I have a '04 350. I have replaced the stock air intake with a AFe cold air intake, and straight piped the exhaust. At a stand still the turbo lag is bad 10 sec before is builds up boost. I have heard that the veins in the turbo will get sticky, and not open up like their designed to do. What is the fix for this problem? Without having to replace the turbo..

 

20x,

First off welcome to FTE, lots of good people and info around here.

From a dead stop you will get turbo lag. If you power brake you can launch from a dead stop.

If you do have sticking turbo blades, there is a cleaning procedure outlined by FMC. If the cleaning procedure does not work then turbo needs to be replaced. Also the VGT actuator may not be functioning properly.

Also when you straight piped it did you start at the Turbo? If you increase the downpipe beyond 3.5-inches in diameter you will lose some low end power. Also a larger exhuast pipe reduces some low end power, especially if you get above 4-inch diameter.

I am guessing you are outside your 5/100K warranty.

Sorry to here you wasted your money on an A/M air intake for the 6.0. The OEM Donaldson is the best unit going until you reach 500+RWHp. The OEM Donaldson unit supplies more air than the 6.0 can use in stock and mildly tuned (below 500+RWHp) configurations, and filters better than anything on the market.

 

In a nutshell u remove the turbo and inspect the vanes....remove them and sand down the unison ring if rusted or gummed up...this should prevent any sticking condition.

 

Here is the step by step procedure to clean the turbo if you want to try it yourself.
http://www.forddoctorsdts.com/articl...icle-06-05.php

 

One other thing which could do this is..... a fuel filter problem (getting plugged). I had what you described and just changed filters and now just a small lag but ohhh the power even stock.

 

No, you do not lose low end pressure on a turbocharged vehicle when using a free flowing exhaust. This is only true on naturally aspirated motors.

 

What type of engine oil do you use? Synthetic or dino. From the problems you are having, I suspect dino. Dino oil will "coke" or cook and coat the vane actuators with burnt oil causing them to stick or fail to move all together. With very hot exhaust gases flowing over the variable compressor vanes, dino oil will cook especially if the motor is shut down right after a real hard pull with constant high EGTs. I believe the #1 failure of 6.0 turbos is compressor variable vanes sticking. The rust that people talk about is probably cooked oil on the vane actuators because they look very similar. If it was actual rust the vane area where the rust collects would show some pitting. On the other hand, cooked oil will come right off with no visible pitting.

If you use sythentic oil, it will not coke or cook. I would really like to survey the 6.0 guys on this site to see who has had turbo and fuel injector problems and find out what type of oil they use. That should be a very revealing survey and probably one FMC might be intertested in the results. I would guess that the dino guys have far more turbo problems then the guys who use synthetic motor oil.

After that long winded disertation, and if you are using dino oil, I would suggest you change over to synthetic and see if the turbo lag problem gets better. I have used Royal Purple synthetic lubricants for years and have had no problems in any vehicle. I have 48,xxx miles on my X and have no turbo or fuel injector sticktion problems.

Hope this helps!

DSMMH

 

Sorry but you do lose low end power with too large an exhaust system on the 6.0 & 6.4 this has been proven out many times by the guys that race these trucks. The power band shifts up. You gain top end perfromance but lose some bottem end performance.

 

I have a hard time beleiving that but hey, anythings possible.


As for my Subaru STi, it has been dynoed with only the DP and with the turbo back with no loss of low end power (minimal gain of 2hp w/o from 1.5K on up).

Maybe it has something to do with the VGT turbo?

Jake

 

Well the Diesel 6.0 or 6.4 is not a Subaru STi "Gas Engine". Many many things effect the way an internal combusiton engine works and performs, be it naturally aspirated or turbo/super charged. Many things effect were the Hp & Torque fall in the power band, and naturally aspirated or turbo/supercharged is only one small part of the equation.

You make a change in an internal combustion engine and it is going to effect other things. These may be desireable effects or non-desirable depending on the conditions that need to be met.

 

I understand engine dynamics.

Do you have any links to show that the 6.0L loses bottom end power (i.e., power band shifted upwards) after installation of a larger (uncatted) downpipe?

 

Id have to disagree.....synthetic oil has min advantages over dino(specially w/5k change intervals)....if u use CJ4 or eqiv oil...u will be fine...the motor (6.0) was factory fill with dino and was built and test ran with dyno....In fact if that was the case ford would reccomend it in the manual. cheap fuel and no additive would be a more likely cause IMO for turbo issues rather than oil.

 

Just search for the posts by Matt (PSD 60L Fx4) as the data is there or call and ask him. www.lideisel.com.

This has been posted and confirmed by numerous people who race the 6.0.

Also read some of the drag racing forums on the net, header length, size & bends, exhaust length & size effect the power band. Exhaust scavenging is effected by backpressure. Too much or too little effects performance and the range of the power band.

 

Thanks blackhat.