fuel delivery differences (HP) |
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fuel delivery differences (HP) |
RonnieJ |
Feb 2 2014, 11:30 AM
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#1
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RonnieJ Group: Members Posts: 230 Joined: 16-June 03 From: Sterling Heights, Michigan Member No.: 829 Region Association: Upper MidWest |
What will a stock 1.7 produce in H.P.with the following.
Progressive 32/36 Weber 40's D-Jet F.I. |
brant |
Feb 2 2014, 11:41 AM
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#2
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914 Wizard Group: Members Posts: 11,640 Joined: 30-December 02 From: Colorado Member No.: 47 Region Association: Rocky Mountains |
not answering your question exactly
but its more about throttle response than actual HP numbers for example a giant set of 48IDA carbs might actually flow the most air and on a dyno at 7K might show the most hp... but they won't be driveable below 6K the progressive carb also isn't very smooth when the fuel falls out of suspension in the intake runners causing rich and lean moments.. so its more than just HP unless you are racing and have a very narrow range of 1000rpm or less that you are trying to get it to function within. you can make your question more specific what are you trying to do? are you asking which induction to use on a stock 1.7 with stock everything else including heads, compression, cams, and exhaust? then DJet is the answer brant |
McMark |
Feb 2 2014, 12:33 PM
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#3
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914 Freak! Group: Retired Admin Posts: 20,179 Joined: 13-March 03 From: Grand Rapids, MI Member No.: 419 Region Association: None |
Assuming they could all be tuned perfectly, about the same.
HP is made in displacement, heads (valves, chamber shape and size, etc), compression ratio, camshaft. HP is unlocked when there is a restriction in the intake/exhaust that gets removed. But if the intake is capable of more than the peak engine HP (1.7 with 40IDFs) then it won't make more power. Your intake is larger than your engine. The only way to really make a 1.7 produce more HP is forced induction. |
ConeDodger |
Feb 2 2014, 01:02 PM
Post
#4
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Apex killer! Group: Members Posts: 23,614 Joined: 31-December 04 From: Tahoe Area Member No.: 3,380 Region Association: Northern California |
Assuming they could all be tuned perfectly, about the same. HP is made in displacement, heads (valves, chamber shape and size, etc), compression ratio, camshaft. HP is unlocked when there is a restriction in the intake/exhaust that gets removed. But if the intake is capable of more than the peak engine HP (1.7 with 40IDFs) then it won't make more power. Your intake is larger than your engine. The only way to really make a 1.7 produce more HP is forced induction. Ask him how he knows... (IMG:style_emoticons/default/evilgrin.gif) |
RonnieJ |
Feb 2 2014, 01:06 PM
Post
#5
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RonnieJ Group: Members Posts: 230 Joined: 16-June 03 From: Sterling Heights, Michigan Member No.: 829 Region Association: Upper MidWest |
not answering your question exactly but its more about throttle response than actual HP numbers for example a giant set of 48IDA carbs might actually flow the most air and on a dyno at 7K might show the most hp... but they won't be driveable below 6K the progressive carb also isn't very smooth when the fuel falls out of suspension in the intake runners causing rich and lean moments.. so its more than just HP unless you are racing and have a very narrow range of 1000rpm or less that you are trying to get it to function within. you can make your question more specific what are you trying to do? are you asking which induction to use on a stock 1.7 with stock everything else including heads, compression, cams, and exhaust? then DJet is the answer brant Thanks Brant, I understand that better flowing heads and differnet cam and larger displacement make more HP but I always heard that fuel delivery can also give you more horsepower. I am not trying to change anything on my current engine and was just wondering if fuel systems can actually incease horsepower on a stock engine. |
McMark |
Feb 2 2014, 01:30 PM
Post
#6
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914 Freak! Group: Retired Admin Posts: 20,179 Joined: 13-March 03 From: Grand Rapids, MI Member No.: 419 Region Association: None |
Gasoline combustion is based on a critical mixture of oxygen and fuel. Too far in either direction (rich/lean) will drop off power. If you do the math, it's 14.7 parts air to 1 part fuel. But since engines aren't math problems, often WOT power pulls perform better around 12:1 or more. But in those cases it's technically incorrect to say that more fuel is making more power. More fuel is overcoming the inadequacy/irregularity of the intake and fuel delivery systems.
The real answer is one of those frustratingly vague responses. Peak horsepower is created with just enough fuel. No more. No less. A progressive single carb gives you one fuel adjustment for the whole motor. So it's wrong most of the time. Kind of like this... A dual carb setup give you one fuel adjustment per cylinder. So it's a little more right, more of the time. Kind of like this... A D-Jet fuel setup is even more right, even more of the time. Kind of like this... A modern, dyne tuned, digital fuel injection system with lots of fuel map resolution is going to be even more right. Kind of like this... |
brant |
Feb 2 2014, 01:55 PM
Post
#7
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914 Wizard Group: Members Posts: 11,640 Joined: 30-December 02 From: Colorado Member No.: 47 Region Association: Rocky Mountains |
not answering your question exactly but its more about throttle response than actual HP numbers for example a giant set of 48IDA carbs might actually flow the most air and on a dyno at 7K might show the most hp... but they won't be driveable below 6K the progressive carb also isn't very smooth when the fuel falls out of suspension in the intake runners causing rich and lean moments.. so its more than just HP unless you are racing and have a very narrow range of 1000rpm or less that you are trying to get it to function within. you can make your question more specific what are you trying to do? are you asking which induction to use on a stock 1.7 with stock everything else including heads, compression, cams, and exhaust? then DJet is the answer brant Thanks Brant, I understand that better flowing heads and differnet cam and larger displacement make more HP but I always heard that fuel delivery can also give you more horsepower. I am not trying to change anything on my current engine and was just wondering if fuel systems can actually incease horsepower on a stock engine. Ronnie, I would guess... that a set of duel 34's, or duel 40 carbs would slightly improve the horsepower on a stock motor. it would also change the intake sound/noise and be louder and "sound" faster it might improve throttle response if the jetting was dialed in but the trade-off would be: harder to start and a loss of MPG if dialed in for midrange, the bottom end would not be better than DJet if dialed in for low rpm, the top end will not improve over DJet brant |
Mike Bellis |
Feb 2 2014, 02:10 PM
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#8
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Resident Electrician Group: Members Posts: 8,345 Joined: 22-June 09 From: Midlothian TX Member No.: 10,496 Region Association: None |
Gasoline combustion is based on a critical mixture of oxygen and fuel. Too far in either direction (rich/lean) will drop off power. If you do the math, it's 14.7 parts air to 1 part fuel. But since engines aren't math problems, often WOT power pulls perform better around 12:1 or more. But in those cases it's technically incorrect to say that more fuel is making more power. More fuel is overcoming the inadequacy/irregularity of the intake and fuel delivery systems. The real answer is one of those frustratingly vague responses. Peak horsepower is created with just enough fuel. No more. No less. A progressive single carb gives you one fuel adjustment for the whole motor. So it's wrong most of the time. Kind of like this... A dual carb setup give you one fuel adjustment per cylinder. So it's a little more right, more of the time. Kind of like this... A D-Jet fuel setup is even more right, even more of the time. Kind of like this... A modern, dyne tuned, digital fuel injection system with lots of fuel map resolution is going to be even more right. Kind of like this... Great analogy! (IMG:style_emoticons/default/smilie_pokal.gif) |
Chris Pincetich |
Feb 2 2014, 02:19 PM
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#9
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B-) Group: Members Posts: 2,082 Joined: 3-October 05 From: Point Reyes Station, CA Member No.: 4,907 Region Association: Northern California |
What will a stock 1.7 produce in H.P.with the following. Progressive 32/36 Weber 40's D-Jet F.I. (IMG:style_emoticons/default/biggrin.gif) Now ask about HP differences with various exhaust options (IMG:style_emoticons/default/beerchug.gif) Or, use "search" and read up on the tons of great info stored at 914world I want a turbo! (IMG:style_emoticons/default/aktion035.gif) (IMG:style_emoticons/default/smoke.gif) |
RonnieJ |
Feb 2 2014, 02:20 PM
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#10
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RonnieJ Group: Members Posts: 230 Joined: 16-June 03 From: Sterling Heights, Michigan Member No.: 829 Region Association: Upper MidWest |
Thanks all for the lesson. Never can learn to much when it comes to these engines.
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bzettner |
Feb 2 2014, 03:40 PM
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#11
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Member Group: Members Posts: 211 Joined: 2-June 13 From: San Antonio, TX Member No.: 15,951 Region Association: Southwest Region |
What will a stock 1.7 produce in H.P.with the following. Progressive 32/36 Weber 40's D-Jet F.I. Your FI 1.7 produced 79 Hp, new. I think mine is pumping out 78 (IMG:style_emoticons/default/poke.gif) |
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