Turbo or Not Turbo..? THAT is the question...

[fo0manchu]

Stock KA on boost is fine. Doesn't matter what year or compression. Mine is a 1995. 7-10 lbs of boost easy. I have been running this for a couple months now in my wagon. So I am speaking from experience. N/A KA was super fun too, and it was fun to drive it that way and then feel how it is boosted.

 

I would rebuild the motor since the head is already off. If it was still on you could have done a compression test and see what is up. If you just get new seals and head gasket and then find out something was wrong with the engine after you put everything together, that would suck big time.

 

If you are planning to run around 7-12 lbs of boost, then you will be fine with the stock engine as long as you tune that thing right. If you want more boost, I would start looking into rods and pistons.

 

If I were you, I would run the stock KA first to make sure everything is good and have some fun with it. Then if you decide to boost it, then go for it. Unless you are planning to build a beast of a motor.

 

If you want more info, you can read stuff at ka-t.org or nicoclub forums.

[72240z]

Called it lol

[datzenmike]

What is the piston dish on a DE motor anyway? Truck and car pistons the same?

 

And what is the factory compression supposed to be also?

[72240z]

What is the piston dish on a DE motor anyway? Truck and car pistons the same?

 

And what is the factory compression supposed to be also?

 

There are different comps for different year ranges. -93 was 9:1 and 94+ was 9.5:1. 9:1 I would just use a thicker head gasket but 9.5:1, IDK for any real boost I think someone should shave or spring for pistons.

 

Truck is 9.3:1

 

Stock pistons have slight dish with corner valve reliefs I think, can't recall 100%. I'd suggest swapping not just to gain proper comp for boost but because stock ring lands on the kade are weak.

Edited November 28, 2009 by 72240z

[datzenmike]

OK then what is the DE's cylinder head volume?

 

I spent a whole evening at KA-t trying to find this info and it was worse than ratsun for pages and pages of crappy "I heard i was... no it's not it's... you're both wrong it's blah blah blah" :D

[72240z]

Wiseco says 46cc Mike.

 

http://www.wiseco.com/Catalogs/SportCompact/Nissan.pdf

Edited November 28, 2009 by 72240z

[datzenmike]

That's amazing! I reverse engineered the compression months ago using the known compression, B&S, piston dish, gasket thickness and deck height and came to the conclusion that the DE had a 47cc head. Wow that's really close. Problem was I couldn't verify it. Thanks. 46cc it is.

[fo0manchu]

Called it lol

Ya you could just slap a turbo on as is. You could slap a turbo on anything but how long it lasts and how much boost you can throw at it are very comp related. I personally would rather get the motor at a proper comp range so I could safely and reliably boost over 7lb and a measly(for boost) 200ish hp.

There is always someone that will argue their friend or w/e had a 10:1 and has been running 14lb for years blah blah but I have seen soooooo many n/a to turbo motors blown I don't even listen anymore lol.

 

hahah, you talking about me? :D

 

People who blow there N/A motors usually are running way to much power and they don't have a proper tune. I see people who easily blow there turbo motors as well, who simply "up the boost" without a tune. Tune, tune, tune. Thats what it comes down to. Sad to say, most people get to excited and skip the "tune" part or are just to plain lazy/dumb to read more about turbo and how to tune.

 

So to give MicroMachinery some insightful info, KA's in there N/A form turbo'd has been done time and time again. And it is already proven that with the stock comp ratio, it can handle safe boost upwards of 12lbs with a good tune. This is for everyday driving. But remember, once you go turbo you always got to keep and eye on things. Such as oil level from blow by (another reason why a lot of people blow there motors). Yes you can drop the comp ratio and get nice parts and run 15-25 lbs of boost. thats up to you. But for lower boost levels, stock ka's are totally capable of handling that. Also, lower comp ratio = less power off the line until boost kicks in.

Good luck with the engine!

[MicroMachinery]

Nice. It's good to get some input, I feel alot more confident in putting a turbo on my KA..

.. however, in the process of all this, along with sourcing parts, I'm finding that it STILL might be less expensive just to get an SR and go that route instead.. I can pick up an s14 blacktop with everything but the wiring harness for around 1200.. I've been looking up prices on turbos, and inexpensive ones go for around half that.. and that isn't including a retuned ecm, injectors, and all the other stuff I'd have to get to go legit turbo on my KA24DE.. tough choices.. :rolleyes:

 

Thanks again, you guys rock.

[72240z]

I meant "called it" that someone would say otherwise ya lol, but not specifically calling you out or anything like that.

 

With a tune you can do a lot no doubt about that, BUT when you run boost with stock high comp on a n/a motor esp on a KA with weak ring lands you walk a fine line. The one time your motor gets out of tune, and that does happen, will be the time that motor fails. So it's always my advice and rule of thumb to boost at a proper comp for the piston/head/psi run.

 

It also sets a very low ceiling. Boost is addictive, to everyone who ever ran it with a clue on how to up it lol. So to get up and running all stock with a ceiling of such low boost and low hp to me is yet another reason to just shell out for basic internals, ESP on a motor already in pieces. At that point it's just lazy or cheap not to imho.

 

Thats my take anyway based on reading and the experiences of people blowing their shit up the one time they lean out or det on a abnormally hot day.

[72240z]

It will NEVER be cheaper sr vs ka hp:$. Yes it may be cheaper to buy a complete sr retail then to build a proper ka-t but those 2 options are not equivalent. Your built ka for the same price or slightly lower/higher (part sourcing skills) you will be able to put out much more hp then the stock 180-220 you'd be getting from a sr. With better internals, .4 more displacement, local parts sources and higher potential for growth.

[MicroMachinery]

It will NEVER be cheaper sr vs ka hp:$. Yes it may be cheaper to buy a complete sr retail then to build a proper ka-t but those 2 options are not equivalent. Your built ka for the same price or slightly lower/higher (part sourcing skills) you will be able to put out much more hp then the stock 180-220 you'd be getting from a sr. With better internals, .4 more displacement, local parts sources and higher potential for growth.

 

Hold up, hold up.

Perhaps my part sourcing skills are a bit lacking, but I'm not seeing how buying a $500 set of low compression pistons and a $700 set of rods(just for starters, mind you) is going to be cheaper than a $1200 setup that is already good(from what I've read) up to around 400hp?

I say just for starters, because I haven't seen them giving away turbos, either. Or any of the other necessary components(BOVs, Tuned ECU, Injectors, Manifolds, etc..), for that matter. I see turbos ranging anywhere from $150(VERY questionable), to $1350+. I must be missing something, or I bet it's that I just don't know the right people.

Don't get me wrong, I'm not trying piss on anybody's Cheerios, but I'm just not seeing how I could build a built turbo KA for less than twice what an already built SR would cost.. if what you're saying is true..

..enlightenment if you don't mind? Thanks.

[yellowdatsun]

Gotta agree with the parts issue, KA parts are *always* going to be easier to find, and as a result, cheaper. Plus, when the SR20 falls out of favor someday, which it undoubtedly will, parts will again become very hard to come by. Just like the FJ20 was cool 10 years ago, parts are now impossible to find. Since the KA was sold in huge numbers in our home market, it will always be easy to find things here.

 

You should be able to get a good turbo for between $350-$400.

 

Look at the guys running the SR20's, almost none of them leave them alone. They end up buying injectors, ECU's, piggyback modules, different turbo's, and then start building the motors up *anyways*. All the crap you'd end up buying. Nobody buys an SR and leaves everything stock. So since the SR20 was more initial cost than the KA, in the end they are dumping a PILE of money into those engines. That's how you can spend less total, and have a better engine with the built KA24.

[72240z]

Hold up, hold up.

Perhaps my part sourcing skills are a bit lacking, but I'm not seeing how buying a $500 set of low compression pistons and a $700 set of rods(just for starters, mind you) is going to be cheaper than a $1200 setup that is already good(from what I've read) up to around 400hp?

I say just for starters, because I haven't seen them giving away turbos, either. Or any of the other necessary components(BOVs, Tuned ECU, Injectors, Manifolds, etc..), for that matter. I see turbos ranging anywhere from $150(VERY questionable), to $1350+. I must be missing something, or I bet it's that I just don't know the right people.

Don't get me wrong, I'm not trying piss on anybody's Cheerios, but I'm just not seeing how I could build a built turbo KA for less than twice what an already built SR would cost.. if what you're saying is true..

..enlightenment if you don't mind? Thanks.

 

They are lacking indeed if your using retail prices for pistons and rods. Also at 1200 your getting a 180-200hp red top with a t25 so your going to have to pay out the ass for taxed sr parts to up that hp past 220ish unless you want to run the turbo well out of its efficiency range and blow it, not to mention fuel. Where as the comparably priced ka-t would already be passed it with room to grow.

 

I have seen wisecos, je's and eagle rods sell on silvia and ka-t etc for half their retail, brand new. The internet is filled with people selling off parts to incomplete dreams. Not sr's though lol. I'm not going to go down the list part by part because the build has been done soooooo many times, the numbers are all over the place if you don't believe me or need the proof.

 

I take no offense every time the sr vs ka-t convo comes up there is a disbeliever, but they are YOUR cheerios, I already have friends running the ka-t so.....

Edited November 28, 2009 by 72240z

[MicroMachinery]

Yeah, my Cheerios got piss in em. Thanks though man, you're seriously giving me legit food for thought.. NOT pissed-in food for thought, I might add.

[72240z]

lol ya I mean you should challenge, it's healthy but I can't type the book to prove it all. Check it out on the other forums, people have full build threads with goals and costs laid out. It's worth looking into for sure, if for no other reason but to know all your options.

[MicroMachinery]

Yeah, since this thread was born I've been reading on ka-t.org. Never knew about it before.. guess I was a little more passive about the whole idea until pretty recently. I thought I was gonna be A-OK with N/A until I really started thinking about it.

And yeah, I don't expect to be spoon fed. Searching for the info and discovering it for myself is half the fun. I was reading a guy's "build("SPEND" is more like it)" last night that didn't even care, he just had piles of money to throw at his Datsun, hired mechanics to do all the work.. made me sick. No appreciation, probably never even picked up a wrench. Gutted everything stock out of the 72 Bluebird RHD and just tossed it in the trash to make room for a high dollar makeover. Puke.

[datzenmike]

Nothing wrong with stock compression and turbo. You just have to keep an eye on pre-ignition by alcohol/water injection, inter-cooler, ignition retard, proper enrichment during boost and engine temp by cooling system and oil cooler. Forged pistons will survive pre-ignition forces better than the stock hyper-eutectic ones. During non-boost times, (which is 99.9% of the time) a 7 to 1 motor drives just like a 7 to 1 motor. A stock compression motor will make more power sooner and bring on the boost sooner.

[Drahzzel]

One of the biggest questions you need to ask yourself is, realistically, what is your goal for the car? Is there a target horsepower number you want to achieve, or are you looking for power within a certain rpm range? If you're only looking to make 250hp or less, the stock internals on a KA motor will suffice, but I do recommend getting either an aftermarket fuel/spark module or some kind of piggyback module such as Nistune and a wideband O2 sensor then having it tuned properly as has been mentioned before.

[MicroMachinery]

One of the biggest questions you need to ask yourself is, realistically, what is your goal for the car? Is there a target horsepower number you want to achieve, or are you looking for power within a certain rpm range? If you're only looking to make 250hp or less, the stock internals on a KA motor will suffice, but I do recommend getting either an aftermarket fuel/spark module or some kind of piggyback module such as Nistune and a wideband O2 sensor then having it tuned properly as has been mentioned before.

 

At this point in time, I am looking for less than 300whp. In fact, that is probably way more than I actually want. I think I'd be tickled pink to have 250horses, with equal/greater torque. Again, the thought of 130whp just doesn't get me all that excited. Sure, it's a HUGE improvement from the 60-something stock L16, but it just doesn't seem like I'd be satisfied.. I just want to make sure that I'm building something that will keep me happy. I don't want to be bored of it in 4 months, but I also don't want to be forced to sell it due to run-ins with Johnny Law. I think 180-250hp is where I want to stay. No more.

[72240z]

During non-boost times, (which is 99.9% of the time) a 7 to 1 motor drives just like a 7 to 1 motor.

 

That some silly stuff to say mike lol. Anyone who drives a turbo car and is only in boost .1% of the time shouldn't own one.

[Skib]

That some silly stuff to say mike lol. Anyone who drives a turbo car and is only in boost .1% of the time shouldn't own one.

 

cruising along and hammering it to full boost never gets old :cool: never

[MicroMachinery]

cruising along and hammering it to full boost never gets old :cool: never

 

Damn.. I can't wait.:D

[72240z]

cruising along and hammering it to full boost never gets old :cool: never

 

Its the truth, IDK how anyone could resist it. I miss my z32's from time to time but what it really comes down to was flooring that TT. Is the whole reason I chose l28et for the s30 ::taping my arm:: I NEED IT BACK!!!! lol

[datzenmike]

Oh absolutely! But you can't boost all the time. I'm thinking of the drive home in traffic, stop and go, idling at lights, warming it up, cruising in traffic... it all adds up. Those few short seconds of go erase the boring stuff in between but lets say 95% of the time.