On our cars the runners connect to a single plenum with a single throttle body, it has two ports on the throttle body but it dumps air into a single plenum and distributed down the ports. I was trying to do research on the Viper intake manifold I am having a hard time finding detailed technical info about the intake. But it seems to have 2 independent plenums with 2 single throttle body’s, with the runners crossing across the motor to the opposite banks. This seems to be a great idea; you still have a long enough runner length to build substantial lo range power but not long as to kill upper end power. Also the Ferrari seems to also use a dual plenum for the same reason, but on newer Ferrari motors they have dual runners, one small and one large that opens with a butterfly at higher rpm’s to help with breathing up high. My question is would a dual plenum design work on a 350-383 V8, or does it only work correctly on v10(viper) or v12 (Ferrari) motor I am not very good at understanding the pressure wave pulses that effect the way the manifold works, and am sure they are different on a v10 or v12..

 

while I can't really answer your question or give you any technical info.. my 2000 Maxima with a V6 uses a dual runner type set up and a butterfly valve to switch to the short runners over i think 5500 rpm. So I would think it could be used on a V8 also.

 

that is what i am thinking i have seen this type of intake on a lot of cars lateley but not on a v8.

 

Scribbles,

I've been thinking about this too. The idea is to keep the tuned runners which allow for enormous torque but in some cases they are shortening the length of the runners (like First injection's system) or providing another larger runner to act like a secondary, if you will, that would open up the top end breathing.

This makes sense but this is technology that is applied to new motors of which the cost of the r&d, design and implementation is incurred in the higher price of the vehicle. Now the application can be on v6's like Jay said or v8 v10 v12 or what have you, the idea is the same. It is the further advancement of a tune port style intake and, like the lt1 mani was fitted to our l98 s either by the great work of Scott at Lt1 intake .com or by the exponentially more expensive mini ram, it is demand that will cause this type of manifold to become available for our l98s. It is a really efficient design much similar to double pump carbs in the sense of having a smaller jet or runner for normal driving and under hard acceleration the larger jets kick in or in this case it would be the larger runners.

Maybe one day they will start making the ls1 intakes for our cars or retrofitting them to fit. Its just going to add another part for all of us to keep saving for ! There is always something new !!

Rabi C.

 

yep very good concept to have. C5-R and i believe C6-R lsx racing motors use dual split plenum design. not only does it look awesome, it apparently makes good power everywhere.

id like to look into a superram style intake, but instead of one large plenum... just cut it in half and make two singles... then put some kind of cover inbetween to tie it all together. would look great in my opinion

 

Off the top of my head, I think the LT5 intake did this. I also don't think it's really a new concept, as I seem to recall some early muscle car era vehicles experimenting with things like this. But I can't remember exactly.

Dave

 

It dosent seem like a new idea, the cross fire( i think that is right) intake on the earley v8 third gens was a idea kinda like this it just didint work verry well, Just trying to figer out if any intakes could be modifies to work well with a l98 My main idea would be to fabricate a intake much like the Gen1 and Gen2, vipers. Just 2 tubes like 3" with runners crossing to the opisite banks.



sorry bout the shitty pic, i only have paint. how would that screw up the harmonics? any idea?

 

Also just did some research on the lt5. That is a crazy *** motor. It had in efect 2 intake paths, one small and one big. under 1/2 throtle and less than 3500rmp, it runs througe a small set of valves and 1 TB, and above that it opens a second set of tb than run through a second set of larger valves with there own intake path, into the head. It seems the point being more about fuel econemy and epa standerds than hp from what i was reading. buy way complicated. 4 valves per head, dohc, and 3 TB's

 

fuel economy and power aren't unrelated. if you've tuned your car, you know that in a steady state of tuning where you're working on partial throttle you go for the least tps, or the least throttle you can run at a particular load and rpm, all you are doing is increasing efficiency which is at the basis of both performance and economy. the problem with that is on some super performance motors that can flow rediculous air, you lose your air velocity, the motor is efficent enough, the intake and tb and such are just too big. in comes the concept of multiple intake paths/valves, at low load and rpm, you have enough air velocity to get great efficiency and response (good atomization, good cylinder fill, etc) and on the high end you have terrific air volume from the combined runners total flow. this is where the automotive industry has been focused for the last 15 years, notice alott of import cars now run variable valve timing, vtec, and so on. this accomplishes giving the motor flexibility for both power and economy by keeping it in a good efficiency range no matter what the situation. variable valve timing is a cheaper solution that is keeping older motors competitive, but in the next 20 yrs you'll see it become normal. just like efi was a huge step forward, variable valves and intake paths are the next step. as far as dual intakes, the earliest i know of is chrsler's crossram for the max wedge cars. without port fuel injection the system is very troublesome, as evidenced by the CFI injection that evolved into TPI.

 

on a quick sidenote, you'll notice that the domestic manufacturers motors have stayed away from variable valves. the hemi's are now running multiple displacement motors, in my opinion this is because the japanese beat us to the punch and we're scrabbling to keep our fuel efficiency numbers competitive since its become such an important part of buying a new car. the pushrod v8 is not a great setup for putting variable valve timing into at all and that's all the big three have worked with for the last 50 years as far as performance goes. the LS series is keeping the small block alive but it's on its last leg in my opinion. its main strengths have been maximized(small size, lightweight, huge comparitive displacement to competing motors), economy is the big thing now,,

 

It always amazes me the wealth of information on this site, thanks for all the great info so far.

 

i just read somebody said a 3 inch runner for each cylinder? uhhhhhmmm,,that'd be an interesting project, try idling on a plenum of that size, if you have a dual 3 inch exhaust, so say one 3 inch exhaust to serve each bank, which is overkill, then you'd need some insane heads to be able to use a 3 inch i.d. runner to feed a 4 inch bore cylinder, i'de like to see that for s and g's

 

YOu think they meant 3" in length? Probably not 3" in diameter.

 

3 inch diameter was my interperetation, 3 inch length would have insufficient plenum volume i think, and wouldnt clear the pther bank if the crossed.

 

Sorry what I meant was dual 3" tubes for a plenum, with 1 5/8 to 1 3/4 tubes for runners. Running across each other. That seems to be similar to what the early vipers were running. With a runner length bout 2/3 what it is on a standard tpi. Like 7-8 inches. (I think tpi is 12-13, but am probably wrong) keep some runner length so you still have the down low power, but let it breath up to 6,500 - 6,800rpm or so. I was thinking in my head and not explaining what I was thinking very well. I am not sure about what isolating the left bank from the right bank would do to the intake pulses in the manifold though.

 

Although I don't recall the engine model number, there was a 16 runner plenum Corvette motor produced for a short period. It had one primary runner per cylinder always open and one more with a butterflyers that opened with increased demand. It kept a high velocity charge in pay at low rpm and added needed ait to the upper rpm's where the single small runners would choke. Snakey looking as all hell! Now it's rare, and veryexpensive. The newer engines outproduce it at less cost and less parts. A jaw dropping sight though for any motor head! Made around 1992-1994 if I recall properly.

edit: i remembered, the ZR1

 

lt5 had 16 runners.

 

the lt5 vettes one holds alot of records for longevity and constant speed. a little over 170 mph in a 24 hour span.

 

A couple of weeks ago there were custom made intake at ebay.
A guy ahve welded two upper intakes from a TPI, connected them with little runners, and made runners from both sides fit lower TPI intake. They had two TB's. Probably overkill but looked.. hmm.. wanted to say great.. but it was strange