difference in klze curve neck vs. straight neck.

[speedmazda]

just like the subject.. whats the difference? as far as i can research the cams are different.. so the straight neck has KL-31 cams, and the curve neck has the same cams as my stock 1.8? or somthing different? i went with the curve neck because it was a straight swap into my 94 GS. is there a noticeable difference between the power of the two engines?

also, i have a complete header and downpipe kit installed.. planning on going with a highflow cat and some sort of muffler(havent decided yet) what size pipe should i use? factory or go with somthing like a 2.5 inch?

thanks in advance.

[Juans_93_MX3]

I would go with 2.25 inch piping. Straight necks ZE's have KL31 cams while the curved neck KLZEs have KL01 cams (KLDE cams). K8 engines different cams. I forgot what they are called.

Power difference?
Maybe 10hp difference.

I hope you remember to swap the intake valve springs for KLDE intake valve springs and retainers. The KLZE ones break easily

I did it and it was my first time. Before that i had no effin clue what i was going to do. Its pretty easy. While your at it, get a NEW timing belt and waterpump.

If you need help PM me or ask around

[speedmazda]

http://www.geocities.com/viv95pgt/klze.html" onclick="window.open(this.href);return false;

from this link i found on the 'identifying a klze' in the FAQ section, it only shows the curve neck engine making peak torque at a lower rpm. the straight neck 165@5500 and the curve neck 165@4800. the peak power is 200@6500 on both engines.

it also notes the cam difference.

that info correct?

[onlytrueromeo]

That is correct. What most of us do is buy the straight neck engine, then swap a curve neck manifold onto it. Straight neck manifolds dont fit easily into our cars (unless you have a RHD car)

Straight necks are supposed to flow SLIGHTLY better than curved ones, but it's not a big deal.

[wytbishop]

I put the straight neck engine in my car and it's cool being one of only a few who have, but it would have saved me a lot of work to buy a curved neck engine. If I was doing it again I would.

[Nd4SpdSe]

I hope you remember to swap the intake valve springs for KLDE intake valve springs and retainers. The KLZE ones break easily

That's no necessary. They don't break that often, and only if you abuse the motor.

[onlytrueromeo]

Yeah I wouldn't say that they break often, they're just the first things that are susceptible to breakage.

[projectzemx3]

yeah i never changed my valve retainers. they crack at like 8k and i dont ever plan on taking it there.

i also have a straight neck in my car.

[JWMX3]

more like 7400rpm youre risking valve float and breaking a retainer.... why probinator puts an 8k redline on his chip i have no idea.... just makes people get rev happy and blow up their ze !

edit- oh and i forgot to mention the main difference is the curve neck is the erectile dysfunction manifold, while the straight neck is the porn star..... seems to be ALOT of EDZEs around

[Daninski]

Excuse me but I have a curved neck with the viagranator mod so I'm ready to,,stick it so to speak.

[Nd4SpdSe]

Haha, but those dysfunction manifold are suppose to flow better, so do you want performance or something straight to show off

[mx3autozam]

^^^in higher rpm's the straight oes flow better, but all around daily driver or low end torque stick with the curve neck

[RX8SE3P]

I had a big arguement with custommx3 about this one, my opinion is that while the curved neck is closer to a ZE than it is to a DE, it's still not as powerful.

The curved neck engine is out of millenias, I think. I know they come out of Eunos 800s here, is that the same car as a millenia? Australia uses weird names, our MX3 is called a 30x.... I've seen engine bays of 2.5L Eunos 800s and they are the curved neck engine. They are rated for 170HP, 125KW. I've read this from my insurance car guides site. It's also widely posted in other places that the curved neck engine has 170HP.

They use the same spark plugs as a ZE. This to me means they might have the same pistons too. I've noted that DE spark plugs are much longer than ZE ones. The Eunos 800 definitely uses ZE spark plugs. However it is tuned for regular octane petrol. The curved neck engine uses KL01 cams. Same from the DE. These keep torque in the lower revs a little better but it doesn't peak with power like the straight neck.

IMO the TRUE ZE is the straight neck engine. I like to call it the KL31 engine. The KL31 has KL31 cams, KL31 heads, KL31 ECU, KL31 throttle body, KL31 pretty much everything! It's tuned for higher octane petrol. It makes 200HP, 149KW.

Now I know that you can use either intake manifold and it won't affect you but I am pretty sure the curved neck engine in general is not as fast as the KL31 straight neck.

[Slammed6]

You should do a hybrid...It will net you the most power. I am having this same arguement over on Probetalk.com with them. Get a KLZE Straight Neck and swap over the Curve Neck manifold, it give you the lower end grunt and the Curve neck actually flows slightly more CFM than the straight neck up top.

If your doing a KLDE or KLZE you are gonna want to do 2.5" exhaust piping

[RX8SE3P]

I thought the cams were what gave the lower end grunt. The KL31 cams give power up high and KL01 are tuned for torque lower in the RPM range. Never heard of the manifold making a big difference. There seems to be a lot of conflicting opinions about the manifold and which one is actually best. There couldn't be a massive difference, if there was there would be no argument over which is best for power. That's my logic at least

I've heard of some interesting hybrids, like a KL01 engine with KL31 cams, KL31 ECU, straight neck manifolds etc. I think fowljesse has an interesting hybrid going at the moment, which is apparently rather quick too.