As a cheap test it'd be interesting to see the dyno of a 1UZ with the stock lower manifold and 8 bike throttles slapped on it.
Hopefully, not much low end torque would be lost due to keeping the crossover configuration, and the 8 butterflies should open up the top end a bit?
With 8 x 40mm butterflies, there would now be 8 x 1257 = 10053 mm2 throttle area, instead of 1 x 3850 = 3850mm2 area for the single 70mm OEM butterfly and a restrictive MAF.
Interestingly, losing the plenum apparently hurts an ITB setup for the street. I don't claim to be a fluid mechanics expert, but I know that both sides of the engine benefit from pulse tuning, not just the exhaust, and the plenum is nothing more than a tuned chamber designed to do that. That's why BMW actually lost HP with their straight ITB setup until they restored the air chambers/plenums upstream (before) the butterflies. So now, on nearly all production engine setups (Ferrari, BMW, Lambo, etc.) with ITB's, you see a plenum on each bank before them. Sorta takes away from the bling of the ITB's but they work better.
I think it would be interesting to compare dynos of these cheapie ITB's on the 1UZ when they're sitting in a vertical configuration, and then in a horizontal one (similar to the old Kinsler CanAm setups), which would extend the crossover concept even further. Here's a shot of Kinsler's new crossram ITB setup in carbon for the chebbie LS motors:
Hopefully, not much low end torque would be lost due to keeping the crossover configuration, and the 8 butterflies should open up the top end a bit?
With 8 x 40mm butterflies, there would now be 8 x 1257 = 10053 mm2 throttle area, instead of 1 x 3850 = 3850mm2 area for the single 70mm OEM butterfly and a restrictive MAF.
Interestingly, losing the plenum apparently hurts an ITB setup for the street. I don't claim to be a fluid mechanics expert, but I know that both sides of the engine benefit from pulse tuning, not just the exhaust, and the plenum is nothing more than a tuned chamber designed to do that. That's why BMW actually lost HP with their straight ITB setup until they restored the air chambers/plenums upstream (before) the butterflies. So now, on nearly all production engine setups (Ferrari, BMW, Lambo, etc.) with ITB's, you see a plenum on each bank before them. Sorta takes away from the bling of the ITB's but they work better.
I think it would be interesting to compare dynos of these cheapie ITB's on the 1UZ when they're sitting in a vertical configuration, and then in a horizontal one (similar to the old Kinsler CanAm setups), which would extend the crossover concept even further. Here's a shot of Kinsler's new crossram ITB setup in carbon for the chebbie LS motors:
![LS7XRamClpwebs.jpg](http://www.kinsler.com/NewProducts/Pics/JPG/LS7XRamClpwebs.jpg)