Who has the best ported exhaust manifold

[roachjuice]

So. Who's is the best? Any back to back runs with a stocker vs a ported? Vendor or non vendor. Post up. I'm looking to buy one. Just want the best.

[tryingbe]

I ported mine, and you know how quickly my turbo spool.

[roachjuice]

You did it your self? What did you use? I has a compressor. I think I may have some of my old machining tools laying around too.

[roachjuice]

This is gonna be a 2.5 and stock garrett setup.

[Ondonti]

What happened to that guy obsessed with his own exhaust manifold port jobs?

[BadAssPerformance]

I ported mine,

You did it your self?

Sounds like he did... For a basic port job, its not to hard to open things up. Cast iron is easy to work with and remove material. A nice bit (carbide is best, but grinding stones work too) on a drill or die grinder can do wonders. Just gotta be sure to be very carefull to have each port balanced as much as possible and when you tackle the bottle neck between #3 and the collector not to get too greedy and bust through.

What happened to that guy obsessed with his own exhaust manifold port jobs?

Have not seen Mr. Ported Stocker on in a while. I have to say, I did see one of his exhaust manifolds in person and it did look like a nice port job.

[4 l-bodies]

What happened to that guy obsessed with his own exhaust manifold port jobs?

You must be thinking of moparzrule on this forum. Matt is his name.

[4 l-bodies]

Sounds like he did... For a basic port job, its not to hard to open things up. Cast iron is easy to work with and remove material. A nice bit (carbide is best, but grinding stones work too) on a drill or die grinder can do wonders. Just gotta be sure to be very carefull to have each port balanced as much as possible and when you tackle the bottle neck between #3 and the collector not to get too greedy and bust through.



Have not seen Mr. Ported Stocker on in a while. I have to say, I did see one of his exhaust manifolds in person and it did look like a nice port job.

#2 runner is the worst flowing. Can't do a whole bunch with it without cutting it open and welding in material. You port heavily and get #1-3-4 to way outflow poor ole #2. Then you have the crappy balancing your talking about JT.

I've ported a lot of exhaust manifolds. I will now only do them when I build complete motors. Same with baffled oil pans. IMO, too much labor for what you can sell them for. I have about 6 hours in one from start to finish. IMO, you sort of get what you pay for when it comes to ported exhaust manifolds. Has the the manifold been beadblasted with aluminum oxide and coatings applied? Are both ends resurfaced? Studs removed and threads chased? Any cracks? All good questions to ask when looking for a exhaust manifold.
Todd

[roachjuice]

Rob M is gonna do one for me.

[Ondonti]

There was a thread about getting the most balanced ported stocker but in the end I really don't think flowbenching an exhaust manifold tells you much about real world results that you can't figure out by looking. Its still a log manifold in the end. Backpressure will still be king.

[Directconnection]

#2 runner is the worst flowing. Can't do a whole bunch with it without cutting it open and welding in material. You port heavily and get #1-3-4 to way outflow poor ole #2. Then you have the crappy balancing your talking about JT.

Hey Todd, you know I totally respect the stuff you build. Always top notch! But I have to disagree with you mentioning #2 as being the worse flowing, when in fact... it's flows right up there with runner #1 as they are almost direct straight shots into the collector. (with probably some interference from the log flow of #3 and #4)

{EDIT: I messed up as I had it backwards in my mind... late night... I did know it was #2 though, as noted in my flowbench thread posted below from years back... hehehe}

Here is an EXHAUSTING (hehe) flowbench comparison of many ported stockers and log headers that I flowbench on my flowbench about 7 years ago vs. a virgin stocker.

http://www.turbo-mopar.com/forums/sh...nch+comparison

There was a thread about getting the most balanced ported stocker but in the end I really don't think flowbenching an exhaust manifold tells you much about real world results that you can't figure out by looking. Its still a log manifold in the end. Backpressure will still be king.

You pointed out something a while back in that thread I made (and just posted above) and you made a point about it being a "log" and 3+4 sharing their flowpaths, but if the #3 runner sux BADLY without any interference for sharing the log to begin with in the test, then it must really be a horrible flowing port in general. It's that wretched wall and 90 degree turn in the #3 that kills flow right in the ***first*** 1-1/2" of the exhaust manifold. Doesn't matter in the test what's happening after that, when it's crapping it's pants right out of the gate. But you are correct about the "log" factor....

[RoadWarrior222]

I would say you can't be so sure too. #3 might scavenge #2 pretty well in practice.

[BadAssPerformance]

Hey Todd, you know I totally respect the stuff you build. Always top notch! But I have to disagree with you mentioning #2 as being the worse flowing, when in fact... it's flows right up there with runner #1 as they are almost direct straight shots into the collector. (with probably some interference from the log flow of #3 and #4)

You've got them backwards... Cyl 1 & 2 go into the "log" and 3 & 4 go into the "collector"

#2 sucks, and always will as it is in the middle of the log, so the exhaust gas from #2 stumbles into the log them gets hit by the following cylinder to fire, #1. This will not show up in a flow test as a flow bench test can not simiulate individual cylinder pulses.

[Ondonti]

My point is really just that flow is not what matters here, is the path of the exhaust and what happens when backpressure goes up. As backpressure goes up, the difference between the runners will start to dissapear.

At low backpressure numbers, I would say the log area will hurt performance as the two exhaust paths come together but as backpressure goes up and you lose the effect of exhaust pulses, the exhaust manifold turns into a pressure cooker. When the exhaust valve opens in one cylinder, it starts pressurizing the manifold (Couple hundred psi of pressure, down from 1000+ during peak combustion) more and any exhaust valves that are still open start suffering from reversion. This keeps happening over and over as each valve opens and closes. I think this is a bit too complicated to model on any flowbench or CAD program. I think it would also explain why some people are SO crazy about getting their tubular headers correct.

It does seem that even the worst factory turbo manifold seem to make plenty of power. Look at 2jZ-GTE manifolds and they are not good but they still can make 550whp on stock turbos. Then there is that 4 cylinder mustang with terrible log manifolds (worse then stock) that seems to run 9 second 1/4's from what I remember.
Guys who run bigger turbos and more efficient setups see less reversion and are able to make more power. Shadow must not have terrible backpressure to do what he does on the ported stocker. Reversion directly hurts power by replacing oxygen in the cylinder with inert gas. That doesn't mean there is not power to be made.

If you port the manifold and find ways to maintain the velocity of the exhaust as it comes out of the cylinder, you are going in the right direction. I was just thinking that while I don't like the location, maybe putting an external wastegate just before the #2 runner would help offset some bad things in the manifold. Vent the wastegate to atmosphere and you will have less post turbo backpressure.

I don't know the timing of the motor but how do the exhaust valves 1 and 2 compare when it comes to exhaust valve opening events. If they were spaced apart then you would be fine.

[BadAssPerformance]

Deffinitely hard to simulate with equipment readily available, unless we were in an F1 garage? LOL

There is a difference between "can make power" and "making power where you want it" and "broad power band"

Any manifold that can let the exhaust out "can make power" and restrictive manifolds probably *feel* like they are making more power as restrictions tend to feel like more low end grunt

Some well flowing headers move the power band up and you lose somelow end grunt

Obviously a well designed (for the application) header can do all of the above.

[Directconnection]

You've got them backwards... Cyl 1 & 2 go into the "log" and 3 & 4 go into the "collector"

#2 sucks, and always will as it is in the middle of the log, so the exhaust gas from #2 stumbles into the log them gets hit by the following cylinder to fire, #1. This will not show up in a flow test as a flow bench test can not simiulate individual cylinder pulses.

YES!!! I was envisioning it *backwards* in my mind.... I had a LOOOOONG day as I just got back from a wedding where preparation started from early am until at night. My bad.... Sorry Todd.

[RoadWarrior222]

Gah, I musta read something about subarus recently, got firing order confused. Anyone wanna get new cranks and cams made? 1-3-2-4 might work great with these manifolds

[Shadow]

Shadow must not have terrible backpressure to do what he does on the ported stocker.

Damn skippy!

[chilort]

You must be thinking of moparzrule on this forum. Matt is his name.

I thought he quit selling to individuals and started selling through Turbos Unleashed. Even if Matt doesn't do them for TU, I would guess that any ported manifold sold by TU is likely based on his Matt's work (but I might be wrong in thinking that).

I have one of Matt's exhaust manifolds but have yet to run it. I will have made so many changes though to the car that by the time it is back together it would not be a back to back comparison. And I don't plan on doing one.

I thought the conventional wisdom was that Matt's work was pretty damn good.

Also, which Rob M? ForceFedMopar?

[roachjuice]

Yea forced rob m