MAT location question

[Hof360]

Hi Everyone,

I have been reading over and over about MAT placement and how it affects the charge air temp etc. even got on to the Ideal gas Law and the Density of air on WIKI.

I recently had some Dyno time and seemed to get my VE's within the ball park at running temps and suprise, suprise, when I went to take the car home the next day, cold afr's were way off... and could barely drive it until it was nearly up to temp.


I have narrowed it down to my charge air temp table's ie. %coolant contribution and charge temp inverse temp term

I have used the %coolant contribution from standard 12P Bin and the charge temp inverse temp term from the VK355 bin.

I have my MAT sensor in the underside of a 14" chrome aircleaner mounted to a 4 barrel Throttle body and not in the Intake runner as it would have been in a buick/GM type manifold. (this is a Chrysler 360)
MAT temps only ever see a maximum of 44deg Celsius.

I have tried to tweak the charge temp inverse temp term but it only uses about 4 of the cells for the complete running range. although I did get it to start cold and run, I'm not happy with the VE table.


My questions are,
-Has anyone successfully run a sensor that far upstream?

-If so how did those tables look? (I'm assuming nothing like anything from a factory BIN)

-given how much my afr's vary on the wideband have I wasted my time on the dyno?

Cheers,

Luke

[vlad01]

Yeah have run them in the plenum a few times on a v6, and with stock tables were way more stable than factory ironically to the point nothing was needed to be changed for the charge temps.

Had more issues with stock factory setup and heat soak to be honest and is something that can't really be tuned out, only slightly improved. Moving it upstream actually overcome the issues as it got around the scenario of coolant temps dropping while MAT increasing after a hot restart, but still on the bulk of the manifold were it still warms up with the engine and represents incoming intake air temps.

So for a ecotec v6 in the plenum was way better than the lower runner from the pre ecotec it came from, simply because of this heat soak issue.

Also with some engine configs there is exhaust gas reversion into the intake at idle, so within 30 sec of idling the MAT temps are pegged at max value of 150C, in reality it would be even higher, wouln't be surprised if the gas temps were 200+

So I reckon from my personal experience, high in the runner or plenum is best.

[VX L67 Getrag]

O.K. so as we know EVERYTHING is critical....
In saying that on a N/a setup youre trying to get that extra 1-5%.... it really doesn't matter. In saying that closer to where the fuel is introduced would be best but how well is the software to react to that in "THAT" setup???
So in N/a setup it is only helping slightly for a slight help in everything, but in forced induction setups it's a LOT more critical... but going off tpic as it's not what you asked!

So short of my response is depending on placement will depend on how well it's been setup to respond!

[Hof360]

My concern is that my %coolant correction table is really going to need work, and what is the best way to get this right?

I feel that I have poorly tuned my VE Table because my original %coolant correction table didn't match my application.

It also seems that in my case, using the Charge temp inverse temp term to get this right is not the answer and maybe that should just match the actual MAT temps.

FWIW I am chasing some pretty large AFR variations here not just 1-5%

Thoughts??

[immortality]

Yeah have run them in the plenum a few times on a v6, and with stock tables were way more stable than factory ironically to the point nothing was needed to be changed for the charge temps.

Had more issues with stock factory setup and heat soak to be honest and is something that can't really be tuned out, only slightly improved. Moving it upstream actually overcome the issues as it got around the scenario of coolant temps dropping while MAT increasing after a hot restart, but still on the bulk of the manifold were it still warms up with the engine and represents incoming intake air temps.

So for a ecotec v6 in the plenum was way better than the lower runner from the pre ecotec it came from, simply because of this heat soak issue.

Also with some engine configs there is exhaust gas reversion into the intake at idle, so within 30 sec of idling the MAT temps are pegged at max value of 150C, in reality it would be even higher, wouln't be surprised if the gas temps were 200+

So I reckon from my personal experience, high in the runner or plenum is best.

I'm sorry but how is this relevant? The OP is talking about a 360 with a MAT sensor fitted into the base of the aircleaner above the throttle body. A much closer proximation would be a ecotec with the AIT sensor fitted in the airbox.

The ecotec plenum still sees a fairly large change in temps and does still suffer from heatsoak in the standard application even when fitted with the MACE spacer/insulator.

The OP would ideally need to fit the MAT sensor either into the plenum or one of the runners to be closer to what you are suggesting with your ecotec plenum example.

[Hof360]

logtowarm14july18.xdl

A log file to warm

(670.55 KiB) Downloaded 366 times

chargetemp monitors.adx

ADX used to monitor Charge temps etc

(79.28 KiB) Downloaded 355 times

cold start edit.bin

Current Bin Based on 12p V8 BCLF

(32 KiB) Downloaded 379 times

[Hof360]

Yeah have run them in the plenum a few times on a v6, and with stock tables were way more stable than factory ironically to the point nothing was needed to be changed for the charge temps.

Had more issues with stock factory setup and heat soak to be honest and is something that can't really be tuned out, only slightly improved. Moving it upstream actually overcome the issues as it got around the scenario of coolant temps dropping while MAT increasing after a hot restart, but still on the bulk of the manifold were it still warms up with the engine and represents incoming intake air temps.

So for a ecotec v6 in the plenum was way better than the lower runner from the pre ecotec it came from, simply because of this heat soak issue.

Also with some engine configs there is exhaust gas reversion into the intake at idle, so within 30 sec of idling the MAT temps are pegged at max value of 150C, in reality it would be even higher, wouln't be surprised if the gas temps were 200+

So I reckon from my personal experience, high in the runner or plenum is best.

I'm sorry but how is this relevant? The OP is talking about a 360 with a MAT sensor fitted into the base of the aircleaner above the throttle body. A much closer proximation would be a ecotec with the AIT sensor fitted in the airbox.

The ecotec plenum still sees a fairly large change in temps and does still suffer from heatsoak in the standard application even when fitted with the MACE spacer/insulator.

The OP would ideally need to fit the MAT sensor either into the plenum or one of the runners to be closer to what you are suggesting with your ecotec plenum example.

Thanks Immortality, My thoughts exactly. (not having a shot at vlad, everyones input is valued)
My MAT sees a Maximum of 44-46 degrees this time of year, and gets 'heat soaked' up to about 56 degrees on warm shutdown.

I was hoping someone had tuned these tables with a similar placement of MAT sensor.
I believe Dylans VK355 tune was a COME TTB manifold, Where did these have the MAT sensor?

[immortality]

I believe the COME TTB manifold has it in the stock location (base of the runner) but in runner number 8.

On the stock tune the MAT sees huge temps changes, in your location it won't so the table will off heaps.

[Hof360]

I believe the COME TTB manifold has it in the stock location (base of the runner) but in runner number 8.

On the stock tune the MAT sees huge temps changes, in your location it won't so the table will off heaps.

Yep Agreed,

now i just have to work out a Fix

Move the sensor or tune accordingly?

[immortality]

I'd suggest moving it so it sees more realistic temps and then tune to suit.