First of all, to get the formalities out of the way, yes a CA18DE is stupid and slow and I would be much better off putting a turbo on it or going LS1 or something.

That being said, I have a CA18DE in decent shape. It will be refreshed and driven until it is done, and then I would like to do an 'all out' high compression NA build. I have a spare CA18DET from which I can utilize the block (since it has the piston squirters) and slowly build it up in the meantime. When I say 'all out,' I would still like it to be somewhat reliable and street-driven, with a tolerable idle and such, so I am not really sure what kind of a realistic power goal I could expect. I already have all the various bolt-on parts, but there are some more involved mods I would welcome input on:

Cams
Since I have the head opened up, it is tempting to put cams in it already. I would prefer a combo that would work decently both on the internally stock motor and on the high compression motor later on. I am deciding between:
-Tomei Poncam
-Tomei 260 duration, 8.8 lift, Tomei valve springs
-Tomei Poncam intake, Tomei 260 8.8 exhaust, Tomei valve springs
Would anything more aggressive be dumb on a street car? Any other suggestions?

Pistons
Spool sells 13:1 pistons for the CA18. It is also possible to have custom ones made. What would be the maximum 'safe' compression to go with if I want the motor to last a bit and be able to utilize premium fuel from any gas station? What about E85?

Crank
The crank will be knife-edged and balanced. I am deciding between a stroker crank or factory stroke. Currently I am leaning toward retaining the factory stroke for reliability and making a perfectly square motor.

Are there any other major internal mods to be done?
Any other tips on how to reliably squeeze out as much out of the motor as possible for a street car?
Along the way I am sure to have more questions, regarding the management, injectors, and such.


I have also been scouring the internet for built CA18DE's for information and inspiration. So far I have come across a couple of F3 cars and Datsuns. They seem to be around 180hp, but the most extreme one I found was 241hp in a Datsun Stanza (old RWD one) which won an Australian under 2L sedan racing series in 2003. Feel free to post up any that you know of.

Cheers.

For high hp NA, the more cam the better. That being said, maintaining streetability is going to limit you to around 270° of duration. You want a longer duration on the intake than the exhaust. Hot air moves easier than cold air, so the exhaust can move out of the combustion chamber faster than cool intake air can move in.

I think 12:1 might be the limit for pump gas, but you're going down a rarely traveled path, so there isn't much more information. If you switch to E85, the compression ratio potential will increase considerably. I would say that 14:1 would be completely in the safe range for E85, but once again, not much information around.

I say stroke it. When you're NA, you want as much displacement as possible. Although this may limit your max RPM capabilities, I see no reason why 8K RPM won't still be attainable.

If you stroke the rods have to be replaced.

Take a good look at getting the head ported and gasket matched. The exhaust ports are especially bad. Plan on a good intake manifold. The only tried and true option is from CPC. They're not cheap, but I have one and I can tell you they are top quality.

You're going to have to drop some BIG money on a custom header. It will cost you, but it will probably be one of the biggest power gains you'll get out of this motor. You really need to increase the exhaust scavenging as much as possible to make any kind of reasonable power.

To be honest, this will cost you a lot of money and likely won't make as much power as a lightly modified turbo CA, will be less reliable, less drivable, and less fun all around.

There is a reason this is basically never done....

Thank you for the information.
I already have a Fujitsubo and an HKS header. The HKS one will definitely not clear LHD steering and it is hard to tell if the FGK one will either. One of them will be getting modded. As for an intake, ITB's would probably be best, but I am not sure if they would be worth the trouble. I already have the PNT manifold for a Q45 throttle body, so I may utilize that somehow. Other than that, I have a bunch of other bolt-on junk on order, such as the Ross balancer, Gizzmo gaskets, accessory pulleys, and etc. Luckily if I ever realize how stupid building a CA18DE is, I can transfer most of the parts to a turbo motor.


Here is some neat NA CA stuff for now.
[youtube]http://www.youtube.com/watch?v=u2O1AVnzrY4[/youtube]
[youtube]http://www.youtube.com/watch?v=ai7XYdGo4qA[/youtube]

If you want to learn how to build an NA motor I suggest you go to Hondatech and do a lot of research. The specific numbers will apply to Honda motors, but the principles are the same no matter what you're working on.

For compression, it all depends on the cams. Static compression is just a number, just like boost. Dynamic compression is the only thing that matters. There are high horsepower B series engines running 13:1 reliably on the street on pump gas. But that's because the cams have such a large profile that they bleed off a lot of the compression. The cranking pressure is only slightly more than stock. I don't think you could run 13:1 static with a 260° cam. I may be mistaken as it's been a while since I read up on actual numbers, but iirc a lot of the 13:1 street guys runs 290 and 300 degree cams. They have like a 270°@0.050", which is massive. I would convert to solid lifters for an NA motor. It'll be a pain, but I think it'd be well worth it.

Idle quality can be helped by raising the idle some, a fair compromise IMO. You will suffer from a lack of bottom end torque, but there are ways around that as well. A lot of people think if you extensively port a head you'll lose bottom end, but a really good PNP will sustain velocity at low rpm and provide amazing flow in the top end. I was wanting to build a 240whp B20 for an Integra and I noticed a lot of the people in that power range still had 130wtq at 3000rpm on the primaries. Which amazed me because my GSR had 114wtq in VTEC, and it already pulled quite well. We don't have the luxury of two can profiles, but it's possible to have a very wide, usable powerband. I would look into Portflow and see what they could do with a CA head. I'm sure they could get the blueprints for them to see how far they could take one. I know they can make a B series head flow 300+cfm on the intake side.

I don't see any reason why you couldn't run 9-9.5k rpm. Hondas run that with 5mm more stroke than we do, and I think we have about the same rod to stroke ratio. You just need hardware that's up to the task. Run over to Hondatech's All Motor tech section and you'll learn a lot of useful info.

Will do, thanks for the tips, this will definitely be a learning experience.

Are there any actual numbers showing how much better the Euro 4-port head flows? I have considered sourcing one. Though I do have two good JDM heads that it would be a shame not to use, and I already have the butterfly valves and shaft deleted from the intake runners. One thing I am curious about is if it would be possible to machine out the center dividers from the dual ports on the head and runners, thus effectively turning them into giant single ports.

Iirc, the 4 and 8 port heads flow roughly the same. The 4 port might do a little better up top, but I'm not sure. I think one person has machined an 8 port into a 4 port, but idk if it'd be worth it or not. The biggest advantage of a 4 port is fuel flowing over both valves keeping them clean. Whereas half the valves/ports like to get gunked up on 8 port heads. I think flow would be about the same between the two if they were both properly PNP'd. Idk if there is a wider selection of ITB manifolds for one over the other, but that is something to consider

Based on flow rates, under 300hp, the 4 port provides no gains whatsoever. The 8 port will help with gaining some bottom end power back. The larger the cam, the more noticeable the power difference will be. Keep the 8 port.

I thought that was characteristic of the butterflies, not the head itself (although you only get the butterflies with the 8 port head, so it's a good point). I had forgotten to mention that. Having those butterflies speeds up the intake velocity at low rpms and really helps with low end torque. GSRs have a dual plane manifold and it make a huge difference in how low VTEC can engage and overall torque on the primaries. Our butterflies do the same thing for us.

Destroke a CA20 block with a CA18 crank and custom rods, bolt a DE head on it with some long solid lifter cams and wind that b**** up!

Oohhhhh, that does sound fun!