MagnaFlow Exhaust Systems

MagnaFlow Performance Exhaust Systems
Do you really need to install a performance exhaust system before adding power?
Does an aftermarket exhaust system really make a difference in dyno or towing performance?
Real-life testing is the best way to answer these questions.

Factory exhaust systems have improved considerably though the years, with mandrel-bent 3-1/2" or 4" tubing now being the norm. You've probably read quite a few exhaust system reviews through the years, and saw the rear-wheel horsepower improvement following the installation of a performance exhaust system. The installation photos were nice and the dyno numbers usually reinforce the notion that an aftermarket exhaust system allows the engine to make more power and help to provide a safety margin when installing performance products. What's the real story?

A well written test inclusive of what the average "Joe Duramax" will find with exhaust and power adder modifications. As you can see from my signature, I have similar mods and also pull a trailer. Thanks for a good evaluation.

Great article, Jim.

I have never upgraded a Duramax from the factory exhaust, but am considering doing so in an attempt to help with the turbocharger efficiency while towing, in summer temps.

Any cost effective mod that will help to dissipate heat from the overtaxed LBZ turbocharger is welcomed. Losing the cat is no issue here in MN for the time being, that should help as well.

Thanks again for taking the time on this one...

Of the exhaust systems that I have tested, I have seen more of a gain. More like 10-15HP. I don't think brand of the system has much effect, but could be wrong. I also don't think the 5" factor is that great, but now you have me scratching my head...

In my experience, how much of a gain the addition of a performance exhaust system makes sorta depends on how much extra power the engine is producing. When running stock power, the gain is small. When running a big program, the gain is bigger.

In addition to the performance bump, the fit and ease of installation are key items with the MF system. Stainless systems turning various shades of amber (moreso the closer to the engine) is the only downside to stainless. But a Mother's Powerball, metal polish and a couple minutes of your time will return the polished tip to shiny silver.... ;)

Jim

I probably should clarify. I think that the gains you saw were on the low side for exhaust, and not caused by the Magnaflow vs other brand. Any brand 4" exhaust will perform similarly with the key differences being as mentioned fit, quality, and sound.

My testing (again primarily with 4-5" systems) has shown larger gains and the tests have been performed with stock tuning same truck same day etc. Your low numbers could be related to the vehicle itself, local ambient conditions (elevation), or the dyno itself.

A well written article! This is a useful tool for any diesel owner. The comparison between stock and power numbers in multiple applications were very informative as well as the inclusion of EGT and boost numbers. Installation photos were also a nice touch.