Lemme know what you guys think. We will be offering this service in the near future if there is enough interest.

here's the lim

is it ported all the way through or just where they mate?

You can't really get all the way inside the uim because of the sharp bends. It narrows alot at the bend and where the runners go into the lim so I think its most important there. I'm going to mess around with it some more and see what I can do though. The lim is done more cause its straighter. If you ceramic coat them, the bead tumbler that they use for cleaning smooths it inside as well so that might help reach into those hard to get to areas.

The more a/f you can squezze in there the better.

Looks like a good idea in my world.

can we get a before picture for a comparison

I'll take some side by side with a stock manifold. I mainly got rid of the rough cast on the inside.

I have done this too. I enlarged them the best I could. I used the flex attachment with my Dremel along with a flapper wheel and went in as far as I could. I think they turned out pretty good for a guy that can't afford to have them extrude honed.

extrude hone is the way to go..

this is after youve matched ported the lim to the intake housings..

roughly, how much would this service cost, if you started offering it?

i was supposed to have mine extrude honed but i ran out of money https://www.nopistons.com/forums/pub...DIR#>/wink.png

$250.

Thats cheaper than buying the cosmo intake componets.

How much bigger are you making the runners?

How much does that run if you don't do it your self?

yep, but still not as big. https://www.nopistons.com/forums/pub...R#>/tongue.png

Bigger isn't always better, but in your application Jspec it probably is.

If you lay the gasket on top of the runners, you can see there is a decent amount of space to open it up. I ported it till the gasket was flush with the edges of the runners. I don't think extrude honing works that well by itself on the fd. Don't hear of anyone doing it. Like I said, If you port them and also get them polished or cerasmic coated, the tumbler they run through to prepare for the process smooths out the inside as well. Poting it can only increase the benefits.

I was always under the impression that intake passages that are really smooth will have a negative effect on performance. It's best to have a somewhat rough surface, because it will churn up the air/fuel mixture slightly, helping it to better atomize the mixture. Like everything else dealing with tuning cars, there's that magical happy medium. Not too rough that it slows down the air/fuel charge considerably, but not smooth as glass that it just slips on through without being properly atomized.



*Shrug* That's basically how I always understood it.

Nope, polished is the way to go. Less turbulance knocking the fuel out.

You're right zen, but you can see the manifold is not really polished inside. Fuel doesn't travel very far in that manifold anyway.