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well my new facination is playing with the tig, and aluminum. Ive decided to build a custom intake manifold. I will use the stock manifold, and cut it off right after the plugs for the injectors.

I was told that shorter stacks, and larger plenum would be better for topend. Given this will most likely be a 99% a straight line drag car, this is exaclty what im looking for. Does anyoen have any reccomendations as to size/shape? Thanks guys.

Also, anyone got any other ideas for performance-based aluminum projects?..something about aluminum, and nice gorgeous tig's are so much more fun and satisfying than nasty steel and mig.
 
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/\ i wanna see pics, so cool when people make their own shit intake setups
 

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higher rpm motors would use short runners i.e. edlebrocks design short runners, large plenum good between 7000 and 10,000
 
Z

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whatthehell1051 said:
/\ i wanna see pics, so cool when people make their own shit intake setups
is that sarcasm? My reason for doing so, is quite this: i simply do not have the money to purchase the best of the best, for every part i need. I built my own log style turbo manifold, that came out great. After deciding to go a different route/turbo with the car, i will be adding a wastegate flange to it also.

After figuring out regulations/specs i will also be building my own battery box, and probably fuel cell as well.

Yes, the intake is for a dohc ZC, turbo application, with is what is expected to be a high hp build (tuner toy rods, srp or JE pistons, posted block, gt2871, gt3031, or gt3076 turbo, and my pre existing NX nitrous kit converted to direct port)

Anyway, what is considered "large plenum, and short runners"? does anyone have a rough idea just to get me started? ive decided to go with 60-61 t6 aluminum, because that is what im most comftable/familiar with. Ive noticed some people build a rectangular plenum, some round, and some start rectangular, but by the 3rd runner, they start to taper/curve one side.

again, i know my finished product may not flow quite as well as an aftermarket off the shelf item, but being a fulltime student in my senior year, taking up most my time, a parttime job, its just not possible to buy everything top-of-the-line. Im trying to build the engine as best i can, and then put it on the track. As the season goes on, i can then test/tune and decide what needs to be upgraded the most.

Thanks guys, i appreciate it.
Chris
 
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Discussion Starter #8
oh my bad seriously i meant it foreal like i enjoy seeing people make their own intake setup.not putting you down at all sorry about that.
 
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whatthehell1051 said:
oh my bad seriously i meant it foreal like i enjoy seeing people make their own intake setup.not putting you down at all sorry about that.
oh, haha its all good man. i was just a little confused by the way you worded it... Ive never been "well off" by any means, so ive always learned to make due with what i have, and try to make the best of it. Im the kind of guy that will spend 5 hrs modding existing parts to save 100$, because i just dont have it to spend. :lol:
 
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/\ lmao yea me to money is something i like keeping in my wallet. lol
 
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anyone?? Ive never built an intake before, and as far as demensions, i have no idea where to start...
 

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if you have NO IDEA what goes into it, your more likely to come out with a horrible design than something thats actually going to work. don't get me wrong im ALL for DIY projects. im a hands on kinda guy. but the perfection that has to go into the IM is well above my skills and many others.

sorry for sounding so down about the idea. maybe just study some of the aftermarket designs. and yes you want a larger plenum with shorter runners. still, the plenum cannot be too large or your start reversing the gains.

i honestly wish you the BEST OF LUCK
-Luke
 

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If you have an old Intake mani laying around, you might want to get the specs of that. Then ask someone on this site what their specs are of their aftermarket. As in, dia of the plenum, inside and outside dia. and the distance end to end, along with the taper of the plenum from runner to runner. That way you'll get a better functioning setup.
 
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yeah.. ive got my oem manifold. I dont know if im missing something here, but by the obvious differences in the edlebrock, and venom plenums, it seems to me that it is more of a volume thing than actual shape... this is going on a high boost engine anyway, so as far as i understand, as long as things are shaped so transitions are smooth, and unblocked, it shouldnt be much of an issue. Ill play around with the relativity of the flange size, compared to the rest of the venom manifold to find my demensions out i guess. Was just hoping maybe someone had already been down this road. Oh well, thanks a bunch guys. Greatly appreciated.
 

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I think the biggest factor you need to take care of is the runner/flange transition to your head. That will be honestly what will really make or break your setup. Next you might want to think about making your fourth runner maybe a bit larger. I'm not saying by much at all. But due to that runner being the furthest away, and it being at a loss for flow, you have the chance to balance out the tables of flow and volume. But for actually using a correct shape for the plemun, almost anything will work. The box shape works becuase the mass amount of air volume it can feed, therefor it doesn't have to worry about if there is a 100% clear path of flow. It floods everything, that way it can not miss. anyways best of luck man, just sit down, do the math, and you'll be fine! It's all about planning, if you have a bad plan, all will be a rough path. If you have a good plan, you'll have a great path to follow.
 

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shorter runners for a NA car, make a plenum with volume close to 50-60% of engine displacement. Oval is probably the best shape for the runners, but you can use circular pipes as a 'close call'. Best thing to do would be to use stock runners (shorten!) and build a custom plenum on them.... similar to Edyn's new "ultimate B series manifold".

As for plenum shape. I'd say just about anything goes from square to round... experiment with shape and volume - just know that air is a fluid and it will fill it's container, however, when air is moving through a pipe system...it tends to travel at high velocities in the center of the pipe and very little air flow is on the edges.

What'd be really nice, is to get a set of ITBs working, and then build a plenum around them and then run a cold air or short ram intake (similar to pocket rocket's 315whp H27, or the BMW M3 stock).

Nathan
 
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Discussion Starter #18
yeah.. i think i may try ITBS later on, but im changing so many things as it is (connecting rods, pistons, compression ratio, adding a turbo, injectors, ect ect ect) that i think i will use this intake until i get it tuned, and then decide wether ITBs are an option or not.

I noticed you said 60% the cylinder volume 60% of 1600cc is like 960, which turns out to a plenum 10.5x2.25x2.5"....seems quite small.

This is going on a turbo application (fairly high boost) what would you reccomend for plenum size?
 
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Discussion Starter #19
well i just played with that Venom manifold pic and came up with a 1215cc volume for their plenum, and around 3" long runners... Does that sound about right for a turbo application? The 60% nathan reccomended comes out to 960cc....
 
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