Gen2 air filter dyno

[jumjum01]

Does anyone have any dyno sheet that displays difference i performance from only changing the air filter in the gen2 airbox?
I loose 4 hp in the top rpm when switching for gen1(bmc air filter) airbox to gen2 (stock filter) airbox. So either the air filter makes it loose HP or the gen2 airbox it self. I have put gen2 throttlebody on my gen1 and only gen2 airbox will fit now. I dont like loosing out on 4 hp.

 

[sixpack577]

Probably both.
A bmc filter in the gen2 box should gain a couple hp, but I don't know about 4.

 

[Bumblebee]

Tuning is the key...getting the AFR where it should be is a definite requirement..

Judging by the knowledge you have of it losing 4 hp it has spent time on a dyno...get the AFR set up and there is a good chance you will find that hp and more.

 

[jumjum01]

Tuning is the key...getting the AFR where it should be is a definite requirement..

Judging by the knowledge you have of it losing 4 hp it has spent time on a dyno...get the AFR set up and there is a good chance you will find that hp and more.

AFR should be closed to perfect at WOT. This is a print from the log on the dyno run with "ramair dynomode" enabled in the ECU.

 

[busagreek]

What velocity stacks on gen 1 box and what on gen2?

 

[jumjum01]

What velocity stacks on gen 1 box and what on gen2?

Gen 1 airbox 2 long and 2 short stacks. Gen2 airbox 4 short stacks in first dyno run and 4 stock gen2 semi-long stacks in second run. no real difference

 

[jumjum01]

Does anyone know where you can buy "uni prefoam". Johnnycheese says its the best air filter material. Cant find it antwhere, not even google knows what this stuff is...

 

[sixpack577]

Email Uni

www.unifilter.com

 

[Bigboy Busa2]

Does anyone know where you can buy "uni prefoam". Johnnycheese says its the best air filter material. Cant find it antwhere, not even google knows what this stuff is...

Where is johnnycheese and when did he say that?

 

[jumjum01]

Where is johnnycheese and when did he say that?

He has mentioned it a couple of times in some older threads (seach uni prefoam).
Dont know about his whereabouts

 

[jumjum01]

Today I did some experiments with my gen1 /gen2 airboxes to figure out why the busa keeps losing power whenever using gen2 airbox. I made a flow / vacuum bench tester using 2 vacuum cleaners connected to airbox stacks to generate flow in the same direction as the engine would. I then hooked up my vacuum meter (I normaly use for TB synchronization) after the air filter. My theory is that the restriction generated by the filter will generate a vacuum in the "filtered air" section of the airbox.
Here are the results. 1 mmH20 equals to 0.098 mBar.

Gen1 airbox w/big airbox mod:
-No filter: 6 mm H2O
-OEM filter: 23 mm H2O
-BMC filter: 13 mm H2O

Gen2 airbox:
-No filter: 11 mm H2O
-OEM filter: 28 mm H2O
-G3 filter: 25 mm H2O

Gen1 airbox stock w/flapper
-No filter: 35 mm H2O
-OEM filter: 44 mm H2O
-BMC filter: 36 mm H2O

I have no idea how the vacuum cleaners flow compares to the actual air flow generated by the bike, but this at least gives some comparison between the restriction of the filter and airbox.
The experiment results supports the dyno results, gen1 airbox with BMC air filter flows better that gen2 with OEM filter...
and by the way gen1 airfilters have 60% bigger filtration area because of the oval design.
I have not yet invested in filters for the gen2 airbox, because the performance filters are more expensive and I dont know which brand to choose.

 

[sixpack577]

I think the gen2 airbox will flow as well as the gen1 with a BMC filter in it also, because it has less filtering material in it to the slow the air down than a stock filter does.

 

[busagreek]

You have gen2 throtlebodies on gen 1 head?
What ECU?
What about secondaries?

 

[jumjum01]

You have gen2 throtlebodies on gen 1 head?
What ECU?
What about secondaries?

Yes gen2 TBs on gen1 head, STV removed.
Gen2 ECU, harness, sensors ect.

 

[busagreek]

Yes gen2 TBs on gen1 head, STV removed.
Gen2 ECU, harness, sensors ect.

Put on the secondaries and take your hp back....

 

[jumjum01]

Put on the secondaries and take your hp back....

After testing airbox / filters i am convinced that the airbox and filter was the reason for hp loss. Best HP numbers where made with gen1 TBs and gen1 airbox w/BMC filter.
I have modded the gen1 airbox to fit gen2 TBs now. I will probably do a dyno run with secondary flies installed and one without. Pages and pages of discussions on the secondarys but no hard dyno proof...