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Hagerty Employee

Piston Slap: V-6 or turbocharged 4-cylinder for cost-effective cruising?

Not sure if this is the type of question you are looking for, but here it is. (We answer just about every question here at Piston Slap! - SM) I am considering buying a used Mustang convertible. I am interested in your comments on the V-6 engine vs. the four-cylinder turbo engine.

In have a question related to this topic. With a direct injection engine do you recommend an oil seperator or, for a normally driven car, is simply using top tier gasoline adequate to prevent carbon buildup on intake valves?

Adding to my own question for the community...i think oil separator is the answer as gasoline would affect exhaust valves, not intake.
Community Manager

If an oil separator can be easily installed under the hood of the vehicle in question, it's probably a good idea. If not, periodic cleaning using one of the many services out there will be more than adequate, and pretty cost effective if you shop around for the service (or do it yourself with a kit). 


I’ve owned both late model V6 and Ecoboost Mustangs and I agree with Sajeev. If all you’re worried about is reliability and costs, the V6 is the better choice.

That being said, the turbo 4 is no slouch of the line and can return very impressive fuel economy numbers if one is careful with ones right foot.

Well here is what I know on this having owned the GM versions of each.

The Turbo will get better mpg and more torque and feel much more sporting vs a NA V6

My V6’s are 310 hp by my Turbo Eco LNF was 300 hp but much better Torque at 315 ft lbs. if in a RWD they had 340 FT LBs.

Torque is what you feel not hp.

As for the direct injection and carbon. GM has cured this by putting in provisions to deal with it. My V6’s both post 2017 have a box in the in the valley that works like an internal catch can that never needs emptied. It eliminates the carbon issues the new Turbo 4 does something similar. My LNF never had a carbon issue.

You may check as Ford also may have addressed this as GM but said very little about it. The first clue was when the company making catch cans stopped at 20160 on the V6. I called and asked why and they said it was no longer a need for the revamped engine. 

I would recommend just driving both and see what you like the best. It is only for you to decide.


Ford and Toyota make pretty widespread use of dual-mode systems that are both direct- and port-injected. The port injection helps clean the carbon off the valves. I believe that, as of 2018, the 5.0 Coyote has such a system, as do all of the boosted V6s. I’m not sure why the boosted I4s do not have this setup.

Yes most companies have covered the Carbon issue by 2018. I am not sure of the Ford 4 cylinders but you may want to check out some forums to see if they have an answer. 


Some of the systems are pretty cleaver. The one in my V6 is great as it cures the issue and it works well with little add on bits. It did take a new block. Most do not realize that the old GM 3.6 is not the same as the new. They redid the entire engine. It needed it. 


As for Turbo engines most are very reliable. I used to hate a turbo till I owned one. After 10 years I loved every minute of it. The only thing that was wrong it was a FWD that limited traction. I could set off the traction control up over 50 mph. 


I know not all turbo engines are equal so it should be investigated. Mine was the Ecotec that with the GM tune had 23 PSI of boost and it never gave me a bit of trouble. 

Advanced Driver

At what age do you move past performance and into reliability? I'm 75, and it hasn't happened yet.

If I was buying another Mustang, having owned 2 so far, the V8 is still the only choice. Neither the V6 nor the turbo 4 has the sound of the V8.

One of the best ways to predict reliability is to look at the charts in Consumer Reports. They have the largest and best public database on reliability. If I recall, the V8 Mustang was somewhat more reliable than either the V6 or the 4.

Keep in mind that for the S550-chassis (2015+) Mustang, the V6 was only ever installed in plebeian, fleet-spec models. I’m pretty sure that even to upgrade to MyFord Touch or SYNC3 over the base infotainment required upgrading to the EcoBoost. Which is reason enough to disqualify it in my mind.

Also, the V6 was unceremoniously discontinued after 2016.

Last year we evaluated both engines and opted for the 2017 , the last year of the V6. Our obsevations: The econoboost 4 is a great lawnmower engine. It requires a 10 speed auto because of its severely narrow torque curve. Driving it, the computer is constantly seeking out the best gear to the point of being annoying. While on paper the V6 appears less powerful , driving it gives you a feel of more power. We drove 3 different Ecoboosts to confirm that our impressions weren't a one off. And looking at the reliability, the V6 wins hands down. Gas mileage in daily driving is very close.