concensus of running EGT's

[Me78569]

My EGT's are down about 50 - 100*f when cruising with the new quad tuning.

[AH64ID]

That sounds like a lot of timing!!! 

 

I've played with my cruise timing and never see that much of a change to EGT's with the amount of timing change I am comfortable with. 

[Me78569]

Timing tables are the same, 

 

It is the power reduction below OEM curve when at low boost that is making the difference.  

[AH64ID]

40 minutes ago, Me78569 said:

Timing tables are the same, 

 

It is the power reduction below OEM curve when at low boost that is making the difference.  

 

Not sure I follow???

 

Tuning doesn't change the hp/tq requirement to cruise at a certain speed. Changing the curve just puts you in a different part of the curve as the same power is physically required. 

[Me78569]

You are assuming that the tune that is running is not overfueling due to outside variables. and that the tune was exact enough to handle low load fueling efficiently. 

 

 

I have no idea if my MPG is up or not, but my cruising EGT's are down since I am no longer bound by the old quad maps.

 

 

 

 

I do understand your thought process also as I was sceptical myself starting out.  However the same held true when I would change power levels before also.  Higher egts when I had the box turned up.

 

This was not true with stock injectors however.  Only after then larger injectors.

Edited August 1, 2016 by Me78569

[TFaoro]

My peak egts have dropped some (it seems) since the quad isn't overfueling before the turbos spool. Last data log was 1528* where before is could have been in the mid 1600s or more. It was about 84* ambient, so I'll just have to do more testing. Not sure about cruising yet as @Me78569 keeps making me put my foot to the floor!

[AH64ID]

From a tuning standpoint you aren't overfueling at cruise... that's not really possible. You can overfuel on acceleration or WOT but not cruising. If you were to overfuel in a cruise scenario you would accelerate and thus not be cruising. Make sense???

 

So it still doesn't describe how steady state EGT's are down without a timing change. On a single injection event ECM, without pressure control, the only real way to effect EGT's steady state is timing. 

 

It's fun looking at the differences that emissions and knowledge (time with system) made in the early vs late HPCR 5.9 tuning. Different tables and different names for tables really stick out. 

 

The early timing was in 2 tables which were steady state and transient (just like VP44 tables), whereas the late HPCR had 5 timing tables. Most of that was for emissions but what I find interesting, especially with this topic, is they completely dropped the steady state and transient labels and instead focused on air density and intake temp. 

 

Tyler... are you peak EGT's at mid rpm or high rpm? Or rather.. were they?

 

 

Edited August 1, 2016 by AH64ID

[TFaoro]

8 hours ago, AH64ID said:

From a tuning standpoint you aren't overfueling at cruise... that's not really possible. You can overfuel on acceleration or WOT but not cruising. If you were to overfuel in a cruise scenario you would accelerate and thus not be cruising. Make sense???

 

So it still doesn't describe how steady state EGT's are down without a timing change. On a single injection event ECM, without pressure control, the only real way to effect EGT's steady state is timing. 

 

It's fun looking at the differences that emissions and knowledge (time with system) made in the early vs late HPCR 5.9 tuning. Different tables and different names for tables really stick out. 

 

The early timing was in 2 tables which were steady state and transient (just like VP44 tables), whereas the late HPCR had 5 timing tables. Most of that was for emissions but what I find interesting, especially with this topic, is they completely dropped the steady state and transient labels and instead focused on air density and intake temp. 

 

Tyler... are you peak EGT's at mid rpm or high rpm? Or rather.. where they?

 

 

I agree with your first statement. @Me78569 I bet you are seeing lower egts because of the throttle position. It likely has higher timing in that position on the map, so it's dropping temps. Try switching your high idle switch to a cold temp and see if they come back up...

 

As for my egts they start to spike around 2200rpm or so, then fly up from there. I think it's because the primary housing is so tight it's making really high backpressure and not allowing the secondary to pull as hard as it should.

This morning I passed a couple people with a 1200us pulse. I laid into it at about 55mph, peaked at 95mph, 62psi of boost(maxed the MAP sensor), and 1734* on the egts. Someday I'll get a new housing on the 75.

[AH64ID]

Wowza... that's warm :-)

 

I didn't realize the 2nd gen MAP sensor went so high.

[TFaoro]

8 minutes ago, AH64ID said:

Wowza... that's warm :-)

 

I didn't realize the 2nd gen MAP sensor went so high.

Yeah... much hotter than I'd like it. The quad maxes in the mid 1800s, and I've pegged it a couple times. Really need to work on that.

 

I was surprised it went so high too. I may look at relocating mine, but we'll see.

[Me78569]

You guys are likely right,  my APPS is about % higher than it used to be.   The only thing timing wise that could be changed would be the oem timing as the quad's map's would be the same.