slammed

iTrader: (8)

Newbie Question


Wondering how much HP/TQ would I gain with port and polishing my engine.

Also, what is the price range of what Im looking to spend?


another thing, I have not seen a .org member with this upgrade....why is that?


thanks in advance

XeroX

iTrader: (13)

im not sure but i think this is in the faq

I30tMikeD

iTrader: (8)

What in the hell is porting and polishing your engine? You sure you know what your talking about? Explain to me the process....

Pimpmobile

iTrader: (1)

IIRC prices range from $1000-2000 and the gains are not worth it with our heads.

PLkiller

too much time on playing Need For Speed...welcome to the real world

slammed

iTrader: (8)

wow!! thanks man


I guess it wasnt a newbie question after all


Port and Polishing frees up the factory debris inside the head on both the intake and exhaust side

mechanics machine the bottom of the head to make sure it is flat, then they measure the combustion chambers to make sure they are all the same (equal pressure on all cylinders)

They take die grinders and free up the air flow in and out of the head creating better flow and increased throttle response as well as power gains

slammed

iTrader: (8)

silly boy

I30tMikeD

iTrader: (8)

You your talking about porting and polishing the heads....

slammed

iTrader: (8)

yes sir

Jeff92se

iTrader: (82)

You still don't know what the hell you are talking about. Where did you copy/paste this information from?
1) How do you know there is any "factory debris" haha inside the head to be freed up?
2) You don't "free up" airflow. How do you know making the ports larger and/or polished will do anything for power? Just porting them DOES NOT mean better for performance.

You need to read some more IMHO

slammed

iTrader: (8)

k


im learning....as everyone does


thanks

tomservo291

port and polish is not just a video game joke, there are many cars in which this makes a huge difference... if the OEM was junk and not manufactured well or just not designed well from the get go it can help immensley.

I also believe it's very good if you go FI as it helps in all aspects to getting better flow through the engine...

it may not be worth it to the VQ without a SC/turbo but it's not a dumb question

I30tMikeD

iTrader: (8)

No, but asking about porting and polishing your engine is

NISMOPower

iTrader: (2)

Well if he never asks then he would never know would he. He just learned a little extra. Members always post insulting everyone else and that makes others feel stupid and don't want to post. Just let the guy know what it is or let him give him a guideline for it. Or just let him know that it's not worth it, unless your FI like tomservo291 had said. If you think he is stupid for asking a question even if it's the most idiotic most common sense question, just don't post...Does anyone else agree with my opinion?

dayglo

i think he put up with u snapping at him pretty well..

i looked it up and all i could find as far as info is exactly what he said.. whatever though its expensive buy something else thats more guaranteed

Maxtank

iTrader: (8)

the VQ is finished vis micro polishing.......port/polish is not worth it

zazon

iTrader: (4)

ya i would much rather ask a dumb question on a forum than go into a machine shop and get laughed out or something, but yeah people are definately a little harsh sometimes

2 Da Max

iTrader: (2)

speaking of port and polish what about msd?? do they have msd ignition for coilpacks?

JSutter

iTrader: (46)

the ports on our heads are very very smooth already. there may be some gains to be had with shaping around the valve guides but in my mine its totally not worth it. Matt (mardigasmax) has done a DIY port job. Not sure on the details.

On a side note you can over port them. They could flow like crazy on the flow bench but may not work well with the choice of cams. Take the 4G63 and SR20 motors. They can both use some work but they can be ruined quite easy. Only experianced mechine shops know what they are doing.

sterlingmaxima

iTrader: (16)

my friend did it on his camaro him self it worked out great but his dad showed him how to do it it is not that hard on a 350 motor but a vq might be more complicated and more difficult.

1200 for a port and plosh job seems outrages to me there has to be cheaper places.

the hassel of taking your motor out and putting it back is probbaly not worth the 20 horses if that for this mod.

2 Da Max

iTrader: (2)

yea port and polish jobs go for around 600 -800 dollars at the shop over here

slammed

iTrader: (8)

thanks man


I dont understand why some people in this forum are like this


everyone here was a newb once....

everyone here asked a "dumb" question....


this is what helps out members....Q&A

slammed

iTrader: (8)

Thats all I could find on the subject

sterlingmaxima

iTrader: (16)

of course that is all you found that is exactly what it is. You described it perfect and on another note there is always gonna be debri in the engine I dont care what engine
engine's are always gonna have metal to metal friction some were in the engine causing shavings to be present in the motor.

SMX95

iTrader: (8)

Only works pretty well for V8's. They can upgrade to a **** load of things, roller rocker arms, solid lifters, ported heads, racing valve springs ect ect.. We have twin over head cams, not much that port and polish would do. Our stock headers have great exhaust flow, and the intake ports are pretty good to begin with..

japmaxSE

iTrader: (7)

Well I did my heads at a machine shop and when I compared them side by side huge difference in size you can see how bigger they were than stock and I also did the Lower IM to match. I wish I had took pics cause even at the shop the other guys say that it should give gains not sure how much but I don't really care I just know my heads have bigger intake ports than stock and there polished nice and smooth. for me it's more for just the heck of it it was free done all on my own.

JSutter

iTrader: (46)

A typical domestic V8 has 16 valves, 1 intake and 1 exhust for each cylender. Now we have 24 valves which makes the cost increase quite a bit. Also people usually get valve jobs at the same time and then there is even more money. The gains dont justify the cost unless you are building a full race motor.


bigger is not always better

JClaw

iTrader: (17)

I heard there is a risk of making 'em worse. Heads are not the place to look for power on these engines it seems. Intake manifold is a much better place to look for extra power...

VQ30GTR

Make them too big and you reduce the velocity of the air coming in (assuming N/A) and it can stall at idle. It is like trying to move a column of air through a 55 gallon drum vs. a straw. it will move through the straw, most likely not through a 2 foot hole with any velocity. Like the guys in the rustangs that sit at the track and the car dies every min. or so, those are ported for top end flow. But if done properly you can increase the performance of the engine. You need someone who has done it and knows how large to go. So it is not a cosmetic polish job like Nissan did. You port the heads, assuming you have a flow bech so they are all equal and then polish. Actually I believe they swirl the surface to create turbulence in the air flow, aids atomization. And no I do not think there are many people on the .org who have done this. So his question is a well founded one.

IceY2K1

iTrader: (3)

DOOOOOOooooo it...just make sure you get before and after dynos.

Hey, it's your money and we won't know until people try.

Duckman540i

iTrader: (12)

There is alot to know about Port & Polishing you should know before taking it to an amateur for porting. An amateur can "Hog Out" the ports, making them too big. (Bigger is not always better) Big ports can flow big numbers, but big flow numbers alone will not make big HP. Larger Ports have a lower flow velocity given the same flow demand. An air column of a given mass at a lower velocity has less inertia, and less potential energy, possibly killing any intake ram charging effect. This is why alot of "Too Big" Port jobs make cars die at low RPM's. Also weakening the block. It it also important to have a good balance for high RPM Volumetric Efficiency. Over-ported heads will have Boggy low-end power, And/Or more HP (only) in a narrow peaky high RPM range. Also the delights of a rough, lumpy idle. The best way to port a head is to get the best shape to get maximum flow, with the minimal amount of enlargement. Velocity also should be the main priority. A good head porter/polisher will spend many hours on a flow bench, to get the best results. I'm really tired, So I'll finish off with a good Theology. (Picture sucking a milkshake through a small straw. This takes alot of sucking effort.............Now drink the same milkshake through a larger straw; it's now much easier huh? The main trick to "GOOD" head porting is making the "Straw" big enough to feed your thirst, but not so big that you can't suck hard enough to get the milkshake to your mouth!) Also some people should be more nice when someone asks a simple question like that, & just reply with a usefull & helpful answer. I once asked the same question, but now after years of studying & much more knowledge of cars I know. So it really wasn't that bad a question. So lets all just help each other out & not be negative. Thanks

jdmmax

iTrader: (6)

here some pics of a set off heads i have sitting in my garage.


exuast ports


intake ports

intake side pics of the swirls


bottom of the head

not sure what the gains will be. i will begin building a motor later on this year after a few toys come in. like vq30GTr said the intake ports have been swirled.
the heads may be usless though cause i got them without the the came towers closet to the came sprockets. and these parts cannot be purchased seperate from a set of heads. and advice or opinions eads are welcome.

4thgenx42

Hey do the job if you want to. Dont listen to this moron making you sound like you dont know what you are talking about. People we arent here to bash each other, were here to learn from each other. Port And Polish is a process that has been used for many years. If this I30 moron has never heard of this then i suggest to read up on performance cars more often

BlackBIRDVQ

iTrader: (15)

4thgenx42 I suggest you STFU about I30tMike, he unlike you turbocharged his *I30t 5spd* and owns one of the rarest Nissan breads of all. He does his own work etc.

I did my own pocket porting on my SR head and little bit of gasket/port matching on the exhaust side and intake side of the head, it didn't loose any power at all and actually gained a few ponies down low 4WHP with max gain of 11WHP at 8K RPM. I aint saying anyone can do it but if you have access to bench flowing machine and can find out your heads flowing capabilities before and after you COULD build a awesome head. Dan Paramore Racing builds one of the best cylinder heads in the bussniess, some of his Honda heads where 40-60WHP gains at the wheels on full race motors. Honda heads are pretty high flowing compared to likes of lets say 4G63 so gains are not as big, but he still manages to find alot of power in the B series heads. Be prepared to spend bout 3K dollars with him if you want awesome heads.

BlackBIRDVQ

iTrader: (15)

jdmmax- you can take the head to a machine shop and have them LINE bore the cam towers so that everything is in PERFECT aligment- after you get all the cam caps. Most professional cylinder head places will line bore the rocker shaft bore (on Honda VTEC DOHCs) and cam towers for perfect aligment. It shouldn't cost you alot of $$$. I really like what you did with the heads, good work !

95BLKMAX

iTrader: (10)

jdmmax, what was the reason they told you that the intake ports should be swirled? I'd assume it has something to do with creating for a better mixture, however, how much more effective is the swirl finish over a polished finish on the intake ports?

I know you guys are speaking of heads, but I just felt like throwing this in here sincee it is somewhat relevant
;
I did a port and polish job on my lower intake manifold, used the gasket to portmatch the lower to the upper, and port and polished as much as I could reach into the runners of the upper IM. Then I used the gasket to portmatch and P&P the IM and TB. The heads were not touched as I dont have the time to remove the heads.

Although I have no before and after dynos of this, me, Nismology, streetzlegendz, and s0ber can assert to an improvement on midrange power and upperend breatheability. It was not ported significantly, so bottomend power saw no loss at all (at least from my butt-dyno). When I get home from work I'll put up pictures of the work.

Now to get back on topic a little, if I were to do a P&P on the heads myself, I'd only do enough porting to match the port on the intake/exhaust gaskets on either side of the heads, so as not to increase the changes of messing up the flow characteristics. However, I would polish the entire runner surface. I know some of you guys were saying that the heads' runners are already smooth. I felt the ports before reinstalling the lower IM, and compared to the polish I did to the LIM they're rough! So yes one should see some gains from doing a P&P on the heads. Wheather or not it would be worth the work is up to you... Gotta love the dremel

jdmmax

iTrader: (6)

im not to sure what the swirled surface is for i just know what others have told me about it. several people mentioned to me that lisa kubo use to run swirl intake port/polished exuast port on here eg drag car. i don't know to much about p&p heads.
i did not accually have the heads worked on myself. i got them in trade at a friends performance shop. the heads were ported by a local shop ported honda,mitsubishi,mustang heads. Premier autoworks use to send out all ther cylheads to this guy. i am trying to get different opinions on the head. im gonna take it to a mechine shop and get a opinion including a few other engine builders DPR will be one of them.

95BLKMAX

iTrader: (10)

Soory for the delay, here they are:


That's how it started out. All the runners looked black like that and were rough


That's the porting and somewhat polished. I went at it afterwards with a sanding bit and that left it like silk.



That's how I got to it on the underside.



That's the finished product. And I weas only about 1/2 way done with the actualy polishing when my "cameraman" had to leave.

Hope that gives you an idea of what I did.