Boost Flutter

[GNJeremy]

Ok, I've been testing and tuning here as of late, and after getting some things straigtened out with ATR, I finally got everything working alright.
I just have a few questions for you guys.
During a WOT run, I get some serious boost flutter in 4th gear. I can hear the air coming out of the air filter, and the boost goes from 19 to about 14 pounds during the flutter, and then goes away after about a second. Just wondering about what can cause this. It doesn't seem to do it under part throttle.

Also, I am getting some knock on my more aggressive chip settings. I run 116 octane, and no matter what I set the fuel pressure at, I get around 2-4 lbs of KR in 3rd and 4th gear. This is with the car running 20lbs of boost, at 24 or 26* of timing. I wouldn't think this would be too much, especially with the mods I have. It knocks if the fuel pressure is at 45psi, or 58psi and anywhere in between. I even drained the tank and refilled it completely with the c-16, just to make sure it wasn't the fuel.
Does this have anything to do in connection with the boost flutter? Any input would be appreciated.

 

[DonnieShort]

I'll take a stab at this

First, are you running through the mufflers and if so what are they? Stock? Atr? etc. How about the downpipe? Stock, THDP, MEDP? Second, does the knock go away after the shift? Need you to list more of your set up so we can get it fixed.




Donnie

 

[GNJeremy]

I'm running hooker muffs, and headers, and a poston's 2 piece downpipe, and no cat. The knock only happens on the more agressive settings, with more timing, and it's pretty consistent. always in third and fourth.. It doesn't knock on the shift into third, but it does into fourth. Am I running out of injector? I run 009's like I mention in my sig. I can't believe that they wouldn't be able to handle my combo. They are brand new.
The flutter happens in every setting, at the same rpm and speed everytime. Fourth gear round 90-100mph. The boost also seems to fluctuate a lot too. but only in the higher gears.

Here is a complete list of mods:
TA49
V4
009's
open K&N filter
new valve springs
shift kit
caspers fuel pump and hot wire kit (I suspect maybe the pump isn't keeping up?)
Other small mods, AFPR, Adj. wastegate, other stuff.
Ultra chip burned for the above combo.

 

[GNJeremy]

Still working on this one. Anyone know what causes WOT boost flutter?

 

[DonnieShort]

I'm not familiar with Caspers pump so I can't comment either way.

If your running pure 116, and that's with no 93 in at all, your car should handle the timing and boost no sweat. Just for $hits and giggles, do you have another chip to try? What ¼ times are you running ?



Donnie

 

[GNJeremy]

I haven't been to the track since my new mods, so I can't say. My old 8th time is in my sig.

I do have another chip, burned for a stock setup.

I was racing a friend tonite w. a 69 camaro, (see kill section) and since I had the boost turned down to 17psi, I didn't see over .7deg of KR. But I want to run 22+psi!!!!!! I know I can, just can't figure out why!

I had the fuel pressure set at 54lbs line off tonite for the record.