Buztoy,

Do it blow through with a metro turbo SU, trust me any other way will not easily work.

SPI is crap

Twin-point won't beat carby on anything with decent power, even with big injectors the rpm won't be achievable and if you think a turbo will work, forget it.

Daniel

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Videos - Turbocharged A-Series on Dyno & at Wakefield
Mafs waz not my strong subgeckt at skkol

i hate SU, the one i had on my motor i could rev once or twice and that made my celica sound like a proper idle, brap brap brap brap brap. every since then i have never liked em

doz what about blow through webber or dello

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You can put blow through weber/dellorto, but where you going to put it? I reckon you should go to the Dyno day at MRC on the 5th of May and have a look at ben's turbo 1100 for an idea and chat to Grant about the SU.

Daniel

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Videos - Turbocharged A-Series on Dyno & at Wakefield
Mafs waz not my strong subgeckt at skkol

yeah i probally am going, but i know both use SU, i know there is a bloke on here who did a S/charged webber,

the bloke who i spoke to also said that if i go suck through it will atomise the air and fuel making a more exsplosive mixture and can run on less fuel, problem was i was talking to my g/f (studying chemistry 4th year) about this same fact/ theory and she says that it would do a opposite effect,

the point that the bloke made about webber and dello not like to be forced is the butterflies open up and clean out what fuel i have in the throat which can make it splutter or stall, so i need a huge carb, 48- 51 ML, by using the extra large carby i wont get the optimum CFM i need, like sticking a 650 holly on an 850.

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hehe 650 on an 850.. that would be funny

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A suck through turbo application needs turbulence in the manifold to mix the fuel/air as the fuel is thrown out of the air by the centrifuge effect of the compressor wheel. Blow through is better in this regard. Also compressing the mixture adds heat and evaporates more fuel. Evaporated fuel doesn’t burn so does not contribute to power (less economy).

The other problem is when the air/fuel is mixed prior to the turbo it becomes explosive; a backfire could well damage the compressor.

Not to say a suck-through won’t work, I’ve seen plenty that do, I just reckon a blow through is worth the effort and I doubt you would get a weber/dellorto to fit comfortably compared to an SU. The lotus Esprit had twin dellortos with a blow through non-intercooled set-up till about 1989, you should google these to see how it works on them.

Your comments about the carby not being big enough doesn't make sense. The accelerator pump on both the weber and dellorto sprays plenty of fuel, it's got nothing to do with throat size. A 45mm weber will support double the HP you're looking at easily.

Daniel

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Videos - Turbocharged A-Series on Dyno & at Wakefield
Mafs waz not my strong subgeckt at skkol

what dirty minds we have.

what he was saying is that the accelarator pump isnt big enough i would, i've seen how powerful the pump is, the carby im running now i can squit fuel a third the length of the car with a flick of the butterflies but apparently this isnt enough, im running a 42ml, i take it appart and you see a small tank for the fuel which would hold similar to 42ml, now i cant see how that thing could empty out in such a short time,

doz, will i see you at the dyno challenge

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any parts for a 76 clubby pm me or ring 0405 329 326

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sorry did nt answer this one but because the engine will be forced, manifold dont have to be as straight so i was thinking maybe i could use a gooseneck mani,

either way i reckon i can build a small horn shape to go over the front of the carb

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HALTECH E8

if you want to do it properly

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Miniworx Centre 0883741299
Sooperdooperminicooperexpertengineering
Online BMW Mini Shop

Haltechs are fun

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whats that, computer?
http://cgi.ebay.com.au/EFI-Hardware-Thr ... dZViewItem
i dont get why i cant use these, with a different manifold of course, they have a similar throat size, just the fact that it has primary ijectors and secondary injectors, now could nt i use smaller injectors,

like the doc said offset the firing order 1 behind its self, 2 and 1 fire straight after each other so why could nt i make the injectors the same and run some sort of 4cyl computer, the primary injector will open and cyl 2 suck it through then secondary injector will open and cyl 1 will suck it through,

with the SPI, MPI,ECT minis, do they use a crank angle sensor or similar

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thats what I am thinking about with gas injection on my mini. but your manifold ends before its split into two ports so you would probably have a fairly "unstable" setup with the pulse for #1 being in the way of the pulse for #2. to get it smooth I imagine you would have to inject a smaller amount for #2 than for #1... It might be minuscule enough to ignore though... but then why not pulse one injector twice

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yes, the injection engines uses a crank angle sensor, a reluctor ring fitted to the flywheel and the sensor in the bellhousing

pulsing one injector twice is done with the MPI setup from rover, you have to use big injectors as each puls is very small to inject the right amount of fuel

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Rover 214 atm ....

I have a sidedraft carb car making 120hp with no injectors....

My point is, is it worth it in the end when you can achieve massive figures from relatively cheap, simple setups? I am not doubting you can probably make SPI/MPI go very hard and it probably idles and runs better as well....

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Lillee - 1969 Morris Mini K

The issue of the shared ports is that they have an overlap between the open inlet valves.

So, number 3 inlet valve opens and hasn't yet shut when number 4 opens. If your injectors pulse open in the first half of the inlet cycle, then number 3 will rob some of the fuel intended for number 4. Result: 2 & 3 run rich and 1 & 4 run lean.

In theory there are two cures:
1) make the fuel/air mix as homogenous as possible, like a carburettor. This can be achieved by an injector with very long pulse width spaced a long way from the port plus some turbulence. SPi works like this. There is a large single injector, no cam angle sensor and the inlet manifold has some lumps on it at the manifold face to direct the flow preferrentially to the correct cylinders. Unfortunatly the small injector working hard doesn't leave much room for upping power, putting in a cam with more duration makes the problem worse, the throttle butterfly isn't very big and the manifold has some sharp bends and the lumps which decrease it's flow ability.

2) use sequential injection to pulse the fuel in at times when there is no inlet valve overlap. This means large injectors, short pulse width, close to port injection and a sequential injection computer with individual cylinder pulse timing. MPi works a lot like this and has a cam angle sensor so it can be properly sequential. It also has a few manifold tricks to help the fuel get spread correctly. The MPi system is restricted by a throttle set-up that doesn't allow the butterfly to open all the way. More power can be extracted by a simple throttle body swap. See Mini magazines for adverts for these. More power is available from these but the tuner needs to know what he's doing or it will be no good.

Either way there are difficulties and compromises.

Don't believe rubbish explanations like "the head is too restrictive, that's why a carb works better..." The head is the same EFI or carb.

If you want multi-point EFI on a 5 port head you must have a sequential injection computer. This will require a cam angle sensor, crank only is not enough. You will be best off having two o2 sensors or at least two exhaust gas temp sensors to tune the thing and you'd better get a computer that can trim for injector opening delay. Motec and top Haltech can do that.

I have some good graphs that explain all this in pictures but my new PC doesn't yet have Excel so I can't open/post them yet.

M.