Installed new TA-49, couple "problems"

[tminer]

I also installed a power plate and ATR 7th injector hardware (replaces the vacuum block on throttle body) at the same time.

At 15 psi and part throttle I can hear a fluttering similar to turbo farts. Boost seems steady and giving more throttle eliminates the noise. I do have a CAI so I hear a lot of intake noise anyway. As I wrote this, I recall that I was going to change my SMC trigger point to see if that made a difference, but never did try it. Any ideas? Should I even be concerned?

The other problem is that I can't seem to get more than 22 psi. I have a BstC and 2 solenoids. My base boost is about 16-17 psi. I also have some switches so I can run 1 or 2 solenoids off of either the cpu or the BstC. Doesn't matter what combo I use, max is 22 psi. I get about 19-20 just on the chip and 1 solenoid and it only takes about 1/3 turn on the BstC running the other solenoid to get 22 psi. I am all but 100% certain that the problem isn't in boost control. Whatever boost I set, it does stay stable.

TB to pan is stock except for ATR 7th and power plate. CAS V4, THDP w/3" cat, Hooker cat back, 3" CAI, SMC and the basics.

My first suspicion is an intake (aka boost) leak, except everything seems normal right up to 22 psi. I'd be interested in any techniques for finding a leak (I don't hear anything and only used the supplied gaskets when installing the pp and atr).

The TA-49 has the standard size wg hole. I would assume that if wg was being forced open that the boost would fluctuate. I did pop off the THDP and double checked puck alignment. Didn't have any carbon build up yet, but eyeballing it seems centered and puck is much larger than the hole.

Thanks,
Tom

 

[GNVAIR]

How tight is your wastegate rod? If you shortened it significantly it will surge/flutter at part throttle. My TA49 does this as do most larger turbos. My does it more the shorter the rod is.

 

[tminer]

It is not very tight at all. I have had that problem before when trying to run 22+ psi with one solenoid, but the boost fluctuated several psi when it happened. In this current case the first thing I did was check the boost gauge while it was happening and it was steady at 15 psi. But it sure does sound like something is going on in the compressor. I am going to try loosening and even tightening the rod to see what happens with both problems. Hopefully it won't rain tomorrow evening.

Tom

 

[UNGN]

Originally posted by tminer
At 15 psi and part throttle I can hear a fluttering similar to turbo farts. Boost seems steady and giving more throttle eliminates the noise. I do have a CAI so I hear a lot of intake noise anyway. As I wrote this, I recall that I was going to change my SMC trigger point to see if that made a difference, but never did try it. Any ideas? Should I even be concerned?

That's compressor surge and throttle body flutter. Part throttle with 5-15 psi of boost is right where this happens. The throttle blade is not designed to be partially closed while the turbo is making boost and the compressor is not designed to pump air against a closed throttle blade. Yours sounds pretty mild. With a boost controller, you can regulate the boost with the wastegate as the turbo gods intented. Us guys that set our boost to 23 psi to race, then drive home from the track, regulating our boost with the throttle foot can get surges bad enough to shake us out of the car.

 

[tminer]

Ahah! I do have my BstC triggering at a very low tps voltage. I'll play with that if it ever stops raining!

Thanks!

Now, why can't I get more that 22psi? Cat? Leak? Stock heads? I got more out of the stocker, but it probably took less exhaust flow to achieve it.

Tom

 

[tminer]

All is well now. I set the BstC trigger to 4+ volts and that significantly reduced the flutter. I am still getting some small occurrances, but I think I can live with it. I do kinda miss 15 psi at part throttle.

Turns out I needed to tighten my wastgate rod some. The puck must not have been sealing real well. I only increased the base setting 2 psi, but the BstC will command 25 psi at 3/4 turn now.

And I can run 25 psi on Sunoco 94 and 100% denatured Gotta get the ATR 7th running so I can get my O2s up and thin out the alky. Heck, I can run 18-19 psi without alky but its pretty lean. I'd say the power plate is worth every penny.

Tom