KA-E or KA-DE

[chr1su12]

Please don't say use the search button just have a read please

I'm in the process of preparing for another N/A KA24 build, but this time I'm not doing it half arsed, she's going all the way.

I've just never seen a dyno sheet of a KA-DE push more than 200whp. Don't start a flame war/arguement in this thread, i've seen way too many, but the point is i've never seen one.

I know the SOHC can produce big numbers as the GT3 SCCA cup cars do this.

Now is there something in the design of the DOHC head that limits power? I would of thought the advantage of DOHC will allow the tuning of the KA to be progressed much further than it's sister the SOHC. Although the trends look like it doesn't work like that.

I don't care about manifolds on either motors, I know the SOHC manifold is crap and the DOHC is OK but I won't be using it anyway, regardless of what engine I choose.

Carbs are out of the question, injected for me and yes, ITB's.

To me the DE looks like it has way more potential on paper.

DOHCSolid lifters (disregard the SL conversion for the KA-E)16 valvesPossibly a better designed combustion chamber! (someone please correct me if i'm wrong)

Would the lighter SOHC valvetrain really benefit at those extended RPM's? I'm looking to rev past 8k. Don't worry about crank, i've sorted that out

Please express your opinion fellas,Chris.

[D21_Destroyer]

My post was edited by WD for offsite linking to a competeing site for NO reason. That and I didn't even read the OP and what I had posted had nothing to do with anything...I FAIL.

[chr1su12]

I don't give a bluff about KA in boosted applications as I mentioned earlier I will be going N/A.

If you mean potential engine wise, you can't compare the mechanical tuning of NA to turbo. They're different principles.

Thanks anyway.

[SSS]

sorry to not actually give you an answer. But I'd say check out http://www.ka-t.org if you haven't already. they have threads dedicated to turboing each of these engines. And it's probably your best chance of finding people who've pushed either engine so you can see which has better turbo potential.

**** me, why even make a post in the first place? Did he or did he not say that he was building an NA motor? Open your eyes and read the OP's post before you post irrelevant bull****.

Chris, as i have mentioned before, you need to focus your efforts on the head, that is where you will make it or break it in terms of obtaining maximum VE's through out the whole rev range. Around where you want peak torque, you are aiming for 100% VE's and higher.

Your injector placement is going to need some trial and error to obtain a balance that you are happy with in terms of all out performance and idle quality. Whilst positioning the injectors to spray directly into top of the throttles at the trumpets is going to provide max intake cooling and atomization at WOT, idle quality and part throttle driveability are going to suffer. Just ask Gabe.

I'd suggest placing them immediately after the throttles, and try to find an injector that will have the best atomization for your given fuel rate requirement. At this stage, since i know what you are thinking, 370's would be ideal.

Be prepared to go through several iterations of headers based on your specific combination (dependant on cam timing for exhaust and exhaust port throat size); until you have those 2 parameters set in concrete, don't even think about building a header.

Your ITB manifold is going to require much thought, your main goal here is to get as much high pressure, cold air into the plenum as you possibly can to get intake velocity up. You will need to spend some time on the dyno to play around with different trumpet lengths, build your intake manifold and plenum to allow you to do this quickly.

[D21_Destroyer]

my bad on missing the N/A part. I would guess the DE has more potential as far as building it up goes. And here's a thought (depending on what type of fuel you're willing to run. I've never seen DE or E pistons above a 10.8 compression ratio. But i know sticking DE pistons on an E results in a drop of 1 in compression. So if you're feeling crazy you could probably stick a 10.8 E into a DE for an 11.8 compression as long as you can keep it from knocking, that ought to produce some power.

[AZ89two4Tsx]

Why don't you want to go turbo??? It gets you so much more for so much less. And I doubt you'll be able to make 200HP on either NA without a huge sum of money.

[SSS]

Why don't you want to go turbo??? It gets you so much more for so much less. And I doubt you'll be able to make 200HP on either NA without a huge sum of money.

Because he wants something different, like 8500rpm different. He has money to burn too (it seems). It's a challenge that not many undertake.

I'd be in the same boat as him if i didn't already have my turbo parts.

D21, is your justification for going with the DE purely because it has 4 more exhaust valves? No offense, but you sound like you'd take a Ford 5.4 DOHC over a 5.7 LS1. Which motor out of those two has the most potential?

I costed out building a DE head a while back with all the goodies, in parts alone including off the shelf cams, it was about $2k including the head purchase (Ti retainers, springs, 1mm o/s valves etc, not including port/machine work).A SOHC head does not cost anywhere near that much to build. About half that including converting to solid lifters. That's nearly another $1k you can spend on port work and flow bench time.

Ti retainers are not the be all and end all in terms of reliability either. Ti tends to gall, whereas the slightly heavier (not by much) OE steel retainers are durable and are meant to last. Hell, i would go with some grade of tool steel for high rpm replacement retainers over Ti for a motor that will see extended high rpm use on a circuit.

[D21_Destroyer]

sssin all honesty, i read the whole post, he mentions N/A once at the beginning, so I managed to forget about it, big f-ing deal. as to your comment about me and the DE engine, i apply what you said about reading posts, I clearly pointed out the potential for a high compression ratio as my reason for selecting the DE, if he though he'd be able to run it without knock. Never once did i mention the extra exhaust valves of the DE. as for the costs, you yourself pointed out he seems to be willing to spend a bit extra, so i wasn't really worried about it. there are also a few other benefits to the DE such as the oil squirters for the piston's, these could be installed on an E with some work as it already has the places to mount them, but it's just extra work unless you already have an E sitting around. So there are some benefits to the DE over the E, it's also a bit easier to find parts for in my experience. I personally have a ka24e, and i love it, but why not present both sides. so SSS please actually read my post before making personal attacks against me. frankly you just sound like some know-it-all jack*** high-school kid.

That said, I'm in the same boat as far as the N/A build goes. If you're willing to put the time and money in power to you, I always prefer N/A to turbo when possible. chr1su12 i don't see why the DE wouldn't be able to push more than 200whp N/A, i figure you just don't see it as often because most people choose to go turbo instead. and because like SSS pointed out the E engine is a bit cheaper, so for people trying to save money that's probably a good place to start.

P.S to SSS, I don't like American Engines. I'd prefer something german or japanese. But between the ford and chevy, i'd almost always go chevy if it makes you feel any better.

[chr1su12]

Thanks for the input guys,

The statement about SSS know-it-all-jack-****, I'd take that back if I were you.

Anyway, Once again I mentioned bottom end is sorted in my first post as i'll be running custom pistons/rods anyway. I'll choose my compression ratio (most likely 12/12.5)

SSS, I do understand that the E will be alot cheaper to work on, but lets say we put the same amount of effort into both heads, which one will provide me with the higher CFM (my common sense tells me the DOHC although we know many times we are often wrong). Having said that it is not about CFM, I could have a 500CFM rated head and achieve 50VE and make FUG all power.

There must be a reason the GT3 cars run the SOHC.

[SSS]

If you can get a velocity and flowrate advantage using the DE, go for it.

I tend to look at the extra exhaust valve as a hinderance in some respects; more valvetrain components = more inertia.

There is nothing to stop you from cutting up an "unusable" or sacrificial E head to work out what can be done. Ie, it *may* be possible to mill out the exhaust port to increase its ID and modify the short turn upto the valve seat to suit.

What is the ID of the DE's exhaust port anyway?

[sunnys14]

Go on freshalloy and search for a guy named Greaser.

He runs a 200whp NA KA. Proof of dynos so it can make your day since you've never seen one before.

[chr1su12]

Seen Geasers car, I forgot about it to be honest.

I've seen photo's of the DE's ports and I thought to myself they were alot bigger than the SOHC. Can someone clarify the difference?