Starting to tune on Alpha-N

[das e30]

Hello,


I am in the process of building a e30 with a SBF 302 in it. The motor is completely stock '87. I am trading my M20 for this motor since I figured it would be a lot easier and cheaper to get power out of this motor than an M20, and the mix of a my favorite car and good old American V8 makes me put a smile on my face, and at 18 years old living on my own I don't have the big bucks to spend on a built turbo m20.

The motor is completely stock as of right now, but it comes with no intake manifold. What I'd like to do is create a ITB setup for it with two sets of Hayabusa throttle bodies, not so much for performance but for the sake of it being cool and a challenge that I'm willing to take.

I've been researching on how to tune Megasquirt and how to tune ECUs in general for about year and a half now, so I have the basics down just need to set my foot down and start getting practice in.

Since I'm just starting and I don't want to go in over my head with this. The motor will retain a distributor and a MSD ignition system. I want to use Megasquirt for fuel only for now, since it's a lot easier to tune it on the street. From what I've noticed you need a dyno to tune ignition maps (or at least to get optimal timing), and I just don't feel comfortable tuning that. Yet.

Now my question is, is asking to tune for the first time on Alpha-N too much? From what I understand Alpha-N uses engine/IAT temperature, TPS and RPM to calculate fuel. I really do not see how hard it would be to tune it while someone else drives. I will also be using a datalogger and a WBO2 (not an option). Also how is the drivability on Alpha-N? This car is going to primarily on the street, and occasional dragstrip use (once a month or so). This will not be a daily, so I'm not really worried about gas, but I don't want to go with a carburetor and spend $100 in gas to cruise on a weekend or worry about swapping jets because it's a bit chilly tonight.

The reason why I want to go with Alpha-N is because sometime down the road I'll be swapping the heads and the cam for something bigger, and from what I understand with a big cam you can't get a solid vacuum reading at idle.


So what do you guys think? I have zero experience tuning any time of fuel/ignition (carburetors, distributors, Jetronic), but I can comfortably say I am a decent mechanic and I have a decent amount of experience diagnosing cars, especially since I work at a German-car only mechanic shop.

Any help/opinions would be GREATLY appreciated, and thanks for making a standalone that is budget friendly, and people like me can enjoy and learn.

Oh and I do enjoy looking at people criticize my ideas.
Haters gonna hate after all ;)

[.boB]

Alpha-N means (as you know) RPM and TPS. Based on those two inputs the computer will use a table/map and provide the proper injection squirt.

The tables can be modified by things like intake temp, coolant temp, baro, manifold vacuum, etc. But the basic fuel charge is provided by the map.

My current engine runs on Alpha-N (via Haltech F10), and some modifiers. It runs great, makes excellent power, and gets good gas mileage. On a steady highway cruise I get about 20mpg.

Tuning is relativly simple. It's easier on a dyno, but can be done on the road with a wide band; I use the LM-1. Once you get the basic tune in, then you add the modifiers for things like altitude changes, hot/cold weather, etc. My Haltech is pretty old, and doesn't have any self learning modes. Should be real easy with MS-II and TunerStudio.

I currently use a Mallory Unilite with a Crane Hi-6 ignition box. One of my main reasons for using a MS-II is to get rid of the distributer and box, and have the computer control the ignition via wasted spark coil pack. There are a lot of advantages to that, even on a stock SBF. Cost is about the same for both set ups, but the MS-II is a little easier. And it's certainly more flexible.

You do not need a a dyno to tune the ignition. To get every last hp out of the engine, a dyno will really help. But it's less important for the ignition than it is for the fuel map. With a stand alone ignition system, you'll be setting a curve based on driving feel alone, and no dyno time. But you'll need to take the distributer apart to change weights, springs, and stops. And available adjustments are somewhat limited. With computer control, you just tap a few keys and change anything you want. You can easily add a more flexible and usable vacuum advance curve, and add a retard for engine knock.

I cannot see any good reason to use a stand alone distributer instead of computer control.

[firefoxx04]

not to discourage you (me being 18 as well ) but ITBs on a v8 will have a touchy throttle and might not be nice to drive on the street. with that said, go for it!

tuning with alpha n should be easy. once you get the car to start you just have easy stuff left. tune the idle by adding fuel or removing fuel and then do the same while free reving. then take it for a cruise and get the cruise figured out.. then start doing part throttle pulls and eventually wide open pulls

if your ign is already squared away, then you have most of the battle done already.

[.boB]

not to discourage you (me being 18 as well ) but ITBs on a v8 will have a touchy throttle and might not be nice to drive on the street.

Not true at all. ITB's create a very flat and predictable torque curve. Once they're tuned properly, they are a reall joy to drive.

The big trick to getting them tuned is the proper balance. You need to spend a lot of time designing and fabbing the linkage, and then use a good synchrometer and get them all spot on. It's a tedious and time consuming process. Once done, tuning is a breeze.

[lukep6470]

I am doing almost exactly the same setup on a 289. I've just about completed the manifold using 46mm Mikuni throttlebodies. The throttlebodies are mounted and I'm just finisthing off the linkages, sensor, and vacuum fittings.

I've bought a Microsquirt and Ford hotrod harness with the adapter cable for the microsquirt. I'll be doing fuel only to start with and using a Ford rebadged MSD 6T on a duraspark II distributor.