Issues with popular mods?
 

Been talking to Brian at Vermont Tuning as I was interested in getting his tune, however, after sending him my mod list he replied with the following:

The components that I have seen problems with are the injen (7300) intake, bnr recirculating valve and zzp throttle body. All three of these result in numerous performance issues that reduce the actual performance of the car and the magnitude of the offense is in the order I listed them.

In my experience I have seen numerous customers with the Injen intakes causing issues resulting in reduced performance compared to the stock intake - I can attempt to correct for the error in the mass airflow readings so it correlates better with the speed density airflow but it seems that the error is inconsistent due to turbulent airflow and harmonic (helmholtz resonance) effects that are due to design flaws. I would recommend tuning it on the stock intake and then you can compare the performance difference afterwards and decide if you want to continue using it. In terms of actual performance, the only restriction on the stock intake is the pipe between the turbo and the air filter housing and that pipe can be upgraded with an inexpensive silicone pipe from ZZP (~$130) or I can make a powder coated aluminum pipe if you want something that looks better and flows better than stock.

I can disable the 2261 DTC code that may trip for the bnr bypass valve you are using - in my experience the stock bypass valve is not a performance restriction of any kind and the modifications to the stock valve just cause it to operate incorrectly due to the added weight/mass on the piston, resulting in delayed opening of the valve between shifts which can cause surging and be harder on the turbo bearings (the ecm monitors the pressure before the throttle body and the mass airflow to determine if the valve is not opening fast enough (or stuck closed) and sets the p2261 code).

The stock throttle body is not a restriction, at least not at power levels up to ~ 435 hp based on measurements in actual mass airflow and the pressure drop across the throttle body that I have made. The larger throttle body just screws with the idle and throttle response making the throttle response more erratic on/off idle. You can certainly leave it on the car, but I have experience with many customer using it and many switch back to the stock throttle body and would not have purchased any of the above mods had they inquired with me prior to purchasing them.

Curious what everyone's thoughts are.

Solid comments in all honesty. Tuning around the recirculation valve takes alot of time.

i kind of prefer the stock intake for the air vanes. KN drop in seems pretty ok to me. I just cleaned mine with the conditioner kit. to the bnr which I have, so far, all reports have been positive for holding high range boost better than stock, but I guess it is possible there is a penalty during shifting transient.

I got one of those OG JacFab Valves it's a good product but it does create an issue with reading boost before it's there because of how fast it helps the system create boost without that built-in boost leak on the OEM plastic valve. I did however install mine the same time I did the FMIC with the longer piping but me and my tuner have seemingly gotten the small kinks worked out. I actually had a theory on why GM did this not sure how correct or head turning it may be but I theorized once that maybe the leak was intentional to help force out any condensation.

ahh yeah the air vents. I've had no issues with it, there was a light coating of oil on it last time I looked on mine. that part, if I were to say my least understanding of any of my mods its the bnr valve. Probably cause its been issue free, hasn't needed attention anyways. it just seems to work pretty good. I have looked at what is turbo surge, haven't found anything compelling in my logs to worry about it. short path with oem IC. It seems to be managing pressures as needed, but I will put on my list to take a closer look at sometime.

Just a follow up...I decided to contact ZZP to get their take on this and their response was that the recirc valve would be the only POTENTIAL issue they would run in to when tuning so it's looking like I might just have to bite the bullet here and drive the 40 minutes to my nearest dyno shop and get it done...any advice here as I'm very new to tuning if you couldn't already tell?

Have your dyno tuner look at what your actual and percieved psi is. When I added the Valve it was reading the psi as there when it wasn't fully and closing the TB blade early. Again I added the longer FMIC pipes at the same time and have since tuned the issue out with my tuner after some troubleshooting.

Well? if your doing the tune, you will be Very happy with all the supporting cast of FBO you have. ZZP, trifeca or vermont can also support you with remote tune programs they offer. There are 2 schools about road vs dyno and either way is fine. I do my own road tuning and logging and I feel in MHO that road reflects more accurately for real world driving for M6. I used ZZP Matt before and can vouch the base tune will be solid. Then you can get a dyno pull for proofing, and the more 'better' way to report earnings is to report 1/4 run times. If you go to a shop please post up the before and after charts.

I didn't see EBs post up there before, but an inersting thing about the psi, I now have a physical boost gauge in the snow controller and I have seen it report higher psi (27) on the hot side pipe than is measured in hp tuners logs myself. It could be due to real pressure difference inside the actual manifold where the MAP is though. Don't know if it means anything for even if it matters, but there it is. Boost draw down isn't as big a factor, at least to me, on M6 because of manual clutch and I only notice it once in a while with spirited driving and abrupt stops. Like only when going faster than I should on city streets. There's no BOV on this engine. If I drive like a normal person its then its feeling fine....

Another update: Completely forgot that BNR offers a tune so I contacted them w/ mod list and they responded that they would have no issues tuning with my mods so I ordered their tune today. Will make a new post reviewing their tune once I receive it and get it dialed in.

The owner of Trifecta dyno tuned my car with FBO's including their upgraded turbo from Mach5 with the JacFab/BNR recirculation valve installed on it. He was amazed at how well the aftermarket valve worked. We were getting peak boost at 30psi and holding steady at 26.5psi.

I've been looking at the boost draw down after hard pulls in my logs. I can see that the throttle response does indeed have some activity after I let off the gas to zero. the TP shuts to about 20 degrees (not idle) as boost is maintained at high level for fractions of a second so it boxes the boost in the piping. With the Accelerator Position PID at zero, the Recirc valve opens (i.e. BNR Valve) then the TP (commanded throttle position) opens another 4 degrees, and that is to relieve the inlet pressure as boost pressure starts to subside. this all happens in fractions of a second. RPMs continue to climb for about less than half a second, as much as 90 RPM, after you let off he gas. Idle is about 17.3 degrees. Sometimes there is a more exaggerated effect depending on how the engine is building boost when I let off the gas. Its all anti surging strategy. I wonder, I just wonder if an aux recirc valve would work....and how that would work to do away with the ltg 'throttle surge'.

Just bought my intake tube :)

Yeah, I don't know about all of this at all reading through it.. Pretty much every negative "side effect" listed here, is either Already there in the stock tune, or is totally manageable using one of the many tables available in the tune. Hell, there are adjustments in the tune for the valve itself, throttle pressure across the blade, even turbo surge.. Now the Injen intake.. I gotta agree on that.. Don't like it.

I didn't have my car long enough before I started messing with it so I don't even remember stock. I seem to remember some of the "anti-surge" or what ever you would call it with the racechip. But its not even as bad now with the current setup. I got TP pr dialed in pretty good. I would be curious of the table that talks to the valve though. Seems to be Neg Pressure Drop and Surge Limit tables. I keep M6 in mind for dumping pressure during shifts so it hasn't been an attention getter for me anyways, but maybe a good segue some time to look at.