I really need some direction from someone that knows more than me, NA KA.

[Z Style]

Okay, I have tapped my buddies out of info. I have a KA24DE that I am building up, it is already torn apart and is going to the machine shop soon. I am getting it bored out, but the machine guy also brought up compression. At first I just wanted to run pump gas, because I have a CA18DE I was going to build up in the future, but now I am thinking about going all out NA. I am on an extremely tight budget and just want to get the machining and the internals done for now. Later I wish to install a different cam and cam gears.

Okay with that said; if it is possible I am going to install bigger valves, bore out the engine, and run a pretty large compression. I plan on mixing 93 octane pump gas with toluene to get the octane up to around 98, so basically my compression will be built around those paramaters. I have an OBX header and I am going to run 2.5 inch exhaust to one of those open canister style mufflers that is alost 2.5. My main issue right now in all this figuring is tuning, at first I was going to attempt to just run the stock ecu and see if it will run for a while until I save money for a Greddy Emanage or something. Then my friend brought up the idea of him running Megasquirt on his KA-T. I talked to my buddy that built up a raised compression engine using the SOHC pistons in the DOHC block, he had them machined down some, and the compression wasn't all that wild. He shot down my dream of using the stock ecu and he said with Megasquirt the only real problem is there is no base map to start from.

That is all the info I have of right now, so you guys know my dream. Is there anyone out there that has used Megasquirt and that has something I could start with or do you guys think I should take a whole different route?

Any help would be greatly appreciated!

[250sx]

I dont think you can get to 94 octane with any kind of toluene mixture. maybe tinting super unleaded with race gas. btw, lead is supposed to be bad for oxy sensors.

[eddiec]

if thats what you want then do it. megasquirt has been done to a ka. several people here already use it. but bewware it is Very diy intensive.

i plan on bumping compression with some late model 'e' pistons. that, itb's and MS w/EDIS is my plan.

[Z Style]

I dont think you can get to 94 octane with any kind of toluene mixture. maybe tinting super unleaded with race gas. btw, lead is supposed to be bad for oxy sensors.

There is no lead in anything that I would be putting in my engine. Toluene is an octane booster, it has an octane rating of 114. The old turbo F1 cars used to use like 87 percent toluene and the rest was filler to bring down the octane rating down to 102 to coincide with the rules.

[Z Style]

if thats what you want then do it. megasquirt has been done to a ka. several people here already use it. but bewware it is Very diy intensive.

i plan on bumping compression with some late model 'e' pistons. that, itb's and MS w/EDIS is my plan.

That makes me happy to hear that some people have used the Megasquirt on the KA, thanks.

[250sx]

Are you talking about toluene at the hardware store? I just mentioned lead because I think all race gas has lead. correct me if im wrong. Let us know how you did the megasqrt if you use it.

[Z Style]

Are you talking about toluene at the hardware store? I just mentioned lead because I think all race gas has lead. correct me if im wrong. Let us know how you did the megasqrt if you use it.

Yes, the toluene that they use as a solvent. You can get it from chemical supply companies, paint stores, and I guess hardware stores also. I am going to see what kind of bulk supply I can get it in. I do know you can get race gas in unleaded also. I will be sure to keep you guys informed about the Megasquirt, my buddy is also planning on running it on his KA-T so I will make him post up his also.

[deviousKA]

toluene/xylene cost around 8 dollars per gallon in gallon sized jugs, if you can find a supplier for 55 gallon barrel you can get it as cheap as 3 per gallon.

I run megasquirt based system in my fastback 240sx, if anyone would like the info on wiring using oem fuse/relay box let me know, it works out rather slick after a few small modifications. The rest of the harness of mine is all custom made. Other peoples basemaps are not going to yeild same results on your engine, to many variables with sensors etc... Its not hard to set one up for your particular needs anyways.

[Z Style]

Hmm, interesting. You sound like you know a lot, would you mind emailing me the diagram and what all you used to run Megasquirt on your car?

[email protected]

[deviousKA]

ill put together some diagrams and possible parts lists here in a few days when i find some time to retrace my entire harness and write it all down. Ill post it here. On my setup i used some GM and suzuki sensors although i could list up some temperature/resistance tables for the nissan oem temp sensors (mainly coolant) as well. I did this on a sohc harness car and used a portion of the oem harness patched into my custom one.

[Z Style]

I have an auto SOHC harness and should be getting my DOHC harness soon. One of my main concerns is the parts you need besides all the stuff Megasquirt provides you and from what I have been reading it doesn't sound like you can use the KA sensors.

[deviousKA]

You can make nissan temperature sensors work, or any other thermistor type sensors for that matter, all that is needed is new reference files flashed to the MS ecu. This is really simple using easytherm found in the msefi download section, look it up for more explanation. Tps will work as well, you just calibrate the adc count during your wiring setup. The standard temp sensors used for megasquirt are gm sensors, these use 3/8 pipe thread, which is much to large mainly for the coolant temp on ka upper water neck. On mine i used a suzuki motorcyle air temp sensor for coolant temp, simply because the connector was nicer and thread is same as the nissan. Most toyota sensors are also same thread and will spin right in. Air temp sensor can be mounted different ways and the gm 3/8 thread version is not so big of a deal, thats what im using.

Im not sure if nissan 240sx air box temperature sensors (like on late sohc models) will work, never really looked into it.

Nissan standard single wire o2 sensor will feed the ms the proper enough signal, narrow band accomplish little anyways and wideband should be used for tuning.

You should use the auto sohc fuse box/lower engine harness since you already have it. You can source all of the relays from the connectors that are next to the battery (brown 8 pin, grey larger 8 pin they are next to each other), also the speed sensor wire for speedo needs to be patched in at this location. The ecu/injector power relay is a "dual enabling" type, it needs to be modified in the fuse box to operate with one wire off the ignition switch. The fuel pump relay is controlled with one wire and is easily interfaced to MS. All of the starter motor, oil pressure sensor/transmission harness can stay intact, patching in what you need at the connector i mentioned above. I also used the oem ignition power, for power to my edis system, this is not relayed but direct from ignition switch.

Thats probably a bit much to understand at one time, but you should be studying the megasquirt wiring diagrams (for making custom harness, non relay board) to get an idea of what all you will need. The fsm engine harness schematics are also a huge help.

Before you go any further you should decide on what ignition system you want to use, and verify that it will operate properly with MS. You can run a modified distributor, or various types of wasted spark distributorless systems, or a combination of both. Check out the msefi megasquirt&spark sections, or ms&edis.

[PandaS14]

I will be running MS on my n/a ka in the near future too. Ordered it a while ago, just waiting for it to get here so I can start putting it together.
Modified by PandaS14 at 11:57 PM 1/21/2005