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Lazy low-end boost issue FBO s280

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Location
Montpelier, VT, USA
#1
I'm trying to get off the base map finally, so I sent my datalogs over to Adam at Tune+. According to him, the boost is really lazy from about 3000 to 4500rpm. I'm full bolt-ons s280 (mods list in signature), and he's tuned a ton of these, so I know he knows what he's talking about.

I live about 90 minutes from the closest actual dedicated tuning shop, so I drove it over there Tuesday. He ran his own datalogs and checked fittings and ended up replacing a vacuum line, but it didn't do much to solve the issue. He also checked the actuator, and it seems to operating normally. Next, he's going to try to pressure test the system to see if I have a slow leak somewhere in it.

Have any of you had this issue? What ended up being the culprit?

I'm hoping it isn't something with the turbo itself. I think next, if he can't find a boost leak, we'll try swapping back in the stock turbo and see if it will act properly at that RPM range, which might give us a clue as to what's going on.
 


JDG

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#2
Are you using the preinstalled Turbo Technics Wastegate Actuator with paint marks still intact?
 


OP
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Thread Starter #3
I live in an apartment and have nowhere to work, so I had everything done at a local shop. I have no idea about paint marks. I did order the Turbosmart 14psi wastegate actuator with the s280, but it wasn't pre-installed. If memory serves, it came separately, and then was installed at the same time the s280 went on.

The tuning shop says the first thing they checked was the actuator, and it appears to be operating normally.
 


Erick_V

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#4
Sounds like the wastegate doesn't have enough preload, hence the slow spool. How exactly did they "check" it? Did they just pressure test the system and confirm the arm moved at 14psi?
 


JDG

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#5
Sounds like the wastegate doesn't have enough preload, hence the slow spool. How exactly did they "check" it? Did they just pressure test the system and confirm the arm moved at 14psi?
This is exactly what I was getting at. Wastegate Actuator was likely not installed properly. I would ask them how much preload they installed it with, and if they don't know the answer (or the answer doesn't make sense), it points to a plausible issue that is easy to fix yourself.
 


OP
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Montpelier, VT, USA
Thread Starter #6
The tuner is overwhelmed with work right now, so I'm still waiting on a paragraph or two writeup of what all he's checked, but I definitely remember him saying the first thing he checked was the preload on the actuator.
 


Dpro

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#7
Sounds like the wastegate doesn't have enough preload, hence the slow spool. How exactly did they "check" it? Did they just pressure test the system and confirm the arm moved at 14psi?
I had the same issue. My original tuner who was the installer apparently did not set preload . I am still not sure how they managed to get 25lbs boost out of it. Though it was really funny because the car acted like it had hybrid less a S280 had a Mustang dyno sheet output that showed a huge bump in TQ in the bottom end that died down hard after 3-4k 252TQ and 215HP on the Mustang dyno:LOL:. It was fast but it was also a weird tune. started popping codes. I was like F this went to Adam at Tuneplus . He sent a basemap over and on his page per datalogging instructions he wrote make sure you are pulling at least 14lbs boost on the base map if not your preload needs adjusting. Sure enough on my AP I was saying a max of like 12lbs boost . So they had not set the preload right on the wastegate. So I had to go in and adjust it. If you go to my build thread I cover it with pics and description. The main you need is compressed air to connect up to the wastegate to push the rod out . I bought a little compressor for inflating tires from Harbor Freight:LOL: it worked great $36 dollars well spent and now I can air up my tires anywhere anytime!:ROFLMAO:
So ya after that I did datalogs and Adam commented it was a solid pre load . OP you need to check how much boost your getting on your AP if your below 14lbs its your pre load, also it could be your wastegate was installed wrong like JDG said.
 


OP
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Location
Montpelier, VT, USA
Thread Starter #8
Per my tuner: "boost is building much faster (you can actually get some positive boost in neutral when blipping the throttle) and hitting 20 psi at 2700 rpm. See invoice for work summary. It looks like the main issue was a sticking wastegate - There were positions where it had high resistance as I was fully opening and closing the wastegate by hand. The turbo wastegate arm was slightly bent, I do see that happen occasionally during shipping and it could have been easily over-looked by the installer. This was slightly pulling down on the wastegate actuator rod and that was in turn rubbing against the actuator bracket as well, which was compounding the issue. I basically lapped the wastegate by applying penetrating oil and continuously opening and closing the flap rapidly until the resistance decreased sufficiently, bent the arm up a bit and used a die grinder to clearance the bracket from the actuator rod so it would not rub."

Thanks for the tips, everyone. Much appreciated.
 


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