I'll try to post them up this week. I am in the middle of a move so it's a little hectic right now.

If I recall correctly, it showed about .3-.4 leaner, and still under 10.5 AFR with the standard "working" filter.

The "bad" filter lost boost and ran richer, into the 9's.

 

razorlab ... did you guys reset the ECUs between each part swap during your test?

 

From the testing I have done the new hotwire MAF in the Evo X is *very* sensitive to airflow changes. In theory I am thinking the "velocity stack" filter creates extra turbulance the MAF does not like. I haven't posted boost/afr charts yet but the "velocity stack" filter made the car run less boost and much richer AFR.

For the 45 degree silicone pipe we kept the MAF at the stock location. I wanted to see if this would work for packaging purposes of the heat shielding. Obviously it did not with either filter. The maf is larger than 3" on the turbo intake side and we did not have a reducer silicon unit at the time. We are planning to do more testing with this 45 degree coupler however as we really want to move the filter as far away from the motor as possible.

We will post photos once we get the final shippable product done. As far as pricing we will be trying to make this as cost effective as possible.

Paul is a good guy, say hi to him for me.

We did a round of testing without resetting the Ecu and a round of testing with resetting the ECU. I spent about 4 hrs on the dyno doing all this testing. Resetting the ECU did not show differences. Also keep in mind this is a "factory reflashed" Evo X. The ones that haven't been flashed yet might show something different.

Once we get as close as possible to the final product we will be testing it on at least three Evo X's.

 

Does this info share any similarities with the 8s and 9s? Will velocity stacks affect them the same way as well?

 

thanks for the response. anticipating more info on your product for sure!

 

From what I have seen over the years and tuning many 8/9's, no.

The biggest thing that messed with the Karmen Vortex MAF on the 8/9's where some of the adapter plates used for open filters. The filters that bolted straight to the MAF messed with the MAF the least.

 

I think everyone calling an air filter with the inverted cone filtration element in the end a "velocity stack" is just going to cause confusion in the long run. Alot of newbies are reading this post and spouting off how "velocity stacks" are suddenly bad.

An inverted cone filter is not a velocity stack. It's an inverted cone filter.

A "velocity stack" originally was a tuned length tube with a radius on the inlet end to smooth flow into the "stack". The tuned length "stack" produced a Helmholtz resonance at the desired engine speed based on Nth order calculation of air column oscillation frequency. The "velocity" portion of the term came from the radiused inlet to smooth airflow.

Now days a "velocity stack" is no longer a tuned length runner, it's just a tube with a radiused inlet. This is still significantly different than an inverted cone air filter.

 

Yes indeed. That is why I put it in quotes. I've seen it called that alot on here so I felt that was the best way to describe it so everyone could possibly understand.

Now that I am thinking about it, I do agree with you that it can be confusing for people that know what it actually is.

When I get some time I will go back and edit it to a filter with a inverted inlet on top.

 

^Yeah that was a bit misleading when he first called it a Velocity Stack. I was trying to picture that lol. I think we all know what he meant though after he explained it...and apparently this design is not working for him on an X. To be on the safe side for now I'm staying away from these inverted cone types. This is good info on why you can't just throw any old aftermarket intake on this style of MAF and expect miracle power.

That whole speil' on Helmholtz resonance and velocity stacks radius was quite enlightening though lol


I'll be calling the boys at GST early monday am

 

Cool. I want you all to understand I was not trying to be critical, just an observation. An ounce of prevention is worth a pound of cure kind of thing.

I can see how the inverted cone would cause some problems with the MAF also. The rule of thumb for these types of systems is that there should be enough length of tube as a straight shot before the MAF. That rule of thumb length is 3.0 to 3.5 times the diameter. So if one was running a 3" ID tube in front of the MAF, then it would be best to have 9" of straight tube length directly in front of the MAF. Maybe this is not practical given the space constraints under the hood.

The straight length of tube solved alot of problems a long time ago in the Mustang world, prior to sophisticated tuning tools becoming available. This was back when everyone was tuning with FMUs and aftermarket timing retards and secondary injector systems and modifying base fuel pressure, etc. Basically the "dark ages".

 

So is this intake good or bad? https://secure.buschurracing.com/cat...c9daf929c753a6

Sorry but I don't know much about cone filters.

 

Its fine.

+1 for the OP. Great info.

 

so without the factory reflash and your filter kit you got 22 whp and 22 wtq right?

and with the reflash and your filter kit you got 26 whp and 13 wtq?


so the question is.... is 4 more whp worth more then 9 wtq?

 

Just get a tune with ECUTek or the ecuflash when it comes out... 4whp or 8wtq is nothing compared to the gains you will get with either and a good tuner.

 

any pics of the filters tested? what is a velocity stacked filter? thanks!