I have an 00 civic with a d16y8 in it...i/h/e.

I recently got a spare y8 mani in a batch of parts I bought for really cheap, included in this was a GSR TB. I planned on porting the intake to match the tb...polishing up the outside for looks because I have some spare time...and a spare intake mani so why not?

The big issue is that I've done alot of research and hear so many mixed things about polishing the runners...and if this a good idea or a bad idea. It seems all of this is opinionated off of he said she said. The big arguement was that it needs an imperfect surface to create better fuel atomization. Unsure if they were confusing intake side of the head with the intake runners...because that doesn't make sense to me. I've done a good bit of research and all the replies seem to be confusing and counter-productive.

Can anybody clarify if polishing the runners would be a good idea? What would be the best way to do this? Would it even be the slightest bit advantageous? As I said I have spare time, and spare parts so unless it really really really isn't worth it please avoid saying it's not worth the time.

Thanks in advance.

 

sorry, there is just way to much "tech" in that question... haha.

although i don't have a direct, first hand answer for you i've come across info here and there in the course of other research that may help you. if you haven't yet check out the members and threads over at 'one cam only' (Google it..). they carry a heap of scientific credibility and helpful, useful info. theoldone.com may have a few useful articles or archives, i think also team-integra.net has some good tech articles.

i do think i'll speculate some though.. i can't imagine a "polished" surface would be any better than an even but coarse surface. i think what would benefit (if anything at all) would be to clean up the casting lines and give everything an even texture with sanding rolls or the flapper deals.

And i agree, the 'atomization' argument is just kids repeating what they heard elsewhere.. even though it doesn't apply.

 

This reminds me of an article I read in Super Street back in the day concerning a process called extrude honing where they pretty much used certain materials to polish the interior surfaces in order to reduce friction and resistance.

I don't know if this was the company but they are the top 4 search results on Google.
http://www.extrudehone.com/auto/auto-performance.php

Sounds like a sound practice to me.

 

If you're doing this with the goal of turbo'ing eventually it's a good idea. BIG tb and ported manifold will greatly increase flow.

On your naturally aspirated d-series you'll see a pretty minor but noticeable increase in throttle response.

If you browse the all motor forum people polish the runners of intake manifolds all the time.

 

Thanks alot for all the info! I'll have to check out all those links and run down some methods and stuff.....kinda like the whole measure twice cut once theory....I want to know as much as I can before I start hacking into stuff.

I plan on boosting...I was going to do it for tax season but I had some recent body damage...and planned to paint so I'll be fixing the body damage and painting the EJ8 white so that will consume a good bit of my extra money. Since I have the intake and TB I figured I'd start now since it's stuff I can do at the apartment.

It's not hard to do it when you have the extra parts as well...I've seen everything from port-matching...to knife-edging the TB plate...minimal gains to be expected but if I get bored I might do it.

 

ive also read before u dont want ur intake side of a head completely smooth and polished you want it to be alil rough to fuel can deposit on the walls and evaporate quickly.flow testing a mirror finish vs a texture surface the flow is only about 1%. exhaust ports can be mirror polished. this is for heads but im sure could be useful when porting an intake manifold. lil info about porting n polishing here.... http://en.wikipedia.org/wiki/Cylinder_head_porting

 

I think this is been the most resourceful set of replies I've gotten on here in awhile...keep 'em coming...

Tonight I'm going to get the dremel out and knock some of the webbing out between the runners...smooth out some of the heavier cast marks and whatnot. Gotta get a new TB gasket before I start the port-matching.

 

i like the lack of knowledge here

 

Care to add some then?

 

let me break it down 1 the y8 intake manifold casting inside is terrible the design is crappy.. PROVEN 2010 THIS AINT 04 KIDS RESEARCH!!!!!!!!!!!!!! stop asking questions ONE CAM ONLY FTW ACTUAL PEOPLE WHO RESEARCH AND DEVELOP (SOHC FTW)


- the angle of plenum to runner merge is very sharp which causes more velocity but also more turbulence.
- the runner lengths them selves are unequal aswell as inside diameter so runner 1/2/3/4 flow differently causing combustion to differ inside the motor.
- polishing the intake would only mess with air flow (fuel atomization is best with rougher casting) IE: the exhause should only be polished for velocity and heat retention.
- extrude hone is pretty much opening (port matching the beginning of the plenum to accommodate for larger TB
- if you were to port your y8 mani figure out if you are going ALL MOTOR or TURBO so you can port match to head or keep the step for anti reversion
- theres only soo much you can do with stock parts the ammout of casting you need to take off to make the intake flow better is a lot so its better to get a EDELBROCK performer X.
- COST (welding) (porting tools)+ TIME (labor)= NOT WORTH IT my ported mani still got outflowed by my cheap blox LOL.
- the more air you put into your motor the leaner your car will be
- if you look at the runners them selves they are close together and also the diameter is small so if you were to cut that manifold apart those edges and grooves would be hard to grind down. angles of the runners are weird IMO.

 

Thank you for the knowledge. I'm not looking to do anything major...clean up the outside by getting rid of cast marks...taking out the webbing between the runners...and getting it to as high of a polished finish as I can. I'm definitely going to port match for the TB...and I was just curious about the runners...it wouldn't be anything major...just smoothing them out a little bit.

I'm not going to pay for a new mani...this is a project for fun...looks...to fill up time...and if I can get a little performance out of it, cool.

I bought a y8 head, intake mani, gsr tb, and knock sensor for 60 dollars. It's a spare...so either I make use of it...have some fun...make the bay look a little better...maybe get a little better throttle response and flow...or just toss it in the corner.

Don't knock on the y8 mani so much...compared to other OEM intakes it's pretty decent.

Thanks for the input on all the other stuff though.

 

just let me know how it goes. use a flapper wheel -and dont use stones ( or bits used for wood they clog easily) faster = smoother >< slower = rougher i did fast with corser grit then slower with softer grit

 

Would it hurt to go a little bit bigger when port-matching the tb...like 1 mm farther?...or should it be an attempt for an exact mate-up.

 

if you go 1mm over it wont hurt but its recommended to not port match TB to plenum when you go turbo you need that "step" for anti reversion look it up if you dont understand

 

^ Go figure I looked up anti-reversion and found alot of answer concerning port-matching.

https://honda-tech.com/forums/acura-integra-6/throttle-body-boring-intake-manifold-port-matching-1890101/

Here is a good read if any of you get the time involving port-matching, anti-reversion and a fun little diy.

Now my issue is going to be the air injection on my 00 y8...it's not included on the 98...and I have to figure out if I plug it off on the hose side if it will have a problem...all I can find is people putting the 99-00 manis on 96-98 not the other way around...if anyone knows chime in...if not I suppose I'll make another thread.

 

good read, kinda wanna try my hand at some minor port work now.

 

^Definitely.

There's so much conflicting information online...previous thoughts on anti-reversion only seemed to be on the exhaust side...now I'm seeing it on the intake side of things and I guess I'll have to keep researching just a little longer to see how it will work before I go porting the intake side.

I did some basic work with the dremel today removing some of the webbing and cast marks on the outside.

This whole polishing the runners affecting fuel atomization still doesn't make sense to me...the injectors push fuel almost directly into the head...so it makes sense that polishing and deburring the runners would only help air flow and atomization issues would occur in the head...which I'm not going to touch myself.

 

that was ment for heads but it shows that you dont need to mirror finish it just get it smooth. the flow difference isnt enough to affect much at all.

 

coarser grooves = more turbulance thats all that why i said clean up or smooth out by changing speeds and using a different grit. but polishing the intake will mess with air flow. as for air injection i just covered holes with jb weld. if you see articles look up dates and who wrote the article... TRUST ( ONE CAM ONLY, D-SERIES.ORG, TURBO D16.COM, REAL HOME MADE TURBO. COM )

 

Fuel atomization i couldnt really explain why you shouldnt polish it but ill try. fuel atomization is when the fuel (liquid) is "misted"/sprayed out from fuel inejector if you notice the injector it pulses or sprayed out mist of fuel not a stream. so by polishing the runners the fuel does not "mist" causing bad fuel atomization meaning the fuel doesnt burn properly causing. rich burn/ possibly fouling out spark plugs and also washing rings (after a while) not instantly. so by not polishing it will retain good fuel atomization. if you see aftermarket injectors they usualy have more than 1 pin holes that spray out fuel not one.. so that is also part of the theory behind why its not good. ( it usually only counts with head but not sure about intake manifold) but look it up. Polishing the manifold might actually help air velocity