Wastegate line restrictor

[veeman]

The other day, a friend gave me a manual boost controller (think granger valve design) and I wanted to put it on my 1.6TD with stock Garrett turbo. I've got an EGT gauge and  had already blocked the blow off valve with a bolt per instructions I found here

Unfortunately, the barb connections on the controller valve are way too small for the Garrett wastegate hose (3/8"?).   I'll have to look around for some bigger barb / NPT fittings, but that got us thinking... what if we just put in a restriction in the actual line to the WG?

We took a piece of stainless tubing with the right OD and welded up all but a small orifice on one end.  I put it in the WG line on the turbo and took a test drive... 11psi (stock on mine is 10 psi).  Thinking that maybe the orifice we left in the adapter was too big, we welded it again and drilled it out to 1/16".  Took a test drive... 12 psi or maybe a touch more.  

Does that sound right?  I would have expected to see more of a rise in peak boost going from 3/8" hose to a 1/16" opening.   Am I missing something?     I'd like to be around 15 psi or so with a few pump tweaks to keep things relatively safe (stock HG and bolts).

[RabbitJockey]

you're going to need alot less than a 1/1th hole to get 15psi, just find a way to fit the mbc to the waste gate line, it might cost like 2 dollars in parts from an auto parts store, just need 2 adapters and a tiny bit of hose.

[arfalberg]

Small openings only restrict flow of air not air pressure.  it may time delay the WG opening and closing a bit but it should still get the proper signal eventually. if the opeing was extremily small it might work but it would be unreliable because somthing that small could be easily blocked by just about anything including a bit of oil, that would inturn skyrocket your boost untill the item became disloged, if it doesn't become dislogged you are running full boost potential till problem is relieved.

on the other hand, the manual controller only opens when the force of air is greater than that of the spring,  and once opened the WG gets instant signal to open, and instant signal to close once the valve has closed. i would stick to the manual controller for my money.

[veeman]

Last night, I ditched the inline restrictor and then found the fittings I needed to make the manual boost controller valve work on my stock turbo's wastegate line.  I couldn't change one of the 1/8" NPT barb fittings because it serves as the seat for the ball / spring, so I adapted the 3/8" wastegate hose to fit the barb.

Right now, I've got it set at a touch more than 14 psi.  I bumped in the fuel screw a little less than a quarter turn to help compensate.  The engine has a bit more power (and a touch of smoke)  but I remained conservative.  EGT's this morning on the long hill by work were around 1250 F or so max.  

I drive my caddy every day, so what's recommended for boost levels on a stock head gasket / stock bolts equipped 1.6TD?  I do have a full 2.5 inch downpipe and exhaust, but no IC as of yet.  I haven't touched the starwheel, but Hillfolk'r has given me instructions on how to do that...

[RabbitJockey]

i've heard of staying below 15psi with out an intercooler, but i have no intercooler and my waste gate is stuck shut and i have ventured up to 25 psi, and i have had no problems.  honestly i don't think boost pressure will really be doing any damage unless you have an already weakened headgasket, or if you running high numbers like 30+ psi,  but just tune your car in steps, and keep your exhaust gasses in check.  fueling is more of a concern than boost pressure.  

try messing with your lda reall turnning up your main fuel screw isn't for compensating more boost, that's the ldas job, and really it should be adding more fuel all on its own.  but adjusting it really makes a difference.  but go ahead and read on that in the faq, just remember to watch the smoking and watch the egt's