anyone in here perform a port and polish? what are the expected gains on a 3.0? how tough is it?

 

for what it would cost, id doubt the gains would be that beneficial on a naturally aspirated 3.0. as for the difficulty, someone will else will have to chime in.

 

I don't think that you can port and polish a VI manifold. This could be done to a 4th gen, and I believe there are decent gains.

 

i didnt even think about not being able to do it on the composite (plastic) manifold. just out of curiousity does anyone else have an idea if its possible?

 

Wonder if polishing would even be necessary. Since it is a 'plastic' part it is not like it would have rough forging type surfaces. Wonder how much material is really there to 'port' without coming out the other side of certain surfaces.

 

I didn't realize it was a plastic composite.

In any event, unless Nissan made really nice heads, I would think there would be decent gains to be had by smoothing corners on intake and exhaust, as well as mirror finishing the exhaust side.

I was wondering if anyone has actually done this and dyno'ed to get an idea of the gains.

American cars typically gain a lot from P&P work on the heads, but I'm not sure if that is just because they are so bad from the factory.

 

so the 5th gens have a compostie manifold? Is it even worth p & P im trying to gain as much Hp on my maxima but stay naturally aspirated to aviod problems.. any suggestions

 

from what i found p&p on the heads are good gains if you have the right shop do it. other than that the usual upgrades are allways nice gains CAI, Y PIPE, CATBACK EXHAUST, CAMS, ECU UPGRADE, for me i noticed a nice gain from the ypipe an exhaust.

 

Must important thing would be to be sure the ports are aligned or matched and that any obstructions, flashing, casting globs are eliminated. You wanna concentrate on the velocity not boring the hell out of it... or enlarging it,... just cleaning it up some then, roughen it up some to increase the fuel atomization! It will make your throttle extremely crisp and more responsive!

 

I agree. Its not just the size that matters. It's also "port matching" i guess they call it. Making sure everything flows into each other w/o any obstruction.

I definitely know you can port match a '00 VI. Just not the upper composite manifold. The lower manifold, intake ports on the heads, and exhaust ports on the heads can definitely be ported.

BUT, when i removed my LIM, i held the gasket to the intake ports on the heads, there was a very very slight difference in bore size, some if any.

I was going to attempt it, but after seeing that, just decided to delete the swirl valves and call it a day ahah.

 

Earlier engine suffer from poor port alignment but these newly designed engines which are CAD designed have excellent port alignment and fitment. You'll have the remove the heads to get to the real crap!

 

The upper to throttle-body mismatch on '00vi's is absolutely horrible. Just estimating theres 5-10 hp right there, allthough I haven't had the chance to do a before and after dyno, but I will in the future.

 

OMG, i noticed that when i took mine off. It is horrible, and then they stick this metal plate that flows over where my egr hole is suppose to.. like wtf is that all about. That piece of metal made the actual TB bore so dinky. Then came the PF TB