BOSCH INJECTOR ADVICE

BOSCH INJECTOR ADVICE

Author
Discussion

s3c chris

Original Poster:

288 posts

133 months

Saturday 17th August 2019
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Hi all.

In anticipation of some future work on my “500” RV8, I am keen to source some Bosch injectors to replace the standard Lucas ones.
I have read many threads and there doesn’t seem to be a definitive answer to the flow that is required.
The engine will be very mildly tuned, possibly a Stealth cam, (MC1 currently) ACT trumpets and hopefully GEMS engine management.
I know the Vectra injectors are used a lot but these are getting harder to obtain and I like the idea of the Bosch ones.
Can I assume a flow rate of around 250cc ( same as the Vectra ones) would be suitable?
Apparently there are Bosch EV1 types available with 264cc flow rates or would the “normal” Bosch injectors with a 215cc flow rate be adequate?
Any advice would be appreciated thank you.

Regards Chris.

ChimpOnGas

9,637 posts

182 months

Monday 19th August 2019
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Vectra injectors were supplied to Vauxhall by Seimens so they are very high quality German made twin port pintle type injectors, they are a proven direct fit for Chims and Griffs and will work perfectly with the 14CUX ECU.



I fitted a set of reconditioned Vectra injectors over 8 years ago while I was still on the Lucas 14CUX system and they worked a treat, about a year or so later I went with a Canems engine management system and simply retained them with no issues whatsoever.

Here's my post back in 2012 when I went by the name Chimpandtonic, as you'll see I cover all the spec and part numbers.

https://www.pistonheads.com/gassing/topic.asp?h=0&...

So I've been running the exact same Vectra (Siemens 5WK90761) injectors for well over 8 years now across two completely different injection systems and they're performing as good today as they did when I first fitted them.

I went to an injector cleaning specialist who supplied 8 used but fully reconditioned Vectra injectors, he tested a host of them to give me a flow matched set of 8 which he then ultrasonically cleaned and fitted new 'O' rings. With postage and VAT he charged me £160.00, which was actually cheaper than having my original existing Lucas disc type injectors reconditioned.

Without doing anything with your fuel pressure at 38psi the 250cc Vecra injectors are good for 320hp at 90% duty, up your fuel pressure to 43.5psi (3.0 Bar) and you're good right up to 343hp at the same 90% duty, so if you're staying naturally aspirated I doubt you'll need bigger.

If you're struggling to find Vectra injectors I'd have a ring around a few injector cleaning specialists, look to pay £10 each for a used Vectra injector and £10 per injector to have them cleaned and flow checked with a printout.

Here's one, so they're definitely about if you do a bit of searching.

https://www.auto24parts.com/en_GB/p/FUEL-INJECTOR-...

Or better still cleaned and tested ones from Germany, for £132.44 this seller will supply you a set of 8 cleaned Vectra injectors including delivery.

https://www.ebay.co.uk/itm/Einspritzd%C3%BCse-SIEM...

The German phrase 'Gereinigt & Geprüft' means 'Cleaned & Tested' by the way wink

Sardonicus

19,021 posts

224 months

Monday 19th August 2019
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Chris YHM

ChimpOnGas

9,637 posts

182 months

Monday 19th August 2019
quotequote all
Its important to understand the objective for a fuel injector is to break the fuel up into the smallest possible droplets as this aids atomisation which in turn aids the mixing of the fuel with the air, the smaller the particles of fuel are the better they will mix and stay suspended within the air.

Keep in mind while the Vectra injectors are plug & play for any Chimaera or Griffith owner and they are a better choice than the old 1980's tech disc type dribblers, the Vectra injectors are a twin port design which gives a wide spray angle (maybe too wide) and in two distinct jets.





https://www.youtube.com/watch?v=MVlr-mWaxrk

An RV8 TVR has a very basic 1980's period port injection inlet manifold design so you could argue the twin jet type injector nozzle design is not that well suited to our engine, twin jet injectors became commonplace in the 1990's but were really designed for four valve heads where each jet was specifically angled to a specific engine, the idea was to shoot each jet directly at the back of each of the two inlet valves.

What we really want appeared in the late 90's and early 2000's, ie the four hole injector.



With this type of injector there are not only twice as many exit ports for the fuel they are far smaller too, however each hole isn't designed to shoot four distinct jets as the twin hole shoots two. Typically operating at higher injection pressures this in conjunction with the four smaller holes helps break up the fuel way better.



What you end up with is shown above, the four hole injector gives a lovely atomised spray pattern which is exactly what we want, the trouble with fitting twin hole twin jet type Vectra injectors in our Chims & Griffs is they just fire the two jets at the walls of our inlet manifold which is actually less than ideal especially for good cold starts as the fuel already wants to condense and so stick the cold walls of the inlet manifold.

The twin hole twin jet pintle type Vecra injectors are definitely better than the disc type Lucas dribblers but if you can find a set of four hole type injectors with the right flow an impedance I would say they would be the perfect choice, especially if you ran them at higher pressure for optimal atomisation.


USChimaera

16 posts

43 months

Monday 24th June
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93 Chimaera 430 7 cylinder because one injector is not working. Noid light shows good power but may be clogged. I want to change the injectors and was wondering if anyone has found a 4 port injector that has worked in a Chimaera?

Italian450

96 posts

90 months

Tuesday 25th June
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Check out this post - these injectors work fine for me on my 450 cat.

https://www.pistonheads.com/gassing/topic.asp?h=0&...

Sardonicus

19,021 posts

224 months

Tuesday 25th June
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Any high impedance inj will work with the Lucas Hotwire system (body dimensions accepted) its the metering specs that will trip you up however , not an issue if your on an aftermarket ECU