carb or injection?
Turbo Mini Forums

I totally agree Jean, part of my power is from more equal AFRs, absolutly no doubt.

And I too agree that this equates to the fact that the siamese injection WILL make more power than a carb and IS the best injection solution for a 5-port.

But it only makes sens to me if you are after the ultimate 5-port. I am not restricetd to a 5-port head for my hillclimber and for lots of factors chose the 7-port.

But my wet monifold injected 5-port sprint is just a muel and is not about the ultimate anything, I was just after a more controlable carb, so I couldn't justify a long build. It works, it's not perfect, but equally it hasn't yet melted.

Just to be clear, I know the siamese injection is a superior system, but to me, for my cars, it is not the right answer. If I was building a 998 turbo to compete as a road car in hillclimbing where the head has to remain the same, it would be my first choice.

P.S. I don't think I have ever put anyone down for chosing siamese injection.

Edited by wil_h on 23rd Sep, 2011.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

As above.

I'm very interested in proper 5 port injection and your interest post in the for sale section a while ago for a complete siamese kit piqued my interest.

If something is worth doing, it's worth doing half of.

Wil,

I don't think this was addressed at you.

One more thing to consider is that a 5-port injected setup might be easier to package than a 7-port if you start playing with induction size and geometry. That's when it may make more sense even if you're not going for the ultimate setup.

And it should make for a better daily driver than a carb setup too.

Jean

http://www.jbperf.com/

expand on that please Paul.

Edited by apbellamy on 23rd Sep, 2011.

I really hope mine doesn't explode on the dyno after all this! You'll find out soon.

I would also like to say I have no problem with anyone doing siamese injection. As you will hopefully already know from my earlier post. Hats off to you all and I read with interest each update.

I think the thing that is being missed in trying to do any sort of "comparison" is not only that there aren't enough siamese port injection, or even wet manifold injection setups on the road to do meaningfull comparisons (and the few that are, aren't high power monsters... yet) - but the fact that the majority who run the SU don't actually know what is happening.

So far as I know - anyone please correct me if I'm wrong - it's only the few of us trying siamese port injection who actually have widebands on both the inner and outer cylinders so can actually see the AFR differences.

A single wideband just tells you that you can get the average right.

What would be really interesting is if one of the high powered 5 port turbo motors (with an SU) had twin widebands installed - not an easy task with a turbo as they have to go into a sampling tube arrangement to protect them from the pre-turbo temperatures and pressure (both of which skew results) - but anyone going to try it ???

Schrödinger's cat - so which one am I ???

i was thinking about this the other day , i wondered if it would work to drill the manifold and tap it without removing it ,then screw in the fittings ,wack pipes on them both ,take it to a couple of sensor bung cells ,then run it out the side of the engine bay to atmos for a test ....would it back flow enough to distort results ,and would it lose enough boost to mess up the test ?
this would mean one could use just one sensor too.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

It would be interesting to see because that should be the best case scenario in terms of wet manifold setup since the intake charge should have been well mixed up by the supercharger. At least that's how I see it.

Jean

http://www.jbperf.com/

I'll put an extra lambda bung on my to do list then.