Budget LS1 cross ram intake

[jlcustomz]

I'm attempting something most experts would caution against. This will be a low budget/high labor project. Will look similar in shape to the performance design intake , but with a 2 into 1 merge on plenum to mount stock throttle body.http://performancedesignllc.com/xr/
My first attempts at keeping costs low is cutting up a stock ls1 intake to leave the first few inches of runners to attach to with quality rubber connectors & clamps. ( seen this on 4 cyl setups). Planning on making runners 12 to 13" long for good torque, Probably alittle taper bigger twoards ends , Definitely with bellmouths in plenums, And the straight shot should be good for top end. Material will be aluminum or even stainless steel.
Trying to gather as much info as I can to not just be guessing here.Hope to at least not loose any power anywheres. This design is not common because of space requirements ,complexity & cost.
If I use stock intake, will have to connect to D-shaped portion of runners.
Plan B will be buying & cutting up edelbrock alum intake so I don,t have to guess on injector mounting.
Anybody got any good info on what I'm trying to do here on designing??

[Twentyover]

This help any?

http://www.sdsefi.com/techinta.htm

[jlcustomz]

Thanks. This being written in 99' is pretty much the same basic design I saw being done in a 2007 ford focus forum.This reinforces that some basics used such as straight runners with velocity stacks & large plenum area are good airflow improvement over space constraint designs.
Trying to find info about whether runner shape per size has much effect as to being rectangular, d-shape, or round. ??? Or if a slight taper larger in size twoards the end of the runners helps more than velocity stack only. ???

[jlcustomz]

Trying again to see if anyone here has a little hard knowledge on efi intake design , Mainly plenum sizing is where i need help. Here,s a post on ls1 tech with pics that will help better vizualize what I,m tryin to do here.
http://ls1tech.com/forums/generation-iii-external-engine/1518676-performance-design-intake.html

[cornfedbill]

Resurecting an old thread. I just found this.

I was responsible for the development and flow work on the LS7 intake. We had a lot of interesting ideas, but were constrained too much by cost and packaging to create a more radical design than what went into production.

Since we were not able to optimize the runners and plennum due to those constraints, we chose to cheat a bit and use a large amount of taper in the runners to improve flow. The runners are not really tuned for any specific RPM range. They are just tuned to flow as much as possible.

The cross-ram design has fewer compromizes. I am not a big fan of separate plenums, but know that it can work well.

You will need to make sure that the plunum extends beyond the last cylinder to prevent a ram affect that can make it go lean. This can be an issue with stock LS intakes. You will also want a very smooth transition from the plenum to the runners. Sharp corners will actually choke the flow and create a smaller effective runner diameter. Make it look like a trumpet.

There are a lot of theories on plenum volume. Without CFD models, it is hard to determine what is best. The stock LS7 would likely benefit from twice the current plenum volume, or thereabouts. Your motor is a bit smaller and would need a bit less. I would start out with a tube that is about 3.5 inches in diameter or has the same cross sectional area if it is another shape. I would also make sure the area of the runners just after the transition from the plenum at least 1.5 times the area at the entrance to the cylinder head. 2 times the area would not be a bad choice.

As for runner length, again there are a lot of theories. Generally longer runners with a smaller diameter will give you a very tuned response at the low end. Short fat runners are better for high end. Runners with a lot of taper and a very gradual transition from the plenum will tend to have a broader less peaky powerband. I prefer a medium length runner with a lot of taper. I would shoot for something similar to the factory intake in length. I think somewhere near 10 inches might be a good start.

Good luck.

[jlcustomz]

Damn Bill, need to thank you twice in one day. Yea the guy crazy enough to fab a 2010 camaro nosed lifting hood el camino is crazy enough to try this one. Will be working on it a little at a time. I already got an old ls1 intake & chopped it up to just the lowest portion( d-shaped) that I can get a rubber connector over. I will need to hot air weld up some extra material on the outsides to make it rounder for the connectors to seal. I made a couple of rough wood patterns to estimate the runner curvature , length , & general layout. Once I decide on size, I probably will have to weld up steel forms to hammerform the runners in 2pcs with seams on top & bottom which will be tig welded. Not sure if I'll have to just buy bellmouths or if I can setup to make some. The plenums I was leaning twoards tapering smaller twoards rear & yes,past the last runners. I might even try to make clear covers on the sides from possibly ceramic glass so the bellmouths can be seen, sound cool?? I may lean the plenums down a little heightwise and they will transition back to 1 single opening with a plate that I can start out with my stock tb for now & maybe go bigger later. For the basic runner dimensions, I was wanting to get the exact dimensions from thefast lsxrt, which is basically a crossram in a breadbox. My educated guess fine tune dimensions from there. I was thinkin approx 12'' runner length, as I could use a street low end boost as much as higher rpm's.
There were some older posts under this title that explained a little more of my thoughts, which i haven't thought about in a while. probably won't start back on it till maybe spring. Are you familiar any with the fast lsxrt?
Well I,m glad to hear my thinking ( from research) sounds to be inline with a gm engineer's. So if I build it as I,m thinkin about, do you think I stand a good chance to at least not loose anything anywheres(other than time & sanity) & hopefully have some decent all around rpm gain from this non-space constrained design even if it's an educated guess.??

[cornfedbill]

I think you are on the right track. The LS1 intake is very constrained due to the low profile. Actually the LQ9 truck intake is much better in many ways.

I took a look at the LSXRT intake. It is a big improvement over the LS1 and even the LS7. It would not be a bad intake to use for a starting point.

12" runners wtih a good amount of taper and very gradual transitions from the runners to the bellmouths should be sufficient. I would avoid super long runners like the old Chrysler cross ram intakes with the carbs over the wheelwells.

For the clear sections I would lean towards Lexan (polycarbonate). It is what bullet proof glass is made of. It is not too expensive and is easy to work with.

The taper in the plenums should not really make much difference as long as the rear runners do not become choked. It might look cool though. You may want to tie the two plenums together somewhere so they can "talk". This should help the ECM keep up with what the engine is doing and help balance things out.

Just make sure whatever you do is strong. If the engine backfires, and it will, it can generate enough pressure to damage the intake. We sent a prototype to GM to use on one of the first LS7 engines. We warned then that it was a dyno only sample and would not be safe on a car. Well, they got excited and put it on a car. When it backfired it went full throttle with no way to slow it down. If not for the emergency stop button that is on all prototype test cars, it would have been ugly.

This sounds like an interesting project.

[jlcustomz]

Bill, this would have to be an interesting project for someone that would loved to have designed something pretty similar-ie, less hp compromises & ultra cool looks.

Don't worry , no wheelwell length runners here. 11" to 13" are my boundaries.

Lexan if I do clear plenum covers was actually my first thought. Remember I'm the guy who molded his own 2010 camaro lights from leftover materials.Somebody at a show recently thought lexan wouldn't hold up. Looked it up this morning, starts to mold at 300, melts at 420. Nylon 66 is approx 400 , so it should be ok.Got what I need including woodworking equipment at my day job.

I couldn,t find an older thread where I better explained things, but there is a pic on page 5 of the widebody thread in multimedia section of a premade supra intake with balance tube at rear & 2 into 1 connection at front.This is similar to what I had in mind, I,m not getting into2 throttle bodies or anything. I,m no computer tuner either. Will have to pay someone before & after to dyno tune(EFI Alchemy) 1 hr south of me. Also the old c5r intakes are pretty similar to what I,m thinkin for runners & bellmouths. And also I pm'd with Tony Mamo of afr research before & may ask for his runner dimensions after porting a fast lsxrt.

If I do it to where I feel happy with it, does it sound like a big risk connecting to a nylon intake with rubber connectors. As i stated earlier ,I will have to add material to the outsides of the runners by hot air welding & make the d-shape rounder.I feel a nylon base would help for heat soak issues that worry so many people, the aluminum portion won't be up against the engine & is plenty open to airflow. I could even possibly find some type of checkvalve to mount somewhere to aid in possible backfire protection.

My other reason for using part of an LS1 base is it is a budget project- material wise that is.

Also is center of a rear plenum tube as good as any spot to mount a map sensor?

[cornfedbill]

My other reason for using part of an LS1 base is it is a budget project- material wise that is.

Also is center of a rear plenum tube as good as any spot to mount a map sensor?

The intake is Nylon 66 with about 30% glass fill if I am remembering correctly. The glass fill is important to the strength of the material. If you add a blow off valve, you will add some margin of safety.

The center of the rear plenum tube should be fine for the MAP sensor. It needs an area where there is not a lot of flow to influence the reading.

[jlcustomz]

Still haven't had any time to work more on this project, but considering another thought for the fabricated upper cross ram dual plenum part to attach to my stock nylon ls1 base;;;;polished stainless tubing approx. 2 1/4 diameter.The intake base at attaching point is pretty much d-shaped, so it won't be much of a transition to round. Won't have taper to the runners, but can have a really good bellmouth at the ends to help velocity.

Some imports have stainless intake manifolds, such as by Kinetics, claiming better thermal properties than aluminum.http://www.importtuner.com/tech/0605_impp_nissan_vq35de_intake_manifold/photo_01.html
May also use some design aspect off the NRE X-ram in development in my design.http://www.lsxtv.com/news/video-nelson-racing-engines-x-ram-intake-makes-690-hp-on-496ci-lsx/

Just still thinking, not yet doing.

[jlcustomz]

Took the project back out of the box recently & starting playing with some stainless pipe I had after seeing some actual stainless intakes online. Still in VERY ROUGH mockup, but this sure could look cool to say the least. Black abs pipe is for visual mock up only, real plenums will likely be hand bent thin stainless sheet. LONG way to go here, but I got a small start back on it in what little time I can spare right now. Nevermind the plumbing connectors, I will be looking into nicer 2 3/8" rubber & clamps.
https://static1.pt-content.com/images/noimg.gif (http://s1094.photobucket.com/user/jlcustomz1/media/20140702_192357_zps8fae2fc1.jpg.html)
https://static1.pt-content.com/images/noimg.gif (http://s1094.photobucket.com/user/jlcustomz1/media/20140702_192129_zps10419604.jpg.html)
https://static1.pt-content.com/images/noimg.gif (http://s1094.photobucket.com/user/jlcustomz1/media/20140702_192144_zps4500ab00.jpg.html)
https://static1.pt-content.com/images/pt/2014/07/20140615_163750_zps7dc91cd6-1.jpg (http://s1094.photobucket.com/user/jlcustomz1/media/20140615_163750_zps7dc91cd6.jpg.html)

[SS PUNISHER]

That looks Badass!

[jlcustomz]

Put a little more shape into the runners & got them fitting better.
Working on design, considering a dual plenum on each side for better air distribution. If I do this , may use round tube up top as in mock up & tapered tubes underneath, which will connect back for single throttle body. See link for what dual plenum per side would look like.https://www.google.com/search?hl=en&site=imghp&tbm=isch&source=hp&biw=1920&bih=959&q=dual+plenum+intakes&oq=dual+plenum+intakes&gs_l=img.12...3533.11439.0.14853.19.19.0.0.0.0.190 .2009.13j6.19.0.chm_loc%2Chmss2%3Dfalse%2Chms2min% 3D10%2Chms2max%3D10%2Chmtb%3D120%2Chmta%3D1440%2Ch mrde%3D0-0%2Chmde%3D1-0%2Chmmpp1%3D1-0%2Chmmpp2%3D1-0%2Chmffs%3D10000...0...1.1.49.img..1.18.1892.usrv zXvTAKU#facrc=_&imgdii=_&imgrc=a_bGKjSFXNfEjM%253A%3Bbns86MwR-JxnHM%3Bhttp%253A%252F%252F1.bp.blogspot.com%252F-VKQqY91Iqqk%252FUqC4uCzvJkI%252FAAAAAAAAAVE%252FMR MiI6yxkIw%252Fs1600%252Fphoto%252B3.JPG%3Bhttp%253 A%252F%252Fthreadheavy.blogspot.com%252F2013%252F1 2%252Fthe-manifold.html%3B700%3B525

Also considering having the round plenum tubes as in mock up have a clear cover on the fronts to view the internal velocity stacks.

[jlcustomz]

Got a little more done after deciding on design. Made velocity stacks & started shaping plenums.
https://static1.pt-content.com/images/pt/2014/08/20140816_201407_zps4d824f76-1.jpg (http://s1094.photobucket.com/user/jlcustomz1/media/20140816_201407_zps4d824f76.jpg.html)
https://static1.pt-content.com/images/noimg.gif (http://s1094.photobucket.com/user/jlcustomz1/media/20140816_201309_zps49dd3838.jpg.html)

[cornfedbill]

Lookin' good!

[jlcustomz]

2 steps backwards now. Started welding up the 20 gauge stainless plenums. Warpage was too much of an issue for me even just spotwelding using pulse settings on my syncro 200. Found out the samples I was playing with were 18 gauge , not 20. I think even a really accomplished welder would have a hard time making this perfect enough for mirror polished stainless, so I'm GIVING UP. Trying to be different has a high learning curve sometimes.

Giving up on 20 gauge stainless for the plenums that is. Could do 18 gauge, but it would be getting a little heavy. Picked up some .090 sheet aluminum # 3003 H/14. Time to start over. Tried a quick tig welding sample of .063 & .125 aluminum after not tig welding sheet aluminum for over a year. MUCH easier. Guess that's one good reason why most other intakes are aluminum & not thin stainless.

Oh well.

[charchri4]

Glad you are not giving up! I have been rooting for you all summer and would love to have the chops to try this myself. It's going to be epic so never give up!

[jlcustomz]

Glad you are not giving up! I have been rooting for you all summer and would love to have the chops to try this myself. It's going to be epic so never give up!

Thanks ,right now I need a little encouraging. trying to see if I have a chance of completing this among other things by October for a gm show. Not easy after being outdoors most of the day in this heat.

I chose to switch to stainless materials for cosmetic & cosmetic maintenance reasons. You aluminum polishers know what I mean. Stainless will shine nearly like chrome & be easy to maintain. If I had started out with aluminum, I could be near done by now. I could still weld up the stainless plenums, but I know I won't be able to get them back straight enough for the mirror polish to look proper.
Also, as far as I know, I'm the first to chop up a nylon intake & connect to it. Hope all that works out.

Working up a new design to use my stainless bellmouths with an aluminum plenum. Making flanges to connect runners to plenum. Will then weld up bellmouths to runners & eliminate the upper rubber connectors. Will look cleaner, similar to an Ozmo intake.

[jlcustomz]

Last view of the stainless plenums, which I am remaking from aluminum.https://static1.pt-content.com/images/pt/2014/08/20140819_210618_zps67ea28c2-1.jpg (http://s1094.photobucket.com/user/jlcustomz1/media/20140819_210618_zps67ea28c2.jpg.html)

[jlcustomz]

Got aluminum plenums mostly shaped. Got flanges cut for attaching runners to plenums to eliminate upper rubber connectors Front pipe on left is where 2 into 1 for throttle body will be located.
https://static1.pt-content.com/images/pt/2014/09/20140907_224400_zps671929c6-1.jpg (http://s1094.photobucket.com/user/jlcustomz1/media/20140907_224400_zps671929c6.jpg.html)

[jlcustomz]

Got the runners tack welded to the velocity stacks, no more upper rubber hoses.
https://static1.pt-content.com/images/pt/2014/09/20140920_172947_zps4f059be9-1.jpg (http://s1094.photobucket.com/user/jlcustomz1/media/20140920_172947_zps4f059be9.jpg.html)
Took back apart for more welding.
https://static1.pt-content.com/images/pt/2014/09/20140921_193936_zpsa503f5ab-1.jpg (http://s1094.photobucket.com/user/jlcustomz1/media/20140921_193936_zpsa503f5ab.jpg.html)

[jlcustomz]

Little more welding & polishing done.
https://static1.pt-content.com/images/pt/2014/09/20140927_185701_zps5219e2dc-1.jpg (http://s1094.photobucket.com/user/jlcustomz1/media/20140927_185701_zps5219e2dc.jpg.html)
https://static1.pt-content.com/images/pt/2014/09/20140927_185806_zps219fce6a-1.jpg (http://s1094.photobucket.com/user/jlcustomz1/media/20140927_185806_zps219fce6a.jpg.html)