proxlamus©

http://forums.hybridz.org/showthread.php?t=128284 I did a write up and grouped all the pictures together in an easy to read single page lol

For my final project for Advanced Welding, I decided to built an intake manifold out of 6061 aluminum for my old Datsun 280z. I originally planned a individual throttle body project, gathering 6 throttle bodies from a Suzuki GSXR 600. I also planned on building a plenum to support my turbocharged application. The goal was for an all aluminum intake manifold, with a ¾†thick aluminum intake flange, ¼†I.D. aluminum pipe and 6 throttle bodies attached by a silicone or fuel rated rubber hose couplers. This manifold would be attached to a 4†diameter aluminum plenum with 2†velocity stacks with a 2.5†wide bell mouth also attached to the throttle bodies with rated couplers. On paper the project seemed easy, but with every project careful planning was necessary and developed into a harder project then I had imagined. The first steps in fabricating this manifold required a careful selection of materials, measurements, welding technique and the goal to minimize cost. Welding up runners to a flange for an engine isn’t as simple as cutting a pipe and welding on a throttle body. In a reciprocating engine the intake and exhaust valves are constantly opening and closing. The speed in which the valves open, lift and duration depends on the camshaft design, valve design and engine revolution. As the intake valve opens, the piston sucks air into the cylinder during the induction stroke. Eventually the intake valve closes to allow for combustion of the mixture. The problem lies within the pressure waves created by the closure of the intake valve. When the fast moving air slams into the now closed valve, the air will continue in motion and begin to compress. Now that the air is being compressed the air has nowhere to go. Newton’s First law of motion indicates an object in motion will continue to stay in motion unless an external force is acted upon. Newton’s Third law of motion is for every reaction there is an equal and opposite reaction. This intake wave will revert back down the runner, commonly called a “pulse wave.†Ideally for optimum performance, allowing the pulse wave to bounce back down the runner and enter the cylinder as the intake valve opens will create a supercharger effect. In order to properly time this intake pulse the length of the runner is important, including inside diameter and taper of the runner. The speed in which these pulse waves travel also varies on the speed of sound, which varies with air temperature, density, humidity and altitude. I was able to find a handy dandy calculator online to provide calculations based off my tube inside diameter, camshaft duration, and peak torque range for my desired RPM. These measurements were for standard conditions at sea level. Now this measurement is not the length of the runner, rather the length from the throttle body or plenum to the center of the intake valve. I was able to calculate with my camshaft duration of 260 degrees and an inside diameter of 1.4†and desired peak torque at 5,350 RPM my runners should be 63†inches long. Ideally this would not work due to space restrictions, so the next best option is to use one of the multiple pulse waves reverted back and forth. My final calculations were 11.2†from the center of the intake valve to the throttle body. This would allow me to take advantage of every 5th intake pulse. For my parts selection I chose 6061 aluminum which is very light and can be easily welded and cut. I purchased the intake flange from a local member of a car forum I am a member of and began my project. In order to properly weld the aluminum, I needed a TIG machine which is capable of AC or DC current, which I would take advantage of the AC for aluminum. When welding aluminum I would manually select AC current and I adjust the AC wave balance, current in amperage and frequency. The total current adjusted the amount of heat I applied into the material. The AC wave balance adjusts how much the positive or negative waves on the sinusoid wave are applied into the material. Basically the lower the balance value, the less cleaning the arc will provide and deeper penetration into the metal. The greater the balance, the more cleaning is provided but you lose penetration. I chose a 75% balance which is a very nice balance for welding aluminum. Finally the frequency adjusts how wide the arc is on the metal. For a nice wide arc and puddle a low frequency is ideal. The lower the frequency the less penetration I will gain. Increasing the penetration narrows the arc. The narrower the arc, the more focused the heat is, which allows greater penetration. Proper gas and tungsten are also important. For this application I used 100% argon and Zirconiated tungsten. For cutting the aluminum, I was fortunate enough to use several tools throughout the shop including; a band saw, 14†chop saw with an aluminum rated blade and a plasma cutter. Once everything was cut to my specifications, I was careful to de burr the material and begin the materials for welding. The key to a strong weld with deep penetration and a clean bead is cleanliness. I cleaned the ends of the aluminum with emery cloth, then a stainless steel wire brush and rubbed the aluminum down with acetone to clean off oils and grease. To prevent warping the aluminum flange I clamped the material onto a sturdy welding table with a steel surface to help absorb the heat. The first step was tack welding the runners to the flange to ensure a proper mock up. It is important to add several tack welds around the runner to prevent warping. Once everything was tacked onto the flange, I ran a full fillet bead around the runner onto the flange. This was difficult to do in one continuous run, so I was able to do each runner in 4 sections. My biggest difficulty was between cylinders 1 and 2, as well as 5 and 6. Due to the close proximity of the runners there was a tight gap I needed to weld in. I attempted to use a very small cup and extended the tungsten out to fit the gap, but continued to see a muddy, dirty puddle. This was one of my first errors when welding the project, due to the high air pressure being accelerated out of the smaller cup. My welding instructor mentioned I should lower the air pressure to help out the situation. Unfortunately the gap I was trying to work with was too small and I was unable to get adequate gas coverage. The only option was to apply a lot of heat and filler metal to melt out the impurities in the metal. I would then apply a die grinder to grind out the impurities and apply some more filler metal and heat. Eventually there was clean aluminum grinded down smoothly without pitting or cracks. After welding each runner to the flange I allowed proper cooling to prevent warping or running too much heat on the next runner which could create a uncontrollable weld. Now that the flange and runners were completed, I temporarily mounted the throttle bodies and came into my second issue of the project. The famous rule, measure twice, cut once should have been followed here. After mounting the manifold in my engine bay I realized I cut my runners too long and did not allow for proper clearance for my plenum. In order to fix this I decided to flip the plenum on top of the throttle bodies and runners and utilize a 180* degree bend. In addition to running out of room, I also already cut the materials for the plenum design which meant I had a 4†diameter pipe now in half horizontally so I did not have a sealed tube. I was able to fix this by re-attaching the 2 half pieces of aluminum and running a full weld down the manifold which wasn’t fairly difficult. I used a square butt joint weld for this application. The next step in welding up this project is cutting the holes for the velocity stacks on the plenum and welding them on. I carefully measured the proper spacing for the velocity stacks to line up with the throttle bodies and used a 2†hole saw on a mill and cut the holes. I was able to insert the velocity stacks from the inside of the pipe and push the attaching end out of the plenum and run tack welds. I learned that polished aluminum is fairly easy to weld once being cleaned properly. I used a fillet weld technique all the way around the velocity stack and plenum. I also extended the length of the plenum by adding a 4†long section of tubing to the end of my plenum using a square butt joint weld. Overall the project was very difficult due to time constrictions, price and selection of materials, inadequate planning and improper measurements. Fortunately I was successfully able to weld an intake manifold to my specifications and should show an improvement in my engines performance and tuning. Although my poor planning was the primary difficulty, the welding process and instruction by my teacher was extremely beneficial and proved to be much easier than I expected when following procedure and processes. Anyway.. here are some pics of the project This above was the original plan. Unfortunately because i did not plan this well enough, I was unable to use this beautiful intake design. In the end I was able to use a larger plenum design by flipping the plenum on top of the manifold, similar to a Nissan Maxima intake manifold on the LD28 motor. Yes the rubber hose is ugly... but I am sourcing down a cheaper option than $210 for 6 - 2" u bends! Give me some time!!

if you look back to the first post I made.. i wrote what i would be using =) Suzuki GSXR 600 throttle bodies

Do you guys see any problems with using 180 degree Stainless or Aluminized steel for these bends?! It would be much cheaper then aluminum.. soooo much cheaper

I would like to do a base dyno run.. then install the new manifold.. and do another run just for kicks. TeamNissan.. what do you mean by TBS? do you mean TPS (throttle position sensor)? If so I am using the 240sx tps, or using the stock TPS on the GSXR throttle bodies.. and I will match it up with megasquirt... hopefully

no the calculator I used was based on a standard temp... (59* F 29.92 in. hg) here are some more pics of the manifold! I found those hoses for a total of $70 for all 6 cylinders! MUCH cheaper then I had planned. Yes its ugly and definitely detracts from visual aesthetics =( kinda bummed about that.. but if I want it pretty I have to spend $210 on aluminum u-bends.

the velocity stacks came from Blue Grass Muffler Dave.. your 100% correct... My aircraft performance class intensely covered the speed of sound and change in the speed with altitude, density and temperature. =)

it is possible to tune each cylinder w a very sophisticated FMS and individual EGT probes after EACH cylinder... much like high performance aircraft use. The stock RB26 runners and throttle bodies will handle 1000 hp plus... so I have no doubt that my manifold will be plenty for my 400rwhp motor LoL I also found out that NISMO's new RB plenum did NOT have a velocity stack/air horn on the 6th cylinder.. why ... im not quite sure. In addition the available volume of air decreased as it was closer to Cylinder 6.

huh? whatcha mean $$$ ? I will be using the fuel rail I have on the Z now.. which was manufactured from Pallnet.

well the first improvement over stock is the larger diameter runners.. which will remove the restrictions of the stock intake.. which begins to run out of room for air after 5,000 rpm. in addition my longer runners will provide a slightly more torque at lower RPM's. with 6 throttle bodies... throttle response increases dramatically For more info visit this link : http://www.autospeed.com/cms/A_3049/article.html

I kno about Ross Machining.. I began pricing my manifold through them.. but I found some parts for MUCH MUCH MUCH cheaper than any online company offered the materials. Trumpet.. your right.. Cyl 1 and 2 will have the most air.. and 6 will get the least. unfortunately with my space restrictions I was unable to design the plenum I had originally planned, which would angle the air to the center of the manifold so all cylinders will get equal air (Look at Ron Tyler's beautiful manifold) However.. its proven with RB's, L-series motors, and 2JZ's etc can produce loads of power with the similar plenum design like I have.

The last picture shows how the manifold will be pieced together.. using a 180 degree 2" ID radiator hose.. cheap and ghetto i know.. but it works!

take a small spring.. about the same ID .. and twist it in like a screw.. it will hold its form .. but you mentioned that CarQuest/Napa also sells a spring that goes on the outside which is kinda cool.. and apparently it applies even pressure all around so it wont collapse

I ran a ford taurus fan for a long long time on my z as a pusher.. never again. im doing it right and bought a lovely fan from TimZ =) and its soooooo much better... easier to install.. no trim work... perfect sealing.. and a puller

Tony would you recommend a 2x4 plenum?! The intake I am building I decided against a 2x4 plenum because i assumed it was way way way too small. For a boosted engine the intake volume should be 1.5 times the total engine displacement. Maybe i'll build a spare 2x4 plenum during my welding class tomarrow for kicks, I could always sell it =)

Radiator is stock my intercooler is a Isuzu NPR intercooler.. so I want to say 2-2.5" thick i believe

I already welded the runners to the flange. I am going to weld in the velocity stacks in a few hours to my 4" plenum. I found an awesome 2" I.D. 180 degree fuel filler hose for $15 a piece at CarQuest!! So I can either utilize 6 - 180 bends or I can cut each piece in half and make 2 - 90 bends out of each one. MUCH cheaper then the $35 a piece silicone or aluminum u-bend. Cheapest option I found was $7 ...90 degree elbows in aluminum from Global Tech Engineering recommended from Austin.. I would buy those then a silicone coupler which is about the same price as the full u-bend itself! yes fuel filler hose is UGLY... i would prefer aluminum. but damn this manifold is getting pricey lol. $156 for 2 sets of throttle bodies shipped $80 for the aluminum sheet, 4" aluminum pipe, 1.625" runners $135 for the intake flange shipped $116 for the aluminum velocity stacks shipped Soo total is $487.. which is a bit pricey (im thinking lonewolf's intake now lol) .. and then I need possibly an additional $100 in rubber couplers/bends. Still cheaper then having a shop weld up one.. or buying other ITB setups.. and I have my own plenum for the turbo and experience gained!

LoL Evan.. I am NOT using a Nissan Maxima Diesal intake manifold... I will have a very similar design to the Diesal intake. I will be using my own flange, runners, and throttle bodies for this project. In order for my plenum to fit my manifold.. I need to flip the plenum ontop of the runners... just like the Maxima Diesal design.

im sorry guys.. Ok .. I decided to build a Nissan Maxima Diesal style intake due to my space restrictions.. Which looks like that above. So what I am deciding to do is use my straight runners and throttle bodies, then flip the runners around and use my 4" plenum =)

Ok.. im trying to figure out the best way to use 180 degree curved runners.. I am debating between silicone and aluminum.. a 180 degree bent 2" o.d. aluminum pipe is $35 a pop! and I need 6 of them! ugh! http://www.fortune3.com/Slomo/180_Degree_Bends-Vibrant_2_O_D_Aluminum_U_Bend_Polished_1.html another option is a 180 degree silicone elbow which is also around $35 .. Soo thats another $200 for this project and this design! UGH! Any other suggestions?!

dude.. how freakn similar are our cars?! jeesh man. I have a 260 duration cam and .488/.488 lift. man oh man

Well.. I've had ONE month to work on this with limited time and money lol. Soo.. im a nervous wreck.. this has to be done by saturday.. ive already invested too much money into this lol.

Im all over the place.. i decided to scrap the crappy box plenum.. use a 4" round pipe which I welded back together.. and make a setup similar to the Maxima Diesal intake.. yeh there wil be a bend but who gives a hoot

Well.. I spent $20 on a 5 foot length of 4" tubing... for some stupid reason. and already cut the piping and had it set up for the plenum I wanted. Then I measured it all and realized i made a big big boo boo Id prefer not to buy more materials.. I will just weld up my own square plenum. =(

alright... im going w a 3x4 plenum. dont have much of a choice =(