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You are absolutely wrong on the throttle body. I have ported them as well as I have swapped more than enough of them from 78mm to 92mm even using the stock manifold There are gains going from 3.5" intake piping to 4" intake piping even with a smaller throttle body. Same for a carburetor. More WOT power from an 850 cfm vs say a 600 cfm even on an engine that makes ~200 hp. The less pumping losses the more power.
Hahahaha hahahahahaha that's ludicrous. You SERIOUSLY have no idea what you're talking about literally whatsoever. That's so far off base that it's on its own planet.
A 200hp engine will NOT EVER make more power with a 850 than it does with a 650.
It will literally only consume what it can consume...abd at 650cfm it has more than plenty to consume. You clearly don't understand how a carb works either 😂😂😂😂😂 it needs a vacuum source(if you go too big it creates to poor vacuum signal since the air is going to travel slower through the venteri)
A 6.0 needing a 92mm throttle body hahahahaha dear lord. No. Just no.
There is no gain on a 6.0 going from a 3.5 to 4.0 tube intake. Literally none. Why? Because it doesn't need it. Porting a throttle body is minimal and nearly a wasted effort which just shows your lack of knowledge on this subject. Have you measured pressure differences? Calculated the air density? I mean the mental gymnastics you're doing is purely amazing. Explain to me.... If the throttle body is the problem how did going up in size of intake tube make a difference? That would indicate the throttle body wasn't a restriction and the intake was(which I'm the deep reality of it... It wasn't) funny how people can make 550+rwhp with a 'too small' 90mm and 4 inch intake. Weird.
Hahahaha hahahahahaha that's ludicrous. You SERIOUSLY have no idea what you're talking about literally whatsoever. That's so far off base that it's on its own planet.
A 200hp engine will NOT EVER make more power with a 850 than it does with a 650.
It will literally only consume what it can consume...abd at 650cfm it has more than plenty to consume. You clearly don't understand how a carb works either 😂😂😂😂😂 it needs a vacuum source(if you go too big it creates to poor vacuum signal since the air is going to travel slower through the venteri)
A 6.0 needing a 92mm throttle body hahahahaha dear lord. No. Just no.
There is no gain on a 6.0 going from a 3.5 to 4.0 tube intake. Literally none. Why? Because it doesn't need it. Porting a throttle body is minimal and nearly a wasted effort which just shows your lack of knowledge on this subject. Have you measured pressure differences? Calculated the air density? I mean the mental gymnastics you're doing is purely amazing. Explain to me.... If the throttle body is the problem how did going up in size of intake tube make a difference? That would indicate the throttle body wasn't a restriction and the intake was(which I'm the deep reality of it... It wasn't) funny how people can make 550+rwhp with a 'too small' 90mm and 4 inch intake. Weird.
I guess you should actually try testing some of this sometime rather than being a keyboard warrior.
Porting a throttle body is not always minimal and I have seen added hp from doing it. Many GM throttle bodies are tapered and have a shrouded area where the bore is smaller than the manifold opening, GM does this on production vehicles to tame the off-idle feel.
A larger intake tube than the throttle body absolutely DOES add power as it provides less resistance to flow. The throttle body actually becomes a venturi and additional air is rammed through the throttle body. Take a drinking straw, blow through it. Now cut the straw down to 1" length and blow through it again. It will be much easier to blow through the same diameter tube that is only 1" long. Simple physics that I am laughing that you cannot seem to grasp or understand and are attempting to lecture me over. The less resistance to flow the less energy the pistons have to exert to pump in the airflow and the higher the VE.
I guess my 5.6L Titan did not pickup 2 tenths of a second and 3 mph in the 1/8 mile swapping the stock 3.25 ID" air intake for a 4" Airaid MXP intake in back-to-back runs at the track either. Then the truck slowed back down the same amount when I put the stock air intake back on.
I have measured MAP, recorded mass air flow values, calculated VE even for changes. Not hard to do with a scanner like HP Tuners tied directly to the vehicle PCM.
I absolutely do understand how a carburetor works. I am very knowledgeable on function as well as tuning them, but it is overly apparent you are not. I have also tested 3 different sized carburetors on a basic old 180 net hp rated LM1 350 in a 1980 Z/28 making about 200 hp at the crank. 650 cfm, 750 cfm and 850 cfm. Each increase in carburetor CFM provided an increase in peak hp as well as power above peak. Each increase in CFM provided lower intake manifold vacuum. The 750 made the highest average torque and had marginally better manners than the 850. I ran the test at the time because all 3 carbs needed to be test run anyway, so why not compare.
Actually, PowerNation did the same test on a smaller LG4 305 and even put a 1050 Dominator on it. They made increasing power with larger carburetors. It was not until they put a 1050 Dominator on the little 305 that the vacuum became so low that it was hard to meter fuel at WOT and low rpm. They also tested air filters and like the tests I have done increasing air intake tubing sizes, the less restrictive the filter, the more power it made. If you call 10+ hp a waste of time using a 92mm TB and a 4" air intake on a 6.0L, so be it. These kind of parts are cheap and fun to experiment with.
A 502 Ramjet makes 502 HP through a L98 TPI throttle body. But it loses 30 HP doing it. People may have made 550 HP with a 4" intake, but at what cost to power? I think the difference between a 4" and 5" air intake would shock you even at 450 hp.
I guess you should actually try testing some of this sometime rather than being a keyboard warrior.
Porting a throttle body is not always minimal and I have seen added hp from doing it. Many GM throttle bodies are tapered and have a shrouded area where the bore is smaller than the manifold opening, GM does this on production vehicles to tame the off-idle feel.
A larger intake tube than the throttle body absolutely DOES add power as it provides less resistance to flow. The throttle body actually becomes a venturi and additional air is rammed through the throttle body. Take a drinking straw, blow through it. Now cut the straw down to 1" length and blow through it again. It will be much easier to blow through the same diameter tube that is only 1" long. Simple physics that I am laughing that you cannot seem to grasp or understand and are attempting to lecture me over. The less resistance to flow the less energy the pistons have to exert to pump in the airflow and the higher the VE.
I guess my 5.6L Titan did not pickup 2 tenths of a second and 3 mph in the 1/8 mile swapping the stock 3.25 ID" air intake for a 4" Airaid MXP intake in back-to-back runs at the track either. Then the truck slowed back down the same amount when I put the stock air intake back on.
I have measured MAP, recorded mass air flow values, calculated VE even for changes. Not hard to do with a scanner like HP Tuners tied directly to the vehicle PCM.
I absolutely do understand how a carburetor works. I am very knowledgeable on function as well as tuning them, but it is overly apparent you are not. I have also tested 3 different sized carburetors on a basic old 180 net hp rated LM1 350 in a 1980 Z/28 making about 200 hp at the crank. 650 cfm, 750 cfm and 850 cfm. Each increase in carburetor CFM provided an increase in peak hp as well as power above peak. Each increase in CFM provided lower intake manifold vacuum. The 750 made the highest average torque and had marginally better manners than the 850. I ran the test at the time because all 3 carbs needed to be test run anyway, so why not compare.
Actually, PowerNation did the same test on a smaller LG4 305 and even put a 1050 Dominator on it. They made increasing power with larger carburetors. It was not until they put a 1050 Dominator on the little 305 that the vacuum became so low that it was hard to meter fuel at WOT and low rpm. They also tested air filters and like the tests I have done increasing air intake tubing sizes, the less restrictive the filter, the more power it made. If you call 10+ hp a waste of time using a 92mm TB and a 4" air intake on a 6.0L, so be it. These kind of parts are cheap and fun to experiment with.
A 502 Ramjet makes 502 HP through a L98 TPI throttle body. But it loses 30 HP doing it. People may have made 550 HP with a 4" intake, but at what cost to power? I think the difference between a 4" and 5" air intake would shock you even at 450 hp.
I have tested all of your theories and they are 100 percent incorrect. Your resistance to flow ONLY MATTERS of there is a restriction in which case there isn't... Just lol at the OPs set up... It didn't make any more power than what it did before(variation in weather could have made the SMALL difference or even the intake). Considering what he did... In a cammed 6.0 it already shows your idea that on bigger is better hur hur is thrown out the window. Here's your test completely proving you wrong.... again.
Hahaha your 502 theory is already wrong... It makes the exact same power as a carb does 😂
Funny how a 489 I played with made... Exactly the same power with a 90mm(4 inch intake) than it did with a 102mm(5 inch)
This was in the mid 600s... WEIRD.
Last edited by 02redchevy; 08-31-2023 at 07:10 AM.
Once an engine is getting enough air with no intake manifold vacuum (aka atmospheric pressured), a larger TB or carb won't make any more power, as 02redchevy has shown above.
Basically, it peaks before WOT happens, giving you no throttler response beyond that point. Once it gets enough air, nothing more happens.
Once an engine is getting enough air with no intake manifold vacuum (aka atmospheric pressured), a larger TB or carb won't make any more power, as 02redchevy has shown above.
Basically, it peaks before WOT happens, giving you no throttler response beyond that point. Once it gets enough air, nothing more happens.
As I said though before. It has to get enough air. I know how to gather the data on that.
I have tested all of your theories and they are 100 percent incorrect. Your resistance to flow ONLY MATTERS of there is a restriction in which case there isn't... Just lol at the OPs set up... It didn't make any more power than what it did before(variation in weather could have made the SMALL difference or even the intake). Considering what he did... In a cammed 6.0 it already shows your idea that on bigger is better hur hur is thrown out the window. Here's your test completely proving you wrong.... again.
Hahaha your 502 theory is already wrong... It makes the exact same power as a carb does 😂
Funny how a 489 I played with made... Exactly the same power with a 90mm(4 inch intake) than it did with a 102mm(5 inch)
This was in the mid 600s... WEIRD.
Still an increase from a decrease in intake manifold vacuum. Never claimed it was a huge increase. 2 hp on a 200 hp engine is 1% and 1% on a 600 hp engine is 6 hp. You can claim it as weather change, but every dyno I have ever been around has a weather station and uses that to correct for those changes automatically.
AIRFLOW= ((engine c.i)*(max RPM))/3456. Multiply that times VE ratio. A 347 consumes ~600cfms at 6000 rpms. If your TB supports 600cfms....guess what? You don't need a bigger TB.
Still an increase from a decrease in intake manifold vacuum. Never claimed it was a huge increase. 2 hp on a 200 hp engine is 1% and 1% on a 600 hp engine is 6 hp. You can claim it as weather change, but every dyno I have ever been around has a weather station and uses that to correct for those changes automatically.
You can just assume it'll be 1 percent.... That's 100 percent not the case. The oil could have been 10 degrees warmer and you'd see 1 or 1hp.... We now know you're the person to put a 4500 carb on a 350 and swear you'd outrun anyone in the neighborhood.
AIRFLOW= ((engine c.i)*(max RPM))/3456. Multiply that times VE ratio. A 347 consumes ~600cfms at 6000 rpms. If your TB supports 600cfms....guess what? You don't need a bigger TB.
And that's at 100 percent VE
Which most engines don't manage to get to.
My 5.3 sbe truck made 396 on the tire all motor.
243 heads port, polish and milled .030
Btr stage 3 truck cam 218/224 553/553 110+0
102 mm intake and throttle body
660 Dual springs and trunion upgrade
This is a 2000 model truck with lm7
My 5.3 sbe truck made 396 on the tire all motor.
243 heads port, polish and milled .030
Btr stage 3 truck cam 218/224 553/553 110+0
102 mm intake and throttle body
660 Dual springs and trunion upgrade
This is a 2000 model truck with lm7
That port/polish is what made that engine shine.
Intake and throttle body didn't do a damn thing.
That port/polish is what made that engine shine.
Intake and throttle body didn't do a damn thing.
yeh it definitely made a difference, that's one of the more recent mods ive done it, well besides the turbo but when it was all motor it definitely made a difference. It also gave me a little more rpm up top. You went over my head with all the ve stuff. I'm not to familiar with that. The truck had the intake on it when I bought it so that's what I went with
yeh it definitely made a difference, that's one of the more recent mods ive done it, well besides the turbo but when it was all motor it definitely made a difference. It also gave me a little more rpm up top. You went over my head with all the ve stuff. I'm not to familiar with that. The truck had the intake on it when I bought it so that's what I went with
I mean it will work, but it won't make any more power than an LS6 intake or something similar.
Still an increase from a decrease in intake manifold vacuum. Never claimed it was a huge increase. 2 hp on a 200 hp engine is 1% and 1% on a 600 hp engine is 6 hp. You can claim it as weather change, but every dyno I have ever been around has a weather station and uses that to correct for those changes automatically.
You can just assume it'll be 1 percent.... That's 100 percent not the case. The oil could have been 10 degrees warmer and you'd see 1 or 1hp.... We now know you're the person to put a 4500 carb on a 350 and swear you'd outrun anyone in the neighborhood.
Actually I am the guy that runs Quadrajets, up to 850 cfm on demand.
Hahahaha that just proves all of our points even more 😂
Your air valve only allows for as much air as the engine needs versus the actual total cfm of the carb(if memory serves me up to 780 but it's been a while)
Hahahaha that just proves all of our points even more 😂
Your air valve only allows for as much air as the engine needs versus the actual total cfm of the carb(if memory serves me up to 780 but it's been a while)
While that is true it has the capacity to move 850 cfm. That is capable of providing maximum power at all times.
I have used progressive linkage 4bbl 4150 flange throttle bodys flowing 1,000 cfm on port fuel injected engines making 400-450 HP. Does not hurt a thing to have more CFM than required. With a good air filter that setup is at atmospheric pressure when the throttle plates are wide open. If you are paying the same $ for a throttle body and intake tubing on a port fuel injected engine go for the biggest practical unit.
According to the math and you an 80mm throttle body and 4" air duct should provide zero loss on a 383 spinning 5,500 rpm and that is not what I have observed. With a K&N filter in a GM air box with a 4" tube, 100mm MAF and 80mm TB, the 383 builds 10 KPA of vacuum at 5,500. At 4,500 rpm that setup is already starting to pull a noticeable intake vacuum. Removing the filter changed nothing, running an open TB reduced the loss in half. A bigger 90mm throttle body would eliminate the loss entirely. I happen to have a Fitech 92mm to put on this engine a long with a larger K&N and heatshield to remove the factory air box. Key On Engine Off the MAP was reading 99 KPA, at 4,500 rpm it already had 6KPA of vacuum and it only gets worse as it revs out. It will drop clear down to 89 KPA at 5,500.
08-30-2023, 11:33 PM
