Reliability Issues

[jhoot]

Its prob. been discussed before, but the search function isn't working, so sorry if i post about it again, but i was wondering about reliability issues with either the SR or KA-T.  If i was to go KA-T i would get 8.5:1 pistons and a JWT ECU upgrade (heard that this was the best way to go)  and have it professionally tuned and installed.  with the SR I would go with an redtop put an s15 turbo on it and turn up the boost (also would be professionally done).  Over the long run which engine choice  would be more reliable?

[sykikchimp]

Well, if you put pistons in the KA it should last just as long or longer than the SR.  Given both motors start with the same # of miles they should last fairly close in life span

[Kitahara]

It depends on a couple things: what is your target for power output, and can you handle waiting for parts to come from Japan if something breaks.  

The SR is obviously designed to handle boost very well, because after all it is a turbo motor.  Some people say that the SR is good for 450hp before reliability becomes an issue.  I would play it safe and def. not push past lets say 400hp on a stock SR20, this is ofcourse assuming you would have sufficient fuel supply & mgmt first.  Again the problem is that if anything brakes i.e. oil pump, ignitor etc. you would need to import the parts and that could put you out of business for atleast a couple weeks.  

IMO, I think it is far more worth it to go with the KA motor for several reasons.  1. Domestic parts are cheaper and easier to find = no down time.  2.  The KA block is iron which means that it is quite reliable. 3. 2.4ltr, and pleasant rod/stroke ratio 4. Cheap!

My suggestion for the KA would be 8.0-8.5/1 cr pistons and a copper head gasket to start.  That should suffice for some decent turbo performance.  However, while stock cams make for a 1/2decent turbo application, there are significant power losses shortly after 6k rpms.  If you could increase the rev-ability of the engine while making the power curve more progressive throughout, you would have a greater power band for boosting ( a lot more like the SR20).  To do this I would spec out custom made cams for turbo application and good progressive power curves between 3-8k rpm.  Although, to get to 7.5k+ rpms effectively you may need some headwork in addition.

Well, that's just my idea, I am debating the same issue that you are as well. &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/hehe.gif" border="0" valign="absmiddle" alt=':hehe:'>

[drift freaq]

touchy issue &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/hehe.gif" border="0" valign="absmiddle" alt=':hehe:'>
SR folks have their opinions and KA folks have theirs.
I will give what I know from my research.
Stock KA's done right with the fuel setup can handle 300hp on stock internals without breaking a sweat.
the weakest link would have to be the cast pistons though the do come stock with oil squirters(hey thats a Turbo setup <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/hehe.gif" border="0" valign="absmiddle" alt=':hehe:'> )
Now on the cams if you use 91 cams you will have power beyond 6K but the meat of your power is still going to below that. Also if you use a repinned 91 exhaust cam on intake ala T.Y.'s setup you should get quite a bit of power and still retain decent gas mileage.
KA's are very much turbo type engines even though they never were Turbo'ed . Like I said earlier the piston is the only thing you really need to change if you want to push high boost. A good set of forged pistons with total seal rings should take care of that.
As far as breathing goes we are talking forced induction here . Porting does not really matter. Of course larger downpipe will help but thats exhaust.
I do not recommend lowering compression for one reason . Stock compression is still within boost parameters for Turbo setups and it will eliminate any kind of lag you would experience with lower compression pistons when you are off boost.
Unless you are making this thing a 500hp strip monster stay with stock compression ratio's and you will be happier for it.

[MyFirst240SX]

if u get forged pistons and ring set do u need special connecting rods and push rods?

[crazycuban]

It really just depends on how you do it. &nbsp;You can make a very reliable SR, or a very reliable KA. &nbsp;You can make a shit SR, you can make a shit KA. &nbsp;Unless you're trying to build a sub-10 second drag car, and every ounce of reliability you can eek out of an engine matters, you'll be fine with either. &nbsp;It is easier to get KA parts, but SR's can go higher on stock fuel setups, and theoretically I've heard that SR's can handle around 450, with only a cam change, and then after that building the motor. &nbsp;Have the right fuel setup, the right boost settings, the right cooling system, the right internals, and you'll be straight with either one.

[Fresh 240SX]

Lets put it this way..... with all other factors aside... if you go KA-T you are safer in terms of parts and whole engines available should you need to repace something... If you wreck an SR its not like you can go to any junk yard and say... Got any SR20DET's layin around? So there could be some added down time with the SR in terms of the fact that there are not so many around (ones that arent in use for that matter) not to mention the price, Supply & Demand PPL!
Your safest bet if reliability is a issue would to go KA-T....
Keep in mind the SR is built for turbo from the factory, they are both strong and reliable nissan products, to each there own

Not to take anything away from either engine or whip the proverbial dead horse and restart this SR Vs KA thread but i persoanlly do not have enough cash to order replacement parts for a SR if i was to mess it up.. not saying it would, but anything can... i would rather take the safe route and go KA-T and enjoy my car rather than fear the downtime of SR repairs..

Besides the KA is a bigger engine... <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'>