0Terry@BMS

*** EDIT *** Order link for the BMS drop in filter: http://burgertuning.com/corvette_c7_...ke_filter.html



Hey guys,

I've been slowly working on the Z06 intake system. What I've been able to confirm via flow testing is that the factory intake piping and MAF housing are themselves not restrictive at all. They could probably support 900whp. But the thick drop in filter base itself is where the problem is. It's molded such that it blocks off potential airflow in to the MAF housing.

To address this we designed a drop in filter that has a thinner and less restrictive base to better mate up to the factory MAF housing, kept the filter DRY to avoid oil contamination on the MAF, and using a flow bench optimized the pleats and other dimensions.

The net result was a drop in filter that offers 15% less restriction than factory and 10% less restriction than the "leading" aftermarket drop in filter, when flow tested through the factory intake piping. We actually went further and found a simple way to modify the airbox to accept a longer drop in filter that offered even less restriction, but after dyno testing, determined it was overkill.







With first articles of the new drop in and our trusty AFE intake in tow I headed to the dyno today for a few hours of testing.

The test car is a 2016 Z06 automatic that I've tuned with HP Tuners. I run it on 6 gallons of E85, rest of the tank 91 octane, and I've tuned it for a low 12s AFR and around 21 degrees peak total timing, with timing as low as 10 degrees in the midrange to reduce torque for traction purposes. Overall a conservative tune. The car has a 2.3" upper pulley, home ported throttle body, and 2017 supercharger lid.

Since output can vary day to day based on weather, fuel mixture, and other minor factors I did a few pulls with the AFE intake on to ensure I had a good baseline for the day. Worth noting for all runs I kept the starting manifold temperature the same with a similar cool down and found it easy to produce repeatable numbers.



Next, I switched over to the factory airbox and first tested the stock air filter. To keep everything apples to apples I had to go through the tuning and "undo" the various changes I had made to compensate for the AFE intake misreading the MAF. Primarily MAF sensor scaling, PE changes, and a minor adjustment to the base timing curve to keep timing and AFR similar. So often tuners fail to isolate variables which are what generally lead to wild and misleading test results.



Once everything was matched up I did a few runs and took the best of which to compare with the best AFE run. As expected with the AFE boost was marginally higher resulting in 10-15whp gained. Not the 30-50whp result people get when comparing a too-rich stock tune to a much leaner and over-timed intake only result (due to unintended MAF rescaling).

Next I switched over to the BMS drop in filter we're evaluating. I was expecting no additional tuning changes to be required vs the stock filter to arrive at the same low 12 AFR I run the car at. But to my surprise, the AFR was much leaner than I wanted with the stock MAF tuning. About 5 pulls later I realized I had to put back in almost every change I had made for the AFE intake. And after doing so, when matching up the AFR and timing curves, power with the BMS drop in was basically identical if not slightly better than the AFE intake.



I had set out to design a drop in filter that would give OEM AFR and timing values while allowing more flow. And what I ultimately discovered is that it's almost impossible to do so. If you improve the airflow MAF calibration differences are unavoidable. On the plus side, with this new drop filter, there is no longer a need for expensive and IMHO ugly intake systems. But we're going to have the same annoying problems that everyone has with the intakes now. Some cars might need tuning, others might throw an airflow CEL, etc. Little variables like whether your fuel is E0 or E10, elevation, DME version, will all play a role in that.

Anyway I've decided to move forward with the project and have a bunch of filters in production. When they arrive I'll start soliciting testers and get some 2016 and 2017 stock vehicles on the dyno to better quantify things for untuned vehicles. And for those tuned who don't like the look of their aftermarket intake... at least you'll have an OEM looking inexpensive alternative soon.

PS. I have a slightly used AFE intake system for sale.

TAK2TRK

Nice post. I'm interested. Currently running the halltech.

IM3CPO

Do you have a predictable model we could plug these variables into which would tell us the odds of needing a tune or not? Say I am at sea level, running E0, XX stock tune, etc., the model says "90% certainty a tune will be needed" or something similar? If one doesn't exist, any idea if it would be possible to make one?

Also- nice work on following the scientific method and being transparent with everything. Much appreciated and great post!

Larry M

Good info

Very interested to see what happens to a stock 2017 Z and stock tune 2017 Z with TB and XPipe

I've got a stock 17, I have no interest in tuning but I would like to get to a filter, TB, X Pipe

xkilo16x

Very interested as well. I have a 17Z and my green filter & x pipe come in this week. I'll be doing some Vbox pulls instead of dyno tests. I'm curious to see real world gains of these mods.

speedsquad

Terry, on the stock intake, are you leaving the small screen in front of the MAF sensor in place? I would assume the screen helps improve laminar flow across the MAF?

8850

I would be interest in seeing how this works on a 2017. I currently have the Green filter.

0Terry@BMS

Yes, airbox fully unmodified in the drop-in testing. The drop-in+ had the screen removed and airbox cage removed to allow a larger filter and further reduced restriction. But at this power level provided no power advantage. So we shelved it for now.

0Terry@BMS

Yes I'll definitely work on collecting more data there to better determine how well it does or doesn't work with 2016 and 2017 stock tuning. I wanted to do some stock map runs on mine while it was strapped but I had E30 in the tank. I'll run it out and continue 91 octane testing next week.

0Terry@BMS

Tuned or untuned?

Also for those with the "green" filter, do you have some photos of it side by side to the factory filter? Curious how their base is setup. Factory or optimized.

phantasms

Oh do I!

Count me in for beta testing. 2015 M7 Borla X, K pTB, Green

The Green base uses a much harder rubber but is able to be squeezed in due to no frame like stock filter. Once the base is inset it of course can't be squeezed any longer.

Unlike yours neither filter came all the way to the outer cage. A clear room for improvement.

0Terry@BMS

Got it.... The green filter is going to perform basically the same as stock. On the plus side, it definitely won't require any tuning.

Z0Sick6

It has shown gians at the strip by 01Defense who posted, and also showed 11whp on the dyno by another member. Phantasm also noticed like most aftermarket filters it does add a little extra boost. Would be curious to see how yours compares to it from a performance level.

snork

Interested in testing new air filters '17 Z06 M7 stock

C7/Z06 Man

Jason900rr

I'm interested! I'm looking for a intake right now but will hold off until I see your results!

sTz

Interested in the results as well

HorsePower Junkie

Terry,

How much are your replacement air filters?

Does it fit ALL C7 Models?? Including Base model Stingray, Z51, GS, and Z06??

Are they just a simple remove the stock one and replace it with your's that has the larger opening where it seals to the stock air box?

Will it run lean with your improved air filter?

Does it then need a tune, or will it recalibrate itself after driving it a while??

.

0Terry@BMS

I expect the filter will fit all C7 models including the Z06. Whether or not it runs lean without tuning or whether tuning will be required is to be determined. I can say with confidence that power output will match the popular aftermarket intake systems out there.

In order to discuss price, etc, I'd have to sign up as a vendor here and that isn't a commitment I want to make yet. But I can say under $100.

foreverfuelie