Author Topic: Basic intake designs  (Read 11245 times)

Online Chryco Psycho

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Basic intake designs
« on: March 16, 2005 - 08:59:25 pm »
intakes
 Lets take a look at intake manifolds
 there are various designs & reasons for the designs to be used
 as with cams this is one area where often the wrong intake is used for an application
 there are 3 basic designs of intakes ,
- dual plane intakes
- single plane intakes
- tunnel ram intakes
 Intakes are made from Cast Iron or Aluminum , the factory has used both , the aftermarket
 uses alum virtually exclusively

 Any intake used Must be matched to the Cam so both work at the same RPM , having a cam that works at
 very high rpm matched with an intake that works at low rpm will give extremely disappointing results
by the time the cam starts to work the intake is restrictive , it is the same problem if you reverse
the situation  witha cam that works at low rpm & an intake that works at high rpm the 2 will not make
power at the same time & the results will be disappointing
 
The Dual plane is designed to get good throttle response at low rpm divides the carb in 1/2 so 1/2 of the
engines cylinders use 1 side of the carb . Thuis is done to reduce the amount of air that needs to be
moved when the cylinder starts to pull the air in so with 1/2 the volume of air to move it is easier
 to get it moving & helps to more completely fill the cylinder at low RPM , this also increases
 signal at the carb & allows the carb to react more quickly giving better response fuel
atomization which can also increase gas milage , the down side is at hiher rpm the carb seems
smaller& will limit high rpm power , aslo the entracne into the heads is different for the
upper & lower plane so flow into the heads is not as even. To make power at higher rpm with a
dual plane  you must increase the common plenum area under the carb & use a bigger carb
to get enough flow , the 6 pack is awesome at this , the plenum is large as it goes under
all 3 carbs & you have 1/2 of approx 900 cfm for only 4 cylinders to draw from , in tests
 the   6 pack has proven to be as good a most of the best single plane intakes & carb
combos aavailble today , it big drawback is the cost at more than 2x the cost of the best
single 4 bbl carb & intake packages available
 The Best dual plane intake is the Performer RPM but hood clearance can be an issue the ther
decent intake is the old CH4B 

the single plane is the most versatile intake. by changing the runner shape & size & more
importantly the plenum volume a single plane can be made to work at virtually any rpm
By making the runner smaller & decreasing the volume of the plenum a single plane can make
power in the same low rpm range as the dual plane & usually with a smaller carb as well
which again will increase signal at the carb , the advantage is at higher rpm any single
cyl can draw from all the venturis in th ecarb instead of just 1/2 meaning you can have
the same responsiveness @ low rpm without the choking effect at higher rpm . conversely
as plenum size is increased & the runner volume is increased signal is lost at the carb ,
more air volume has to moved to fill the cyl & low rpm response is lost but at higher
 Rpm breathing is dramatically improved as the time to fill the cylinder is shortened
so the more air close to the valve the bette. To illustrate this better at ilde the
intake valve opens around 6 x / second , whereas at 7200 rpm [yes this is possible I
shifted my 440  Duster there for 9 Years] the valve opens 60 x / second!!
 The best intakes make the turn early into the head & have a straight run at the port
into the cyl head this helps to equalize distribution into each cylinder, Like the M1
 Holley Street Dom & Victor , poorer intakes are the Torker series & Team G which make
a sharp turn right at the head which causes a lot of turbulence & the cylinder filling
is uneven
 For good results at lower RPM the Street Dom is best & the torker [original not torker 2]
work well The Street Dom also is good for higher RPM & averages the best power over all rpm
range , for Higher RPM the M1` & Victor are the best Large single planes

  The tunnel ram comes in many forms , the whole  purpose is tuning the pulse waves inside
intake , as the intake valve closes it sends the shock wave back into the intake & will
bounce back towards the valve , ideally this shock wave / pulse needs to arrive back at the
valve as the valve opens again to provide a passive supercharging effect at high rpm ,
The first use was the long rams in the early 60s 413s at approx 26" long & tuned to work at
approx 3200 rpm for peak power at 70 MPH for cruising a passing on the highway , the shorter
 the intake runner the higher the rpm the effect works at , the Slant 6 had the Hyper pack
intake with a 4bbl carb which is a tunnel ram , the Hemi had 3 tunnel rams , the Rat Roaster
, the Super Stock cross ram & the Nascar Bath tub intake which are all cross rams similar to
the long ram 300 intakes but with much shorter runners to work at higher rpm. The newer
engines like the 94 & up Magnums use the long tunnel ram intkaes with curved runners ,
commonly know as the barrel intakes as with the single plane intakes runner size & length &
plenum volume dictate the rpm range where intake works best at. There are also the
aftermarket race tunnel rams with very tall vertical runners & different tops for single
4 bbl with a relatively large plenum , or 2 4 bbls & plenum or IR applications where 2 4 bbls
are used & there is no plenum at all & each runner is mated to 1 bbl of a carb so each
cylinder can be individually tuned
 essentially there are no good or bad intakes as each intake is specifically designed to work
in a given application with speicific cams & carbs 

Hot tip ... seing as most of these cars are not driven in the cold anymore using an intake
gasket that blocks the heat crossover port can be a big advantage on warm days
 Part # 1214 for B engines & 1215 for RB , From Fel Pro

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Offline heminut

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Re: Basic intake designs
« Reply #1 on: March 16, 2005 - 11:14:47 pm »
Excellent writeup Chryco! I'm sure a lot of folks on this board will benefit from it, thank you for taking the time to do it. :thumbs:
1970 5.7 Hemi Cuda

Online Chryco Psycho

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Re: Basic intake designs
« Reply #2 on: March 17, 2005 - 12:19:35 am »
glad to help , I will try to get some pix to go with it

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Offline mrbill426

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Re: Basic intake designs
« Reply #3 on: February 26, 2007 - 09:10:27 am »
Great info!  But.... where are the pics??  ;D

Are you suggesting then that a CH4B intake would be a poor choice for a (competitive) street/strip car?


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Offline vinb

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Re: Basic intake designs
« Reply #4 on: February 26, 2007 - 05:40:27 pm »
CP , is that CH4B the same as the old LD340? I am using a Weiand 8007 with a 3/4" spacer & a T-Q...

Offline mrbill426

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Re: Basic intake designs
« Reply #5 on: February 26, 2007 - 07:53:26 pm »
CP , is that CH4B the same as the old LD340? I am using a Weiand 8007 with a 3/4" spacer & a T-Q...


I have one of those...  It of course is for a small block, where the CH4B is an RB manifold.   Although I have not used it yet I am told it is similar in added performance over the best factory performance dual plane manifolds.  :2thumbs:

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'72 Sebring; bracket project
'64 Imperial Crown black on black
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Online Chryco Psycho

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Re: Basic intake designs
« Reply #6 on: February 26, 2007 - 11:23:57 pm »
The CH4B is supposed to perform very well in the rpm range it was designed for & will beat the factory dual plane intakes
the LD340 was a similar design for the small block engines

I need to get pix up

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Offline mrbill426

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Re: Basic intake designs
« Reply #7 on: February 27, 2007 - 12:03:03 am »
Yes, photos would be nice  :picture:

Is the CH4B a good choice for a more strip than street car, or would a street dominator be better?  The car is a, dare I say it, B Body automatic.   :bigshades: 
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'72 Sebring; bracket project
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Online Chryco Psycho

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Re: Basic intake designs
« Reply #8 on: February 27, 2007 - 10:32:50 am »
If you have a stall converter in the 2200 rpm range I would use the street dom , if the stall is less or thee powerband is limited to under 5500 you may see some benefit to the CH4B, if you have the hood clearance the Performer RPM would probably out perform the CH4b though   

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Offline mrbill426

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Re: Basic intake designs
« Reply #9 on: February 27, 2007 - 05:49:10 pm »
Thanks.
Actually I don't know what the stall will be :dunno: , this car is still on the drawing board.  It's a '72 Satellite 2dr HT that was a 318 car but will have a 440 from a '66 Imperial and a 727 from I think a '67 Satellite.  Since it will be more strip than street I am leaning towards a solid cam.   I suspect the power range will be in the 1500-6000 rpm range.  It has a pretty flat hood that I don't intend to punch any holes in; at least not right away.  It has an 8 3/4" rear end but the wierd thing is that it is a '742 case which I thought were phased out way before '72  :clueless:  Near as I can tell this car is all original; a real basic 318 grocery hauler, built in Aug '71.

About the 727, will the numbers on the pan rail tell me anything useful about it?

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'72 Sebring; bracket project
'64 Imperial Crown black on black
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Offline pink panther

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Re: Basic intake designs
« Reply #10 on: February 27, 2007 - 06:27:09 pm »
great stuff Chryco, you ought to post something every month to help educate us. Call it Chryco's world or something.
Scott   -  Member since 9/18/2005

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Re: Basic intake designs
« Reply #11 on: February 27, 2007 - 11:42:50 pm »
the #S on the tranny will tell you what application it was for Like HD or Police pkg etc 
I would guess the 742 was swapped at some point

Actually I write for the local Mopar club newsletter & generally post the same article here every second month
I am running out of topics though so if you have any suggestion on what to write about let me know 

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Offline mrbill426

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Re: Basic intake designs
« Reply #12 on: February 28, 2007 - 12:13:28 am »
the #S on the tranny will tell you what application it was for Like HD or Police pkg etc 
I would guess the 742 was swapped at some point

Probably right about the carrier, hopefully it is also a suregrip  :bananasmi , I have not checked it yet.

The numbers on the transmission pan rail are  H2801543      3279277  Nothing else seen  It has LARGE numbers on the converter housing of 2615
MOPAR or NO car!

'72 'Cuda 340, white on white
'72 Sebring; bracket project
'64 Imperial Crown black on black
'66 Imperial Crown; parts car

Online Chryco Psycho

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Re: Basic intake designs
« Reply #13 on: February 28, 2007 - 12:32:28 am »
Unfortunatly I have no reference to look up the tranny #S , Barry should though

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Offline Aussie Challenger

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Re: Basic intake designs
« Reply #14 on: March 12, 2007 - 04:03:24 am »
 :cooldancing: Yes Chryco this is a worthwhile thread, especially to me as I am still trying to make up my mind on what type of dual plane maniflod to buy. I have been leaning towards the Weiand 8007 over the Performer RPM, which would you recommend for a street only 360 4spd manual, '70 Challenger, Q'Jet or Thermoquad, 308 heads, cam in the 800 to 5500 rpm range with 3.23 rear.  :burnout: :woohoo:
Dave