Ported intake manifold and MPG

[ScarabEpic22]

1) I didnt look behind there when we pulled my manifold off. Just pulled it, wiped the mating surface down with brake cleaner and a shop towel to clean the mating surface, then put it back on.
2) I cant answer your question as I have a RS, but it seems about half the people who've posted in this thread dont have an RS and are reporting good gains.
3) Sorry, dont know for sure. I dont think John (NewZJ) saw any detrimental effects from it previously. He has a 12 LT 1.4T 6M.


<Speculation> There's a chance GM put the restriction in there to kill airflow (power) at high RPMs and/or for emissions/EGR reasons.</Speculation>

I found out how hard the RPM limiter comes on when you're accelerating quickly (the ECM changes how hard the limiter comes on based on acceleration), and it was much harder than I expected. Just a pieced-together intake (thx John ) and porting the manifold made a big difference! Need to grab my HPT cable and change the limiter parameters when I tune it.

 

[Swordsmith]

I don't know if there is a difference in effect of porting on the RS vs the LT, but I suspect there is not. At the moment, we're still trying to determine if there is any effect on mpg at all; it sounds from reports in this thread that either there is none, or that there is a small gain.

The 1.4t Sonic is designed for and performs best on 93 octane, however they engineered a workaround to allow it to run on lower octane fuel; there is a knock sensor, and the ECU retards timing until knock stops. We think this is probably why we are getting better mpg (and more power) from 93 than from 87, while other cars, designed for 87, don't see any improvement with higher octane fuels, and still other cars, designed for 93 (or 92, or 91, more common fuels) see problems trying to run on 87 at all.

I haven't seen any reports whatsoever on emissions, but here's a theory; if the porting is improving mpg, then it is reducing emissions. Why? Because you are burning less fuel to go the same distance, and emissions are nothing but the leftovers after burning a given amount of fuel. Not necessarily correct; if you are burning less efficiently, there could be more emissions per gallon consumed... but it doesn't seem likely that you would get more power from less efficient burning.

 

[94383Z71]

Depends on how you looks at "efficient" though.

As most of us know, 14.7 AFR is stoic for gasoline. It is the point that complete combustion occurs, and in a perfect world utilizes every bit of air and fuel for 100% burn.

On the flip side, ~12.5:1 is usually considered best for max power. Essentially you are adding fuel to make sure the every bit of air and fuel that could mix and burn do, regardless is you use extra fuel that may not have mixed well enough to be properly useful-sorta like leading your target when shooting, but using excess instead of distance. More fuel=bigger boom boom. This is still close to a complete burn, but not like a stoic mixture (outside of extremes like big $$$ racing).

I must admit that the values for "complete burn" are as compared to richening or leaning out until the motor loses significant efficiency-i.e. runs poorly.

So technically 12:1 would be less efficient because you could use less fuel and still achieve complete burn, while of course producing less power. Emissions by mile are another discussion which I'm not well versed in.

Source: Airflow and Dyno courses at college, but a quick google shows Garrett saying most of this, minus the emissions implications.

Air/Fuel Ratio tuning:Rich vs Lean | Turbobygarrett

 

[ScarabEpic22]

Side note, GM changed the stoich AFR point on our Sonics (1.4T) between 12 and 13. 2012s are set to 14.7:1 while 2013s are set to 14.1:1. Why? Because E10 has a stoich of ~14.1:1! Everyone needs to be cognizant of this when tuning and/or monitoring AFR.

Shooting for 14.7:1 for light load/cruise on our (really all) engines isnt correct, you need to know what the tune is setup for...this is why lamba and EQR should be used instead as they are independent of fuel type (E0, E10, E85, etc).

Just something to be aware of and think about. Trifecta might have changed the 13 tune back to 14.7 but I have no idea, Im just looking at stock files in HPT.

 

[94383Z71]

I did not know that about E10 fuels. Good point!

 

[Scot]

The tumblers in the intake manifold are there for one reason, and one reason only: create a large amount of tumble in the intake charge to help vaporize fuel in a "cold" engine. This helps lower cold start emissions and keep precious metal content lower.

If you look at the typical EPA emissions cycle, 99% of the total pollutants come from the first 30 seconds of the test - on a 1375 second test! Poorly mixed fuel causes incomplete combustion, and when the catalytic converter isn't at operating temperature, lots of emissions exit the tailpipe.

When the engine is warmed up, the tumblers are not need; fuel is injected on the backs of the hot intake valves while they're still closed. This flashes the fuel into a vapor (and does a nice job of cleaning them too) and mixes readily with the incoming intake air.

They were most likely added because of how hard it is to heat up the catalytic converter on a turbocharged car. The best way to heat up the converter during a cold start is to use plenty of spark retard - the late combustion does less work pushing the piston down and much of the energy goes right out the exhaust port. Turbos LOVE heat, and will spool up - which removes energy (heat) from the exhaust before the converter can get all of it.

 

[ScarabEpic22]

Good insight Scot!

So what you're really saying is remove the cats and the tumblers REALLY arent needed...lol!

 

[Italianjoe1]

You can also turn off some of the cold-start tables usually if the car has them, I don't recall on the sonic if there are any. There is usually a cat-warmup section for retarding ignition timing based on engine run time.

 

[ecohauler]

I did notice a very slight drop in idle fuel economy when I ported my manifold. Tank-to-tank mileage seems about the same. I had just switched to high efficiency 0W-30 oil, and SGII was showing .15 gal/hr at warm idle, which was down from .16 with 5W-30. After porting the manifold, warm idle consumption went back up to .16. This is a very small difference, and due to rounding we only know that the difference is less than .02 gal/hr and greater than 0. Either way, it is not very big, and this engine still extremely efficient at idle, as well as under load.

 

[SoundWave]

I did notice a very slight drop in idle fuel economy when I ported my manifold. Tank-to-tank mileage seems about the same. I had just switched to high efficiency 0W-30 oil, and SGII was showing .15 gal/hr at warm idle, which was down from .16 with 5W-30. After porting the manifold, warm idle consumption went back up to .16. This is a very small difference, and due to rounding we only know that the difference is less than .02 gal/hr and greater than 0. Either way, it is not very big, and this engine still extremely efficient at idle, as well as under load.

Thanks for the data point, I've got one more tank of gas to burn up before I port my intake. Expect preliminary numbers in a few weeks.

 

[Kuntryboy865]

My mpg keeps increasing im at 37.9 right now

Sent from my SCH-S720C using Tapatalk 2

 

[SoundWave]

My preliminary results with just the BNR Stage 1 kit:

Hope to have time this weekend to port the manifold, should burn through at least 1 more tank of gas by then, maybe two depending on what shenanigans I get up to by Saturday morning. Note the Stock MPGs were over a dispersed period of time, mostly trying to get good MPGs, but not always. It's a decent sample of mixed driving, but not consistent Highway with cruise on driving like I'm doing right now.

 

[94383Z71]

Really glad you're putting forth real effort for good data- looking forward to the results!

 

[SoundWave]

Final pre-porting numbers are collected. I successfully ported my Intake on Friday night. I won't be including my first tank in the numbers as I spent a few hours beating on the thing afterwards just to enjoy it. I'll be filling up tonight/tomorrow morning and resetting everything to zero for the next round of data. Expect an update in three weeks or so.

 

[rsSteve]

Nice cant wait for some official results opcorn:

 

[cndctrdj]

Can't wait to see the results

 

[SoundWave]

Took a three-day weekend trip to Virginia Beach, so I burned few lots of gas fairly quickly. Which means preliminary numbers!

As stated earlier in this thread, my MPGs seems to be climbing consistently. The travel patterns mean I did more freeway driving with cruise on than typical, so we will see if the numbers dip over the next two weeks. Regardless, it's a definite improvement for minimal money!

 

[rsSteve]

Took a three-day weekend trip to Virginia Beach, so I burned few lots of gas fairly quickly. Which means preliminary numbers!

As stated earlier in this thread, my MPGs seems to be climbing consistently. The travel patterns mean I did more freeway driving with cruise on than typical, so we will see if the numbers dip over the next two weeks. Regardless, it's a definite improvement for minimal money!

Very interesting because this reflects my experience as well. opcorn:

 

[RMinNJ]

ported intake manifold affects

For MPG...you are comparing BNR tuned vs. BNR tuned+Ported Intake Manifold ?
It seems like the tune must play a role also to make use of the ported intake manifold?

I'm still on the fence on the porting as its not a reversibly mod and many folks over on the Cruze forum reported a low end torque loss that they could feel.
In theory if I'm revving the motor higher to overcome a lowend toque loss I should burn more fuel?

That many of the posts (both here and there) are tuned and untuned really
confuses the issue. From all my reading it seems like I should port the intake manifold somewhere half way to gain a little upper end power but not lose a lot of lowend torque?

 

[SoundWave]

For MPG...you are comparing BNR tuned vs. BNR tuned+Ported Intake Manifold ?
It seems like the tune must play a role also to make use of the ported intake manifold?

I'm still on the fence on the porting as its not a reversibly mod and many folks over on the Cruze forum reported a low end torque loss that they could feel.
In theory if I'm revving the motor higher to overcome a lowend toque loss I should burn more fuel?

That many of the posts (both here and there) are tuned and untuned really
confuses the issue. From all my reading it seems like I should port the intake manifold somewhere half way to gain a little upper end power but not lose a lot of lowend torque?

Yes, I'm stacking the mods, not removing them. As far as I know, porting the intake without a tune will cause significant issues, as the stock tune cannot handle the airflow changes. This is a reasonable real-world scenario for what everyone would do.
EDIT: I re-read some of the older posts in this thread, my statements regarding porting without a tune are wrong.

You may have missed my earlier post, so I'll summarize my testing: I commute 110+ miles a day, 95% freeway. I set the cruise for the speed limit as much as possible. It's obviously not a scientific study, but it's a good representation of what most people will encounter that do this.

If I were loosing low-end torque I would expect the opposite results, the speed limit on most Michigan freeways is 70MPH, which in sixth gear is just over 2K RPMs. That's as low end as you can get, so if the engine were working harder to compensate for a loss of torque I would expect I'd be seeing worse numbers not better.

Trying to "half port" the manifold doesn't seem like a good idea to me, airflow isn't necessarily a linear thing, and making the assumption that milling half the tumbler down will give you a specific result isn't a safe assumption. It's also very difficult to do free hand, and likely would result with airflow variances in each runner of the intake, which is very bad IMO. The ECU can only tune for overall airflow, not volumetric changes in air per cylinder.

Are there Dyno numbers to backup this loss of torque? Not being argumentative, it's just not something I've seen reported in this community, and at this point we have a pretty large sample size of results being reported.