RJM GTR Intake Lower Manifold...oh yes!

Alstann

Woah guys! This has blown up since I last checked it out, haha.

Firstly, I'm planning to install it later this week or next week, I want to run my custom return fuel setup with this, so I need some more time to get that together. Planning on buying an Aeromotive FPR and running a return under parallel the OEM lines, and back to the tank, set it to stock FP, and let her run. To be honest, work has been getting very busy, so it may be a while before I have time to really crack at it and get a dyno day together.

Whilst I think there is definitely gonna be an argument with smoothness of the runners, my first comment will be that it is smooth to the touch, and definitely way less rough than a cast manifold. I purposely chose very harsh lighting to show the end-milling, and it is more than acceptable for a manifold, or any intake part.

Secondly, whilst I don't claim to be a race engineer or anything of the sort, I am professionally a MechE and also did analysis for intakes for Formula SAE. If you wanna talk about flow patterns here, the flow on the surface layer of any tubing in a closed environment is zero. This is simple fluid mechanics, and the velocity increases non-linearly to it's fastest point, which is in the center of the runner.

What this means is that surface roughness, to a degree, has negligible effect on air turbulence and velocity. If you ask old V8 guys in the business, they'll all tell you that polishing a manifold to a mirror shine is little more than a "feel-good" mod. The main contributors to power and flow are the runner shape and diameter. Minor losses will always exist, and anyone who tries to chase perfection will spend thousands of dollars doing it, for diminishing returns.

Speaking of manufacturing methods - machine time is VERY expensive. My experience in creating pure CNC parts that have complex paths and require lots of machine time - things like this are hilariously cheap. And don't even get started on casting - that will be a heartache when you learn how much master molds cost to create.

I don't want to address any personal feelings on this thread - just wanted to share what I think is a fantastic part. Bobby and RJM delivered to me a fantastic product, and I have no complaints. I knew exactly what I was purchasing since the inception of the part, and I'm happy to have one. I think that everyone should be happy parts are being developed for the platform!

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