Fitting Fuel Injection to a Carb Car

[WestonE]

I was recently asked about how to fit Modern FI and mapped 3D (load sensing) Ignition to a Carb car without it being too obvious. This is not a simple task and decisions have to be made on how far the associated engine is tuned.

Basic facts
if a single throttle body is used both chokes opening together is better. Think Retrojet DGAS from Webcon fitted to a modified and gasflowed OE Carb manifold
1 choke per cylinder gives better power and economy for given engine speed
Side Draft gives more power than down draft BUT needs a modified radiator set up and great care to get cold air to the intakes. Think Heritage DCOE look alike throttle bodies from Jenvey
The straighter the airflow the better BUT
Hot air loses power and risks engine wrecking uncontrolled combustion called detonation
Long trumpets and long inlet length aids mid range torque on the TC. I know I have built enough of these to know. Check out the Group 4 pictures
Longer Duration cams or inlet only cam need higher compression pistons i.e. 10:1 minimum with 11:1 better and a 4 into 2 into 1 exhaust with matched lengths
Downdraft carb pattern Throttle bodies. Think Jenvey DCNF style Throttle bodies give more scope to keep the existing radiator. BUT they MUST have an insulated air box fed with cold air to give the best result. This is an opportunity to hide them for that stealth look.
You need a modern ECU modern sensors and trigger wheels so forget bits of old Beta IE FI
A 36 - 1 tooth trigger wheel is essential (engine speed) as is load sensing Throttle Position Sensor or Manifold Air Pressure Sensor
Air Temperature and Water Temperature sensors are essential
A wide Band Lambda sensor can tune the system for you in real time BUT rolling road mapping is still essential
Coil per plug ignition only works with Sequential injection
Sequential Injection needs a cam position sensor ( adapted from an Integrale distributor on a Beta IE cam distributor drive)
Batch Injection 1&4 2&3 and Wasted Spark Coil pack will do all most people need
FI needs high pressure filtered fuel supply and does NOT tolerate fuel surge. Twin 8mm fuel lines shielded from exhaust heat feed & return are essential. A swirlpot and high pressure pump like the webcon integrated pump and swirl pot lets you use your carb tank
No body has an existing ECU map for your car that is worth using and trying to drive to a rolling road on a start up map is a very stupid idea. Get it transported or load a trailer.
A good rolling road can map you car in 2 hours with a morning check on cold starting if you have a good ECU.   
ECU's have to be wired into your car and will need a relay and fuse box creating as part of this. It is easier than you think with a written or typed connection plan.

Why Bother?
Pass every emission test HMG will present.
Instant starting & perfect running in cold weather or hot weather
More power AND better fuel economy
Nicer to drive
More reliable - Provided you installed it properly

Enjoy!!

Eric     
300BHP Fuel Injected and Supercharged Montecarlo with a Link G4+ Fury ECU and Drive by Wire

[squiglyzigly]

Eric
Thank you for taking time to make this valuable post.  I’m sure there are several of us wanting to make such upgrades to our cars sooner or later, myself included, and you’re patience to keep helping with endless questions on this topic is appreciated.

All the best for the new year
Ian

[WestonE]

Hi Ian

Thank you. It is good to know someone noticed. Over time I will try to add some pictures of things like the trigger wheel and sensor install. The only bits of IE I could have mentioned using are the fuel tank. The manifold and throttle body could be used but you would be fitting a new Throttle Position sensor and a new fuel rail to suit modern injectors.

Happy Christmas

Eric

[mangocrazy]

Nothing you post goes unnoticed by me, Eric... 

At present I'm intending to continue with my plans to use twin DCOE 45 Webers with my newly rebuilt engine, but am certainly interested to see what would be needed to convert to FI in future. I guess it all deoends how well the car runs on the DCOEs; that will determine whether I decide to convert to FI. Is there anything I can do now to prepare for a future conversion to FI that I can install/bolt on that won't affect carb operation but will make future conversion to FI simpler and easier?

[WestonE]

Hi Graham

Aside from collecting the bits to install the sensors and fuel pump. Having twin 8mm fuel hard lines installed is essential. For twin carbs the second line can be capped off.

Enjoy

Eric
Practical Performance Car September 2020 shows how to fit a Land Rover High Pressure Pump and swirl pot to a classic tank. 

[WestonE]

Some personal views on ECU’s

ECU’s are computers that interface to computers, so they can go out of date like computers. The processors can be too slow, they can have too little memory and out of date interfaces. They may not work with desirable optional extras like shift lights and sensor displays driven by CAN technology. The casing can be far too big making installation a pain.

The software that they need can be dated short of features, un- finished and lacking both support and an upgrade path. Some charge for adding software features later so beware. Some have no Data Logging which is an important tool for the tuner to understand problem areas.

Few modern ECUs have an on board high side Tacho drive i.e. 12V. They will send out a 5V low side signal. Fortunately there are multiple cheap solutions to make your existing Tacho work. This should not be a reason to not choose an ECU. In fact be suspicious about how dated the ECU is if this is a major feature.

I have owned so far Lumenition (which became OMEX), Emerald and Link ECUs
Buy the ECU last after you have the engine Throttle Bodies and Sensors installed and buy the latest NOT a second hand bargain. This is no time to for buy the equivalent of a Windows XP PC.
Personal views:

Lumenition which became OMEX – solid basic ECUs with dated Windows 95 type software and limited interfaces.

Syvecs – Brilliant high speed Time Attack series ECU. Fully featured machine code level software and modern interfaces. Very expensive and beyond your wildest needs

MegaSquirt – Open Source DIY ECU’s. Many Rolling Road Tuners will not touch them. You can even build your own from components. Dated Designs and Dated Software with wing and a pray support set up.

Emerald – Heavily promoted and widely used. But out of date hardware with software not finished in some areas. Mapping is hit and miss with some shocking jobs done and some tuners refusing to use them anymore. I no longer recommend them.

Pectel – Basic ECUs not well supported or developed. History with Cosworth tuning. Better than some but avoid.

Motec – Horribly expensive and they take EVERY opportunity to charge you more trading on a wide Motorsport history. Well supported, but for the rich racing team who want comfort and have not yet heard of Syvecs or Link

DTA – A solid economy choice, but thin on features so you need to take care that the box does what you need. Support is a basic old Forum model.

Haltech – A really strong range of current ECUs with a strong dealer and tuning network. A big business in the US and good support. Consider their offering as an obvious replacement for Emerald  and a real short list contender.

Weber Alpha – More of a hobby project add on than a serious ECU. Out of date missing features Etc. Avoid

Link – New Zealand Based creator of deeply featured fast ECU’s used heavily in highly tuned drift cars and increasingly in the full range of tuned road cars and motorsport. I use the Link G4+ Fury and I have been delighted by both it’s capabilities and the support both in the Link Software on the active forum and by email. Great value compared to others so look closely at the Atom ECU for your needs. I am using the Fury to control a drive by wire throttle enable traction control, display all of the sensor information, enable a shift light array and provide full digital wide band tuning whilst I drive.

VEMS – Dated and with confusing support. But better functionality than many big name ECU brands. I wish you good luck working out how to install it and tune it. Their dated website tells you what you are in for.   
 
These are my personal views intended to help you. Do your research and make wise choices including who will be available to map your ECU. Beware the shiny new Rolling Road established last week by 2x 30 year olds, someone who has never mapped your particular ECU, or someone pining for the old days.  Let them practice destroying engines on someone else’s car.

Do NOT let the junior or apprentice anywhere near mapping your car whatever the reason given. I experienced this at Emerald. Better to pack up and leave.

Eric

 
 
       

[peteracs]

Hi Eric

Many thanks for this as you know I am getting you ducks in line to start buying parts for an engine build next winter.

Peter

[mangocrazy]

Hi Graham

Aside from collecting the bits to install the sensors and fuel pump. Having twin 8mm fuel hard lines installed is essential. For twin carbs the second line can be capped off.

Enjoy

Eric
Practical Performance Car September 2020 shows how to fit a Land Rover High Pressure Pump and swirl pot to a classic tank. 

Thanks Eric. What material would you use for the 8mm hard lines? Will Cupro-Nickel (as for brake lines) suffice, or is there a better material to use? I can appreciate that stainless would be good from a corrosion-resistance POV, but it's tough stuff to work with.

And I wasn't surprised to see Link as your preferred ECU option. Those Project Binky chaps are agents for Link and they don't use or recommend anything substandard.

[WestonE]

Hi Graham

I ended up using Copper Nickel in imperial size with Compression fittings from Torques, but Aluminum would have been easier if I had it with the right tube nuts and sleeves. NB Tube nuts and sleeves need a 37 degree flare and the sleeve re-enforces the flare. Watch some you tube videos for how. Just do not expect imperial fitting to go on 8mm metric pipe!

Competition Supplies or Merlin Motorsport stock these things.

Eric

[squiglyzigly]

Hi Ian

Thank you. It is good to know someone noticed. Over time I will try to add some pictures of things like the trigger wheel and sensor install. The only bits of IE I could have mentioned using are the fuel tank. The manifold and throttle body could be used but you would be fitting a new Throttle Position sensor and a new fuel rail to suit modern injectors.

Happy Christmas

Eric

Evening Eric
I’m looking forward to your next episode of ‘how to fuel inject a Beta’.
My latest digging through boxes in the loft has unearthed a few goodies that I hope to use for mappable ignition to start with and then evolve to injection on the VX.
I think I have a distributor to use for cam position. It is a twin lobe (not 4 lobe) Hall effect with fixed shaft (no advance). Is this the type you used for cam position? Presumably slimmed down to single lobe?

Cheers
Ian

[WestonE]

Hi Ian

If that is the distributor from the Integrale with a Hall sensor inside that is exactly what I use to enable sequential injection with a cap from a Branston pickle jar on one and Lidl Strawberry Jam on the other. Sadly now over painted after I got tired of the joke. You have to trim off one of the 2 lobes to get the signal correct. I will have to dig out the information as it was some years ago I did mine.

Eric
PS Tanc Barret supplied a new hall sensor and lead for mine.

[peteracs]

Hi

Came across these folk and wondered if anyone has any experience?

https://spitronics.com/

Peter

[WestonE]

Hi Peter

I have literally never heard of them and wonder how many knowledgeable people they have in the UK? I have not reviewed the solution as I do not have the time at this point.

Eric

[peteracs]

Hi

Their (only?) agent in the UK is

http://crsperformance.co.uk

Whose parent also appear to be South African where the units are designed and made.

I have asked for UK references of users and tuners and will see what comes back.

Peter