When an Internal is used externally...

[Ottoman]

I have a T3/T4 with an 38mm Internal wastegate.. and adjustable arm on the actuator

I am using an external Dump Tube with it...


the car drives and boosts ok.. 0.77bar according to my AVC-R but i noticed exhaust escapes through the dump tube noticable since the tube echo'es it... it's not ALOT but it's there..


a)it's annoying and ruins the sound of my espelir exhaust..
b) i was under the impression the wastegate stays complelty shut until the very last moment.. and then just blasts all the way open... not bleed off..


i was considering tightening the arm more.. but that would also increase my boost.. which i'm trying not to do

 

[oldman]

You can tighten up the arm so the flapper won't get blown open as easily but you will increase the boost level at the same time. Why are you trying to run such a low boost on a turbo like that? Do you not have supporting mods? If you didn't do it for the dumping noise, why did you go with an O2 dump?

 

[Ottoman]

You can tighten up the arm so the flapper won't get blown open as easily but you will increase the boost level at the same time. Why are you trying to run such a low boost on a turbo like that? Do you not have supporting mods? If you didn't do it for the dumping noise, why did you go with an O2 dump?

my mods are:

Bullseye t3/t04b V-Trim
2.5->3" DP
Espelir 3.25" exhaust
Aeromotive aFPR
Walbro 255lph
DSMlink v2
huge FMIC
HKS SSQV
Injen intake
Oil cooler

Stock drivetrain/stock injectors

I just need injectors and that's it really...

I went external dump to prevent boost creep


dunno what kind of HP they can support....

dsmlink is still in the mail.. should be here next week... till then i want to keep the boost down so i can still drive it... it drives and runs ok.. but it fuel cuts at 0.83bar in top of 3rd or so...

i will try tightening the arm... i hope that works.. I'll check after work tonight

 

[oldman]

I went external dump to prevent boost creep

The Bullseye housing isn't known to creep, in any case dumping/O2 flow capacity isn't the main determining factor when dealing with creep therefore pointless in most cases.

but it fuel cuts at 0.83bar in top of 3rd or so...

Fuel cut implies too much air, not running out of fuel. You knock and pull timing when running lean. You hit fuel cut when your maf reading sky rockets causing ECU to think the wastegate is stuck closed, the intended purpose of fuel cut. Boost leaks on the other hand also causes sky rocketing maf reading hence the number one cause for fuel cut. You need to perform a boost leak test.

 

[Ottoman]

The Bullseye housing isn't known to creep, in any case dumping/O2 flow capacity isn't the main determining factor when dealing with creep therefore pointless in most cases.

That's true.. size of the WG hole/flapper makes a diff too.. that's why many ppl port it...
perhaps after sorting out this issues and the wastegate is functioning properly.. I'll chop off the dump and weld it closed...

Fuel cut implies too much air, not running out of fuel. You knock and pull timing when running lean. You hit fuel cut when your maf reading sky rockets causing ECU to think the wastegate is stuck closed, the intended purpose of fuel cut. Boost leaks on the other hand also causes sky rocketing maf reading hence the number one cause for fuel cut. You need to perform a boost leak test.

when IDC reaches 100% (or close to it) does the ecu not fuel cut? or it will just keep leaning out?

any idea what the approx HP the stock unhacked AFM can handle?


to be honest the car doesn't feel that fast to me.. it might be a boost leak after all... for some reason the car seems faster at partial throttle then at WOT...

 

[oldman]

when IDC reaches 100% (or close to it) does the ecu not fuel cut? or it will just keep leaning out?

IDC is calculate indirectly based on air flow, a TO4B-V doesn't flow enough to trigger fuel cut at 12-13psi (ever read someone creeping to 20+ psi with an EVO III before fuel cutting?) therefore the air count must be false. Pull your plugs, if you're truly hitting fuel cut due to fuel starvation, you should be running lean.... very lean, in which case you should be knocking like crazy if you had logging capacity. If you're hitting fuel cut due to false readings, you should be running rich....very rich.

 

[Ottoman]

IDC is calculate indirectly based on air flow, a TO4B-V doesn't flow enough to trigger fuel cut at 12-13psi (ever read someone creeping to 20+ psi with an EVO III before fuel cutting?) therefore the air count must be false. Pull your plugs, if you're truly hitting fuel cut due to fuel starvation, you should be running lean.... very lean, in which case you should be knocking like crazy if you had logging capacity. If you're hitting fuel cut due to false readings, you should be running rich....very rich.

Thanks Bruce, I appreciate the info...

i'll build a boost leak tester and check the system first chance i get...

 

[oldman]

No problem, good luck.