Bigger TB: Is it time?
04-02-2003, 09:25 PM
#5
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Join Date: Sep 2001
Location: Gordonsville,New Brunswick,Canada
Posts: 208
Well i noticed no difference when i put mine on but i have head work and the stock cam and besides if you gain 10hp on a car that already has over 300 and weighs over 3000 lbs you probably wouldn't notice anyway.I say go for it but get a bored stock one or a used one and it will be worth it.I got mine for $100 plus mine on trade in and the best thing about doing this is it is a easy job.
04-02-2003, 09:42 PM
#6
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Join Date: Mar 2003
Location: The Great State of Texas.
Posts: 465
If you are stock, yes, if you are cammed, HELL yes.
People, peak horsepower means ****, except to dyno queens.
All LT1's will benefit from more air. Not just cammed ones. Instead of falling flat on its face at 5K, it comes alive....Make use of those new valve springs you (hopefully) installed, and actually MAKE some TQ and HP above 5000, instead of seeing a tumble.
200 well spent, IMHO.
Even the S2000 makes 240HP...Only beacuse HP is a product of Torque times RPM...driving in city traffic in one of those is like a convertible civic, all show, no go.
People, peak horsepower means ****, except to dyno queens.
All LT1's will benefit from more air. Not just cammed ones. Instead of falling flat on its face at 5K, it comes alive....Make use of those new valve springs you (hopefully) installed, and actually MAKE some TQ and HP above 5000, instead of seeing a tumble.
200 well spent, IMHO.
Even the S2000 makes 240HP...Only beacuse HP is a product of Torque times RPM...driving in city traffic in one of those is like a convertible civic, all show, no go.
04-02-2003, 10:23 PM
#9
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Join Date: Mar 2003
Location: The Great State of Texas.
Posts: 465
I'd like to know how adding more air is a problem to these people...LOL
As I said, peak HP may go up, it may fall(due to power curve flattening out, but probobly not on a cammed car). Peak HP is for guys who never drive their cars. I am interested in a big, flat tourque curve.
I can bet you dollars to pesos you will have a more useable torque curve at 5000+rpms.
Also, invest in PCM programming, it'll add HP that your stock programming WILL take away.
As I said, peak HP may go up, it may fall(due to power curve flattening out, but probobly not on a cammed car). Peak HP is for guys who never drive their cars. I am interested in a big, flat tourque curve.
I can bet you dollars to pesos you will have a more useable torque curve at 5000+rpms.
Also, invest in PCM programming, it'll add HP that your stock programming WILL take away.
04-02-2003, 10:30 PM
#10
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Join Date: Nov 2001
Location: Kansas
Posts: 3,517
Originally posted by HM Murdock
I'd like to know how adding more air is a problem to these people...LOL
As I said, peak HP may go up, it may fall(due to power curve flattening out, but probobly not on a cammed car). Peak HP is for guys who never drive their cars. I am interested in a big, flat tourque curve.
I can bet you dollars to pesos you will have a more useable torque curve at 5000+rpms.
Also, invest in PCM programming, it'll add HP that your stock programming WILL take away.
I'd like to know how adding more air is a problem to these people...LOL
As I said, peak HP may go up, it may fall(due to power curve flattening out, but probobly not on a cammed car). Peak HP is for guys who never drive their cars. I am interested in a big, flat tourque curve.
I can bet you dollars to pesos you will have a more useable torque curve at 5000+rpms.
Also, invest in PCM programming, it'll add HP that your stock programming WILL take away.
you dont use torque at 5000 rpms... you use horsepower
why would the stock program take away hp?
a 52mm or 58mm tb will act exactly like a 48mm tb until you are above probably 80% throttle. before that point the flow is going to be exactly the same. the extra size is only taken into account once you have open it up enough to outflow the max flow of the stocker which is likely only above 4k rpm even with a hotcam.
04-02-2003, 11:03 PM
#11
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Join Date: Jul 2000
Location: Buffalo, NY
Posts: 2,735
If more air is always better than I guess the all the stock guys should go ahead and throw a monoblade on their car...theyll probably gain...like 25 HP since itll flow 1200+ cfm.
Unless you are seriously choking your car at high RPM's it wouldnt be worth the money IMO.
My board friend rskrause was using a 48mm TB on his old set up when his car made 700+rwhp. He is an example of someone who could have gained some power but he must have decided that the gain wasnt worth the cash....
Unless you are seriously choking your car at high RPM's it wouldnt be worth the money IMO.
My board friend rskrause was using a 48mm TB on his old set up when his car made 700+rwhp. He is an example of someone who could have gained some power but he must have decided that the gain wasnt worth the cash....
04-02-2003, 11:20 PM
#13
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Location: The Great State of Texas.
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Originally posted by turbo_Z
you dont use torque at 5000 rpms... you use horsepower
you dont use torque at 5000 rpms... you use horsepower
Do you still think you don't use torque up high?
why would the stock program take away hp?
He is not internally stock, so the stock program is no longer valid. Duh.
a 52mm or 58mm tb will act exactly like a 48mm tb until you are above probably 80% throttle. before that point the flow is going to be exactly the same. the extra size is only taken into account once you have open it up enough to outflow the max flow of the stocker which is likely only above 4k rpm even with a hotcam.
Didn't I say the difference would be above 5K?
Geeze
Ignorance of physics is no excuse for lost Torque.
Last edited by HM Murdock; 04-02-2003 at 11:22 PM.
04-02-2003, 11:28 PM
#14
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Join Date: Nov 2001
Location: Kansas
Posts: 3,517
Originally posted by HM Murdock
Bull****. All Horsepower is torque in ft./lbs. times rpm, divided by 5,252.
Do you still think you don't use torque up high?
He is not internally stock, so the stock program is no longer valid. Duh.
Gee, more power at WOT, who wants that?
Didn't I say the difference would be above 5K?
Geeze
Ignorance of physics is no excuse for lost Torque.
Bull****. All Horsepower is torque in ft./lbs. times rpm, divided by 5,252.
Do you still think you don't use torque up high?
He is not internally stock, so the stock program is no longer valid. Duh.
Gee, more power at WOT, who wants that?
Didn't I say the difference would be above 5K?
Geeze
Ignorance of physics is no excuse for lost Torque.
you said the torque curve would be more usable at 5k rpm which it not accurate.. maybe hp curve but everyone knows you dont have torque up high. have you ever seen a dyno graph?
ok i misunderstood you about the programming. i thought you were saying the tb would rob him of hp because of this stock tune.
04-02-2003, 11:39 PM
#15
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Join Date: Jul 2000
Location: Buffalo, NY
Posts: 2,735
This was posted a WHILE back by injuneer when I had asked why Craig at GTP said a 58mm TB was costing me power on my head cam A4 car....take it for whats its worth.
"I can tell you why an oversize TB won't help. Just because a TB can flow more air at a given pressure drop doesn't mean it will cause more air to flow into your specific engine. Air flow is determined largely by the heads and cam. The TB is simply there to act as a "valve".... allowing the engine to run at less than 100%.
Yes, if you had a severely undersized TB to start with, you would choke off the amount of air that can flow into the engine, but put a grossly oversize TB in place of a correctly sized TB, and it isn't going to magically make the engine demand/flow more air.
A measurement of flow means nothing if it isn't accompanied by a pressure drop. Pressure drop is roughly proportional to the diameter raised to the 2.5 power. Once you reach a certain point, the reduction in pressure drop is negligible. And the only thing that is going to change the amount of air filling the pistons is the pressure drop in the air inlet track. A fraction of an inch of water isn't going to alter volumetric efficiency any appreciable amount.
As a point of reference, when we first set up my engine, we used N-alpha programming, where fuel is essentially determined by throttle position and rpm. At 77% open, the 58mm TB was flowing about as much air as the engine needed. In effect, the engine could have made the same amount of power on a 52mm TB. Going larger did not cause the engine to flow more air, or make more power.
I can't tell you why Craig is saying the 58mm is costing you power because you have an A4. I doubt that the velocity of the air through the TB bores is of major significance, since the volume of the plenum relative to the volume of the runners should effectively decouple the TB from the runners. I "think" that's the case... can't prove it for the specifics of the LT1 plenum.
But the idea that putting a larger TB or a larger MAF sensor or a larger CAI magically makes your engine flow significantly more air is a popular misconception. The increase in flow is proportional to the reduction in pressure loss, relative to full atmospheric pressure.... a few 1/10th's of an inch H2O from an oversize component means virtually nothing."
"I can tell you why an oversize TB won't help. Just because a TB can flow more air at a given pressure drop doesn't mean it will cause more air to flow into your specific engine. Air flow is determined largely by the heads and cam. The TB is simply there to act as a "valve".... allowing the engine to run at less than 100%.
Yes, if you had a severely undersized TB to start with, you would choke off the amount of air that can flow into the engine, but put a grossly oversize TB in place of a correctly sized TB, and it isn't going to magically make the engine demand/flow more air.
A measurement of flow means nothing if it isn't accompanied by a pressure drop. Pressure drop is roughly proportional to the diameter raised to the 2.5 power. Once you reach a certain point, the reduction in pressure drop is negligible. And the only thing that is going to change the amount of air filling the pistons is the pressure drop in the air inlet track. A fraction of an inch of water isn't going to alter volumetric efficiency any appreciable amount.
As a point of reference, when we first set up my engine, we used N-alpha programming, where fuel is essentially determined by throttle position and rpm. At 77% open, the 58mm TB was flowing about as much air as the engine needed. In effect, the engine could have made the same amount of power on a 52mm TB. Going larger did not cause the engine to flow more air, or make more power.
I can't tell you why Craig is saying the 58mm is costing you power because you have an A4. I doubt that the velocity of the air through the TB bores is of major significance, since the volume of the plenum relative to the volume of the runners should effectively decouple the TB from the runners. I "think" that's the case... can't prove it for the specifics of the LT1 plenum.
But the idea that putting a larger TB or a larger MAF sensor or a larger CAI magically makes your engine flow significantly more air is a popular misconception. The increase in flow is proportional to the reduction in pressure loss, relative to full atmospheric pressure.... a few 1/10th's of an inch H2O from an oversize component means virtually nothing."