I just bought this truck and I do not think Im getting the max turbo boost. I have gauges and Im reading 14 is that what I should expect or should I be getting more. My truck is stock.

 

14 is a little low. The stock 99+ psd's usually get into the upper teens.

How many miles on the truck?

 

i've seen my go into the 20's on my 99 with 240miles on it

 

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Welcome to the forum Kelsokell.
You might have a mis-adjusted wastegate. Look on the upper rear of the turbocharger and you'll see the wastegate lever and control rod. You'll need some sort of way to pressurize the control canister. Shop air, bicyle pump, anything that will give you about 20 PSI.
Buy yourself a spare c-clip, 99% sure to be lost into the black hole where all the spare socks go in the laundry.
Remove the little c-clip from the lever. Pressurize the canister and see the lever move. At that point you can very easily lift the control rod from the wastegate lever. Adjust the rod shorter by a few turns. You can shorten it down all the way if you want and no harm done, lot's of guys do it.
Re-pressurize the canister and re-attach it to the wastegate lever. Don't attach the c-clip just yet. Leave the wastegate control line disconnected from the control canister and go test drive.
If you don't have any other problems you'll notice an immediate increase in boost pressure.
If you are satisfied with the results, restore everything back.
Optional: Don't reconnect the wastegate control line, instead just leave it disconnected. Cap it off and enjoy even greater boost.

 

One question that comes to mind is your truck an early 99, build date xx/98? or late 99. Mine is a pre 99, I have a 6637 air filter rather than the stock filter, commonly known here as the Kwik filter. I can easily get 20lbs of boost, I have seen it up to 25-26 multiple times, usually setting the SES light for overboost. Have thought about adding a boost relief valve, but if it starts to defuel it is also kinda like a built in EGT limiter. Have no idea what it reads with a stock filter as I replaced the filter before getting gauges.

 

just a thought, i am not for sure if i understand everything yet about this surge and stall situation, please set me straight. my stall started after the 6637 and large exaust.Is it the big filter allowing more air, the biggest causeof the problem?more air ,running too lean,and the wheel pulling too much air. I know this sounds stupid but if you were toblock say part of that filter, would that help the stall problem by not allowing it to suck so much, just enough to stop the stall?

 

Texas_vet, this was posted awhile ago by another member:

Turbo surge (aka compressor stall/surge or turbo bark). This happens when say you are running with high boost and get off the throttle suddenly. What happens is the drive energy the exhaust wheel needed to keep the compressor making 20-25 psi is lost. Now the engine has a greatly reduced demand for air. The 20-25 psi in the intake is now not needed by the engine but has to go somewhere. The only place for that pressure to escape is back out of the intake (yes it goes back the other way) past the compressor turbine blades. When it goes throught the blades the turbine will slow down very, very quickly. The turbine will not stop or spin backwards, the exhaust is still flowing past the exhaust turbine. The sudden slowdown of rotation is called compressor stall/surge, the noise it makes is called turbo bark. The bark is more noticeable with an intake and is even more noticeable when running hot (chip, tuner, power module). Compressor stall/surge is bad for the turbo, the sudden change in rotation speed can damage the bearings or even worst case - snap the shaft between the exhaust and compressor turbines.

BTW for reference your turbo can reach speeds up to 150,000 RPMs, thats 2333 revs per second. The rotational forces in a turbo are tremendous.

posted by jrs_big_ford_f150 (like to give credit were credits due)

You do not want to block part of the air filter. With diesels you want more air in and more air out. "Let them breath" as they say. More air in allows for better/more complete combustion. More air out allows the hot gases to leave easier/more quickly lowering back-pressure against the turbo and cyclinder exhaust, and lowering EGTs. The culprit is the higher boost especially from chips/tuners. Larger intakes and exhaust do not increase your boost. They "allow" higher boost by having more fresh air available and reducing exhaust back-pressure. Adding more fuel via a chip/tuner increases the boost. Simplified, more fuel equals more exhaust pushing against the exhaust side of the turbo, spinning it faster, thus more boost. Disabling the waste gate also allows for higher boost by disabling the process to limit the boost. You may just hear the surge/stall better because of the larger intake and exhaust.

The recommended cures for turbo surge (99+ PSDs) are a "wicked" wheel (WW) turbo wheel where some (I believe alternate) turbine air intake blades are lower than the rest of the turbine blades. This allows the air trying to escape backwards through the turbo, as explained above, to pass without pushing against all the turbo blades going in the opposite direction. This does not cure all of the turbo surge (cause you still have some pressure against the taller blades and that portion of the lower blades), but most of it. I think wicked wheels cost about $60, installed yourself.

The other recommended cure for turbo surge is a "vented" turbo housing, aka ATS housing, which I believe allows the backwards moving air to vent verses pushing against the turbo blades. I think a vented turbo housing runs about $425. Abit pricey for most people and not as easily installed as a WW, but it's said to completely cure turbo surge/stall.


Disclaimer; If I'm wrong on any of the above, someone will come along and correct me and we'll both learn something. Long posts are from boredom and trying to help a fellow PSD owner.

 

Thanks Stroker 2, I think I got a grasp on it now.

 

Thanks for the tips I will adjust the waste gate and see what my turbo boost is after. My truck was made in 2-99 I have 174,000 miles on it runs great I just would like to get a little more power I will be doing some mods real soon.

 

gauges first if you don't have them already... upgrade your air intake, then the exhaust, then you are ready for a tuner or chip to dump more fuel and make more boost and more power...! this is the order most of the guys in here reccomend and i agree... also... if you have an auto tranny... get the sonnax kit and add a BIG tranny cooler to the stock setup..!

 

wouldn't a Blow off Valve 'solve' that problem?? All the custom turbo (4 banger) that i know of have a blow off valve to release such pressure when u let go the pedal and when shifting.. This way, the compressor wheel never gets to see negative flow.

Or, is this not done on diesels?

 

No need for one on a diesel. Diesels don't have a throttle plate to close and build up boost behind.

 

even if we dotn have throtle plate boost still creeps once we let off the pedal, soem goes into the combustion the rest flows back to the turbo.

whats easier to install? wicked wheel of bov?

 

I'm thinking the w/w since I have never heard of a bov on a oiler.