240sx engine question upgrade

[MoToR mOnKeY]

Thats right TODA has the SR22. why would it destroy the square characteristics.

[IveBeenBad]

Thats right TODA has the SR22. why would it destroy the square characteristics.

It is a stroker kit... it lengthens the stroke while leaving or slightyl enlarging the bore... square means bore = stroke...

[IveBeenBad]

yeh i just looked at the specs of the TODA kit and the bore is 87mm while the stroke is 92mm

[TurboB15Sentra]

I prefer nissans highly payed engineers to some no-name tuner. How much do you wanna bet the engineers that designed the SR sat around and pushed 20 or so lbs of boost through it for a while before they said "this thing is ready".

Besides the SR is a square motor, it revs faster and higher. The only advantage a KA has is displacement which really doesnt mean much to me. I would much rather have a fast responding SR than a sluggish 400hp KA. Not everyone is shooting for 400hp.

In an auto-x you are more than likely never going to use that 400hp to its fullest, and the SR with a properly sized turbo will give you better power delivery.

You'd be surprised at how Nissan's engineers "think". Knowing a few of them personally, I can safely say that Nissan doesn't have "performance" in mind when they build engines. ALL of Nissan's engines, up until recently, were always overbuilt. The SR has a few extra percent in it, because it was designed for turbocharging. However, that doesn't mean that it's perfect.. or that other engines aren't just as boost-worthy. There are many things that I don't like about the SR.. Why is it, do you suppose, that there aren't any 4 digit HP SR's around? Find the answers for that and maybe you'll understand why the SR isn't "all that".

As for bieng a "no-name tuner"... that's a low blow. I have a lot of accomplishments in the Nissan community.. Just because I'm not "Greddy" or "HKS", doesn't mean that I don't know what I'm talking about. Most people don't realize.. that those companys pay other people to build 99% of thier parts. Those people are the "no-name" guys like myself.

Don't get me wrong.... I love the SR.. I have been building them for 5 years. But, I hate to see ignorance influenced on uneducated people's mind. The KA is a great motor.. The SR isn't the "Holy Grail", and thier are other options out there. To say the KA is "crap".. is just flat out ignorant.

I'd be happy to go over technical aspects of both engines.. if you want to debate both.

Travis

[TurboB15Sentra]

And as for oversquare engines... what so wrong with that? It depends on what you are using it for. Oversquare engines usually make more low end TQ, and deliver a more flat TQ curve. This is because mean/peak piston speeds on-set a lot faster, leading to better intake port velocity at low engine speeds. Better cylinder filling at low RPM means faster power onset. However, as piston speeds are faster, at higher RPM, Volumetric efficiency suffers, because the piston is moving so fast, that it can't effectively draw in enough air. There are a few tricks.. like variable length intake manifold runners (KA and QR have this). This allows for a smaller runner at low engine speeds.. promoting higher air velocity.. then open up on the top end to allow the engine to breathe easier at higher RPM. Depending on how oversquare the engine is.. determines how big of an impact this will have.

Undersquare engines are the opposite. Slower piston speeds mean that the engine won't make as much low end.. and won't be as responsive at a stroker motor would be. However, since the piston speeds are less, you can rev the engine higher. This just means your powerband shifts from low end-midrange.. to midrange-top end.

Like I said.. it all depends on what the engine is intended for.. I like stroker's... slightly oversquare is great IMO.. like the KA.

Travis

[sci0n]

This is my theory.

KA = Truck Motor

I'm not bashing it for a truck motor, I'm stating the facts so keep reading before you flame me.

SR20DET = Race Motor

Now, is it just me, or does it seem that a RACE MOTOR would handle turbo and other upgrades better, then per say a TRUCK MOTOR? That's just my opinion. I'm not saying you can't do it, and I'm not saying it hasn't been done successfully. All I'm saying is it seems like the KA would have softer internals for being a Truck Motor, and the SR would handle upgrades a little better. Fact for fact, not based on "well I have a KA and its great I ownt 3 SR's" I could care less. I'm using super basic logic as of this point.

Also, seriously guys, lets stop the flamming, this isn't even talking about the freaking upgrade to the SR anymore.

[rico05]

sciOn I really don't want to be an a$$, but that last post really showed your ignorance.

BTW, the KA was in cars before it was in trucks.

Also, think about the rotary engine. My fav engine of all time. Kinda funny that Mazda offered it (12A) in a pickup in the early to mid 1970s. So does the much-praised rotary engine now qualify as a "truck engine"? Seriously, get that out of your head NOW. Yes, I used to talk a lot of smack, but after having seen what a KA24DE-T can do, I am VERY impressed. I have experience w/ SRs, CAs, and KAs and all are great engines. And that "magical" 205hp from a SR can be met and exceeded very easily with little modification to the KA. People focus on what Hi-Rev Tuners and Import Racer tell them instead of looking at the facts. The SR is a great motor, but so is the KA. But still: NONE of them beat the CA :D:D

Oh...The SR is NOT a race motor! The CA18DET is FAR more advanced. The ONLY reason Nissan built the SR was because of how cheaply they could build it! The SR is an economy engine, not a race engine. Sure, it is aluminum. "Race" motors like the RB series, 3S-GTE, 4G63, etc are all....you guessed it: IRON. And that is jsut the beginning. The SR is not the perfect engine. Here: learn to read.

http://www.geocities.com/speed...r.htmh ... ed...8.htm

Both articles have great info on Nissan engines (even though they are geared toward the CA)

[rico05]

And just a little clarification: I have seen first hand what a KA-T can do to an SR w/ fewer mods. less money spent, and less boost. I have also seen what my CA will do to an SR in the same way.

96 KA, T3 turbo, FMIC, 7 pounds, 3" turbo back beat Redtop SR w/ T25 at 14psi and more mods.

90 CA18DET, 9psi, K&N, SR T25G, no exhasut after turbo beat Blacktop S13 SR FMIC, 3" turbo back, air filter (3rd gear roll)

[sci0n]

Yes I am a noob. But you can kinda see where if that were true, how I arrived there on logic.

I just hate when people flame each other on opinions, and they don't use facts at all. I just like numbers, of course there is the one person out there who has the 600 hp SR or KA which proves everyone wrong.

So, sorry about being ignorant.

[TurboB15Sentra]

It's not about opinion... facts are facts... When you look at the break-down of each engine, BOTH are very strong and capable of making 3-4 times the power that they came with stock. The opinion comes in only when you decide which is better for your application. But like Rico said... 90% of people who go around hailing that the KA is a "piece of crap truck motor", get it from Magazines, and have no first hand experience with turbocharging a KA. You say that "It's my opinion that the KA is a truck motor." What facts did you use to form that opinion? Just because the engine is shared with the hardbody and frontier trucks? Well, I guess that makes the QR25DE a "truck motor" and the VQ series "truck motors" as well. See what I'm saying? There are advantages/disadvantages to BOTH engines... it all depends on what you plan to use them for.

I only speak from experience... It's not about flaming or arguing.. I like to debate with people online.

Travis

[gawath]

This has got to be one of the most misinformed threads I've read. It needs to be deleted so that further misinformation is not spread throughout the 240sx community. Travis, I don't think you need to argue with these "keyboard warriors".