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View Full Version : My EGT placement ok?


vschaos
10-22-2019, 08:01 AM
http://myweb.cableone.net/kevin65/egt1.jpg
http://myweb.cableone.net/kevin65/egt2.jpg


Basically long story short I am trying to tune my car with megasquirt stand alone. I am just wondering if my EGT placement is too close or not? Yes I know one of my manafold bolts is loose....its becoming a pain :)

I have heard some say its better to put after the turbo or down in the downpipe...... the reason I put it where it is above is because thats where I saw it was recommended to be put. Mainly because the #4 cylinder starves the most for fuel. My issue is that with 40 degrees of timing at cruising speed at 75mph - 80mph I am in between 1400-1500 degrees with a mid 14 a/f. I am wondering if it is too close and causing me to get a higher reading than I should? At WOT with 22 degrees of timing and 18psi on my GT35R turbo with GT40 wheel the EGT's just keep going past 1600+ with ease so I of coarse let off the gas.

slow4dr
10-22-2019, 09:34 AM
I prefer pre turbo installation myself. The only arguement people have that install it after the turbo is if the probe ever came apart it wouldn't destroy the turbo. I've NEVER seen or heard of a probe coming apart.

By placing it where you did it is bound to get hot. By comparison my car is completely stock currently and it will sit at 1400-1500 on the highway and if I stand on the throttle it will go past 1600 easily. The stock tuning will allow for about 1720 so you're fine.

vschaos
10-22-2019, 09:48 AM
I prefer pre turbo installation myself. The only arguement people have that install it after the turbo is if the probe ever came apart it wouldn't destroy the turbo. I've NEVER seen or heard of a probe coming apart.

By placing it where you did it is bound to get hot. By comparison my car is completely stock currently and it will sit at 1400-1500 on the highway and if I stand on the throttle it will go past 1600 easily. The stock tuning will allow for about 1720 so you're fine.

Yea I have heard it has happened before where the probe can break and destroy the turbo yet never actually seen one personally...if it happens I guess it will just happen. So my placement is good? I thought things go bad like pistons and such in the mid 1700's? Thats good to know your 1400-1500 so I nkow I am good. I am averaging 23-24mpg :beerchug: so it obviously cant be running that hot. When I step on it though my EGT's will go all the way to 2k..well I let off when it gets to 1750-1800 and let off. It has climbed to 2k once when I had water injection turned on. All with a 11.7-11.8 a/f.....

slow4dr
10-22-2019, 10:03 AM
Your probe location is fine. :thumb:

Like an oven at home if you put your hand in it for a few seconds no harm no foul, leave your hand in there for 20-30 seconds and your skin will melt off. :fail:

Going north of 1750 for extended periods of time will be excessive especially if you have stock pistons.

vschaos
10-22-2019, 10:15 AM
Your probe location is fine. :thumb:

Like an oven at home if you put your hand in it for a few seconds no harm no foul, leave your hand in there for 20-30 seconds and your skin will melt off. :fail:

Going north of 1750 for extended periods of time will be excessive especially if you have stock pistons.

yup stock pistons and stock head...just 2.0 cams.

Here is a basic rundown of mods....

Megasquirt v3.0 with 4.0 bar sensor
GT35R turbo with GT40 wheel
2.0 cams with fidanza gears
ported exhaust manafold
tubular intake manafold
60mm tb with 60mm plate
4 inch SEE
big front mount intercooler
AGP returnline with bottlekneck fix, -8an feed, 750cc injectors
dual stage water injection M3 and M5 nozzles with 150psi pump
dcr oil pump
dcr windage tray with crank scraper and baffle
balance shafts removed
Autometer NV egt gauge
NGK wideband
Aeroforce scan gauge

What also sucks is that the aeroforce gauge does not read knock :( I never touched the wiring to the knock sensor so in theory I would have thought it would still red knock if and when it became present. To test i revved to 3.5k and had a friend tap the front of block with a wrench to see if it would pick up anything and it didnt.....so now am on the hunt to get something going for a knock sensor with my megasquirt that wont be too painful to setup.

Edit: I plan on saving for motor work to make things safer and make the motor last longer. In the end I only want 450-470whp at the most on pump.

blackbird
10-24-2019, 12:42 AM
The probe failing is about the only reason I can think of for not using it pre-turbine but there's a lot of reasons for not using it post turbine such as slower response times and if you don't also install one pre-turbine at the same time to know how much temp difference there is you really don't know what the EGT's are coming out of the engine. That location you have should work pretty well. It's best but not really practical for a lot of people to install one probe in each runner within a couple inches of the exhaust port. Or if you run one probe to put it into the hottest cylinder (which is hard to tell on your setup without running four probes or carefully reading the spark plugs) or to install the probe in the collector area just before the turbine exhaust housing inlet/collector.

Your temps sounds pretty reasonable. The cruising temps getting up to around 1500 seem a little on the warm side. If you can monitor knock and are watching fueling you might try adding even a little more timing advance under light and no load cruising. The stock EGT's do run pretty high because of the high exhaust backpressure with the stock turbo and is one of the big reasons the factory calibrations run a lot of advance. If you're at WOT and just crossing the 1600's it shouldn't be a big concern if you aren't getting knock. But since you do have a bigger turbo pumping in more air and the cylinder pressures are going to be much higher I wouldn't try to push the temps as high as on a stock turbo.

vschaos
10-24-2019, 07:56 AM
The probe failing is about the only reason I can think of for not using it pre-turbine but there's a lot of reasons for not using it post turbine such as slower response times and if you don't also install one pre-turbine at the same time to know how much temp difference there is you really don't know what the EGT's are coming out of the engine. That location you have should work pretty well. It's best but not really practical for a lot of people to install one probe in each runner within a couple inches of the exhaust port. Or if you run one probe to put it into the hottest cylinder (which is hard to tell on your setup without running four probes or carefully reading the spark plugs) or to install the probe in the collector area just before the turbine exhaust housing inlet/collector.

Your temps sounds pretty reasonable. The cruising temps getting up to around 1500 seem a little on the warm side. If you can monitor knock and are watching fueling you might try adding even a little more timing advance under light and no load cruising. The stock EGT's do run pretty high because of the high exhaust backpressure with the stock turbo and is one of the big reasons the factory calibrations run a lot of advance. If you're at WOT and just crossing the 1600's it shouldn't be a big concern if you aren't getting knock. But since you do have a bigger turbo pumping in more air and the cylinder pressures are going to be much higher I wouldn't try to push the temps as high as on a stock turbo.

Thanks for the info. I am looking at buying Knocksense for my megasquirt and wiring it up for reading knock. I asked the guy from knocksense if I could use my stock knock sensor and he said I should. I dont see why I wouldnt be able to use my stock sensor at all....looks like basically the knocksense unit that he sells just allows you to monitor knock with any knock sensor. Here are some links if you care to look...

http://www.viatrack.ca/
http://www.msextra.com/manuals/MS_Extra_Hardware_Manual.htm#knock

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