Tony

Just for your info, I initially removed my MAF screen when I installed the Donaldson with the cold air cover. Thinking this was part of the problem, I replaced the stock unit with a GMS MAF. This did not help. I contacted GMS and they offered and sent a replacement unit with a 5% richer setup. This didn't help either. Unfortuately, throttle response is awesome with the shroud open and the cold air cover, but it sucks on deceleration or coasting.

 

I don't think your problem is with the Blackwing. I've had zero problems on my 2002 MN6 Coupe with it. Hope you get your problem fixed.

 

Steve. Thanks for the explanation. Do you see the tach go up and down too, how many RPMs? Or if it just the 'feeling' in the car.

 

Interesting.....
I quess I can try adjusting my MAFT really rich just to see if the surging goes away. I thought I may have an issue with my Pro-Auto Tech MAF, but you tried a stock one and an aftermarket one and still the same results. I only have surging when when I'm not on the gas so maybe the influx of air with no fuel causing a lean condition......Back to the autotap........

Tony

 

Do you also have the cold air (open shroud) or just the Blackwing? I have been watching this and several other threads and it seems many with the 02 cars are experiencing problems when going to a better flowing system. I was considering the Blackwing, but now am unsure.

 

I'm not using the cover or open shroud install. I'm just using the filter with cold air screens in my fog light area. No one ever provided hard proof (even when they said they would) of a problem with the Donaldson and 2002 Vettes, so until I see this proof published, I consider it propaganda for the competition. If anything, the issue was with a single 2002 Z06 and not 2002 Coupe/Convertibles.

There are several of us on the Forum with 2002 Vettes with Donaldson Blackwings, and we haven't seen any problems.

As mentioned in a post above, the surge problem was supposedly related to the non-Donaldson-designed/manufactured Blackwing cold air cover.

 

Maybe I am not following this properly, but it seems that anyone that introduce cold air to the new cars are having the problem. The Vortex seems to also have the problem from what it appears in the previous posts. I was thinking of just using the Donaldson, without the cold air cutout.

 

Hmm... I haven't heard that.

 

I had a donaldson without the cold air cover and no surging, but with the cover it surges. I have a 99 vette.....

 

I have an '01 A4 with blackwing and Z06 air screens with 1' holes cut for better flow on the fog lamp assembly. I have also removed the screen from my MAf and have never experienced the surging effect you guys have. It does sound worrisome though. Good luck with your investigation and if someone pinpoints it please tell the forum. Sounds like it could happen to anyone at any time for no psrticular reason at this point.

 

I believe that as long as you don't cut the shroud under the filter then you will have no surging issues. Leaving the donaldson as is without the cold air lid seems to work ok. I do know that team-zr1(John R) built his own cover for the donaldson and has no surging problems, but he is a master at tuning these cars. Maybe the design of the cold air lid is crap. We all know it doesn't seal well. The one thing that I am sure of is that with the cold air lid my air intake temp could be as much as 35 degrees less then a car without the lid. I compared my car with a car with a vortex and the air intake temp was the same. I do drag race the car so every little bit of cold air helps. I'll figure this surging crap out sooner or later.

Tony

 

Hi all,
Hey Tony, I do have the stock MAF setup on my car, except that I took off the MAF screen a long time ago. I never had a problem with the car's performance until I had the cold air coming in. I still have my shroud cut with the stock air box setup now(minus the cover) and have NO PROBLEMS at all.
Steve ('97 C5)
MMarquez,
I did also develop a tach rev/drop condition, but after weeks of having the new setup and surging. That was the last straw that made me switch back, even though it was great to have such power!


[Modified by Blackjetvette97, 1:18 AM 1/13/2002]

 

The cold air intake with either the Donaldson or Vortex caused light surging and idle recovery problems with my 2001. AutoTap confirmed the car was running lean.

I don't believe turbulence has anything to do with it. My MAF screen is intact.

From what I have read, the MAF translator should do the trick, but I don't think it has a wiring harness for the '01 or '02 yet.

 

Upon installing the Blackwing; cold air shroud; silicone hose couplers; and larger air bridge I too had surging on my '02 Coupe A4. The MAF was left stock and the screen was not removed. The surge only occurred at light throttle and no load conditions in 3/4th gears. The recurring circumstance for me was cresting a hill and driving down its backside. Most noticeable at 1500-1800 rpm. The guys at Xtreme Motorsports autotapped the car. The results showed no problems with A/F ratios. It did show convertor slippage. I discussed the matter with the local dealer service tech that does the work for the Scottsdale club and who owns a C5 himself. He advises me it is not likely a convertor problem. He has seen this circumstance before and says it is the convertor trying to go in and out of lockup at that point. He said it does not happen on all similarl cars, but randomly. He suggested I lightly tap the brakes when the circumstance occurs. I have tried that and it does stop the surging. For what its worth, while I was struggling with the reason for the surging, I also had a DIC code of MAF failure and the guys at Extreme replaced it with a new one. It still surged. The DIC code came on 3 consecutive times--at the 125, 130 and 140mph speed points.Comments anyone?

 

Hi GJPUNDSACK,
It's interesting you mentioned the RPM range your surging happened in because I noticed this exact same range on my problem. I have never noticed if tapping the brakes stopped the surging, but I know that when I had ghost revving, it stopped it immediately. hmmmm

Steve

 

There is no problem with the Donaldson Blackwing hooked up to any C5, in fact it works great. The surging occurs (most definately on an '01) when and only if you open up the radiator shroud to allow more air flow, regardless if you use the cold air cover or not. Only then is surging present during coasting or deceleration.

 

Well, not quite.

With the cold air cover installed, I experienced much of what has been described here.

While experimenting, I took the car for a drive with the radiator shroud hole open and with the cold air cover removed. The difference was dramatic. As in, the car would barely run below 3,000rpm if my forward velocity was around 10mph or more. I had to heel & toe just to brake and keep the engine running at the same time. The surging was significant in that particular configuration.

The fix was to close the hole in the radiator shroud. The effect (no surging) was immediate.

 

I just put my Vortex on a few weeks ago and have no problems at all. The car runs as smooth as it ever has. It could be something wrong with the MAF, which is where I would start looking.

 

Not quite? I may be missing something here but I think you're saying the same thing that I am. It's the open shroud that causes the surge condition on an '01, not the Donaldson. Whether or not a cold air cover is afixed or not, the surge will still be present if the hole is open. Only when you close the hole in the shroud does the surge go away. I am curious, however, as to why some owners with the Vortex and open shroud are not experiencing the surge on an '01.

 

Life,
Maybe. I was commenting on this sentence, "The surging occurs (most definately on an '01) when and only if you open up the radiator shroud to allow more air flow, regardless if you use the cold air cover or not."

Just wanted to make others aware that opening the shroud, but not using the cold air cover, caused significant problems.