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I have had the belief that the stock manifold was not made for performance and is less than ideal. I have occasionally thought it would be cool to make my own and see if I am right or wrong, recently I have decided to commit to actually follow through and see what I could do. I have nearly finalized a model that I want to try, this thread will be dedicated to this process.
About two weeks ago I completely restarted the model with design elements specifically revolving around being able to be manufactured as well as fitment in the engine bay. My first model turned out to add complexity and unnecessary hurdles to make, the second was too tall to fit under the hood. I have goals of fitting inside the space occupied by the oem manifold and engine cover. I am currently just slightly taller than the engine cover, I don't have measurements for hood clearance but I think it will fit.
Areas of improvement I have seen for the stock manifold have mostly been addressed with some minor compromise. I wanted to tailor this manifold to make more power up top. I have increased plenum volume, made accommodations for running a 76mm throttle body and have designed the manifold around having swappable velocity stacks to dial it in for a desired RPM range. I initially wanted to keep the runners as straight as possible while maintaining minimal change in the cross section shape but that resulted in a manifold that was too tall. The manifold will be tested against my oem manifold which has been lightly ported and modified to accept a 76mm throttle body. A current good peak maf value with my entire intake arrangement is ~260-265g/s, ill get around to making a nice graph at some point but my goal with the new manifold is to hit 275g/s. I don't know how much to expect for improvements, I will be quite happy to see an equivalent of a 10HP+ gain up top and feel that if my execution is adequate that this is reasonable.
Currently I am just a few measurements away from being able to place vacuum ports where they need to go and finalize some velocity stack options and I will have a proper finished model. I also need to investigate the wiring harness to see if the stock one can be used with the new throttle body location without modification or an extension.
This is an interesting project and I hope you figure out all of hurdles with making this design work on the 2GR-FSE. If anything, the induction sound will be phenomenal.
Right as I was happy with my model I decided I could do better. I am getting a 3d scanner to scan my engine bay to guarantee fitment. I am going to rework the plenum again so that it is aligned properly to use with the stock airbox. My OCD on this is really escalating and I am wanting this to turn out as well as possible.
As for reworking the airbox and factory scoop thing. I currently run an open filter as it flows better than the stock air box and while running e85 I'm not particularly worried about IATs. Making a new lid for the stock airbox is something I am considering but I don't plan on making a new scoop. Making a lid with swappable inserts sized to play with maf readings to allow me to switch in and out of e85 without reflashing my ecu has been something I have wanted to do, I might do this after the manifold is good.
As of now I am not able to make manifolds as I am again waiting on necessary parts. I am making a large 3d printer designed around printing with a higher end filament and the requirements for this are a good notch above hobby level printers. My main problem is working around the temperature requirements. Having an enclosed heated chamber of 150-165F means I am dealing with thermal expansion of different materials, including the frame itself and there is a bit to keep in mind and design around with this. I believe I am close to having the bulk of these issues resolved, I should know and have initial test prints to begin necessary calibrations within a couple weeks.
I have had the belief that the stock manifold was not made for performance and is less than ideal. I have occasionally thought it would be cool to make my own and see if I am right or wrong, recently I have decided to commit to actually follow through and see what I could do. I have nearly finalized a model that I want to try, this thread will be dedicated to this process.
About two weeks ago I completely restarted the model with design elements specifically revolving around being able to be manufactured as well as fitment in the engine bay. My first model turned out to add complexity and unnecessary hurdles to make, the second was too tall to fit under the hood. I have goals of fitting inside the space occupied by the oem manifold and engine cover. I am currently just slightly taller than the engine cover, I don't have measurements for hood clearance but I think it will fit.
Areas of improvement I have seen for the stock manifold have mostly been addressed with some minor compromise. I wanted to tailor this manifold to make more power up top. I have increased plenum volume, made accommodations for running a 76mm throttle body and have designed the manifold around having swappable velocity stacks to dial it in for a desired RPM range. I initially wanted to keep the runners as straight as possible while maintaining minimal change in the cross section shape but that resulted in a manifold that was too tall. The manifold will be tested against my oem manifold which has been lightly ported and modified to accept a 76mm throttle body. A current good peak maf value with my entire intake arrangement is ~260-265g/s, ill get around to making a nice graph at some point but my goal with the new manifold is to hit 275g/s. I don't know how much to expect for improvements, I will be quite happy to see an equivalent of a 10HP+ gain up top and feel that if my execution is adequate that this is reasonable.
Currently I am just a few measurements away from being able to place vacuum ports where they need to go and finalize some velocity stack options and I will have a proper finished model. I also need to investigate the wiring harness to see if the stock one can be used with the new throttle body location without modification or an extension.
Good job on creating this model. Your design methodology is solid and you are certainly doing a great job at taking all the important factors into account during this process.
I am definitely curious as to how this turns out and I am gonna stay tuned! Keep up the good work, DickH!!!!
@DickH Any update on these? I want one if you get them done.
I stripped the printer down to completely redesign it to be more focused on manufacturing. Unfortunately this is a huge last minute change and I have been busy with other things to really spend time on the printer. This manifold and printer are kind of a side project for me so they sit low in priority until I have the extra spare time. Fortunately I have spent way too much money on this endeavor so I have to finish. I'll definitely keep the few that reached out to me in mind once I am able to reliably make these manifolds. That's the other catch, I will be hesitant to sell until I am comfortable with the end result.
Intake Manifold Project
