Who says KA's can't handle boost

[Kenrik]

You guys are retarded sometimes. I'm not trying to state what the stock weakpoints are, I'm saying what the engine's weakness is from a design standpoint. And there have been plenty of KA's that shot a rod through the block. Open your minds guys, I promise there's more to the word than the inner lining of your large intestines. haha hosers

I saw a rod forcefully exit the block of a SR at OSW...

 

[rwdrift]

Less than $5k is not saying anything...... a VERY good turbo setup can be easily achieved with $3k. With enough money, any engine can be tuned for a forced induction setup and still be VERY reliable.

Stating the fact that the KA-T with "Less than $5k put into it" is just trying to start the KA-T vs SR thread.

I saw a rod forcefully exit the block of a SR at OSW...

That person had purchased the car on eBay with an SR that was going bad. You could clearly hear the rod knock as the car idled. As soon as he drove it in the track the outcome was obvious.

He did it as a stunt.

 

[Piner]

^Yeah that was awesome! clackalclakclak BOOOOOOOOM!!!!woosh! CHEERS!

 

[green_machine]

KA's big problem is their rod length...which is also why I don't get Anthony's signature.

Having longer rods is better (when keeping it a reasonable length). When your rod pushes against the wall of the cylinder, a force is generated. The smaller the angle is between them, the better- period.

YOU HAVE AN ENGINE THAT MAKES 100 LBf/ft of torque

Say you have a rod that’s 4 inches and a stroke that’s 3.

When the angle is greatest, it will be: 41.4 degrees.

Force (to the side of the wall) = (torque)x(sin41.4) = 75 LBf/ft

Force (upward/downward) = (torque)x(cos41.4) = 66.1312 LBf/ft

NOW,

Say you have a rod that’s 8 inches and a stroke that’s 3.

When the angle is greatest, it will be: 68 degrees.

Force (to the side of the wall) = (torque)x(sin68) = 37.46 LBf/ft

Force (upward/downward) = (torque)x(cos68) = 92.72 LBf/ft


SO you see that less force is exerted on the wall of the piston with longer rods. This is because there is less force exerted between wall and piston and more force upward or downward. This is why stroker kits are bad. They increase the stroke size and actually reduce the rod size. The wall of the cylinder will wear easily and the rod could break through.

HOWEVER, when you are getting close to 100LBf/ft in the upward direction, it will take a lot longer of a rod to make an improvement. Also, when the structural integrity (because of material and shape) and the weight of the rod are compromised because of the length, the angle between them become irrelevant because your rods will break in no time.

SR rods are shorter than ka rods. That's why a 2.0 liter with a much smaller stroke has a rev limiter only a little above a 2.4 liter. As your rpms increase, the force stays the same (if torque stays constant throughout the rpms) but there is more energy transferred to the wall of the piston. Longer rods = rev higher.

I like that signature.

 

[RICKY SILEIGHTY]

=rwdrift Stating the fact that the KA-T with "Less than $5k put into it" is just trying to start the KA-T vs SR thread.

The only way that would start anything is if that's what you want. It's like if i'm in a party, and you step on my shoe, and I swing on you it dosen't have to go there. Just cause I stated he built that with less then $5g's dosen't mean SH!T, unless you want it to. I was just happy, cause that's what I want for my car. You know what just let it go, I am saying this again like I said before this is not a KA vs SR thread so don't start that SH!T please, pretty please. Damn I don't know why ppl are so DAMN touchy about this subject ppl it's still a DAMN NISSAN! Let it be gizz.

 

[240SicknessX]

i have no doubt that this engine made over 400whp. aem ems is a great tool. but how long will it make its 407whp?. i dont think that engine will last 1 month if i drive it every day. Its too much stress on the internals and they will give up.

what turbo and how many psi?


the infamous question, dose he drift?

i hope this dosnt give the idea to anyone that a ka isnt fragile. There are a few precautionary measures you can take to prevent your ka-t from blowing up but even with a small flaw where you have a 12.70 as you start to make boost around peak tq will bring your engine to its dimense. Slowly but surly it will die.

A bad mistake that many people make when turbing their ka is the 370cc injectors or a fmu.

people, just because you have a good ka dosent mean you have to turbo it for more power. You can sell it to someone else and offset the cost of your sr swap.

 

[RICKY SILEIGHTY]

Well he only runs the 11psi 348whp daily and 407whp @15 psi for race I beleave he drag races. I only want 250whp at most cause I am running 370cc's with an safc. When I build my other engine I will shoot for 450whp, but that is really not important for now because I can't control that kind of power while i'm drifting. I think he has a T3 not sure i'll ask.

 

[Tonymac]

Having longer rods is better (when keeping it a reasonable length). When your rod pushes against the wall of the cylinder, a force is generated. The smaller the angle is between them, the better- period.

YOU HAVE AN ENGINE THAT MAKES 100 LBf/ft of torque

Say you have a rod that’s 4 inches and a stroke that’s 3.

When the angle is greatest, it will be: 41.4 degrees.

Force (to the side of the wall) = (torque)x(sin41.4) = 75 LBf/ft

Force (upward/downward) = (torque)x(cos41.4) = 66.1312 LBf/ft

NOW,

Say you have a rod that’s 8 inches and a stroke that’s 3.

When the angle is greatest, it will be: 68 degrees.

Force (to the side of the wall) = (torque)x(sin68) = 37.46 LBf/ft

Force (upward/downward) = (torque)x(cos68) = 92.72 LBf/ft


SO you see that less force is exerted on the wall of the piston with longer rods. This is because there is less force exerted between wall and piston and more force upward or downward. This is why stroker kits are bad. They increase the stroke size and actually reduce the rod size. The wall of the cylinder will wear easily and the rod could break through.

HOWEVER, when you are getting close to 100LBf/ft in the upward direction, it will take a lot longer of a rod to make an improvement. Also, when the structural integrity (because of material and shape) and the weight of the rod are compromised because of the length, the angle between them become irrelevant because your rods will break in no time.

SR rods are shorter than ka rods. That's why a 2.0 liter with a much smaller stroke has a rev limiter only a little above a 2.4 liter. As your rpms increase, the force stays the same (if torque stays constant throughout the rpms) but there is more energy transferred to the wall of the piston. Longer rods = rev higher.

I like that signature.

I was talking in relation to the KA...being a stroker motor...

And the SR can rev much higher than a KA...not just a little bit as you are stating incorrectly. The limiting factor for the SR is it's head design hence the factory rev limiter at 7500rpms.

Longer rods = rev higher = lies!!!

Bah, I jsut finished a rediculously hard accounting test and have no ambition to discuss this in detail. Maybe tomorrow? I'm over these discussions anyway...go rev out your KA's to 8k and see what happens.

 

[Kenrik]

go rev out your KA's to 8k and see what happens.

why would you want to? the power dwindles above 5500rpm... the Ka is good for it's low end torque

 

[Alchemist XL]

why would you want to? the power dwindles above 5500rpm... the Ka is good for it's low end torque

ha my ka was good til 7300 mwahahahhahaha

 

[RICKY SILEIGHTY]

If you are boosting it dosen't matter how high your rev limit is, the retired S15 JGTC Silvia race car only revved to 7500rpm, so what dose it matter how high it can rev? Now if you are drag racing that might be different. Man this thread is really becoming dumb.

ha my ka was good til 7300 mwahahahhahaha

SH!!!!!T that ain't nothing i'm going to rev mine to 15,000rpm and i'm going to run 25 turbo's i'm going rock pulling, drifting has to much drama. LOL

 

[green_machine]

I was talking in relation to the KA...being a stroker motor...

And the SR can rev much higher than a KA...not just a little bit as you are stating incorrectly. The limiting factor for the SR is it's head design hence the factory rev limiter at 7500rpms.

Longer rods = rev higher = lies!!!

Bah, I jsut finished a rediculously hard accounting test and have no ambition to discuss this in detail. Maybe tomorrow? I'm over these discussions anyway...go rev out your KA's to 8k and see what happens.

talking about the limiting factor being the head, the ka has about a 6000 rpm power limiting factor because of the cams. I dont think the bottom end of an sr can take 8000 for long periods of time. I believe the ka has a worse rod/stroke ratio than the sr (i never stated that it did) but that doesn't disprove the fact that longer rods are better. I just showed the math and explained it. If a ka had the same length rods as an sr, there would be a serious problem. However, people stroke their sr's like that and they have much worse ratio's than the ka's but they have super strong rods and usually have decked blocks. Longer is better!!! (up to a certain point. obviously a 2 foot rod would buckle when hit with a powerful explosion or could wear bearings prematurely).

on another note... midterms sucks. i just did mine earlier... i'm happy it's over. good luck on your grades

 

[Tonymac]

Longer is NOT "better". Stop saying that. There is no one right answer for anything in a motor. That's like the dumbestic guys saying "no replacement for displacement". Tell that to Ferarri. Too many variables like piston acceleration, speed, rod angle, stroke, ect have to be accounted for. To make such a blanket statement is retarded. As for revving...we were talking about abilities. Just b/c the cams suck for top end on a KA doesn't mean that it's going to "limit" its ability to rev unlike the sr which has problems keeping it's rockers in place. You rev out a KA, you put a hole in your block. SR bottom ends can take 8k just fine. Oil starvation due to a crappy pickup usually causes most of an SR's problems at the track, not rod integrity. And the KA has a better rod ratio than the SR.

If you are boosting it dosen't matter how high your rev limit is, the retired S15 JGTC Silvia race car only revved to 7500rpm, so what dose it matter how high it can rev? Now if you are drag racing that might be different. Man this thread is really becoming dumb.

No but replies like this are. Explain to me why rev's aren't important in a boosted car. I have a feeling your response will be funny.

 

[Super7]

Formula 1 cars rev to 17,000-18,000 rpm's on 3-liter V10's (last year) and make well over 700 horsepower with very low amounts of torque. Those engine's use their ability to rev high to produce power.

Less rotational momentum, small stroke and small displacement = high RPM's = big power.

There are different ways to go about getting power. A motor has a balance of all it's parts. It's finding that balance that will keep your car strong, powerful, and reliable, regardless of what motor it is. KA, SR, it doesn't matter. Ultimately you can do the same things with both givin the right amount of funding. Which one will be more expensive in the long run, I can't tell you.

Even rotaries aren't reliable at sustained high RPM's without some level of modification. They're notorious for revving to 10,000 RPM's but those are the same people that complain about blowing Apex seals all the time. Just like a reciprocating piston motor, you can do things to a rotary that allow you to rev higher. Porting, tuning, and aftermarket seals are the three most prevelant.

I've said this a million times. There are three options when it comes to performance in engines and you can only have two of them. Cheap, Reliable, Powerful... Pick the two that are most important to you.

 

[rwdrift]

^ Amen to that.

 

[green_machine]

That's like the dumbestic guys saying "no replacement for displacement". Tell that to Ferarri.

how come ferraris dont make 1 liter engines? Why doesn't ferrari put a .5 liter all motor engine aginst their 3 liter engines of other cars in f1? Why do you think it is dumb to say there is no replacement for displacement!!! It is 100% true.


ok, so why do longer rods make them weaker? When they are the same thickness as a shorter rod, they will be obviously be weaker. but.... this doesn't disprove that longer is better proportionally. It puts less strain in the walls of the pistons which is a major issue.

 

[RICKY SILEIGHTY]

No but replies like this are. Explain to me why rev's aren't important in a boosted car. I have a feeling your response will be funny.

Well that I know of my turbo will determine where my top powerband is right, so why do I need to rev to 8,000rpm if my car's full power is @6,000rpm? Isn't that why the JGTC S15's rev limit @ 7500rpm. Beside's I don't need to rev to 8,000 to spank you J/K . How did this become an argument dori dori chill, like I said it's still a "NISSAN" so why the hell does it matter. If you like the SR, more power to you I like it to, but I don't have the money to buy one so i'm going KA-T. Oh and on a side note, Nissan did build a race truck with a KA that revved to 8,500rpm, just in case you think it can't be done.

 

[j0nes]

I dunno but 400hp on a ka-t is nothing compared with what the rastas in miami have...

I dont know if you guys remember these cars but they were in the ter tech event in hialeah in december of 04.

but those guys were easily running 500hp+

 

[RICKY SILEIGHTY]

OOOOOWEEEE!!!! Damn that is SEXY, 500hp, I can beleive that. Man, nice sig. Is that how the chick's in CT look?

 

[j0nes]

well they were a bit higher, one motor was about 500hp and the other one was about 100hp+ more. I didnt take a close up of the dyno sheets, and I wish thats how the girls in ct. looked. If they did I would be married by now.