How to get boost lower?

[turbosam6]

I can't seem to get my boost down low enough to be comfortable on pump gas, probably because I run a high boost actuator. What can I do? I tried a grainger valve type setup, and I even tried disconnecting the wastegate, which, btw, got my boost down to about 0- talk about slow! Any ideas?

 

[squeeze87]

If you have the arm adjusted so it just slides over the arm, that is as low as you will be able to get the boost. bleeder or grainger valves are only for raising boost above the base level. I guess thats why heavy duty actuators arent recomended if you plan to run on pump gas.

 

[azgn]

you really can't get boost below about 18 with a hd actuator...the other thing you'll find is, if you do mash the pedal, a 45A will literally blow the wastegate open if set that loose and you'll dump all your boost...I can't keep the gate shut unless there enough pressure on the spring to run 21 lbs or so

best bet is stay out of it or run race gas all the time

 

[rob nolan]

With my TE45a and a HD Actuator i have mine set at 17psi. It took me a while to get it there but there is times it at about 18 after i adjusted it back from the track.

Hey Woody, i hope to have the tranny back here in the next couple of weeks. I got the Precision converter you told me to get. I got the 5 disk 0 pump 9 inch converter. Hope to run it soon.

Rob

 

[azgn]

Rob, you'll love that converter....just don't try and lock it up too soon (can you say bog.....) shoot for 5,000 + rpm in 3rd

 

[rob nolan]

Woody, thanks for the info on not locking it up to soon.

 

[mgmshar]

This may be a stupid question, but is the wastegate hole ported? The bigger the wastegate hole, the less boost you will make at a given actuator setting. I'm not sure if the 45a comes with a big wastegate hole or not.

Since I've installed my front-mount and ATR exhaust, I've noticed that I can't get my TA-49 to make less than about 17-18psi. I used to be able to get it down to less than 15psi, even with my HD actuator. This weekend, the wastegate is getting ported.

For what it's worth...

Mike

 

[azgn]

most HD actuators have a 18 lb spring....you can port all you want and won't do any good

porting not needed on '45's

 

[Brian Verson]

HEY ROB : LET ME KNOW WHEN YOU GO TO THE TRACK. I WANT TO GO. I FINALLY GO MY TO GO 12.56 @ 113MPH ON PUMP GAS ANS ALCOHOL.

 

[colby]

What if you shim the wastegate with a washer or two, just to put it more towards the exhaust housing, thus giving you a little more room to adjust the arm out some more.
This happened to me when I put the THDP on my car, I kept on hearing a jingling noise from under the hood. It turned out to be the flapper moving around because there was not enough pressure to keep it shut.

 

[NC87GN]

Take the boost down in the chip if your using a stock style setup with electronic solenoid. I had the same problem and modded the boost in the chip for 8# to bring it back to 14# with the HD wastegate actuator. Remember you want some tension in the rod to close the WG puck to the turbo or you will experience SERIOUS LAG. HTH..

Mike Banas
87GN

 

[squeeze87]

The lowest boost that can be acheived is the weight of the spring in the actuator. the solenoid only bleeds air/boost to raise the boost. If the puck arm is loose it will leak boost and be laggy but the weight of the spring still comes into play.

 

[mgmshar]

most HD actuators have a 18 lb spring....you can port all you want and won't do any good

I'm not sure I agree. If I open-up the wastegate hole, then the wastegate puck will open at a lower exhaust pressure, right? The wastegate puck will open when a certain FORCE is applied to it. FORCE equals PRESSURE X AREA. If I increase the AREA (by porting the wastegate), then the FORCE required to open the puck will occur at a lower PRESSURE. If the exhaust pressure is lower when the puck opens, then I would assume that the turbo will be spooling less.

Yes? No?

Mike

 

[squeeze87]

The wastegate arm will move as soon as the boost overcomes the tension of the spring in the actuator. If all things are equal, meaning just a hose from the turbo to the can on the actuator,(tuner style) boost = weight of spring.

 

[azgn]

what 'squeeze said...you first have to overcome the spring pressure.....porting will sometimes help after the puck opens to stabilize the boost (improves the flow)

I don't think porting will allow more exhaust to "push on the puck", but you'll find out soon enough that the '45 will overcome the spring if it is at very low tension

 

[rob nolan]

Originally posted by Brian Verson
HEY ROB : LET ME KNOW WHEN YOU GO TO THE TRACK. I WANT TO GO. I FINALLY GO MY TO GO 12.56 @ 113MPH ON PUMP GAS ANS ALCOHOL.

Brian, thats good on pump gas and the alcohol. I'm still waiting on the tranny to get done, so hopefully i'll get it back in a week or two. I'll let you know.

Rob