difference in klze curve neck vs. straight neck.

[wytbishop]

The theoretical power rating of the ZE engine is 198hp. So it probably puts 160ish to the ground in the majority of cases. The only way to make more power is to increase volumetric efficiency. That means get more air in and out of the engine. Improving the intake and exhaust is the easiest and most common way tot do that, but it will probably only get you 10hp. That being said I'm sure that there are guys out there putting 200 on the ground. These are the guys chasing every little gain. Knife edging the IM, boring the TB, flowing the heads, 3 angle valve grind and on and on.

No combination of heads, cams, valves, etc. will increase your engine's output beyond 170-180hp or so. I would call 180whp the best case scenario without some sort of in depth search for added hp. If you're doing the internals, you coupld bump compression but that would hamper future boosting efforts.

You must read carefully Grasshopper.

[Slammed6]

Here's an engine bay pic. They look just like "curved neck ZE". How would you tell this apart from a 200HP curved neck? They look identical. Head codes are probably the same too. Would the cams be KL31? I guess if it was a ZE version it would have a 7 nipple disty and no EGR etc.

Here's a pics, they are found in Eunos 800

Intake Manifold- A KLZE Curve neck is identical to a US Millenia manifold when it comes to performance, BUT a US millenia manifold will have a EGR on the back center of the manifold.

Heads- They will be the same on both a True KLZE or US Millenia Motor. They will have a stamp on then KL-31 101 and KL-31 1A1

Distributor- 7 nipple Disty on KLZE, 6 nipple Disty on US Millenia Motor

Cams- They will be the same on a True KLZE or US Millenia Motor. Stamped KL-01

Pistons- A True KLZE will have the FLAT top 10:1 Compression Pistons, Where the US Millenia Motor will have the 9.2:1 KLDE Pistons

[RX8SE3P]

Intake Manifold- A KLZE Curve neck is identical to a US Millenia manifold when it comes to performance, BUT a US millenia manifold will have a EGR on the back center of the manifold.

Heads- They will be the same on both a True KLZE or US Millenia Motor. They will have a stamp on then KL-31 101 and KL-31 1A1

Distributor- 7 nipple Disty on KLZE, 6 nipple Disty on US Millenia Motor

Cams- They will be the same on a True KLZE or US Millenia Motor. Stamped KL-01

Pistons- A True KLZE will have the FLAT top 10:1 Compression Pistons, Where the US Millenia Motor will have the 9.2:1 KLDE Pistons

So there is actually a 200HP (149KW) curved neck motor and a 170HP (125KW) curve neck motor too, which are not to be confused with a DE at all, which I would refer to as a 164HP (121KW) short neck motor. I had it in my head that the Millenia + Eunos 800 had about 170HP regardless if they were from japan or not. But it seems there is actually a 200HP Japanese engine with the curved neck intake? Is that right?

[Nd4SpdSe]

Heads- They will be the same on both a True KLZE or US Millenia Motor. They will have a stamp on then KL-31 101 and KL-31 1A1

Are we sure on that. Aren't they stamped KL and not KL31? If that was the case, and with square runner IM/Heads, you could easilly and fool 99.9% of people that that it's a DE and not a ZE

So there is actually a 200HP (149KW) curved neck motor and a 170HP (125KW) curve neck motor too, which are not to be confused with a DE at all, which I would refer to as a 164HP (121KW) short neck motor. I had it in my head that the Millenia + Eunos 800 had about 170HP regardless if they were from japan or not. But it seems there is actually a 200HP Japanese engine with the curved neck intake? Is that right?

For the most part, yep. The reason why the Millenia is rated for 170hp rather than the 164hp of a regular DE is prety much due to the fact that is uses square runners in the heads and the intake manifold exactly like a ZE. The main question for debate is that is the the Millenia ZE would have 10:1, and if that extra .08:1 would make up that extra 23hp since the KL01 cams are supposibely the exact same as KL01 DE cams, but that's not to say there aren't any other tweaks.

[Slammed6]

So there is actually a 200HP (149KW) curved neck motor and a 170HP (125KW) curve neck motor too, which are not to be confused with a DE at all, which I would refer to as a 164HP (121KW) short neck motor. I had it in my head that the Millenia + Eunos 800 had about 170HP regardless if they were from japan or not. But it seems there is actually a 200HP Japanese engine with the curved neck intake? Is that right?

Yes, there is actually a Curve neck KLZE 200 HP, and a 174 HP Curve neck KL

Are we sure on that. Aren't they stamped KL and not KL31? If that was the case, and with square runner IM/Heads, you could easilly and fool 99.9% of people that that it's a DE and not a ZE

NO, actually 1993 KLDE Heads will be stamped KL-101 an KL-1A1, 94-97 KLDE Heads will be stamped KL01-101 and KL01-1A1, and KLZE heads (whether from a Curve neck or Straight neck ZE) will be stamped KL31-101 and KL31-1A1

[RX8SE3P]

So for a curve neck ZE to have 200HP, you'd need to see KL31 on the heads somewhere, no EGR, a 7 nipple disty, flat top pistons etc.

[mazdamx3freak]

3 pages on this, come on? really? straight neck ZE is the only one that will have kl31 cams in it so get a straight neck ZE + millenia IM = best combo setup n/a factory. or buy a us millenia and get n/a full race colt cams, done!

[Mooneggs]

3 pages on this, come on? really? straight neck ZE is the only one that will have kl31 cams in it

sorry to disagree... my ze came with a straight neck and kl01 cams.

[RX8SE3P]

3 pages on this, come on? really? straight neck ZE is the only one that will have kl31 cams in it

sorry to disagree... my ze came with a straight neck and kl01 cams.

That's not very common, in fact I have not ever heard of that before. Is it at all possible someone had it previously and swapped the curved neck into a straight neck?

[Mad Cow]

Is it weird that 1 of my heads is stamped KL31-1A1 and the other is KL31-101? Are the 101 and 1A1 used to differentiate the front and rear heads?

[RX8SE3P]

Is it weird that 1 of my heads is stamped KL31-1A1 and the other is KL31-101? Are the 101 and 1A1 used to differentiate the front and rear heads?

No that sounds pretty much right. Mine are the same.

[wytbishop]

3 pages on this, come on? really? straight neck ZE is the only one that will have kl31 cams in it

sorry to disagree... my ze came with a straight neck and kl01 cams.

That's not very common, in fact I have not ever heard of that before. Is it at all possible someone had it previously and swapped the curved neck into a straight neck?

This has been discussed on Probetalk. It is thought that Mazda had some KL31 cams to use up so they threw them into the latest models of ZE engines. As importers continue to bring in later and later model ZE engines several buyers of curved neck engines in the last few years have noted the KL31 cams.

[Nd4SpdSe]

Is it weird that 1 of my heads is stamped KL31-1A1 and the other is KL31-101? Are the 101 and 1A1 used to differentiate the front and rear heads?

No that sounds pretty much right. Mine are the same.

Exactly....

[speedmazda]

my motor has the kl-31-101/1A1 stampings but it had a 6 nipple disty on it, i think the mechanic took the egr from the k8 engine and installed in on my engine so he told me.. so that means its the 174 hp version.. great. this being the case, would the kl-01 ecu and vaf be the best combo for that motor?

[WhiteFinish]

3 pages on this, come on? really? straight neck ZE is the only one that will have kl31 cams in it so get a straight neck ZE + millenia IM = best combo setup n/a factory. or buy a us millenia and get n/a full race colt cams, done!

I'm having some doubts about that combination. Why would Mazda design an engine and put a straight neck IM on it instead of the Millenia?