Thinking about you guys. (Isuzu v6)

[kickerfox]

And here's the finished design. I can have more of these made if you need any.

[kickerfox]

And here a low profile manifold I've been designing.

[ngpmike]

Good to hear from you again, Kicker. I too, would love to see one of these things in a Locost. My build is still on hold with the garage remodel project on the front burner. But, I have been checking Craigslist occasionally, and yes, there are lots of the correct vehicles available for not very much money. At this point all I can do is be the rooting section to cheer on others that might consider this option.

[kickerfox]

Good to hear from you again, Kicker. I too, would love to see one of these things in a Locost. My build is still on hold with the garage remodel project on the front burner. But, I have been checking Craigslist occasionally, and yes, there are lots of the correct vehicles available for not very much money. At this point all I can do is be the rooting section to cheer on others that might consider this option.

Do it! Do it naw!

As soon as my buddy finds his digital scale I'll get a final measurement with the accessories on. I'll also take some more block measurements. I'm guessing you guys would want the engine as low as possible so I'll show you more of the mods I did. To get the intake lower (like 4-5" lower) requires the throttle body be relocated. The intake head flanges are able to cut from the plenum to be used on a custom intake. The runner tubes were cut off some aluminum TV mounts I found at the junkyard but elbows are cheap. Point is it's easy to make an intake. The water pipe that is the coolant outlet was eliminated and replaced by 2 AN hoses. The coolant inlet pipe was modified (as shown below) by cutting it at the lines marked in red. Then it was rotated and welded back together. This opens up the valley for a lower plenum and throttle body.

[ngpmike]

What are the black cylinders bolted to the front of the heads?

[kickerfox]

What are the black cylinders bolted to the front of the heads?

The cam pulleys? It's a dohc engine. Or do you mean the two AN16 fittings? Those are the coolant outlets.

These?

[carguy123]

You say making an intake is easy and to a certain degree it is, but changing volumes and runner lengths changes the characteristics of the power delivery of the engine.

[ngpmike]

Yeah, the AN fittings. With the lighting in that first pic, I couldn't see the hex shape of the black fittings.

[kickerfox]

You say making an intake is easy and to a certain degree it is, but changing volumes and runner lengths changes the characteristics of the power delivery of the engine.

I'm running boost on this engine so the intake design isn't to critical. If NA then just run the factory intake. I'm just sharing my build so people can see how easy the engine is to work with.

[carguy123]

I'm running boost on this engine so the intake design isn't to critical. If NA then just run the factory intake. I'm just sharing my build so people can see how easy the engine is to work with.

Actually the intake design is just as critical and directly affects your powerband. Keep in mind you aren't under boost at all times.

[kickerfox]

I'm running boost on this engine so the intake design isn't to critical. If NA then just run the factory intake. I'm just sharing my build so people can see how easy the engine is to work with.

Actually the intake design is just as critical and directly affects your powerband. Keep in mind you aren't under boost at all times.

Actually it's not. Lets assume that the manifold design is fairly free flowing. There will always be some restriction (more on that in a moment) but assume for now they are minimal. The first purpose of a manifold is to distribute something to multiple ports. In this case that's air. The second purpose, in a gasoline engine, is to support a throttle body so that the volumetric efficiency of the engine can be controlled by the user, aka throttled. Those are the basic functions.

Lets get back to that restriction I mentioned. For a 3.2L 4-stroke engine to reach 100% volumetric efficiency, it has to draw in 3.2L of air in 720 deg of crank rotation. This is impossible unless we overcome the restrictions. One method to do so is by tuning the runner length so the momentum of the incoming air can be used to overcome the restrictions on the next intake stroke. The air bounces back and forth in the runner and, when timed correctly, creates pressure at the intake port that is higher then atmospheric pressure. You can actually reach a intake charge volume greater then engine displacement using this method. Say, 105%. Without runner tuning, say 95%. That's a 10% increase in airflow and thus a 10% increase in power. But this is only beneficial when at WOT. Any other throttle position and the user still has control over VE, as they should.

If your throttling the engine, you are reducing the VE by restricting the airflow into the engine. If you want more power, then open the throttle. Want even more? Open it further. Eventually it's wide open. Want even more? Tune the runners for that 10%. Want even more? Then raise the VE to 200% by adding a turbocharger. At this point the runner tuning is a moot point because we now have mechanical means to control the VE from 0 to 200%.

[carguy123]

You are on the right track with your thinking, but it's not restrictions that you need to worry about it's the black arts of the resonances you were mentioning.

When you change the intake design you change the delivery and therefore the smoothness of the powerband and in many cases where you make that power.

Will that be a huge issue for you? No one knows till you try it, but force feeding the engine doesn't change or correct underlying design issues.

I've worked on one intake totally by myself and redesigning it totally screwed things up. The 2nd one I had a smart friend to help, it was better, but no where nearly as smooth and good as stock. I've also read about any number of people trying it and finally giving up as they couldn't "tune" it to be as good as stock and I've not heard of anyone who has built one to be better than stock.

The manufacturers are measuring and tuning for things that you & I don't have the knowledge, capacities or equipment to do.

Does that mean you shouldn't try it - NO. Does that mean you ought to be thinking of alternative ways to use the stock intake - YES!

In other words if things don't go as you hope don't throw out the baby with the bath water and give up on the car or that engine. Simply go to plan B and worry about a hood scoop or whatever it takes to use the stock intake.

[kickerfox]

You are on the right track with your thinking, but it's not restrictions that you need to worry about it's the black arts of the resonances you were mentioning.

When you change the intake design you change the delivery and therefore the smoothness of the powerband and in many cases where you make that power.

Will that be a huge issue for you? No one knows till you try it, but force feeding the engine doesn't change or correct underlying design issues.

I've worked on one intake totally by myself and redesigning it totally screwed things up. The 2nd one I had a smart friend to help, it was better, but no where nearly as smooth and good as stock. I've also read about any number of people trying it and finally giving up as they couldn't "tune" it to be as good as stock and I've not heard of anyone who has built one to be better than stock.

The manufacturers are measuring and tuning for things that you & I don't have the knowledge, capacities or equipment to do.

Does that mean you shouldn't try it - NO. Does that mean you ought to be thinking of alternative ways to use the stock intake - YES!

In other words if things don't go as you hope don't throw out the baby with the bath water and give up on the car or that engine. Simply go to plan B and worry about a hood scoop or whatever it takes to use the stock intake.

The factory intake is a simple and effective design. I haven't measured but I bet the main runners are 15-18" long and staged at 6-8". Having driving an Amigo, the torque was there right off idle and very smooth through to redline at 6500.

The biggest issue people run into with diy manifolds isnt runner tuning (that's easy) but it's keeping pressure equalized in the plenum at high rpm when the quick inrush of air into the plenum creates a high pressure area at the back of the plenum. I'll argue the FI intakes being as complicated as NA. They're not.

The restrictions I mention are from atmosphere to the combustion chamber. All things between. They are a cause of reduced volumetric efficiency and intake tuning is one method to overcome them. Tuning an engine is all about conquering restrictions, wherever they may be.

[kickerfox]

Here it is with the AC bypassed.

[Laminar]

The manufacturers are measuring and tuning for things that you & I don't have the knowledge, capacities or equipment to do.

Ford 3.5 NA intake manifold:




Ford 3.5 EcoBoost intake manifold:


The turbo manifold basically shoves air straight to the cylinders with a very short runner length, a far cry from the NA manifold where tuning matters much more - note the TB tube length and dual independent plenums. The turbo manifold has none of that.