Modifications to my V70 T5...

>Hi Adam,
>
>In response to your questions:
>
>1. In my opinion, neither Volvo nor the website got it wrong.
>What figures did you use to calculate the flow rates and what
>figures did you arrive at?

Are you talking about stock cars with stock 240-250 bhp?

>2. Refer to the above.
Indeed.

>
>3. I think both have to work hand-in-hand, afterall no one
>has proven Newton wrong yet! I'm sure there are laws that
>govern combustion too.

There are. Question is, does the site take into account other aspects required for producing power?

>
>4. I'm perplexed because I never stipulated that 80% was the
>'safe' maximum for an injector, just that this is what is
>commonly recommended, by manufacturers, for optimum operation.
> It must be possible to run an injector at a higher duty cycle
>but you are the one to advise me on that since you regularly
>tune / remap cars.

It is possible, but not recommended.

>
>I assume that it is essential run duty cycles higher than 80%
>in the 350bhp / 19T cars with stock injectors so there is no
>doubt that it can be done;

That assumption is incorrect. I won't tell you the exact figures, but I can tell you for sure that I can get an 850R on stock injectors to produce 285 bhp @ wheels without maxing out the injectors and still running the engine slightly rich. If I can do this on the stock 850R injectors, rest assured the duty cycles are even lower on the later cars.

Adam.

[pyaap]

Yes, stock cars / power since that is what you say is unattainable.

>Yes, stock cars / power since that is what you say is
>unattainable.

I didn't say this - the web site says this! Here's an example -

850R on 350 cc injectors -

Desired power = 250 bhp
Injectors = 5
BSFC = 0.65
Max Duty Cycle = 80% (0.8)
Fuel Pressure = 45 psi

The calculation says I need 420 cc injectors to produce 250 bhp. In that case, the 350 cc injectors will fall well short.

Now, unless I'm using the web site incorrectly, the figures just don't stack up.

Adam.

[pyaap]

>>Yes, stock cars / power since that is what you say is
>>unattainable.
>
>I didn't say this - the web site says this! Here's an example
>-
>
>850R on 350 cc injectors -
>
>Desired power = 250 bhp
>Injectors = 5
>BSFC = 0.65
>Max Duty Cycle = 80% (0.8)
>Fuel Pressure = 45 psi
>
>The calculation says I need 420 cc injectors to produce 250
>bhp. In that case, the 350 cc injectors will fall well short.
>
>Now, unless I'm using the web site incorrectly, the figures
>just don't stack up.
>
>Adam.


Is the fuel pressure of 45psi that you're using under maximum boost?

>
>Is the fuel pressure of 45psi that you're using under full
>boost?
>

That appears to be irrelevant to the outcome of this equation -

To run 250 bhp on the 850R according to the web site I would need a fuel pressure of 65 psi. Assuming that I have 65 psi, I still have zero room for tuning by TME ECU upgrade only to 280 bhp, or even a bleed valve!

Adam.

[pyaap]

>>
>>Is the fuel pressure of 45psi that you're using under full
>>boost?
>>
>
>That appears to be irrelevant to the outcome of this equation
>-
>
>To run 250 bhp on the 850R according to the web site I would
>need a fuel pressure of 65 psi. Assuming that I have 65 psi, I
>still have zero room for tuning by TME ECU upgrade only to 280
>bhp.
>
>Adam.

On the contrary Adam, I think it is very relevant and equally important because using the correct fuel pressure values makes a whole world of difference to the calculations and gives the website in question substantially more credibility than you have; afterall, they have been designing and manufacturing fuel injectors for a great many years so they can't be all that wrong. I'm no expert, but I think that at maximum boost, fuel rail pressure should most probably lie anywhere between 58psi and 63psi (whether its TME / BSR / RICA etc.) and that coupled the stock range of duty cycles used by Volvo, and the prudent increase of duty cycle following an ECU upgrade would mean:

1. the website 'calculator' suggests that the stock injectors of both sizes that you have quoted would be adequate for their stock applications,

and

2. quoted upgrade figures of 280bhp (TME) and 310bhp (RICA) which you have quoted earlier are attainable with stock injectors (395cc/min) on a T5. Based on these very same calculations, the TME upgrade should be using a duty cycle close to the recommended 80% and the RICA would use a "possible" duty cycle of closer to 90%.

Similarly, on an 850R with stock 350cc/min injectors, 280bhp will be attainable with 90% duty cycle whilst 310bhp would mean the injectors are virtually running at 100% (could this be why TME recommend larger injectors for certain applications).

There could, of course, be other variables involved (e.g. air-fuel ratio etc.) to get the quoted power, but it remains to be seen whether these figures are altered by very much and it is unfortunate that there is not much more information on this.

[Traduk]

This thread looked as though it was going to prove interesting and perhaps add something of worth to the prior discussion on water injection. My interest was in the area of fuel dumping for cooling purposes on WOT which would be somewhat in doubt if the injectors were maxed for performance.

On the assumption that my T5 ('99 V70) fuel rail is pressured at 3 BAR (Volvo use other pressures but 3 BAR appears the most common)then according to the two sites I should be running 402cc or 409.5cc injectors for stock performance (240BHP).

Either Volvo have had it wrong since day one or both those sites have calculators designed to make it look as though factory fitments are wrong. I think that I will put my faith in Volvo especially as the site calculators are wrong with the first basic calculation on manufacturers fitments.

>On the contrary Adam, I think it is very relevant and equally
>important because using the correct fuel pressure values makes
>a whole world of difference to the calculations and gives the
>website in question substantially more credibility than you
>have; afterall, they have been designing and manufacturing
>fuel injectors for a great many years so they can't be all
>that wrong. I'm no expert, but I think that at maximum boost,
>fuel rail pressure should most probably lie anywhere between
>58psi and 63psi (whether its TME / BSR / RICA etc.) and that
>coupled the stock range of duty cycles used by Volvo, and the
>prudent increase of duty cycle following an ECU upgrade would
>mean:
>
>1. the website 'calculator' suggests that the stock injectors
>of both sizes that you have quoted would be adequate for their
>stock applications,

Not if you plug the numbers in. At 53 psi, the stock injector on an 850R has a shortfall of 37 cc/min for stock 250 bhp, and has no shortfall at 65 psi for stock 250 bhp. Now, these values are for 80% duty cycle, for which I've already stated that going much further is not recommended, so bleed valve, TME, RICA would all be completely out of the question if this web site was right.

>
>and
>
>2. quoted upgrade figures of 280bhp (TME) and 310bhp (RICA)
>which you have quoted earlier are attainable with stock
>injectors (395cc/min) on a T5. Based on these very same
>calculations, the TME upgrade should be using a duty cycle
>close to the recommended 80% and the RICA would use a
>"possible" duty cycle of closer to 90%.
>
>Similarly, on an 850R with stock 350cc/min injectors, 280bhp
>will be attainable with 90% duty cycle whilst 310bhp would
>mean the injectors are virtually running at 100% (could this
>be why TME recommend larger injectors for certain
>applications).

You are basing your comments on a web site calculation, for which it actually specifies their own injectors in the equation. I am basing my comments on expereince. I've already stated that I can get an 850R on stock injectors to run 285 wheel hp without maxing out the injectors. This isn't theory. It's fact. So if I can do it on the 19T, I can certainly do lower power figures on the stock turbo, and even more so on the later cars, without maxing out the injectors.

>
>There could, of course, be other variables involved (e.g.
>air-fuel ratio etc.) to get the quoted power, but it remains
>to be seen whether these figures are altered by very much and
>it is unfortunate that there is not much more information on
>this.

True, and to be honest I think this is highly likely and probably where the calculations are falling over. It's possibly why their equation specifies their own injectors.

Adam.

The bottom line is that many such web sites are fundamentally flawed, in that there is clearly not enough data to make an informed and calculated decision. Therefore making a tuning decision based on the results of such web calculations like these is not very wise in my opinion, because at best you will end up spending more money on tuning than you have to, and at worst you will break something.

However, from experience (which to me is far more valuable than any web site) I can tell you that most 19T upgrades don't need larger injectors.

Adam.

>Either Volvo have had it wrong since day one or both those
>sites have calculators designed to make it look as though
>factory fitments are wrong. I think that I will put my faith
>in Volvo especially as the site calculators are wrong with the
>first basic calculation on manufacturers fitments.

I would tend to agree.

Adam.