Injected Performance: Cosworth dyno test at 7000+rpm FI
08-19-2009, 07:13 AM
#121
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ya, but the spacer gains were in the stock powerband (under 6500 rpms). The cosworth isnt making 1000$ worth of extra power under 6500 rpms. Above 7300+, it looks great though.
Seems aggro cams and 7500+ rpm redline are in order for the Cosworth to shine.
So you dont need to move the Cosworth at all do change the plugs. Thats really nice.
Seems aggro cams and 7500+ rpm redline are in order for the Cosworth to shine.
So you dont need to move the Cosworth at all do change the plugs. Thats really nice.
CJM is coming out with a Plenum and it looks badazz......If you cant rev over 7K+......dont even bother. But I know that because it looks good....you will have people that would give up power just to say they have it.I cant blame them....
Yeah...with the Cosworth....you can change the plugs without removing the plenum
I'm going to speculate that the rpms at which the Cosworth comes alive is dependent on the rest of the setup. On my build we had JWT C2 cams, and we picked up HP lower in the rpm range. I do say this with hesitation, though, because when we added the Cosworth we also added turbo blankets, the pathfinder cooling mod, and other little tweaks here and there.
Last edited by XKR; 08-19-2009 at 07:23 AM.
08-19-2009, 07:45 AM
#122
Here are my dyno plots with both the Motordyne spacer and the Cosworth plenum. Unfortunately, these are at different boost levels and with the changes noted above.
Notes:
1. The first one was run on a hot day. Measured RWHP was in the 550's but it weather corrected up to 584 RWHP. The second run was on a moderate day, it measured 609 RWHP, but weather corrected down to 603 RWHP.
2. The person on the first tune (Jack) opened the throttle later than the person doing the second tune (Roger).
3. The dip in the second plot at around 4200 rpm was intentional. The timing was pulled back here and we ran it a little on the rich side to provide safety margin. I was supposed to run homestead the next day (I over-reved the motor playing with WOT shifting, so I didn't make it).
4. I think the torque plateu at 5000 - 5600 rpm is due to the cosworth. Specifically, I venture to say that this is the rpm range at which the Cosworth intake runners are tuned.
Notes:
1. The first one was run on a hot day. Measured RWHP was in the 550's but it weather corrected up to 584 RWHP. The second run was on a moderate day, it measured 609 RWHP, but weather corrected down to 603 RWHP.
2. The person on the first tune (Jack) opened the throttle later than the person doing the second tune (Roger).
3. The dip in the second plot at around 4200 rpm was intentional. The timing was pulled back here and we ran it a little on the rich side to provide safety margin. I was supposed to run homestead the next day (I over-reved the motor playing with WOT shifting, so I didn't make it).
4. I think the torque plateu at 5000 - 5600 rpm is due to the cosworth. Specifically, I venture to say that this is the rpm range at which the Cosworth intake runners are tuned.
Last edited by RudeG_v2.0; 08-19-2009 at 07:51 AM.
08-19-2009, 08:06 AM
#123
Ignoring the respective torque/hp levels, you can clearly see the torque curve flattening out between 5000 and 5600 rpm in the second dyno. In the first dyno, the torque curve continues to fall. This difference, I beleive, is due to the Cosworth plenum being used in the second dyno. Without the Cosworth, the torque would continue to drop in this range.
So, although this comparison is far from ideal, it still provides some useful information.
08-19-2009, 09:46 AM
#125
I don't doubt that the Cosworth manifold makes more power than a stock plenum without spacer. I just would like to see more independent back to back tests of it versus a spacer.
All the dynos that have been posted for the Cosworth thus far have been relatively moderate power/moderate PSI builds revved past 7000RPM... and it seems to shine in those applications (which is a growing segment in the VQ aftermarket).
It's also a great piece of eye candy/engine bay bling for the car show crowd. I'm just skeptical of the Cosworth's performance superiority in true high power/high boost setups and don't want to see it get fluffed/hyped for "big dawg" builds or "high power". The VQ community's definition of "high power" and "high boost" is weaksauce compared to other platforms that routinely run 30+PSI of boost.
The main reason for my skepticism about the Cosworth manifold in high boost applications is it's internal design with the velocity stacks/air horns inside of the plenum. It reminds me of the interior of the Veilside plenum for the 2JZ(Supra) which was proven to be an inferior performer to the Virtual Works plenum. They look very similar externally, but the Virtual works does not have the internal complexity of velocity stacks. It has simple smooth inlets into the runners instead (kinda like the CJM intake manifold for the VQ) and it outflows the Veilside by a significant margin. Therefore, I have similar concerns about the Cosworth intake manifold. I think the CJM intake will outflow the Cosworth and IMO a performance comparison between the two would be akin to the Veilside/Virtual Works experience in the Supra community.
Here is the link on Supra forums with an impartial comparison in the OP between the two including flow bench numbers:
http://www.supraforums.com/forum/sho...hreadid=166026
All the dynos that have been posted for the Cosworth thus far have been relatively moderate power/moderate PSI builds revved past 7000RPM... and it seems to shine in those applications (which is a growing segment in the VQ aftermarket).
It's also a great piece of eye candy/engine bay bling for the car show crowd. I'm just skeptical of the Cosworth's performance superiority in true high power/high boost setups and don't want to see it get fluffed/hyped for "big dawg" builds or "high power". The VQ community's definition of "high power" and "high boost" is weaksauce compared to other platforms that routinely run 30+PSI of boost. The main reason for my skepticism about the Cosworth manifold in high boost applications is it's internal design with the velocity stacks/air horns inside of the plenum. It reminds me of the interior of the Veilside plenum for the 2JZ(Supra) which was proven to be an inferior performer to the Virtual Works plenum. They look very similar externally, but the Virtual works does not have the internal complexity of velocity stacks. It has simple smooth inlets into the runners instead (kinda like the CJM intake manifold for the VQ) and it outflows the Veilside by a significant margin. Therefore, I have similar concerns about the Cosworth intake manifold. I think the CJM intake will outflow the Cosworth and IMO a performance comparison between the two would be akin to the Veilside/Virtual Works experience in the Supra community.
Here is the link on Supra forums with an impartial comparison in the OP between the two including flow bench numbers:
http://www.supraforums.com/forum/sho...hreadid=166026
Last edited by RudeG_v2.0; 08-19-2009 at 10:08 AM.
08-19-2009, 10:21 AM
#127
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I bet YOU could......but remember I am talking about me...I have zero wrench skills
Dont get me wrong....I understand what you are saying..... No doubt that CJM will kick azz...When Charles sends us his plenum.... we will do a CJM vs Cos......I have seen CJM's new version....and its quite easy to see that it will blow the Cosworth away.....Charles already told me that it will only work with high reving big Powa...
....Now that I think of it...I think Charles was insulting me 
I don't doubt that the Cosworth manifold makes more power than a stock plenum without spacer. I just would like to see more independent back to back tests of it versus a spacer.
All the dynos that have been posted for the Cosworth thus far have been relatively moderate power/moderate PSI builds revved past 7000RPM... and it seems to shine in those applications (which is a growing segment in the VQ aftermarket). It's also a great piece of eye candy/engine bay bling for the car show crowd. I'm just skeptical of the Cosworth's performance superiority in true high power/high boost setups and don't want to see it get fluffed/hyped for "big dawg" builds or "high power". The VQ community's definition of "high power" and "high boost" is weaksauce compared to other platforms that routinely run 30+PSI of boost.
The main reason for my skepticism about the Cosworth manifold in high boost applications is it's internal design with the velocity stacks/air horns inside of the plenum. It reminds me of the interior of the Veilside plenum for the 2JZ(Supra) which was proven to be an inferior performer to the Virtual Works plenum. They look very similar externally, but the Virtual works does not have the internal complexity of velocity stacks. It has simple smooth inlets into the runners instead (kinda like the CJM intake manifold for the VQ) and it outflows the Veilside by a significant margin. Therefore, I have similar concerns about the Cosworth intake manifold. I think the CJM intake will outflow the Cosworth and IMO a performance comparison between the two would be akin to the Veilside/Virtual Works experience in the Supra community.
Here is the link on Supra forums with an impartial comparison in the OP between the two including flow bench numbers:
http://www.supraforums.com/forum/sho...hreadid=166026
All the dynos that have been posted for the Cosworth thus far have been relatively moderate power/moderate PSI builds revved past 7000RPM... and it seems to shine in those applications (which is a growing segment in the VQ aftermarket).
It's also a great piece of eye candy/engine bay bling for the car show crowd. I'm just skeptical of the Cosworth's performance superiority in true high power/high boost setups and don't want to see it get fluffed/hyped for "big dawg" builds or "high power". The VQ community's definition of "high power" and "high boost" is weaksauce compared to other platforms that routinely run 30+PSI of boost. The main reason for my skepticism about the Cosworth manifold in high boost applications is it's internal design with the velocity stacks/air horns inside of the plenum. It reminds me of the interior of the Veilside plenum for the 2JZ(Supra) which was proven to be an inferior performer to the Virtual Works plenum. They look very similar externally, but the Virtual works does not have the internal complexity of velocity stacks. It has simple smooth inlets into the runners instead (kinda like the CJM intake manifold for the VQ) and it outflows the Veilside by a significant margin. Therefore, I have similar concerns about the Cosworth intake manifold. I think the CJM intake will outflow the Cosworth and IMO a performance comparison between the two would be akin to the Veilside/Virtual Works experience in the Supra community.
Here is the link on Supra forums with an impartial comparison in the OP between the two including flow bench numbers:
http://www.supraforums.com/forum/sho...hreadid=166026
....Now that I think of it...I think Charles was insulting me
Last edited by XKR; 08-19-2009 at 10:37 AM.
08-19-2009, 11:14 AM
#129
Well XKR will be one of the 1st high boost, high power, high rev motors that wont be a drag queen.
Once he gets some dyno's, that will indicate where I should head with my 3.5L build, which I also plan to run to 7500 rpms at 28psi at the strip. $1000 is a good bit to spend, but if it really makes 40-60 whp with nothing else changed, thats pretty good $/hp.
Once he gets some dyno's, that will indicate where I should head with my 3.5L build, which I also plan to run to 7500 rpms at 28psi at the strip. $1000 is a good bit to spend, but if it really makes 40-60 whp with nothing else changed, thats pretty good $/hp.
08-19-2009, 11:22 AM
#130
I agree - $1000 is nothing in my opinion for an ADDITIONAL 40+whp at these power levels. I have told a number of people here that if I could just keep spending $1000 and gaining 40whp without any losses, ON THE SAME FUEL... I would continue to do so forever.
08-19-2009, 11:43 AM
#131
I don't doubt that the Cosworth manifold makes more power than a stock plenum without spacer. I just would like to see more independent back to back tests of it versus a spacer.
All the dynos that have been posted for the Cosworth thus far have been relatively moderate power/moderate PSI builds revved past 7000RPM... and it seems to shine in those applications (which is a growing segment in the VQ aftermarket). It's also a great piece of eye candy/engine bay bling for the car show crowd. I'm just skeptical of the Cosworth's performance superiority in true high power/high boost setups and don't want to see it get fluffed/hyped for "big dawg" builds or "high power". The VQ community's definition of "high power" and "high boost" is weaksauce compared to other platforms that routinely run 30+PSI of boost.
The main reason for my skepticism about the Cosworth manifold in high boost applications is it's internal design with the velocity stacks/air horns inside of the plenum. It reminds me of the interior of the Veilside plenum for the 2JZ(Supra) which was proven to be an inferior performer to the Virtual Works plenum. They look very similar externally, but the Virtual works does not have the internal complexity of velocity stacks. It has simple smooth inlets into the runners instead (kinda like the CJM intake manifold for the VQ) and it outflows the Veilside by a significant margin. Therefore, I have similar concerns about the Cosworth intake manifold. I think the CJM intake will outflow the Cosworth and IMO a performance comparison between the two would be akin to the Veilside/Virtual Works experience in the Supra community.
Here is the link on Supra forums with an impartial comparison in the OP between the two including flow bench numbers:
http://www.supraforums.com/forum/sho...hreadid=166026
All the dynos that have been posted for the Cosworth thus far have been relatively moderate power/moderate PSI builds revved past 7000RPM... and it seems to shine in those applications (which is a growing segment in the VQ aftermarket).
It's also a great piece of eye candy/engine bay bling for the car show crowd. I'm just skeptical of the Cosworth's performance superiority in true high power/high boost setups and don't want to see it get fluffed/hyped for "big dawg" builds or "high power". The VQ community's definition of "high power" and "high boost" is weaksauce compared to other platforms that routinely run 30+PSI of boost. The main reason for my skepticism about the Cosworth manifold in high boost applications is it's internal design with the velocity stacks/air horns inside of the plenum. It reminds me of the interior of the Veilside plenum for the 2JZ(Supra) which was proven to be an inferior performer to the Virtual Works plenum. They look very similar externally, but the Virtual works does not have the internal complexity of velocity stacks. It has simple smooth inlets into the runners instead (kinda like the CJM intake manifold for the VQ) and it outflows the Veilside by a significant margin. Therefore, I have similar concerns about the Cosworth intake manifold. I think the CJM intake will outflow the Cosworth and IMO a performance comparison between the two would be akin to the Veilside/Virtual Works experience in the Supra community.
Here is the link on Supra forums with an impartial comparison in the OP between the two including flow bench numbers:
http://www.supraforums.com/forum/sho...hreadid=166026
http://www.cosworthusa.com/store/pc/...2&idproduct=89
As you noted, the "Virtual works does not have the internal complexity of velocity stacks". This is a very, very important point. Since the Virtual works does not have velocity stacks, it's design is not comparable to the Cosworth.
The velocity stacks are very important. Essentually, they are tuned to resonate at a particular frequency, which corresponds to a particular RPM. The torque at that RPM should therefore improve over the base plenum. Based on my 2nd dyno graph, I would anticipate that one of the sub-harmonics of the resonant frequency corresonds to somewhere around 5300 rpm.
In addition, the velocity stacks have a larger cross section than the stock plenum, which allows for greater air flow at high rpms, which is shown in Hal's dyno comparison.
With respect to the Motordyne spacer/stock plenum, the Cosworth will flow more air under high boost, which relates to more HP. Here is what Hydrazine (owner of Motordyne) said about this subjet in response to a question I posted for him over a year ago:
"The MREV2/spacer combination is clearly better optimized while NA but if you are running high boost @ 20 psi, use the Cosworth.
High boost is where the Cosworth works best.
I don't know about low or medium boost though. I would have to see more data to know where the boost pressure crossover point is between the MREV2 and Cosworth. ...and there isn't much data available."
Here is that link: https://my350z.com/forum/intake-exha...plenums-7.html
Last edited by ttg35fort; 08-22-2009 at 09:55 AM.
08-19-2009, 12:02 PM
#132
Here is a link to Cosworth's CFD Analysis.
http://www.cosworthusa.com/store/pc/...2&idproduct=89
As you noted, the "Virtual works does not have the internal complexity of velocity stacks". This is a very, very important point. Since the Virtual works does not have velocity stacks, it's design is not comparable to the Cosworth.
The velocity stacks are very important. Essentually, they are tuned to resonate at a particular frequency, which corresponds to a particular RPM. The torque at that RPM should therefore improve over the base plenum. Based on my 2nd dyno graph, I would anticipate that the resonant frequency corresonds to somewhere around 5300 rpm.
In addition, the velocity stacks have a larger cross section than the stock plenum, which allows for greater air flow at high rpms, which is shown in Hal's dyno comparison.
With respect to the Motordyne spacer/stock plenum, the Cosworth will flow more air under high boost, which relates to more HP. Here is what Hydrazine (owner of Motordyne) said about this subjet in response to a question I posted for him over a year ago:
"The MREV2/spacer combination is clearly better optimized while NA but if you are running high boost @ 20 psi, use the Cosworth.
High boost is where the Cosworth works best.
I don't know about low or medium boost though. I would have to see more data to know where the boost pressure crossover point is between the MREV2 and Cosworth. ...and there isn't much data available."
Here is that link: https://my350z.com/forum/intake-exha...plenums-7.html
http://www.cosworthusa.com/store/pc/...2&idproduct=89
As you noted, the "Virtual works does not have the internal complexity of velocity stacks". This is a very, very important point. Since the Virtual works does not have velocity stacks, it's design is not comparable to the Cosworth.
The velocity stacks are very important. Essentually, they are tuned to resonate at a particular frequency, which corresponds to a particular RPM. The torque at that RPM should therefore improve over the base plenum. Based on my 2nd dyno graph, I would anticipate that the resonant frequency corresonds to somewhere around 5300 rpm.
In addition, the velocity stacks have a larger cross section than the stock plenum, which allows for greater air flow at high rpms, which is shown in Hal's dyno comparison.
With respect to the Motordyne spacer/stock plenum, the Cosworth will flow more air under high boost, which relates to more HP. Here is what Hydrazine (owner of Motordyne) said about this subjet in response to a question I posted for him over a year ago:
"The MREV2/spacer combination is clearly better optimized while NA but if you are running high boost @ 20 psi, use the Cosworth.
High boost is where the Cosworth works best.
I don't know about low or medium boost though. I would have to see more data to know where the boost pressure crossover point is between the MREV2 and Cosworth. ...and there isn't much data available."
Here is that link: https://my350z.com/forum/intake-exha...plenums-7.html
LOL So I guess the Supra guys got it all wrong.
Just how good is this manifold? Ask the owners of the fastest and most powerful Supras in the world.
● Marko D'Juric's 8 Second Supra
● Ryan Woon's 6 speed 8 Second Supra
● Saad Saad's 1453whp Supra
● Titan Motorsports World's Fastest Street Tire Supra
● Virtual Works 8 Second Supra<O
</O
The world's most powerful 6 speed Supra and the worlds most powerful auto Supra use the VWR Intake manifold.
Want some real numbers? Check out this independent review of the VWR intake manifold vs. The Veilside intake manifold. <O></O>
Download the review here
● Marko D'Juric's 8 Second Supra
● Ryan Woon's 6 speed 8 Second Supra
● Saad Saad's 1453whp Supra
● Titan Motorsports World's Fastest Street Tire Supra
● Virtual Works 8 Second Supra<O
</OThe world's most powerful 6 speed Supra and the worlds most powerful auto Supra use the VWR Intake manifold.
Want some real numbers? Check out this independent review of the VWR intake manifold vs. The Veilside intake manifold. <O
></O>Download the review here
The experience of the Supra community with an intake manifold without velocity stacks inside the plenum trumps what you are citing IMO.
Last edited by RudeG_v2.0; 08-19-2009 at 12:08 PM.
08-19-2009, 12:18 PM
#133
^^
I went back and re-read your post. I mis-read what you were saying the first time about the Virtual Works and Veilside plenums.
It would have been much simpler and cheaper for Cosworth to design the plenum without velocity stacks/runners. They used velocity stacks for a reason/runners. Without the velocity stacks/runners, mid-range torque will suffer, although high RPM performance will be good. It's a trade-off.
EDIT: For those who come accross this thread when researching, the Cosworth uses integrated velocity stacks/runners. I previously referred to these just as velocity stacks, but that is incorrect in the context of the Cosworth plenum.
I went back and re-read your post. I mis-read what you were saying the first time about the Virtual Works and Veilside plenums.
It would have been much simpler and cheaper for Cosworth to design the plenum without velocity stacks/runners. They used velocity stacks for a reason/runners. Without the velocity stacks/runners, mid-range torque will suffer, although high RPM performance will be good. It's a trade-off.
EDIT: For those who come accross this thread when researching, the Cosworth uses integrated velocity stacks/runners. I previously referred to these just as velocity stacks, but that is incorrect in the context of the Cosworth plenum.
Last edited by ttg35fort; 08-22-2009 at 09:23 AM.
08-19-2009, 12:34 PM
#134
^^
I went back and re-read your post. I mis-read what you were saying the first time about the Virtual Works and Veilside plenums.
It would have been much simpler and cheaper for Cosworth to design the plenum without velocity stacks. They used velocity stacks for a reason. Without the velocity stacks, mid-range torque will suffer, although high RPM performance will be good. It's a trade-off.
I went back and re-read your post. I mis-read what you were saying the first time about the Virtual Works and Veilside plenums.
It would have been much simpler and cheaper for Cosworth to design the plenum without velocity stacks. They used velocity stacks for a reason. Without the velocity stacks, mid-range torque will suffer, although high RPM performance will be good. It's a trade-off.
Yep, agreed.
It is a trade-off. Which is why I said that the Cosworth seems well suited for moderate power setups to 7500RPM. CJM's intake is more suited to the high power drag setups. It's also why Charles has been very up front about his plenum not being designed for low-midrange power increases and being intended for high revving high boost/power setups. His version 1 plenum shines from 6000 to above 8000RPM on SP's shop Z.
Last edited by RudeG_v2.0; 08-19-2009 at 12:42 PM.
08-19-2009, 12:52 PM
#135
Ahh, OK.
Yep, agreed. It is a trade-off. Which is why I said that the Cosworth seems well suited for moderate power setups to 7500RPM. CJM's intake is more suited to the high power drag setups. It's also why Charles has been very up front about his plenum not being designed for low-midrange power increases and being intended for high revving high boost/power setups. His version 1 plenum shines from 6000 to above 8000RPM on SP's shop Z.
Yep, agreed.
It is a trade-off. Which is why I said that the Cosworth seems well suited for moderate power setups to 7500RPM. CJM's intake is more suited to the high power drag setups. It's also why Charles has been very up front about his plenum not being designed for low-midrange power increases and being intended for high revving high boost/power setups. His version 1 plenum shines from 6000 to above 8000RPM on SP's shop Z.If we are lucky, maybe Mike and Sharif will share a dyno plot showing the comparison of the CJM plenum to the Cosworth plenum...... (hint, hint, hint).
Last edited by ttg35fort; 08-19-2009 at 12:55 PM.
08-19-2009, 01:41 PM
#136
RudeG_v2.0, I went back and read the report on the flow test that was performed on the Virtual Works and Veilside plenums.
One question that I have that they do not answer is whether the test was performed using a steady state (i.e. constant) air flow, or they simulated the opening and closing of the intake valves? If a steady state air flow was used, the results are dubioius becuase they will not accurately depict the respective performances of the intake manifolds on a real engine with intake valves that are opening and closing. With a steady state air flow, the runners/velocity stacks that have the highest cross-section/length ratio will provide the greatest air flow. In an operating motor, things get much more complicated.
When the intake valve is opening and closing, a resonance is setup in the intake charge. A properly designed intake runner/velocity stack will tune that resonance to a frequency having a sub-harmonic that corresponds to a desired rpm/cam duration, which maximizes the intake air velocity, and thus torque, at that rpm. If the testing performed on the intake plenums did not simulate the opening and closing of the intake valve, then the intake runners/velocity stacks would not be given a chance to do their job.
For those who know a little about sub-woofer boxes, the operation of a velocity stack is somewhat analogous to the operation of a port. The longer the velocity stack, the lower the resonant frequency. EDIT: Also, the volume of the intake plenum is somewhat alalogous to the volume of the sub-woofer box.
One question that I have that they do not answer is whether the test was performed using a steady state (i.e. constant) air flow, or they simulated the opening and closing of the intake valves? If a steady state air flow was used, the results are dubioius becuase they will not accurately depict the respective performances of the intake manifolds on a real engine with intake valves that are opening and closing. With a steady state air flow, the runners/velocity stacks that have the highest cross-section/length ratio will provide the greatest air flow. In an operating motor, things get much more complicated.
When the intake valve is opening and closing, a resonance is setup in the intake charge. A properly designed intake runner/velocity stack will tune that resonance to a frequency having a sub-harmonic that corresponds to a desired rpm/cam duration, which maximizes the intake air velocity, and thus torque, at that rpm. If the testing performed on the intake plenums did not simulate the opening and closing of the intake valve, then the intake runners/velocity stacks would not be given a chance to do their job.
For those who know a little about sub-woofer boxes, the operation of a velocity stack is somewhat analogous to the operation of a port. The longer the velocity stack, the lower the resonant frequency. EDIT: Also, the volume of the intake plenum is somewhat alalogous to the volume of the sub-woofer box.
Last edited by ttg35fort; 08-22-2009 at 09:56 AM.
08-19-2009, 02:19 PM
#137
Our manifold may or may not make good midrange on a boosted application... We wil know more after it's been on a couple different setups. For now we have arranged for back to back testing vs the cosworth on a mid 700hp car that can rev decently high tho not as high as SPs car. Hopefully have results in maybe 2 weeks. Just gotta work up the nerve to ship out the one and only currently finished front throttle manifold we have... So much time and money in it!
08-19-2009, 02:37 PM
#138
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Our manifold may or may not make good midrange on a boosted application... We wil know more after it's been on a couple different setups. For now we have arranged for back to back testing vs the cosworth on a mid 700hp car that can rev decently high tho not as high as SPs car. Hopefully have results in maybe 2 weeks. Just gotta work up the nerve to ship out the one and only currently finished front throttle manifold we have... So much time and money in it!
08-19-2009, 02:43 PM
#139
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only prob is what do you gauge against then???
best bet is 60-120 with whatever vbox setup they are using these days....
and hey, my car does ok on stock plenum...with stock cams lol
tom
best bet is 60-120 with whatever vbox setup they are using these days....
and hey, my car does ok on stock plenum...with stock cams lol
tom
08-20-2009, 05:14 PM
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<a href="http://en.wikipedia.org/wiki/Correlation_does_not_imply_causation"> Correlation does not imply causation.</a>
With an intake manifold, the length of the primary runners ultimately determines the resonant frequencies (rpms) that a manifold is effective at, although there is a multitude of factors that end up making the final torque curve of an engine, or even how effective a specific intake manifold is.
For instance you could have a manifold with proper primary runner lengths, but have the runners be too narrow and a terrible plenum design feeding them.
However, concerning the flow of a fluid from a plenum into a pipe, a properly designed velocity stack will <a href="http://www.profblairandassociates.com/pdfs/Bellmouth.zip">always maximize the flow.</a>
With an intake manifold, the length of the primary runners ultimately determines the resonant frequencies (rpms) that a manifold is effective at, although there is a multitude of factors that end up making the final torque curve of an engine, or even how effective a specific intake manifold is.
For instance you could have a manifold with proper primary runner lengths, but have the runners be too narrow and a terrible plenum design feeding them.
However, concerning the flow of a fluid from a plenum into a pipe, a properly designed velocity stack will <a href="http://www.profblairandassociates.com/pdfs/Bellmouth.zip">always maximize the flow.</a>