Highest compression on pump gas?
04-14-2005, 01:08 PM
#142
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Originally Posted by Adrenaline_Z
I never said nitrous was boost. I said it was a charge volume adder which
increases cylinder pressure. Raising effective compression by any means results
in higher cylinder pressure.
As for SBC theories applied to the LSx, it's pretty much the same deal across
the board.
Sure the LSx series has superior design that allows more potential from nitrous,
or fuel in general, but the LSx motors have not re-written the laws of physics.
Yes, I've come across rude, but when 100 people are cutting up valid facts,
it makes you a little angry ... so I'm sorry for that.
If everyone can understand that pulling timing is detrimental, then we can
agree that higher compression and nitrous isn't the best method.
First asked yourself why timing is pulled (retarded) and what happens when
you ignite the mixture later in the cycle.
You have a certain amount of charge in the cylinder and it combusts fully in
a given amount of time.
If you start ignition at 30 degrees BTDC for instance, the charge begins to
exert pressure on the piston as it rounds TDC. As the charge expands during
combustion, force continues to be applied to the piston crown.
Using that same scenario, start ignition 6 degrees later (or 24 degrees BTDC).
Now the piston is rounding TDC and going downward as the charge begins to
expand.
So...the time that the crank angle transfers the most force to the crank has
a smaller window.
My angle is: Reduce compression. Add nitrous. Add timing for more continued
force on the piston during peak crank angle degrees.
increases cylinder pressure. Raising effective compression by any means results
in higher cylinder pressure.
As for SBC theories applied to the LSx, it's pretty much the same deal across
the board.
Sure the LSx series has superior design that allows more potential from nitrous,
or fuel in general, but the LSx motors have not re-written the laws of physics.
Yes, I've come across rude, but when 100 people are cutting up valid facts,
it makes you a little angry ... so I'm sorry for that.
If everyone can understand that pulling timing is detrimental, then we can
agree that higher compression and nitrous isn't the best method.
First asked yourself why timing is pulled (retarded) and what happens when
you ignite the mixture later in the cycle.
You have a certain amount of charge in the cylinder and it combusts fully in
a given amount of time.
If you start ignition at 30 degrees BTDC for instance, the charge begins to
exert pressure on the piston as it rounds TDC. As the charge expands during
combustion, force continues to be applied to the piston crown.
Using that same scenario, start ignition 6 degrees later (or 24 degrees BTDC).
Now the piston is rounding TDC and going downward as the charge begins to
expand.
So...the time that the crank angle transfers the most force to the crank has
a smaller window.
My angle is: Reduce compression. Add nitrous. Add timing for more continued
force on the piston during peak crank angle degrees.
Several of the links you have cited contradict what you say, did you even read them? Seems like we're all doing this------>
04-14-2005, 01:36 PM
#143
TECH Senior Member
Originally Posted by Adrenaline_Z
Why is that?
EDIT: Boost is boost. Nitrous adds charge volume. Please explain the difference.
EDIT: Boost is boost. Nitrous adds charge volume. Please explain the difference.
Originally Posted by Adrenaline_Z
I never said nitrous was boost. I said it was a charge volume adder which
increases cylinder pressure. Raising effective compression by any means results
in higher cylinder pressure.
I never said nitrous was boost. I said it was a charge volume adder which
increases cylinder pressure. Raising effective compression by any means results
in higher cylinder pressure.
Nitrous Oxyde adds to charge density, not volume.
04-14-2005, 01:46 PM
#144
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a mix of many different gases, only one of them being oxygen. Nitrous adds more oxygen to the air entering the chamber. It does not increase cylinder pressure before ignition. The same volume of air enters the cylinder, under the same pressure, the only change when nitrous is added is that the percentage of oxygen in the chamber increases.
Nitrous DOES add cylinder pressure BEFORE IGNITION! Why do you think
you need to gap the plug tighter? That's just one small example
Think before you type.
None of those links contradict me. You need to read them - not me.
People wonder why I freak out?
"Boost is Boost, Nitrous is a charge volume adder. What is the difference?"
That line does not say, Nitrous is boost.
That line says Boost is Boost. Nitrous is a charge volume adder.
A few posts down from that, I clarify once again that Nitrous is not boost.
Some people only choose to read what they want, or misinterpret pretty
much everything I have said.
Both NITROUS and BOOST add cylinder pressure and increase effective compression.
What is the difference?
Last edited by Adrenaline_Z; 04-14-2005 at 01:54 PM.
04-14-2005, 02:08 PM
#145
TECH Senior Member
OK,
N/A : When intake valve opens, it sucks in a certain amount of air and fuel.
Nitrous: The same amount of air (volume) is drawn in, but now the air oxygen content is increased (same IVE, so same volume of air), that allows more fuel and a denser charge.
Boost: The amount of air (volume) is increased as per psi output of boost unit, more volume more oxygen, that allows more fuel.
So one (N2O) adds oxygen by saturation and the other (boost) by charge volume.
That is the difference between the two.
Cylinder pressures on a boost charge before ignition is way higher than a nitrous charge.
N/A : When intake valve opens, it sucks in a certain amount of air and fuel.
Nitrous: The same amount of air (volume) is drawn in, but now the air oxygen content is increased (same IVE, so same volume of air), that allows more fuel and a denser charge.
Boost: The amount of air (volume) is increased as per psi output of boost unit, more volume more oxygen, that allows more fuel.
So one (N2O) adds oxygen by saturation and the other (boost) by charge volume.
That is the difference between the two.
Cylinder pressures on a boost charge before ignition is way higher than a nitrous charge.
04-14-2005, 02:40 PM
#146
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Originally Posted by PREDATOR-Z
OK,Cylinder pressures on a boost charge before ignition is way higher than a nitrous charge.
basically u've misunderstood everything that has been posted. and u even think that the physics of engines has changed since the LS1 came around. i'm not arguing the ability of the ls1 to handle a higher compression with nitrous but that has in no way changed the ways that an engine works so the same laws of physics apply.
everyone talks about running a higher compression ratio with nitrous AND THEN PULLING TIMING AND USING RACE GAS. i could have sworn the whole question about it was not to pull any timing and to use pump gas.
the point isn't that u can run a little bit more SCR on a nitrous motor than a boost motor. can u run the same SCR on an all out NA and an all out nitrous motor with all things being equal?? the answer ur looking for at this point would be "no." i doubt anyone can find it so i'll just help u out.
the ability of the LS1 to get away with a little more SCR with juice does not mean that the way an engine works has changed. of course some ppl in here have had good answers, but not to the right questions.
somebody talked about taking advice from somebody with a fast car. how does that translate to them knowing anything. u can bullshit all u want about "oh these ppl have been on here forever and they have a really fast car." real world that means nothing. here it just means that they're your butt buddy and you wanna stick up for them. i could care less who says what, how long i've seen them post, or how fast their car is. if it's ignorant then it's ignorant and i call it like i see it.
04-14-2005, 02:52 PM
#147
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I've heard 11.5 is about the limit for pump gas (93 octane) too.
I run 10.9 right now and it runs good on 93, but most of the time I use Sunoco 94 (It's probaly only 93 anyways) just to be safe. BTW the car is tuned with 30* or 31* of timeing.
I run 10.9 right now and it runs good on 93, but most of the time I use Sunoco 94 (It's probaly only 93 anyways) just to be safe. BTW the car is tuned with 30* or 31* of timeing.
04-14-2005, 03:40 PM
#148
TECH Senior Member
Originally Posted by RoAdRaGe912
it's a good thing captain obvious showed up. it's hard to see the forest with all those trees in the way isn't it?? have u made one comment directly to what anyone has posted yet?? adrenaline was comparing NA to nitrous and you have to compare nitrous to boost?? what kind of stupid argument is this??
The whole argument started with Adrenaline's theory that on LSx motors, running low SCR with more timing and more nitrous would make more power than a high SCR motor+ N2O+ tuning.
Some of us stated that this is not the case with LSx motors and that we have experienced that LSx motors have the ability to accomodate High SCR with Nitrous.(this through tuning, fuel and forged parts)
[quote]basically u've misunderstood everything that has been posted. and u even think that the physics of engines has changed since the LS1 came around. i'm not arguing the ability of the ls1 to handle a higher compression with nitrous but that has in no way changed the ways that an engine works so the same laws of physics apply.[/quotes]
The laws have not changed but the parameters have. The biggest improvement on the LSx are the heads (design, flow, quench area etc...)
We are here in LSx forum, so we apply LSx know how.
everyone talks about running a higher compression ratio with nitrous AND THEN PULLING TIMING AND USING RACE GAS. i could have sworn the whole question about it was not to pull any timing and to use pump gas.
the point isn't that u can run a little bit more SCR on a nitrous motor than a boost motor. can u run the same SCR on an all out NA and an all out nitrous motor with all things being equal?? the answer ur looking for at this point would be "no." i doubt anyone can find it so i'll just help u out.
the ability of the LS1 to get away with a little more SCR with juice does not mean that the way an engine works has changed. of course some ppl in here have had good answers, but not to the right questions.
somebody talked about taking advice from somebody with a fast car. how does that translate to them knowing anything. u can bullshit all u want about "oh these ppl have been on here forever and they have a really fast car." real world that means nothing. here it just means that they're your butt buddy and you wanna stick up for them. i could care less who says what, how long i've seen them post, or how fast their car is. if it's ignorant then it's ignorant and i call it like i see it.
the ability of the LS1 to get away with a little more SCR with juice does not mean that the way an engine works has changed. of course some ppl in here have had good answers, but not to the right questions.
somebody talked about taking advice from somebody with a fast car. how does that translate to them knowing anything. u can bullshit all u want about "oh these ppl have been on here forever and they have a really fast car." real world that means nothing. here it just means that they're your butt buddy and you wanna stick up for them. i could care less who says what, how long i've seen them post, or how fast their car is. if it's ignorant then it's ignorant and i call it like i see it.
And you being so knowledgeable, you should see from our locations that I live 1/2 way across the world so it would be difficult to have "butt buddies in the US", of course you know where UAE is don't you??
I know what I know, not only from education but also from experience on LSx motors and I stand by everything that I've said, shoot even a N2O dealer steppedin and confirmed all.
04-14-2005, 03:59 PM
#149
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[QUOTE=PREDATOR-Z]Go back and start reading from the first thread, one by one and slowly please so you can understand most of it.
The whole argument started with Adrenaline's theory that on LSx motors, running low SCR with more timing and more nitrous would make more power than a high SCR motor+ N2O+ tuning.
Some of us stated that this is not the case with LSx motors and that we have experienced that LSx motors have the ability to accomodate High SCR with Nitrous.(this through tuning, fuel and forged parts)
by the way were is UAE?
The whole argument started with Adrenaline's theory that on LSx motors, running low SCR with more timing and more nitrous would make more power than a high SCR motor+ N2O+ tuning.
Some of us stated that this is not the case with LSx motors and that we have experienced that LSx motors have the ability to accomodate High SCR with Nitrous.(this through tuning, fuel and forged parts)
basically u've misunderstood everything that has been posted. and u even think that the physics of engines has changed since the LS1 came around. i'm not arguing the ability of the ls1 to handle a higher compression with nitrous but that has in no way changed the ways that an engine works so the same laws of physics apply.[/quotes]
The laws have not changed but the parameters have. The biggest improvement on the LSx are the heads (design, flow, quench area etc...)
We are here in LSx forum, so we apply LSx know how.
No that is not the issue.
So you're telling me that poeple on this board with fast cars that they put together are ignorant? Hmmmmmm
And you being so knowledgeable, you should see from our locations that I live 1/2 way across the world so it would be difficult to have "butt buddies in the US", of course you know where UAE is don't you??
I know what I know, not only from education but also from experience on LSx motors and I stand by everything that I've said, shoot even a N2O dealer steppedin and confirmed all.
The laws have not changed but the parameters have. The biggest improvement on the LSx are the heads (design, flow, quench area etc...)
We are here in LSx forum, so we apply LSx know how.
No that is not the issue.
So you're telling me that poeple on this board with fast cars that they put together are ignorant? Hmmmmmm
And you being so knowledgeable, you should see from our locations that I live 1/2 way across the world so it would be difficult to have "butt buddies in the US", of course you know where UAE is don't you??
I know what I know, not only from education but also from experience on LSx motors and I stand by everything that I've said, shoot even a N2O dealer steppedin and confirmed all.
04-14-2005, 04:01 PM
#150
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Predatoz,
I appreciate the reply. I can handle the logic posted.
I agree, to a certain extent.
We need to compare nitrous shot size vs. boost pressure if we're going to
be fair.
If I were to guess, 100 shot of N20 would be near 2.5 PSI of boost.
(using atmospheric pressure at sea level ~ 14.7 PSI and 90% Volumetric Efficiency as our references).
At least now we can agree with some intellect that there IS a pressure increase
before ignition!
I appreciate the reply. I can handle the logic posted.
Cylinder pressures on a boost charge before ignition is way higher than a nitrous charge.
We need to compare nitrous shot size vs. boost pressure if we're going to
be fair.
If I were to guess, 100 shot of N20 would be near 2.5 PSI of boost.
(using atmospheric pressure at sea level ~ 14.7 PSI and 90% Volumetric Efficiency as our references).
At least now we can agree with some intellect that there IS a pressure increase
before ignition!
04-14-2005, 04:49 PM
#152
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This is not to start an argument but why dont I see bost then on my vaccuum gauge when I spray 150 shot? There isnt more air persay going in the cylinfer there is just more oxygen molecules packed tighter together. The nitrogen in nitrous oxide is just to keep temps down since the oxygen burns so hot
04-14-2005, 05:05 PM
#154
TECH Senior Member
Originally Posted by 97M6Formula
The nitrogen in nitrous oxide is just to keep temps down since the oxygen burns so hot
04-15-2005, 12:32 AM
#156
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Originally Posted by Adrenaline_Z
How dumb is this quote:
I have never seen such a bogus formula before. Did
you make that up with your alphabet soup last night?
The basic formula for combustion looks something like this:
"The chemical stoichiometric combustion of hydrocarbons with oxygen can be
written as:
CxHy + (x + (y/4))O2 -> xCO2 + (y/2)H2O
"
Originally Posted by 5-7
Octane Combustion
C8H18 + 12.5O2 --> 8CO2 + 9H2O
C8H18 + 12.5O2 --> 8CO2 + 9H2O
you make that up with your alphabet soup last night?
The basic formula for combustion looks something like this:
"The chemical stoichiometric combustion of hydrocarbons with oxygen can be
written as:
CxHy + (x + (y/4))O2 -> xCO2 + (y/2)H2O
"
He is using x=8, y=18...so plug that into your formula...
C8H18 + (8 + (18/4))O2 --> 8CO2 + (18/2)H2O
which reduces to
C8H18 + (8 + 4.5)O2 --> 8CO2 + (9)H2O
which further reduces to
C8H18 + 12.5O2 --> 8CO2 + 9H2O
04-15-2005, 08:09 AM
#158
6600 rpm clutch dump of death Administrator
I suggest some of you read this thread
https://ls1tech.com/forums/advanced-engineering-tech/254868-ignition-timing-101-a.html
if you want to discuss the hows and whys of ignition timing. There is information about the differences in Gen I SBC ignition timing vs GenIII ingnition timing.
Plus there is just some good basic info on ignition timing.
Here are the cliff notes: More isn't always better....
https://ls1tech.com/forums/advanced-engineering-tech/254868-ignition-timing-101-a.html
if you want to discuss the hows and whys of ignition timing. There is information about the differences in Gen I SBC ignition timing vs GenIII ingnition timing.
Plus there is just some good basic info on ignition timing.
Here are the cliff notes: More isn't always better....
