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I had to remove my plenums to chase down a coolant leak. Now they were a right mungral to assemble and even worse to disassemble, so I’ve been working on ‘plenum mk2’, a; to shorten the length from throttle plate to inlet valve and b; to make fuel fittings and injectors more accessible and c; to use smaller throttle bodies. I first fitted 2 x 74mm Bosch ETBs but they were too big even for 6.5 litres. very touchy trying to use light throttle and this is just in my workshop and unstable revs above idle. The slightest touch on the throttle and it shot up to 4000rpm. I've now gone for 2 x 60mm Bosch ETBs, much nicer.
I ended up with 2 manifold mounting plates, first one bolts onto the 87-95 manifold bottom bolts, behind the fuel rail while they are accessible. The second one has it’s own bottom bolts, tapped into the first plate, so they are accessible above the fuel rail and under the plenum. The rest of the bolts go into the stock manifold threads. I’m using Bosch EV14 ¾ length injectors otherwise none of this would fit. first assembly plenum mk2 Mock up test fit tack welded ready for final TIG TIGed up first air intake attempt first start up with 2 x 60mm ETBs
06-29-2024, 12:43 AM
