Custom mani discussion.

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ycode90

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I think I wanna make a new intake . I have a lot of aluminum stock layin around . I'm also thinking of incorporating a water to air intercooler . How much internal volume should there be inside the intake ? Is this gonna make a difference ? Whats the best suited TB for the airflow of the v6 ? Also thinking the injectors could be on each side . Think this would hurt anything ? This would save me a lot of piping . It would also have the oh shit factor when opening the hood. This will be for my SC car so low end isn't what I'm goin for.



I want experienced intelligent conversation . If you have no experience in fi high horsepower engines just read do not post . This is not a why would you or that's dumb discussion . :thankyou:

Discuss
 

Off Road SHO

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I have made sets of aluminum extensions that will bring the bottom of your (or anyones for that matter) new plenum up so that it clears the fuel rail. In case you don't want to mess with re-locating the fuel rail system. They are the same shape as the phenolic spacers that I make, but machined out of solid aluminum. You will have secure longer bolts inorder to fasten your plenum to the heads. I have one set left if you're interested.

I also have the "base plate" machined out of aluminum. This piece bolts to the risers with those longer bolts, and becomes the base onto which you weld your plenum of choice.

I myself am working on a plenum that accepts a twin screw compressor. But it sure isn't cheap.

Tom
 

hawkeye18

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IIRC GeekSHO made a custom intake for his Roots-blown car. I don't recall if he did any fancy tuning or anything on it; pulse timing and scavenging and all that kinda go out the window when you're stuffing 12 psi into it...
 

ycode90

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Thank you but I already made some risers . I want to move the injectors . The idea I've got in mind is just what you stated a set of "risers" that bolt down a base plate . The plenum is my concern . Is the vol. of it that important ?
 

ycode90

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IIRC GeekSHO made a custom intake for his Roots-blown car. I don't recall if he did any fancy tuning or anything on it; pulse timing and scavenging and all that kinda go out the window when you're stuffing 12 psi into it...

Who only see's 12 psi ? :swing:
 

rubydist

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The lengths and volumes of the production SHO intake are carefully tuned to the useful rpm range of the engine. Its going to be very difficult / impossible to do much to improve that other than polishing / extrude honing the bores to provide smoother airflow, unless you are changing from the natural aspiration and 7000 rpm redline of the production engine.

What are you planning to do different?
 

hawkeye18

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lol @ people who only read the first 5 words of any post.

tl;dr if you're not gonna read the whole post, don't post in that thread, k?
 

illSHOyou

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I think I wanna make a new intake . I have a lot of aluminum stock layin around . I'm also thinking of incorporating a water to air intercooler . How much internal volume should there be inside the intake ? Is this gonna make a difference ? Whats the best suited TB for the airflow of the v6 ? Also thinking the injectors could be on each side . Think this would hurt anything ? This would save me a lot of piping . It would also have the oh shit factor when opening the hood. This will be for my SC car so low end isn't what I'm goin for.



I want experienced intelligent conversation . If you have no experience in fi high horsepower engines just read do not post . This is not a why would you or that's dumb discussion . :thankyou:

Discuss

More Info Needed...

How Much Boost?
Desired Throttle Response?
RPM Peak Power?
Any Cams?
Can the Transmission even survive? LOL :laugh_ti:
 

Sho Amo

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i will tell you that with a smaller intake volume you will probably see more boost with the same pulley. more boost doesnt equate to more power its about cfm. you really need something direct and free flowing.
 

ycode90

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More Info Needed...

How Much Boost?
Desired Throttle Response?
RPM Peak Power?
Any Cams?
Can the Transmission even survive? LOL :laugh_ti:
15 psi
Not a big factor
7800rpm
3.0
Most likely no.
i will tell you that with a smaller intake volume you will probably see more boost with the same pulley. more boost doesnt equate to more power its about cfm. you really need something direct and free flowing.
Hence the reasons for doing.
 

BlackonBlack89

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Why?

maybe will not improve anything (not a shot at u, but u potentially could make less power) A centrifugal s/c SHO needs TQ not HP lol

You would definatly want to search for a turbo charged SHO with a custom intake. I forget his name. It was a Gen 2 green and was atx. Maybe some good info in his old threads (if he posted bout it, i forget)
 

illSHOyou

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15 psi
Not a big factor
7800rpm
3.0
Most likely no.

Hence the reasons for doing.

Why not just pump one more lbs of boost in the intake and call it a day?

The only reason I would build a intake manifold for the SHO is if the engine was fully forged, dry sumped, and 10,000 rpm. Otherwise there is many other ways to make power, and the SHO intake is p r e t t y.

I would have a suggestion for the above application if your interested?

Plus, at 10,000 RPM the transmission will handle more peak power...
 

Off Road SHO

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Ycode,

If you're doing a positive displacement blower, Roots or Lysolm, you don't need a plenum with a certain volume. In fact, the smaller the plenum the better.

The only reason the manufacturers do the long tube runners after the intercooler is for packaging purposes. The air/water intercooler has the best heat dissapation coefficient but it needs to be near the hottest air to absorb the most heat. Once the charge air is cooled it needs to get back up to get into the head.

On centrifugal type chargers, both blowers and turbos, I believe that plenum size comes into play, though I couldn't tell you what the plenum-to-displacement ratio is.

Still the cheapest way to go is like IllSHOU said; "add 1 more pound of boost and call it a day". But if you're WANTING to spen time and money, I can definitely help you out there. Been there done that, have the receipts to prove it. And no money.

Tom
 

rubydist

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pulse timing and scavenging and all that kinda go out the window when you're stuffing 12 psi into it...

You want to explain the physics of that statement? Because that's not how the physics I learned works.

Pulse timing and scavenging change due to the different air density, but they are still there and still important. More important, in fact, since you are trying to move more mass of air.

Runner cross section size is also very important to the resultant performance. One of the significant reasons for the twin torque peak on the production SHO engine is that the secondary opening changes the cross section size of the intake. Here is a link to more reading on that topic:
http://www.rbracing-rsr.com/runnertorquecalc.html

Here is another interesting site regarding intake designs:
http://www.team-integra.net/sections/articles/showarticle.asp?ArticleID=471 btw, for forced induction, you just change the VE to a number larger than 1.0 depending on the psi you plan to run (i.e. 15 psi would be VE of around 1.9)

btw, I expect that moving the injector location will be an exercise in frustration, as the injector timing will be affected, and I am not aware of any programming tool that allows modification of the injection timing.

Hope this makes up for my not reading carefully this morning before I had my morning coffee.....

edit

Tom posted his response above while I was writing - and I respectfully disagree with some of his comments. I know from experience that runner length after a Roots blower makes a difference, and changes the torque peak rpm. Somewhere I might even have dyno charts showing that. I think the plenum volume after the Roots blower is still important, its just that its difficult to actually make one small enough that its too small given the configuration of the blower. If the reflected pulses from the individual intake valves disrupt the flow in the plenum, then its too small, regardless of what is driving air into the plenum.
 
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HotRodKid

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IIRC GeekSHO made a custom intake for his Roots-blown car. I don't recall if he did any fancy tuning or anything on it; pulse timing and scavenging and all that kinda go out the window when you're stuffing 12 psi into it...

wrong.

picture a burning building full of people. telling people to run faster is NOT the proper answer to there being only one fire escape. the right answer is "the building should have been designed properly in the first place"
 

Toolman

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Challenge - Someone with a custom sheetmetal intake manifold make more power than me with my crappy dual runner Yamaha designed manifold. Reward - I will buy every ounce of beer/liqour you can drink during a SHO convention (unless you are St Louis SHO).

Not to crap on your idea y-code (but I guess I kinda did already, sorry), but why? The ONLY reason I can see for a custom manifold would be weight savings (the stocker is pretty heavy). It certainly is not a restriction, and will not be a restriction until well after your 17th grenaded transaxle. If the SHO intake does not impress people, I do not see how a sheetmetal intake will. Heck, about the only thing impressive under the hood of a SHO IS the intake. And if you are only looking to see 15psi, then any changes to the intake manifold are rather superfluous.
 
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The only reason I would see to change manifolds would be if you planned to rev beyond
8-8500 rpm.After that I could see the stocker start to become a restriction.
Even at that point I'd base a new manifold off the stock runners with new surge tanks,Y area and TB.
 

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