Some interesting ideas from a guy I know
01-09-08, 01:30 PM
#1
Some interesting ideas from a guy I know
Yes, I am basically crossposting this but I would like to know what all would be the pros/cons of porting all 4 ports on a 12A the same size. I am thinking for the most part the low end would suck but the high end may be considerably better... What do you guys think?
Hi AGAIN guys.
Some questions will seem stupid, others will be stupid. Please keep reading.
The setup Im going for
12a
RB porting templates
13b-rew intake manifold and TB with an adapter
Megasquirt ECU
Staged injection
Please keep in mind I´ve got separate intakes for primary and secondary ports
Im going with a "mirror" finish from the TB to the injectors, then, a more rough one, for turbulance and atomization purpose.
Will try to route all vacuum signals to the primary intake runner.
IF I go with the same size of port on all 4 ports ... what kind of idle will I get?
Will my idle be more affected by exhaust port than intake port?
How much will performance suffer if I only port the secondary ports?
I already have a turbo car with a clutch from hell, and Im trying to get a decent power for my "semi-daily" driver 7.
All input is welcome. I´ve been reading A LOT here and over at nopistons... but I still have this questions. I wasnt unable to read something like "I did that and my car idles at 750" or "I did that and got XXXwhp"
Some questions will seem stupid, others will be stupid. Please keep reading.
The setup Im going for
12a
RB porting templates
13b-rew intake manifold and TB with an adapter
Megasquirt ECU
Staged injection
Please keep in mind I´ve got separate intakes for primary and secondary ports
Im going with a "mirror" finish from the TB to the injectors, then, a more rough one, for turbulance and atomization purpose.
Will try to route all vacuum signals to the primary intake runner.
IF I go with the same size of port on all 4 ports ... what kind of idle will I get?
Will my idle be more affected by exhaust port than intake port?
How much will performance suffer if I only port the secondary ports?
I already have a turbo car with a clutch from hell, and Im trying to get a decent power for my "semi-daily" driver 7.
All input is welcome. I´ve been reading A LOT here and over at nopistons... but I still have this questions. I wasnt unable to read something like "I did that and my car idles at 750" or "I did that and got XXXwhp"
01-09-08, 02:59 PM
#3
it will totally depend on how large of a port your end result is and just how sensitive your driving style is the loss on the low end. in most cases you can tune some low end back in, but if the template you're using is just THAT large, then you might want to port the primaries to be a little more civil.
01-09-08, 04:03 PM
#4
Sounds like a plan then to go with smaller primaries. Is it ok to polish the intake manifold runners as good as the port/runners on the irons? Get rid of casting marks and then use the coarse sanding rolls, then finish off with a 220 grit scratch for the polish?
Also a mirror finish is OK on the exhaust right?
Also a mirror finish is OK on the exhaust right?
01-11-08, 12:49 AM
#6
Back at it again!!
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Correct. Best to polish the exhaust ports as smooth as possible (mirror shine), and if you're running a turbo, then you can do it to your turbo exhaust manifold as well. And if you're REALLY ambitious, you can do the exhaust turbine housing in the turbo too!!
Intake is quite the opposite.
I use 80 grit
Intake is quite the opposite.
I use 80 grit
01-11-08, 10:23 AM
#7
Correct to all of the above. Mirror is fine on the exhaust but not the intake. This is why I'm not a fan of extrude honing. It's a great way to make a runner slightly larger and get the flaws out but it's too smooth. If you were to get it extrude honed and then run a sand blaster through the manifold, this would be a nice finish. It would also be costly.
I've found 80 grit to actually be fairly smooth if you are gentle. There isn't much need to go too much higher above it. I know Mazdatrix goes up to 220 or so in their ports and they also say the same thing about a mirror finish. Where you choose in here is your choice. I wouldn't go above 220 though. That's plenty. Remember that even if 80 grit is too rough to be optimal, it's still a huge improvement over the stock casting marks.
I've found 80 grit to actually be fairly smooth if you are gentle. There isn't much need to go too much higher above it. I know Mazdatrix goes up to 220 or so in their ports and they also say the same thing about a mirror finish. Where you choose in here is your choice. I wouldn't go above 220 though. That's plenty. Remember that even if 80 grit is too rough to be optimal, it's still a huge improvement over the stock casting marks.
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