crossflow on throttle bodies
Posted 01 June 2010 - 03:32 PM
Posted 01 June 2010 - 09:26 PM
Hardest part without doubt is making the inlet manifold. Mine had to go from a circular shape of the Yam TB to a kidney-shaped port of the Zetec SE. I started to fab something, realised that it was way beyond my skill level and immediately entrusted the whole task to Nigel at Altiss Engineering, who I can't recommend highly enough. He then fabricated a beautiful inlet manifold out of TIG-welded alloy (work of art it really is).
I then used the injectors on the Ford engine, and the injectors on the bike to fuel it (the Emerald brings them in progressively above a certain rev range). Fuel pressure reg is from the original bike.
I use a combination of pumps. Firstly a low pressure high volume Weber type unit mounted in the front to suck up fuel and keep the swirl pot topped up. This swirl pot then feeds a high-pressure Bosch car fuel pump to pressurise the fuel rail (s) via its lowest outlet (SBD do a good swirl pot plumbing diagram). The upper-most hose on the swirl pot is then returned to the fuel tank. I did this on my specific car as it uses an MG midget carb tank and had lots of problems with fuel starvation.
With a Westie, they do quite a nice fuel tank with a built-in swirl pot and one high-pressure fuel pump mounted low down - that's probably the easiest route to go for you and would avoid the need for
Finally I got the whole thing running roughly (following the Emerald instructions) and then took the car to Dave Walker at Emerald to get it set up properly. Unless you're an electronics genius it's virtually impossible to get the car mapped as well as a pro. After fitting cams to this otherwise stock engine I got 160bhp on the rollers (100bhp from Ford).
The key bits, I think, are to get a decent inlet manifold made up (yes, you can get slightly cheaper steel ones made, but they're not a patch on a custom alloy one) and to choose a TB set up that is roughly spaced like your cylinders if possible - saves a lot of mucking about messing up the TB linkages and having to fabricate fuel rails. Jenveys are probably one of the best.
Chatting to Dave Walker he reckons the diameter of the TBs is nowhere near as critical as carbs, which gives you lots of options. I'd read loads of rubbish about my Yam R1 TBs being too large for my engine and lots of nonsense about 'poor low speed air flow', but in the real world they've been fine - pulls cleanly from 2K revs, gets into its stride at 3K and then howls round to 8K - nice!
Also get it set up on a rolling road - best £200ish you'll spend and will saves months of guesswork.
With the ECU, TB, inlet manifold fabrication and rolling road set-up, I got the whole thing running for around £1000 ish.
Posted 02 June 2010 - 06:53 AM
Posted 02 June 2010 - 07:29 AM
Posted 02 June 2010 - 07:51 AM
Must be a heck of a crossflow to run on 48's! However does that mean you can put 45 t'bodies on the same manifold?
Have a read here:
It's not a crossflow but Ian's explanation of how to do things is very good and clear.
Posted 02 June 2010 - 09:11 AM
I put a seperate pot in, with a lift pump, and the resulting hornets net of plumbing and wiring looks a right mess, then just to add insult to injury Chaz found somebody who can put a nice big 1 litre swirl pot on to the bottom of the tank with an integral pre filter for not much more than I paid for the external tank.
Posted 02 June 2010 - 09:43 AM
Posted 02 June 2010 - 01:55 PM
You would need a restrictor in the feed from the lift pump to the swirl pot to prevent the lift pump running flat out. The return feed from the pressure regulator back to the tank is at atmospheric pressure or whatever pressure is left. It won't be much...
Best place for a swirl bowl is dead centre of the fuel tank bottom face. Cut a 2" (5cm) hole in the base of the tank. Turn down the edges so that they are proud on the *outside* of the tank. This gives you a vestigial "baffle". Then weld the swirl pot over the hole, and add a -6 fuel line connector. That's what I've done on mine. The swirl bowl itself is a good 6" (15cm) in diameter. I forget the depth
I also added a return to the top of the tank right above where the swirl bowl is. Mods, including 3 off -6 fittings (feed, return and breather which is out of sight) cost less than a lift pump and swirl pot to buy...
Posted 02 June 2010 - 02:11 PM
I've always wanted one of those !!
This gives you a vestigial baffle.
Posted 02 June 2010 - 09:55 PM
One more thing.....45's or 48's ?
Posted 03 June 2010 - 05:53 AM
Posted 03 June 2010 - 02:27 PM
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