Gra onto ea centre point manifold.

[Ando81 2,949]

So I've been talking to my local ford mechanic and he said he put an impco mixer onto efi crossy using the efi induction pipes. It was used in a 5 tonne truck and he said it pulled quite well with an impco 225 mixer. Can someone remind me the downside of using efi induction pipes again, I remember something bad about uneven flow or something. This would be a simpler fix for better towing performance in my xf ute but is it going to be restricted in some way. Thoughts????

[gerg 10,871]

Flow difference only matters at higher rpm, down low it doesn't make much difference.

 

"pulled quite well" sounds like it did exactly what was asked of it: push a big lump of truck along with minimal effort. Doesn't sound like much of a performance engine to me though.

 

An impco 225 is not a performance unit, from what I've found it apparently flows 329 cfm. Using the EFI runners and plenum will put a limit on how much power you can make regardless of what mixer you use.

 

Another drama is the shitty design fault of having the air box sit over the exhaust manifold. My dad's one always got stupid hot and I always wondered how much difference that'd make to performance.

 

Best gas setup would have large runners and a decent plenum. An Aussiespeed with a 425 would work very well but I know they're expensive and not what you had in mind.

 

Another angle: Try and find an impco 300A and put that on the cfi manifold. They can flow a lot more than a 225, which is a little small for a big 6.

 

I guess you could try and port out the EFI plenum to take off the sharp edges going into the runners, perhaps match-port the bottom of the runners to the injector plate.

 

Just purely guessing, I should think you'd max out at about 100 rwkw with a 225 on the bunch of bananas manifold.

[Ando81 2,949]

Thanks mate, I really appreciate your knowledge on this. I was hoping to eliminate the air box if possible but not sure if I can. I reckon I'll look for a 300a to put on the bunch of bananas and I'll port the manifold to suit. Thanks again for your input.

[gerg 10,871]

Lol... I'm not a gas fitter and dont consider myself an expert, just owned a couple of gas cars and played with them. TF corty 4.1 straight gas with a Nolff's 300 mixer on a 2-barrel redline. Went well but not a revver. Would have benefited with MSD programmable. Then I had an EA S-Pack dual fuel with an impco 225 inline and that went ok, nothing spesh just did the job.

[Ando81 2,949]

Ok thanks, yeah I'm not after something that's gunna rev to 6000rpm, I just want a bit of torque for pulling power. Thanks again for the help.

[PRO250 1,506]

ill sugest a turbo with that LPG  that will pull jesus off the cross

[gerg 10,871]

Sounds like a yummy combination to me

[Ando81 2,949]

Dave......... I'm trying to do a cheap power upgrade. If you keep tempting me like that I will be broke in no time

[matt_lamb_160 252]

A 1&20 300a flows no more than a 225 and will be harder to fit on a banana manifold. If you don't rev over 4k I would use a 225 and a banana manifold. It will go way better than a 4brl manifold and 50&70 300a or 425 below 2,200rpm, but not as good beyond 4k.

 

Don't use an OMVL RE90 unless you want to chew gas and make no power. Impco meter well and are a piece of piss to tune, so I see no point to GRA either, they are unnecessary $$$ in my mind.

[Ando81 2,949]

My omvl re90 is exactly doing that, chewing gas and making no power

[matt_lamb_160 252]

A 1&20 300a on a 2brl manifold is neat and good though, just make sure it is a good spacer under it NOT a carby.

[matt_lamb_160 252]

Yeah the OMVL setups don't work. The converters are good for HP, but mixer rings are not. Even with an air-rod variable mixer you use way more gas to make the same power as an Impco setup and the mixtures will vary way more. My turbo'ed Impco setup uses way less gas than my 180-200HP air-rod powered crossy did

[gerg 10,871]

I didn't like the fine-tune screw on my 225, it made absolutely no difference to performance or economy winding it in or out, you could even remove it altogether!

 

I had more success with my Nolff's NCA300, which had a screw down the middle of the needle. Wasn't sure if it moved the whole needle up or down or just changed the stop position of the diaphragm at idle.

[matt_lamb_160 252]

Middle screw on a 300a is idle only. Squared one on the bit that bolts on is the "power valve"

[gerg 10,871]

Yeah pretty rough adjustment on that hi-speed one... It's basically a tap that restricts max flow. You only have 0-90 deg of adjustment.

[matt_lamb_160 252]

Pretty easy to get pretty good.