Aftermarket Plenums
A few people were interested in front facing plenums for various reasons such as neatness, decrease in cooler piping length and so on, so here are a few plenums.
1. RIPS plenum I really like the look of these plenums and the fact that it contains ALL the factory sensors. RIPS, who are based in NZ, use one on their RB30DET R32 that runs 10's Design- GT-R style, tapers towards the rear cylinders to help pressuirise the plenum and to even the flow distribution so not as to lean out cylinders 5 & 6. It utilises short runners which will suit high RPM, but you will probably loose some low end torque. I believe RIPS sell them in kit form to suit any RB head for ~$1350 AUD which includes plenum (painted in your choice of color, modified throttle cable braket, and modified throttle cable)
2. Thailand Special This plenum has the same look and style as the RIPS plenum and the previous information would follow on here. Design looks nice and round, which is good for pressurised containers, No sharper corners/welds means there are no weak pressure points, thickness and quality of the welds would be useful to know. Does not look like all the factory sensors bolt up onto this item, such as AAC valve. Although this item could possibly be cheaper than the RIPS item, it lacks the factory sensors, quality and workmanship is unknown, previous/current cars using this plenum and their power outputs/boost pressures would be good to see.
3. Greddy Mass produced and well known product. Works well, has been tried and tested both locally and in the japanese market. WIll no doubt be the most expensive of the lot. Construction is SOLID cast alloy. Direct bolt on item, not sure if all the factory sensors bolt on at this stage, but i dont think they all do. Comes ready to suit a Q45(or is the VH45) throttle body, requires an adapter to fit the stock throttle body. Will only fit RB25, or RB26, depending which one is purchased. Short runner design, better for high RPM
4. Cut and Shut This mod does not cost much at all in relation to the rest of the front facing plenums. Problems that can arise from this mod is that these plenums have been engineered to work best with side feed. People have had cylinders 5 and 6 lean out due to receiving too much air. Lots of people produce the numbers with this mod, but myself i have never heard of any long term success stories Involves removing the stock throttle body, welding a plate over stock position, welding throttle body onto 'front' of plenum
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V8_dave