TrendSetter

the idle timing is all over the place, it jumps from about 2.5 to 18, but ill admit, i reduced it to try to get the cool idle sound. the car idles ok, its more the 1000-2000 rpm area that it has trouble and i think you hit it with the transient stuff.
I bought this car already done and tuned and its my first e38 so i havent had a lot of experience yet. ive only tweaked a few things buit I think the right answer for me is to grab a few of your videos and just start playing with things when i have time.
Really appreciate the info, Greg, ill be reading that post probably 10 more times in the next few days.

SLOW SEDAN

iTrader: (13)

This goes back to low power, I had the same kit on my C6 with pretty much the exact same GT3076 upgrade and upgraded single port actuators. MAF was pegged on anything more then 13-14 PSI I think it was and switching to an SD tune was free and easy instead of rigging up a larger pipe or scaling, etc... Ended up running the kit up to 20+ lbs then selling it because it kept falling off up top, I even tried larger AR turbine housings, just wasn't enough turbo for me. I deal with MAF's all the time on other peoples cars and upgrade tube size for guys that want to keep the maf 4" , 4.5" etc. However on big power setups they don't run air filters so those aren't a restriction either. I haven't seem a MAF setup that will easily handle 20-40+ PSI from a 200+ lb/min turbo (or two of them).


Again back to low power setups which is where single port wastegates are normally used on small T25/T3 internal gate turbos. Most everyone else with T4 or T6 turbos uses external gates with dual ports, with most big power setups are using 66mm gates with electronic controllers except where limited by class rules.

ddnspider

iTrader: (26)

Have you tried messing with real time control (DVT for Efi Live)? Should let you dial in idle timing pretty quick and can monitor map for best vacuum.

TrendSetter

I have not, but thats a good idea. I am going after some weird goals which is part of my self inflicted problem. i want the car to idle really loud and rough and all that coolness but get good fuel economy and drivability. i think its possible its just something i need to work through and i simply havent put enough time into it yet.
this maf/sd stuff sounds like its worth a try though.

ddnspider

iTrader: (26)

@turbolx "I just want to make smokier tires" Sounds like what I'm trying to accomplish.

SLOW SEDAN

iTrader: (13)

This is where a mix of Alpha-N and Speed Density is fun.

TrendSetter

Greg is a funny guy. one of the episodes from a few years ago you can hear the ice in his bourbon bouncing around the whole time hes talking. I think we would get along in real life.

ddnspider

iTrader: (26)

He and joecar are the 2 key people who helped me understand how to tune Gen 3 stuff.....and realize how many tuners out there are really tooners

turbolx

I think you're forgetting the basics of turbocharger operation. The wastegate actuator is controlled by DELIVERED pressure, which would theoretically be the same at both sea level and altitude. The biggest difference is that more compressor shaft speed is required to generate that final delivered pressure/flow when starting with a lower barometric pressure. Moving from altitude down will actually make things easier on the turbo.

What you really want is VVT. In the meantime, stick with the fundamentals like we show in the videos. Getting those right in the order in which we present them will go a long way toward eliminating other issues. Thanks!

If you were using the LS2 based kit intended for the Delphi MAF housing, I am not the least bit surprised. I fabricated my MAF housing with a section of 3.5" stainless and a MAF saddle for the LS3 element, which has far less restriction. As an added bonus, the LS3 element is also less sensitive to reversion, yielded a far more accurate reading at idle.
To be fair, the APS kit was never intended to make four-digit power. It's a kit designed for street cars, with incredible durability at a reasonable power level.
"Low Power" is relative, I guess. To be fair, anyone making 2000hp in a class specific racecar has to acknowledge some compromises versus something that is more of a street car. The context of this dicsussion was for street driven vehicles where drive quality, idle quality, fuel control, and good manners (as often judged by the passenger's tolerance for disturbances in the car you insisted upon driving on date night) are sometimes more important than the final power number. Don't even get me started on emissions and fuel economy calibration.

SLOW SEDAN

iTrader: (13)

I'm well aware I can make it work if I want to, I used an LS3 MAF on a 4" pipe for an F1 procharger setup on 20+PSI that worked fine, as well as many others. I just personally prefer a VE table, one less sensor to look at, quick and easy to adjust, translates well to others that use standalone, since most people head towards standalone as they make more and more power they may as well get familiar with it. You don't see many stock ECU's over 1200hp, if nothing else the safeties and centralized logging afforded by the upgrade are priceless. Emissions is a null factor in my builds, but fuel economy is actually great for the setup, easily get 20+MPG cruising on E85. If a client wants to retain the MAF then I'll do what they wish, but on my personal cars, race cars, etc, the MAF hits the parts pile and my bride never even noticed

aaronc7

Apologies if I glossed over my setup. It's a C5Z Corvette with a centrifugal blower. I think it will flow around 15 percent more air at sea level. A rough hack like looking at the LS3 MAF curve makes it like I may be OK, maybe hitting around 86lb/min actual around 11500hz.

I was also looking at the data supplied with the Lingenfelter 100mm MAF housing which showed it hitting around 70 lb)min at 10500 hz in a 4" housing which led me to believe I wouldn't make it on the 3.5 too. edit: I see now that LPE MAF doesn't even use the same style MAF, so that isn't relevant at all. So it's looking like I should be good to go with a 3.5" diameter pipe and may actually be the perfect size for my application.

aaronc7

Well, I'll just close the loop on this.

Tried it out, first issue was that even after getting fuel dialed in, the SD tune just drove a lot smoother. Quite possible if I had kept at it, I could have improved it, but thinking back, I don't think my car drove as smooth as it does now, back when I was NA and still had a MAF etc. Maybe due to the cam, idk.

Other issue was I hit 12000hz at around 6300 rpm on a 6500 rpm car. So that was actually alright, but I live at 4300', so the moment I go back down to sea level I would be getting into trouble.

Combo of those 2 things I just went back to SD and will be staying here. Was a fun experiment for me nonetheless.

This MAF housing I got beautiful and amazing quality, but looks like I'll be selling it. My MAF signal is way smoother on this thing than it ever was on the stock C5Z MAF pretty sure too, I guess the straightener works. These guys make the housings if any size if you guys are interested.

ddnspider

iTrader: (26)

Nice to see you were able to try it and experiment. I'm doing that with turbos right now. Fun to try stuff out and see the impact.

Darth_V8r

iTrader: (4)

A-A-Ron, that's a really nice looking MAF!! It's a shame it didn't work out, but was a valiant effort.

aaronc7

You turbo guys who are doing this, are you running the MAF pre turbo or in the charge piping (blow-thru)? I wonder if that has an impact on overall performance as well.

Yeah, the MAF housing turned out to be amazing. Thought about keeping it, but I ended up just cutting up my stock pipe and going back to the regular "GM IAT". About $150 total for housing, sensor and harness/connector.

I'm going to be selling it if anyone is interested.

ddnspider

iTrader: (26)

I always have it in a blow through config.

SLOW SEDAN

iTrader: (13)

Ya pretty much every setup I've done or seen is the same if they keep the MAF.

In my instance I don't have any pre turbo piping, and only a very short section of 90 degree 3" pipe from turbo outlet to throttle body that also has a BOV on it,so pretty much worst case scenario for a MAF setup.

Glad you got the SD sorted out!