Recommended engine tuning for the J13?

[timmy]

Hey there,

   

     I'm a bit new to this party and apologies if this has been discussed before, but I'm wondering what would be the best tuning options to give my little truck a bit more power and better sound. I see that some folk are fitting MGB manifolds and sidedraft Webers to their engines but I'm wondering whether it's worth it over the stock Nikki.... Any suggestions?

 

Also, what is the suggested exhaust size for this engine? Would 2" be about right?

 

Cheers,

 

Tim

 

 

[datzenmike]

Two inch would be way too big. What ever is on there now and add 1/8" or just leave. Get a lower restriction 'turbo' style muffler but not one of those straight through things. This will give you a better sound.

 

If you go with a side draft(s) you really would need a better cam to make use of it.

 

A small displacement engine can make more power but it has to rev up to do so and there's little change in the range where you drive it 99% of the time. For this a larger displacement does the trick. Larger displacement makes more torque at lower speeds. Any chance of finding an L20B and transmission?
 

[bananahamuck]

If your looking for a better sound i saw a guy ( on the internet ) use a MGB exhaust manifold which has 2 outlets in it,,, If ran separately you could probably get a very unique (badass)  exhaust note.

 

Here is his blog on car domain ,, you have to click the goofy orange "more" words to see anything which kinda sucks

 

 

http://www.cardomain.com/ride/534452/1966-datsun-410/

 

 

Clickity- clickity ^^^ 

[datsunrides]

I have a 2" exhaust on my J13, but that was just because I had some tubing and mandrel bends around. I wanted it fairly quiet so I have a glasspack and turbo type muffler. Realistically, 1 1/2" is fine for what this engine is capably of putting out short of forced induction or serious engine mods (like a crossflow head, big cam, etc. Even then........) A new 1 1/2" exhaust in itself may help out if the old one is on poor shape. For sound, try just a glasspack with the louvers going with the flow. Too loud?, flip it so the louvers face the flow. You could also try a resonated tip also. Another  option would be a mini turbo muffler. Would be somewhat quieter than a glasspack, depending on the length on the glasspack. You can also buy a header  to replace the stock exhaust, but is is not a bolt on affair and you can't run the stock intake with the header.  As for the MGB intake options? Not much to gain there without a cam and or headwork. I have a single sidedraft weber on mine and it does have somewhat more power than the stock carb, but is it worth the cost? Note the weber is running 28mm chokes! I did it more for the looks than any substantial gains. If your carb is in good nick, keep it. If it is buggered, maybe a 32/36 will work if it is jetted down. In the end, if you want a big jump in power from a J13, be prepared to spend some coin, or better yet, spend that coin to swap to either an A series (fairly easy and way better parts availability) or a L series (will take a little shoehorning in a 520) Since you are down under, a CA18 may also be the ticket as they are pretty compact and way more modern then the A or L series, but probably the most work. I know if I could get a CA here for cheap, I probably would have put one in my 520.

 

Mark

[XXL]

what would be the best tuning options to give my little truck a bit more power and better sound. I see that some folk are fitting MGB manifolds and sidedraft Webers to their engines but I'm wondering whether it's worth it over the stock Nikki.... Any suggestions?

 

Also, what is the suggested exhaust size for this engine? Would 2" be about right?

 

You need to stick with 1.5" diameter.  Going too big will reduce the exhaust gas exit velocity too much, and so they don't scavenge as well (creating backpressure-- the very problem you though you were solving with a larger diameter).  

 

As for performance tuning the J13... I think you're starting with the wrong platform if you're serious about any meaningful performance gains.  There are a couple of A-series supercharger setups that could be made to work fairly easily, but you're going to spend $4-5k US to do it.  Maybe an engine swap is a more effective way to get the 25-30hp that supercharger will bring.  

 

Or... just drive it and enjoy it as it is.  It's a pig.  Everyone knows it.  But it will run like that forever, and it makes a great conversation starter... my standard line after someone comments on the truck is, "but don't get behind me on a hill."

 

And pics.