Port Fuel Injection for a 360 - Mopar Tech

MrN2OBelvedere · #1 10-27-2008, 10:11 PM

Hello All!

As you may know from previous posts, I'm working on doing an EFI conversion for my 360 powered 1967 Belvedere. Although this will be focused on the small block conversion, the information here will apply to anybody wanting to convert their combustion engine to fuel injection.

Let me give a little background for myself. I went to Georiga Institute of Technology to get a degree in Mechanical Engineering, and my passion is in automobiles. While I was there I joined a team called GT Motorsports (http://www.gtms.gatech.edu/). The object of this team was to build a car from scratch to compete in design, autocross, and skidpad events. These cars are seriously fast. They typically employ high end motorcycle engines, and weigh in under 500 lbs. The car we built had 1.2g+ engine acceleration and 2g+ in braking/cornering. Of course we bought what we could, but for the most part, the car was designed and built from scratch, including the chassis/wheels/suspension/intake systems/bodywork/brakes...as much as possible. I was the powertrain leader while I was there (not a very successful PT engineer :P), and during my tenure, I learned quite a lot about intake and exhaust systems, and also a good bit about cooling systems. It really was the stuff of dreams...we made stuff from scratch using carbon fiber like it was scrap metal. At any rate, this ties into this post because the car employed a custom EFI system, and I had a great deal of experience tuning this car using the system that we had (a pricey motech m800 ecu and a custom carbon fiber intake that we designed).

My Plymouth will be much more modest (as is my budget...I don't have 100K to spend on a toy race car!). My goals for this project:

fully adjustable fuel injection/ignition control system for under $1500. It could easily be done for less than that but I'm picky about certain things (I'll get into that later).

System must have upgrade potential (turbochargers anyone?)

I want to be able to start the car, on a cold winter day, with no fuss. Honda Civic style no-fuss.

The system must fit under the stock hood. I don't want a scoop. If I had a Hemi or a really rad 440 I might consider a six-pack style scoop like the silver bullet gtx but, well, I have a small block.

Increased mpg would be a nice bonus...but it's not a primary concern.

Instead of using the latest greatest megabucks fuel injection kit I'm going to employ the Megasquirt (www.msefi.com) for my controller. The plus side is that it costs about $250 for the controller...the downside is that you have to assemble everything yourself (As we speak I'm finding this to be not terribly difficult). If you are going to embark upon such a project you will have to learn everything there is to know about EFI systems. This system won't tune itself like the $3K+ Edelbrock system. That's the only downside. The plus side is that there really is no limitation on what combinations you can employ or how much power you can develop. You can put a megasquirt on a weed eater (hey...it might be fun!) or a 16000 rpm V-12...basically any engine that burns combustible fuel can run this system.

Let me give a few basic details of my car...

It's a heavy as hell Belvedere with a 360. I probably should have gone with a big block from the start but I'm far too invested already with the sb, and I have a borderline sick obsession with creating a fast sb powered b-body. Can it be done? I think so.
M1 single plane intake with a 750cfm carb
It has a mopar purple shaft cam...I can't remember the duration specs right off hand but it is the .474 lift hydraulic cam. It doesn't sound hot enough for my taste.
Comp anti-pump lifters
KB flat tops near zero deck yielding 10.6 compression
302 casting heads with 2.02/1.6 valves and heavy heavy porting
Eagle I-beam rods
A few other details which aren't worth mentioning.

Low end torque is non-existant...but then that wasn't my goal with the car from the start! I think the intake choice was probably not a wise one, but as you can tell at this point I'm not so worried about it.

The major parts I have acquired thus far:

Weiand Hi-Ram tunnel ram. I'll be using the lower portion of the intake for the EFI conversion, and fabricating the EFI plenum. As before, this intake isn't so much geared for low rpm torque but that is not what I'm aiming for at this point with my project.

Infinity Q45 throttle body. This is a very nice piece, and they are all over ebay for under $100. I got mine for $60 with shipping. It has a bore of about 3.5". It will flow more than enough for a NA 360 in this state of tune, or really anything naturally aspirated up to 500hp or so.

30lb/hr bosch injectors

Megasquirt MS-II EFI computer, Megasquirt Stimulator, 3bar map sensor, wiring harness

Bungs for the fuel injectors

Fuel pump (Mallory 110 gph EFI pump)

I didn't just buy parts listed above at random...I'll be going into more detail on that later.

Also, the upper plenum is in the final design phase. I decided to go with the simpler route with a centrally mounted throttle body, basically because the design I have shown in another post will be way too complicated to easily fabricate, and I doubt it would amount to much in terms of power output compared to what I have selected. I attached the image of the latest design, and as with the other parts, I'll explain more about the design later. (I had trouble with uploading this time for some reason) I'll post more pics of the parts, and as I have time (I'll be working on the Megasquirt assembly after work!), more commentary.

Stay tuned!

MYBD318 · #2 10-28-2008, 08:51 AM

I like it I like it alot. Its great your not afraid of taking on a major FI project. I will be watching your progress closely.
Mikey

RacerHog · #3 10-28-2008, 12:09 PM

Sweet...Can't wait to see this thing running.....

MrN2OBelvedere · #4 12-18-2008, 07:20 AM

After a long break I am back and have made some decent progress on the EFI conversion. Sorry I took so long to continue, but my job requires quite a bit of travel, and I have to go to SE Asia for a few weeks and also a couple of domestic trips, and quite frankly, my job takes precedence!

So at any rate I wanted to update things that I have been working on.

-Almost finished with megasquirt assembly
-Completed work on adapter plate for plenum

I have attached some pics of the new (simplified) design for the intake, one showing the plenum design and one with the plenum and TB hidden so you can see the adapter design. I also posted a couple of pics of the adapter plate I got in from the machine shop yesterday. Later on I will also upload some pics of the megasquirt assembly process and of course at some point write some of my design notes.

By the way the adapter plate cost me $100 from the local machine shop, to give you an idea of costs involved. Honestly the most expensive thing with such a project is time, and the time spent in design is considerable. I'll talk about more of the design later on.

Enjoy!

'74DartSwinger · #5 12-18-2008, 11:33 AM

i like it. keep the pics coming

MYBD318 · #6 12-18-2008, 12:17 PM

Looking good!

MrN2OBelvedere · #7 12-30-2008, 09:17 AM

Hello all.

I am trying to figure out what to do about the fuel system for this project before I blow a ton of money.

The central point at this moment for me is selecting the fuel line size. Should I go with a 1/2" supply system or a 3/8" supply system?

According to Mallory a 3/8" system is good to 500 hp and a 1/2" system is good to 700 hp. The "problem" with my situation is that I would like to eventually turbocharge this engine, which would bring the hp level from its current 350-400 level to 600+ easy.

Anybody here having success with 3/8" line and a 600+ hp engine? Should I just bite the money bullet and go with the 1/2" system?

The difference in expense won't be small; if I can get away with a 3/8" system then I can easily adapt my current fuel tank with a mancini 3/8" fuel pickup and a moroso pn 65385 fuel return adapter. This would mean little fabrication. If I need to go with a 1/2" system then I'll have to adapt a sump. Also the fittings/filters/etc for the 1/2" system will be quite a bit more expensive. However, I'd much rather spend the money once and not have to rework anything.

I appreciate all of your input guys!

RacerHog · #8 12-30-2008, 09:29 AM

Inlet #8
Return #6 if your going to us return
Use a good Pump and regulator...

just my 2 cents

Phil · #9 12-30-2008, 10:51 AM

You are gonna need a -10AN supply to the pump, -8AN to the regulator and rail then -6AN return.....I would be looking at Aeromotive or Magnafuel for the pump, regulator and filter set-up. You'll want to get a boost referenced regulator for later on. You can use the boost referneced regulator in a N/A application you just leave it open to the atmosphere.

MrN2OBelvedere · #10 12-30-2008, 11:34 AM

-10 would be 5/8" which is bigger than my pretty damn big fuel pump inlet (comes with -8 fittings). The fuel pump is a mallory 110 EFI pump. Any rationale why I should use -10 to the pump?

After a bit of thinking, I'm just going to go with the -8 (1/2") system for the return and the inlet. I realize that a smaller return is typically employed but I also think its safe to assume that the return should be able to flow nearly as much as the supply side. When you are just idling the fuel going out the return will be much more than that going out of the injectors.

I'm going to go with a stock tank, modified with a competition engineering sump. It will be expensive and a pain, but I don't intend on doing this twice.

MrN2OBelvedere · #11 12-30-2008, 11:43 AM

Not sure if everyone knows about this, but the intake and fuel rails from Edelbrock's kit can be purchased separately.

The part number for the intake is 28155. It is a pretty nice piece for certain. I am still going with my tunnel ram intake, but I figured I would throw this out there for those who might be interested in this kind of thing for themselves.

I listed the fuel rails (which I will be using) in a previous post within this thread.

Phil · #12 12-30-2008, 11:46 AM

I run a -8 supply and return which is what Mallory recommended for my application. As for the -10 from the tank to the pump......from my reading all the bigger hp pumps for forced induction use a -10 tank to pump line then -8 from there.....those pumps are cooled and lubed by fuel and they need a steady diet. With forced induction you are using a lot of fuel and you don't want the pump to cavitate.....another reson why you should run a sump. Electric pumps are better at pushing fuel than sucking it. The sump helps the fuel to gravity feed to the pump.

MrN2OBelvedere · #13 12-30-2008, 11:55 AM

With low pressure side cavitation in mind, would it be beneficial to just run the return back to the pump inlet? That was an idea I had this morning.

Phil · #14 12-30-2008, 12:10 PM

No cause you can create a foaming effect and even cause more problems. I know on my car the return is on the top right corner of the cell.....my truck returns to the filler neck like that link you posted.

RacerHog · #15 12-30-2008, 01:28 PM

Return goes back to the tank for cooling......
As for the # 10 for the inlet I'm ok ether way...
I don't think your going to run that large of an Injector and open the pulse withe that wide for that long????

Just Fuel for thought...

Phil · #16 12-30-2008, 01:31 PM

I know what you are saying RH.....but with a turbo and pushing 600-700hp I would over build the fuel system...better to have to much and have it return to the tank than not enough....plus the -10 line would only be a couple foot at the most.....it's only to the inlet of the pump. Of couse with that much HP on tap and throw a turbo in the mix I think th eblock staying in one piece is gonna be more of an issue vs the fuel line size.

MrN2OBelvedere · #17 12-30-2008, 10:13 PM

I think a lot of guys on the turbo forum might beg to differ with what you are saying about power limitations of the block. One of the oft-overlooked things about boosted engines vs. na engines is the rpm required to attain a certain power level. If I can stay under 6000 rpm and make in excess of 15psi boost then I can make a ton of torque and still stay within the limitations placed on the reciprocating assembly and block. My goal is 600 hp turbocharged, which I think is reasonable.

Since I've decided to go ahead and 'sump the tank I'm not going to toy around with weirdo ideas about alternative return locations. It does however work on paper in a static sense, but once the fluid starts moving you are right, weird things start happening, like cavitation around sharp corners and stuff.

The physical reason why you would want to run a larger line to the inlet would be to reduce the tendency to cavitate within the pump. Cavitation occurs when there is a substantial reduction in pressure at a certain point in the system. When the pressure gets low enough for a given temperature, the fluid in question will start to change state from a liquid to a gas (this is boiling). A larger inlet line reduces the amount of work that the pump has to do to move the fluid through the inlet side of the pump, basically reducing pressure drop. This is also the reason why it is better to place the pump close to the tank.

With this in mind, I think I will bite the bullet and go ahead and set the system up with a -10 an inlet to the pump, -8 from the pump to the injectors, and also -8 for the return system.

MrN2OBelvedere · #18 12-30-2008, 10:26 PM

A quick thought: the mallory pressure reg I am looking at suggests placing the regulator as close to the pump as is reasonable. The bypass comes off of the bottom of the pressure regulator. I can think of no reason why I should place the regulator after the injectors and run the return system the entire length of the car. I am thinking of placing the regulator right after the secondary filter and the return line plumbing straight back to the tank from there. Any thoughts on this?

MrN2OBelvedere · #19 12-30-2008, 10:41 PM

Quick filter question: Do I need to run a 10 micron post filter after the pump or will a 40 micron filter suffice? Will a 40 micron particle clog an injector?

'74DartSwinger · #20 12-30-2008, 10:41 PM

I like that idea. regulator after the filter back to the tank.

catfish · #21 12-31-2008, 10:01 AM

Aeromotive told me 10 micron for fuel injection, 40 micron for carbs. I have their SS system for a carb.

catfish

MrN2OBelvedere · #22 12-31-2008, 11:20 AM

anyone know a good place to buy an fittings on the cheap? I always buy from summit but if you know of a cheaper place I would like to know...thanks!

Phil · #23 01-01-2009, 09:28 AM

Summit and Jeg's will be the cheapest since they have house branded fittings now....I have a bunch of the Summit brand fittings on my car along with the more expensive Areoquip and to be honest I don't see a difference other than a lighter wallet.

MrN2OBelvedere · #24 01-30-2009, 02:47 PM

Hey guys,

So I have been working with my machine shop and also I received some parts today from Summit. The pieces I got are some of Edelbrock's fuel rails for the LA small block, and boy am I happy about these! They fit standard style Bosch injectors, are tapped both ends (3/8" npt), and happen to look pretty sweet. They're $100 and change, which is less than having them custom made would be. If you have them custom made, you have to purchase the extrusion here: ( http://www.rossmachineracing.com/dash8.html ). It is $11/ft, and you have a minimum 2' purchase. I figure you would probably want to get 3' just to be safe, so to have them custom built you would have to spend $30 on the extrustions and then easily $100 to have a machine shop make the appropriate cuts. So $100 is a good buy for some pre made rails!

I posted a few pics of the rails:

Here's an overall view:

Here's a shot of the fuel injector bores:

Here's a shot of the npt taps:

Here's the "bling" shot:

These are clearly nicely made pieces. I'm very happy with them.

I also wanted to show you the fit of the base plate for the plenum...I'll need to do some die grinding on the casting to match everything up:

I'll post some pics up of the finalized design for the top soon...

MrN2OBelvedere · #25 02-07-2009, 05:17 AM

Hey guys just to give a quick update, I have finalized the design of the tunnel ram top for EFI, with the exception of the throttle body mounting provision. I would like to place a 90 deg elbow in between the throttle body and the plenum to try to calm down transient turbulence caused by opening throttle butterflies. It is actually quite severe, and I would like to give the air flow a chance to straighten out before it has to make the turn down on the front half of the motor.

All the drawings for the parts are currently at the machine shop. They will be making the sheet metal portion and also boring holes in the runners to install the injector bungs into. Everything is made from 6061 aluminum except for the sheet metal part, which is made from 3000 series aluminum. 6061 doesn't like to be bent, but 3000 series stuff is fine with it. They are weld compatible, something you have to look out for on aluminum parts. Some of the stuff can't be welded at all. The tubes are from mcmaster, and the screws will drop down inside of these tubes.

The calculated weight for the top is 2.9 lbs (much lighter than the original top), and the volume is about 480 cubic inches. This will be plenty of volume for the 360 or the 408 should I decide to stroke it.

Well let me know what you guys think and I'll post some pics of the finished parts.