any suggestions whether I go injection or efi? im totally stuck. how much do they go for?

What's the difference?

do you mean MFi or the EFi, and what engine is this?

i've heard injection is cheaper and easier to maintain but you do have to cut a massive whole in your body.

carbs sound better, slightly more power but cost a whole load more and there harder to maintain?

is that correct?

(i got a 2litre silver top zetec)

sorry if Im wrong, I assumed EFI referred to carbs...?

[Edited on 4/4/07 by jimbona2]

Jim

EFI - Electronic Fuel Injection.

Its all horses for courses.... Some like carbs, others swear by injection. Most post 1995 engines won't pass emissions with carbs and a catalyst, so its a no choice option.

I prefer carbs and electronic ignition, which gives me some flexibility over a distributor. But then again, I've got a Pinto...

Cheers

Pete

i'll go the injection root as it seems so much easier and cheaper...

quote:

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Originally posted by jimbona2



sorry if Im wrong, I assumed EFI referred to carbs...?

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on that thought why are carbs slightly quicker when injection is actually forcing the fuel in and not having to suck?

quote:

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Originally posted by jimbona2
on that thought why are carbs slightly quicker when injection is actually forcing the fuel in and not having to suck?

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carbs produce more bhp

Although twin side- or downdraught carbs might (note the might) make slightly more power than EFI at one point in the rev range they will never in my opinion give as much driveability and power throughout the rev range as properly tuned injection with throttle bodies.

Also once tuned EFI is a low (very) maintnance item whilst carbs are not.

Its all about comparing like with like - in this case the airflow of the actual induction system.

Most production car fuel injection systems flow air like a single SU carb on a 1 litre mini (think of an asthmatic donkey). This is why they produce less power than Twin webers or bike carbs (think of a racehorse with an apprentice jockey).

Injection Throttle Bodies have the same (ish) flow as weber carbs. Here the advanced electronics produce more power than Webers (think of a racehorse with a champion jockey).

I.e. a Zetec 1.8 is usually expected to produce 115hp on factory injection, 145hp on Webers and 155hp on Throttle bodies.

Hope this helps.

P.S. factory ecus run very conservatively too - all in the name of emissions

it probs depends on what carbs and what injection set up you compare.

Twin 45's vs single point injection, id say carbs may be better.
However 38DGAS etc vs jenvey etc setup then id say throttle bodies will be better.

Im running Pinto same as PeteW, bike carbs and MJLJ is about as much as you need. Throttle bodies may be better but maybe not cost effective.
If i was to fit Zetec id probs go the full hog and fit throttle bodies.

Ref cost - all depends how you are going to do it. In my mind carbs wil be cheaper all in. However ive seen some extremely tidy throttle body installs based on bike injection and megasquirt which was very cost effective (maybe £500 all in). Depends how canny you are with your purchases and if you can wait to snap up some bargains.

how do I know what webbers or carbs go with my engine?

I believe for a 2.0 Zetec you would need twin45's as the performance option. You could also opt for bike carbs - eg R1, blackbird etc. Im going to use ZZR1100's on pinto. Coozer is also fitting same to his Zetec.

Just a small point based on your question on what webers or carbs to use. Weber is just a manufacturer name for carbs. The other well used type for cars are Dellortos. Keihin is a manufacturer of bike carbs.

If you go for carbs you can also use megajolt (MJLJ) to control the sparks via the std Zetec EDIS and coil pack. The Zetec will already have a VR sensor attached engine that takes a signal from the flywheel (the 36-1 tooth wheel is cast into the body of the flywheel). For 3D mapping its easier to select carbs that have a TPS already fitted or just attach an aftermarket one to the carb throttle spindle. Approx £100 should get you sorted for ignition.

If you go the DIY injection route you can use megasquirt to control the injectors and also the sparks.

To be honest if you are starting from scratch you might be better off going injection route as costs wont be much more. You will still need a manifold, bike throttle bodies are same cost as for carbs (ish). The only extra is theat megasquirt ECU is a little more expensive that megajolt but several have reported far better economy for the same power and possible a smoother operating and more responsiveengine as a result. It wont be long before you recoup the extra cost in fuel savings. The megasquirt will probs only be another £100 or so. At £4.20 a gallon, based on a conservative extra 5mpg (25 to 30) you will get your money back after 3000miles.

All based on my reasearch rather than first hand experience. tangoman has just got his Zetec running on bike throttle bodies and megasquirt - it could be worth asking him what his experience is. He did report on Monday to be getting 35mpg ish on a run, a figure i can only dream of with carbs (im getting 25 ish with 38DGAS, hoping to get higher 20's with bike carbs).

[Edited on 4/4/07 by DarrenW]

How can you say carbs are better than injection?

A good carb system will be better than a bad injection system... but a good EFi system that is properly set up will always produce more power and be more reliable than a good carb based system. At the end of the EFi is infinitely adjustable, carbs have about about four things you can adjust.....

thanks for the great info.. Injection it is then as Ive never touched a car before now.
Does i t matter if the inlet manifold is from a turbo rs or not?

Jimbona

Go for injection. I had bike carbs on my pinto but opted for independant throttle body injection for the zetec.
The bike carbs were never right at all rev ranges so were very rich in places, but still better than standard. The variable venturi makes them better than webers et al for low throttle running.
EFI is soooo much better. With the Megasquirt you can map a 12*12 fuel table to ensure you have the mixture right at all times. A wideband sensor finishes the package as you can them monitor and run in closed loop to ensure you have rich mixture where you want power and lean mixtures for cruise.
As DarrenW says' am getting 35+ to the gallon and I am still a bit rich.
The costs will be slightly higher but the trade off is worth it. You will need to buy an ECU anyway to run the Zetec as it has no dizzy so by the time you have sourced ECU, Carbs etc you may as well have done it properly.

just had a word with tiger and they're saying the performance kit is easy, just take it out of the box and it fits in? its £1300 (+vat) new.. They dont seem to offer any advise/ help for injection with 2litres..

not sure if its sales jargon or not but they said zetecs are fine but they normally only support up to 1800 because the 2 litre (as I have) causes a load of problems..

Confused now, injection seems to be the general opinion here but tiger think otherwise and they reckon its as easy as 1-2-3 with the performance kit...?

[Edited on 5/4/07 by jimbona2]

that sounds strange as i thought the 1.8 and 2 litre were broadly similar? certainly from an ignition and fuel point of view for EFI? obviously you would need different maps but the hardware would be the same

i'll give them another call and let you know about 1.8 and 2 litre difference..

am I right in thinking that injection and carbs are the same sort of price and that throttle bodies although give the best performance are more expensive and far more hassle?

Throttle bodies are part of a fuel injection system.

You can either go for a single throttle body at the end of a plenum chamber or individual throttle dodies - 1 for each cylinder.

Most people on here will use the 4 throttle body route for a 4 cylinder car.

Think of it this way. A standard single carb that feeds 4 cylinders via the inlet manifold is similar to the single throttle body and plenum idea. It will work but not what you would class as a performance package.
Twin 45's etc are basically a carb for each cylinder and would compare to individual throttle body injection.

If you then compare throttle bodies to twin 45's etc then injection would be the winner. Not necessarily on huge power gains but certainly on probs a bit more power with better economy and drivability.


Ref costs - you can go all out for a full Jenvey and OMEX / Emarald ECU set up. Probs fit and play but circa £2000.
Bike throttle bodies and megasquirt can be done for £500 - 600 ish. Will need some research. Maybe specialist set up if you are confident. Some debugging to do but can give similar performance and drivability for a lot less money. This conversion is suited to the techy's who enjoy a challenge and fiddling.

For £1300 as an off the shelf conversion i would geuss that is a single body / plenum set up. It will work but you may not get the most performance out of it.

Following that you are into the carbs and megajolt territory which has been discussed already.

A lot depends on your wealth, patience, skills etc. After seeing Tangomans set up its defo worth looking into bike injection and megasquirt, quite a lot of people have done it and should be able to help you out.

The £1300 plus VAT from Tiger is for the Weber 45s plus Webcon Alpha setup IIRC

Cheers

Pete

think i've got it now. had a long chat with tiger and basically if you have a 2l zetec you cant go for the injection root because it basically wont fit, forget the emissions and all that but apparently it just wont fit in the chassis or within the body for that matter.

I've been informed the only way to have injection is with the 1.8 or lower engines, 2l and beyond just wont have it.

The 1.8 injection unit is around £800 not to mention getting a different engine and although it will still shift I dont wana go backwards in engine size... So for a bit more cash, namely £1300 I can use my 2litre

And all this means I dont have to cut a ruddy great big whole in the bonet.

Hope thats all correct, just relaying what I've been told to help my cat undestand it all.

dam, need a handbrake and they're not open on band holidays