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Vanilla Exhaust Pops Replication


#1

I let a friend build a car to see what Automation is like (he’s considering purchasing the game), however strangely this car when ported to BeamNG.Drive haD exhaust pops and crackles, something I thought had to be modded in with JBeam occurs with no file modification whatsoever…

I tried experimenting in the engine designer with a different engine but was not able to reproduce the exhaust pops in BeamNG. A few questions I have…

1.( Was/is this this a feature that was added in a recent update or has it always existed?
2.( What can be tuned (besides JBeam files) to replicate this phenomenon?

Here is the .car file.:
Car_that_pops_-_Trim_45.car (14.2 KB)


#2

It’s a recent thing and comes from running rich (like in reality).


#3

That’s what I figured. Is there a certain “AFR” that triggers these as my test engine was running 12.0 AFR and was still not able to produce the pops.


#4

I’ve done as high as 13.8 and got some pops. I imagine it also takes in to consideration engine cooling too then, and maybe even ignition timing.


#5

After a considerable amount of testing, I have not only been able to reproduce the exhaust pops but may have also found out what parameters the engine can be tuned to in order to reproduce the exhaust pops.

Firstly, I was able to determine that the reason I was not able to get any exhaust pops in the first place was because exhaust flow of the car in BeamNG was not being simulated. I found out that a modded exhaust fixture that I was using was essentially “plugging” the exhaust pipes in beamng, negating any exhaust flow visuals coming out of the tailpipes and thus causing a lack of exhaust pops. Once I removed the fixture or used a different exhaust fixture, exhaust flow became visible and the exhaust was able to produce those sweet sweet flames.

Then, I continued testing engine parameters to determine what caused the engine to produce exhaust pops. What I determined is that the two main engine parameters that effect the likelihood of the engine producing exhaust pops are the AFR and cam profile. My engine was able to produce some exhaust pops at very opposite factors. When I set AFR to its minimum (15.0) and the cam profile to an aggressive setting (~80), the engine produced some pops. When the engine was tuned with a low cam profile (20) and a very rich AFR (~11), the engine produced some pops. Increasing both the AFR and cam profile showed an increase in the number of exhaust pops and visual flames.

In conclusion, for those wondering why their car is not producing exhaust pops, make sure that:

  1. The car has been ported to Beamng from the updated exporter.
  2. The car has visual exhaust flow in Beamng (exhaust flow should be easily visible on the Automation Test Track map).
  3. The engine has either an aggressive cam setting, rich AFR or a combination of both.