Want more power from your NA KA here it is!

[95hondakillr]

More stroke! Check it out heres the link

http://www.importperformanceparts.net/

[hek1620]

tight, if i had the money i'd do this before going turbo.

[RenoVado]

hey hek are you going tot the central florida meet soon??

[:: orion ::]

Worst. Idea. Ever.

...

It's been discussed at length why...but the short version is...stroking will not get you enough cubes to make up for the loss of HP you'll suffer by losing ~1000rpms off your redline.

The KA's stroke is TOO LONG already...

- Brian

[elgarvo616]

4 bangers need a higher redline to make more power to keep up with those large displacement v8's.

[HolyShiznit]

*Looks at turbo......looks at KA* smiles......

[hek1620]

yeah i just realized for the money this is not worth it. just spending the money on a turbo build up would be better.

no i didn't know about a meet. when/where/how much??

[wilfonzo]

sorry to get off topic but where and when is this central florida meet im hearing about

[InsanityInc]

what they should make is a destroker kit.

[Bigvinnie]

what they should make is a destroker kit.

Devious KA is already using NAPSZ blocks as destrokers with a 86mm stroke instead of the KA's 96mm stroke.

[DjPantsSpecR]

good god, did i not also read something about using a machined L10 crank? because that would be downright repeatable.

I'm curious as to what the new safe redline would be if you use say, ARP fasteners and carillos or equivalent.

Everyone loves the thought of spending big bucks making meager power gains through an N/A KA, i dont know why, but how can you deny it?

[deviousKA]

NA power is much more valuable. You can also save around 100lbs off of the front of your car when compared to full turbo setup (think lightweight itb's and a lightweight header). Destroked hybrids are much lighter still, and can be mounted extremely low in chassis. There is also room in s13 bay to move the engine about 1 1/2 inches further back.

Its not about the price really, you get what you pay for if your doing it for the right reasons. Consistency of power delivery = fast cornering ability.

But yeah forget that stroker kit, its just a welded and offset ground crank. You can go get this done yourself for cheaper than what they are charging. If you were going through the trouble doing that, you might as well make the journals fit chevy style rods. After that you could pick up some lentz, carillo, or oliver rods for cheap.

[1991S13]

I don't really have anything to add to this discussion, I just wanted to compliment devious on his sig

[hek1620]

florida meet when and where??

[SSS]

devious, aren't you running around the 2.5L displacement with you're ITB'd KA?

[deviousKA]

Yep SSS, im right at 2502cc with that sohc. I am running stock stroke with 91.1mm bore.

I built it long ago just trying to gain decent compression ratio in sohc without welded chambers. Accomplished 10.7:1, and still running strong.

[HolyShiznit]

I don't claim to know anything about squeezing power out of a NA KA, so I give the guys props that DO. However, I will argue about the total weight thing with a turbo kit. It wasn't until I added my ungodly sized intercooler that I gained a decent bit of weight. For the record I gained 17 pounds as compared to the STOCK engine set-up. After I added my bigger intercooler the NET change was an additional 6 pounds, for a total of 23 pounds gain over stock engine set-up. I DO UNDERSTAND that a lightweight header and ITB's instead of our monster Intake Manifold's would weigh less.

However, full interior with a little under a 1/4 tank of gas my car weighs 2550 w/o me in it. So to each thier own.

Whether it's hauling *** or going through the twisty's, do your thing guys.

[InsanityInc]

Quote »Its not about the price really, you get what you pay for if your doing it for the right reasons. Consistency of power delivery = fast cornering ability.[/quote]Bingo. I tell that to people all the time who just want to throw a turbo on a KA to make a bit over 200whp. Sure, if all you want to do is drag race, go for it. Otherwise, the throttle response, lack of lag and linear power delivery of an NA engine are key for any kind of road race or similar event.

[SSS]

Yep SSS, im right at 2502cc with that sohc. I am running stock stroke with 91.1mm bore.

I built it long ago just trying to gain decent compression ratio in sohc without welded chambers. Accomplished 10.7:1, and still running strong.

That would have to be right at the limit for boring out a KA block right?

I am considering have the crank welded and offset ground to bring total stroke to 100mm, along with the 90mm overbore that is on the cards, as you said to hopefully give me a better choice in forged rods/pistons from the chev/ford guys.

In your opinion, would you run that 91mm bore with near stock cr, and a maximum of 25psi boost?

[s1ndicate]

Devious KA is already using NAPSZ blocks as destrokers with a 86mm stroke instead of the KA's 96mm stroke.

Interested in that statement, can you explain?

86mm stroke = High rev? You would inturn loose some power/torque down below?

L20 crank and rods drop right in?

This is interesting if so, my main goals for my other KA are a decently high revving KA (8-9k) with a GOOD cam and either carbs or ITBs.

[deviousKA]

I would say 91mm is far beyond the limit that you would want in a boosted application. Main point of interest in the diagonal cooling passages that run in between bores, from the deck down. Where these passages cross the cylinders is the thinnest point of the entire cylinder wall. You will have take hot spotting into huge consideration, thin material + heat = bad. In my opinion I dont think you should venture into enlarging the bore any more than you need to, 91mm is to far.

I might have some information that would interest you though, regarding your stroker plans. Available in 90.2mm bore, is a great variety of affordable off the shelf forged pistons. These pistons are designed for the ford modular v8/10 engines (4.6, 5.4, 6.8 triton). I say these may interest you because of their compression height (or compression distance) is a few mm shorter than ka24 (4.6l=31mm KA = 34mm) and would be well suited depending on your rod configuration. Your going to need to run a piston with a shorter compression height, this will help with the rotating assembly characteristics allowing your to run as long of rod possible. This will also keep the piston lightweight. You can pick up a set of these modular ford v8 piston in aftermarket forged (ross, diamond, probe, etc.) for half of the price of an import forged piston, or less.

But before you were to get set on pistons, you will need to find an appropriate rod. SBC (small block chevy) has a good variety of rod lengths (oem and aftermarket) and most of these run a 2.1" journal (ka=1.96"). These can be fit, but will require extra material around the entire journal as well as some added to narrow the journal. All good things to make your machinist unhappy.

You could probably find a domestic V8 rod with a smaller journal, as the racers over here have been playing around with that a lot lately, but journal width is equally important. Most of the older V8 run very large diameter journals (2.1"+), so you will want to look into more modern engine, such as the modular ford v8's and some of the newer chevy ohc. Ebay is your friend.

If anyone else is reading this and gets hip to those cheap modular ford v8 pistons thinking they can make them work in their ka (like for a turbo application). Ask me and I will explain why they cannot be used. These would only be useful in a custom rotating assembly where the characteristics can be manipulated to bring them up to top deck. Quench is your friend, but can turn on you . If more clarification is needed, just ask.

[deviousKA]

Interested in that statement, can you explain?

86mm stroke = High rev? You would inturn loose some power/torque down below?

L20 crank and rods drop right in?

This is interesting if so, my main goals for my other KA are a decently high revving KA (8-9k) with a GOOD cam and either carbs or ITBs.

Its fairly complicated, the short answer is no you cannot destroke the KA that way. When destroking or stroking you cannot think of it as changing the current engine, you will have to design that engine from the ground up taking everything into consideration.

Ill just lay out a few things:

KA block, to tall to do any significant destroke.

L20b crank/rods, can be physically modified to fit, but see above ^

[SSS]

I would say 91mm is far beyond the limit that you would want in a boosted application. Main point of interest in the diagonal cooling passages that run in between bores, from the deck down. Where these passages cross the cylinders is the thinnest point of the entire cylinder wall. You will have take hot spotting into huge consideration, thin material + heat = bad. In my opinion I dont think you should venture into enlarging the bore any more than you need to, 91mm is to far.

I might have some information that would interest you though, regarding your stroker plans. Available in 90.2mm bore, is a great variety of affordable off the shelf forged pistons. These pistons are designed for the ford modular v8/10 engines (4.6, 5.4, 6.8 triton). I say these may interest you because of their compression height (or compression distance) is a few mm shorter than ka24 (4.6l=31mm KA = 34mm) and would be well suited depending on your rod configuration. Your going to need to run a piston with a shorter compression height, this will help with the rotating assembly characteristics allowing your to run as long of rod possible. This will also keep the piston lightweight. You can pick up a set of these modular ford v8 piston in aftermarket forged (ross, diamond, probe, etc.) for half of the price of an import forged piston, or less.

But before you were to get set on pistons, you will need to find an appropriate rod. SBC (small block chevy) has a good variety of rod lengths (oem and aftermarket) and most of these run a 2.1" journal (ka=1.96"). These can be fit, but will require extra material around the entire journal as well as some added to narrow the journal. All good things to make your machinist unhappy.

You could probably find a domestic V8 rod with a smaller journal, as the racers over here have been playing around with that a lot lately, but journal width is equally important. Most of the older V8 run very large diameter journals (2.1"+), so you will want to look into more modern engine, such as the modular ford v8's and some of the newer chevy ohc. Ebay is your friend.

If anyone else is reading this and gets hip to those cheap modular ford v8 pistons thinking they can make them work in their ka (like for a turbo application). Ask me and I will explain why they cannot be used. These would only be useful in a custom rotating assembly where the characteristics can be manipulated to bring them up to top deck. Quench is your friend, but can turn on you . If more clarification is needed, just ask.

Thanks for that gabe, you never cease to amaze!

I'm awaiting some pricing on 89.5mm Arias KA24E specific pistons; from what you've told me i'm hesitant to go with a larger bore now, as KA blocks are not as readily available and as cheap as in the states.Last thing i want to do is blow chunks out of the block

Ideally i'm aiming for 2.6 L final capacity, which can be achieved with the aforementioned 90.2mm bore and a 102mm stroke.

I really have no problem with a reduced limiter if need be, as this engine will be in my track only car.

[SSS]

Ok, just to clarify some issues:

Arias have the 4.6 modular V8 piston as a 90.7mm bore piston. Was that figure of 90.2 just a typo or is aria's catalog wrong?

Say i use the modular v8 piston, and with an offset ground crank to utilize stock KA length rods.With the compression height difference between the modular piston and the KA piston being 3mm, this means essentially i can only get away with a max 3mm increase in stroke, without using a shorter rod, correct?

[deviousKA]

With a 3mm shorter piston, that would allow for 6mm total additional stroke. When calculating deck height stroke/2 + rod + piston.

I looked up that bore size real quick, and I think that size of 90.7 that you got is the .5mm oversize. STD bore size on the modular should be 3.552"/ 90.22 mm. Arias probably doesnt sell a std size for whatever reason.

Check out probe industries, the best high quality piston available aside from mahle, and not expensive!http://www.probeindustries.com...h.htm

I get all my custom pistons done through those guys, tolerance is top notch.

Stock ka rod would be the easiest way to go with a stroker, less overall journal modifications. You could always wait out for some forged aftermarket ka rods whenever they come around, and be able to swap them in.

Id say you could feel rather safe with the 90.2mm bore, I wouldnt be to weary to run that in a boosted app.

Something to consider anyways, custom pistons are going to run no less that $400 US without rings, those modular you can get 8 for that price and build 2

Oh and btw, those pistons run 22mm pins, ka is 21mm. Easy fit with some rod honing, I run 22mm pins in the 2.5.

[SSS]

Fantastic. Thanks again!Shot off an email to Probe on those Ford pistons.That works out perfect in regards to using the stock length KA rod with a 102mm stroke.

[deviousKA]

I realized it would come out to just what you were after, after I posted it.

Good luck on your build SSS. Be sure to show us the crazy TRX from down under when your done

[SSS]

Don't you worry about that, i certainly will

Had another question for you too.I've found a set of BBC H beam rods from Manley, which are 165.989 mm length. Since the KA rod length is 164.99 mm, i know that the pistons can be flycut by 0.99 mm to bring the rod/piston height down to the correct length.What i need to know is, the Manley BBC rod has a 24.77mm pin bore compared to the ford mod V8 piston pin bore of 22mm. What would be preferential to get this rod to work with that piston? Bush the pin end of the rod or machine the pin bore of the piston? I'd prefer to bush the rod, as i wouldn't feel comfortable having the piston pin bore machined to fit.

[Mr.Sandman]

dont forget about cutting of the CAT, some states dont even have emissions which makes it great.

[deviousKA]

You shouldnt have any problem fitting a bushing to reduce the size. Im not sure if that bbc rod you speak of is originally bushed or not, but it could certainly be honed out and replaced regardless.

Your local machinist should have catalog full of misc. universal bushing inserts. They would be the one to talk to regarding that, as that would be a final fitting process.

You would probably want to stop in or give them a ring before you order any components, just to get their opinion and to make sure they can do it.

Or, you might want to contact probe, they are very "custom oriented" and might be able to offer the pistons with a larger pin size for no extra cost. Other piston manufactures may be able to offer something similar as well.

I would say both methods are equally proper, although one method may offer weight advantage that the other may not. 22mm pin is plenty large to take any abuse this setup would put out.