928 GTS Cam upgrade
04-27-2011 | 01:48 PM
#91
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Colin,
That chart is very deceptive in relating the hp to torque. Look at the scales for each and you'll
notice that the torque at 6500 rpm is at 250 ft-lbs, if it were on the same scale as hp, then
it wouldn't drop so dramatically...
Doesn't have any other bearing on the cam discussion, just want to keep things in perspective.
That chart is very deceptive in relating the hp to torque. Look at the scales for each and you'll
notice that the torque at 6500 rpm is at 250 ft-lbs, if it were on the same scale as hp, then
it wouldn't drop so dramatically...
Doesn't have any other bearing on the cam discussion, just want to keep things in perspective.
04-27-2011 | 01:59 PM
#92
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From: saratoga, ca
ok, got the differene of LSA vs cam lift and duration.
yet, i think we are talking past each other here.
I said, getting back to my beginning statement, that when Dennis said, " i want more torque at high rpm". Colin, this means more HP! do you agree? you should. i could care less about the spacing of the peak torque vs the peak HP, all we should care about, is the amplitude and width of the HP curve where it will be used. (as a function of the gear spacing). In otherwords, more HP is a result of more torque in the RPM range you are reviewing.
Now, you say this:
But wait a second, you first say that more HP is a result of more torque at a higher RPM. Then you say that you lost torque, even gone on to say substantially at 4000RPM, yet you gained HP!"
what the heck are you talking about?????? more hp is a result, ENTIRELY, of more torque at ANY rpm. if you have more HP anywhere , you have more torque. Anyone reading this would agree, that they understand, that I lost peak torque and gained peak HP. (two different rpm ranges. in otherwords, peak torque is in the 4000rpm range, yet peak HP is in the 5500 to 6000rpm range). IN OTHER WORDS AGAIN! I lost torque at 4000rpm but gained hp at 6000rpm. make sense???
you want to talk about LSAs, lets keep it to the peaks of hp and torque changing in relation to each other.
you also say that hp is going up as torque is plummeting! yes, this is because HP is related to RPM and torque if HP is going up because he RPM is going up AND the torque is falling .. if it falls fast enough, HP can be flat. if it really falls, then HP will start to fall too. this generally happens after peak HP.
your graphs are all over the place too. first you make up one that made absolutely no sense, even to make a point. (totally fully of errors for comparison)
and now this graph has disparate scales, YET, you reference how fast something (torque) is falling. are you seroius! this is some kind of late APRIL fools joke???
Mark
yet, i think we are talking past each other here.
I said, getting back to my beginning statement, that when Dennis said, " i want more torque at high rpm". Colin, this means more HP! do you agree? you should. i could care less about the spacing of the peak torque vs the peak HP, all we should care about, is the amplitude and width of the HP curve where it will be used. (as a function of the gear spacing). In otherwords, more HP is a result of more torque in the RPM range you are reviewing.
Now, you say this:
But wait a second, you first say that more HP is a result of more torque at a higher RPM. Then you say that you lost torque, even gone on to say substantially at 4000RPM, yet you gained HP!"
what the heck are you talking about?????? more hp is a result, ENTIRELY, of more torque at ANY rpm. if you have more HP anywhere , you have more torque. Anyone reading this would agree, that they understand, that I lost peak torque and gained peak HP. (two different rpm ranges. in otherwords, peak torque is in the 4000rpm range, yet peak HP is in the 5500 to 6000rpm range). IN OTHER WORDS AGAIN! I lost torque at 4000rpm but gained hp at 6000rpm. make sense???
you want to talk about LSAs, lets keep it to the peaks of hp and torque changing in relation to each other.
you also say that hp is going up as torque is plummeting! yes, this is because HP is related to RPM and torque if HP is going up because he RPM is going up AND the torque is falling .. if it falls fast enough, HP can be flat. if it really falls, then HP will start to fall too. this generally happens after peak HP.
your graphs are all over the place too. first you make up one that made absolutely no sense, even to make a point. (totally fully of errors for comparison)
and now this graph has disparate scales, YET, you reference how fast something (torque) is falling. are you seroius! this is some kind of late APRIL fools joke???
Mark
Ken,
Give a little more advance, run 94 octane, and add headers with a full race exhaust.
I have never seen a S4 or GT break 305 RWHP with the stock manifolds, stock airbox, and stock cams. Which is what you are working with.
If you change to headers, full proper exhaust, you will gain some, possibly 15rwhp which is what MK is saying you would see on an S4 (320). Also from my logging, and data that I collected, the S3 intake did restrict power in the top end (just as the S4 does too).
Go back and read again. You might catch it this time, I stated that I pulled my inop flappy (removed the butterfly). But that the chart posted was WITH the inop flappy. This is not hard to folllow Mark.
If you say that the flappy is good for 50BHP, then I would be at 375 right now! I hope your right!
Mark,
We are not discussing changes to a camshaft regarding lift/duration. We are discussing the differences in LSA. Now you talk about contradictions! I just highlighted some of your own words, here.
"my point that more hp is a result of more torque at higher rpm."
"in cam changes for the US 84 for example, (going to the more aggresive euro cams) i lost peak torque, fairly substantial at 4000rpm and gained 30 more hp"
But wait a second, you first say that more HP is a result of more torque at a higher RPM. Then you say that you lost torque, even gone on to say substantially at 4000RPM, yet you gained HP!
You then say;
"more torque up at the high rpm ranges DOES NOT create more HP. IT DOES!"
You are not comprehending what I am saying. A narrower LSA will generate MORE PEAK torque, and MORE peak HP. But their peaks will be at a further apart RPM range.
A wider LSA will have slightly LESS PEAK torque, and LESS PEAK HP. But their peaks will be closer together.
This means that the engine with the wider LSA will have a couple ft lbs less than the narrow LSA, but it will peak at a higher RPM. This is proven time and time again.
And again, this is with NOTHING else changing. Meaning that the cams have the same lift, and duration.
Here is an example of a car with a narrow LSA
Notice how as the HP climbs the torque falls off FAST.
Yet if you looked at earlier chart I posted, you see that it doesnt fall off like this, because it has a wide LSA. Yet this does cost a few HP in the upper RPM.
The big difference between the S4 and S3 was the ign advance. The S4 had knock sensors and ran way more ign. Bringing the S3 up to the same type of curve as the S4 (maybe still even just a tick less), Ken has shown us that the S3 makes just as much as the S4 with everything else being pretty stock.
An S4 with an X pipe makes close to 300rwhp (manual) lets say, Ken is seeing that too with a Y pipe and a stock rear 84 pipe.
Now with regards to changing cams, a cam with more lift/duration will raise two things, peak HP, and to an extent where the peaks are (at what RPM).
A car with less lift/duration (to a point) will generate more peak torque than a engine with a big lift/duration cam. But the big lift duration cam will have a higher peak HP, and yes torque will fall off. It is all a factor of trade offs.
But remember our main discussion was ONLY regarding the differences of LSA, nothing more.
Give a little more advance, run 94 octane, and add headers with a full race exhaust.
I have never seen a S4 or GT break 305 RWHP with the stock manifolds, stock airbox, and stock cams. Which is what you are working with.
If you change to headers, full proper exhaust, you will gain some, possibly 15rwhp which is what MK is saying you would see on an S4 (320). Also from my logging, and data that I collected, the S3 intake did restrict power in the top end (just as the S4 does too).
Go back and read again. You might catch it this time, I stated that I pulled my inop flappy (removed the butterfly). But that the chart posted was WITH the inop flappy. This is not hard to folllow Mark.
If you say that the flappy is good for 50BHP, then I would be at 375 right now! I hope your right!
Mark,
We are not discussing changes to a camshaft regarding lift/duration. We are discussing the differences in LSA. Now you talk about contradictions! I just highlighted some of your own words, here.
"my point that more hp is a result of more torque at higher rpm."
"in cam changes for the US 84 for example, (going to the more aggresive euro cams) i lost peak torque, fairly substantial at 4000rpm and gained 30 more hp"
But wait a second, you first say that more HP is a result of more torque at a higher RPM. Then you say that you lost torque, even gone on to say substantially at 4000RPM, yet you gained HP!
You then say;
"more torque up at the high rpm ranges DOES NOT create more HP. IT DOES!"
You are not comprehending what I am saying. A narrower LSA will generate MORE PEAK torque, and MORE peak HP. But their peaks will be at a further apart RPM range.
A wider LSA will have slightly LESS PEAK torque, and LESS PEAK HP. But their peaks will be closer together.
This means that the engine with the wider LSA will have a couple ft lbs less than the narrow LSA, but it will peak at a higher RPM. This is proven time and time again.
And again, this is with NOTHING else changing. Meaning that the cams have the same lift, and duration.
Here is an example of a car with a narrow LSA
Notice how as the HP climbs the torque falls off FAST.
Yet if you looked at earlier chart I posted, you see that it doesnt fall off like this, because it has a wide LSA. Yet this does cost a few HP in the upper RPM.
The big difference between the S4 and S3 was the ign advance. The S4 had knock sensors and ran way more ign. Bringing the S3 up to the same type of curve as the S4 (maybe still even just a tick less), Ken has shown us that the S3 makes just as much as the S4 with everything else being pretty stock.
An S4 with an X pipe makes close to 300rwhp (manual) lets say, Ken is seeing that too with a Y pipe and a stock rear 84 pipe.
Now with regards to changing cams, a cam with more lift/duration will raise two things, peak HP, and to an extent where the peaks are (at what RPM).
A car with less lift/duration (to a point) will generate more peak torque than a engine with a big lift/duration cam. But the big lift duration cam will have a higher peak HP, and yes torque will fall off. It is all a factor of trade offs.
But remember our main discussion was ONLY regarding the differences of LSA, nothing more.
04-27-2011 | 02:04 PM
#94
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From: saratoga, ca
Colin, look at the Porken graph, that is almost the same shape HP cuve as your example, and look at the torque curve. notice the difference. they should be identical (or near identical). your scales are off on the example you posted thats why things look so weird! (torque falling at such a wild rate) 
04-27-2011 | 04:12 PM
#98
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From: Abbotsford B.C.
Now lets pull some information out of this.
So which is it Mark? I am beginning to think that you dont even comprehend what you are typing.
From your response you bolded a section, read it. You bolded my quotation of you, then you ask what the heck I am talking about.
Lets go over what I am saying.
You have two camshafts with S4 lift and duration. One set of cams has a LSA of 106 deg, the other with 114 deg.
The 106 will have a higher peak torque number and higher peak HP number, however the peaks will be further apart.
The 114 will have slightly less peak Torque and Hp, but their peaks will be closer together.
Forget that previous graph, I only drew that to try and show the PEAK numbers and locations, not the rest of the curve!
From your response you bolded a section, read it. You bolded my quotation of you, then you ask what the heck I am talking about.
Lets go over what I am saying.
You have two camshafts with S4 lift and duration. One set of cams has a LSA of 106 deg, the other with 114 deg.
The 106 will have a higher peak torque number and higher peak HP number, however the peaks will be further apart.
The 114 will have slightly less peak Torque and Hp, but their peaks will be closer together.
Forget that previous graph, I only drew that to try and show the PEAK numbers and locations, not the rest of the curve!
04-27-2011 | 07:33 PM
#99
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let me bang my head against the wall a few times first!
what part of what I said, dont you understand or agree with. both are correct. hp and torque are interlinked via something called "RPM".
if you have more hp (than before) at a higher rpm, then you must have more torque at that rpm. I lost it at 4000rpm. (actually lost HP there) and gained hp (with an increase of torque at 6000rpm) I dont know how much clearer i can be. Its almost like you dont understand the basic equation. you have a handle on the cam stuff but not the basics. so, im confused by you objections. AHH, maybe you need to speak in HP-seconds. is that what you are refering too? time spent in a higher HP range?? area under the curve type analysis???
now, what you say below has nothing to do with what we are talking about.
you are talking about moving the peaks (hp and torque) closer together. thats fine. Remember, the ONLY thing I was saying was that if you have more torque at Higher RPM, you will have more HP. same thing. hp is related to torque x rpm, so they are inextricably tied together.
I said:
quote:Originally Posted by mark kibort
more hp is a result, ENTIRELY, of more torque at ANY rpm. if you have more HP anywhere , you have more torque.
Quote:
Originally Posted by mark kibort
that I lost peak torque and gained peak HP. IN OTHER WORDS AGAIN! I lost torque at 4000rpm but gained hp at
yes , yes yes. the only think could have added to be more clear was to say, "more hp is a result , ENTIRELY, of more torque at any RPM where there is more HP than before." " if you have more HP anywhere, you have more torque at that same coresponding RPM".
the second quote: Yes, i lost peak torque with a more mild cam with more overlap, and gained HP at 6000rpm. that means, I got more torque at 6000rpm. does that make more sense???? This is HP 101 stuff!
what part of what I said, dont you understand or agree with. both are correct. hp and torque are interlinked via something called "RPM".
if you have more hp (than before) at a higher rpm, then you must have more torque at that rpm. I lost it at 4000rpm. (actually lost HP there) and gained hp (with an increase of torque at 6000rpm) I dont know how much clearer i can be. Its almost like you dont understand the basic equation. you have a handle on the cam stuff but not the basics. so, im confused by you objections. AHH, maybe you need to speak in HP-seconds. is that what you are refering too? time spent in a higher HP range?? area under the curve type analysis???
now, what you say below has nothing to do with what we are talking about.
you are talking about moving the peaks (hp and torque) closer together. thats fine. Remember, the ONLY thing I was saying was that if you have more torque at Higher RPM, you will have more HP. same thing. hp is related to torque x rpm, so they are inextricably tied together.
I said:
quote:Originally Posted by mark kibort
more hp is a result, ENTIRELY, of more torque at ANY rpm. if you have more HP anywhere , you have more torque.
Quote:
Originally Posted by mark kibort
that I lost peak torque and gained peak HP. IN OTHER WORDS AGAIN! I lost torque at 4000rpm but gained hp at
yes , yes yes. the only think could have added to be more clear was to say, "more hp is a result , ENTIRELY, of more torque at any RPM where there is more HP than before."
" if you have more HP anywhere, you have more torque at that same coresponding RPM". the second quote: Yes, i lost peak torque with a more mild cam with more overlap, and gained HP at 6000rpm. that means, I got more torque at 6000rpm. does that make more sense???? This is HP 101 stuff!
Now lets pull some information out of this.
So which is it Mark? I am beginning to think that you dont even comprehend what you are typing.
From your response you bolded a section, read it. You bolded my quotation of you, then you ask what the heck I am talking about.
Lets go over what I am saying.
You have two camshafts with S4 lift and duration. One set of cams has a LSA of 106 deg, the other with 114 deg.
The 106 will have a higher peak torque number and higher peak HP number, however the peaks will be further apart.
The 114 will have slightly less peak Torque and Hp, but their peaks will be closer together.
Forget that previous graph, I only drew that to try and show the PEAK numbers and locations, not the rest of the curve!
So which is it Mark? I am beginning to think that you dont even comprehend what you are typing.
From your response you bolded a section, read it. You bolded my quotation of you, then you ask what the heck I am talking about.
Lets go over what I am saying.
You have two camshafts with S4 lift and duration. One set of cams has a LSA of 106 deg, the other with 114 deg.
The 106 will have a higher peak torque number and higher peak HP number, however the peaks will be further apart.
The 114 will have slightly less peak Torque and Hp, but their peaks will be closer together.
Forget that previous graph, I only drew that to try and show the PEAK numbers and locations, not the rest of the curve!
04-27-2011 | 09:52 PM
#100
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04-27-2011 | 10:11 PM
#101
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From: Stockton, CA
Okay I am not an engine builder or engineer.....but I find it odd that the same cams will produce the most peak torque and most peak power BUT the peaks are far apart.....which means 1 cam will produce a mountain of torque down low and hold that curve until really late to produce peak HP...
the other cam that produces a torque and HP peak close together always are later in the RPM band....and since the more torque you have later in RPM that always means more HP.... while it might make slightly less peak torque than the earlier peak torque...since it makes peak torque later it WILL make more HP since it will have more torque later in the RPM band
cams by nature are a compromise.....do you want a rock solid idle, with great drive-abilty down low and crazy HP-torque up top...good luck with that..... most hot rod cams idle like crap and don't do much down low, plus buck like a horse at low speeds....BUT they ROCK at high rpm and make stupid power....there is no way around this....
Bottom line is engines are an assembly...everything MUST work together.... it all depends on your goals for your engine.....
the other cam that produces a torque and HP peak close together always are later in the RPM band....and since the more torque you have later in RPM that always means more HP.... while it might make slightly less peak torque than the earlier peak torque...since it makes peak torque later it WILL make more HP since it will have more torque later in the RPM band
cams by nature are a compromise.....do you want a rock solid idle, with great drive-abilty down low and crazy HP-torque up top...good luck with that..... most hot rod cams idle like crap and don't do much down low, plus buck like a horse at low speeds....BUT they ROCK at high rpm and make stupid power....there is no way around this....
Bottom line is engines are an assembly...everything MUST work together.... it all depends on your goals for your engine.....
04-27-2011 | 10:25 PM
#102
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From: Anaheim
And according to Kibort...all dynos read the same, since they are calibrated the same....it's just a given drum accelerating at a measured speed.
Whatever numbers come out of the printer have to be true!
I'm still dying to run one of my 330rwhp strokers against Dennis's 375rwhp 5.0, BTW. (Kibort has not explained how we sucked the door ***** off of the 575rwhp supercharged GTS with one of these tame little 330rwhp things....)
You know, Rob Edwards just told me that he is going to go to the Sharks in the Park thing, this year....maybe we can "gather some data"!
Whatever numbers come out of the printer have to be true!
I'm still dying to run one of my 330rwhp strokers against Dennis's 375rwhp 5.0, BTW. (Kibort has not explained how we sucked the door ***** off of the 575rwhp supercharged GTS with one of these tame little 330rwhp things....)
You know, Rob Edwards just told me that he is going to go to the Sharks in the Park thing, this year....maybe we can "gather some data"!
04-27-2011 | 10:32 PM
#103
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And according to Kibort...all dynos read the same, since they are calibrated the same....it's just a given drum accelerating at a measured speed.
Whatever numbers come out of the printer have to be true!
I'm still dying to run one of my 330rwhp strokers against Dennis's 375rwhp 5.0, BTW. (Kibort has not explained how we sucked the door ***** off of the 575rwhp supercharged GTS with one of these tame little 330rwhp things....)
You know, Rob Edwards just told me that he is going to go to the Sharks in the Park thing, this year....maybe we can "gather some data"!
Whatever numbers come out of the printer have to be true!
I'm still dying to run one of my 330rwhp strokers against Dennis's 375rwhp 5.0, BTW. (Kibort has not explained how we sucked the door ***** off of the 575rwhp supercharged GTS with one of these tame little 330rwhp things....)
You know, Rob Edwards just told me that he is going to go to the Sharks in the Park thing, this year....maybe we can "gather some data"!
The engines you run, have a higher 'kiborts'. This is when the torque is higher than the horsepower at a given time in the RPM band. If x over y is nowhere near z, then k is no longer a factor which in turn means absolutely nothing because you were not running an electric supercharger lubed by Amzoil.
So, that is why 330 is larger than 575 in real world tests.
04-27-2011 | 10:55 PM
#104
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From: Oklahoma
And according to Kibort...all dynos read the same, since they are calibrated the same....it's just a given drum accelerating at a measured speed.
Whatever numbers come out of the printer have to be true!
I'm still dying to run one of my 330rwhp strokers against Dennis's 375rwhp 5.0, BTW. (Kibort has not explained how we sucked the door ***** off of the 575rwhp supercharged GTS with one of these tame little 330rwhp things....)
You know, Rob Edwards just told me that he is going to go to the Sharks in the Park thing, this year....maybe we can "gather some data"!
Whatever numbers come out of the printer have to be true!
I'm still dying to run one of my 330rwhp strokers against Dennis's 375rwhp 5.0, BTW. (Kibort has not explained how we sucked the door ***** off of the 575rwhp supercharged GTS with one of these tame little 330rwhp things....)
You know, Rob Edwards just told me that he is going to go to the Sharks in the Park thing, this year....maybe we can "gather some data"!
I also agree with you that there's a lot more to overall vehicle performance than a single top-end number.
04-27-2011 | 11:24 PM
#105
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From: Anaheim
Don't get me wrong. I, too, was skeptical of my results from this dyno. However, as a sort of control factor, I would note a well maintained '91 S4 automatic with a X-pipe only did 282rwhp. This number seemed quite reasonable - leading me to believe the higher results of my stock GT, as well as those of the modified GT's, were legit.
I also agree with you that there's a lot more to overall vehicle performance than a single top-end number.
I also agree with you that there's a lot more to overall vehicle performance than a single top-end number.