It seems a setup of Rover V-8 ITBs from a shop costs ~3000 pounds

"Ramblin Rover - The Vivisector of Solihull" (RamblinRover) 09/07/2013 at 22:10 • Filed to: Racnerho

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So, in general terms, eff that. Two used sets of ITBs for a Honda CBR600 cost <$150, and are 40mm instead of the 45mm that the boutique shop specifies. Total surface area is 40,000mm^2, or roughly 3x the stock single inlet throttle body size, so still muy excelente. A 1.92 square inch inlet makes for sonic flow (and subsequent loss of power) at 427.4 rev/s (16.3ci per inlet per rev., 300 avg. ft/s onset of localized sonic flow) That's... over 25,000rpm. So, perfectly okay then.

!!!error: Indecipherable SUB-paragraph formatting!!! indicates a 29mm throttle body for peak HP at 9000rpm(!) with appropriate numbers for ITBs, so by that metric 40mm is way more than enough as well.

Also, with flexible connectors, Honda ITBs are easier to install to a do-it-yourself manifold. For the price difference, I'll deal with a little tinkering.

BJ > Ramblin Rover - The Vivisector of Solihull 09/07/2013 at 22:20

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I only have a vague idea what you're talking about, but I applaud your creativity. It'll be interesting to see the finished product.

Good luck!

Ramblin Rover - The Vivisector of Solihull > BJ 09/07/2013 at 22:30

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I want to put in my '63 project car a Rover V-8 with a fuel injection system that looks and performs better than a standard '95's EFI system. The point is to have something that looks like a 50s-60s Hilborn-style fuel injection system (pictured), but is practical for daily driving. The post is an examination of using cheap motorcycle parts to git'r'dun, posted for anybody doing tech projects or who might be interested in ITB and fuel injection.

/short version

Frank Grimes > Ramblin Rover - The Vivisector of Solihull 09/07/2013 at 23:13

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I have a hankerin' to instead of put a V8 in my Mustang to mod the 2.3 into a ITB rev junkie. I await.

hollanddjw 1 > Frank Grimes 09/08/2013 at 04:56

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Have fun floating your valves and exploding your bottom end! :P

BJ > Ramblin Rover - The Vivisector of Solihull 09/08/2013 at 10:53

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Sounds like an excellent project. I like the git'r'dun aspect.

Out of curiosity, what makes the pictured setup impractical for daily driving? It's injected, right? Is it a reliability problem? They're awful sexy!

Frank Grimes > hollanddjw 1 09/08/2013 at 12:12

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Maybe i should refer you to the many turbo 2.3 motors running lots of boost with perfectly stable stock bottom ends. Valve float is is just a built in safety feature before things go boom :)

hollanddjw 1 > Frank Grimes 09/08/2013 at 12:36

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Does your 2.3 have that same bottom end? Not familiar with Lima 4bangers.

Ramblin Rover - The Vivisector of Solihull > BJ 09/08/2013 at 15:22

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What makes it impractical for daily driving is that it injects fuel constantly based on engine speed, with what's called a constant displacement pump. However, since an engine's fuel/air mix consumption isn't perfectly tied to engine speed (air compression/pressure differences at the throttle butterfly, different evaporation of fuel based on temp), it only operates very well at high revs. At mid revs, it can end up running too rich, and at low revs or when cold, it can have trouble having enough fuel to run.

Various fixes have been come up with, including fuel flow controls operated by vacuum, extra pump stages, and the ability to tweak on the fly. Still, it often doesn't temp-adapt that well, and usually has some efficiency issues. Worse, bespoke Hilborn systems customized for an engine are crazy expensive. Hilborn makes their own EFI systems of a Hilborn style, but they're expensive as well.

I'm sidestepping this; since I have all the sensors/etc. of a full modern EFI system for my engine on hand, all I need is to set up the right injection and throttle body setup, connect to a Megasquirt or equivalent fuel injection computer, and I'm set. Grand Prix/ hot rod-looking stacks without the drawbacks, with the benefits, and cheap to boot.