Hello

My Setup:

Tweakit 50mm Throttle bodies
Bridgeported 13b S4 (turbo motor without turbo)
4x550cc High Impedance s4 Turbo injectors
Megasquirt 2, V3

The whole setup is in, megasquirt is assembled and im almost done wiring it all up. I am only going t control fueling with the MS and use a distributor for spark.

The main question I have is should I run Alpha-N? Im thinking that with the large overlap of the bridgeport along with the Individual Throttle bodies that the map reading will be to low and/or fluctuate too much to work well enough for my setup. Im open to suggestions I just want to go the route which will give me the most out of my setup, any advice on any aspect of my setup would be appreciated and I will give more info if needed.

Thanks

 

I would run alpha-n with that setup, or some sort of hybrid alpha-n/speed density at least.

Ken

 

Ok thanks, I also need a little help with this wiring. I need to know where the Fuel pump relay, main relay and ignition switch are, can anyone help? I cant find an easy way to distinguish between them.

 

Sorry, that wasnt very specific im just very used to posting on the first gen forums. I have a 1985 first gen rx-7 which had a 12a. Ill ask in the first gen forum rather.

 

Hi, I'm struggling to tune my 13b bridgeport at the moment.
I'm running pretty much exactly the same setup as this.

I've attempted tuning with alpha-n but I don't quite understand how it knows to compensate for load?

As Ken mentioned, its possible to run a speed density/alpha-N hybrid type tune. How is this possible? I've been trawling the net looking for how I might do this but can't figure it out.
Do I use the percent baro setting in the control algorithm option?
How will a VE table work for such a setup, do I need 2 VE tables? one for Alpha-N and one for Speed density?

I'm very lost, can someone please shed some light on the matter. Thanks!

 

You will use your own "main" relay and fuel pump relay when you wire up the Megasquirt, there is no need to use 20+ year old stock junk. Grab a set of good relays and holders from the auto parts store and wire them up according to the Megasquirt wiring diagram.

Pull your 12V IGN signal from the ignition switch on the steering column. I think in a 1st gen it is the black/white wire, but check with a meter first. You need to find a wire that is at 12V when the key is at start and run, with no interruption between those two positions. This signal is just used to trigger the main relay for the Megasquirt.

 

There is a good howto on the hybrid setup with ITBs here:

http://www.77e21.info/mstuning.htm

Ken