need a little guidance and i wont argue

[overboostn07]

i have looked around and couldnt decide on either sr20 or rb20. but after looking at it for the price of the swap i could have a turbo ka prolly pushing more power and torque than either of those two and also not be like anyone else around here. they all have either sr or rb25 or vq30tt. so what my decision is, turbo the ka. imma get another motor to built mine ticks in the valve cover and kinda scared to use this motor. few questions. k ive seen pistons shatter and melt cause of boosting a higher compression motor. i cant find out what compression the ka runs at. is it ideal for about 15psi? i wont ever run more than that. also is the bottom end strong enough to handle 350hp? i wont run any more than 370ish. maybe run a sneaky peak nitrous no more than 60 shot. i know the stock clutch wont hold hp so i have that covered. to run 15psi, 60 shot, and some how get a safer yet higher rev out of the ka, what do i need or will new oem parts and or cleaning do the job and be a reliable, yet a weekend racer .also is there any little tricks anyones discoved to get a little more hp or torque just by tinkering around in the engine bay?

[Fenvy]

hey, I have a sr20det, not just stock swap, I have upgtraded intake manifold, exhaust manifold, camshafts, bigger injectors, power fc, bigger turbo and all that stuff

if you have money to blow over the course of the year, I recommend to go with rb25 motor. Sure it is more expensive initially but all those upgrade you add later on will give you tremendous amount of gain.

there is a saying, "there is no replacement for displacement". Well, 2.5 liter is more than 2.0, it also has 2 more cylinder, probably 1 extra turbo, can take a lot of abuse probably more so than sr20det, and probably isn't so old like rb20

I have spent over 5000+ in performance upgrades on my sr20det. If I can do it again I would start it off with rb25dett

[AZhitman]

My experience has shown that even a good, solid stock KA can only handle about 8psi reliably, and even then you're shortening its lifespan.

Build it with forged 8.5:1 pistons and forged rods and 15psi is no problem.

You're never going to make it a high-revver, but the torque makes up for that.

Plan on $5-$6K for a GOOD rebuild and all the parts you'll need for 15psi, and DON'T skimp on injectors, fuel system and engine management.

[WDRacing]

We have a few members putting down just over 300 WHP on a regular basis with no issues at all. We have one member(NissanFanatic) who's over 400whp. All of which has been done on a completely stock motor.

These motors were however in really good running order prior to seeing any boost.

Then there are guys like Greg, Foster and I who have either locked up a motor or tossed a rod right at around 300. I contribute these to bad tuning and oil issues.

I feel confident in saying a stock KAT if tuned well can put down 350whp without any issues. But it needs to be put together well. The oil pressure must be good, the cooling system should be improved and the tune should be done very well.

If I were to rebuild a KA, I would NEVER install factory parts. The hassle of a rebuild makes spending the money for the added security of forged internals WAY worth it. Foster rebuilt his motor with forged pistons and factory rods. Thing was awsome until he tossed the #3 rod through the block.

Trust me, just buy the forged rods and pistons. Then you'll be plenty strong enough to do whatever you want.

The stock compression is 9.5:1. The issue with compression isn't so much what the internal parts will handle. Its will the tuning be able to keep the motor from detonating. Timing retard is a big issue here.

Detonation is all based on octane really. Obviously the higher the compression the more the Air and Fuel are squeezed. More squeeze means more heat. More heat means more power, right up to the point where the fuel ignites prior to the spark plug firing. The flame front tries to drive the piston back down the cylinder as the crank forces it up. Thats where you get burnt pistons and crack ring lands.

In a nut shell, the lower the compression the more boost you can run for a given octane rating. For every octane point you increase, you can effectivly increase boost 2 psi.

However, by lowering compression, you lose off boost driveability. For a low boost setup, 15 psi or less, I see no reason why the stock compression won't work. I ran 20 psi on stock compression pistons. The key is tuning. But we can get into that in a different thread.

I hope I made things a bit more clear and not more complicated.

Welcome to Nico and KAT. If you can't find the answer here, it probably doesn't exist.

WD

[AZhitman]

^ There you have it.

Genesis to Revelations, the KA-T Version.

[S13FX]

WOW WD that is one of the best explanations on detonation I have heard in a long while.

[nissanfanatic]

I'm a firm believer in the KA. After I finish school here in Va and go on deployment, I'm gonna switch to a larger setup and go for over 500whp on a stock internal engine.

[NateDogg]

Maybe the army will subsidize your parts as R&D on mobile bombs.

FYI I'm at 300whp on a custom tune I did and everything's good so far. I think a big key to reliability is modifying the PCV system. This can help keep oil out of the intake charge (increase power and 'octane') and lower pressure in crankcase which IMO can reduce chances of blowing ring lands.

[gaehrings13]

How do you go about modifying the pcv system... what did you do to do that?....THANKS!

[adrianfromthecastle]

zerothread?id=223621http://forums.nicoc ... 44honestly, if i had the money... i'd go with a rebuild then that ^_^

[Chezedik]

WTF!?!?! NO!

First, blowby saves ringlands, not the other way around. Your chance of detonation goes up as ring end gap is decreased, no questions. Why is this? Well, keeping pressure inside the combustion chamber is the exact same as raising compression with the same level of blowby. By having a higher dynamic compression in the cylinder, you will have a higher risk of detonation. With a proper tune this may or may not be an issue. But it does give you a larger room for error. Removing the PCV will do NOTHING to help this, and will only increase your emissions by 20+%.

What destroys the ringlands is detonation. What happens is there is a huge pressure increase, followed by a drastic pressure drop. This creates an intense vibration, resulting in the ping sound we know. Also, as WD stated, this happens long before the engine is ready to have the piston come down. This will create a situation where the pressure needs to vent. In an extreme enough situation, it will break the ringlands in order to do this. This will also happen over a long enough time, when fractures occur in the ringlands.

Oil has such a resistance to burning that it will not affect the engines knock resistance in any way. But more importantly, the engine does not run without some amount of oil in the combustion chamber. This oil will serve to lube some parts that will not get lubed as well normally, and it will increase knock resistance, assuming it is not allowed to linger in the combustion chamber.

We are not working on opinions, just fact. To offer opinions on how an engine works is irresponsible, since it will serve only to pollute the forum with misinformation. A lot of these noobs take what some of the more experienced members say, as fact. As far as what you are doing, it serves only to pollute the environment, for NO power gain.

[nissanfanatic]

Modifying your PCV system does keep your oil cleaner which in turn provides for better lubrication.. Which in turn helps to prevent rod knock, the "tied for 1st" cause of dead KAs..

[WDRacing]

The KA does seem to be prone to rod knock...

How are you guys "modifying" the PCV system?

[Chezedik]

So does changing your oil.

[WDRacing]

IMO, the less blowby the better. Harness every bit of the combustion process will yield better more efficient results. Lessoning the need to increase boost.

You should never depend on blow by to save a piston ring or ring land. At that point you need to upgrade your parts or tune your setup accordingly. I wouldn't even consider it a margin for error.

Detonation is easily kept at bay. There are various methods to increase boost and keep knock from apearing at all.

WD

[Chezedik]

Agreed, a good tune on some Total seal rings is good for a lower boost setup making the power of one of higher boost.

[nissanfanatic]

So does changing your oil.

With the excessive presence of gasoline+whatever else becomes of gasoline and air burning sitting in your oil, it will break down before three months..

I use the same method Orion uses.. He posted it up a while back.

And as for your little rant, blow-by oil being sucked into the combustion chamber DOES lower the octane rating of fuel... And pressure in the crankcase can cause more oil to be pushed into the intake tract..

http://www.supersixmotorsports...s.pdf

Blow-by doesn't "Save" your ring lands..

[WDRacing]

In fact, you want as much negative pressure as possible in the crank case to insure ring seal. More seal leads to less contaminants and more power. Hard running motors should have the oil changed every 2000 miles at the longest interval. I also swap my filter out every 1000. Its simply to cheap not to do and you effectivly improve the filtration a ton. Not to mention oil flows better through a clean filter, which improves pressure as well.

And for the record, I'm the man...LOL.

[nissanfanatic]

I always hit 3 months before I ever hit even 2000 miles..

[fayceoff]

What's a Fire Controlman doing in Gainesville? Haven't run across many of us squids in the forum. hoo-yah!

/end threadjack.

[Florida240sx]

I change mine about every 1000miles. Running 15psi gets it burnt pretty quick

[Chezedik]

Thank you WD, you understand me in a totally not gay way. Yes, if you build a performance motor, you can throw away that trite business of 3K or 3 mo.s. Also, yes, if you can prevent detonation, you save your ringlands. It's as simple as that. Also, you tell me that it hurts octane rating, but (and as I pointed out) if the intake charge clears, it will not increase detonation. The increase in detonation (or at least possibility of) is caused by hot heavy ends being left in the combustion chamber. If you have any sort of boost, you will not have an issue. And if you are not in boost you will not have a high enough load to cause ping. But to each his own.

If you hold supersix to be the authority, then so be it.

[NateDogg]

I modified my PCV system by implementing the following theory found at :

http://www.beesandgoats.com/bo...l#PCV

I used a 45* slashcut facing away from the inlet charge to help create a vacuum in the crankcase and lower pumping losses (ie more efficiency) and other reasons mentioned above.

Chezedik: I also did not increase emissions 20% because I used a factory PCV on the top of my Endyn (theoldone.com) breather kit and routed it back to the turbo inlet pipe. I believe this is what the DSMs have for PCV systems.

Also, are you saying that an engine that is burning oil under vacuum will not burn oil under boost?

BTW I made 290whp at 9psi on a stock motor running 10.6:1 AFR and at 14* timing (enthalpy ecu). I've since tuned it for 12.5:1 and 20* timing with 94 octane. Butt dyno says at least another 20whp. Maybe im doing something right...

[overboostn07]

well i appreciate the help. im not loaded to do expect to spend some cash. i dont hear of anyone really talking about an rb20 or seen many, will they drop right in and transmission hook to stock driveshaft? or am i not in any better or a situation than having a ka-t? i seen a stroker kit for the ka, imm going to get it. forged pistons and rods "9:0:1" and stage 3 hks cam kit allowing up to 9k. but will the sr20 cam work on the ka cause thats all alot of things are for. which brings me to ask, what are the diff between the ka and sr, they look the same to me besides the turbo of course and valve cover. and the ka is 2.4 and sr 2.0. what i was thinking instead of spending money on a swap get stage 3 cam kit if the sr20 will work in the ka, forged pistons and rods, hks full gasket kit, all new seals and bolts, t3/t4 turbo and manifold, full 3" exhaust, 60 shot nitrous, front mount ic kit, sr fuel injectors and fuel pump, larger oil pan and external oil cooler, tune the ecu if its poss? what obd are they anyway? its a 93 se? or an rb20, 2.0 v6, thinkin it can handle more and its turbo, but its 2.0, will the displacment make that big a diff? if i went with the ka, what can i use/order that will work or swap over from the sr20?

[nissanfanatic]

I modified my PCV system by implementing the following theory found at :

http://www.beesandgoats.com/bo...l#PCV

I used a 45* slashcut facing away from the inlet charge to help create a vacuum in the crankcase and lower pumping losses (ie more efficiency) and other reasons mentioned above.

Chezedik: I also did not increase emissions 20% because I used a factory PCV on the top of my Endyn (theoldone.com) breather kit and routed it back to the turbo inlet pipe. I believe this is what the DSMs have for PCV systems.

Also, are you saying that an engine that is burning oil under vacuum will not burn oil under boost?

BTW I made 290whp at 9psi on a stock motor running 10.6:1 AFR and at 14* timing (enthalpy ecu). I've since tuned it for 12.5:1 and 20* timing with 94 octane. Butt dyno says at least another 20whp. Maybe im doing something right...

lol power production is no way of proving what you did is right!

[Chezedik]

That article seems like a good way of doing it.

Curious, they said that oil will lower effective octane as well, who has tested this? I have never seen tests on it, and until then, I have to believe that it acts like water injection, rather than lower octane fuel. I think this because of the need for it to be in vapor form to burn, which would require a good amount of heat to overcome the latent heat of vaporization for oil. I would guess that it would be at least 1K btu. But this is purely speculation, and should not be treated as anything more.