gutless 01

[SupraTuRD]

Rob, how many runs did you make with the deck plate removed? If only one pass was made, I'm wondering if the ECU was trying to learn and make changes to compensate for the additional air. Perhaps it needed more time to learn?

 

[bamachem]

If I were to take it further I would try and use a tuned velocity stack to help bring air in. I'm no expert in air flow and thermal dynamics though. I may sit down with a ME friend of mine and model it, just for giggles....

Just picking a little, but it's Transport Phenomena, not Thermal Dynamics. TP is what you would use to derive a flow equation from a Bernoulli base in order to predict the flow characteristics based on the surfaces interacting with the air. However, proper and accurate derivation of the equations for turbulent flow takes some serious computing power. In the end, it just wouldn't be worth it for a 5hp MAX increase from an airbox modification. Determining useful flow equations for laminar fluids over flat surfaces is a graduate-level course in Mechanical and Chemical engineering. Jumping to turbulant flow in a geometric box is some serious PhD reasearch study stuff...

In other words, trial and error tesing is MUCH more productive, MUCH quicker, and MUCH cheaper.

However, the tone really is nice. If you liked the open airbox, you should hear it with a straight piece of stainless in place of the OEM resonator intake.

Thanks again for your professional review of all this.

 

[OregonLC]

To bama's point, I wonder if the stock resonator is 'fighting' with the unrestricted filter box. Could it be that the deckplate works but only in combination with the straight pipe? I know someone with the equipment to figure this out... !

Speaking of the 'improved' intake noise, I had a Z4 that had a port of the intake plumbed directly to the firewall to enhance engine sound. Without it, the engine was too far away and too quiet. The port had foam pieces in it that you could 'mod' (take out) to add variable levels of noise.

 

[tarmacblack]

Rob, how many runs did you make with the deck plate removed? If only one pass was made, I'm wondering if the ECU was trying to learn and make changes to compensate for the additional air. Perhaps it needed more time to learn?

I made a total of 6 runs in each configuration. There was almost no change to speak of in-between the runs. One thing to remember is the AFR curve is being affected adversely in Open Loop fueling (unless I'm off base and the UZJ100 is full time closed loop, doubtful). Open loop is generally handled by a fixed map. The map in most good models is a Volumetric Efficiency representation of the Engine. These values are generally not learned or trimmed, but stay fixed.

Just picking a little, but it's Transport Phenomena, not Thermal Dynamics. TP is what you would use to derive a flow equation from a Bernoulli base in order to predict the flow characteristics based on the surfaces interacting with the air. However, proper and accurate derivation of the equations for turbulent flow takes some serious computing power. In the end, it just wouldn't be worth it for a 5hp MAX increase from an airbox modification. Determining useful flow equations for laminar fluids over flat surfaces is a graduate-level course in Mechanical and Chemical engineering. Jumping to turbulant flow in a geometric box is some serious PhD reasearch study stuff...

In other words, trial and error tesing is MUCH more productive, MUCH quicker, and MUCH cheaper.

However, the tone really is nice. If you liked the open airbox, you should hear it with a straight piece of stainless in place of the OEM resonator intake.

Thanks again for your professional review of all this.

Well said Andy I agree, modeling is a lot of work and way out of my pay grade . The friend I spoke of is a masters level ME, working on his PHD. He does this sort of stuff for fun. I spoke with him last night and he shares the same opinion, the result isn't worth the effort Ironically this is coming from a guy who just re-routed the ABS pump and computer to the trunk of his car so he could try and squeeze another 10-15whp out of a stock turbo by using a long runner conical stepped manifold....

To bama's point, I wonder if the stock resonator is 'fighting' with the unrestricted filter box. Could it be that the deckplate works but only in combination with the straight pipe? I know someone with the equipment to figure this out... !

Speaking of the 'improved' intake noise, I had a Z4 that had a port of the intake plumbed directly to the firewall to enhance engine sound. Without it, the engine was too far away and too quiet. The port had foam pieces in it that you could 'mod' (take out) to add variable levels of noise.

I'll work on getting a pipe set up to replace the resonator tube.

 

[spencerorton]

Just picking a little, but it's Transport Phenomena, not Thermal Dynamics. TP is what you would use to derive a flow equation from a Bernoulli base in order to predict the flow characteristics based on the surfaces interacting with the air. However, proper and accurate derivation of the equations for turbulent flow takes some serious computing power. In the end, it just wouldn't be worth it for a 5hp MAX increase from an airbox modification. Determining useful flow equations for laminar fluids over flat surfaces is a graduate-level course in Mechanical and Chemical engineering. Jumping to turbulant flow in a geometric box is some serious PhD reasearch study stuff...

In other words, trial and error tesing is MUCH more productive, MUCH quicker, and MUCH cheaper.

However, the tone really is nice. If you liked the open airbox, you should hear it with a straight piece of stainless in place of the OEM resonator intake.

Thanks again for your professional review of all this.

I would also try to use a tuned air velocity stack to help bring the air in. Thanks for sharing.