AGood2.8

Well its fathers day- so I have time to sit around and brainstorm-

Now knowing my headers are on the way, I have a little time and motivation to plan this motor.

I've decided to scrap the current upper plenium porting process, Was very strongly debating sending the 3 intake parts to Extrude Hone. However, the upper and middle intake runner bends are tight and restrictive.

Here's my next project to start tinkering with over the next few months. I plan to fabricate the it uot of aluminum stock, then have a friend who owns "Custom Metal Fabricators" weld it all together for me- This will take some time to fab but here goes nothing. It will shorten the runners and give a more direct and plentiful air charge over the stock plenium.

Project: 85 2.8 bird

your design looks like a modified 3.4 intake, especialy the head on shot.


edit: for really bass a$$, do twin throttle bodies, all sensors to one, & cai/ram air to each tb :rockon:

AGood2.8

.

Dale

iTrader: (12)

So you would keep the middle section of the intake, and just create a new upper??

devianb

If I was considerin doing a custom intake I would do both upper and lower intakes. Good luck in having something like that fabricated. Even Accel had sealing problems with the early ones.

AGood2.8

Yes, and I can port the middle and lower extensively to match the heads because the runners are a straight shot(easy access).

AGood2.8

.

Dale

iTrader: (12)

I think it could possilby work.

Anyway you could relocate the TB up higher, so its a strait shot, rather then angled??

I know the throttle cable would have to be moved up, but is that possible?? (I never looked, I don't have these connections)

AGood2.8

Actually it won't go higher for two reasons-
1) The bracket for the cable would have to be altered extensively and the angle would not be right.
2) STB and Hood cleareance issues.
I have measured and calculated everything as close to possible- even the ramp volume. The tb mount to a square port (aprox 2 1/2"x 2 1/2"). That Square port ramps upward and alters into an opening into the plenium that is a retangular that is 4" wide. Note that equal cubic space would be 2" x 3.125' opening. The reason that I am increasing it is because with the ramp up, I don't want to bottleneck the CFM of air flow and cause hesitation. It should remain the same CFM or taper larger for good flow. If it were to slow from same size or smaller as it travels through, then it causes a high pressure zone after the TB but then a low pressure zone before the runners causing sputter when cracked open.

pontiacguy1

Just making the plenum larger will help the thing Rev better! Will look cool, too.

AGood2.8

base done-

88camarov6

wow, that looks great. I can't wait to see it finished. What kind of performance gains are you expecting?

AGood2.8

Anything better than the stock plenium will work for me. Here's a shot of the walls being fabbed so far- notice the front right and rear left plenium bolts. I had to mill aluminum rod into those areas for a symetrical fit. Also the front right bolt has to support the a/c bracket which I plan to alter slightly and retain A/C comfort in this car- Its going to remain a street car.

When it is finished, I've decided to test this plenium on the current 2.8 motor that is in the car while retaining the stock TB and stock middle and lower manifolds- Its the best way to tell how responsive it is by comparing it directly to the stock setup without any other changes taking place at that time. First consern will be if the design and volume of the chamber is stable to run the motor properly.

6SPEED84Z28

iTrader: (1)

nice it looks like pretty much the design i was thinking of. i guess our disscussion gave you some incentive to have something done about that upper plenum. do you know what the plenum volume is yet. i was hoping to build something with about 5 to 6 liters.

AGood2.8

Hey Greg, Yes our conversation gave me incentive- I figure I will go to the Supersix heads instead of doing my own- Takes too much time to do things right (I'm always busy) Its going to be hard enough keeping this project going in orderly fashion. Figured with the Supersix heads that I had better get an intake married to them that is comparable.

Plenium volume including the TB neck is 248 cu. inches- I have to look up a convertion chart for liters

Edit: corrected to 248 cu in- not 248 sq in.- Thank you from post below

88camarov6

I think you have 4.06472 liters if I did it right. *edit* don't you mean Cubic inches?

AGood2.8

I fixed the above -thank you.
I also double check your calculations and you are correct- 4.1 liters

Conversion forCubic inches to liters- just divide 248 cubic inches by 61= aprox 4.1 liters
Thats great news on my guess work. Greg and I discuss things futher this morning and he informed me that the race LS1's are using custom pleniums with a volume of 10 to 11 liters- I'm half the displacement and 1/3 to 1/2 the hp so this sould be a very good experimental size. Heck, the stock plenium is only about 1-1 1/2 liters before the runners start.

Oh yes, We finalized things with my headers order and he is shipping them today (drop off- they go out first thing tomorrow morning- Never thought I'd use this stupid cloud figure but here goes (I'm pathetic):lala: :lala: :lala: :lala: :lala: :lala:
Note: The above clouds represent my six combustion chambers swirling for joy
---------------------------
This project will be on hold for at least a week- I have a very busy schedule coming up- please be patient, I'll post updates when things are progressing.

AGood2.8

Edit: I'm deleting pics- saving space- check for updated pics below.

AGood2.8

.

camarogirl18

iTrader: (2)

looking good cant wait to see the finished project...

need some motivation??!

AGood2.8

I decided to weld up the inside as well for added strength- only because I have grinded the outside welds away so much for looks. Just want to be certain I have no leaks- Only clearance problem I have is with the schraeder valve cap- with the cap off it will fit. I will just grind underneath a small bit (1/16" to 1/8" max) and it will fit. Next is to install the tb linkage fitting and test for clearance. Any alterations to this will need to be done before I weld the lid on, As well as finish smoothing the weld beads inside for smooth flow up the ramp.

pasky

Ummmm.....Wow , gonna keep an eye on this topic.

Gumby

Might be worth while to take some extra time and make the lid removable. Then you could allways play with "runner" ribs inside to direct flow.

Wouldn't ya hate to hafta hack it back open later???

Matt

AGood2.8

that defeats the point- An open plenum allows for shortened runner length and the ability to draw air from the open space- air flow is in abundance to each port.

Gumby

I'm talking just some small ribs, not full length or high, I have seen it somewhere and some reason its sticking in my head.

Something to break up any turblance maybe is what im thinking, I know I have seen it before.

Think of the air comming into the box, it gonna hit the back and "swirl" on either side. so just a few "directional" ribs makes the air break up into a small "vortex" and hopfuly over each intake port.

I am not bs'in ya here just trying to help. I think there is something to what i'm thinking about but can't pin point down how to say it.

I have seen it use in a similar situation so that you get quote more smaller turblance areas where you want them.


here is a crude drawin...

Matt

AGood2.8

Here's where you are misguided- The intake air is DRAWN, not FORCED into the plenium. Thus air is sucked towards each runner as it is drawn through the TB. it doesn't need directing, directing causes more trubulance and restriction.

I do certainly appriciate imput/advise, however please don't feel offended if I debate them constructively. I of course have resureached this well before I designed it.

Gumby

Well the title of your thread says "RAM Air" so its really
"Sucks Air"

What if you go turbo later???

Why I am even thinking on that curve. If its has more volume and pressure than can be sucked in, it could do that.

-----


What we need is a FI system that need no air input numbers and you can just run open ports on the heads. Have 6 little air cleaners.

Matt

AGood2.8

Ram air referes to "Tunnelram". My label is not the best by saying "ram air"- I know many confuse that with a air filter/ air box routing ducts. These open plenum chambers are actually refered to as "superrams".
-------------------------------

I'd give my left nut for this FI system-

2_point8_boy

HOLY CRAP!!! I want that motor!!! It's friggen' sweet. I would almost give both nuts for that thing.

german-motorsport

Any news on the intake?

AGood2.8

I'm pacing myself Actually I am working on it as we speak- just came in to take a break, get a snack, and check some things on the computer- Please note that this project will take some time for me to complete (maybe a month maximum, hopefully sooner) I am only able to work on it in my spare time. Next week I start a another major construction project and will be very busy again. I am currently milling the TB face plate and have to cut and positon it into place the weld and grind. I'll post more pics by this weekend.

AGood2.8

I pulled the car down breifly to do a test fit- Got the shraeder valve clearance in good shape. Had to adjust the TB faceplate mount angle just slightly for clearance of the STB and a slight IAC issue- I barely rotated it to the right angling the IAC up a tad higher to clear the wider intake ramp- Linkage hookup and freedom is great. Heres a flow shot of the TB port and ramp-

AGood2.8

Bottom of ramp shows fitting modifications I had to make- Still need to grind more for better appearance. I have a good 30 HRs into this already- Lot more work than it looks. Mostly alot of grinding.

AGood2.8

.

AGood2.8

Hours of grinding and smoothing welds, getting closer.

F585

Looking good! What kind of welder are you using?

AGood2.8

Lincoln Mig 175pro With Aluminum kit and 75%argon/25%helium shielding gas. Mig aluminum splatters everywhere- imposible to do appearance welds with it on aluminum- I'm great with steel. I have done a water test to check for any porosity leaks in welds- so far so good.

funstick

im going to make a piece of small but constructive advice. if at all possiable i would rewordk the inlet shape of the runner and build a venturi into you new upper plenum to feed the runner. look into venturi flow and how it can create tremendous air velocity and overall flow. in fact with as far along as you are id sugest just working in some new runners. couple of peices of round tube and some plate and your there. would allow for incoprating things like venturis inlets and would most definately increase airflow. at the minimum i would sugest a hardy raidious leading to the runner at a minimum. sharp surfaces are the last thing you want. it will shear airflow when what you trully trying to do is organize it. anyways ive siad enough today.

peace out

AGood2.8

I haven't even begun to port the runners yet- I just for starters matched the top to the stock middle runners and plan to port it extensively before I weld the top on. Thank you though.

socialdeviant

your going to have major flow problems with that intake. Period.

You have a great open chamber, I applaud, but the air has absolutely no direction, leaving the air that is drawn in, in complete turbulence. No smooth stream flow capibility at all.

If you had a turbo, I would being saying otherwise, but with a N/A Motor, that has to be one of the worst designs I have even seen. Sorry but true.

Granted, your absolute CFM capibility is well above stock, but the incoming air had no controlled direction of flow.

Think/say what you want, but the laws of dynamic physics' don't lie.

I applaud your effort, but your next attempt you may want to take flow dynamics into account on the design.

I will attach a design you may want to consider next time.
Pics too big. Sorry. But try creating individual runners to each port.

AGood2.8

I guess you would expect the V8 ones to be crap also? Same design.