Significant Gains from Manifold Porting

bahndrvr · Jun 15, 2018

KTuner said:
Did you happen to compare MAF values? That would tell you directly how much air you're bringing in.

I will log like hell when I do it - using your v1.2;-) It will be a while for me though - the OP doesn't have that car anymore from what I read that lead me to this thread - he has moved on to a different civic IIRC. For me and my massive commute I will be logging as I can't afford to loose gas mileage, hence me not doing it on my current intake on my Si, will only do if I can source a used stock one for cheap

LilToTo17 · Jun 15, 2018

bahndrvr said:
Only reason I asked is it showed an improvement on the 2.0 removing the fin in the manifold - i have experience removing it and having good results as well. If I can source a cheap stock intake manifold I will modify it and put it on - probably so some low level porting as well on the entrance paths if necessary. That's ONE part of the equation - and yes it's on the back side of the engine In all honesty there are newer civics in my local pick and pull and they have 25 dollar all you can carry days - i can get the manifold and other items for 25 bucks then take the time to port and it would cost my 25 bucks plus new gaskets an time only. I WILL do this.

For the front side - the pancake of the stock plastic pipe bothers me, this is a bottleneck once power starts to go up and it creates a bit of turbulence and disruption of flow, not a big deal on stock intake setup and power, but when you add more power, more boost, better intercooler and intake it will allow for more air. If cheap I would try this as a separate item and of course there are tons of ways to reduce the heat soak on the metal as opposed to composite going across the top of the turbo. These are all ideas for little tweaks and improvements only till I'm over 100-120k miles and when i throw a larger aftermarket turbo setup I looked back in Nov/Dec an noone offered an aftermarket solution, so revisiting a bit due to this thread discovery

Anyone can throw random parts at a car, but maximizing what you have and complimenting mods with other mods is how i roll

Damn very informative lol and excited to see how it turns out!

Myx · Jun 15, 2019

bahndrvr said:
Only reason I asked is it showed an improvement on the 2.0 removing the fin in the manifold - i have experience removing it and having good results as well. If I can source a cheap stock intake manifold I will modify it and put it on - probably so some low level porting as well on the entrance paths if necessary. That's ONE part of the equation - and yes it's on the back side of the engine In all honesty there are newer civics in my local pick and pull and they have 25 dollar all you can carry days - i can get the manifold and other items for 25 bucks then take the time to port and it would cost my 25 bucks plus new gaskets an time only. I WILL do this.

For the front side - the pancake of the stock plastic pipe bothers me, this is a bottleneck once power starts to go up and it creates a bit of turbulence and disruption of flow, not a big deal on stock intake setup and power, but when you add more power, more boost, better intercooler and intake it will allow for more air. If cheap I would try this as a separate item and of course there are tons of ways to reduce the heat soak on the metal as opposed to composite going across the top of the turbo. These are all ideas for little tweaks and improvements only till I'm over 100-120k miles and when i throw a larger aftermarket turbo setup I looked back in Nov/Dec an noone offered an aftermarket solution, so revisiting a bit due to this thread discovery

Anyone can throw random parts at a car, but maximizing what you have and complimenting mods with other mods is how i roll

@bahndrvr Have you done this modification yet? I just ran into this thread today. Had I known about this when I was modifying my 2015 Honda Fit CVT, it could've very well had me edging closer to the 14 second 1/4 mile range. A 6% change in injector duty cycle is significant. Does this mean 6% more fuel was added due to 6% more air was measured coming into the engine?

Big thanks @DARK SiDE for sharing this.

Jpierro79 · Aug 20, 2019

For those looking to modify it to have a second one Incase of back up it’s literally 75 dollars brand new.
17100-RPY-G01

bahndrvr · Aug 23, 2019

Myx said:
@bahndrvr Have you done this modification yet? I just ran into this thread today. Had I known about this when I was modifying my 2015 Honda Fit CVT, it could've very well had me edging closer to the 14 second 1/4 mile range. A 6% change in injector duty cycle is significant. Does this mean 6% more fuel was added due to 6% more air was measured coming into the engine?

Big thanks @DARK SiDE for sharing this.

No - shortly after this picked up a dedicated drag car, my car doesn't even have a tune on it anymore! Just modded intake with PRL stage 1, eibachs and rear camber arms. Everything else is back to stock, and will be selling my wheels and tires, and suspension stuff I have soon as will be getting back into a truck to tow my drag car.

Gradyjim024 · Jan 21, 2020

So what tools did you guys use to remove the divider? Did you have a custom tune like right after modifying it? Just trying to figure out if it would be safe to run it to NC from GA with it to go get a tune. Thanks in advance

Myx · Jan 21, 2020

I forgot all about this. No-one has made any moves on this yet eh?

Gradyjim024 · Jan 21, 2020

Well I just dremeled down the divider definitely not as pretty as the original posters but itll get the job done.

Gradyjim024 · Jan 21, 2020

Went a little excessive with the dremel.

Honda Civic 10th gen Significant Gains from Manifold Porting Snapchat-349293787

Honda Civic 10th gen Significant Gains from Manifold Porting Snapchat-696162448

salik990 · Jan 22, 2020

Gradyjim024 said:
Went a little excessive with the dremel.

do u have to retune again after removing divider? hows the response of the throttle?

Gradyjim024 · Jan 22, 2020

salik990 said:
do u have to retune again after removing divider? hows the response of the throttle?

I haven't went and got a custom tune yet so I won't know until then. It should be better at WOT.

Myx · Jan 23, 2020

Jpierro79 said:
For those looking to modify it to have a second one Incase of back up it’s literally 75 dollars brand new.
17100-RPY-G01

Just checked this for my 2018 Honda Civic Hatch at HondaPartsNetwork and it says it's only $61.
Intake Manifold

Not sure why this part is stupid cheap. It's likely I'll be ordering this sometime next week. I'll probably send this and a throttle body to Maxbore. May as well get them both all done up and see how it goes. Hoping my throttle body is the same as my old Honda Fit. I think I still have the 2015 Honda Fit stock throttle body in my garage somewhere.

Hondanickx · Jan 23, 2020

Myx said:
Just checked this for my 2018 Honda Civic Hatch at HondaPartsNetwork and it says it's only $61.
Intake Manifold

Not sure why this part is stupid cheap. It's likely I'll be ordering this sometime next week. I'll probably send this and a throttle body to Maxbore. May as well get them both all done up and see how it goes. Hoping my throttle body is the same as my old Honda Fit. I think I still have the 2015 Honda Fit stock throttle body in my garage somewhere.

I thought about that before but after looking at the manifold i don't think there's enough material to port for a larger tb.There's only aprox 3mm up to the seal .

Myx · Jan 23, 2020

Hondanickx said:
I thought about that before but after looking at the manifold i don't think there's enough material to port for a larger tb.There's only aprox 3mm up to the seal .

Then that should work out perfect then. Here's why I say that. I just found my old 2015 Honda Fit throttle body that a fella tried to bore out himself. I purchased it then then wanted to have it professionally done. So I had swapped this in and sent the stock one from the car out so I could continue driving. That homemade bored out throttle body is below. I just took pics of it (found it in garage). When trying to match it up with the Civic's 1.5ltr throttle body in the engine bay, they look very similar. I can't see why they'd be different anyways.

Here's the thread I had documented the before and after pics in of the throttle body (which are all now gone) ~~> HERE
The stock throttle body measurement was:

....Throttle body inlet diameter. It measured at 2.172" (55.18mm)
Throttle body outlet diameter, I came up with 1.966" (49.94mm)
It weighed in at 2 lbs 1.6oz (953g)

After Maxbore did their work
Throttle body inlet diameter. It came out to be 2.33" (59.24mm)
Inlet diameter was increased by .16" (4.06mm)
Throttle body outlet diameter. It came out to be 2.095" (53.21mm)
Outlet diameter was increased by 0.13" (3.27mm)
So I weighed the throttle body. It came out to 2.05lbs (930g).
.05lbs (23g) weight reduction from metal removal.

So some boring can take place. If it is significant....well.....that remains to be seen on this platform. It's at least measurable though.

Honda Civic 10th gen Significant Gains from Manifold Porting Xmas

Honda Civic 10th gen Significant Gains from Manifold Porting Xmas2

Myx · Jan 23, 2020

Gradyjim024 said:
I haven't went and got a custom tune yet so I won't know until then. It should be better at WOT.

Ok..no tune. But have you notice any difference in drivability? Better, worse or haven't noticed anything?

Significant Gains from Manifold Porting

bahndrvr

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Myx

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Myx

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