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Location:
The realist ghetto area P...
Registered:
April 2005
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Location:
Rockhampton, Queensland
Registered:
August 2004
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Re: custom plenum dimensions??
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Tue, 18 October 2005 22:06
 
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well not to give any good ideas away or anything that i have used for my design. The plenum chamber volume should apparently be twice that of the engine capacity. So in our case it would be 3.2Litres. But some performance guru's beg to differ and say that 3.2Litres would be a minimum and larger is better given your desired application. Short length runners are ideal for different situations and setups and so are the long length runners. All depends on what you are going to be doing i suppose.
So yeah, hope this gave you some ... thing.
Dan
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Location:
The realist ghetto area P...
Registered:
April 2005
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Re: custom plenum dimensions??
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Wed, 19 October 2005 01:10
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thanks mate!
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Location:
The realist ghetto area P...
Registered:
April 2005
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Re: custom plenum dimensions??
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Wed, 19 October 2005 01:11
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how bout the runner sizes should they go from big to small vice versa??
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Location:
Rockhampton, Queensland
Registered:
August 2004
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Re: custom plenum dimensions??
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Wed, 19 October 2005 02:08
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no, try to get your runners equal in length. Have you ever heard of the term "tuned length runners" ? they basically a certain length depending on your application and are equal in length and size.
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Location:
Canberra
Registered:
May 2002
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Re: custom plenum dimensions??
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Wed, 19 October 2005 02:41
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The factory 4AG inlet runners are a pretty good length, I'd suggest trying for something around 1" or so shorter.
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Location:
Canberra
Registered:
June 2003
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Re: custom plenum dimensions??
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Wed, 19 October 2005 03:23
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The longer the runners the better bottom to mid range torque you will have....shorter runners give better top end power. Actual ideal lengths are engine and use specific but staying as close as you can to the factory or a little shorter is a good rule of thumb.
Plenum size should be roughly 1.5 to 2.5 times engine capacity but there are so many variables that impact on this that any volume in that range will be fine for general performance use. To chase every extra hp lurking in a setup requires testing testing testing so for most of us the rule of thumb type approach is fine.
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Location:
Melbourne
Registered:
May 2002
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Re: custom plenum dimensions??
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Wed, 19 October 2005 03:25
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its been documented that the plenum volume should be anywhere between 1.5 to 2 times that of the engine capacity. Which would make it be 2.4-3.2 litres. As regard to runner legnth make it as physically as long as possible to fit under the bonnet and keep it tunned length, otherwise your gonna end up with runners that are optimised for a power band to rev 10krpm and beyond (thats with 4 inch runners from the valve seat) and to keep it optimised for a lower revving engine the legnth becomes stupid and well beyond what you can fit under your bonnet. I dont have exact figures at hand but i will post them later on how to calc runner legnth.
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Location:
The realist ghetto area P...
Registered:
April 2005
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Re: custom plenum dimensions??
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Wed, 19 October 2005 13:31
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good stuff!!! thanks heaps im getting all excited n shit i wanna start chopping things!
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Location:
Rockhampton, Queensland
Registered:
August 2004
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Re: custom plenum dimensions??
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Wed, 19 October 2005 13:33
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haha lol 
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Location:
The realist ghetto area P...
Registered:
April 2005
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Re: custom plenum dimensions??
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Wed, 19 October 2005 13:35
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hehehehe
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I supported Toymods
Banned User
Location:
Brisbane
Registered:
May 2002
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Re: custom plenum dimensions??
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Thu, 20 October 2005 03:19
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Where are you guys getting this info about plenum volume?
Regarding plenum volume, Corky Bell says:
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An air intake plenum sould be several times larger than a cylinders displacement.
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Further on in his book he says:
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The plenum volume should be a function of engine displacement-in general, 50-70%.
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I supported Toymods
Banned User
Location:
Brisbane
Registered:
May 2002
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Location:
Terrigal
Registered:
May 2002
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Re: custom plenum dimensions??
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Thu, 20 October 2005 04:13
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I heard many different ideas on this one.
From 80% engine size to 2.5x engine size.
In the end I set down some requirements (must have min 75mm of air space over the runner bellmouth, must have pace between bellmouth and any wall - 50mm if possible).
Now from my 1st runner to 4th runner (including bellmouths and some space before and after each one so not close to a wall) was a bit over 400mm..
Height, 75mm being the lowest over 4th bellmouth.. Tappering up to 95mm over the 1st runner.
Then its not a box either as i wanted some space around the sides of the bellmouths, so more oval shape..
But do some quick calculations of a oval shape with above measurements and you end up with over 4lts.
So 2x engine size was the smallest i could make the plenum i felt. That isn't taking into account runner volume, or throttle body to plenum volume either.
Stuffed if i know how you can make a plenum 80% engine size and have it flow well?
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: custom plenum dimensions??
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Thu, 20 October 2005 05:29
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Joel, i took some pics of the TRD 3SGTE (from JGTC supra?.. at Toyota Amlux) that makes some stupid amount of power... the plenum is very small, and seems more like a device to direct air to the ports, as opposed to a reservoir for holding pressurised air. i dount it is even 100% of capacity.. maybe closer to 50%?
the cast exhaust manifold is also decepitively simple.
I'll put them up on new forum this weekend if i remember 
from memory, it kinda looks like Yellorollas plenum.....
Cya, Stewart
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: custom plenum dimensions??
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Thu, 20 October 2005 05:30
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| TurboRA28 wrote on Thu, 20 October 2005 14:13 |
Stuffed if i know how you can make a plenum 80% engine size and have it flow well?
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oh, looking at cyl 4, i was wondering how it could get any air at all.. but i guess it does...
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Location:
Terrigal
Registered:
May 2002
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Re: custom plenum dimensions??
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Thu, 20 October 2005 05:34
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Is that more for outright power though, than a healthy midrange?
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Location:
The realist ghetto area P...
Registered:
April 2005
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Re: custom plenum dimensions??
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Thu, 20 October 2005 05:42
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okay!! sorry guys but i have no idea what the hell is going on!! can sum1 pin it down for me on what measurments i will need to gain good mid range to higher rev approx 7k rpm , diameters of runners? length of runners? litres in the chamber?
please amyone?!!!
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I supported Toymods
Banned User
Location:
Brisbane
Registered:
May 2002
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Re: custom plenum dimensions??
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Thu, 20 October 2005 06:06
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| oldcorollas wrote on Thu, 20 October 2005 15:29 |
Joel, i took some pics of the TRD 3SGTE (from JGTC supra?.. at Toyota Amlux) that makes some stupid amount of power... the plenum is very small, and seems more like a device to direct air to the ports, as opposed to a reservoir for holding pressurised air. i dount it is even 100% of capacity.. maybe closer to 50%?
the cast exhaust manifold is also decepitively simple.
I'll put them up on new forum this weekend if i remember
from memory, it kinda looks like Yellorollas plenum.....
Cya, Stewart
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Just email me the pictures now!!! I want to see!!!
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: custom plenum dimensions??
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Thu, 20 October 2005 06:10
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| TurboRA28 wrote on Thu, 20 October 2005 15:34 |
Is that more for outright power though, than a healthy midrange?
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most likely just for higher rev range... i think it was pulling 460Nm and around 500hp? i took a pic of the specs too. it looks weird tho.. hmm, hard to explain...
sorry Cool1, they are at home.. and i am giving a lecture this afternoon... maybe tonight 
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Location:
Lost in the K hole
Registered:
May 2002
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Re: custom plenum dimensions??
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Thu, 20 October 2005 06:12
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| LAA.80E wrote on Thu, 20 October 2005 15:42 |
what measurments i will need to gain good mid range to higher rev approx 7k rpm , diameters of runners? length of runners? litres in the chamber? please amyone?!!!
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*oh thats an easy question*
me thinks someone needs to do some research - far and wide. i doubt anyone here will give you a pinned-down answer at all.
it took me weeks of calculations, research and a very expensive computer simulator to figure mine out, and its still all a bit of guesswork.
and do you really think you can manufacture tha parts to the exact specifications you come up with anyway??
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I supported Toymods
Banned User
Location:
Brisbane
Registered:
May 2002
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Re: custom plenum dimensions??
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Thu, 20 October 2005 07:32
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| oldcorollas wrote on Thu, 20 October 2005 16:10 |
sorry Cool1, they are at home.. and i am giving a lecture this afternoon... maybe tonight
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Alright then... 
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Location:
The realist ghetto area P...
Registered:
April 2005
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Re: custom plenum dimensions??
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Thu, 20 October 2005 08:06
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im pretty sure it wouldnt, BUt i know it takes heaps of research and shit thats why im here askn those who have had experience b4 as though i have neva got one dun b4, thats why i need sum pionters from people!
kapish!
thanks
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Location:
Terrigal
Registered:
May 2002
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Re: custom plenum dimensions??
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Thu, 20 October 2005 20:42
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I think everyone has given you some pointers man.. I reckon you just wanna be spoon feed the info?
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Location:
The realist ghetto area P...
Registered:
April 2005
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Re: custom plenum dimensions??
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Fri, 21 October 2005 05:46
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ummm no not really, i thank you guys for your help thats all.
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: custom plenum dimensions??
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Fri, 21 October 2005 06:40
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| Cool1 wrote on Thu, 20 October 2005 17:32 |
| oldcorollas wrote on Thu, 20 October 2005 16:10 |
sorry Cool1, they are at home.. and i am giving a lecture this afternoon... maybe tonight
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Alright then...
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http://toymods.net/forums/showthread.php?t=351
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Banned by his request
Location:
moved to tamworth
Registered:
July 2002
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Re: custom plenum dimensions??
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Fri, 21 October 2005 11:31
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mate if your not going to go over size valves,bigger springs,port the hell out of it and flow it that much that it cost more than the engine,stick to the standard on an atmo 4age
mick
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Location:
The realist ghetto area P...
Registered:
April 2005
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Re: custom plenum dimensions??
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Fri, 21 October 2005 16:24
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thats fair enough
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