Question about intake mani options

[MrMazda92]

I know you meant no disrespect marcdh, even if someone else did.

Leos build is impressive, always has been. You're right about that build though, way too many upgrades to compare it to stock. As I already said bone stock ZE heads will outperform bone stock DE heads.

[MrMazda92]

+1 Things don't always work in practice like they should in theory

OWN3D!

Quite a few KL owners with ported DE heads have faster cars than you. The problem with bolt-on performance is simple, you eventually run out of things to bolt on.

"OWN3D!"

[WhiteFinish]

Why the "OWN3D!" ??

It's a good discussion and people bring up interesting arguments, but owned is just looking for wrong reply posts.

[_-Night-Shade-_]

Why the "OWN3D!" ??

It's a good discussion and people bring up interesting arguments, but owned is just looking for wrong reply posts.

Nothing, people just misinterpreted it. It wasn't directed at anyone. A lot of people have their own theories in their heads as to how things work, so whenever there is a real life practical example that disproves them, I find it funny. Lots of people make claims, few actually do the work.

Btw all KL heads are externally the same. That's why you can port the DE heads to be like ZE, and even outport them. And there is room for improvement on the ZE heads too. Eventually you can port both out to the maximum practical limits. The difference is with DE heads you'll have to do a lot more work. So call me crazy but I prefer the more practical route.

[Ryan]

I think intake is smoke and mirrors and gypsy magic.

And it basically is. You can't speculate based on sizes and shapes. The only thing I would go by is a KL that did a dyno run with each manifold in succession.

And even then, something like changing up your cams will drastically change how the manifold performs, even changing the exhaust will to a very surprising degree.

So I think we should all quit trying to say "this manifold is best!" because it honestly depends on a whole whack load of things.

Same with the heads.

The only thing I'd like to add there is that the ZE heads are partially responsible for the CR increase, as they CC a few lower than DE heads. This is NOT due to spark plug differences.

[marcdh]

The only thing I'd like to add there is that the ZE heads are partially responsible for the CR increase, as they CC a few lower than DE heads. This is NOT due to spark plug differences.

That's interesting to know. Do you know which area specifically? Squish? Roof?

[Josh]

Btw all KL heads are externally the same. That's why you can port the DE heads to be like ZE, and even outport them. And there is room for improvement on the ZE heads too. Eventually you can port both out to the maximum practical limits. The difference is with DE heads you'll have to do a lot more work. So call me crazy but I prefer the more practical route.

Pretty much what I was going to say. You can only port a DE head as far as you can a ZE, the difference is the shape. Stock for stock the ZE outperforms because its larger and can flow more air. I am more partial to a round or oval port myself especially when N/A but until I actually see a flow chart I will stick with the ZE heads

As far as the IM Ryan is right, but you can flow test them. It would be nice to find someone with abilities to do so, or run some CFD on them.

[Nd4SpdSe]

You can only port a DE head as far as you can a ZE, the difference is the shape.

I thought so. I'm sitting here thinking WTF, this something that I've never heard.

[MrMazda92]

Nothing, people just misinterpreted it. It wasn't directed at anyone. A lot of people have their own theories in their heads as to how things work, so whenever there is a real life practical example that disproves them, I find it funny. Lots of people make claims, few actually do the work.

Btw all KL heads are externally the same. That's why you can port the DE heads to be like ZE, and even outport them. And there is room for improvement on the ZE heads too. Eventually you can port both out to the maximum practical limits. The difference is with DE heads you'll have to do a lot more work. So call me crazy but I prefer the more practical route.

This pretty much sums up your understanding of cylinder heads.

The reason DE heads have more potential is two fold, the smaller ports mean more material can be removed to adjust port shape and angle. It certainly doesn't hurt that you can decide how big, or small you want to leave the ports. Bigger ports flow more air, but properly sized ports of a better angle and shape will always outperform oversized, take them out as far as you can ports, all other factors being the same. FI will change it up a bit, but the principle still holds true.

I recommend you pick up this book from your local library: http://www.amazon.com/Four-Stroke-Perfo ... t_ep_dpt_3

I've read 10 or so books on engine design(by NO means am I claiming that equates to years of hands on experience!!), and that is by far the most detailed I have found to date. I learned a lot from it, and had a few misconceptions of my own cleared up in the process. Not a bash here, for real, I think everyone who wants to improve the performance of their car should read this book cover to cover.

[fowljesse]

Pretty sure stereoking15 just has a gutted IM with the VRIS tied open...

He has that custom 3" intake that was dyno tuned.

[MrMazda92]

I forgot another + to DE heads... The potential to run OEM SLAs. Most people don't care about that, but it's a big deal to some of us...

The ZE heads do benefit from larger intake valves, I always forget that. It's a big part of the reason they outperform stock DE heads.

[marcdh]

I forgot another + to DE heads... The potential to run OEM SLAs. Most people don't care about that, but it's a big deal to some of us...

The ZE heads do benefit from larger intake valves, I always forget that. It's a big part of the reason they outperform stock DE heads.

Apparently not. I used to think this, until I measured my ZE valves and found out they're the same as DE.





All KLs therefore have 28mm ex and 32mm Intake valves.

[MrMazda92]

Fail on my part... I remember measuring this myself as well, now that I think about it. The lifters are sized differently though, for reasons I've yet to discover. Thanks for the reminder Marco, I needed that

[marcdh]

Haha any time...

Yea it is strange. HLAs, springs and retainers larger, but valves the same. All that and the springs are weaker too.

[MrMazda92]

Amen to that... I'll be running interprep springs with modified SLAs, and I'm not looking forward to the shimming process!