thnx!!!!!1
05-17-2001, 04:02 AM
#11
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Believe what you want, but Random knows me personally, and I'm telling you the 4-1 design is what you want if you race.
"Low end torque" as you describe it means more power at lower RPM's. I don't know what you're thinking, but when you're racing from stoplight to stoplight or in the quarter mile, your car DOES NOT STAY AT LOW RPM's.
When you are stoplight racing, you might be at "low" RPM's for all of about 1/2 of a second. Everything else during that race is high RPM's. Everything. No excuses.
Unless you shift at 4K, "low end torque" isn't going to help you in a streetlight or quarter mile race. Period. End of discussion. You shift right at the revlimiter, and in the next gear you're already above 4500 RPM's. Where is "Low End Torque" going to help you if you're always above 4500 RPM's while you're racing?
If you would have read my first response, I said that low end torque is determined foremost by the tuning of the primaries. Tuning in this instance means primary diameter and lenth before the collector, and HVE's 4-1 design has it down really well. I don't know about SR's design, because I don't have one.
But simply saying "4-1 designs always lose low-end but give you better top end, and 4-2-1 designs always give you low-end but dont' really help on the top end" is a misleading statement.
It 100% depends on the tuning of the header, and you can say with ZERO ACCURACY that just because of a design choice which header will work better for which situation.
If you want to give people opinions on which header gives you which results, you need a dynograph before (stock) and after (w/header) on each design. There are considerable amounts of physics involved with header design that you simply cannot sum up with "these usually work this way"
"Low end torque" as you describe it means more power at lower RPM's. I don't know what you're thinking, but when you're racing from stoplight to stoplight or in the quarter mile, your car DOES NOT STAY AT LOW RPM's.
When you are stoplight racing, you might be at "low" RPM's for all of about 1/2 of a second. Everything else during that race is high RPM's. Everything. No excuses.
Unless you shift at 4K, "low end torque" isn't going to help you in a streetlight or quarter mile race. Period. End of discussion. You shift right at the revlimiter, and in the next gear you're already above 4500 RPM's. Where is "Low End Torque" going to help you if you're always above 4500 RPM's while you're racing?
If you would have read my first response, I said that low end torque is determined foremost by the tuning of the primaries. Tuning in this instance means primary diameter and lenth before the collector, and HVE's 4-1 design has it down really well. I don't know about SR's design, because I don't have one.
But simply saying "4-1 designs always lose low-end but give you better top end, and 4-2-1 designs always give you low-end but dont' really help on the top end" is a misleading statement.
It 100% depends on the tuning of the header, and you can say with ZERO ACCURACY that just because of a design choice which header will work better for which situation.
If you want to give people opinions on which header gives you which results, you need a dynograph before (stock) and after (w/header) on each design. There are considerable amounts of physics involved with header design that you simply cannot sum up with "these usually work this way"
05-17-2001, 04:28 AM
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You see though, the problem is that it's not entirely opinion...
I am 100% correct that everyone who "stoplight races" and runs quarter miles has their car at high RPM's. There is nobody on this forum that is racing the guy next to them and then shifts halfway up the tachometer. When was the last time you were racing the guy next to you, and decided you would shift at 4000 RPM's? Do you really do that? Or do you wait until about 6500 or even higher before you shift?
If you have any head on your shoulders, then you shift when the tachometer is swinging past 6500 RPM's.
When you shift from 1st gear at 6775 RPM's (right at the rev-limiter for the 1997 Tiburon anyway), you land in 2nd gear at 4895 RPM's. That's four-thousand eight hundred and ninety five RPM's. Where does 4900 RPM's seem to anyone like "low end"?
And what good would "low end" do for me if I'm always right at 5K when I shift? If I'm racing the guy next to me in his souped up Civic, I'm not taking any advantage of ANY "low end torque".
The only point where low-end torque really matters is either A: cars with VERY tall gears, or B: if you're a beginner roadcourse driver that likes to kinda "stick" in one gear and drag the car up and down the tachometer.
Everying I have just stated above is 100% pure fact and can be backed by anyone who races almost any four banger on this planet.
However, it is my opinion that the 4-1 design from HVE does not suffer anything like you outlined, as determined by my dyno sheets. If 4-1 headers truly lost torque at low RPM's, then I must just have a magical motor that generates such wonderful torque at the tires to combat my hideous 4-1 design header.
That last paragraph was my opinion, and is subject to debate.
I'm sorry if I offend or some off like an ass, but I have a severe distaste for misinformation. If I stumble upon a forum or a person who is misinformed, I will do my best to correct the situation. This is such a case, and I don't want someone reading this forum to take misinformation as 100% fact and never really know the truth.
Everyone is allowed to question what I post, but I only post what I have 100% factual backing on, and this is such a case. The fluid dynamics involved in header design are often so complex that every single company usually builds at least a handful of prototypes. The only real way you can say that "This header does THIS" is by actually strapping the header to a car and testing it.
There are lots of "general rules" in automotive performance, but all of them have fine print and do not always show the real world results.
-Red-
FXTreme Performance Forums Moderator
I am 100% correct that everyone who "stoplight races" and runs quarter miles has their car at high RPM's. There is nobody on this forum that is racing the guy next to them and then shifts halfway up the tachometer. When was the last time you were racing the guy next to you, and decided you would shift at 4000 RPM's? Do you really do that? Or do you wait until about 6500 or even higher before you shift?
If you have any head on your shoulders, then you shift when the tachometer is swinging past 6500 RPM's.
When you shift from 1st gear at 6775 RPM's (right at the rev-limiter for the 1997 Tiburon anyway), you land in 2nd gear at 4895 RPM's. That's four-thousand eight hundred and ninety five RPM's. Where does 4900 RPM's seem to anyone like "low end"?
And what good would "low end" do for me if I'm always right at 5K when I shift? If I'm racing the guy next to me in his souped up Civic, I'm not taking any advantage of ANY "low end torque".
The only point where low-end torque really matters is either A: cars with VERY tall gears, or B: if you're a beginner roadcourse driver that likes to kinda "stick" in one gear and drag the car up and down the tachometer.
Everying I have just stated above is 100% pure fact and can be backed by anyone who races almost any four banger on this planet.
However, it is my opinion that the 4-1 design from HVE does not suffer anything like you outlined, as determined by my dyno sheets. If 4-1 headers truly lost torque at low RPM's, then I must just have a magical motor that generates such wonderful torque at the tires to combat my hideous 4-1 design header.
That last paragraph was my opinion, and is subject to debate.
I'm sorry if I offend or some off like an ass, but I have a severe distaste for misinformation. If I stumble upon a forum or a person who is misinformed, I will do my best to correct the situation. This is such a case, and I don't want someone reading this forum to take misinformation as 100% fact and never really know the truth.
Everyone is allowed to question what I post, but I only post what I have 100% factual backing on, and this is such a case. The fluid dynamics involved in header design are often so complex that every single company usually builds at least a handful of prototypes. The only real way you can say that "This header does THIS" is by actually strapping the header to a car and testing it.
There are lots of "general rules" in automotive performance, but all of them have fine print and do not always show the real world results.
-Red-
FXTreme Performance Forums Moderator
05-17-2001, 10:34 AM
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Mario-
I respect your opinion, but....
The tibby has between 90 and 100 Ft Lbs at 2000 rpm. Even in the automatic. The low end does just fine.... It's the high end that needs the shoring up. Look at the stock dyno runs...
Speed State's Stock Dyno run. 5 Speed Manual
Bat Lord's Dyno run. Automatic.
I respect your opinion, but....
The tibby has between 90 and 100 Ft Lbs at 2000 rpm. Even in the automatic. The low end does just fine.... It's the high end that needs the shoring up. Look at the stock dyno runs...
Speed State's Stock Dyno run. 5 Speed Manual
Bat Lord's Dyno run. Automatic.
05-17-2001, 11:29 AM
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The first chart is a 5 speed? Why would say is the lack of torque at high end? Is it exhaust problems or is the highly restricted intake tibby has?
I also see a valley between 3000 and 4000 that could be improved!
Nice charts.
I also see a valley between 3000 and 4000 that could be improved!
Nice charts.
05-17-2001, 02:31 PM
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Where Torque and HP cross there is a dip in the dyno yes. As our engines "wind" up, the get less efficent. Remember HP is torque over time. If you increase torque across the board, you should increase HP on the top end.
So the 4-1 headers should help the torque drop off that starts at about 5000, which should lead to higher HP numers, and a truly linear torque curve.
So the 4-1 headers should help the torque drop off that starts at about 5000, which should lead to higher HP numers, and a truly linear torque curve.
05-17-2001, 04:06 PM
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I hope you meant hp = torque times speed(rpm). This is why the better the torque at higher rpm the higher the peak hp. Looking at the curves and from I have read on Tibby performance you have two problems 1)a valley at midrange and 2)a dramatic decrease in torque at higher rpm. I think we all share this. Ok, my theory is that the low torque at high rpm is due to air intake restrictions which is taking a toll on volumetric efficieny. I dont think has a lot to do with exhaust even though it could help I think intake (filter, setup and cams) are to blame. A good intake mod will not only increase torque all across but it will lift or flaten the high end also. Now on header side I would go 4 1 for oval steady high rpm racing, for 400 meter um! I would test to see and for light to light i would go 421 since the torque on the low and midrange gives you much more acceleration at take off and you will not use your 6000+ rpm as much since you have to start decelerating. All given the intake problem has taken care off.
05-17-2001, 04:39 PM
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Mario-
The point that red and I were trying to make is that you will only need that "low end" increase in first gear.
By the time you shift out of first and into second, and all other gear changes, you will be above 3500 rpm, so any increases to the low end will be lost.
The above is assuming full on acceleration. If you are refering to just around town driving, then, yes, the low end to mid range is where you spend most of your time.
The point that red and I were trying to make is that you will only need that "low end" increase in first gear.
By the time you shift out of first and into second, and all other gear changes, you will be above 3500 rpm, so any increases to the low end will be lost.
The above is assuming full on acceleration. If you are refering to just around town driving, then, yes, the low end to mid range is where you spend most of your time.
05-18-2001, 01:03 AM
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Ok I buy that. Good discussion guys thats is what is all about and for everybody to learn from. Hope did not get too rough, no hard feelings Red I enjoyed the discussion.Regards and out!!!