What about NA makes turbo hard?

[fulltimeclubber]

I've heard about puttin new pistons in a KA engine and so forth. I currently have a 90 240 but plan on gettin a junked 91+ motor and rebuilding it to around 180hp+ or so then turbo (far far away still). What about building your car for NA initially can make it bad or difficult to add a turbo later? Just curious thanks for your help.

[Open4Cycle]

Compression Ratio, ECU, and Camshaft selection would be the main things.

[themadscientist]

compression is usually too high, camshaft grinds bias the intake when a turbo wants them even or biased towards the exhuast, the maps in the computer are often not rich enough for turbo duty and cannot recognize that the engine is seeing boost.

[hotshot240sx]

other than those listed above...its gotta be wiring...rippin out the old shiz and addin the new...along with sensors and finding a custom built manifold...but if u do drop a turbo...take everything in on this page....because its a bizzzznitch....u might as well rebuild the ka from bottom to top...

[bruinbear714]

Some guy I met at a meet last week is running 10psi on his KA, with STOCK INTERNALS. He's put well over 50,000 miles on it with the turbo already.

That just goes to show that the stock internals can handle 10psi for quite a lengthy mile, but only if you're careful and drive responsibly

[96_S14_SE]

I think TY from FA.com was running a bit more then that at one point on stock internals, and reliably. As long as you do the nescisary steps to prevent detonation the stock KA usually holds up pretty well.

[fulltimeclubber]

Ok so as long as I dont change the compression ratio I can still **** around with the internals of the engine right? Would boring out the engine change the compression ratio at all? Or if I am going to go turbo one day is that something I dont want to do. I realize that with bolt ons seeing 200+ hp is a dream but with internal engine mods I'd be willing to live with 220 hp all the time without boost, but I am still not sure. What internal engine mods will change compression ratio? Thanks for any help guys.

[TrunkMonkey]

What internal engine mods will change compression ratio?

increasing boreincreasing strokedecreasing piston deck heightdecreasing piston dish volumethinner head gasketdecreasing cylinder head chamber volume

and the list goes on...hehe.

-demetrius

[unleash the beast]

speaking of a thinner head gasket, does anyone know where to find one for the ka24de?? Thanks

[Dattebayo]

you know you could run a small compression increase and a turbo at the same time, just not much boost. I have a friend with a vtec whos got a setup like that... but he has to tune it with a computer to get it to run right, even with new cams.

I definately would not run more than 10.1 with a turbo. You will get some detonation if you go much higher. (but i wouldnt do it. its like a new frontier)

[C-Kwik]

Some guy I met at a meet last week is running 10psi on his KA, with STOCK INTERNALS. He's put well over 50,000 miles on it with the turbo already.

That just goes to show that the stock internals can handle 10psi for quite a lengthy mile, but only if you're careful and drive responsibly

Actually, the stress you have to worry about the most with rod longetivity is tensile stress. This is the stress acheived from the piston's upward momentum pulling up on the rod. Tensile stress is the stress that causes fatigue, so you want to try and make sure the rods can handle this. And the engine speed is really what determines how much tensile stress a given piston/rod combo will have. Compressive stress can damage the rods, but not over time. It will not fatigue the rods. It will give when it reaches a certain amount of compressive force. Just don't detonate and don't boost over the limits of the rods(which I doubt anyone has actually determined yet) and there is no reason why a KA or any motor for that matter would have problems boosting reliably for a long period of time...even with a moderate to high boost level.

[sethulrich]

actually, as I learned it, fatigue would not be from only the tensile stress, but from the constant osciallation between tension and compression. Correct me if I'm wrong about that.

[Bryce]

c-kiwik is dead on people have been running 15psi stock internals and doing autocross for 50K miles plus with no probs. The main problem with turbo is detonation really. A well design turbo system with a well matched turbo and ic for the motor will do great along with proper engine management. 300hp on stock blocks for over 50K. but it requires knowledgable tuning and money for the right parts.also it is ultimately the tensile stress that does damage the engine, the oscillation causes stress but its the tensile that is the highest stress.b