Flow checked my injectors

[ridds]

As they're out I thought I'd Sonic bath them, flow check and replace the injectors.

Amazingly they were well matched currently as it is, 2-3cc's difference bank to bank with 1cc between they cylinders on each bank.

As for the spray pattern, well I wouldn't call it a spray more of a jet.

[Steve_T]

Good old Lucas ones then eh!

[ridds]

Pattern pretty much like number 5 here.

[HarryW]

ridds said:

Pattern pretty much like number 5 here.

That's about the normal pattern for standard hose pipes, you can just see them putting out those pesky flames in the cylinder . Ideally something like No6 is best, but a finer mist again will improve the beastie, which spookily enough is just like my replacement ones. They actually are lower rated than the original ones, just shows big numbers are not necessarily best when it comes to injector flow rates .

[trackcar]

Interstingly I've tried some bosch injectors in a cerbera 4.5 and it made 390hp, exactly what it made on the std injectors. Ive also tried many sets now in RV8 engines and they've all lost power seems to be about 3% down on average over a lucas injector car. Driveability and emmisions are much improved on cars with wild cams, but the hp dropped every single time.

[HarryW]

trackcar said:

Interstingly I've tried some bosch injectors in a cerbera 4.5 and it made 390hp, exactly what it made on the std injectors. Ive also tried many sets now in RV8 engines and they've all lost power seems to be about 3% down on average over a lucas injector car. Driveability and emmisions are much improved on cars with wild cams, but the hp dropped every single time.

Thats interesting Joolz, there are a lot of different injectors you can use that are no better than the standard lucas hosing orignals, some of which will be bosch ones.
Raw peak power figures aside what did the car drive like as response and manners are probably the biggest winners for me, it certainly smoothed out the light throttle driving. Did you see a change in the torque

[julian64]

This is why I like jools.

Thread Theory theory theory.

Jools 'In practice thats boocks'

Aint life fun that its easier to fit the theory to the practice than the other way round.

I would so love to do your job jools, anytime you want to swap for a couple of months.

[trackcar]

Well I've talked thi over with a few people now and the way it seems to be working on the RV8s that i've tried them on is similar in my mind to the old A series engines ..

I remember david vizard (i don't think anyone would argue with his credentials ) saying that on the A series the injection gave the lowest hp, the dellorto carb (with a droplet size slightly larger) gave the next lowest and the weber (with the largest fuel droplet size of the three) gave the best hp ..

so at the mo I'm thinking that the RV8 is behaving the same way as an A series as regards it's response to droplet sizing. Yes I know the two engines are fundamentally different, but in my testing so far they appear to behave in the same way.
The injectors i've been using are the red top b-302.

Driveability on the race cammed engine was much improved and it didnt sting my eyes if i stood round the back of the car with the engine running .. driveability etc on the lesser cammed cars didn't appear to change much, but then i run full management so i get to optimise for the lucas injector anyway, if you're sticking with clockwork distributor you probably need more help on getting driveability so in those cases a finer droplet mist might help, but I can't say for certain as i've never tried it with a dizzy.

[HarryW]

julian64 said:

This is why I like jools.

Thread Theory theory theory.

Jools 'In practice thats boocks'

Aint life fun that its easier to fit the theory to the practice than the other way round.

I would so love to do your job jools, anytime you want to swap for a couple of months.

I think you are confusing the issue here, with the inference being no other injector is better than the TVR original specified one. You do realise that TVR would have thrown the cheapest one that sort of did the job in the first place don't you .
I happen to like the... have theory, try it out, if it works for you good if it doesn't try again but diferrently.
The beauty of Vizzard is it is always backed up by experience but eh seed is always a theory (He's a good friend with David the engine builder at Austec btw).
Joolz emulates this approach which is good and sensible, to dismiss things that don't work for you as boocks is akin to taking your ball home when you don't score a goal in the playgound.

Joolz careful with 'Red tops' there is more than one version going under the banner.

Forgot to mention the other benfit is a better and more economical burn which if you are knocking out at least the same performance will pay for itself in no time at all given the current price of go go juice .

[julian64]

I think you misunderstand Harry. I don't think jools was in the slightest telling anyone they were talking boocks, neither was I. I like the chat regarding engine improvement, and I'm sure jools does too as he seems to manage to make a profit doing it full time.
Defo my favourite even though my engine has been apart then put back together, then all of the top of my engine has had me flowing it with my little dremel. Six weeks just to find TDC on the engine to my satisfaction. Not once in all of that have I ever had my engine on a dyno either before or after.

I just like the northerner way jools seems to post. 'bloody done that and it twas no bloody good'. No faffing around.

I spent ages trying to get my tappet shims and timing on my cam absolutely spot on. Talked about it endlessly on this forum. The day I had finally put gasket sealent on the rocker covers and got the whole bastard air tube thing back in place jools comments on my thread 'Of course I never bloody use standard shim settings as their no bloody good'

Its a dead heat for me which poster makes me laugh the most out of him and SXS.

(Not for the same reasons I might add )

[HarryW]

Good, we are saying the same thing then, no gains = its not repeated, but at least you get to know which theory works. I stand by mine was a pig without the injector change, perhaps the different state of tune or injector positioning of the 4.2 intake makes the difference in my case, but make a difference it did. What with the exchange rate still being healthy with the US they are not overly expensive at present.
Another way to look at it is if it makes a 5%-10% difference to the fuel economy I read that as a 5%-10% fuel bill saving which at say £50 a weekend blatting fuel bill it would take less than a year to recoup its outlay. Over the coming years its going towards making your next upgrade virtually free convinced myself there

[julian64]

Never understood this. Is there a difference between fuel economy and power. Surely you can't have one without the other.

If you improve combustion in an engine in whatever way you can then choose to have that improved performance in economy or power depending on your mapping?

[GreenV8S]

julian64 said:

Never understood this. Is there a difference between fuel economy and power. Surely you can't have one without the other.

If you improve combustion in an engine in whatever way you can then choose to have that improved performance in economy or power depending on your mapping?

A change to the physical characteristics of the engine (injector droplet size, for example) might have effects that improve power output under peak power conditions (increased valve cooling or whatever) but degrade fuel economy under light load conditions (fuel air mix less well prepared leading to less even burn).

[julian64]

GreenV8S said:

julian64 said:

Never understood this. Is there a difference between fuel economy and power. Surely you can't have one without the other.

If you improve combustion in an engine in whatever way you can then choose to have that improved performance in economy or power depending on your mapping?

A change to the physical characteristics of the engine (injector droplet size, for example) might have effects that improve power output under peak power conditions (increased valve cooling or whatever) but degrade fuel economy under light load conditions (fuel air mix less well prepared leading to less even burn).

Isn't that a torque vs power argument, when actually torque is power just described at a different point on the rev range?

Again I could be talking boocks cos I don't think I've really ever understood this

[350Matt]

Interestingly my experience of injectors is that generally the smaller the droplet size the better the power output, however in all injectors I tested the benefits were only apparent when the injection timing map was changed to optimise. Sometimes the fuel mix needed changing as well as the spark timing.


So I'd say with a batch fired engine there's probably so much fuel washing around at any one time whatever the droplet size was to start with probably doesn't matter much.

Have you had a the chance to try sequential injection on a Cerb yet Jools?

Matt

[GreenV8S]

The fact that performance on carbs is known to vary with droplet size suggests that droplet size has a direct effect, separately from any issues relating to the phasing of fuel versus air. I guess that droplet size will determine how far the droplet gets before it evaporates which will determine where the evaporation occurs. I can imagine that if the evaporation happens too far from the chamber the charge will have time to absorb heat from the environment, perhaps negating some of the gains from evaporative cooling. I'm sure there are a whole load of other effects that depend on droplet size, too - particularly in an injection setup with the extra variable of the timing of the fuel delivery.

Edited by GreenV8S on Thursday 24th January 15:25

[dannylt]

Dave Walker (who does the Emerald I think Joolz uses) doesn't think sequential adds power. Having said that, it's enabled on my Caterham (for the inner 4 injectors only) so I assume it could work for the V8. One question - why are there only 6 injectors up there??? :-)

All this Cerbera tuning stuff is fantastic. I wish I still had mine to leave with Joolz, though I console myself by knowing I'd never be able to tell the difference between 400 and 420/430 bhp...

[ridds]

As that was an example image.

You can improve fuel economy and performance. If you are getting a better burn due to improved mixing etc with certain injectors (ones that don't hinder performance lol ) then you will decrease you BSFC (Brake Specific Fuel Consumption) Given fuel in over a given output, and thus reduce the amount of fuel you need to burn.

[350Matt]

dannylt said:

Dave Walker (who does the Emerald I think Joolz uses) doesn't think sequential adds power. Having said that, it's enabled on my Caterham (for the inner 4 injectors only) so I assume it could work for the V8. One question - why are there only 6 injectors up there??? :-)

It depends on the state of tune of the engine, on very highly tuned stuff it definitely adds power by highly tuned I mean 120hp+ / ltr

Matt

[julian64]

Not sure it matters what Dave at emerald says. I think it speaks for itself that the whole of BMW design department tried and dumped it because it did nothing for power and very little for economy.

No point reinventing the wheel I guess