.. AFR is 11.5-11.8, ignition around 21-22deg, engine compression ratio 8.5:1 forged B6 Miata..

What are your engine specs?

[Nightstalker1993]

I wouldn't be afraid to see even 950C before turbo but that's it, no more. I currently have around 730C on the downpipe right after the turbo at 1 bar and the only way to see higher is to cruise at 180kmh for 20 minutes or more.. But if I go WOT, there it goes again,around 730C.. AFR is 11.5-11.8, ignition around 21-22deg, engine compression ratio 8.5:1 forged B6 Miata..

What are your engine specs?

I just increased my gauge alarm threshold to 930C instead, I think it was just peaking at slightly above 900c previously. So with 730c at the downpipe, you reckon the turbine inlet temperature to be around 950c or so?

My engine specs are as follows
- Mitsubishi 4g18 engine (1.6L, despite the engine code)
- Proton CFE(turbo, non-forged) pistons
- Measured and calculated 8.8:1 CR
- JASMA(cheap local stuff) 272" cams but not much overlap as the idle is pretty smooth but measured higher lift
- TD04L turbo from a Subaru
- 0.8~0.9bar boost

I've got a friend who's running a 5efte engine with forged pistons getting a reading of 900c at the downpipe after a cam upgrade, reading before this was 800c only, I wonder what are the turbine inlet temperatures. He had been running it for a few months now but he doesn't push the car that often.

[Nightstalker1993]

http://www.youtube.com/watch?v=UaYGb4CgL_w

Here's a video to my most recent run where the EGT alarm was activated.

[Ign Adv Deg] [Injector Duty] [RPM] [GPS Speed] [AFR] [MAP] [TPS]

[Nitroking]

Hello,

No I don't think that the turbo inlet will be more than 880-900 while 730 at the downpipe..

There are some stuff that are relevant, I was going to say about the cams and then you mentioned the 5EFTE.. The higher overlap (than stock) is probably the case for the higher EGTs.. Plus I guess that SOHC cars get hotter than DOHC engines..

[Michael]

With regard to paralleling your thermocouple to gauges and MS. I would recommend you feed your thermocouple to the thermocouple amplifier and then feed the output from the amplifier to your gauges and MS. The wires used to connect to your Thermocouple, assuming it is a Type K are dissimilar metals: Cromel and Alumel. These metals must be used for all thermocouple connections prior to the amplifier. If you were to use, say, ordinary copper wire to go from the T/C direct to MS this would form a "cold Junction" which will introduce an error approximately equal to ambient temperature in your readings. Furthermore, as the voltage generated by the T/C is so small, it may get dragged down introducing more errors.

Michael

[Nightstalker1993]

Hello,

No I don't think that the turbo inlet will be more than 880-900 while 730 at the downpipe..

There are some stuff that are relevant, I was going to say about the cams and then you mentioned the 5EFTE.. The higher overlap (than stock) is probably the case for the higher EGTs.. Plus I guess that SOHC cars get hotter than DOHC engines..

Well currently I leave the alarm threshold at 930c instead and also just updated to the latest firmware from my dinosaur 1.2.4. Enabled High Power Time Enrichment which should solve my problem as I'm only getting alarm triggers during extended boosting(4th gear or 5th gear)

With regard to paralleling your thermocouple to gauges and MS. I would recommend you feed your thermocouple to the thermocouple amplifier and then feed the output from the amplifier to your gauges and MS. The wires used to connect to your Thermocouple, assuming it is a Type K are dissimilar metals: Cromel and Alumel. These metals must be used for all thermocouple connections prior to the amplifier. If you were to use, say, ordinary copper wire to go from the T/C direct to MS this would form a "cold Junction" which will introduce an error approximately equal to ambient temperature in your readings. Furthermore, as the voltage generated by the T/C is so small, it may get dragged down introducing more errors.

Michael

Hi, thanks for the insight but just to clarify, you mean there is a thermocouple amplifier which can output 0-5v for the ECU AND another output which gives the same millivolt level as the thermocouple to feed into my gauge? Meaning one 'amplified' 0-5v calibrated output and another 'pass through' voltage for the gauge? Or you're meaning something else entirely?

[Michael]

No, Sorry. I was suggesting, wrongly, that you feed your thermocouple to the amplifier, then take the 0-5v output from the amplifier to both your gauge and the MS. I hadn't realised that your gauge used the raw thermocouple (mV) output. I think that if you don't want multiple thermocouples, you should try your original suggestion and parallel and parallel the gauge and amplifier input - it won't harm anything. There will either be a wild discrepancy between your gauge and the MS reading or they will be close. it will depend upon what accuracy you need and if you can dial out any inaccuracy on your amplifier.

Michael

[Nightstalker1993]

No, Sorry. I was suggesting, wrongly, that you feed your thermocouple to the amplifier, then take the 0-5v output from the amplifier to both your gauge and the MS. I hadn't realised that your gauge used the raw thermocouple (mV) output. I think that if you don't want multiple thermocouples, you should try your original suggestion and parallel and parallel the gauge and amplifier input - it won't harm anything. There will either be a wild discrepancy between your gauge and the MS reading or they will be close. it will depend upon what accuracy you need and if you can dial out any inaccuracy on your amplifier.

Michael

After doing some research, I think I might just abandon plan on the paralleling and just get a 4ch one and install individual EGT sensors on each runner after factoring cost, ease and end result. 4ch for cylinder trimming, datalogging of temps and the existing gauge would be to monitor overall temps.

Currently the cheapest option I can see for the 4ch amplifier that can interface with our MS3 is this

http://www.piilix.fi/webshop/catalog/pr ... ucts_id=37

Are there any other options? This product is designed to give a calibrated 0-5v output, perfect and easy installation on MS3x. The Innovate TC-4, as far as I know, cannot communicate with the MS3x directly.

[racingmini_mtl]

Yes there are other options. This is one: http://www.diyautotune.com/catalog/cane ... p-542.html

Jean

[Nightstalker1993]

Yes there are other options. This is one: http://www.diyautotune.com/catalog/cane ... p-542.html

Jean

I don't need 8 channels, and that costs literally 4x more!

[racingmini_mtl]

Unless I'm not seeing the correct thing, what you linked to is a single channel. You need to multiply the price by 4 if you want 4 channels. So it is the same price.

Jean

[Nightstalker1993]

Unless I'm not seeing the correct thing, what you linked to is athe ngle channel. You need to multiply the price by 4 if you want 4 channels. So it is the same price.

Jean

Ahh crap no wonder it was so cheap... Must had confused myself when I was searching for the other 4ch egt amplifier. Anybody had success with diy 4ch egt amplifier with arduino parts? the costs seems to be cheap and can program an external display to be used as a gauge as well in addition to an external output

[Nightstalker1993]

any comments on this?

http://www.ebay.com.my/itm/Thermocouple ... b#shpCntId

probably gonna use it for this

http://www.ebay.com/itm/EGT-Thermocoupl ... 3a6d1ab45a