Injectors

[Fume Troll]

What sort are they?

Has anyone had theirs cleaned, I was looking at sending them to a postal ASNU servicer. Any reccomendations?

Cheers,

FT.

[tail slide]

They are Lucas twin-jet items. Ok but spray pattern/volume often differs between injectors and changes over time; a proper flow/pattern check would be a good idea.

For info. Mark Adams is researching a Bosch equivalent for S6's that is higher quality & better atomisation, which has taken some time to match up; we should be dyno-testing it on mine next weekend.

[Fume Troll]

Thanks. Got them off last night (what a hassle!). They look clean but I think I'll send them off to get the volume and pattern checked anyway.

Cheers,

FT.

[VARLEYHYD]

On this subject, to help reduce high fuel temp atomisation;
Also cures hot engine non-starts

Replace the fuel rail stand-off spacers on throttle bodies with a tuffnol or similar

G

[Fume Troll]

Sounds like a good idea. Might be a good excuse to use titanium bolts too!

Any tips for re-fitting the injectors? Mine seem unduly hard to replace in the fuel rail - fitting the lower end is no problem but the top o-rings are quite resistant to being pushed back into the rail.

Cheers,

FT.

[andyoleary]

VARLEYHYD said:

On this subject, to help reduce high fuel temp atomisation;
Also cures hot engine non-starts

Replace the fuel rail stand-off spacers on throttle bodies with a tuffnol or similar

G

Graham - can you elaborate on that a little please? Sounds interesting...is this to prevent heat-soak up to the rail?

Thanks

Andy

[Fume Troll]

andyoleary said:

VARLEYHYD said:

On this subject, to help reduce high fuel temp atomisation;
Also cures hot engine non-starts

Replace the fuel rail stand-off spacers on throttle bodies with a tuffnol or similar

G

Graham - can you elaborate on that a little please? Sounds interesting...is this to prevent heat-soak up to the rail?

Thanks

Andy

Got my brother to make some of these up last night... will post up some pictures.

Cheers,

FT.

[Fume Troll]

Oh and another thing - re-fitting the injectors and fuel rail. Not sure what it is like on the other S6 engineed cars, but on the Tuscan it is a tight squeeze to take the injectors out with the engine in the car. The rear fuel rail cap screw hits the underside of the bulkhead just under the windscreen when which means it can't be removed until the rail is tilted back to allow the injectors out.

Refitting is the reverse. Unless like me your forget the above, and once all the injectors are in and the rail is seated you try to get the screw back in...and can't . Then you remove them all, fit the screw through the rail, refit all the injectors and the rail. Then realise that you also can't get the spacer in! Remove it all again....

So the long and the short of it is - fit the rear screw and its spacer in the rail at the same time as you fit the injectors, not afterwards! The other screws and spacers can be put in with the rail fitted.

You live and learn!

Cheers,

FT.

[Fume Troll]

Another thing - has anyone considered chamfering the edges of the holes in the fuel rail where the injectors are inserted? The edge on mine is square which makes squeezing the o-rings in much harder than it needs to be, as well as increasing the chances of damaging an o-ring.

I've got to take the rail off again to fit my Tufnol spacers anyhow, so I think I might do this.

Cheers,

FT.

[tail slide]

Sorry to hear your trials FT, had same awkward job trialling different injectors at Austec's yesterday. For anyone else doing this, best to do after engine has cooled for hour or so - even after 30mins the fuel in the rail was still hot/pressurised and gave us an early bath!

The Bosch injectors work well though, allowed finer mapping than Lucas and probably partly responsible for higher than usual torque we saw through mid range.

BTW where do you get appropriate sized tufnol?

[Fume Troll]

tail slide said:

The Bosch injectors work well though, allowed finer mapping than Lucas and probably partly responsible for higher than usual torque we saw through mid range.

Sounds interesting!

tail slide said:

BTW where do you get appropriate sized tufnol?

I sort of cheated, my brother is an aero engine fitter.... Was looking at this place : http://www.theplasticshop.co.uk/ but haven't used them.

You only need about 6" of material. You can buy tube but we used rod and drilled it as that's what was available. Mine were 30mm long, 13.5mm OD, 8mm ID.

Cheers,

FT.

[tail slide]

Thanks for that!

[Night Rider]

Can someone post some part numbers for the Lucas & Bosch injectors? Tail Slide, how has the car been running with the new injectors. I am looking at pulling mine out and giving them the once over. But if I can buy better ones that would be an option.

Cheers

[tail slide]

Night Rider said:

Can someone post some part numbers for the Lucas & Bosch injectors? Tail Slide, how has the car been running with the new injectors. I am looking at pulling mine out and giving them the once over. But if I can buy better ones that would be an option.

Cheers

Running very well, and also economically at part-throttle; apparently more precise fuel delivery and keep settings for longer than the more basic Lucas type BUT do require re-mapping fully on dyno as their fuel delivery characteristics are different.

Bosch Type III 'light grey' No. 0 280 156 095, rated at a nominal flow of 275cc/min

I don't have part codes for Lucas.

[trackcar]

275cc/min doesnt sound anywhere near enough for a 400hp 6 cylinder engine .. more like 440cc/min needed methinks. I use 330cc/min injectors on the cerbie 4.5 and thats spread over 8 injectors. Are you sure you got the right numbers there unless the fow rate you quote is at some ridiculously low fuel pressure rather than the 43 psi most people seem to quote at? Even allowing for a 3.5 bar regulator that'd still mean 380cc/min

Edited by trackcar on Tuesday 28th October 21:08

[tail slide]

trackcar said:

275cc/min doesnt sound anywhere near enough for a 400hp 6 cylinder engine .. more like 440cc/min needed methinks. I use 330cc/min injectors on the cerbie 4.5 and thats spread over 8 injectors. Are you sure you got the right numbers there unless the fow rate you quote is at some ridiculously low fuel pressure rather than the 43 psi most people seem to quote at? Even allowing for a 3.5 bar regulator that'd still mean 380cc/min

Edited by trackcar on Tuesday 28th October 21:08

Interesting Jools - info is off Mark's invoice - I'll double check tomorrow with my friend who's a Bosch agent.

[S5TVR]

tail slide,

Have you any info on power/torque before and after the new injectors were fitted - does the car feel any different to drive ?

[tail slide]

S5TVR said:

tail slide,

Have you any info on power/torque before and after the new injectors were fitted - does the car feel any different to drive ?

Sorry, dyno mapping at Austec was after a lot of other mods as well by Dulfords, so was very different. It made most mid-range torque than Paul has seen from an S6 but less peak power, which is what the spec was supposed to do

As I understand it ... someone will be along momentarily if I'm not quite right.. ....

....there would be very little full-throttle power difference between injectors if they were working exactly as they should and were correctly mapped throughout rev range. Higher spec injectors are just more consistent and the Bosch ones also deliver a finer atomised spray, which would help more with part-throttle power and economy, and consistent burn throughout the combustion chamber (less likelihood of poor combustion/hot spots etc).

BTW Trackcar - 275 is right spec, also run on 600bhp V8's so should be good up to 450bhp S6, but I think disparity is down to different atomisation etc. As it happens we're in process of dialling out a slight full throttle 'pink' this weekend, that the Knocklite is picking up, so we'll be double-checking the advance & fuelling, as something needs correcting.

Edited by tail slide on Wednesday 29th October 19:07

[trackcar]

http://www.injectorcleaning.co.uk/flow.htm lists those injectors at 315cc/min at 3 bar so that'd be about 365cc/min at 3.5 bar (a commonly used higher regulator pressure). 365cc/min would be good for 380bhp at 90% duty cycle so they sound absolutely right on their limit if you take the published value for their flow rate rather than what you have on your invoice, and run them at 3.5bar. Not much headroom at 90% duty though. Will be interesting to see what happens if you push the spec of your engine any further.

[GreenV8S]

trackcar said:

315cc/min at 3 bar so that'd be about 365cc/min at 3.5 bar (a commonly used higher regulator pressure).

Is that assuming flow proportional to pressure?