Switch from triple DCOE45 Webers to fuel injection

[barberoz]

G'day.  I can't get rid of that fuel smell that goes with webers when parked. Has filters not trumpets. Has anyone done a swap to fuel injection? If so does it eliminate the fuel smell?  Look forward to your experiences. Thanks.

[droopsnoot]

I'm watching this as it's something I've thought about doing on my car, but for smoothness rather than performance or getting rid of a smell. Mine are Dellortos, though, but basically the same. If you've plenty of money and want it to have a more "classic" look someone does a throttle body that looks like a Weber, and contains the injectors inside the body. I did wonder if I could just get a pair of old 40s that I have here, use them as the throttle body and then just modify the inlet manifold to have the injectors, perhaps underneath the inlet tracts so they're not obvious.

[pptom]

I replaced the pair of 40's on my Elan +2 with Fuel Injection. GSXR600 throttle bodies and injectors essentially with Omex management.
Night and day difference. It only made 10bhp more at peak, but the driveability was on another level, it used 1/2 the fuel and I never smelt fuel again. I recently sold the Weber's for more than the conversion cost - minus the rolling road mapping charges.

[pptom]

[ChasR]

In short, yes it will near enough eliminate the smell. I've certainly not smelled fuel on an aftermarket ITB'd car.

You *may* lose peak power due to losing the cooling effect on fuel when going from carbs fuel injection, but several other things should improve, including

-Reliability
-Consistency in a tune and running
-More power under the curve (which may also come about from improved ignition mapping, which could also improve peak power)
-Improved starting
-Potentially better MPG

And other things.

The cost depends entirely on the way you want to go. As a rough guide

-ECU - £200 to £1.3k

This depends on if you want to build up an ECU kit yourself from scratch from Speeduino or Megasquirt, or go with something ready to go, which Megasquirt also can do.

For something more Rolling roaders are familiar with, the 'established' brands would be your port of call, but of course, cost goes up.

-Engine bay stuff

Googling for a similar kit, using Jenvey Kit from a 240Z, it looks like it's around £2.5k for linkages, ITBs, injectors, sensors etc. I took out the manifold, as you should be able to use what you have.

This could be cheaper by seeing if a contemporary manifold fitted, which would drastically bring down the cost. It may come with a power penalty to the ITBs and Webers, but you'd still have improved driveability, assuming the cam's not too spicy etc.

ITBs from bikes work well, but it's a question of whether you are fitting these yourself, or getting someone else to make something up, which can soon see the costs go alot higher.

-Ignition (£200?)

You'd need a decent coilpack, some sensors (Crank sensor etc), and some leads to fit up to the coilpack. Mounting brackets would likely need to be made up for both of them.

-Rolling road tuning (£1k?)

I did get a cost a long time ago for tuning my car up on a rolling road, as well as helping friends get theirs done locally, and it was almost half the price I put above, but that was some time ago. I've put that up as an estimate.

-Fitting

If you can fit the hardware yourself, that will be a nice saving. It's a question of competence and what your abilities are. I'd suggest wiring it yourself as well, but I've seen many folks make simple errors when wiring things up for EFI. Again, it's a cost.

I've probably forgotten a few things, but that's my take on how much I reckon it will cost. A few here will know more about the in depth costs.

Regarding the fuel smell in the interim, I notice you're not running a heatshield between the carbs and the manifold? If not, I'd fit one. If you can't, I'd either wrap the manifold or get it ceramic coated. It should then reduce the heat getting to the carbs, and reduce the smell.

PS, that looks lovely.

[pptom]

I can probably add a little on costs for my 4 cyl system
ECU and loom £700, Omex, emerald etc will supply a base map which will be good enough to drive the car, also very good support from these British companies, that was the reason I paid a bit more than going for megasquirt etc, I can do spanners and brackets, not so much circuitry / programmingI I also found out later that my local rolling rd hates megasquirt etc I think he said so much time can be taken up / wasted by just getting the ECU to communicate and work properly
Rolling road for me was about £350
Bike throttle bodies and injectors about £80, but they're not bolt on like jenveys, quite a bit of fiddling to fit, but it was a nice winter project for me. Jenveys don't look too bad at about £400 each, but I found that when you add on all the parts you need like injectors, linkage etc, a pair of jenveys added up to about £2k
Ford coil pack £40
Ford crank sensor £20
Trigger wheel and sensor bracket, think mine was about £100?
Fuel rail £40?
Trumpets / velocity stacks £40
Air filter and backplate £80?
Inlet rubbers £80. The rolling rd place said that alot of people don't properly mount bike throttle bodies to the inlet stubs, so they move around and have big steps in the airflow.

Don't forget you also need to beef up the fuel supply system, so you have a low pressure fuel pump (existing) typically 2 or 3 psi, the new stuff you will need after that are a swirl pot, then onto a high pressure fuel pump (3 bar typically), fuel filter, then feed to the throttle bodies, you then need a pressure relief valve which vents excess / unused fuel back to the fuel tank, also hard (cunifer) pipes for the 3 bar fuel. There are a couple of ways of doing this, but that's what I did.

I am very far from being an expert, just my experiences.

[slater]

Does that engine use Siamese inlet ports? If it does that will most likely give you issues with charge robbing. Not unsolvable but tricky.

[v8ian]

Always a good move, Injection from carbs, and almost certainly the smell will go, Webers drip fuel, floats lift and all sorts of weird issues, I converted a RV8 to downdraft ITBs many moons ago, brilliant move as far as I was concerned, TBH my webber setup on my c20xe will be going direct to head injection over the winter, I'm too, fed up the the smell of dripping fuel.
As for your engine, do you want to keep the looks of Webbers, as you already have the manifold,Jenvey do make a "Classic" ITB which look almost Identical to a real webber, But saying that, I think there are only 3 Jenvey bolt patterns, IDAs , DCNFs and DCOE. so you would need to order the correct style of Bodies if going for the normal ITBs. As for ECUs I have always used Emerald, but I'm guessing they are the other side of the world from you? A possibility that I might explore on my next ECU is "self learning" obviously they will need to be using engine parameters, and I'm not entirely sure how aggressive the setup will be, probably better for economy than performance, and I will guarantee the fuel consumption will be much better than the Webbers.

[kevins]

A full airbox and remote air cleaner would help with the smells, I don't get much in the way of fuel smells from my elan on dellortos with this set up.

[v8ian]

Jul 17, 2023 17:32:30 GMT pptom said:

I replaced the pair of 40's on my Elan +2 with Fuel Injection. GSXR600 throttle bodies and injectors essentially with Omex management.
Night and day difference. It only made 10bhp more at peak, but the driveability was on another level, it used 1/2 the fuel and I never smelt fuel again. I recently sold the Weber's for more than the conversion cost - minus the rolling road mapping charges.

Only made 10hp more !! for not opening the engine, thats a real result,

[pptom]

👍
This is pre and post FI, but already had the ECU running ignition only, this wasn't altered between the runs.
First graph is Weber's set up on the RR, 50 years old so maybe a bit worn out, but rebuilt. Pink line is the AFR and should be as straight as possible



And several months later, same engine with FI



You can see down the rev range they are just bucketing fuel in, smelt like driving with the choke out if the exhaust fumes caught up with you. I seem to recall that if we corrected this they would run too lean in the midrange, carbs are just too much of a compromise for me.

[barberoz]

Thanks for all the info peoples. Definitely going to inject. This mob in Aus seem to have a good handle too. Might suit some of you as well. www.efihardware.com/products/2015/Holden-202-pro-race-DCOE-tapered-bore-kit-45mm.
There are some nice conversions that some of you have done.
PPtom, Charles and V8ian ... lots of helpful info. Thanks.

[barberoz]

Thanks ChasR.