Adding a second bank of injectors

[iceminion]

We are just about ready to install megasquirt on Mugs 2.4/GT35R street car.

I only want to make the wiring harness once, so I figure I may as well take full advantage of the megasquirt platform and "add everything" right now, even if we are not using the features currently.

Megasquirt has a feature which allows for dynamic timing and fuel table adjustments depending on how much ethanol you have in your tank at any given time

We bought 1000cc/min injectors, but after thinking about it for a while and doing some calculations they just might not be big enough.

Although COMBINED with the stock 450cc/min injectors we would have enough!

Megasquirt has this neat feature where you can use a second bank of injectors.

I am not 100% sure how it works, but as far as I can figure it activates the second bank as soon as you pass a pre-determined threshold for the first set.

so, in this perfect world, the IDC of the first set of injectors increases until it hits a safe limit, say ~80% then the second bank activates and the first bank kicks down to about ~20%. and then both banks ramp up accordingly.

Advantages:
-better idle because I can use the stock 450's and have the 1000's switched off
-not be limited in the future, it would be easy to buy two sets of 1600's if i ever wanted to go crazy and make mad HP

My question is: What is the best way to go about adding the second bank of injectors?

The fuel and plumbing is pretty easy to to, im not too worried about that.

we have this for the intake manifold:
http://www.roadraceengineering.com/p...e_manifold.jpg

I assume it would be easy to weld four injector bungs and rail mounts on this bad boy.

where do I buy the bungs?
who could weld me up something like this?

I guess i am going to have to weld them on top, we have AC in this car, along with mounting the cruise control under the manifold.

So much for a clean engine bay!

[Goat Blower]

What do you have for a manifold currently? I have a Venom SMIM already set up for eight injectors, I'm only going to use four since I found out my 1600's were enough. So in essence, if you've got something nice, I might be up for a trade. I've got mine set up with -6an lines with nice v-block splitters as well for a bit extra.

[iceminion]

As listed in my post

http://www.roadraceengineering.com/p...e_manifold.jpg

would love to see pics of yours

[Goat Blower]

What throttle body is yours flanged for? I forgot mine's set up for a Ford style throttle body and I don't want to change back to a stocker quite yet. Here's some pics.

[iceminion]

We brought the manifold to M&L welding in saint cloud, (1st exit into saint cloud, down a mile, on the right) and after some sweet talking, we got them to fab up the bungs and rail mount, and weld it all up.

Here are the pictures, they were very professional and charged a hefty (but fair) $190.

Now that the easy part is done, we gotta start figuring out how MegaSquirt is gonna control the 8 injectors!

[Goat Blower]

Looks great, and $190 sure ain't bad for that kind of fab work and roll of coins welding.

[Swifty1638]

ice, if you REALLY want I got a set of 1600's..bout 22 miles on them..that's it. I'm never doing e85..and my setup would be fine with 1000cc's. as long as yours are new, i'd be willing to do a trade..call/text my cell..763-226-6458. tuning the car at idle with these things is semi difficult..but if I dont get rid of them..i'll still run them.

-A. Swift

[95talonracer]

Why didnt you just go with some 1600's? I have herd that some people have troubles idling with them but I have them on my car and have not had one problem at all and they run like my old 880's. I am running dsmlink tho so maybe it is the megasquirt that would be the issue with idle.

[iceminion]

From what I have been reading, megasquirt2 has a factor of 10x times greater injector control then our ECU's (read: it can control whatever I throw at it)

On a car like this, who cares? its a daily driver, having a nice idle is desirable, so the stock 450cc's will work for this.

we were planning on just running the 1000cc's, but now we can use any combination of injectors we want. besides it looks awesome.

[Goat Blower]

Yeah, I got my 1600's to idle better with the AEM. DSMlink seems to be a little tougher to get these dialed in, but with the mods I'm doing to the throttle body today and the E85, I should get these to idle really nice.

[Andrew7dg]

To do the second set of injectors,
wire the first (primary) injectors into the first injector bank of the MS2. There are two wires for the 1st bank. You will have to combine wires to make them work. Combine injector 1&2 on one wire and 3&4 on the other wire. Injector bank one will control these 4 primary injectors.

Do the same for the second rail exept use the two wires for injector bank 2

When tuning, you are first just going to tune on the first bank. Then when you start running lean (most likely when you are hitting boost) you run the second bank of injectors.

I highly recomend starting out the tuning (or just trying to get the car started, which is going to be difficult enough) on the first rail. Just get a good tune on that.

Also make sure that you have all the settings correct in the MS. Also figure out if you are going to be using the resistor back or not. MS can handle it in both ways but you must make sure to have the correct base settings.

as for controlling bigger injectors, MS2 has fuel control to 1 µsec, which I think is a little faster then the stock ECU I believe