Injectors

Having examined my (not very) new injectors they need a clean.....anyone have any special tips as to the best way to go about it and substances to use?

I doubt it's possible to DIY effectively .

http://injectorcleaning.com/

Or fit them and run a cleaner thro .

Peter - I don't know if you saw my previous question in the other post but are you sure they're 191cc injectors from a Cosworth?

I could be wrong but that seems very small for a 4 cylinder Cosworth - (191 / 5) x 4 = 153bhp approx ?

You've got 6 so therefore 230bhp but I was just more concerned that they're not much larger than you think and you'll end up in the situation you were in before, running too rich.

Have you looked up the manufacturer part number and checked the rate? There are a few sites ie http://www.wolfems.com.au/support/injectorflow

Also check that they're low impedance with a multi-meter!

You can do DIY cleaning with solution and a compressor to blast some air through but you have to set the injectors to open and squirt it through in the correct direction. I can't find the exact instructions right now but Google should help. It should be very cheap though to get them cleaned ultra-sonically and at least that way they are tested and certified.

He meant their from a guy that sold Cosworth injectors....

The standard injectors on an Alpine are 185cc, these are 191's (same as what us used on the Lemans)

You can check all injector part numbers on here

www.alpinerenaulttuning.co.uk/injector.htm

The old rule of thumb rate for flow rate / 5 has to be adjusted for turbo cars.

That rate is taken at 3 bar fuel pressure.

The GTA runs 3.2 at 0 vacuum, plus 1psi of fuel pressure for every psi of boost pressure, so the 191cc injectors work out at 229cc/min at that fuel pressure if you are running 15-16 psi of boost...

..which in theory is good for 275bhp

As for DIY cleaning in the past, the only thing ive done is fit them to a spare fuel rail, plumbed to a 12v fuel pump sucking from a bucket of neat injector cleaner, and then apply voltage to the injectors to hold them wide open (not for too long though)

Proper cleaning centres work a bit like this, but each injector squirts fuel into containers so you can see which injector is down or up on the rest of them..

Will give it a whirl! hopefully they'll solve the mini misfire Ive got!

[Alpineandy]

Some people that clean injectors (the one I saw) used clear plastic for them to 'spray' into. Of the set of diesel ones that he was trying to clean for my mate, one had a very odd spray pattern which he said may be the reason that the motor sounded very 'big endy'. After changing the injector for another 2nd hand one, the noise dissappeared.
I seem to remember it was very cheap to get them cleaned.