Making a intake manifold...

[Redline240]

Well the car comes off the road for the winter friday. Not really winter here yet but we had one day of snow and some salt on the road so thats enough for me. So this weekend i start my long awaited KA-T project. I just started a machinist course a few weeks ago and i'm gonna do a lot of the fabrication at school. While a few custom manifolds have been made no info has been given on them. So i figure it would prove to be a great benifit to the KA-T community to discuss all the options and general info on fabricating one.

I'm just gonna list off a few things we can disscuss;

1. Alluminum vs mild steel vs stainless2. Flange thickness3. Runner length4. How to go from a round runner to the flange, the intake path is far from circular. Possible drastic porting?5. Plenium size/volume6. General plenium shape and design7. Throttle body choices(stock, Q45, other nissan, domestic)8. Injector bosses and how to make them

Now obviously all these will differ not only from personal opinions but for the many applications the KA-T is used for. So for simplification we'll consider two broad applications, street/strip and drag.

Maybe with the help of knowledgable members such as WD and Ivan to mention a few, we can design a intake manifold or at least educate guys like me who are fairly new to part fabrication.

Here are some helpful links to custom intake manifolds;http://toyotaperformance.com/i...e.htmh ... chinta.htm

Lets keep this clean and to the facts!

Redline

[klattr1]

well, theres a few being made right now. (boost designs, ivan is making one, and i believe wasabi garage).

just buy one pre-made because there is alot of considerations and research needed for a successful design (runner length, volume-1.5 to 2 times bigger than displacement of motor quoted from Ivan, Idle Air provisions, water neck placement, flow benching, dyno testing)

[nr2134]

Ivan has been doin research on the intake mani for a while now and he is making good progress. He doesnt want to copy someone elses design and call it a day. Otherwise the mani would be out already. This seems to be a trend lately though when it comes to intake mani designs. Having control over the whole design and in house fabrication he will be goin through a bunch of designs before he can release it for us to play with.It will be designed for the KA motor not a copy of a 2.0L or less of a displacement motor which will make more hp than the stock one, but it wont be optimal. The wait will be worth it.

[npaulseth]

I am also looking into intake manifold deisgn. There are many many variables when you look into designing a manifold. I wouldn't be too worried about what matterials to use. You just want to make sure that the welds are good, and you have nice thick flanges.

[nr2134]

You are right. There is alot of variables to consider. Thats why Ivan is considering having 2 different designs of the mani. One for the the people that will be making less than 500hp and one for people like Ivan and I.

[npaulseth]

Hey, don't count me out of the picture

I PMed Ivan some good information from NARB that showed how you plug in all (or most of) those variables into creating a intake mani. Grape Ape Racing had some very good information in manifold design. Although, 95% of the intake manifold design pages are using non-boosted applications when calculating the manifold design. I'm not sure how big of a difference that will make, but it could be big. I can't wait to see how the final product comes out.

Thanks,

Noah

You are right. There is alot of variables to consider. Thats why Ivan is considering having 2 different designs of the mani. One for the the people that will be making less than 500hp and one for people like Ivan and I.

[Redline240]

Stop littering up the tread!

And i see no reason why i should just give up and wait to buy it off someone else. Thats the whole point in making one so i don't have to. If i had the money to buy every little part pre-made then i wouldn't have started this thread.

I'm sure Ivan will design a superior manifold, but if mine makes more than the stock one and 20hp less than Ivan's then i'll still be happy cause i made it. And i saved a fortune. I can't be the only one thats considering making one.

I hate it when people put so much faith in people online they barely know...Ivan has been a great help, but i was into the SR and RB fourms and seen all the guys brought down by Dauntless a year a two ago and it makes me wanna think for myself until something is actually up for sale...

So if you got nothing worthwile to post other than wait for Ivan, then move along and come back when someone has posted something informative. Not every part in a catalog is better than what someone with even simple skills can make...

Redline

[nr2134]

Sorry for jacking and littering the thread a bit, but you may not get alot of info from people in the know since its kind of a secret still.But if you are gonna be making the mani yourself I can give you a couple of guidelines to follow.Dont make the runners longer than 7", make sure the plenum holds at least 4L and that it extends towards the firewall after the last runner @ least half the distance of the distanc ebetween runners.Also taper the plenum or the runners going towards the firewall.Sorry I cant be more specific.

[npaulseth]

It never hurts to go and buy some "auto math" books. I have some very good specifics on how to design an intake manifold, but would rather not give them out if Ivan is planning on using them (no, I did not give Ivan any specifics on making an intake manifold, but we have both read from a similar source).

[crzycav86]

If you're an engineer or really good at physics a good "auto math" book would be "Engines: an Introduction". It discusses nearly every aspect of engine tuning and theory, and it has an extensive section on manifold tuning. It was written for 3rd year engineering students, so it's not for the faint of heart... but it's one of the best... good luck.

And another good link: http://enaf1.tripod.com/teche.html

[IvanAtSPRacing]

I do want to contribute to this thread. I think that RedLine has been one of the most grown up people on this board and always willing to help (and learn) which seems to be a rarity on most forums.

I am having a problem finding good factual information on "forced induction" manifolds. I have found and read and been refered to some great informative info on designing manifolds for NA cars but there just seems to be nothing out there for turbo cars.

On NABR right now we are discussing this same thing. Here is an example of whats happening. Some have stated that velocity stacks inside the manifold will help, although the research has shown on a flow bench, the velocity stacks disrupt the flow and make it choppy. But this is under vac and not boost. Now check out F1 cars where they have velocity stacks in their plenum. This would be the extreme end of the boosted spectrum. Why would they use them if they didnt work? What is a good test to see how a manifold will react under boost other then make one and try it out?

I think its going to be difficult to quantify what design wise makes a great manifold. I think a good educated guess and some luck will probably be the only way.

IMO, short tapered runners for velocity, low pressure area around the injector, large enough plenum to work as a boost capacitor but not so large you gain signifigant lag getting it filled, possibly a taper in the plenum will help, angle of the TB in relationship to the runners should be looked at.

Working around the factory water outlet is going to be tricky. With all the idle controls, EGR and PCV, design will be complex. To make a manifold from scratch that will accomedate everyone will be very expensive. Making something from the existing manifold will be a lot easier, but it will need to be done WELL.

I am sorry if this all seem so vague. I am just in the beginning stages of the race mani and will kind of see how it goes.

[Redline240]

Thanks Ivan, for both the compliment and info...i have to agree, there's little to nothing out there with regards to manifolds under boost. Here's what i'm thinking so far, tell me what you think.

1/4" aluminum for flange18 gauge aluminum for pleneumRunners around 3-4"Q45 TB (i plan a full 3" system using a V-mount setup)

I knew i had to extend the pleneum past the last runner, half the distance between runners like mentioned before sound good. Thanks nr2123! But why 4L capacity?

Personaly i want a "extreme" street setup, so as long as i'm boosting by 4k i'll be pleased.

I'm gonna be ordering the AEM EMS and i want to run a Map setup, what on the manifold is needed? Assume i have a bare pleneum with TB attached, what NEEDS to go on? No emmisions stuff...

Redline

[IvanAtSPRacing]

We are using the AEM to control the factory IAC only on the S13. My plans for the race mani that I am building for myself and Norbert is to run a 3" Wilson Manifold TB with GM IAC. The IAC is built into a flange that comes off the bottom of the TB so no hoses to and from the IAC. You can also use the AEM to bump up idle when you turn your AC on so you can do away with the factory setup. You will need provisions to run a MAP sensor and having the IAT sensor in the comon plenum would be ideal. I personally will be modding the PCV setup to vent externally to keep the intake free of oil. All the rest of the crap is going.

I am going to be using a 1" flange with 4 to 5" runners. Plenum will be 1/4" material (probably cut and sectioned 4" aluminum tubing. Runners will probably be 2" .250 wall aluminum tubing. Injector bungs machined into flange.

[npaulseth]

Generally, the plenium is supose to be 1.5-2 times the displacement of your engine. As for the flange, I would make it a little thicker than 1/4", some people have had problems with too thin of flanges.

Noah

[Redline240]

No harm in goin thicker, i didn't know...which is why i started this thread, cause guys like me don't know. Alright so 1/2" or 3/4" flange.

Ivan, why so thick material for the plenum? I wanted 16 or 18 gauge sheet metal so it'll be easy to heat up and bend by hand, or use the roller if need be. Is there any reason that sheet metal wouldn't hold the boost?

Oh, and i had an idea for testing the welds. Its proably been done a million times before or its a usless test but here goes;

Make a plate to cover over the flange and TB plate, bolt it up and use silicone all around. On the TB plate cover weld in a bung to connect a air hose too...slowly raise the psi on your compressor and check for leaks and cracks. I'm pretty sure this would work, but would 10psi of air pressure being held in the plenum be equal to 10psi during a boosted run? If not, why not?

Redline

[npaulseth]

I would almost put money on: he is using that think of material so it doesn't blow apart at this boost levels. It's fairly easy to crack welds at 600+ HP.

[IvanAtSPRacing]

All of the intakes we make for the 2JZ and 7M are make out of thick 3/16 to 1/4" aluminum tube / plate. We cut and section plate, tube, channel etc and weld it all together. Welding 18ga aluminum will be really tricky. Beefy aluminum is much easier to weld. and will hold its shape much better. Your intake mani will also balloon when pressurized. You might not be able to see it, but it will. Constant expanding and contracting will eventually crack welds etc. With enough pressure, the intake can also explode. On Ethan's 980 WHP SC300, we had a NOS backfire and it actually peeled the intake open like a banana.

[NateDogg]

I would suggest becoming a member of theoldone.com. TOO (the old one) is, IMO, the leader in flow design. His carbon fiber intake manifolds outflow ITBs. Also, there is quite a bit of info about forced induction intake systems on the forum that will answer most (if not all) of your questions.

[NateDogg]

Here's a better one.:

http://www.theoldone.com/archive/intake-design.htm

[Redline240]

What about flaring the runners where they meet the plenum...same shape as the V-stacks but weld the flared edge directly to the plenum as apposed to protruding into it...think this would prove helpful? Oh and what about my pressure test idea? What ya think of that?

Redline

[NateDogg]

I think welding the flared ends of the runners onto the flat plenum is the best way to achieve the ideal radius. As TOO says, they used velocity stacks in the 70's and the radiused plenum idea above is better for distribution and flow.

[Redline240]

What about the ID of the runners, and thickness? Thats pretty much the last thing to know, before i start it anyway...then i'll have a billion questions...i'll post pics of the process!

Redline

[NateDogg]

Stock ID is about 1.85. Runner ID fixes the peak horsepower RPM while runner length fixes the curve.

ie. long runners lift low rpm power while short runners lift top end power.

Fat runners increase the peak horsepower numbers. If you want a screamer going to 2" would be a good upgrade. 5-9" runner length and 2" D runners would be good to increase top end.

From Alex Graham Bell's book, "Forced Induction Performance Tuning"....

He basically says Runner size for a turbo 4 valve car should have a length of 260-300mm (10-12") including the distance from the valve seat to bellmouth face in plenum. So that means approximately a 7-9" "runner". The diameter should for a all-out drag car should be 1.12-1.18 x inlet valve diameter. So assume 36.7mm inlet valve diameter..For a street car you want runner length about 350-400mm and runner ID to be x.99-1.05 x intake valve diameter.

Plenum size for a turbo engine should be .8-1.5x displacement.

There's lots of other good info in his book. It's a good read with lots of Nissan-related dyno testing. You should pick it up off Amazon.

EDIT: After reviewing the book, I've determined the "inlet valve diameter" is the intake valve diameter in the head. This is clear because or 2 valve heads the multiplication factor is about 20% less than for a 4 valve head. So for a KA24DE the intake valves should be max 36.7mm. I also altered my post above to avoid confusion. So I'm sorry Ivan and Redline if your posts look stupid, or you can just delete them for future people looking up this thread.
Modified by NateDogg at 3:58 AM 11/7/2004

[Boost_Veteran]

here's a good link that talks about full races prototype intake manifold. The pics are for honda engines but the KA should look similiar. As stated the design is very close to the one larry made but not carbon fiber. You might get some good ideas from it eventhough it seems like it's 9 pages of people just saying "i want one". . . .



link http://www.honda-tech.com/zerothread?id=979697

[IvanAtSPRacing]

Stock ID is about 1.85. Runner ID fixes the peak horsepower RPM while runner length fixes the curve.

ie. long runners lift low rpm power while short runners lift top end power.

Fat runners increase the peak horsepower numbers. If you want a screamer going to 2" would be a good upgrade. 5-9" runner length and 2" D runners would be good to increase top end.

From Alex Graham Bell's book, "Forced Induction Performance Tuning"....

He basically says Runner size for a turbo 4 valve car should have a length of 260-300mm (10-12") including the distance from the valve seat to bellmouth face in plenum. So that means approximately a 7-9" "runner". The diameter should for a all-out drag car should be 1.12-1.18 x inlet valve diameter. So assume 60mm inlet valve diameter..For a street car you want runner length about 350-400mm and runner ID to be x.99-1.05 x tb diameter.

Plenum size for a turbo engine should be .8-1.5x displacement.

There's lots of other good info in his book. It's a good read with lots of Nissan-related dyno testing. You should pick it up off Amazon.

This book sounds like it might have some good information in it, but I think you might be mis-stating some of the info. According to what you have written above about street cars, it says that runner diameter should be about the same size as the TB. So a 3" diameter runner for a 3" TB? Those would be some FAT runners. If you meant plenum diameter, then for a plenum the same displacement as the motor with a diameter the same size as the TB, then this plenum would need to be about 33" long. Its a little confusing.

I might have to pick the book up and figure out what he might be saying.

Or if you like, please scan some pages and email them to me.

Thanks
Modified by IvanAtSPRacing at 8:22 PM 11/5/2004

[Redline240]

I'm glad you said that Ivan, cause i must have read that 10 times trying to make sense out of it....lol...might have to pick up that book...

Redline

[IvanAtSPRacing]

you think barns and nobel might have the book? In their Turbo / supercharger section? Right next to the NAWS section..

Yeah.. I really wish natedogg would reply... I am interested in what the book really has to say..

[NateDogg]

Please see my edited post above.

Using a bit of common sense, experience and trial and error is I guess the best way to figure this out. Honestly I wouldn't experiment with anything over 2.25" ID runner. Some guys did a 2" ID runner about 8" long and claimed "awesome top-end" a while ago on FA with a KAE-T. Street cars and all out drag cars are going to be completely different animals here as shown by the "formulas".
Modified by NateDogg at 3:51 AM 11/7/2004

[WDRacing]

I just got back from SEMA, so the threads have not been moderated for a week. I've begun trimming the fat from several threads, this being one of them. If your post was deleted, email me, [email protected]

[WDRacing]

Just somthing I'm personally looking into with my mani. I'll be using a phenolic spacer in between the head and the intake flange, the spacer will be 3/4" with the mani flange being 1/2 thick. The Phenolic doesn't transfer heat. So the intake will stay quite a bit cooler. Its not a new idea by any means, the Domestic guys have been using them as spacers for years now. But I don't know of anyone other then Team Mopar who's using them on a turbo 4.

Here's somthing I'm willing to do just to see the comunity come along faster. When my manifold is done, not soon by the way, I'd be more then happy to send it off to whomever else has one completed, just so we can get comparible dyno information and flow benching if you have one available. Mine is going to Extrude Hone after completion to work out any of my newbish port mistakes, so I'll have flow bench info available.

On a side note, since any intake mani design is based on science and math, both of which will almost always repeat themselves, using a design similer to one that already proven isn't really a bad thing. It may in fact be the best way.

The Veilside Manifold for the Supra is one of the best manifolds ever built in my eyes. SO I'll most likely be modeling mine after that unit. Which has definitly been proven to yeild BIG numbers under high boost....I'm starting to ramble.

WD