hi there, im just wandering why people stil need to use 8 injectors when 1000cc are available etc can you get morw accuracy or something? ive got 550 high imp at the mo and am just wandering which route is better for more power and out of curiosity!!

 

second injector rail mostly is installed farther then primary

fuel have longer way to the cylinder and it can vapourise better, and it have more time to

take away some heat from air and improve charge density

using only one rail far inlet valves isnt good for low revs

 

It is nothing to do with the amount of injector rails this merely supplies the injectors.
It is the siting of the injectors, with 8 you can optimise for low speed torque, where they will fire at the back of the valve to futher away STRAIGHT down throat where they will have longer to mix being combustion, as said it also helps with latent heat absorbtion.
Advances since 8 injecotr days in the area of ECU makes this(almost) redundant now, as you can get ace fuelling across the board with large injectors as better maps are available.
tabetha

 

4 large injectors usually make for poor emissions @ idle

 

8 injectors are for tuners who are "stuck" in there ways or for those who
want the "bling" effect....


.... All IMO of course

 

Sorry mate but not if mapped correctly by someone who knows what they are doing.

 

and thats coming from someone named mapping dude

 

like me who has got some cars to pass cat test (without a cat)
and some carbed cars for that matter.
I Speak from experience.
(not cyber experience)
The bigger the injector generally the worst the emissions will be .
I try to help people on this forum and give another opinion.

 

There are two elements that affect the ability of an ecu to control large injectors at small pulsewidths;

i) The resolution in the software to command the small pulsewidths required at idle. i.e. not all ecu's have the ability to do this.

ii) The ability of the hardware to drive the injectors open fast enough and for them to close quickly enough to produce repeatable small pulsewidths. Again, this depends on the ecu and injectors.

So, it it is not as simple as saying whether 8 smaller or 4 larger injectors is better and you need to know about the system controlling them.

 

Perfect answer. Saved me replying.

 

Hence my original reply

 

put big injectors on std weber IAW and emissions are terrible .

 

A little meaningless unless you Define "BIG" mate.

 

I'd like to say "I was gonna say that" but I wasn't Makes sense to me though

 

You obviously dont know what you are talking about

 

Don't think big is going to get defined!!!

 

daz i think he means american style injectors, you know BIG, like the people!

 

But big can mean different sizes! All big but all different!!

 

Shall we agree that in this instance, 'bigger' means 'higher flow'?

 

They were greys .
On a chipped Iaw ecu. saw a few ,all had crap emissions.
but wow,this forum has some serious flamers in here dont it?.you really welcome new people dont you.
takes all sorts i guess.

 

The greys had nothing to do with the poor emissions i assure you. It was just bad mapping.

 

These days, greys are considered as "not big".

Unless used on an RST.

 

they had off the shelf chips in by so called cossie specialists.

 

Thats why!

My Dad's car runs at lambda 1 on 890cc injectors and returns 30 mpg on Marelli.

 

I think your Dad should change a new one.
The car is too old.

 

Having recently had my engine re-built, I went for the WRC 8 injector route purly for emmisions. There are more and more Police carring emmision testers in their cars and because of the "Greenies" pressure fines are now quite high.
As you can argue that the car can only be tested to the same as MOT standard (on tickover) 8 injectors gives you the best chance of passing with a tuned engine.
Maybe I wasted my cash, but at least I feel safe if pulled over.

 

hmm.
basically someone else who didnt know what they were talkin about told you to use 8 injectors?.

 

Your emissions have as much chance of being illegal with an 8 injector set up as they do on a 4 injector set up. It's all down to the mapper and condition of the car...

 

Has any one done a back to back using the same car?