- :
- 02' Protege ES (Gone)
16' Mazda 6 sport manual
well thats the million dollar quesiton
installed single runner intake manifold on my mp5!
- Thread starter jamesk
- Start date
well thats the million dollar quesiton
THEMAN- yea i get what your saying. the jdm cam works better for the stock manifold to the 626 manifold. that cam is made for a crappier manifold.
first of all, i dont have a jdm cam, so where the hell did that come from?
second of all, regardless of what you say, the stock mani's give the car too much turbulance and not much cfm rate and holds these engines back greatly. the 626 manifold is a freeflowing manifold, so obviously your low end wont improve.
third, you said the the jdm cam improves the flow rate on the stock manifold? so what, there is still room for much more improvement. the jdm cam needs much more improvement. your making it sound like its the best solution for our cars. no way, ken is comming out with much better cams soon that will blow the j-spec cams out of the water. maybe the jdm cam is the best solution for the stock manifold, but deff. not over all.
in conclusion, your limit is not our limit, so do not say you have the best flowing set up.
first of all, i dont have a jdm cam, so where the hell did that come from?
second of all, regardless of what you say, the stock mani's give the car too much turbulance and not much cfm rate and holds these engines back greatly. the 626 manifold is a freeflowing manifold, so obviously your low end wont improve.
third, you said the the jdm cam improves the flow rate on the stock manifold? so what, there is still room for much more improvement. the jdm cam needs much more improvement. your making it sound like its the best solution for our cars. no way, ken is comming out with much better cams soon that will blow the j-spec cams out of the water. maybe the jdm cam is the best solution for the stock manifold, but deff. not over all.
in conclusion, your limit is not our limit, so do not say you have the best flowing set up.
boy are you full of assumptions!
ok drop this stupid arguement. here are the pictures. ill explain each one.
here is what it looks like in the car
here is the vics and vtcs plug harnesses. leave them plug into the harnesses so you do not get a check engine light.
this picture shows the harness connected to the fuel rail. this harness is just moved over. the bracket does not line up, so you can see i only put one screw in rather than 2.
this is another view.
this is the t-tap i was talking about. you have to t into the vacuum line that goes from the sensor located in the top left corner of the car to the bottom of the intake manifold vacuum nipple. the other side of the t-tap is the end of the cruise control vacuum line.
that is where the old vacuum line from the cruise control unit use to go. the 626 manifold does not have that.
far view
here is what it looks like in the car
here is the vics and vtcs plug harnesses. leave them plug into the harnesses so you do not get a check engine light.
this picture shows the harness connected to the fuel rail. this harness is just moved over. the bracket does not line up, so you can see i only put one screw in rather than 2.
this is another view.
this is the t-tap i was talking about. you have to t into the vacuum line that goes from the sensor located in the top left corner of the car to the bottom of the intake manifold vacuum nipple. the other side of the t-tap is the end of the cruise control vacuum line.
that is where the old vacuum line from the cruise control unit use to go. the 626 manifold does not have that.
far view
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I haven't read through all the brouhaha in this thread... but there are some very common missconceptions coming through.
for starters - the P5 manifold is not duel runner to improve top end response, its duel runner to fatten up the curve. Runner length determines (especially on an NA car) WHERE peak power is going to occur. It wont determine WHAT peak power you are going to get - that is down to runner volume, velocity and flow. The length, however, will impact where in the rev range maximum power (assuming everything else is right, i.e. the manifold will flow a desired amount at that RPM) is going to happen.
To state that the P5 manifold is in anyway a superior part for performance vs the 626 manifold is a demonstration in not knowing what you are on about.
Duel runner manifolds (of which the P5 manifold isn't a "true" example of - it more or less fakes it by increasing runner volume via a large chamber) is a compromise. You compromise flow. Without flowing a required volume of air, you don't make power, its as simple as that.
Flow bench numbers i've seen on the P5 manifold vs the 626 manifold would indicate that the 626 manifold is a superior manifold by design - why it was on the 626 and not the P5, I'm not in a position to say.
Oh - and the P5 manifold does not utilize helmholtz resonance to benefit power as has been incorrectly inferred in some posts. If you have the formulas for calculating an ideal 3rd of 4th order resonance manifold for the P5, then compare it to the dimensions of the standard manifold you would see plain and simply that it is nowhere near correct.
Put in its simplest terms, if the 626 is a beneficial modification. Sure you get the most out of it when you are turbo charged, but gains HAVE been seen on the NA motor. Its an NA manifold FFS....and its a vastly superior manifold to the standard P5 manifold. Is it perfect? hell no... if it was perfect i wouldn't bother making my own manifold - but it is certainly better from a performance perspective than the standard manifold.
It may not be superior from a *technical* standpoint, but often simplicity is best... a tunnel ram manifold is probably the simplest manifold you could design - but they are still the favoured manifold for performance engines - why? because they just work.....
The same goes for the 626 manifold....
edit: OBVIOUSLY with a change like this, an ecu would be helpful.... not sure how the standard ecu would go with a manifold change, especially to something which will theoretically flow more air - it should adapt, but you wont get the most out of it....
Oh and - my comments are "assumptions".....i've never actually installed a 626 manifold on a P5... i'm just going purely off the engineering papers i've got here, and the 60+ hours of research into the subject I put in prior to designing a custom mani for my car.... 60+ hours research including speaking to many people who have years of experience in the field, reading loads of physics and engineering papers and so forth... if you want any clarification on how this stuff works, by all means, give me a yell.
this manifold would certainly make bottom end feel a lot more lathargic...without the "duel runner" setup, the power curve will be considerably narrowed....and given the runner lengths would be leaning more towards midrange/top end power....so you may feel like the car isn't pulling as hard off the line..... but on a dyno i wouldn't be surprised to see a steady gain once you are up in the midrange to top end of the rev range...
for starters - the P5 manifold is not duel runner to improve top end response, its duel runner to fatten up the curve. Runner length determines (especially on an NA car) WHERE peak power is going to occur. It wont determine WHAT peak power you are going to get - that is down to runner volume, velocity and flow. The length, however, will impact where in the rev range maximum power (assuming everything else is right, i.e. the manifold will flow a desired amount at that RPM) is going to happen.
To state that the P5 manifold is in anyway a superior part for performance vs the 626 manifold is a demonstration in not knowing what you are on about.
Duel runner manifolds (of which the P5 manifold isn't a "true" example of - it more or less fakes it by increasing runner volume via a large chamber) is a compromise. You compromise flow. Without flowing a required volume of air, you don't make power, its as simple as that.
Flow bench numbers i've seen on the P5 manifold vs the 626 manifold would indicate that the 626 manifold is a superior manifold by design - why it was on the 626 and not the P5, I'm not in a position to say.
Oh - and the P5 manifold does not utilize helmholtz resonance to benefit power as has been incorrectly inferred in some posts. If you have the formulas for calculating an ideal 3rd of 4th order resonance manifold for the P5, then compare it to the dimensions of the standard manifold you would see plain and simply that it is nowhere near correct.
Put in its simplest terms, if the 626 is a beneficial modification. Sure you get the most out of it when you are turbo charged, but gains HAVE been seen on the NA motor. Its an NA manifold FFS....and its a vastly superior manifold to the standard P5 manifold. Is it perfect? hell no... if it was perfect i wouldn't bother making my own manifold - but it is certainly better from a performance perspective than the standard manifold.
It may not be superior from a *technical* standpoint, but often simplicity is best... a tunnel ram manifold is probably the simplest manifold you could design - but they are still the favoured manifold for performance engines - why? because they just work.....
The same goes for the 626 manifold....
edit: OBVIOUSLY with a change like this, an ecu would be helpful.... not sure how the standard ecu would go with a manifold change, especially to something which will theoretically flow more air - it should adapt, but you wont get the most out of it....
Oh and - my comments are "assumptions".....i've never actually installed a 626 manifold on a P5... i'm just going purely off the engineering papers i've got here, and the 60+ hours of research into the subject I put in prior to designing a custom mani for my car.... 60+ hours research including speaking to many people who have years of experience in the field, reading loads of physics and engineering papers and so forth... if you want any clarification on how this stuff works, by all means, give me a yell.
this manifold would certainly make bottom end feel a lot more lathargic...without the "duel runner" setup, the power curve will be considerably narrowed....and given the runner lengths would be leaning more towards midrange/top end power....so you may feel like the car isn't pulling as hard off the line..... but on a dyno i wouldn't be surprised to see a steady gain once you are up in the midrange to top end of the rev range...
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Another post (sorry) regarding the effect of intake cams on optimum runner length.
For this experiment, we'll use a fantasy engine, with 2 distinct fantasy intake cams, and calculate the optimum runner length for 1st order resonance (the strongest) - 1st order resonance is largely impossible to achieve in our cars, as you'll see by the runner lengths that are spat out - but its the easiest to calculate. Everything else will be assumed to be exactly the same....
First a bit of a primer about what happens....
Air is being pulled into the plennum on every single intake stroke - that air is then rushing down every single runner at, in an ideal situation, the same rate. The amount of air is not important for this calculation, but is important when it comes to designing a manifold for your car (essentially you want to achieve the maximum CFM of air at the highest possible velocity in the runners).
In the case of a valve being closed on any one of the ports (which in a 4cyl motor will occur 3 out of 4 times per complete cycle), a sound wave will travel back up the intake runner (at the speed of sound, obviously). When it reaches the other end of the runner, a sound wave will be reflected back down the runner towards the valve. The object is to tune your runners so that the sound wave reaches a valve when it is open.
1st order resonance occurs when the air makes this trip once before meeting an open valve
2nd order it makes the trip twice (down to closed valve, up to the air horn/velocity stack, down to a closed valve, up to the air horn velocity stack, and back again, meeting an open valve)
and so on and so forth up to as many orders of resonance as you care to count.
With each trip, the strength of this sound pressure wave decreases.
Working out how long a runner needs to be is done using the following formula:
L = ((EVCD x 0.25 x V x 2) / (rpm x RV)) - (D x 0.5)
Where
L is the length of the runner
EVCD is effective valve closed duration
rpm is the desired rpm you want the event to occur at.
RV is the reflective value
V is the pressure wave speed
D is runner diameter.
To calculate the EVCD we use this formula:
EVCD = 720 - (D - 30)
where EVCD is effective valve closed duration, D is the cam duration.
subtracting 30 from the duration is a correction factor, essentially timing the event to occur 30 degrees after the valve opens (air cannot pass through a closed valve).
so, now we've got that sorted.... lets talk about our fantasy manifolds and cams etc.
for arguments sake, we want RV 1 to occur at 6500 rpm in both cases. In both cases we will be using 1.5in inside diameter pipes for our runners.
setup A we will run an intake cam with a duration of 250 degrees (leaving us with an EVCD of 500 degrees)
setup B we will run an intake cam with a duration of 310 degrees. (leaving us with an EVCD of 440 degrees).
We will assume a pressure wave speed of 1300 feet per second in both cases
in order to get reflection 1 occuring at 6500rpm, the setups each require a runner length of:
Setup A 49.25inches
Setup B 43.25inches
resonance 2, 3, 4, 5, 6 ... ad infinitum will occur at ever decreasing points in the rev range..(you can play around in an excel spreadsheet to see exactly where these "kicks" will occur...).
So, what happens if we build the intake manifold for setup A, but put the cam from setup B in the engine...
I'll crack out my trusty excel spreadsheet, and do a bit of goal seeking..........
The result would be 1st order resonance occuring at 5721rpm (or there abouts)....
So, an increase in intake cam duration of 60 degrees, results in moving the power DOWN by a total of roughly 700 rpm.
Ok enough fantasy engines... lets see what the effect on length is with "real" engines... i'll compare the FSDE USDM spec intake cam with the FSDE JDM spec intake cam:
(taken from TheMAN's protege FAQ).
USDM EVCD = 520 degrees
JDM EVCD = 509 degrees
Optimal runner length for 1st order to occur at 6500 rpm
USDM = 51.25in
JDM = 50.15in
JDM intake cam in motor with theoretically optimal intake manifold for USDM cam will have 1st order resonance occuring at roughly 6363 rpm...
basically, the JDM intake cam makes next to no difference with regards to this theoretically perfect manifold - therefore it will make next to no difference in the real world "imperfect but better than the stock P5" manifold.....
(this illustration is purely from the point of view of calculating optimum intake manifold runner lengths.... i'm not saying that the JDM cam isn't better than the USDM cam - just pointing out that it is a flawed argument to claim that the JDM cam is designed to work with the crappier manifold, or visa versa)
Incidently, if you build the formula in a spreadsheet, then measure the runner lengths of the 626 manifold (or any single runner manifold for that matter), it should be fairly easy to calculate at what RPM each reflection will occur.....
* calculations taken from a paper entitled "Induction Systems" - http://www.grapeaperacing.com/GrapeApeRacing/tech/inductionsystems.pdf
For this experiment, we'll use a fantasy engine, with 2 distinct fantasy intake cams, and calculate the optimum runner length for 1st order resonance (the strongest) - 1st order resonance is largely impossible to achieve in our cars, as you'll see by the runner lengths that are spat out - but its the easiest to calculate. Everything else will be assumed to be exactly the same....
First a bit of a primer about what happens....
Air is being pulled into the plennum on every single intake stroke - that air is then rushing down every single runner at, in an ideal situation, the same rate. The amount of air is not important for this calculation, but is important when it comes to designing a manifold for your car (essentially you want to achieve the maximum CFM of air at the highest possible velocity in the runners).
In the case of a valve being closed on any one of the ports (which in a 4cyl motor will occur 3 out of 4 times per complete cycle), a sound wave will travel back up the intake runner (at the speed of sound, obviously). When it reaches the other end of the runner, a sound wave will be reflected back down the runner towards the valve. The object is to tune your runners so that the sound wave reaches a valve when it is open.
1st order resonance occurs when the air makes this trip once before meeting an open valve
2nd order it makes the trip twice (down to closed valve, up to the air horn/velocity stack, down to a closed valve, up to the air horn velocity stack, and back again, meeting an open valve)
and so on and so forth up to as many orders of resonance as you care to count.
With each trip, the strength of this sound pressure wave decreases.
Working out how long a runner needs to be is done using the following formula:
L = ((EVCD x 0.25 x V x 2) / (rpm x RV)) - (D x 0.5)
Where
L is the length of the runner
EVCD is effective valve closed duration
rpm is the desired rpm you want the event to occur at.
RV is the reflective value
V is the pressure wave speed
D is runner diameter.
To calculate the EVCD we use this formula:
EVCD = 720 - (D - 30)
where EVCD is effective valve closed duration, D is the cam duration.
subtracting 30 from the duration is a correction factor, essentially timing the event to occur 30 degrees after the valve opens (air cannot pass through a closed valve).
so, now we've got that sorted.... lets talk about our fantasy manifolds and cams etc.
for arguments sake, we want RV 1 to occur at 6500 rpm in both cases. In both cases we will be using 1.5in inside diameter pipes for our runners.
setup A we will run an intake cam with a duration of 250 degrees (leaving us with an EVCD of 500 degrees)
setup B we will run an intake cam with a duration of 310 degrees. (leaving us with an EVCD of 440 degrees).
We will assume a pressure wave speed of 1300 feet per second in both cases
in order to get reflection 1 occuring at 6500rpm, the setups each require a runner length of:
Setup A 49.25inches
Setup B 43.25inches
resonance 2, 3, 4, 5, 6 ... ad infinitum will occur at ever decreasing points in the rev range..(you can play around in an excel spreadsheet to see exactly where these "kicks" will occur...).
So, what happens if we build the intake manifold for setup A, but put the cam from setup B in the engine...
I'll crack out my trusty excel spreadsheet, and do a bit of goal seeking..........
The result would be 1st order resonance occuring at 5721rpm (or there abouts)....
So, an increase in intake cam duration of 60 degrees, results in moving the power DOWN by a total of roughly 700 rpm.
Ok enough fantasy engines... lets see what the effect on length is with "real" engines... i'll compare the FSDE USDM spec intake cam with the FSDE JDM spec intake cam:
(taken from TheMAN's protege FAQ).
USDM EVCD = 520 degrees
JDM EVCD = 509 degrees
Optimal runner length for 1st order to occur at 6500 rpm
USDM = 51.25in
JDM = 50.15in
JDM intake cam in motor with theoretically optimal intake manifold for USDM cam will have 1st order resonance occuring at roughly 6363 rpm...
basically, the JDM intake cam makes next to no difference with regards to this theoretically perfect manifold - therefore it will make next to no difference in the real world "imperfect but better than the stock P5" manifold.....
(this illustration is purely from the point of view of calculating optimum intake manifold runner lengths.... i'm not saying that the JDM cam isn't better than the USDM cam - just pointing out that it is a flawed argument to claim that the JDM cam is designed to work with the crappier manifold, or visa versa)
Incidently, if you build the formula in a spreadsheet, then measure the runner lengths of the 626 manifold (or any single runner manifold for that matter), it should be fairly easy to calculate at what RPM each reflection will occur.....
* calculations taken from a paper entitled "Induction Systems" - http://www.grapeaperacing.com/GrapeApeRacing/tech/inductionsystems.pdf
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thats all well and good - and your right....
purely from a theoretical point of view, it'll work though
- :
- 02' Protege ES (Gone)
16' Mazda 6 sport manual
and a few butt dynos
ok, so I maybe wrong in what I stated.... but explain what the function of the VICS is on our stock intakes? is it just an additional plenum chamber?
I still think our stock intakes utilize a watered down form of VRIS
here's some info on VRIS
http://www.mx6.com/forums/2g-faq-general/162593-faq-what-vris-everything-you-wanted-know-more.html
http://www.geocities.com/mikey9t6/car_uvwxyz_vris.htm
http://www.mazdamaniac.com/tech/SAE_20920677.htm
interesting
but I never did say the JDM intake cam was ideal, just that I feel is better matched for the VICS intake
It is a (rather poor) attempt at a faking duel runner system (by faking, i mean, there are not actually 2 distinct sets of runners, instead the runners length is made variable by the use of the VICS chamber, which in effect increases the volume of the runners when activated, giving a simillar effect to having 2 distinct runners), i'll give you that. The result is essentially a broadening of the power curve. A means of providing reasonable low end response without overly sacrificing top end power. However, the critical problem with the VICS chamber (or, it could be argued, the entire manifold design) is that it doesn't flow very well. The 626 manifold will (in theory at least, given the flow numbers - and also given anecdotal evidence from NA guys that have installed them) outperform the P5 manifold at simillar air velocities in the midrange to top end, because it, overall, has more capacity to flow.
It is true, that flow isn't everything in an NA motor, but it is critically important. Velocity without flow isn't worth anything - the object is to still attempt to pump as much air and fuel as possible
I'm not debating whether or not VICS works - i am simply pointing out that just because its got VICS, and is a technically superior/more complex manifold design does not mean it is better than the 626 manifold which is far more simplistic.
never said you claimed the JDM cam was ideal - i was simply pointing out that if it is a better match for the VICS intake, its not a better match by much - by using an extreme example of a perfect (that is, impossible to build with the space that we've got....theres no way you can fit 50+ inch pipe work behind our motors without some insanely convoluted pipe work) intake manifold, it shows that the difference in cam duration can, at best, affect the power curve by at best moving it a few hundred RPM in either direction. Neither manifold even approaches an ideal design, but the cam argument is not going to hold water from a purely intake manifold design point of view given only an 11 degree change in duration (obviously, the JDM cam with higher lift is going to allow more to flow, assuming the manifold which is upstream of the valves can supply the air). Far higher duration cams would obviously have a larger effect on an ideal runner length, as illustrated by the fantasy example.
I was also pointing out (purely for interests sake) what the actual affects of resonance are, and how to tune a manifold - or how to determine what a manifold is tuned to. Those calculations are essentially old school tunnel ram manifolds. 1st order resonance can create substantial positive pressure at the valve on a natrually aspirated motor (because the sound wave compresses the air in the runner) - 4psi at the valve on a properly designed manifold is not out of the question (see Nascars for examples) - really insane manifolds can achieve much higher 'boost' - assuming of course pressure drop in the runners doesn't become an issue.
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you're right in that OEM dual runner intake systems give a flatter powerband... IMO more useful for the street... far from ideal as far as maximum hp standpoint.... 99% of our cars are street driven, and I really think that this is more practical than to have the more "max power" intake
if you check out the integra GSR's B18C1 intake manifold, it is dual runner... but the B18C5 in the Type-R gets rid of that and have a single runner.... the differences? the GSR has a flatter powerband, whereas the Type-R is more peaky
as I said before, a single runner system can only be designed for a certain rpm range.... in the case of the 626 one, I believe it is more for midrange response... a compromise... the protege's VICS intake is a compromise for a flatter powerband, not designed for something peaky but it does give better top end IMO over the 626 one
oh and the JDM intake cam has the same lift, it just has more duration and provides more overlap
if you check out the integra GSR's B18C1 intake manifold, it is dual runner... but the B18C5 in the Type-R gets rid of that and have a single runner.... the differences? the GSR has a flatter powerband, whereas the Type-R is more peaky
as I said before, a single runner system can only be designed for a certain rpm range.... in the case of the 626 one, I believe it is more for midrange response... a compromise... the protege's VICS intake is a compromise for a flatter powerband, not designed for something peaky but it does give better top end IMO over the 626 one
oh and the JDM intake cam has the same lift, it just has more duration and provides more overlap
