Intake mani porting...too much for a newb?

[Calgary280ZT]

I searched and read many posts about porting the intake manifold. I'm not a very technical guy, so a lot of it is over my head. What I want to know is, should I take a crack at porting my manifold or leave it to the experts?

 

Have a brand new P90 Rebello head, which flows as follows: 1) intake at 25 psi, 209; 2) exhaust at 25 psi, 150. Head has larger SS valves and mild turbo cam. I have a new T3/T4 turbo. Will be installing Megasquirt. Hope to make 350 rwhp.

 

From the posts I read, there is power to be had by porting the intake manifold. I can pick up a spare P90 head to work on, in case I bugger up something at least I'd have a spare. If it's relatively simple, I'd like to at least try doing the porting myself. But if this car has taught me anything it's to recognize my limitations.

 

Opinions appreciated. Do it myself or leave it to the experts?

 

Mark

[mario_82_ZXT]

I can pick up a spare P90 head to work on, in case I bugger up something at least I'd have a spare.

 

I don't understand this, I thought your head was already ported?

 

The problem with the intake manifold is the runner diameter. From what I understand, there really isn't enough "meat" left on it to be able to do any suitable amount of porting. I would go with a custom intake manifold from one of the many custom intake manufactures, or design and weld your own.

 

Mario

[Calgary280ZT]

Mario...DOH!! Yes, head is already ported, I meant the intake manifold. Interesting commment on not enough meat left in the runners...I see Lonewolf offers a ported manifold, wouldn't they have run into the same problem?

 

I agree a custom manifold would be best. I've already overspent this year's budget on head, turbo etc., so that will be tough. Thought I could save a few bucks by porting the mani myself. Your idea of fabbing my own mani is interesting. Would have to learn how to weld again...last time was in shop class...and that was decades ago (don't ask how many!!).

[2126]

Maybe a call to Dave Rebello might shead some light on the matter!

[Calgary280ZT]

2126, funny you should mention that, I almost picked up the phone this morning. But I felt funny picking the guy's brain about a service that he offers himself. And from what I've seen on this site, there are a number of guys who are pretty knowledgeable about porting intake manifolds.

 

However, if Mario is correct and there isn't enough meat on the runners to do a good port job, then maybe I'll just have to look at a custom intake. The only reason I thought about doing it myself in the first place was I saw Lonewolf offered ported Nissan manifolds. I thought, if they can do it, maybe I can do it too. Probably not as good, but good enough until I can afford something better. But from the posts I read it seems that porting is not that easy, there's some theory involved and a bad port may be worse than no port. That's why I posted here. Wanted some advice from guys who have done it, maybe I would be biting off more than I can chew.

[OlderThanMe]

Check out extrude hone:

http://www.extrudehone.com/afmpro.html

I think several people have done exhaust manifolds with them but you can probably get an intake done too.

[Calgary280ZT]

Dan, thanks for the link, looks like they charge around $700 for the intake and $625 for the exhaust. A little too much for this year's budget, I'm afraid. Lone Wolf looks to be around $325 for the intake. I'd still like to tackle this one myself...time for more research!!

[OlderThanMe]

DANG!

Yeah I guess DIY is definitely the way to go. LOL

 

A custom intake would cost less than that...

[Dragonfly]

This could be a worthwhile investment for you http://www.themotorbookstore.com/scdeofexinsy.html it will go a long way toward your goal of DIY.

 

Dragonfly

[mario_82_ZXT]

I think JeffP is running an extrude honed intake.

 

Best bang for the buck right now I think is Lonewolf's intakes. Last I checked they were one of the cheapest out there and would be built to your specs.

 

I'll looking into porting the stock one, but I'm almost 95% sure that you can't get much out of it.

 

Mario

[Calgary280ZT]

Mario, just curious, why do you think you can't get much out of the stock manifold? Not much gain to be had? Need specialized tools? I emailed Lonewolf today and asked for the flow #s on their honed stock manifold and custom manifold. Will post if I get the info.

[JMortensen]

I haven't ported an EFI manifold, but just looking at one I think it would be very difficult to port the plenum side of the runners. Presumably the way around this issue is to cut the plenum off, port the runners with access to both ends, then weld the plenum back on. For all the hassle, a $325 manifold that is known to be an improvement would be a much easier solution. I haven't seen any testing on Lonewolf's intake, but I wouldn't expect it to be hard to improve on the factory intake. As always, if you have the tools and the desire to port the stock piece, go for it.

 

Extrude hone is done by forcing an abrasive through the manifold. It will clean up rough casting areas, but won't make the ports substantially larger and can't really be controlled to match port size to the gasket or to shape the port in a particular way. I suppose if you wanted the super port and polish, one could port the heads in the traditional way and then extrude hone it. That would give the right shape and a super smooth finish.

 

Here is a short and to the point critique of extrude honing:

http://www.tmossporting.com/tabid/3717/Default.aspx

[Careless]

I always thought it would be effective for getting the exhaust side nice and smooth AFTER it's been handled by a human being or a cnc machine. All it does it enlarger or smooth the ports, depending on the grit. What good is that if you're trying to maintain velocity anyway?

 

I think it only makes sense on the exhaust side, to get it nice and shiney.

[Calgary280ZT]

Jon, thanks for the great info on Extrude Hone, clearly not an option...I try to avoid the "inferior results for premium cost" kind of modifications!! LOL If I hear from Lone Wolf I will post their flow numbers. You're right, $350 is pretty cheap given the difficulty of the job....but I want to see some numbers before I pony up the bucks.

 

Careless, sounds like any DYI porting should be on the exhaust side...which I now need to research, since I know absolutely the square root of squat on the subject.

[primer&rust]

I have ported my intake some advice I would give is to get a ready long mandrel for your cartridge rolls so you can finish the whole runner.

[Calgary280ZT]

Primer&Rust, how long did it take you to do the port job? Were you able to get the entire runner or just the part your tool could reach? Were you able to test it on a flow bench? Thanks for posting the pic. Mark

[OlderThanMe]

If you are going to just port match the intake to the head, then make the transition as long as you possibly can into the runners.

 

The stock intake seems to start being a restriction at around 400hp.

On a 350hp engine a simple port matching should be fine. I don't think I'd worry too much about hogging out the whole intake.

 

As Mario stated, JeffP is using a highly modified stock intake and he is making lots of power.

Porting/port matching to a gasket article:

http://www.allpar.com/fix/holler/porting.html

This can also apply to an intake manifold but in reverse for matching to a gasket.

 

read ALL of BRAAP's posts...

http://forums.hybridz.org/showthread.php?t=108398

 

I sugest you check your intake gasket against your Rebello head and see what overlap there is on the intake runners. Then check against your intake manifold for the same thing. Ideally your intake gasket would line up perfectly with the intake runners on the head and on the intake when torqued together.

I'd like to get an endoscope-type camera with a flexible head on it to look down inside of intakes and exhausts to see how the gaskets overlap when torqued down. (and for other diagnostic car things...)

A while ago BRAAP posted about an intake/exhaust gasket for an L6 that had a metal contact surface around the intake and exhaust ports. I think they are NLA though.

Dan

[Tony D]

As Mario stated, JeffP is using a highly modified stock intake and he is making lots of power.

 

That's a bit overcooking the statement. Mario said he extrude honed the manifold. That is correct. He extrude honed it.

 

It is not 'highly modified' unless you consider the stock AAR and EGR being blocked off with shiny plates.

 

The Extrude-Hone price is retail. If you show up in Paramount and talk with the guys you can get it done for half that price (same advice I gave JeffP, and why he did it).

 

For the Turbine Housing it's a nice finish, it gets casting flash out of the thing that you can't get to any other way. Diesel Places routinely do it because they find they can pick up 2-3%.

 

In any case, Extrude Honing is going to cost money and take time. A home port with some cartridge rolls is probably your best bet. You can pick up all the stuff you need at McFadden Dale Hardware in Corona or Anaheim (very close to the MSA Events when you are down here).

 

What I found nice for doing the quickest cleanup is appropriately sized flapper wheels on a long mandrel. It makes nice work of cleaning up the runnners, rather than enlarging them. I'd remove the bumps at the injector end from the hold-down bolts (use sealer on the bolts for S&G) and then concentrate on simply smoothing the runners of all casting flash.

 

With a long mandrel, you will be able to get a flapper wheel in from the back side (Head End) all the way to the plenum. The hardest thing to do is remove the damnable EGR bumps at the inlet of the runner on the plenum end. I have seen N/A plenums where people have used hole saws to cut access holes into the plenum and get to the inlet end of the runners. They then epoxy/weld the plugs back in, or use core plugs to seal it back up. No real need to cut the whole plenum off to access the runners.

 

But given the size of the runners will be likely quite a bit smaller than the ports Dave gave you, I would say concentrate on smoothing the walls more than trying to enlarge them, and use the 'step' at the head as an anti-reversion measure for anything that may happen during valve overlap events. It's a big step, and should be closer to 1mm, but if you try to enlarge those runners you're going to be in for a miserable time trying to get it right without cutting up the plenum. I don't think you can do it without cutting the plenum in some way...hence my concentration on simple smoothing and removing the bolt bumps that impede flow.

[primer&rust]

I think it may have taken about an hour to port the manifold. I only got about half way down the runner because my mandrel was not long enough. I used the standard abrasive deluxe kit summit racing sold for $50 at that time. I still have some cartridge rolls left from it and I have ported a supercharger, 2 intake manifolds, and 2 cylinder heads even though one of them was a light job on a 4 cyl. I did not flow test the job, just a DIY project but my car with the ported head and manifold runs very good. Use WD 40 for lubing the cartridge rolls and a die grinder with good air pressure. The porting kit comes with instructions for porting cylinder heads. Porting the intake all the way could be a little tricky because after you get so far down the runner you can't see way you are doing. I also opened up the throttle opening pictured above.

[MONZTER]

If you know someone who can weld aluminum, cut it open and go to town. It is really easy to clean them up once you can get inside.