series_one_rst

almost ready to build up my s1 and was thinking of upping my injectors as the cosworth ones i've got aint gonna be good enough. thinking of putting vxr or dekas in but my ecu is set up for low impendance. its it much of a job to swap to high and is it worth it?

studabear

who built the ecu? they might know.

I've just got mine running on deka's, not driven it yet as it needs mapping and isn't taxed till next month.

I would say a plus point of getting it modded is that you can get a set of brand new deka's for £180 ish, thats including getting stitched for import tax, if marked as gift poss as cheap as £150 for 4 very modern injectors is a bargain.

Rob_DOHC

iTrader: (4)

As above, who built your ecu? by default megasquirt is only set up for high impedance injectors, you can run low impedance but should have a peak and hold driver fitted.

Cosworth injectors are low impedance, VXR are high.

Good luck

Rob,

series_one_rst

extra efi built it and was under impression the cossie injectors i had could cope so had the driver installed.

now looking to put bigger injectors in that will cope with current cvh till it pops then my zetec turbo i'm looking at doing as and when.

Chip

iTrader: (3)

You'll need to have the driver removed or bypassed to run high impedance.

You could just get a set of green cossie injectors?

Rob_DOHC

iTrader: (4)

As above, are you sure it has an internal driver rather than external resistors? This is also a common thing to do, albeit a little wrong.

Your ecu will drive low impedance injectors with out drivers etc, its just not good for the ecu or the injectors, so you may not even have a driver installed?

If you take the lid off your ecu and post a picture up on here we will be able to tell you.

Rob,

series_one_rst

greens are an option but hear the dekas etc have better spray patterns and idle smoother iirc.

phil ringwood built it so presume its all above board. will dig it out tomorrow and get some pics. cheers lads.

Rob_DOHC

iTrader: (4)

Yes it will be above board if its one of his, if you bought it direct from him. If you have bought it second hand there could be no telling what someone's done to it.

Greens are fine, but if you want high impedance injectors the mods are very simple.

Traditionally there are certain advantages to low z injectors, however high z injectors are getting so good these days the advantages low z injectors held are no longer totally valid. Bosch EV14's are supposedly very good, as are the dekas.

Rob,

wedge07

i spoke to my tuner and hesaid u can put cossie injectors in using resistors, so anythings possible

Chip

iTrader: (3)

You have missed the point mate, the problem is that he has peak and hold drivers (a much better solution than just slowing them down with resistors which is a bit of a nasty setup TBH) built into the ecu to run cosworth ones, there isnt a trivial way of therefore running high impedance injectors with that setup.

A bit like wheels, if you have a wheel that sits too far in you can add a space to push it out, but if it sits too far out you cant easily add something to move it back inwards, if that makes sense?

Rob_DOHC

iTrader: (4)

In essence using resistors is a bodge, you get none of the benefits of low impedance injectors and need to buy and fit expensive(ish) resistors. The range of easily available and large high z injectors is pretty extensive. I might think of using low impedance injectors if I had an application which needed injectors over 1000cc/min....

The correct method as chip says to use low impedance injectors with MS is to use a peak and hold driver board.

Megasquirt can actually drive low impedance injectors directly, you will need to use 2 more injector drivers though, each transistor is man enough for one low z injector or 4 high impedance injectors.


Rob,

rsmark86

iTrader: (3)

If it was set up for low then ring msd and get cossie fitment siemens injectors for £250 a set

They do 55s/ 72s/ and 83s

series_one_rst

not got round to digging ecu out yet... hopefull (fingersCrossed) have a set of vxr 480cc injectors, £80 to me cost, coming this week so for the price of them forking 250 out for lows and keeping driver seems a no brainer. on a long weekend this week so will deffo dig it out and have a go at ripping the driver out.