CARBON INTAKE MANIFOLD

[heefner]

Why would you bother spending time and money to make a product that wold get you minimal gains at best.  Anybody with enough money to buy this product, and willing to, is not going to want to run the same crappy 2 injector system.  Why would they?... So they can say "i've got a CF intake" ???... Thats gay.  If you serious about making this then do it once and do it right. Go MPI and be done with it.  As for street or strip Most everyone on this site still drives their car on the street.  A good desing will perform well everywhere. If they are a dedicated hard core racer chances are they already have thier own setup.

[AustinTSI]

As it applies to turbo motors (not carbed motors), does anyone have any actual published info discussing the performance differences of various plenum sizes?

 

Put another way: if I made a intake manifold with 8" runners, what would be the perfomance difference of a small plenum to a large plenum.

 

For about the last 6 years I'v been thinking about a making a intake manifold that would allow you to adjust the plenum size though the use of spacers. The problem is that I can't find anything that discusses what the difference would be.

 

I mean how difficult would it be for a magazine (or someone else) to make two intakes, one with a large plenum and one with a small plenum, and then tune and test them on a dyno on the same turbo car.

 

Has anyone seen anything like this?

 

Dave.

[shift1313]

generally the plenum size (mathematically) changes with runner length.  The numbers say you want a certain volume compared to your engine displacement.  I dotn remember exactly but it might be 1:1.  Shorter runners are for high rpm cars. longer runners give you better torque numbers.  So if you look at EIP intake they have short runners and a huge plenum.  I think i ran the numbers at one time to get peak power in a good useable range for the stock powerband you need 30" of runner per cyl or something crazy so there is always going to be compromise because that much would be a nightmare.  I havent found any great resources online for turbo intakes for cars but there are plenty of books you can check out.

 

someone please correct me if i have messed any of the info up.

 

 

oh and heef and dc are right it is a waste to build tbi carbon intakes but i know alot of people have money and dont have the drive for mpi setups but i honestly dont see alot of these selling.  People arent lining up down the block to get the few mpi already avail at reasonable prices.  Magnas seem to be the best seller and they are under $200. thats a hard price to beat.

[Metric-man]

plenum

 

n 1: a meeting of a legislative body at which all members are present; "the plenum will vote on all tax increases" 2: an enclosed space in which the air pressure is higher than outside.

 

Although this isn't the best example...

 

 

 

It would be the simplest idea of just re-designing the OVC pipe into more of a "plenum" shape.

 

We have been conditioned to think of the throttle body inlet pipe as a (OVCP) OVC pipe.

Why not think of it as a plenum..?

[shift1313]

because its on the wrong side of the TB butterfly?  You are going to have a different pressure/vacuum on either side over varying conditions.  

[Metric-man]

Is the plenum designed for street use or race track use..?

 

Because for track use that would matter.. but at different varying speeds w/ partial throttle that is going to happen anyway.

 

If you want a true race plenum you would design it w/ throttle plates on each runner just for that reason.

[AustinTSI]

Funny you mention the throttle plates on each runner (individual throttle bodies - ITB) because that is what my intake will be based on. I am trying to find out what the difference would be between these two setups.

 

http://home.austin.rr.com/neozoe/CarStuff/tb_question.jpg

 

Here are some pics of what I have in mind.

 

http://home.austin.rr.com/neozoe/CarStuff/quad-butterflies.JPG

 

http://home.austin.rr.com/neozoe/CarStuff/intake2.jpg

 

 

I already have the manifold, the throttle bodies are standard DCOE but fuel injected. I'm just trying to decide what the runners and plenum will look like (and get the bucks together).

 

1. Either the EIP cannon style (short runners, large plenum)

2. Magna style (long runners, small plenum)

3. or something totally different

 

either way I will be useing ITB.

 

What I have really been trying to figure out is how to design an intake that would allow you to pick what runner length and plenum size you would like when you install it. Then, if you don't like the results, you could adjust it until you get something you do like. I've got the design in my head, I just haven't modeled it out yet.

 

I would really appreciate any info on the affects of ITB. Also, I would like to know everyones thoughts on my impression that the magna intake doesn't seem to be working out as well as everyone was hoping. I only say this because I believe (maybe I'm wrong) that there isn't one person that is getting 400+hp yet. IS there anyone developing 400+hp and what intake are they running.

 

Comments please.

 

Thanx, Dave.

 

PS: I don't mean to be thread-jacking, I'm hoping that my input will also help to determine an appropriate design for a carbon intake manifold as I think it would be really nice. The weight savings and no heat soak would be awesome.

[Dcrasta]

Only problem (headache) I would see with the ITB would be synchronization issues (they all must open correctly or some cylinders will 'work' harder than others) and restrictions with the TB being in the way.  ITB the tb represents a larger restriction in the port (percentage wise) than if you had say a Ford Style TB on a large plenum intake.  

[88whitestarion]

[

quote author=AustinTSI link=board=enginemods;num=1095891791;start=70#81 date=03/21/05 at 21:07:12]I would really appreciate any info on the affects of ITB. Also, I would like to know everyones thoughts on my impression that the magna intake doesn't seem to be working out as well as everyone was hoping. I only say this because I believe (maybe I'm wrong) that there isn't one person that is getting 400+hp yet. IS there anyone developing 400+hp and what intake are they running./quote]

 

I'm not convinced the Magna is the answer either. I been running the Magna for two years now. The torque is great, but the hp is lacking and I can't make power past 6200 rpm. I am about to break in a new engine with oversized valves, heavy porting, and a higher lift cam with solid lifters to see if thats the problem. If I still can't make power past 6500, the Magna is gone. I will go with a shorter runner intake with a larger plenum.

 

I like the Magna because it's relatively inexpensive, has the thermostat housing built in, has a water port for the heater, and looks like it belongs in the car. But if the performance isn't there, it's gotta go.

 

There is someone on ebay selling a new MPI intake that looks pretty nice. I like the shape of the plenum.  That might be my next choice if the Magna doesn't work out. A throttle plate for each runner will give very crisp throttle response, especially for a NA engine. However, for a turbo tapered runners might be a better answer and that would be difficult with individual throttle plates.

 

I think the ideal intake would have 7 to 8 inch tapered runners with a plenum about 50% larger than the magna. I've been looking and haven't found it yet.

 

Dave

[shift1313]

austin, as dc said the restriction and timing issues.  I think of itb setups as more for high revving engines because they help keep the velocity up at lower rpms.  This is why most motorcycles now run dual butterfly setups to aid velocity.  I dont think you are going to see any difference in plenums with an itb setup.  its going to be the least amount of restriction before the tbs that help and the length of the runners after the tbs.

[AustinTSI]

With the ITB manifold that I have it is only about 1" thick and it is designed for the DCOE TB's to mount directly up to it. I believe it is for the water passages as the manifold is designed to keep the water heater.

 

I don't know how much the ford TB's flow but I did calculate that a pair of 40mm DCOE's has the same surface area as a single 80mm TB. 45mm DCOE equals a single 90mm, and 50mm DCOE equals a single 100mm TB. This is in surface area only, I don't know what the flow rates would be but here is a graph that shows what the ITB DCOE's are capable of.

http://home.austin.rr.com/neozoe/CarStuff/TWM-ITB-Flow-Test-Comparison.JPG

 

As for the velocity issues, that is one of my concerns. I know that there was another person that I heard about through someone else (maybe the guy in CA with the white and blue car) that had the ITB setup and supposedly he had a problem with not being able to develop any real power until the upper rpm's. But the info that I got made it sound like he didn't have a very good design. Velocity and low end power are of the reasons that I am thinking of a runner/plenum design that would allow me to relatively easily change the length of the runners and the volume of the plenum so that I could hopefully find the optimum combination. If this works it would also allow people to pick what they want. Something with low end torque or high hp.

 

Dave.

[Chad]

The ITB pics is from Chauncys white starion, had a best of 9.51 in the 1/4 mile with that setup.   I had many conversations with him before he disapeared about that setup, said is had little or no lowend, to the point of not being any fun to drive, but made kiler top end.  

 

This is was made me design my intakes with 1.62" ID x 7 1/2" long runners and a ~18"x4" round plenum.  This translates to ~220 cubic inches of plenum and ~60 cubic inches or runner total.  Makes great torque, and still breathes freely above 7500 RPM.   Uses a 70 MM TB.  I personlay don't like putting any obstruction int eh runners (Butterflys) since that is where velosity is greatest and turbulence is highest.  I'd rather have the turbulent air flow over the butterfly upstream so the air can settle before entering the runner.

 

Keep in mind too, the 40 MM ITB butterfly has a shaft diamter in the 5 mm range, that takes up 2 square CM of the total of 12.5 square CM crossection of each runner.  You end up loosing 21% of your area to the throttle shaft with an ITB.  

 

On a 40 MM ITB setup, you -actualy- have 38 total square CM vs a single 75 MM TB with a of square CM of 41.2 (3.8 square CM of the throttle shaft is deducted)  which is only 9% shaft loss

 

Not saying ITB is all wrong, just think it's not the answer to our motors. Better to have a medium/large pelnum with medium length runners and a moderate TB (no more than 20% bigger than the IC piping).  Bigger/shorter just looses torque pn intake dimansions, and a oversized TB makes for poor streetability/tuning with little/no HP fgains  (been there myself).

[AustinTSI]

Nice to hear from you Chad. I'm not sure about Chauncys setup but I know that the one I had gotten info about was useing 50mm DCOE's which is why I thought they had no low end. 50mm is just too big and like you said, no velocity, no low end.

 

I've got a head at BCE Racing that is receiving the full treatment and I was going to match the head flow to the correct DCOE's. I'm guessing the newer 42mm or maybe the 45mm's.

 

I'm also planning on having velocity stacks inside of the plenum which should help. BCE is supposed to give me a bunch of numbers and suggestions as they said they have a lot of experience with DCOE's on other cars.

 

One last thing that I had been told by my source was that the ITB setup had very bad tip in response. I'm thinking that my source was talking about Chauncys car as this would make sense. I have been told that with an ITB setup you need to have a collector log of at least 1/2" ID that connects to the manifold reference ports of the ITB. This helps to smooth out the pulsations which cause low rpm response and in turn kill low rpm power. If you look in the pics of Chauncys ITB above you can see the reference ports are just connected with more hose (the U shape hose in the center top).

 

Again, this is just my thoughts and is meant to present alternatives, promote alternatives, and to gather info. I'm not discounting any of the previous designs, I just want to find a setup that will let these cars develop 400+ hp. I'm constantly debating wether I want to proceed with my ideas or just go with Chad's setup.

 

Can anyone provide the dimensions or flow data of the Magna intake?

 

Dave.

[artinist]

ITB is soooo old school. reminds me of alfaromeos. they are meant for NA cars where idling / driveability / fuel mixture was a problem when runing one big throttle body.

 

they have no business on cars these days especialy in a turbo application.

yea there is some kookoo at BMW putting ITBs on the new 7series but he is an idiot. the future is in direct injection.

 

the best intake for our car is the design chad uses on his intakes.

 

A: medium/short runners

B: large/medium plenum

C: throttle body size doesn't matter as long as its bigger than intercooler plumbing

[jinx]

pulsar gtir sr20det and rb26det skyline gtr run factory ITBs. They're sick beasts when modified with great throttle response. See some pesky little turbo 20V toyota 1.6L popping up too, still retaining oe ITBs. Speedtech got 470whp from theirs.

They didn't go thru all that effort and expense for nothin', eh.

 

it would be interesting to see the high water mark for the magna intake. I'd imagine the aussies have figured it out long ago.

Keep in mind that a setup like 88whitestarion's should satisfy 99% of all starquests.

(88, when you're done with your 'old' setup, my starquest would be the one left at the end of the driveway - empty engine bay, hood open) hehe

 

I'm curious to see specs and a dyno of Chads car, after hearing a couple fellow starquesters rave about a test ride.

Interesting intake comments btw.

On Chauncys' ride.... low end ? fun to drive ? 9sec et ? heavy car powered by a 4cyl ? Can't have it all, eh

 

I can recall one 240sx guy fabricate an intake manifold for his SOHC 2.4L, as per sdsefi.com tech page. The final product was ugly as hell, but he was blown away by the huge top end charge that single component made (no other changes to his turbo setup). In fact, "screw the dohc" was his comments... he was planning a swap. The stock 240 (KA24E) sohc intake looks similar to the magna.

[artinist]

magna runners are twice as long as they should be for this engine/car. however its great for the trucks. its a good direct replacement MPI intake but its nowhere near as good as a straight runner intake.

 

our engine is very very similar "technically and functionally" to the supra engine. what makes that engine tick makes this engine tick when it comes to making power. jsut copy their intake design, or rather their upgrade intakes.

[MidNiteRide89]

Ok, this stuff is a bit above me, but I will add the following.

 

In the Dec. '97 issue of SCC, Arlan Faustino went to an ITB and his quarter times slowed. He called other tuners and Pantera Specialists in CA told him to go back to a single throttle body.

Like art said, everything seems to be going to direct injection... now who wants to start work on that for our cars?  

[artinist]

Ok, this stuff is a bit above me, but I will add the following.

 

In the Dec. '97 issue of SCC, Arlan Faustino went to an ITB and his quarter times slowed. He called other tuners and Pantera Specialists in CA told him to go back to a single throttle body.

Like art said, everything seems to be going to direct injection... now who wants to start work on that for our cars?  

 

wow, Pantera specialist, that guy is still around? i think his name was lance or something. my buddy bought the TEC II unit and turned this car that i own now into an MPI in the back of his shop back in 1991. that guy is knowledgable but was as useful as a carrot. a royal A-hole. the guy wouldn't lift a finger unless money was flashed in front of his eyes.

back in those days he was using a TEC to run an engine they had designed which had electric valves. I think mercedes is finally this year coming out with an engine like that.

 

another inovations of the very near future.

a. 24 volt electric system

b. alternator and starter combo unit thats built into the bellhousing around the flywheel

c. solenoid controled valves

[Low White N Boosted]

damn i've learned so much from this post... still got alot more though i don't know s*** when it comes to ANY of this...

[shift1313]

if you really are going to carry on with this setup maybe think about a dual butterfly setup in each runner.  Would definately throw a wrench in the flow but may give some good bottom end response where the itbs seem to lack on turbo cars(not all).

 

art, any more info on solenoid controlled valves? that will make timing changes super easy but i wonder what kind of speed and reliability they can come up with  

[MidNiteRide89]

wow, Pantera specialist, that guy is still around? i think his name was lance or something. my buddy bought the TEC II unit and turned this car that i own now into an MPI in the back of his shop back in 1991. that guy is knowledgable but was as useful as a carrot. a royal A-hole. the guy wouldn't lift a finger unless money was flashed in front of his eyes.

back in those days he was using a TEC to run an engine they had designed which had electric valves. I think mercedes is finally this year coming out with an engine like that.

 

another inovations of the very near future.

a. 24 volt electric system

b. alternator and starter combo unit thats built into the bellhousing around the flywheel

c. solenoid controled valves

 

I don't know if he's still around today, but he was at the time of that article, 12/97.

I knew about the valves, but not the other two. Did you know about Saab's variable compression engine? It's not really new news at this point, but man what you could do with that technology!

[artinist]

I am pretty sure there is an industry set date to switch to 24 volts but i cant remember. it was rather soon though, maybe 2007 but i havent heard much since it was announce about a year ago.

 

thats the main obsticle to the electric valves since they require a lot of juice to move them at very high speeds.

 

i remember saabs variable compression. i never understood why they would not want to run an engine at maximum compression at all times?? anyway, their execution with the "cylinder head" changing angles where it mates the block was a pretty lousy idea.

 

what do you expect when their turbo V6 engines had a single turbo run by 3 cylinders on one bank of the engine only. oh and dont forget the ingnition keys that were next to the handbrake.

 

General motors has since kicked the mentally retarded out of that company it seems. they are making much more descent cars now in the past couple of years since they bought them.

[shift1313]

the funny thing about the variable compression ratio engine is they spent like 45 years trying to develop it and thats the best thing they came up with  ;D

[AustinTSI]

I may be out of date about this but from what I understood a lot of the Formula 1 cars run solenoid valves and from what I remember they did it for a number of reasons:

 

* no valve float

* variable valve timing (max HP and Torque)

* and eventually they would eliminate butterfly valve and throttle bodies.

 

I could very well be wrong about this as it was a number of years ago.

 

Dave.

[Metric-man]

Austin,

your correct cam less valve trains.. and that is part of the reason for increased electrical capacity.

 

artnist,

they (automotive designers) skipped 24 an went up to 48V but now they're thinking closer to 42V.

 

http://www.findarticles.com/p/articles/mi_...113/ai_81138565