gmtech16450yz

http://www.hptuners.com/forum/showth...nt-to-see-this

Speedforhire

Thanks for the insight.

grocerygetter

interesting. I know the combo of a max effort ported throttle body plus where ECS moves the MAF to on the blower kit makes for a weird MAF signal at idle on my car as well. Once you crack the throttle though it works as it should.

Speedforhire

...........idle characteristics are finicky.

tblu92

This is nothing new to the tuning community----Any time "you change the original location or inlet pipe diameter" of your MAF---The MAF table needs to be re-scaled-- C5--C6 or C7----
In extreme cases at idle it can never be corrected perfectly back to stock--But there are other ways via tuning other than the MAF table to correct Idle Airflow or low RPM Airflow------This is nothing an experienced tuner worries about-- Idle-- hunting--- surging--- dying are some of the easiest things a tuner does----

gsflyer2011

3 years ago when I replaced the stock Donaldson with K&N filter, I very quickly noticed the surging, the change in the performance (detrimentally) changed it back and forth few times, even left it in for a week to see if the new PCM would adapt to the new values, nothing had worked. I hated it and subsquently sold it for half the price. When I reported this here on the CF, I was ridiculed, by many. This makes lot of sense and explains why.

gmtech16450yz

Right on! Your assessment back then was dead on, it's too bad you were ridiculed for trying to educate your fellow forum members. I've had my share of naysayers too, believe me. I hate to say but you would have had WAAAAYYYY better luck and less chance of being ridiculed on another forum.

tblu92, speedforhire and grocerygetter,

Obviously none of you guys are tuners, or grasp what I'm trying to show you. That doesn't mean it's not true or valid. This isn't about MAF scaling, idle or any of the things you guys have said "are not new to the tuning community". What I'm saying obviously IS new to you because you don't understand it.

ls1121

I cut a hole in my radiator shroud and dropped in my LS7 intake. Many said it cannot be done and there would be surging and I would need a Tune to get rids of the surging. I stayed with the stock LS9 Donaldson Air Filter and have never had any surging, just lots of cold air.

interesting read though.

Boomer111

I experienced surging with the Vararam. Eventually got rid of it for this and other issues.

The slight surge at a consistent rpm would not tune out either.

It was a slight surge not easily felt by the passenger nevertheless it was annoying for me.

Interesting link, thanks.

gmtech16450yz

Hi guys, haven't been on here in a looooong time.

I thought I'd resurrect this thread because I just happened to run across this problem again. "Somebody" I know just bought a C6 ZR1. It has an Attack Blue filter in the stock housing. This new owner immediately noticed the surging. I went for a ride and drive and I could also totally feel the surge caused by the aftermarket filter. I did a few logs and sure enough, you can see the MAF turbulence. It also didn't help that whoever tuned it had the MAF transfer set to 0 rpm. Yikes. A stock Donaldson filter is going back into that ZR1 ASAP. (As are the stock exhaust manifolds so that LS9 can get it's lost low and midrange power back that the giant long tubes killed. lol.)

So again, don't waste your money on anything but the stock Donaldson air filter in these cars. GM did it right on that particular item. Keep it that way and your engine will run smoother.