Plenum size and runner length for 250 whp

[RSS]

I'm building a 2g 7 bolt 4g63t and target power is about 250 whp, turbo code is TD04 16g. I'm going to make sheet metal intake manifold and I know good plenum size is 1 - 1.5 times of engine size for nice powers, I my target hp is not huge, I wanna know what's best plenum size and runner length for my application with very nice throttle response.

 

[Canadian_CD9A]

You're not likely to create anything that performs better overall than the stock intake manifold at that power level. The engineers put a lot of time into the design for best performance at 250 hp - it's not starving for air with that plenum volume and you're only going to increase turbo lag, not quicken response, if you make the plenum and runners larger.

 

[jdxnc]

Just get an Evo2/3/RVR intake manifold if you want to upgrade over the stock 2g, it's more than you need and honestly I don't think you'd see any difference at that power level. A boost controller and wideband will get you in that power level without much issue. Intake manifold is one of the last things that needs an upgrade on these cars.

 

[RSS]

You're not likely to create anything that performs better overall than the stock intake manifold at that power level. The engineers put a lot of time into the design for best performance at 250 hp - it's not starving for air with that plenum volume and you're only going to increase turbo lag, not quicken response, if you make the plenum and runners larger.

I don't have access to any stock or aftermarket intake, I have to make one!

I don't have access to any evo or dsm intake and I need to know size and dimensions.

Just get an Evo2/3/RVR intake manifold if you want to upgrade over the stock 2g, it's more than you need and honestly I don't think you'd see any difference at that power level. A boost controller and wideband will get you in that power level without much issue. Intake manifold is one of the last things that needs an upgrade on these cars.'t

 

[bastarddsm]

The runners need to be like 10-14" long, and should have a little more cross sectional area than the valve curtain area at max lift. I'd shoot for somewhere around 2-3insq

 

[RSS]

Do you mean " head runner + intake runner = 10-14" " or just intake runner 10-14'' long?
what about plenum volume?

 

[biglady112]

Is there no way to purchase a stock manifold from any number of vendors or members and have it shipped internationally? I know I have sent stuff overseas a few times and it worked out just fine.

 

[Mech Addict]

If you can’t even get a stock intake manifold, how in the world will you get the other parts to make a running engine? It does seem like the power you seek requires only minor modifications from factory original. Jdxnc has identified the most critical part, which is a slightly higher peak boost pressure. What will you use for fuel (octane and method of rating , RON, MON, average, E85?). That also plays a big part in what engine mods to target.

 

[Canadian_CD9A]

I don't have access to any stock or aftermarket intake, I have to make one!

What country are you in that makes it impossible to get a stock manifold? This is a very helpful community - someone should be able to send one to you, regardless of where you are located.

 

[RSS]

International shipping is forbidden for us.

 

[EC17PSE]

so you in Texas or no as i dont know what planet you are on right now if shipping is forbidden

 

[RSS]

If you can’t even get a stock intake manifold, how in the world will you get the other parts to make a running engine? It does seem like the power you seek requires only minor modifications from factory original. Jdxnc has identified the most critical part, which is a slightly higher peak boost pressure. What will you use for fuel (octane and method of rating , RON, MON, average, E85?). That also plays a big part in what engine mods to target.

It was very hard for me to get needed parts. It needs a lot of money, time and search. Unfortunately, In my country exact octane number of gasoline is unknown but people say its 87 to 95 octane EURO-4.

What country are you in that makes it impossible to get a stock manifold?

It's impossible. Only way people can help me is by giving me the size and dimensions in order to make intake manifold.

so you're in Texas or not? As I don't know what planet you are on right now if shipping is forbidden

It's not a joke. I'm physics teacher and my monthly income is less than 250 USD. Can you imagine?

 

[EC17PSE]

Child labour? Seems a thing here

 

[Canadian_CD9A]

Sounds like a country that’s the most sanctioned on earth right now..

 

[RSS]

Common guys.. I just need intake manifold dimensions

 

[Canadian_CD9A]

I'd keep it closer to 2L plenum volume. Manifolds like the JMF Race below badly hurt response and low-RPM torque, so size the plenum smaller.

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Runner length probably doesn't matter as much in a turbocharged application since the "response" you feel is mostly going to be from boost pressure and not air velocity, but the original-style manifold (left side) had longer runners, and is a great match for the engine character. I'd honestly try to replicate the original manifold as closely as possible.

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[RSS]

Thank you very much. It's very hard to get dimension from pics. I'm agree with you I should go similar to stock one. I have to search volume and size but there is no useful info

I'd keep it closer to 2L plenum volume. Manifolds like the JMF Race below badly hurt response and low-RPM torque, so size the plenum smaller.

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Runner length probably doesn't matter as much in a turbocharged application since the "response" you feel is mostly going to be from boost pressure and not air velocity, but the original-style manifold (left side) had longer runners, and is a great match for the engine character. I'd honestly try to replicate the original manifold as closely as possibl