Pushing some new intake manifolds to the limit!
Jan 11, 2008, 07:54 AM
#316
NOt to nit-pick or anything, but actually having 2 different lengths of runners on the motor can help broaden the effect of the helmholtz effect... Suzuki has great luck with this on the GSXR engines, where the center two runner are nearly an inch and a half longer than the outer two... It does lessen the effect at a specific rpm, but it will spread out that range it does effect...
IIRC the gsxr750 's two lengths were tuned for 9700 rpms and 10,300..... ( i think)
IIRC the gsxr750 's two lengths were tuned for 9700 rpms and 10,300..... ( i think)
with the bike theory in mind its also fed from the center and not the side of the airbox and the 2 taller stacks in the center create more mid range where as if you switch them out for all short stacks you get more top end.. of course this is allmotor so i dont know how it would apply to boost exactly..
Jan 11, 2008, 07:55 AM
#317
Would a manifold built nearly the same as the exhaust manifold be more efficient for drag racing? Center, topmounted TB, equal length runners to the head? How necessary is the plenum when drag racing?
edit: USPmotorsports and I must be on the same wavelength, posted this before seeing his.
edit: USPmotorsports and I must be on the same wavelength, posted this before seeing his.
Jan 11, 2008, 08:43 AM
#318
I have seen the attempt on designing an intake manifold like and exh manifold.. You need the plenum for volume.. even with a bike you have a huge airbox.. I think it has something to do with airspeed on exhuast side but volume on the intake side.. IDK for sure..
Jan 11, 2008, 09:04 AM
#319
dei and ted b. while I have no idea what a hemmedskirt theory is I do get by in life with my redneck methods
With that said, the header testing for me is hard to swallow as I found the opposite. Of about 6 headers/manifolds we tested the one that worked best bolted to the head on the flow bench definetely worked best on the track, hands down.
The intake manifold, in a naturally aspirated application, I can understand and accept it might not carrying over and I even said that in my post. You could for sure tell which one flowed best on the flow bench though bolted to the head. So with what DEI said about his testing methods I tend to agree with him that once that plenum is packed full of boost it seems as though it will equalize. This would also seem to hold true from the bench testing to the track from what I have seen.
I am not argueing just making the statements I have done testing on both sides (intake and exhaust) bolted to a head and run on flow benches and then raced what worked best. I'd say over the years I've been successful and set a record or two.
Is there a more technical-book-way-of-doing-it? I'm sure there is. There's probably even some fancy terms to call all of it. Those things I'm not familar with me and Larry just "Git r done!"
With that said, the header testing for me is hard to swallow as I found the opposite. Of about 6 headers/manifolds we tested the one that worked best bolted to the head on the flow bench definetely worked best on the track, hands down.
The intake manifold, in a naturally aspirated application, I can understand and accept it might not carrying over and I even said that in my post. You could for sure tell which one flowed best on the flow bench though bolted to the head. So with what DEI said about his testing methods I tend to agree with him that once that plenum is packed full of boost it seems as though it will equalize. This would also seem to hold true from the bench testing to the track from what I have seen.
I am not argueing just making the statements I have done testing on both sides (intake and exhaust) bolted to a head and run on flow benches and then raced what worked best. I'd say over the years I've been successful and set a record or two.
Is there a more technical-book-way-of-doing-it? I'm sure there is. There's probably even some fancy terms to call all of it. Those things I'm not familar with me and Larry just "Git r done!"
Jan 11, 2008, 09:25 AM
#320
USP, I had Burns stainless build me one of their header collectors in aluminum for an intake manifold I wanted to build. One of them I sent out to a company who has an intake manifold that doesn't work to try and get him to use the idea I had to build one that did. Nothing ever came of it, I have another one of them here.
I was watching some show a few weeks ago with a guy who had a Mustang with the same idea on it. Crazy looking, basically a header for the intake manifold. He said he dyno'd the car both ways and it made the same power as it did compared to his old intake but the one he had looked so crazy and drew so much attention he kept running it.
I was watching some show a few weeks ago with a guy who had a Mustang with the same idea on it. Crazy looking, basically a header for the intake manifold. He said he dyno'd the car both ways and it made the same power as it did compared to his old intake but the one he had looked so crazy and drew so much attention he kept running it.
Jan 11, 2008, 10:02 AM
#322
Evolved Member
iTrader: (15)
Join Date: Jan 2004
Location: "Tri-Cities" WA
Posts: 1,493
Likes: 0
Received 0 Likes
on
0 Posts
USP, I had Burns stainless build me one of their header collectors in aluminum for an intake manifold I wanted to build. One of them I sent out to a company who has an intake manifold that doesn't work to try and get him to use the idea I had to build one that did. Nothing ever came of it, I have another one of them here.
I was watching some show a few weeks ago with a guy who had a Mustang with the same idea on it. Crazy looking, basically a header for the intake manifold. He said he dyno'd the car both ways and it made the same power as it did compared to his old intake but the one he had looked so crazy and drew so much attention he kept running it.
I was watching some show a few weeks ago with a guy who had a Mustang with the same idea on it. Crazy looking, basically a header for the intake manifold. He said he dyno'd the car both ways and it made the same power as it did compared to his old intake but the one he had looked so crazy and drew so much attention he kept running it.
Chris
Jan 11, 2008, 10:15 AM
#323
Account Disabled
Join Date: Nov 2006
Location: Akron, Ohio
Posts: 174
Likes: 0
Received 0 Likes
on
0 Posts
Quote:
Originally Posted by 4G63DSM
NOt to nit-pick or anything, but actually having 2 different lengths of runners on the motor can help broaden the effect of the helmholtz effect... Suzuki has great luck with this on the GSXR engines, where the center two runner are nearly an inch and a half longer than the outer two... It does lessen the effect at a specific rpm, but it will spread out that range it does effect...
IIRC the gsxr750 's two lengths were tuned for 9700 rpms and 10,300..... ( i think)
with the bike theory in mind its also fed from the center and not the side of the airbox and the 2 taller stacks in the center create more mid range where as if you switch them out for all short stacks you get more top end.. of course this is allmotor so i dont know how it would apply to boost exactly..
Originally Posted by 4G63DSM
NOt to nit-pick or anything, but actually having 2 different lengths of runners on the motor can help broaden the effect of the helmholtz effect... Suzuki has great luck with this on the GSXR engines, where the center two runner are nearly an inch and a half longer than the outer two... It does lessen the effect at a specific rpm, but it will spread out that range it does effect...
IIRC the gsxr750 's two lengths were tuned for 9700 rpms and 10,300..... ( i think)
with the bike theory in mind its also fed from the center and not the side of the airbox and the 2 taller stacks in the center create more mid range where as if you switch them out for all short stacks you get more top end.. of course this is allmotor so i dont know how it would apply to boost exactly..
Like I stated before, boost kinda blankets a poorly designed manifold. I personally feel that is why so many companies produce manifolds for Forced induction applications, and not that many make them for NA.
Good luck on your testing guys!
Jan 11, 2008, 10:17 AM
#324
Account Disabled
Join Date: Nov 2006
Location: Akron, Ohio
Posts: 174
Likes: 0
Received 0 Likes
on
0 Posts
Jan 11, 2008, 11:22 AM
#326
Evolving Member
Join Date: Mar 2007
Location: In front of a Catia screen
Posts: 272
Likes: 0
Received 0 Likes
on
0 Posts
Your not really nitpicking, just stating what some companies have done. I have worked a lot with very high RPM bike engines, and have built custom EFI systems and manifolds for them. I am very familiar with the original configurations of the stock air boxes and manifolds. While it can deffinatly broaden the effect, it also requires a much more complex control of fueling, and individual cylinder triming because 2 cylinders are not getting the "extra boost" that the other 2 cylinders are getting at the same time. With the way the stock configurations are designed, it promotes equal flow amoungst all the cylinders, and does "broaden" the effect a bit, but you also have to remember that those engine can rev high enough to make use of the harmonic pressure pulses for the different lengths.
Like I stated before, boost kinda blankets a poorly designed manifold. I personally feel that is why so many companies produce manifolds for Forced induction applications, and not that many make them for NA.
Good luck on your testing guys!
Like I stated before, boost kinda blankets a poorly designed manifold. I personally feel that is why so many companies produce manifolds for Forced induction applications, and not that many make them for NA.
Good luck on your testing guys!
By the way,, the helmholtz doesn't apply to just high rpm engines.. in the late 50's and early 60's chrysler had used this in there v-8's wedge motors... (real low rpm tuned runners, and yes, they were feakishly long! the carbs hung off the opposite bank while the runners criss crossed... thus the name cross ram..)
If i recall correctly chevy's 69 Z-28 camaro with the trans-am spec 302 also did this
way back in the day... and now, I don't believe any modern auto manufacturer today doesn't do this, regardless of the model..
But I'm not try to argue, i agree that boost can mask some design flaws in an intake, but not eleminate them completely. Sometimes it can magnify the differences. beyond a few simple hand calculations to determine optimum runner length for a given rpm there are terrific software programs out there that can take this a step further, Ricardo wave and GT power are two off the top of my head.....
Jan 11, 2008, 11:26 AM
#327
Evolving Member
Join Date: Mar 2007
Location: In front of a Catia screen
Posts: 272
Likes: 0
Received 0 Likes
on
0 Posts
you guys want ot see a funky intake manifold that looks like a squid.. .check an old E-30 bmw with the straight 6.... (325i)
Jan 11, 2008, 11:35 AM
#328
In 1968, I had a 413 manifold that came in 2 pieces, one for each bank. The manifold crossed over from left bank, over the right bank valve covers and dropped down, where the carburetor mounted. I'm sure that's the one you're talking about. Twin carbs with each runner being at least 30 inches long. Sorry, back On Topic.
Jan 11, 2008, 11:39 AM
#329
Evolving Member
Join Date: Mar 2007
Location: In front of a Catia screen
Posts: 272
Likes: 0
Received 0 Likes
on
0 Posts
In 1968, I had a 413 manifold that came in 2 pieces, one for each bank. The manifold crossed over from left bank, over the right bank valve covers and dropped down, where the carburetor mounted. I'm sure that's the one you're talking about. Twin carbs with each runner being at least 30 inches long. Sorry, back On Topic.
its MOPAR or no car!!!