Murf928 SuperShark update
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From: Gone. On the Open Road
Small ID rails
Originally Posted by GoRideSno
Fatter rails would be the exact opposite of what needs to be done. Increasing the size of the rails would decrease the pressure within them...
Andy, I won't say that fatter rails are not bad. But, if they are bad, surely it cannot be for the reason you write above? We are not talking about a constant mass of gas at steady-state that obeys PV=nRT inside a rail that changes its volume dynamically.
Sure, it takes longer to build the pressure from zero to the desired pressure because more fluid mass is required by the larger plenum and the mass flow rate from the pump is more-or-less constant. But, once at the desired pressure it is a matter of mass entering vs. mass exiting.
Consider this, the passenger's side rail has about a 15-20% larger volume than does the drivers side rail. It is longer and has some extra volume inside the hose going to the front damper. It is the last cylinder on that rail too that Tim has blown the gasket in twice.
So I would say go with a skinnier rail, besides some way of raising pressure faster.
I don't buy the lower pressure argument on rail volume size though.
It may very well be that the plenum volume required to make a useful difference in managing a transient fuel pressure gradient is so great as to be impractical.
Developer
Joined: Dec 2001
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From: Horicon, WI
Fatter rails would be the exact opposite of what needs to be done. Increasing the size of the rails would decrease the pressure within them decreasing flow through the injector.
Conversely - although Porsche made the individual injector lines on the CIS cars so little - they got bye with that because they shoot continuously.
Funny how you 32v guys are swapping fuel pumps and increasing line sizes.... very, very much down the same road I am going with my track car (read: EXPERIMENTAL CAR). Our 16v Stage 1 and 2 kits have enough fuel, but the race car - I am trying to find more fuel for it as I turn up the boost.
Here's a picture of those larger fuel lines - they helped - but I think I have a "maximum flow potential" problem stemming from the ***-end of the car that I am trying to work on now.
Drifting
Joined: Feb 2002
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From: Redondo Beach, CA>>>>Atlanta,GA
Carl,
I am glad you know more than RC Engineering which is probably one of the premier FI shops in the country. EDIT: I went to their site and they claim to be the best in the world.
The Lightning rail is NOT the same size as the line to EACH injector. ALL injectors share the same rail and that rail is NO bigger than the fuel supply line in our cars. Can you not see that in the picture? END EDIT
Regardless of the firing order of the Lightning injectors, the same amount of fuel has to flow to make the same amount of power.
Maybe you could answer this. Why is it that the curves on Tim's last dyno chart posted cross at 5750 instead of 5250?
Thx,
Andy
I am glad you know more than RC Engineering which is probably one of the premier FI shops in the country. EDIT: I went to their site and they claim to be the best in the world.
The Lightning rail is NOT the same size as the line to EACH injector. ALL injectors share the same rail and that rail is NO bigger than the fuel supply line in our cars. Can you not see that in the picture? END EDIT
Regardless of the firing order of the Lightning injectors, the same amount of fuel has to flow to make the same amount of power.
Maybe you could answer this. Why is it that the curves on Tim's last dyno chart posted cross at 5750 instead of 5250?
Thx,
Andy
Last edited by GoRideSno; Aug 20, 2004 at 03:50 AM.
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Maybe it's just me, but this sure seems like a good thread for anybody planning on supercharging their car to pay close attention to what's been said.
Tim:
And you guys wonder why I don't follow this stuff or post anymore?
Carl:
You make everyone think that you're a CIS guy, and then you make a post like that stating one of the differences between sequential and batch fire EFI?
Jim:
I don't want to tell you how to do your job, but it might not be a bad idea to check your piston inventory. No matter who's right, it seems like you may very come out a winner. $$$$
Andy:
Because the charts horsepower and torque scales are different. The curves only cross at 5,250 RPM if the horsepower and torque scales are the same. You can make the curves cross at any RPM point you want, or never cross at all, if you adjust the scaling of the individual charts in the dyno software. Neither the horsepower or torque numbers change at all at any one RPM point, just the height of the curve on the fixed height chart in relation to the other curve with the different scale set to it. Depending on what data you want plotted on the same chart, you may want different scaling. You can have the software set to "Auto Scale", "Force Scaling" which makes both scales the same, or manually adjust the scales to whatever range you want. The dyno software was apparently set to "Auto Scale when Tim's chart was printed. Most of the time the dyno operators seem to leave the software set to "Force Scaling", so that those not as familiar with dynos and dyno charts aren't so easily confused. 
Well, download complete so...
Tim:
And you guys wonder why I don't follow this stuff or post anymore?
Carl:
You make everyone think that you're a CIS guy, and then you make a post like that stating one of the differences between sequential and batch fire EFI?
Jim:
I don't want to tell you how to do your job, but it might not be a bad idea to check your piston inventory. No matter who's right, it seems like you may very come out a winner. $$$$
Andy:
Originally Posted by GoRideSno
Maybe you could answer this. Why is it that the curves on Tim's last dyno chart posted cross at 5750 instead of 5250?
Well, download complete so...
Three Wheelin'
Joined: Nov 2003
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From: Los Angeles, CA
But if the equation is:
T = (5252 x HP) / RPM
At any point in time, if RPM = 5252, then it will cancel out the 5252 on top, and you are left with T = HP. That is why T and HP cross @ 5252 - because they are equal.
Are you saying that this equation is wrong?
T = (5252 x HP) / RPM
At any point in time, if RPM = 5252, then it will cancel out the 5252 on top, and you are left with T = HP. That is why T and HP cross @ 5252 - because they are equal.
Are you saying that this equation is wrong?
Developer
Joined: Dec 2001
Posts: 7,005
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From: Horicon, WI
Andy: just semantics - what I meant was "the rail is the same size as the line from the tank" I think you and I are saying the same thing.
I kinda like Jim Baileys observation about the CIS cars having a pressure accumulator and the EFI cars not - as he says, it holds about 1/2 cup of fuel under system pressure to release so there is no system "make up" lag under sudden WOT. Interesting...
About this whole volume vs. pressure conversation: a common trick engineers will use in fluid systems when it all gets too confusing is to convert the equations as if it was electricity. Use Volts (pressure) Amps (volume) and Ohms (resistance) - in almost every way, the elctrical analogy is a perfect match and will behave the same as fluids.
Can two wires - a big one and a small one - carry the same volts, but have different amp capacities? Of course.
Will the smaller wire resist a drop in voltage when the "juice" is on better than the bigger wire? Hell no.
Does this help?
I kinda like Jim Baileys observation about the CIS cars having a pressure accumulator and the EFI cars not - as he says, it holds about 1/2 cup of fuel under system pressure to release so there is no system "make up" lag under sudden WOT. Interesting...
About this whole volume vs. pressure conversation: a common trick engineers will use in fluid systems when it all gets too confusing is to convert the equations as if it was electricity. Use Volts (pressure) Amps (volume) and Ohms (resistance) - in almost every way, the elctrical analogy is a perfect match and will behave the same as fluids.
Can two wires - a big one and a small one - carry the same volts, but have different amp capacities? Of course.
Will the smaller wire resist a drop in voltage when the "juice" is on better than the bigger wire? Hell no.
Does this help?
Three Wheelin'
Joined: Nov 2001
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From: Northern Kentucky
We need a computational fluid dynamics program to really figure this one out. It is really all about mass off fluid flow, isn't it? If the pump can keep the rail fed and the lines are adequate to support that mass flow of fluid, then all will be fine. The injector needs the fuel pressure to maintain flow and the lines and pump have to be large enough to deliver that flow. I don't think this can be analyzed by looking just at the size of the lines, as the pump is an integral part of the entire system.
You could all just drop the fuel pressure down and go with a much bigger injector. Your pump and injectors will be much happier in the end!
The 5252 comes directly from the fact that there are 550ft-lbf/second in one HP and the fact that there are 2pi radians in one revolution and 60 seconds in one minute. 550/(2*3.14/60)=5252. It is a unit conversion. Perhaps we all need to start plotting in Newtom Meters and KW? In the end the highest torque across the entire range will build the most HP across the board. I'll take the setup with the higher torque across the entire RPM range any day over higher peak HP with less "average" torque.
And the boost wars continue...
You could all just drop the fuel pressure down and go with a much bigger injector. Your pump and injectors will be much happier in the end!
The 5252 comes directly from the fact that there are 550ft-lbf/second in one HP and the fact that there are 2pi radians in one revolution and 60 seconds in one minute. 550/(2*3.14/60)=5252. It is a unit conversion. Perhaps we all need to start plotting in Newtom Meters and KW? In the end the highest torque across the entire range will build the most HP across the board. I'll take the setup with the higher torque across the entire RPM range any day over higher peak HP with less "average" torque.
And the boost wars continue...
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Originally Posted by mspiegle
But if the equation is:
T = (5252 x HP) / RPM
At any point in time, if RPM = 5,252, then it will cancel out the 5,252 on top, and you are left with T = HP. That is why T and HP cross @ 5252 - because they are equal.
Are you saying that this equation is wrong?
T = (5252 x HP) / RPM
At any point in time, if RPM = 5,252, then it will cancel out the 5,252 on top, and you are left with T = HP. That is why T and HP cross @ 5252 - because they are equal.
Are you saying that this equation is wrong?
Drifting
Joined: Feb 2002
Posts: 2,015
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From: Redondo Beach, CA>>>>Atlanta,GA
Welcome back Z. It's good to see you. Every time you show up someone buys a kit from me. Come around more often and maybe I'll get this on rennlist , by rennlister, for rennlisters venture paid for one day. I guess it would be smart to commission you as I would pay it off faster. I don't think a bank would cash a check made out to someone named Z though. Who should I make the check out to? I guess I'll need to pay your Rennlist membership too. You would have to give up your name for that though.
Andy K
Andy K
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From: Green Bay Wisconsin
Originally Posted by GoRideSno
Welcome back Z. It's good to see you. Every time you show up someone buys a kit from me. Come around more often and maybe I'll get this on rennlist , by rennlister, for rennlisters venture paid for one day. I guess it would be smart to commission you as I would pay it off faster. I don't think a bank would cash a check made out to someone named Z though. Who should I make the check out to? I guess I'll need to pay your Rennlist membership too. You would have to give up your name for that though.
Andy K
Andy K
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I'm not exactly back. Someone mentioned this thead to me and said I ought to take a look, so I did since I had nothing else to do while downloading some stuff.
As long as I get that commision on kits that are sold, and not just on ones that are installed kits.
As long as I get that commision on kits that are sold, and not just on ones that are installed kits.
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From: Las Vegas
Originally Posted by GoRideSno
Welcome back Z. It's good to see you. Every time you show up someone buys a kit from me. Come around more often and maybe I'll get this on rennlist , by rennlister, for rennlisters venture paid for one day. I guess it would be smart to commission you as I would pay it off faster. I don't think a bank would cash a check made out to someone named Z though. Who should I make the check out to? I guess I'll need to pay your Rennlist membership too. You would have to give up your name for that though.
Andy K
So Andy, with all these supercharger kits that you have been selling we are all wondering when we will actually hear about someone getting one installed. I am only aware of one person on the list that was installing your "kit" and that person stopped reporting his progress over a month ago. You claim to have sold more than twice as many kits as I have and I am wondering why we haven't heard of any results yet or testimonials from any of your customers. Maybe they are just a quiet group like the FAST guys perhaps?
Welcome back Z. It's good to see you. Every time you show up someone buys a kit from me. Come around more often and maybe I'll get this on rennlist , by rennlister, for rennlisters venture paid for one day. I guess it would be smart to commission you as I would pay it off faster. I don't think a bank would cash a check made out to someone named Z though. Who should I make the check out to? I guess I'll need to pay your Rennlist membership too. You would have to give up your name for that though.
Andy K
So Andy, with all these supercharger kits that you have been selling we are all wondering when we will actually hear about someone getting one installed. I am only aware of one person on the list that was installing your "kit" and that person stopped reporting his progress over a month ago. You claim to have sold more than twice as many kits as I have and I am wondering why we haven't heard of any results yet or testimonials from any of your customers. Maybe they are just a quiet group like the FAST guys perhaps?
Guys....Guys....
Go to your nuetral corners!!
Drifting
Joined: Jul 2002
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From: Los Angeles, CA
It was bound to happen...
Obviously, the MURF kit is complete, with full instructions, testimonials, and dyno results.
Andy's kit is more of a do-it-yourself thing.
It is probably taking people longer, because of that fact.
They have to source parts, get things figured out, etc...
With the MURF setup, you just bolt it all on, and go...
But you pay for that...
People are willing to wait for Andy's parts, and wait for the instruction manual, etc, because they are saving quite a bit of money...
Obviously, the MURF kit is complete, with full instructions, testimonials, and dyno results.
Andy's kit is more of a do-it-yourself thing.
It is probably taking people longer, because of that fact.
They have to source parts, get things figured out, etc...
With the MURF setup, you just bolt it all on, and go...
But you pay for that...
People are willing to wait for Andy's parts, and wait for the instruction manual, etc, because they are saving quite a bit of money...