General Engine Sensor Question

[lts1ow]

This is for my gas bullet, so wasn't sure where to stick the thread.

For an IAT sensor, I was gonna stick it in my carb spacer, thoughts on that?

And then for meth, spray it before or after a MAF?

Figured I would ask you guys cause a turbo diesel has the same sensors :thumb:

 

[chevyburnout1]

A lot of factory cars have the IAT sensor just in the air box or a little before the intake. Not sure how your air filter is setup on the car. And spray the water meth after the MAF or it will skew the air flow readings horribly.

 

[lts1ow]

Sorry, its a turbo engine (hence me asking here:thumb

So basically, would keeping the IAT in tube pre throttle body be any different than sitting post throttle body in between intake elbow and single plane. Obviously you would see highly temps, but to the engine it wouldn't matter as long as the tuner was aware of the IAT placement is my thinking.

 

[chevyburnout1]

I caught that after I posted. I would think post intercooler (if equipped) would be most beneficial for data and the tuner.

 

[McRat]

Tuning for performance isn't always the same as tuning for emissions.

The IAT should be pre-cylinder head, post intercooler, but isolated from heat sources. ie - not screwed directly into aluminum that gets hot. You want to know the temp of air going into the cylinder.

Dry nitrous is sprayed pre-MAF, but that is air. Not sure you'd spray water or meth pre-MAF since it's not. I'd assume you'd spray water/meth post-intercooler to avoid puddling.

 

[lts1ow]

Ok thanks guys, guess I gotta drill and weld my charge pipe.

Another question, do duramax engines come close to maxing out the MAF? If so, whats done then, speed density tune?

 

[McRat]

Diesels don't care about AF ratio. The MAF is only for emissions. Some people run without them.

 

[lts1ow]

Ach, right ok

 

[McRat]

Something to note about OEM MAFS's, they are sensitive at low air flows but not at high airflows. This is deliberate. The EPA testing is done at low airflows, so they aim the sensors resolution towards the bottom.

This is why so many digital controlled OEM engines do not use the MAF for WOT operation. It goes by a fixed table instead based on calculated airflow, not measured.

 

[lts1ow]

Yea, I will be close to if not maxing out my planned MAF, worst case just switch it to a straight SD tune, just trying to hold onto the last shreds of a "street" car

 

[DuramaxPowered]

Are you a member on theturboforums.com?

 

[lts1ow]

Nah, I mainly stick with 4th gen specific boards. I get made fun of for owning a LT1 and not an almighty so awesomeness LS1

 

[McRat]

Yea, I will be close to if not maxing out my planned MAF, worst case just switch it to a straight SD tune, just trying to hold onto the last shreds of a "street" car

This is what I'm saying, even with a closed loop ECM, it goes mainly off the a Fuel Enrichment table that adds extra fuel, the MAF is not accurate at WOT. You adjust that table on the dyno at first, then fine tune it at the track. You read the O2 sensors and the plugs, and aim at about .88 volts at WOT, and tan plugs, with no knock. Late heads don't take a lot of timing, about 22-25 deg naturally aspirated. Less if boosted.

 

[lts1ow]

I shudder at making any attempt at reading plugs with these headers.

Its getting tossed on the dyno and they can get it as close as they can, then its just enjoy it time. :rofl:

Same guys did my friends F1a tune and I change the plugs on that, they were decent. We shall see