Mappers ... serious question trying to understand bhp per...
03-11-2003, 04:27 PM
#42
Who told you that Rene? Thats whats buggered you up 
The BSFC is a measure of thermodynamic efficiency, and there are lots of engines running around 0.40 nowadays.. YB included.
Does that help?
PS.
Dont forget the fuels specific gravity as this is also important..
The BSFC is a measure of thermodynamic efficiency, and there are lots of engines running around 0.40 nowadays.. YB included.
Does that help?
PS.
Dont forget the fuels specific gravity as this is also important..
03-11-2003, 06:11 PM
#54
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Originally Posted by Karl
Yes as Stu rightly pointed out its amazing that many folk dont realise why we use a rising rate fuel pressure regulator!
Put simply any liguid or gas will always flow from a region of high pressure to a region of lower pressure until the pressure is equalised.
If we set our fuel pressure to 4bar at atmosperic pressure then we have an effective 3 bar fuel pressure above atmospheric. For every 1 bar boost we add, we must increase the fuel pressure by the same amount in order to keep the 3 bar differential pressure.
Failure to do this will result in a diminishing injector flow rate as we increase boost!
Put simply any liguid or gas will always flow from a region of high pressure to a region of lower pressure until the pressure is equalised.
If we set our fuel pressure to 4bar at atmosperic pressure then we have an effective 3 bar fuel pressure above atmospheric. For every 1 bar boost we add, we must increase the fuel pressure by the same amount in order to keep the 3 bar differential pressure.
Failure to do this will result in a diminishing injector flow rate as we increase boost!
Just to clarify then - when you talk about a 'rising-rate' reg Karl, you mean linear rise yeah? ie. 1bar plenum boost increases fuel rail pressure by 1bar? not one of IMA's FSE rising rate >1:1 regs?
04-11-2003, 09:14 AM
#58
Professional Waffler
cracking post! 
I think I was the one who confused rene with the manifold referenced pressure reg!! Doh I should of explained how the differential pressure is always the same
I think I was the one who confused rene with the manifold referenced pressure reg!! Doh I should of explained how the differential pressure is always the same
04-11-2003, 10:03 AM
#59
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Originally Posted by GARETH_ESCCOS
cracking post!
I think I was the one who confused rene with the manifold referenced pressure reg!! Doh I should of explained how the differential pressure is always the same
I think I was the one who confused rene with the manifold referenced pressure reg!! Doh I should of explained how the differential pressure is always the same
04-11-2003, 10:03 AM
#60
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Originally Posted by JesseT
In the beginning you mentioned that you have a fuel pressure of 4 bars AT IDLE. That would result already in a 0.5 bar error.
i was talking about ABSOLUTE pressure (vac disconnected)
04-11-2003, 10:23 AM
#61
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You are really utilizing the absolute pressure and differential pressure in a confusing way. When you have a 4 bar pressure difference across the injector, that isn't a 4 bar absolute pressure. Well, anyhow I think you understood the way the injectors and the fuel pressure regulator works.
07-04-2004, 08:06 AM
#62
Testing the future
let's bring back this oldie, but goodie.
everyone says, including Karl and Stu in this very post, that YB's have rising rate fuel pressure regulators. they are saying that the fuel rail pressure is increasing with manifold pressure to produce a constant pressure difference across the injector.
well this site describes a rising rate regulator as
i don't know one way or the other as i have never put a pressure gauge on my fuel rail. i'm sure that Karl and Stu have, and therefore know exactly what the FPR is doing and how it works and i'm sure that what they have said is true.
we then have the criticism of IMA's FSE. this may well be the wrong device for doing it, but surely a rising rate FPR is a useful thing to have?
wouldn't it make sense to increase the fuel pressure at a greater rate than manifold pressure so that on boost the injectors become capable of flowing more? is this how the NMS "Gunship Stage 1 conversion" works, or is that done by an increase in the base pressure setting?
provided the fuel pump can produce enough flow at the higher pressure, is there any reason not to use a truly rising rate fuel pressure regulator? would this not be a cheap and easy way to produce more power than std injectors can normally make?
everyone says, including Karl and Stu in this very post, that YB's have rising rate fuel pressure regulators. they are saying that the fuel rail pressure is increasing with manifold pressure to produce a constant pressure difference across the injector.
well this site describes a rising rate regulator as
A RISING RATE (RR) FPR has a ratio greater than 1:1, eg 2:1, 4:1. and will increase fuel rail pressure after a certain boost point eg 12 psi and upwards. The rising rate reg will ensure rail pressure rises at a greater rate eg 2x, 4x with boost, and injectors will flow more fuel. In this case the net effective fuel pressure would be greater than the standard 3 Bar. Rising rate means fuel flow rises at a greater rate than manifold pressure. A RR FPR is suitable to increase flow from smaller injectors (to a point), or, for the case where a manufacturers non programmable computer can't compensate for big injectors at lower rpm's.
we then have the criticism of IMA's FSE. this may well be the wrong device for doing it, but surely a rising rate FPR is a useful thing to have?
wouldn't it make sense to increase the fuel pressure at a greater rate than manifold pressure so that on boost the injectors become capable of flowing more? is this how the NMS "Gunship Stage 1 conversion" works, or is that done by an increase in the base pressure setting?
provided the fuel pump can produce enough flow at the higher pressure, is there any reason not to use a truly rising rate fuel pressure regulator? would this not be a cheap and easy way to produce more power than std injectors can normally make?
07-04-2004, 08:25 AM
#63
Norris Motorsport
foreigneRS
Indeed the std regulator is a 1:1 rising rate.
Why I call it a rising rate is simply to distinguish between a normal fixed pressure regulator and one which increases fuel pressure against manifold vacuum/pressure.
Of course if we're being pedantic we should call it a manifold pressure linked fuel pressure regulator that rises and falls linearly with manifold pressure but its just how I tend to refer to them to keep things simple for folk.
In the case of regulators like the fse I still call them rising rate but refer to the different ratio rather than 1:1. (e.g. 1.2:1)
Indeed the std regulator is a 1:1 rising rate.
Why I call it a rising rate is simply to distinguish between a normal fixed pressure regulator and one which increases fuel pressure against manifold vacuum/pressure.
Of course if we're being pedantic we should call it a manifold pressure linked fuel pressure regulator that rises and falls linearly with manifold pressure but its just how I tend to refer to them to keep things simple for folk.
In the case of regulators like the fse I still call them rising rate but refer to the different ratio rather than 1:1. (e.g. 1.2:1)
07-04-2004, 08:50 AM
#65
Testing the future
thanks for the clarification Karl.
but why not use one that is both linked to manifold pressure and is rising rate so that on boost you get a higher increase in the fuel rail pressure than in the manifold? i cannot see any disadvantages, only that it must be a cheap way to extract more power out of small injectors, or controlling a reasonable flow rate at idle and low rail pressure with large injectors.
going back to the "Gunship conversion", i have read that the boost pressure has a high midrange but tails off at the top. with a RR FPR, could you not maintain a higher boost all the way to the rev limiter on std yellows?
having said that, the boost at that level is off the scale of the MAP sensor, so why not go 3 bar MAP and greens route? the cost of the greens must be more than a RR FPR? but then 'off the shelf' chips are available for 3 bar and greens i suppose, whereas the yellows with RR FPR would need custom mapping.
but why not use one that is both linked to manifold pressure and is rising rate so that on boost you get a higher increase in the fuel rail pressure than in the manifold? i cannot see any disadvantages, only that it must be a cheap way to extract more power out of small injectors, or controlling a reasonable flow rate at idle and low rail pressure with large injectors.
going back to the "Gunship conversion", i have read that the boost pressure has a high midrange but tails off at the top. with a RR FPR, could you not maintain a higher boost all the way to the rev limiter on std yellows?
having said that, the boost at that level is off the scale of the MAP sensor, so why not go 3 bar MAP and greens route? the cost of the greens must be more than a RR FPR? but then 'off the shelf' chips are available for 3 bar and greens i suppose, whereas the yellows with RR FPR would need custom mapping.
07-04-2004, 08:52 AM
#66
Plus i didnt know that its was known as An IMA FSE....must get royalties...yes they worked even when set up wrong 
For a stage 3 they are good above thru experience not theory
they are not advisable.
For a stage 3 they are good above thru experience not theory
they are not advisable.
07-04-2004, 08:57 AM
#68
Norris Motorsport
foreigners
I do every possible setup you could imagine for the cossie, the gunship conversion is simply a low cost option to get the very maximum from a std engine.
Of course I love to sell folk a set of greens and a 3bar, its all extra money in my pocket, but not everyone has enough to afford those items. As such the gunship conversion maximises the std engine for minimal costs and the results are outstanding. I would ask anyone to drive one of my gunship converted cars before commenting as they go far better than words on here describe.
I'll be watching tiff and pops at central day to see just how fast they are!
I do every possible setup you could imagine for the cossie, the gunship conversion is simply a low cost option to get the very maximum from a std engine.
Of course I love to sell folk a set of greens and a 3bar, its all extra money in my pocket, but not everyone has enough to afford those items. As such the gunship conversion maximises the std engine for minimal costs and the results are outstanding. I would ask anyone to drive one of my gunship converted cars before commenting as they go far better than words on here describe.
I'll be watching tiff and pops at central day to see just how fast they are!
07-04-2004, 09:15 AM
#71
Testing the future
Originally Posted by Karl
I do every possible setup you could imagine for the cossie, the gunship conversion is simply a low cost option to get the very maximum from a std engine.
. I'm just wondering if a little more could be done at the top end by using a RR FPR which must be relatively cheap (<100?)? You clearly have the experience to comment on this, whereas I am just mulling over ideas and would very much appreciate your input on my ideas.
maybe i'm talking complete carp and it's a stupid idea?
07-04-2004, 09:17 AM
#72
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Originally Posted by foreigneRS
I'm just wondering if a little more could be done at the top end by using a RR FPR
07-04-2004, 09:22 AM
#75
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How
They are using RR FPRs,...lol....what part am I missing then mate? (Curious!)
If you mean a different rate FPR, I'd imagine it'd need a remap to suit if it was not 1:1, which would add massive cost
Originally Posted by foreigneRS
I'm just wondering if a little more could be done at the top end by using a RR FPR
If you mean a different rate FPR, I'd imagine it'd need a remap to suit if it was not 1:1, which would add massive cost
07-04-2004, 09:26 AM
#76
Testing the future
Originally Posted by Karl
Indeed the std regulator is a 1:1 rising rate.
Why I call it a rising rate is simply to distinguish between a normal fixed pressure regulator and one which increases fuel pressure against manifold vacuum/pressure.
Of course if we're being pedantic we should call it a manifold pressure linked fuel pressure regulator that rises and falls linearly with manifold pressure but its just how I tend to refer to them to keep things simple for folk.
In the case of regulators like the fse I still call them rising rate but refer to the different ratio rather than 1:1. (e.g. 1.2:1)
Why I call it a rising rate is simply to distinguish between a normal fixed pressure regulator and one which increases fuel pressure against manifold vacuum/pressure.
Of course if we're being pedantic we should call it a manifold pressure linked fuel pressure regulator that rises and falls linearly with manifold pressure but its just how I tend to refer to them to keep things simple for folk.
In the case of regulators like the fse I still call them rising rate but refer to the different ratio rather than 1:1. (e.g. 1.2:1)
a truely rising rate reg will increase the fuel rail pressure relative to manifold pressure
alles klar?
07-04-2004, 09:28 AM
#77
Testing the future
which would add massive cost
07-04-2004, 09:28 AM
#78
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Originally Posted by foreigneRS
the fuel rail pressure on a cossie rises relative to atmosphere, but stays constant relative to manifold pressure.
a truely rising rate reg will increase the fuel rail pressure relative to manifold pressure
hmm....im confused....if im not mistaken, a weber "cossie type" FPR conforms to what you said "a treuly rising rate" one is.Ahwell, no doubt ill only be wrong, usually am made to look wrong regardless, lol...
(its the passionford way! )
07-04-2004, 09:40 AM
#79
Testing the future
i don't know phil to be honest. as i said, i've never put a pressure gauge on my rail to see what happens. i was just going by what was said by both Stu and Karl on the first page of this post
and it hasn't been changed / corrected since. 
Originally Posted by Karl
Yes as Stu rightly pointed out its amazing that many folk dont realise why we use a rising rate fuel pressure regulator!
Put simply any liguid or gas will always flow from a region of high pressure to a region of lower pressure until the pressure is equalised.
If we set our fuel pressure to 4bar at atmosperic pressure then we have an effective 3 bar fuel pressure above atmospheric. For every 1 bar boost we add, we must increase the fuel pressure by the same amount in order to keep the 3 bar differential pressure.
Failure to do this will result in a diminishing injector flow rate as we increase boost!
Put simply any liguid or gas will always flow from a region of high pressure to a region of lower pressure until the pressure is equalised.
If we set our fuel pressure to 4bar at atmosperic pressure then we have an effective 3 bar fuel pressure above atmospheric. For every 1 bar boost we add, we must increase the fuel pressure by the same amount in order to keep the 3 bar differential pressure.
Failure to do this will result in a diminishing injector flow rate as we increase boost!
07-04-2004, 09:44 AM
#80
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Originally Posted by foreigneRS
i don't know phil to be honest. as i said, i've never put a pressure gauge on my rail to see what happens. i was just going by what was said by both Stu and Karl on the first page of this post
and it hasn't been changed / corrected since.
Originally Posted by Karl
Yes as Stu rightly pointed out its amazing that many folk dont realise why we use a rising rate fuel pressure regulator!
Put simply any liguid or gas will always flow from a region of high pressure to a region of lower pressure until the pressure is equalised.
If we set our fuel pressure to 4bar at atmosperic pressure then we have an effective 3 bar fuel pressure above atmospheric. For every 1 bar boost we add, we must increase the fuel pressure by the same amount in order to keep the 3 bar differential pressure.
Failure to do this will result in a diminishing injector flow rate as we increase boost!
Put simply any liguid or gas will always flow from a region of high pressure to a region of lower pressure until the pressure is equalised.
If we set our fuel pressure to 4bar at atmosperic pressure then we have an effective 3 bar fuel pressure above atmospheric. For every 1 bar boost we add, we must increase the fuel pressure by the same amount in order to keep the 3 bar differential pressure.
Failure to do this will result in a diminishing injector flow rate as we increase boost!
Ahhh, now I know what your on about. The bit i highlighted. The thing is, Karl says we must increase it as boost rises, else fuel flow drops off, the standard FPR DOES INCREASE IT
Or so I understand.
