Forced induction effects on MPGs

[Griepp06]

So I am about to pick up the gladiator 3.6 sport s max tow and planning on using it as my daily driver and towing vehicle. My current camper weighs 3000 lbs and my 96 Silverado that is being sold never had issues hauling it. I visit my brother in Colorado a lot and noticed at elevation my Silverado has a tough time for this gladiator I am considering a turbo or supercharger but don’t want to have negative affects for just normal every day driving as far as miles per gallon. For those of you that have done a turbo charger or supercharger what was the end result on your miles per gallon for normal day today driving? I have heard that it stays the same, gets worse, and can even make your fuel economy better. So very mixed reviews are out there.

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[Jefe1018]

It probably won't be good.

 

[Griepp06]

It probably won't be good.

personal experience cause you did it already or guessing? cause there seems to be an entire internet full of people guessing.

 

[Jefe1018]

personal experience cause you did it already or guessing? cause there seems to be an entire internet full of people guessing.

LOL, here we go. You ask a silly question then get upset when you get a silly answer.

FWIW, no experience with the 3.6 V6 in the JT, but I have turbo charged two N/A motors - it has not proven to be good for fuel economy.

 

[Griepp06]

LOL, here we go. You ask a silly question then get upset when you get a silly answer.

"mY mId-sIzE tRuCk D0s3n't t0W l1k3 mY fUlL s1z3, w1lL A tUrB0 h3lP anD n0t HuRt MpG?"

FWIW, no experience with the 3.6 V6 in the JT, but I have turbo charged two N/A motors - it has not proven to be good for fuel economy.

my questions was not silly and I am not upset I am asking for first hand knowledge and your original answer was very vague which is what i am trying to avoid. your second answer was better since you say you have added turbo's before. how much was the MPG decrease for just normal day to day driving?

 

[Jefe1018]

my questions was not silly and I am not upset I am asking for first hand knowledge and your original answer was very vague which is what i am trying to avoid. your second answer was better since you say you have added turbo's before. how much was the MPG decrease for just normal day to day driving?

That will be very subjective to your driving style, altitude, ambient temperatures, etc.

I boosted a sports car (twice because we blew the first engine, but more on that below), when the skinny pedal became more fun to smash, we found ourselves smashing it more and more.

Think about this, a super or turbo charger will many times require a bigger fuel pump, and bigger fuel injectors. More fuel in the ignition chambers = fewer mpgs.

Now as far as a 3,000lb camper goes, you should be fine stock. If the truck is rated for like 7600lbs, it can handle 3,000lbs just fine.

Have you also considered your warranty and longevity of a brand new truck? These engines can probably be put to a 'safe' boost point, but I'd think long and hard before doing that. If you aren't doing the work yourself, it also becomes expensive.

I've learned that many times you need to accept the limitations of the platform. You should be fine, this isn't a race truck it's a midsize Jeep first truck second. Its is just as a good as anything else in the segment at the moment and in my experience with the modern transmissions and engines in mid-size trucks, they tow better than even the full size pickups of the 90's.

 

[SteveInOrlando]

Ok, I will answer from Experience. My MPG went down, but I have still been working on tune so there is a lot more WOT than I normally would have. My average is just under 14MPG with a mix of around town and 70 MPH highway. I am putting 400+ lb/ft of torque to the back wheels at medium throttle around 3K RPM. You should ask in the thread https://www.jeepgladiatorforum.com/forum/threads/magnuson-tvs1900-kit-available-now.25396/. There are members on that thread towing with their supercharged engines, and running in the mountains.

I think Dave is getting much better MPG than I am getting, but my particular truck has always been finicky on the tune causing us extra time in tuning.

My sports car with a Turbo got better MPG as long as I stayed out of the throttle. It was much more efficient at low demand throttle than the stock tune was. That said, how economical a tune is, is very dependent on the quality of the tuner. Many tuners leave the mixture rich which is why boosted vehicles tend to have black muck all over the ass of their vehicle.


As far as the theory that the truck would pull ok in Colorado; I doubt it! Keep it locked down in gears maybe, but it is very underpowered and that doesn't improve with altitude. Plus that 3,000 lb trailer is empty weight. Add supplies/luggage and it will be considerably heavier.

You might try a re-gear. I hear members talk about 4:56 and 4:88 gearing with minimal impacts to MPG even at highway speeds.

 

[MEOIT]

I installed a Magnuson with Dave's tune. I am no regeared and am running 37's. My jeep is only used to run around town on the weekends and after work so my experience my not be very accurate. But my MPG for the life of my jeep prior to install was 13. After the install and tune I have averaged 14.8 in the first hundred miles. My driving is not stop and go city driving and more country driving where once up to speed you are at that speed for multiple miles.

 

[SteveInOrlando]

I installed a Magnuson with Dave's tune. I am no regeared and am running 37's. My jeep is only used to run around town on the weekends and after work so my experience my not be very accurate. But my MPG for the life of my jeep prior to install was 13. After the install and tune I have averaged 14.8 in the first hundred miles. My driving is not stop and go city driving and more country driving where once up to speed you are at that speed for multiple miles.

One other thing to consider, supercharged you will need to run 93 octane fuel. Super Unleaded can get pricey in some areas.

 

[mghoodlum]

Forced Induction can increase the efficiency of an ICE. In reality you will likely use more fuel due to the faster acceleration utilized (which ultimately is why you would install one).

 

[dcmdon]

So I am about to pick up the gladiator 3.6 sport s max tow and planning on using it as my daily driver and towing vehicle. My current camper weighs 3000 lbs and my 96 Silverado that is being sold never had issues hauling it. I visit my brother in Colorado a lot and noticed at elevation my Silverado has a tough time for this gladiator I am considering a turbo or supercharger but don’t want to have negative affects for just normal every day driving as far as miles per gallon. For those of you that have done a turbo charger or supercharger what was the end result on your miles per gallon for normal day today driving? I have heard that it stays the same, gets worse, and can even make your fuel economy better. So very mixed reviews are out there.

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[dcmdon]

Forced Induction can increase the efficiency of an ICE. In reality you will likely use more fuel due to the faster acceleration utilized (which ultimately is why you would install one).

Huh??

A supercharger introduces significant parasitic drag on the engine and at boost richer A:F ratios are used to prevent detonation.

How does that help efficiency??

 

[mghoodlum]

Huh??

A supercharger introduces significant parasitic drag on the engine and at boost richer A:F ratios are used to prevent detonation.

How does that help efficiency??

Of course the things you mention would reduce that however this is only part of the story. I can and may be fully offset and the some from some of the primary benefits of Forced Induction.

A normally aspirated engine cannot run at more than 100% volumetric efficiency, but a supercharged engine can, because it can pump more air than the displacement of the engine would normally permit. By reducing or eliminating the amount of force required to draw air into the engine, forced induction can simultaneously result in higher power output and better fuel economy. Finally, an engine that requires fewer downshifts can also result in better economy.

 

[ShadowsPapa]

Of course the things you mention would reduce that however this is only part of the story. I can and may be fully offset and the some from some of the primary benefits of Forced Induction.

A normally aspirated engine cannot run at more than 100% volumetric efficiency,

Actually, they can and do. We who have built engines have used that to our advantage.
Some of us are running carburetors for well over what should be "doable" - I'm running 1,100 CFM on my bored 360. The intake design, spacers under the carbs, headers, cam with overlap........ and I could do better with a modern design intake.

The design of the exhaust, the cam, the intake, all can lead to more air forced in than would be "pulled in". Tunnel ram, scavenging exhaust, etc. you have exhaust pulling intake in during the overlap time when both valves are open, and you have the intake valve not close until after TDC allowing the fuel mixture/air (which has mass) to continue in until the force of the upcoming piston overcoming the ram effect of the incoming charge.
It's actually more complex than that because the impulses generated in the intake manifold by other cylinders also can have an effect. Then we consider cross-rams, tunnel-rams, the plenum design of the intake, velocity stacks, whatever.

It's not impossible to get 130% on a NA engine.

I would suspect, an educated guess, that with a proper tune, a SC engine can be more efficient because you can use less throttle to achieve the same HP.
It takes xx HP to move a JT 70 mph on the level. If you can get that HP with less throttle, I'd expect no loss in MPG.
But - Dave can speak to that - the wizard of tune, the duke of supercharging, the Pentastar whisperer.......

 

[Aonarch]

How much is a FI swap realistically? $6-10k.

At that point who cares about a few hundred dollars in fuel a year.

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