Stroker ls1 or piston and rod ls3?
I still didn't see a power goal. But I do see an excellent opportunity to spend a bunch of money to make LESS power. How you ask? By going to a large motor with the same crap single 3 inch exhaust you'll end up with larger back pressure. As a bonus you'll have a HIGHER chance of engine damage. You don't have a stock 5.3 so you shouldn't be swapping motors more than tires if the tune is good.
You haven't begun to max your setup and could run 2 bar of boost with good fuel or more meth. Cylinder pressure spikes pop head gaskets not boost level. Your setup isn't sorted between the meth issues and pea shooter exhaust. Get the setup sorted and then talk about a bigger motor.
You haven't begun to max your setup and could run 2 bar of boost with good fuel or more meth. Cylinder pressure spikes pop head gaskets not boost level. Your setup isn't sorted between the meth issues and pea shooter exhaust. Get the setup sorted and then talk about a bigger motor.
TECH Fanatic
Joined: Dec 2019
Posts: 1,129
Likes: 478
1) nothing to do with it at all? So when the boost is being turned up and up, water starts being pushed into the cylinders or a head gasket failure occurs, the higher boost didn’t cause that? Have you been drinking? I don’t have a 5 bolt block. My block is aluminum, which I plan on staying with and I have bolts instead of studs. All of those factors fall into place that will limit the reliable boost level. Not sure how you could disagree with this, but whatever.
2) poor execution? Really? How would you like me to execute a simple 4” 90 degree silicon boot into a throttle body with a t bolt clamp? Not like I’m using a worm drive clamp on it. I’ve tried a $30 mishimoto clamp. It’s not rocket science. It doesn’t take an engineering degree to put a damn boot on a throttle body. I didn’t machine the throttle body. If I had, there would be a bigger lip like all of the other connections that I made. None of which have popped off. I can fix it, I just haven’t. I’ll chuck it up in my lathe and make a better lip and put grooves in the surface behind the lip.
3) that was a half ***, smart *** answer. I’m limited at the amount of boost I can run safely on pump 93. Is that not a fact? How many people run 20+ psi on pump gas only? So you disagree that it’s not safer to run 14-15psi with a bigger engine than it is to run 20-22 on this smaller engine. Please explain how it would not be better to lower the boost. I’m interested in that.
4) once again, take a 5.3 making 400hp. Add 15psi to it. IF everything was optimal, it SHOULD make 800ish hp. Take a ls3 that’s 500-550hp. If everything is optimal it should make 1000-1100hp. How is 200hp at the same boost not better?
and building an na setup? Where did that nonsense come from? I’d have to have a louder, way more radical combo and it wouldn’t be as fast as it is now. My setup is quiet, idles at 650rpm, gets decent fuel mileage and drives perfect. Why would I want to take two steps back? You make no sense. You just feel like arguing or something? I mean if that’s what you wanna do, it’s cool with me. I haven’t had a good argument in a while.
2) poor execution? Really? How would you like me to execute a simple 4” 90 degree silicon boot into a throttle body with a t bolt clamp? Not like I’m using a worm drive clamp on it. I’ve tried a $30 mishimoto clamp. It’s not rocket science. It doesn’t take an engineering degree to put a damn boot on a throttle body. I didn’t machine the throttle body. If I had, there would be a bigger lip like all of the other connections that I made. None of which have popped off. I can fix it, I just haven’t. I’ll chuck it up in my lathe and make a better lip and put grooves in the surface behind the lip.
3) that was a half ***, smart *** answer. I’m limited at the amount of boost I can run safely on pump 93. Is that not a fact? How many people run 20+ psi on pump gas only? So you disagree that it’s not safer to run 14-15psi with a bigger engine than it is to run 20-22 on this smaller engine. Please explain how it would not be better to lower the boost. I’m interested in that.
4) once again, take a 5.3 making 400hp. Add 15psi to it. IF everything was optimal, it SHOULD make 800ish hp. Take a ls3 that’s 500-550hp. If everything is optimal it should make 1000-1100hp. How is 200hp at the same boost not better?
and building an na setup? Where did that nonsense come from? I’d have to have a louder, way more radical combo and it wouldn’t be as fast as it is now. My setup is quiet, idles at 650rpm, gets decent fuel mileage and drives perfect. Why would I want to take two steps back? You make no sense. You just feel like arguing or something? I mean if that’s what you wanna do, it’s cool with me. I haven’t had a good argument in a while.
1.) I disagree because I'm not using highschool Honda-Tech logic. I'm interested in hearing how you think 20 PSI can lift heads.
Cylinder pressure X Bore = Force. 1000 PSI cylinder pressure X 12.56 sq-in (4" bore) = 12,560 pounds of force.
Cylinder pressure makes torque. 500 ft-lbs on a given bore size is going to be roughly the same amount of cylinder pressure whether its N/A or boosted.
Wanting to run less boost to make the same power is literally going to exert the EXACT same amount of force on the heads.
If you want, I can go into the details on why its actually MORE harmful to make X amount of torque N/A than it is with boost.
2.) The fact that you keep blowing couplers off at mild boost is simply poor execution. Even if its the fault of the parts, its still your fault for running those parts.
3.) 4 cylinders and even Supras often run 30-40 PSI on pump gas. You still haven't given me an example of how pressure itself actually deters pump gas use.
If you want to discuss heat, that's a dead end for you as well. The heat increase from compression has nothing to do with starting pressure.
A 10:1 engine with 100 degree intake temps is going to have the same final compressed temperature as a 10:1 engine with 100 degree intake temps and 20 PSI.
Heat of Compression Formula:
Pi*Vi^K=Pf*Vf^K
TemperatureIn*PressureRatio^((AirGamma-PressureIn/AirGamma))=TemperatureOut.
TempIn*(PressureRatio^((1.4-1)/1.4))=TemperatureOut
TempIn*(PressureRatio^0.2857)=TemperatureOut
Heat of compression examples:
The heat of compression difference between 9:1 and 10:1 compression with 100*F (311 Kelvin) intake temps using the formula TempIn(K)*(PressureRatio^[0.4/1.4])=TempOut(K):
9:1 Compression - 100*F In/588*F Out
10:1 Compression - 100*F In/620*F Out
32* F temperature difference with a full point of compression with chamber temps increasing from 588 to 620 using 100*F inlet temps.
By Comparison using a non-intercooled setup from your very own words:
_____________________
"Originally Posted by Forcefed86 View Post"
Either way I keep it around 60-65% and have zero issues on 19lbs without an IC... Seeing intake temps around 220-240 on a hot day.
_____________________
We'll go down a full point to 8:1.
8:1 Compression - 230*F In/787*F Out
An 8:1 non-intercooled setup has significantly more heat in the cylinder at TDC than a 10:1 compression engine with a good intercooler...
and is giving up 13% power from the 130 degree temperature difference (using the SAE J1349 formula) and apparently 10% power from the 2 points of compression.
23% loss with zero gain in knock reduction.
9:1 Compression - 100*F In/588*F Out
10:1 Compression - 100*F In/620*F Out
32* F temperature difference with a full point of compression with chamber temps increasing from 588 to 620 using 100*F inlet temps.
By Comparison using a non-intercooled setup from your very own words:
_____________________
"Originally Posted by Forcefed86 View Post"
Either way I keep it around 60-65% and have zero issues on 19lbs without an IC... Seeing intake temps around 220-240 on a hot day.
_____________________
We'll go down a full point to 8:1.
8:1 Compression - 230*F In/787*F Out
An 8:1 non-intercooled setup has significantly more heat in the cylinder at TDC than a 10:1 compression engine with a good intercooler...
and is giving up 13% power from the 130 degree temperature difference (using the SAE J1349 formula) and apparently 10% power from the 2 points of compression.
23% loss with zero gain in knock reduction.
So by my math and using basic knock rules on say pump 91 fuel. (and of course this is making a million assumptions and very general)
If the knock threshold for CC heat is say 650*...
Pump Fuel N/A Engine
100F ambient temperature
11:1 static compression ratio
Formulas above yield 644F & 162psi in the cylinder
Pump Fuel Turbo Engine
100F ambient temperature
8.5:1 static compression ratio
15psi boost intercooled
Assume 144F manifold temperature
Formulas above yield 647F & 252psi in the cylinder
So the N/A engine is near the detonation limit with pump fuel and no boost at a relatively low cyl pressure. We can't add much boost to this combination "safely",
Yet the low compression motor with a typical intercooled turbo setup can run 15lbs and still be below the knock CC temps. making 36% more cyl pressure. So does that mean detonation is more about CC temperature than pressure? If that's so, can we run all the boost we want as long as we control the peak cylinder temperature? Simply continue to dropping the SCR and raising boost as long as we stay below that knock threshold temperature of the fuel? This is assuming the bottom end can handle the power of course...
If the knock threshold for CC heat is say 650*...
Pump Fuel N/A Engine
100F ambient temperature
11:1 static compression ratio
Formulas above yield 644F & 162psi in the cylinder
Pump Fuel Turbo Engine
100F ambient temperature
8.5:1 static compression ratio
15psi boost intercooled
Assume 144F manifold temperature
Formulas above yield 647F & 252psi in the cylinder
So the N/A engine is near the detonation limit with pump fuel and no boost at a relatively low cyl pressure. We can't add much boost to this combination "safely",
Yet the low compression motor with a typical intercooled turbo setup can run 15lbs and still be below the knock CC temps. making 36% more cyl pressure. So does that mean detonation is more about CC temperature than pressure? If that's so, can we run all the boost we want as long as we control the peak cylinder temperature? Simply continue to dropping the SCR and raising boost as long as we stay below that knock threshold temperature of the fuel? This is assuming the bottom end can handle the power of course...
If you want to move into detonation from a more dense air-fuel ratio:
Boost and octane have no direct correlation to each other. I've tuned smaller engines that made 40 PSI on 93 octane before.
Higher pressure raises the boiling and flash points of gasoline.
Pressure DOES decrease the autoignition temperature, but we'll get to that at the end.
And boost being a measurement of restriction is a bit of a misunderstanding. It is a measurement of resistance on the compressor, not the engine. You could run heads/intake with 6" wide ports and a 10" throttle body that poses ZERO restriction to flow, but you're still going to be making boost if the compressor inlet is pulling in more CFM than the engine can pull in by itself.
THE MOST IMPORTANT THING: airmass determines power/torque production.
If boost was a measurement of restriction, it would be highest before the valve, and would drop afterwards once entering the cylinder.
Whether boost is 25 PSI in the intake manifold or 5 PSI in the intake manifold, if the end result is the same amount of power, its because the airmass and boost pressure in the cylinder was the same, regardless of what it was in the intake manifold (as long as the camshaft and static compression ratio are the same). Since autoignition doesn't occur in the intake manifold, pre-cylinder pressure is completely irrelevant to knock/autoignition/octane, etc. You might increase the chances of a tuning error using a wider spread of the fueling/spark tables, or complications involving excess heat, but that's easily dealt with.
Long story short, heads/intake or any other pre-cylinder flow restrictions you might have will have NO effect on chances of knock with pump gas, because the cylinder pressure will be the same for a given power level, meaning that pressure's effect on autoignition temperature doesn't apply.
You want to change something that will allow you to make more power on less boost with a direct effect on your chances of knock with pump gas? Camshafts are the exception to the rule.
Everything else, you're literally throwing your money away.
Higher pressure raises the boiling and flash points of gasoline.
Pressure DOES decrease the autoignition temperature, but we'll get to that at the end.
And boost being a measurement of restriction is a bit of a misunderstanding. It is a measurement of resistance on the compressor, not the engine. You could run heads/intake with 6" wide ports and a 10" throttle body that poses ZERO restriction to flow, but you're still going to be making boost if the compressor inlet is pulling in more CFM than the engine can pull in by itself.
THE MOST IMPORTANT THING: airmass determines power/torque production.
If boost was a measurement of restriction, it would be highest before the valve, and would drop afterwards once entering the cylinder.
Whether boost is 25 PSI in the intake manifold or 5 PSI in the intake manifold, if the end result is the same amount of power, its because the airmass and boost pressure in the cylinder was the same, regardless of what it was in the intake manifold (as long as the camshaft and static compression ratio are the same). Since autoignition doesn't occur in the intake manifold, pre-cylinder pressure is completely irrelevant to knock/autoignition/octane, etc. You might increase the chances of a tuning error using a wider spread of the fueling/spark tables, or complications involving excess heat, but that's easily dealt with.
Long story short, heads/intake or any other pre-cylinder flow restrictions you might have will have NO effect on chances of knock with pump gas, because the cylinder pressure will be the same for a given power level, meaning that pressure's effect on autoignition temperature doesn't apply.
You want to change something that will allow you to make more power on less boost with a direct effect on your chances of knock with pump gas? Camshafts are the exception to the rule.
Everything else, you're literally throwing your money away.
4.) Sure, 200 HP at the same boost is better, but I think the above explanations are enough to describe why just adding a few more PSI to the smaller engine to make the same HP makes more sense than wasting thousands of dollars for the exact same result.
Btw, do you remember that time you blindly told someone to increase their dwell time by 2 MS to solve spark issues?
I do, you got pissy when I said it was a dumb idea. Coils auto-fire when fully charged (over-dwelled). Every 0.1 milliseconds at 6000 RPM = 3.6 degrees of ignition advance.
Yeah, highschool Honda-Tech logic CONSTANTLY out of you.
I still didn't see a power goal. But I do see an excellent opportunity to spend a bunch of money to make LESS power. How you ask? By going to a large motor with the same crap single 3 inch exhaust you'll end up with larger back pressure. As a bonus you'll have a HIGHER chance of engine damage. You don't have a stock 5.3 so you shouldn't be swapping motors more than tires if the tune is good.
You haven't begun to max your setup and could run 2 bar of boost with good fuel or more meth. Cylinder pressure spikes pop head gaskets not boost level. Your setup isn't sorted between the meth issues and pea shooter exhaust. Get the setup sorted and then talk about a bigger motor.
You haven't begun to max your setup and could run 2 bar of boost with good fuel or more meth. Cylinder pressure spikes pop head gaskets not boost level. Your setup isn't sorted between the meth issues and pea shooter exhaust. Get the setup sorted and then talk about a bigger motor.
well I do t particularly have a power goal. I forgot to mention, I am planning on going bigger on the exhaust. What I have now is killing it. Going either 3.5” (I have pipe already) or 4” which would probably be the better choice for future growth. I also plan on going with a next gen or gen 2.5 turbo. I’m probably jumping the gun right now with talking about another motor, but if I come across an ls3 or l99 block cheap enough, I’ll scoop it up for later.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo Picking a goal is step 1, otherwise you'll spend money you don't need to or waste time. Just remember I picked up 30WHP at 8 psi with an electric cutout compared to a 3.5" overaxle exhaust. You've got probably 50whp in your exhaust setup and another 150whp in boost before your setup is maxxed.
9 Second Club
Joined: Nov 2003
Posts: 13,616
Likes: 185
From: Norn Iron
Well I've been toying with the idea of going to a bigger engine. Why you ask....Let me explain.
To get the power i'm wanting, i'm have to run at least 20lbs of boost. Pump gas and that much boost probably are a time bomb. I'll admit. Its going fine on 18lbs and a little bit of meth as it is. But thats just it, its going fine...till it doesnt.
I dont like having to run that much boost, brings iats up too, i'm getting nervous about my intake manifold failing, head gaskets failing and i've popped the elbow off at the throttle body too. The engine temps start climbing if I make a couple rips back to back. We all know as you go up in boost, things get riskier.
So...my thought process is I could either
A) Build the ls6 block I have with a stroker crank and maybe better heads, bigger cam and get about 383 cu.in. out of it and be able to lower the boost and it'll make just as much power on less boost and be safer doing it or
B) sell the ls6 short block, add in money and get an ls3.....however, for the same money, I wont have forged pistons, rods and crank....So I'll have to spend even more money...unless I can find a bare block and buy a rotating assembly. That little 500hp destroked 5.3 I read about in another thread sounds tempting...I like rpms.
So I'm not about to start this right away, but I would like some opinions on it. Surely i can pick up a block sooner or later if I decide to go ls3. Remember, I could take the crank out my ls6 bottom end and buy rods and pistons as $$$ permits. Or I could pick up another stock crank cheap and just sell the whole 5.7 shortblock. AND I'd be ahead power wise if I can use ls3 heads. Just dreaming right now...but it may become a reality before too long.
To get the power i'm wanting, i'm have to run at least 20lbs of boost. Pump gas and that much boost probably are a time bomb. I'll admit. Its going fine on 18lbs and a little bit of meth as it is. But thats just it, its going fine...till it doesnt.
I dont like having to run that much boost, brings iats up too, i'm getting nervous about my intake manifold failing, head gaskets failing and i've popped the elbow off at the throttle body too. The engine temps start climbing if I make a couple rips back to back. We all know as you go up in boost, things get riskier.
So...my thought process is I could either
A) Build the ls6 block I have with a stroker crank and maybe better heads, bigger cam and get about 383 cu.in. out of it and be able to lower the boost and it'll make just as much power on less boost and be safer doing it or
B) sell the ls6 short block, add in money and get an ls3.....however, for the same money, I wont have forged pistons, rods and crank....So I'll have to spend even more money...unless I can find a bare block and buy a rotating assembly. That little 500hp destroked 5.3 I read about in another thread sounds tempting...I like rpms.
So I'm not about to start this right away, but I would like some opinions on it. Surely i can pick up a block sooner or later if I decide to go ls3. Remember, I could take the crank out my ls6 bottom end and buy rods and pistons as $$$ permits. Or I could pick up another stock crank cheap and just sell the whole 5.7 shortblock. AND I'd be ahead power wise if I can use ls3 heads. Just dreaming right now...but it may become a reality before too long.
LS3 is all pros.
bigger engine, better heads ( stock ), LS3 intake is one of GM's best and of course the larger size.
Cons....you need a 24x trigger ? You need a 1x cam trigger ? Both no big deal. As well as the knock sensor mods. And you could stroke it too if need be.
20psi on pump is not an issue if CR is sensible though....but it does seem the LS3 has stronger pistons than the older LS1's so again the LS3 is a win there too even on pump.
Really, there is no need to overthink it with long winded posts and bullshit.