[HayBurner408G]

Hi all,

I'm in the process of building up a t1 beetle engine, and am exploring EFI. The longblock is built as a 1915cc. I am looking at an ITB solution and doing as a DIY/scrapyard jobby sourcing bits as and when I can. Ive read the getting started bits but have a few questions:

Can I use the points trigger from the original dizzy? Ie rather than fit a crank trigger wheel.

Sensors wise what is the minimum possible - surely MAP, TPS, and a lambda Is all id need? It being air-cooled and having next to no electronics I'd like to keep as simple as possible.

I have seen the info about injector types, but any common vehicles in the UK that run high z injectors to keep an eye peeled for?

I think manifolds wise I can sort something out by using older castings and modifying for port injection - throttle bodies I imagine will be easy to sort from a motorbike (thinking CBR or gsxr)

How reliable is the software? Any beasties to be aware of?

I am studying engineering at uni and have a background in primarily mechanical however have experience with Arduino and automotive electronics.

Many thanks

Toby

[LAV1000]

You need at least also 2 temp sensors one for IAT (Intake Air Temperature) and one for CHT (Cylinder Head Temperature).
Drop the points and make a nice crank wheel, would be no issue for someone whit mechanical skills.
Search the forum there are a few more working on air cooled (beetle) engines.

[PSIG]

Can I use the points trigger from the original dizzy? Ie rather than fit a crank trigger wheel.

Sure, but realize that every choice you make holds compromises. As @LAV1000 stated; note some other successful projects here have used everything from stock distributors, to multi-tooth wheels in distributors, to crank wheels, with varying levels of resolution and prediction. What you choose should be based on what you need it to do. If you want or need good precision and timing control, you should apply a good trigger system.

Sensors wise what is the minimum possible - surely MAP, TPS, and a lambda Is all id need? It being air-cooled and having next to no electronics I'd like to keep as simple as possible.

The minimum is whatever level of additional error and crippling you are willing to tolerate. Unlike some mechanical systems that thrive on simplicity, the difficulty and frustration are inverse in EFI. The less it has to work with, the less it can do well. I can tie your fingers together, then your hands and feet, then tape your eyes … soon you will find it very difficult to get tasks done well. Use care in incrementally crippling your system.

I have seen the info about injector types, but any common vehicles in the UK that run high z injectors to keep an eye peeled for?

For now and until you find by testing what your setup really likes, it would be most important to select the flow for your actual engine power expected. In modified T1 types this figure is commonly and grossly over-estimated. Comparing similar setups, 100-150cc/min (10-14 lb/hr) would be expected. Injectors of that range are very common, and searching EFI 4-cylinder engines near your anticipated power range is one way to initially find them.

Of course select injectors that physically fit and function in your setup first. Follow that by reasonably accurate flow sizing at your expected pressures, and finally high or low-Z. Speeduino can use either type, with inline resistors to use low-Z quite successfully. Rule #43: If you compromise or let your ego step-in, you decide to limit your options or ease of reaching your goals.

I think manifolds wise I can sort something out by using older castings and modifying for port injection - throttle bodies I imagine will be easy to sort from a motorbike (thinking CBR or gsxr)

Again, your choices all have compromises. Generally, including plenum(s) will provide better control and a wider torque band, while ITBs can sacrifice those for peaks of power if the system is well-tuned harmonically (including valve timing and exhaust).

If the choices are for random reasons, that's fine, just be aware of what you are giving-up — or the extra testing and work required to make it perform as well or better for specific purposes. When you do unusual stuff you get unusual results, and if done randomly, they are also random whether they are in your favor.

How reliable is the software? Any beasties to be aware of?

Generally reliable, but it is an experimental system, where certain applications may find specific weaknesses. This is all part fo the development process. Most of the overall system reliability is based on your quality of design, components, and construction or assembly of every part and connection.

I am studying engineering at uni and have a background in primarily mechanical however have experience with Arduino and automotive electronics.

Excellent! Apply the skills you have acquired to this and expand your horizons!

David

[HayBurner408G]

thanks for the great replies, given me some food for thought. I can already tell this is going to require a fair bit of swotting and a bit of trial and error.

Is there any further reading you would recommend? anything you would have done or researched in hindsight?

thanks again,

Toby

[dazq]

In the UK , Peugeot 1.6-1.8 , ford 1.6-1.8 zetec and rover k series 1.8 have injectors ranging over the 130-170cc flow in high z coils.
Mondeo 2.0 and fiesta 1.6st have 180+ injectors if you want a bit more
I lookup the injector part number on this web site for the data needed.
http://users.erols.com/srweiss/tableifc.htm

[Jhgmx111]

In the UK , Peugeot 1.6-1.8 , ford 1.6-1.8 zetec and rover k series 1.8 have injectors ranging over the 130-170cc flow in high z coils.
Mondeo 2.0 and fiesta 1.6st have 180+ injectors if you want a bit more
I lookup the injector part number on this web site for the data needed.
http://users.erols.com/srweiss/tableifc.htm

Are you completely sure? I own a rover 25 1.4 (serie k), and as far as I know, my injectors are 248cc.
It is strange to have bigger injectors than the 1.8 you mentioned.

[dazq]

Yes the blues I took from my mgf engine are only 190cc , the beige vvc are only 210!
Fuel pressure and number of injections per cycle have a big effect on required size

[PSIG]

… as does fuel type. If the engine is flex-fuel capable (E85) or in a transition year, then the injectors will be much larger. Choose your fuel type now so you can plan well, noting I mentioned straight gasoline/petrol in my injector size estimation. My estimations are partly based on the engine's thermal capabilities, where you might make it down a short drag strip while exceeding the engine's ability to shed heat, but not longer applications without other modifications. Be sure you use very good fuel pressure control and good resolution if you oversize the injectors, as that is yet another compromise.

David

[HayBurner408G]

Hi all - cheers for chipping in, a lot of this is still new ground for me.

Ethanol is something I would avoid as it likes to eat fuel lines - seeing as the car is only used whilst im back from uni I tend to stick high octane fuel in with a low or no ethanol content. Thanks for the injector info site and common uk cars, gives me an idea what to keep my eyes peeled for.

Ive done a little more reading (and got a few secondhand books on EFI on the way) and I think for simplicity's sake I will first use an electronic points conversion in a no advance dizzy as the trigger. I will in the meantime also explore trigger wheels but like the dizzy idea as it looks a little more period.

I have seen some throttle bodies that actually have the injector bosses within them, alongside a tps and a couple other sensors (more research needed!) ie CBR600 and R1 throttle bodies have injectors below the butterfly (some have 2) and you can split them into 2 banks - perfect for a bug. This also means I can make or modify some manifolds without hacking them up to fit injectors - does this sound like a good idea or am I barking up the wrong tree?


I have balanced and weighed the engine to an inch of its life and has a forged/counterweighted crank and a nice cam too, which I think would suit throttle bodies nicely. I understand I would also need a swirl pot and electronic fuel pump ( - rather than a tank return line could I vent to the swirl pot?)

I will try get a couple drawings of what I am visualising in the mean time.

Cheers!

Toby (Semi buggered 68 beetle)

[PSIG]

Concept: viewtopic.php?f=19&t=1682&#p24628
Higher resolution while retaining the stock distributor. He only wanted function over appearance, and I've seen more stealth employed. Single-wheel missing-tooth at cam speed permits all modes through sequential. Just throwing ideas. That said, I'm not following your period-appearance theme, with ITB MC throttle bodies.

I understand I would also need a swirl pot and electronic fuel pump ( - rather than a tank return line could I vent to the swirl pot?)

This and this (and several other threads) helps to outline the need to separate air from the fuel system when using a non-baffled tank or air-ingesting pickups. Simple is with a return, which can be easily placed (including into your fill tube) with push-in fittings. Other methods can certainly work, but tend to rapidly increase in cost or complication. The pump may be contained in the surge tank if desired, along with a regulator, and the main-tank feed may be by gravity if oversized and low, or by the stock pump as other options. Lots of options for a system that feeds with no air to the last drop.

David