the only reason im asking is because im trying to do everything to squeeze a few more mpg's in.. ive done everything else as far as cleaning/replacing.. this is just a feeler per say to see if anybody HAS done it and to hear the results.. regardless this summer im going to pull the heads and have them ported/polished.
Has anybody had their heads ported/polished?!
- Thread starter jblazy18
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PitbullRescuer
New member
Not on my 4Runner but on other vehicles. For chasing MPG's, I don't think you should go in thinking you're going to have a big return on investment. Not a bad idea if you're already pulling the heads for some other reasons but a ton of work just to try to improve the gas mileage.
JayRolla
New member
I dont have actual results on our motors but Ive been building turbocharged 4 cylinders for over 15 years trying to squeeze as much power out as possible. Over the years of people porting there heads there has always been very little gain. But it also depends on how well the head already flows and I have no idea how well ours does. The issue comes when you start to actually port you need a flow bench to make sure your not hurting performance and once you do go to far you cant go back. Without a huge market of people porting these heads you coudl be gambling.
So a lot of people would just polish it and smooth it out but still very little gains compared to cost and time was not worth it. Not till around 600+whp did we see noticeable gains to make it worth while. Investing in custom cams or something like that would be more worth while but I dont know much about our motors since I just jumped in the 4runner world 2 years back.
JayRolla
New member
I love it! :jump:
aeroneer1
New member
Hahaha nice!
Getting back on topic, I don't think all the work required to port and polish your heads will be worth it for MPG. In fact you could calibrate your O2 sensor with a higher flow motor and get worse gas mileage but a nice HP increase boost! :whipping2
lol.. good one.. i have a very very slow oil leak and i have more oil than what i put in... ie blown head gasket.. so the heads are coming off regardless.. i dont expect a huge gain, and i know without doing a full exhaust too that im not going to see the full benefits.. but.. there are always casting defects in the intake/exhaust ports and gasket matching the ports on the heads definitley wont hurt.. i just wanted to get a feel if anybody has done it... not trying to attempt the fast n furious with this and since these motors are pretty much solid and there isnt allot you can do with them this seems to be a topic that really isnt discussed.. i dont know if its because it really isnt worth it, that these heads are really fine the way they are.. or if people on the forum just dont really like to dip into that kind of modification
JayRolla
New member
All those defects your talking about dont come into effect on a motor at such a low HP. A motor is a very large air pump. At our HP level its not moving much air to make a difference. With the money saved you will be ahead because you wont see a difference in power or fuel economy. Thats coming from someone thats spent money doing it to gain maybe 2-3hp on a 400hp motor.
PitbullRescuer
New member
I agree very much with this. OP, are you planning on doing to port and polish work yourself? If so, I'd be interested to hear what comes of it. But if you're paying for I honestly think you're throwing money away. Not telling you not to do it, it's your call. Just don't think it's cost effective for you.
JayRolla
New member
I agree. If he does it himself he should predyno. The dyno afterwards to see if he helped or hurt performance.
Another thing to think of is if you take to much out you can hurt low RPM power. So during offroading you would lose low end power that you need. And gain high rpm power that we dont need. When was the last time you where in the last 2000prms of the motor during wheeling? Porting usually hurts low end and gives gains on the high end.
my runner will pretty much never see offroading, strictly a to and from vehicle.. and im not concerned about the hp side, im trying to get better mpg.. and yes i know just doing this wont yield me allot.. maybe 1 at most.. but everything adds up.. yea i plan on doing it myself, mr gasket makes a nice kit.. there are different levels of port and polishing, i would just simply taking out the casting defects and like before gasket match the ports, but not taking any material out inside the ports.. polishing the exhaust ports.. the easier my pump intakes air and exhales that spent air, the better..
kman55
New member
98OzarksRunner
New member
Be careful when porting the exhaust side. You don't want to port match the exhaust ports to the gasket. You want the exhaust ports SMALLER than the manifolds/headers and you want a ridge between the port and manifold/header to act as a 'reversion dam'. That keeps pulses in the exhaust from pushing exhaust gas back into the cylinder dilluting the mixture. This is a common mistake amateur porters (and some pros) make, but the best engine builders know not to port match the exhaust side.
Porting is somewhat of a 'black art'. The 'bigger is better' approach usually doesn't apply to porting. Port shape and cross-section matter more than size. And, as noted above, our motors need low-end power (even for a driver) and porting will usually decrease low-end power. Polishing the intake and exhaust bowls will probably make the most difference, and you might get a little power from port matching the intake side. Unless you just want something to do, I wouldn't bother. Porting isn't likely to affect your mileage at all, and if it does it will probably lower it (especially if you port match the exhaust side
: ). If you do it, it would be nice to have pre- and post-port dyno numbers.
Porting is somewhat of a 'black art'. The 'bigger is better' approach usually doesn't apply to porting. Port shape and cross-section matter more than size. And, as noted above, our motors need low-end power (even for a driver) and porting will usually decrease low-end power. Polishing the intake and exhaust bowls will probably make the most difference, and you might get a little power from port matching the intake side. Unless you just want something to do, I wouldn't bother. Porting isn't likely to affect your mileage at all, and if it does it will probably lower it (especially if you port match the exhaust side
: ). If you do it, it would be nice to have pre- and post-port dyno numbers.
steezemcqueen
Moderator
Tune up's and regular maintenance will get you further than porting the heads.
Keep truck running in top shape and have a light foot and you should be able to see in the high teens and low 20's for MPG.
Contrary to what some people think, Toyota did their research when they built this motor.
Keep truck running in top shape and have a light foot and you should be able to see in the high teens and low 20's for MPG.
Contrary to what some people think, Toyota did their research when they built this motor.
twitchee2
Member
you might look into extrusion honing. Ive heard good things about this. ive never done it but my boss suggested it. something to look into
Automotive Performance - Extrude Hone
Automotive Performance - Extrude Hone
