Wasted Wastegate? Low boost diagnosed. NOW WHAT?

[dpantazis]

i have been chasing what i thought was a boost leak for a while. i crunched one of the sheet metal plenums doing boots recently. i repaired the plenum and added a reinforcing ring to make sure it does not happen again. i used hairspray on all boot connections. i used hi-tack on the plenum that i repaired. upgraded boots and clamps all the way around.

i made up a pressure tap with PVC pipe, regulator and valve. i can pressurise the the whole intake system from the air cleaner. no leaks.

i am still getting 20 psi boost MAX at WOT. 80+ on the highway. mileage with 80hp ECONO tunes are 16 mpg. pre-chip was about the same. rest of the mods in sig.

i call jody and describe it all to him. he suggests unplugging the wastegate to see what if any effect it has.

jody says to check for exhaust leaks too. no exhaust leaks seen, actually no soot trails seen.

unplug red tube, plug it, go for a drive. engine is hot so as to eliminate the EBPV being closed.
WOT boost hits 25-27 psi before i run out of road.

so turbo can make more boost. wastegate might not be working right.

NOW WHAT?

dennis

 

[Got Diesel]

Dennis sounds like you need to adjust your wastegate rod. I believe turning it clockwise shortens it. It's opening up at too low of boost.

 

[dpantazis]

i was just thinking that and came back to edit my post on that very thing.

can the rod be adjusted? how? instructions or threads anywhere?

how do you know at what pressure it starts opening at? what about stops for max?

dennis

 

[whatabudro]

Nothings broke Dennis. It's all working like it should. I'm assuming by your sig that you only have an 80 hp tune? 20 lbs boost is fine and quite normal. You could spend the money if you choose to upgrade your wastegate and see higher numbers. My stock turbo used to do about 25 lbs on the extreme settings and I was happy with it. I upgraded to the 38R and saw the same exact numbers. I adjusted the wastegate on my new turbo and now see 32 lbs @ WOT but it's rated for 40 psi also. The stock turbo loses it's efficiency after 25lbs and I just don't think the money you would spend on a new wastegate would be justified.

 

[whatabudro]

i was just thinking that and came back to edit my post on that very thing.

can the rod be adjusted? how? instructions or threads anywhere?

how do you know at what pressure it starts opening at? what about stops for max?

dennis

By shortening the rod you will put more pressure on the spring making the flapper harder to open.

Adjust, test run, adjust, test run......

 

[roosterdiesel]

WG is working fine. The solenoid allows 5lbs(I checked with my gauge) of boost through the redline to the actuator to open the WG slightyly and help relieve back pressure. Tightening the rod adds more preload which allows higher boost capabilities. With the econo tune people see 25psi easily, I do with no WG.

Crank the rod down! 6 turns should be around 24-25psi.

 

[dpantazis]

thanks for the info guys.

i am not looking to super-soup up my truck. only reasonably unleash the true spirit within and squeeze out a few more mpgs. i want this truck to last too.

i really don;t expect to run the truck at WOT much- so i really don;t care if it ever sees anything over 30 psi. around here, you run out of road real quick. i ran the stretch of 137, Anshutz Expy in waukega for my testing at 5 am. it is pretty much abandoned since johns manville closed the asbestos plant. from a standstill i flew through the 1.5-2 miles pretty quick. hat i should really do is find a dyno day somewhere to do a few dyno runs.

running the WG unplugged gives me the willies. i need to read up more on it. my understanding from jody was my 20psi was propably affecting my mileage. more of a general health issue than a specific symptom.

tuning the actuator makes more sense. by moving the operating range of the opening of the solenoid, that may solve my problem. so for now, a few turns of the screw and a road trip to see what it does.

thanks again for your help

dennis

 

[dpantazis]

i met up with the folks at midwestoilburners.org yesterday. i spent some time talking to dale (some of you may remember the guy with the white X that was at BTS open house).

i talked to him about my issues and he was surprised that i am running a chip w/o some sort of boost relief valve or regulator to the MAP. he also thought that it was curious that I have not gotten a SES light with all of my 'testing' trying to get the boost over 25 psi- overboost/defuel.

now i am starting to wonder if the MAP is flakey. any checks on the map short of changing it? i am also going to try rigging up my FP gauge like TG.

dennis

 

[roosterdiesel]

now i am starting to wonder if the MAP is flakey. any checks on the map short of changing it? i am also going to try rigging up my FP gauge like TG.

You can get a scan tool that reads PIDs and see what the MAP sensor is reading, remember it reads atmospheric pressure too so you'd have to subtract that from reading. If it coincides with your boost gauge then I would think the MAP sensor is fine.


If your WG is set to open at 20ish psi then the MAP would never see an overboost situation. I don't remember how long you have to be over what ever reading(trucks are different) to set the SES light. People say it's somwhere from 22-25psi. The truck is in max fuel tables starting at 17psi so most people set up regulator style setups to 22psi.

 

[dpantazis]

FLAKEY MAP!

got new map this week, and put it in today. same fuel, same chip setting, unmolested wastegate.

warmed up, WOT hitting 25-27 psi on the boost gage. now its time to come up with a regulator. hoping i can do it before i leave for 10 day 3000 mile jaunt.

dp