12 replies to this topic

[LumpyVR4]

My long term plan as far as tuning for my car is concerned, is to run DSMlink. To do this I obviously need sensors to tell me what is going on in the engine so I can get the maps right. I am trying to decide whether it is worth it / necessary / best practice to have an EGT gauge as well as a WB o2 sensor (which is a given) to get the tune on the car to its best, or should I spend the money on an EGT gauge on something else. Any comments based on previous experience appreciated.

[DOUGMO]

I would for sure, ideally you would have 1 in each runner of the manifold but 1 in the dump
still gives you an idea of the tune even if the mixture is ok

[MDK87]

Dougmo, I'm a noob when it comes to EGT tuning.

How do you know what you should be expecting? 

Unlike AFR, temps would need to change a decent amount with load.

Also say you're using a flex fuel setup, are the target temps different for different fuels?

I'm guessing cam overlap would have some effect on EGT as well. And then you have things like water/meth injection.

I was always interested in it but didn't know enough about how to best use it especially given the many variables at play mentioned above.

I came to the conclusion that it would only be useful to check that EGT's aren't unbalanced between cylinders but this caught my attention - "1 in the dump

still gives you an idea of the tune even if the mixture is ok "

Do you have EGT monitoring installed in your car?
I'd like to know more about it.

 

Don't mean to hijack but I figured this could be useful to the OP aswell.

Edited by MDK87, 17 August 2014 - 01:30 AM.

[DOUGMO]

yes temps vary a lot with fuel used. to give you an idea I used to see 850c on pump 98, I now see mid 600s on e85.

its especially good for tuning e85 as you can judge the right amount of timing to use, too little and the temps are very high, add timing and it will drop, if you have too much it will go up again so you can find the sweet spot because you wont get det warning early enough on e85

[MDK87]

Ahh ok yeah I've heard that tuning for timing advance can be tricky with E85. 
And that's a BIG temperature drop going from premium!

Cheers mate.

[DOUGMO]

yeah e85 is awesome for keeping everything cooler.

[LumpyVR4]

yes temps vary a lot with fuel used. to give you an idea I used to see 850c on pump 98, I now see mid 600s on e85.

its especially good for tuning e85 as you can judge the right amount of timing to use, too little and the temps are very high, add timing and it will drop, if you have too much it will go up again so you can find the sweet spot because you wont get det warning early enough on e85

 

OK I'm pretty much sold on putting EGT in my dump pipe as close to the turbine as I can manage. One thing I have noted in my reading is that no one can tell you what is a good or bad/dangerous temp because it varies from car to car. I'm fine with that, but how do you then figure out what is good or bad for your car? Do you vary the timing for lowest temp / no knock like you mentioned for E85?

Edited by LumpyVR4, 17 August 2014 - 04:25 AM.

[DOUGMO]

I had low timing and then watched the temp drop as timing increased, you will find the sweet spot,as I said mine sits around 600-680 on the track on e85

Edited by DOUGMO, 17 August 2014 - 07:02 AM.

[LumpyVR4]

I'm going a little off topic, but it's my thread. Is there any reason to not tap the EGT probe into the turbine housing near the exit to the o2?

[DOUGMO]

nope, I had that originally, I now have it in the dump as I have a twin scroll

[bazeng]

Egts are slow and in my opinion not really required as a single unit after the turbo at it will only measure the hottest cylinder...

Ideally you would want 4x egt, one per cylinder. . This in conjunction with your wideband will give you two things..

1. Individual cylinder details (if one cylinder is not the same temp as the others (approx numbers) you can identify which cylinder and isolate the problem.
2. Once balanced, you can be confident that the o2 readings are across all cylinders.

Best config is to have 4xwbo2 sensors, 1per cylinder. ..

Edited by bazeng, 23 August 2014 - 09:10 PM.

[DOUGMO]

100% agree baz, but you also need an ecu with individual cylinder trim too make that useful

[DOUGMO]

100% agree baz, but you also need an ecu with individual cylinder trim too make that useful

I would for sure, ideally you would have 1 in each runner of the manifold but 1 in the dump
still gives you an idea of the tune even if the mixture is ok