intake plenum

[sledneck22]

I am trying to design up an intake plenum for a low boost rear mount turbo system.
For those of you that have done this before, what are your thoughts on the attachment. It is rough drawn because I don't have exact dimensions off from the intake off the machine yet but the shape and form would be similar in production build. I am leary if there is enough air volume in there or if that even matters. I am also worried about even air distribution. Anyone ever seen any issues with over boosting certain cylinders or would there need to be some plenum dividers within the intake?
Planning on using aluminum for material. I am also planning on installing a BOV on the front of the plenum.
What are everyones thoughts and opinions. (other than why don't you just buy an intercooler)
Thanks

 

[kinger]

Looks pretty restrictive, I would definitly add some material to the side where the air is coming from to make the 180 degreen turn.

Corky Bell's book on intercooler design had a section on volume and requirements. I would do a quick search around the net for intake volume requirements. It DOES matter and if its too small the system will not work properly.

 

[rlcofmn]

I'd make it round, round is way stronger. The flat sides will either need to be really thick or use stay bolts through it to hold the pressure from ballooning it. 2" round with 4 ports and a 90 coming into the end for your charge tube with be very structurally strong and flow well.

 

[DaveForsyth]

Airbox parts

I have designed a lot of intakes for turbo sleds.
1=Velocity stacks is important
2=Stacks in middle of airbox
3=Volume for engine + RPM length of runners
4=Smooth flow without pressure drop from turbo to intake.
I have sold parts to One Stop Performance, Hurricane, Northest turbos, Ted Jannetty, Greg @ GNS,
Let me know if you want parts to weld up your self and I can help.
250-836-4422

 

[sledneck22]

So when you say velocity stacks and stacks in the middle of the airbox are you refering to some kind of "air diverter" for lack of better terminology. Just to keep the air flow directed to the leaving 4 ports on the intake? And to prevent "swirling" within the chamber? Can you explain your points a little better Dave?
Thanks,

 

[DaveForsyth]

Intake on air boxes

On any motor to get max performance you need a calculated airbox size for RPM and size of motor.
Next would be tapered stacks and with over 180 degree located in the middle of airbox.
Tubes welded to the outside surface is not a good thing for tuning.
Length of tubes for RPM also play into where it makes power.
All this info is very old from books like Gordon Jennings on 2 stroke and 4 stroke stuff from motorcycles I worked on since 1975.
R1 Yamaha many years ago could make 200 HP n/a
Bigger airbox is always more power. Long tube stacks for torque.
Hope this is what you are looking for!

 

[sledneck22]

Well people, I have just about everything needed for my turbo as in parts. Except an intercooler and/or intake plenum. I am only running at max 7 psi this year until I get running boost dialed in on the sled. Then next year I can upgrade.
I need some insight on what to do. I could make a simple round intake plenum with stacks coming off the tube going into the intake. I would rather not but it will be simple and handle the low boost. Does anyone have some kind of template or ideas on making an intercooler/plenum or perhaps want to sell one? I'm just kicking the tire on what I should and want to do here.

 

[sledneck22]

One other thing,
If anyone has dimensions to the core size of an intercooler and/or dimensions of the stacks going to the intake, port sizes and locations, I would be much appreciated as I would try and build my own. I don't really care which intercooler you have but basic width and length dimensions to order a core and build the plates and plenum.
Thanks,
Kyle

 

[nate007]

On a rear mount turbo you shouldn't have any volume issues unless you're running too small of charge tubing. If you had a front mount turbo with too little volume you might have some issues with the throttle being twitchy, but volume requirements are far more important with a supercharger than a turbo. Just don't go too large or you'll have problems getting the BOV tuned correctly and throttle decel problems will likely result as the engine has to get rid of extra charge air.
Your intake design would work fine, as long as you're not shrouding the flow of air in or out by turning too sharp. Twice the diameter of the tube is a good rule of thumb for minimum bend radius (beyond any velocity stack or "bell"), so if you have a 2" inlet pipe, I'd try to keep at least 4" of clear opening in front of the openings. Rounding off the edges of the plenum may help increase performance, but not likely in any way you'll ever notice. Pressurized intakes don't follow the same physics as naturally aspirated intakes, and airflow isn't as critical in some areas. Always maintain an air charge into the throttle bodies that is as straight as possible, and as long as possible, but what happens between makes less of a difference as long as you're not restricting flow anywhere.