im focusing on the same thing for my n/a lq4. have you done any of the math to get the intake runner size down or just shooting for the middle? i figured out to run twin throttle bodies you'll need to go down to 68mm which twin 68s equal out to what a 96mm single would give you for area.

this is what im thinking of

 

what are vehicle are you putting this on? if its a camaro your going to have problems with height restrictions, we ended up having to dimple the bottom of the plenums to clear the runners. The path from the plenum to the back of the valve is 12 inches.

 

i myself will be putting it in my 95 formula but as far as clearance i have probably 3-4 more inches than most do, i bought a fiberglass extreme dimensions 98-02 ws6 replica for my car and one night in a "rush" to get to my girlfriends house, i forgot to latch it... hit 45 mph and it came up and cracked my windshield. it split the hood in 2 on the seem that bonds the top shell with the bottom panel. its flimsy as a wet noodle at the moment but i bought a fiberglassing kit to give it another layer underneath and when i do this im gonna have my buddy weld me up an aluminum frame of 1/8 inch thick stuff to give extra support, i think all in all i should still have 3+ inches of extra space in my engine compartment.

what size intake runners did you use length x diameter? what size plenums?

 

I.ve studied up on what works for other intakes for years & got a little backup knowledge on other forums from a few who know a little (lot) more than me on intakes . One person is one of the gm engineers involved with projects such as the ls7 intake. Got a little general info from Tony Mamo also, can't go wrong there. Basically should come out as good as anyone working off known knowledge & not spending hundreds of hours dyno & flow testing multiple variables.

This was over 2 years ago when I first started coming up with sizing figures so I don't remember all the specs running through my head at the time. But the largest thing in my favor is going off a design that is superior powerwise throughout the rpm range.. The internals of a fast lsxrt, with a little porting is a great starting point, had dimensions, but can't find them now. The p.d. intake , osmo cross ram, x-ram & now the variram x are all pretty similar.

I was going to make runners shaped like the pd intake, which resemble the older c5r itb race intakes, but I don't have that much free time. The pipe I have is 2"nominal 316 drainage pipe, which measures 2 3/8 od & approx. 2 3/16 id. The shape of the ls1 intake runner 3" up is equal to approx 2 1/8" plus id.. Round shapes supposedly flow better at the important bell mouth entrances, which is what the osmo has. I have 13" now, but will likely slightly shorten for packaging.
I also will be machining all the taper I can into the ends of the thick pipe I have.

To make the portside runner shape as seen in tabletop pic, I layed the top on pvc trimboard to flatten the bottom without distorting the top & layed each side on an anvil to flatten with a 3 pound hammer. Went back & forth between sides & bottom with the beatings. Does take practiced skill to do, but not rocket science.
Working on finding or making something for some all out shaped bellmouths (velocity stacks) without spending $400 up on premades. This is a key area to a good intake, which is the worst area of the ls1 factory intake.
The plenum area is the less important area of the bunch, mainly can't be too small ,too big & has to extend enough past the rear cylinders not to starve them, another factory intake issue.
I'll be doing a 2 into 1 on mine, need some help deciding if a larger throttle body is much of a benefit for a mostly stock ls1. Still working out size.

I'm posting this project both for my benefit of knowledgeable people helping me out & inspiring others. In fact I challenge & dare anyone else to make their own manifold. If it comes out better than mine, I'll be happy.

My vehicle is the custom 2010 Camaro nose el camino, which has a pretty fair amount of room, except for the hood mechanism connecting bar behind the intake limiting the ps rear area.

Southpaw, first saw an intake like yours in tenacity Camaro pics.I may shape my plenums similar to yours. Did you do an intake only swap to tell what difference it made?

 

Damn, thats bad! good work! Did it perform well for you? Better then a LS6 intake at least? It looks great.

 

sounds like great advice. and as far as the 400 dollar velocity stacks... no problem, im a cnc machinist and love excuses to make **** when i have free time. i was actually gonna machine the intake flanges, bottom and top of the plenum (separately of course) and then the throttle body mounting plates. in fact, if it ended up turning out well, i wanted to make a few variations after i get my motor together and start experimenting with runner size and all that jazz. realistically i want it to look very similar to that one i posted a pic of. maybe not that wide though.

 

I do a lot of cool stuff without a proper machine shop, but I have to cut back a little on time if I ever want this to be a reality. Going stainless over aluminum is a bit harder also.
If I don't find anything premade for cheap, I may consider 4" delrin stock to turn on a wood lathe for bellmouths.

 

yea working in a shop spoils me from time to time. if i feel crafty i can go to my grandfathers and use his table lathe and milling machine... cnc is just soooo much easier in the event i wanna duplicate a process. note to self, buy a 30 or 40 taper vertical for gramps... haha 40-150k later

 

The car hasn't seen a dyno since the intake was switched unfortunately. Just a street tune.

 

have you noticed any top or bottom end gain?

 

Wondering the same. Also like to know what you did as far as bellmouths at the end of the runners.
Not much time to work on things this time of year, but got all 8 runners cut & bent sideways to make the plenums come out more even with each other.

Strongly considering making clear lexan covers on sides of plenums to expose the bellmouths.

Also trying to decide if a larger & more optimumly shaped bellmouth is worth the trouble or not.

 

Search stainless steel egg cup, they are cheap and may be big enough turned upside down and cut out the bottom for a bellmouth.

 

Saw threads on those years ago, but haven't been able to locate any.

Got a little more shape into the pipes last week, got them fitting better, will post new pics later.. My thought now on plenums is a dual plenum on each side where the main plenum has a slot in it & a 2nd plenum has the tapered shape & feeds the air in , resulting in better distribution.https://www.google.com/search?hl=en&...31%3B752%3B800
If I do this they will be underneath the main plenums. Also may just use round tubing for the main plenums, as in mock up, & have clear covers capping off the front, which will let you see the velocity stacks inside. Wondering how that would look?

 

Got a little further along after playing with several design changes. Made my velocity stacks & started shaping plenums.

 

Started welding up the thin 20 gauge stainless sheet metal plenums. Warpage is so hard to control that I don't think I could get them done good enough to look proper in mirror finish. Heavier stainless is out of the question, so I may have to just make the plenums out of aluminum like most everybody else.
I have some .063 3003 h/14 sheet in stock, but I'm thinking .090 would come out nicer. Also wondering if there is another locally available sheet aluminum grade that would polish up or hold a shine better than 3003 grade?

 

Picked up some .090 aluminum to remake plenums. Also designing 4 bolt flanges to connect each runner to the plenums. Will weld velocity stacks to runners . This will allow me to still use my stainless stacks with aluminum plenums & also eliminate the upper rubber connectors. Similar to Ozmo setup. Should look cleaner.

 

Cool! Keep it up jlcustomz!

 

Last view of the stainless plenums, which I'm reshaping from aluminum.

 

Got plenums mostly shaped from .090 aluminum. Made flanges on sides of plenums to attach runners . Upper hose connectors will be eliminated soon.

 

Looking really nice. Great fab work.