tErbo b00st

Further proving my point

BigVinnie

iTrader: (2)

There is no debate, but do to 2.4 Litre displacement you will be able to run PSI and Boosting higher than a lower displacement engine. Even though you get less RPM rev from the single over head cam. The down fall from the single over head is that there are too many mechanics involved in the head such as lifters. The DE has no lifters and there fore has less stress wear and tear. This allows also for higher reving. I am in the process of a rebuild on my DE. I will be implicating, turbo crank bearing's, forged rods, titanium retainers and high performance valve springs, giving the engine much higher reving and durability.
Also making it a better candidate for a Turbo over the SR.
I was thinking of balancing the crank, but I would rather keep it stock for higher torque. I can give up the 200 RPM for more torque at lower RPM.
If you have a machine shop, the only cure for the E would be to custom craft roller lifter's from billet steel, that would releave the stress from the head and allow for higher RPM. Although a whole new cam would have to be designed for roller specs. It would cost alot of money. So the cheap effective cure is to go to a wrecking yard and take a DOHC and put in on the block of what use to be SOHC. Then all you need is the timing chain for DOHC. All KA blocks are compatible.
As far as Subaru is concerned, yes it is a USDM ej25, just this year it has been offered in Japan. Like I said before they know a thing or 2 about displacement. I also believe the ej25 is offered in Europe and Australia.
Didn't mean to insult you tErbo b00st I a have a short temper. I understand you like the SR, and that it was right for you. I appoligize for my attitude, see ya on the track someday.

BigVinnie

iTrader: (2)

I also failed to mention mid year 1990 KA blocks came with gouged (8:5) compression pistons.

ArticDragon

I've been reading a lot on the KA and I have this to say. You may get more revs and such out of the KA, but the highe revs will only add more viubrations to the engine, meaning more power loss. As a guy on another forum put it, diminishing marginal returns. The high the revs, the more power is lost. Since the crank is not fully counterwighted, there will be more end-to-end vibrations causing the loss of power. The best thing to do is have the crank fully counterweighted to lessen the vibration that will occur and then increase the revs.

BigVinnie

iTrader: (2)

I have implicated to machine and balance the crank. But I am scared to lose the torque that the KA is notorious for.

BigVinnie

iTrader: (2)

One thing I will admire from honda is the well machined crank's, even though the cars don't provide enough torque.

ArticDragon

Counterweighting the crank will make it lose low end torque?

BigVinnie

iTrader: (2)

YES, you are giving up torque for a smooth higher reving engine. Like tErbo bOOst said " Torque is a byproduct", if you refine the engine crank you lose your torque, but the HP curve will drop later in RPM then sooner.

tErbo b00st

I'm glad this thread cooled down .

You do have some very valuable knowledge about the KA vinnie. And make some valuable points. I'm glad you are taking the DOHC route though.

Now about counterweighting the crank and loosing torque. I would think counterweighting would be a good compromise to the reving problem of the KA. The KA is notorious for torque, but a lot of that is the displacement it has (bore and stroke also?) but that will not change when you counterweight. So while you might loose some torque, you will still have more than the SR, but you can rev higher, achieving a rev happy engine like the SR. Also adding a turbo will add a lot of torque due to the backpressure the turbo will create. And do you really need that much torque for a 2400 lb car?

I would really like to see your engine when it is done. It sounds like you know what you are doing, and you are doing it right.

Jack0423

Honestly the fact that the ka (both e and de) does not rev up to 8000 rpm really doesn't worry me too much. With the bore and stroke and rod ratio of the engine you are not going to be able to get Honda high revs. Also the cams in both motors are pretty limiting (not so much the crank). For power the biggest thing is to be able to have it within a usable range on the motor (3500-6500). I think if you go much higher than 8000 in a ka your likely to burn the oil, and fry the piston rings eventually leading to massive engine failure. I may be wrong but just from personal exp. I guess pick your engine based on what you plan on doing with your car and build from there. I personally want a very fast daily driver with semi regular runs at the track. I'm going to start with a smallish turbo like a t28r or pe 1420, or any other bb turbo with similar cmf output ranges. This is before really building the engine and I should get about 250 whp. After I can afford to build the motor I'll push the limiter up to 7250, and get a larger turbo and should net 450.

If you want a car that can rev high or has the possibility to rev high get an sr or an rb20.

All of these motors are good and I want to have a car for each to play with, but I have not won the lottery yet so I'm going with what fits my needs for now.

BigVinnie

iTrader: (2)

Not here to start an arguement , but I have been following the research of Yashio D. They won't even begin to start a project unless there has been many years of "positive research". Think of a KA24de with a much longer duration crank, and almost the same displacement of the inline RB26de. If machined and balanced you have a high reving cast iron block with forged everything, and a longer stroke. It may possibly put the RB to sleep in a few years to come.
That is what I see from the KA.
Nissan even based the QR25de from the SR20DE and the "usdm" KA24DE. Nissan has even been mentioning the return of the silvia turbo on the QR25de platform. Since the technology of the QR is so advanced bolt on upgrades are pointless right now. But once companies like Stillen or Jim Wolfe de-code the ECU the possibilities are endless. Have you seen the individual coils per spark plug........... It shares a close resemblance to that of Ferrari.

ArticDragon

Ok, here's one thing I don't get. Why would a crank that is fully counterweighted, seeing as how it already is fully balanced, lose torque. Would any kinda of vibrations in teh system make the engine lose power? Wouldn't taking out those vibrations return the power that has been lost? I don't see how any vibrations would allow for more torque.

BigVinnie

iTrader: (2)

When you "counterweight", or what some people call machine balance the crank shaft, you are actually shaving dead weight from the crank. When you remove weight you lose the early low end torque. The additional weight that would be removed produces the early low end. Since if machined the engine will be able to accelerate faster, also allowing the torque to show up later in the curve from "bore and stroke" in the mid to high RPM. This is what also allows for the smoother torque and HP curve at higher RPM. You will gain additional HP from balancing the crank, while losing the byproduct of early torque.
Yes the crank is balanced already, but only to stock low RPM spec.

ArticDragon

I see. So like to what rpm range would the torque be lost? Like up to the 3k range?

BigVinnie

iTrader: (2)

You would lose the majority of the torque from the mid 1000RPM to the mid 3000 RPM range. But a friend of mine that did the counterweight said the the RPM range went into the mid 8000 and that it was "close" to a 10 HP increase, in the higher RPM range. The torque curve wont begin to drop until the early 7000RPM range. In my opinion you should counter weight, and add high performance springs to the head before applying bolt on's. You will see a larger significant increase in HP if you do bolt on's after machining. You will be much more pleased with the results.