Effects of a TMIC upgrade on fuel economy

[moleodonuts]

I am getting the itch to mod but drive nearly 100 miles/day. As such I'd like to stick to mods that keep my fuel economy similar or better to what I currently get.

My question is, does anyone have any info on how a TMIC upgrade affected their fuel economy? Not that I need well thought out scientific tests... just general impressions work for me. (cabpatch)

 

[InlineTwin]

Nothing. If that is the only part you install you will see no change in power or fuel efficiency.

 

[Abaddon]

Theoretically... it shouldn't effect fuel economy at all... if anything, it will improve it.... but not enough that you should notice it.

All you are doing is lowering the temperature of incoming air. This makes the charge denser (more oxygen per cubic foot). So it needs less air for the same stoichiometric reaction. To get less air volume into the chamber, you will close the throttle a bit (we are talking fractions of a degree here).

Then again.. the air is cooled after the throttle plate, temperature sensors, etc... so would the system really notice a change? Possibly though the Oxygen sensor... but either way.. cruising along at a steady speed, there is a specific torque requirement; Which translates into a certain mass of fuel per cycle; which is a certain volume of air required to burn said mass of fuel...

IMHO... your throttle position may change (slightly: I don't think you would notice) but the fuel sprayed into the chamber will not. So, you SHOULDN'T get a change in fuel economy.

Now.. on a Diesel.. that's another story...

 

[Speed_Racer]

at part throttle and intercooler wouldn't effect fuel mileage considerably either way. if it flows better (ie bar and plate or lager cores) then maybe the engine can breathe a little easier. I dont see it makeing it anyworse.

 

[Diamonddog]

I am getting the itch to mod but drive nearly 100 miles/day. As such I'd like to stick to mods that keep my fuel economy similar or better to what I currently get.

My question is, does anyone have any info on how a TMIC upgrade affected their fuel economy? Not that I need well thought out scientific tests... just general impressions work for me. (cabpatch)

I also drive about 100 miles a day. I installed a 3.25" TMIC about 2 weeks ago and have had no change in my mpg.

 

[Abaddon]

Quick Question....

If you guys are driving 100miles a day... why don't you have a diesel?

 

[speedi3]

Your gas mileage will go down as you will get on it more!!!! The added torque has been better than any other mod that i have seen.

That said I haven't seen any improvement etc.. I have more miles on the car than anyone at 18,000 since Nov. and the mileage has held except with the CAI.

 

[moleodonuts]

Quick Question....

If you guys are driving 100miles a day... why don't you have a diesel?

I'd really like to, but there aren't diesel compact cars that entirely fit what I want in a car (reliability, mild performance, and space to haul around my bikes and kayaks and all).

 

[Haltech]

Intercooler upgrade is to cool the incoming air more efficiently.Therefore, a fuel economy increase wont be on your side. If anything, youre going to gain more power and torque, causing your fuel economy to go out the window when you start getting on it. Turbo/Supercharged cars arent your best bet for fuel economy... Thats what diesel is for!

 

[moleodonuts]

Intercooler upgrade is to cool the incoming air more efficiently.Therefore, a fuel economy increase wont be on your side. If anything, youre going to gain more power and torque, causing your fuel economy to go out the window when you start getting on it. Turbo/Supercharged cars arent your best bet for fuel economy... Thats what diesel is for!

If I'm more efficiently using my system by getting a more efficient IC (less lossy or one with better heat transfer) and thus getting more work per cycle, my power demand should be the same, right? So aren't you saying my fuel economy would go up? I'm confused (uhm)

EDIT: by "less loss"y I mean less of a pressure drop across the heat exchanger; that didn't look clear when I re read my post.(burp)

 

[Haltech]

If I'm more efficiently using my system by getting a more efficient IC (less lossy or one with better heat transfer) and thus getting more work per cycle, my power demand should be the same, right? So aren't you saying my fuel economy would go up? I'm confused (uhm)

EDIT: by "less loss"y I mean less of a pressure drop across the heat exchanger; that didn't look clear when I re read my post.(burp)

How is it going to go up? Youre lowering the cooling charge of the boost. During normal driving, youre not going to see the efficiency like you would at full power. Keep in mind, youre not in boost at all in normal driving conditions.

If you want more mpg, you need to lean your car out in the fuel map. This is why the CAI works for increasing fuel economy. It leans out the fuel charge by getting more dense air, in larger volume to the engine.

 

[Abaddon]

If you want more mpg, you need to lean your car out in the fuel map. This is why the CAI works for increasing fuel economy. It leans out the fuel charge by getting more dense air, in larger volume to the engine.

Isnt that the definition of what an intercooler does...? Well.. it wont lean you out, because the O2 sensor will compensate by cramming in more fuel.. but still...

 

[moleodonuts]

If I lower the cooling charge, won't I get more power at a given engine speed (and in our case, a given gear)? That way, if I assume I'm cruising at one speed with the stock IC and it requires a specific power demand to keep that speed, which has some associated hypothetical throttle position and gear. Then, if I switch to the new IC and my charge becomes cooler and thus the air is denser, won't the O2 sensor then respond by increasing the fuel delivery, thereby increasing the power output and then the car will accelerate at that given gear, throttle position, and speed?
So to keep my cruising speed I would have to back off the throttle.

I would think that's the same reason a CAI increases fuel economy- the pumping losses are reduced and the charge temp is reduced so you get more 02 in at a given set of conditions- O2 reads this, ECU has to deliver more fuel to keep the cat in its window of efficiency and so you get more power. Again requiring us to back off the throttle.

What's the functional difference between a better IC and switching to a CAI? I feel like I'm missing some bit of information, or I have some major misconception. (stash)

Again, I am just trying to think this through and make sense of it. I'm responding only to try to grind out an understanding on how this all works. (braindead

 

[moleodonuts]

Isnt that the definition of what an intercooler does...? Well.. it wont lean you out, because the O2 sensor will compensate by cramming in more fuel.. but still...

yeah yeah, much better way of saying what I was trying to say (puke)

 

[Haltech]

Isnt that the definition of what an intercooler does...? Well.. it wont lean you out, because the O2 sensor will compensate by cramming in more fuel.. but still...

Do you have some kind of magic o2 sensor in your car that the rest of us are lacking? If that was the case, why do we need to modify our fuel, timing and maf trims to compensate for more boost and mods?

A stock non wideband system can only do so much for a car.

The guy wants better fuel economy.. an intercooler isnt going to do it for him. He needs to lean out the a/f mixture in his tune.Simple as that.

 

[Rotus8]

Do you have some kind of magic o2 sensor in your car that the rest of us are lacking? If that was the case, why do we need to modify our fuel, timing and maf trims to compensate for more boost and mods?

A stock non wideband system can only do so much for a car.

The guy wants better fuel economy.. an intercooler isnt going to do it for him. He needs to lean out the a/f mixture in his tune.Simple as that.

Well, the stock O2 sensor #1 is a wide band.

 

[Haltech]

Well, the stock O2 sensor #1 is a wide band.

Are you sure about this? Provide me a source for your information. If thats the case, tuning these things would be a breeze...

 

[moleodonuts]

that's what an O2 sensor does. The ECU requires a certain A-F ratio and the o2 sensor either gives out voltage or does not (on or off) and the car must constantly rise and fall above that air fuel ratio.

A wideband O2 sensor changes this by sending out a signal that tells you more than just if your are rich or lean of your mark- it will tell you by how much, or you can take that data and turn it into your actual instantaneous A-F ratio.

Can we actually lean out the A-F ratio without altering the function of the control system? What else is the O2 sensor doing if not to give the ECU the information it needs to adjust the A-F ratio?

 

[moleodonuts]

If that O2 sensor is a wideband, then it would make more sense how the ECU can change what A-F ratio it looks for across the power band. Last time I studied and worked with automotive control systems, the O2 sensor had a built-in set point that it would either be above or below (on or off/voltage or no voltage). Any change in A-F ratio across the power band was just a quirk or limitation of the control system and its inability to respond at the rate the engine is turning.

 

[SSMS3]

3.5" TMIC ETS, no change in fuel economy, computer or calculated. Added power by SOTP but no dyno to back it up