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Running ‘free’: Another key to making turbo boost

Bruce Mallinson | March 21, 2014

exhaustEarlier this month, I wrote about free-flowing air and how changing your muffler, moving to dual exhaust and adding a second air filter can help your engine gain turbo boost and, in turn, make your engine more fuel-efficient.

If you followed those recommendations, you’re nearly ready to install a bigger turbocharger. First, there’s one more step you need to take.

To enhance the air and exhaust flow in your engine, install a heavy-duty high-performance ceramic-coated exhaust manifold. This manifold flows 20 percent or more exhaust than a stock manifold, and it will lower the exhaust gas temperature by 125 degrees; it also will not leak at the joints.


Gaining turbo boost: Start with a new muffler, then look at air intake

Instead of opting for a larger turbo, opt to make you engine run "free," by allowing better exhaust flow, writes Bruce Mallinson. That'll then yield ...

The extra exhaust flow will allow the turbo to spool up quicker, and the ECM will see the turbo boost sooner and release the fuel earlier.

This will create quicker acceleration, which will spur the engine to live longer, as exhaust gas temperature is lower and there is less soot in the oil. Also, your fuel economy will increase ¼ mpg.

Once this change and the ones we discussed in February have been made, your truck is ready for the larger turbocharger. You will feel the difference in performance, gain turbo boost, decrease exhaust gas temperature and even gain another ¼ mpg in fuel savings.

All of this brings you to a total of about 1 mpg difference – about $16,000 a year if you run 100,000 miles.

-Bruce Mallinson is the owner of Pittsburgh Power, an engine performance shop in Saxonburg, Pa. 

  • jimmyc63

    Mr. Malinson should know.
    Him and the crew at Pitts Power, are the best things to happen to trucking since 8 inch pipes and Alcoa wheels!

  • Big R Phillips

    I must admit that i too can testify that what he speaks is true. I have a 1996 W900L with a 3406 E Cat set at 500hp and i tell you guys if you havent taken that stock exhaust off, you dont know what your missing! First i installed the Air Cell which is one of the best investments i ever made. Noticeable difference as soon as the ECM dailed it in. The kitty had alittle growel to her.
    Then i called Pittsburg Power and got a 180° thermostat and threw that 210° in the bottom of a dumpster! Ohhh boy she stopped sweat’n and runs nice’n cool. But then i installed a Dynoflex performance muffler from 4States…(sorry Pitt Power) but i’m on a budg But maaaan let me tell you when i finally got a good load on her to see just what she’ll do with 45,000lbs of big roll paper outta Shreveport? It was about 2am and i was getting on I-49 north heading back to I-20 east right? Nobody was on the hwy so it was pretty quiet except when i mashed on Big MaMa and those stacks lit up and i was like “Ohhh Shit”!…lmao…and i kept catching gears and that Garrett turbo was singing so sweet ohhh my goodness i swear! The more i mashed the more she stuck her nose in the air. I hated to stop but i was outta hours thanks to Slow ass Pratt industries killing all my driving time. So i shut down at the Piltruckthats in Haughton,La. But i couldnt wait to get back on the super slab and roll after my 10hrs off duty. So for just those few changes i’ve improved my performance and mpg on a 20,000lb truck thats in the high 6’s per mile. 7 on flat land and set at 65 miles per hour with a fresh PM. Oh yeah i also run Mystic Synthetic blend 15w 50 oil. Freakin beautiful oil i swear! Cost alittle more but well worth it. Cats love that oil…lol. So thats my two cents and yall do whatcha want with it! The clock on the wall says thats all and i’m 10-7um and gone!

  • grandpa5x

    As an industrial mechanic with 35 yrs experience working with air, hydraulics, and lubrication systems if you have anything in the system that interferes with the flow of your exhaust(stock muffler, restricting bends, etc) or the standard single down pipe coming off the turbo, I don’t understand how JUST installing low restriction mufflers and dual exhaust will significantly improve flow. I agree from the split downstream restriction will decrease, but until the down pipe from the turbo to the splitter is improved that is the part that restricts you. strives to maintain an open forum for reader opinions. Click here to read our comment policy.