matt_lamb_160

I am happy to stick with the sheep on this one... Low mount a turbo in the engine bay where it belongs and have something that works as it should and with zero related issues.

PRO250s setup:

Google M90 on a XFLOW xfalcon On my supercharged 1FZ-FE the blower is mounted on the exhaust side. Allows you to intercool (if you go EFI) and use the standard inlet manifold. Heaps of pictures on the net of similar setups.

No send it to me and I will take it off of your hands for free... ... Yes I would say they are as good a start as any for hotting up.

According to the thread the picture is from they are 48cc. I would've expected them to be closer to the 42cc of the C2 head too.

Less so than a C2 which goes to a sharp point...

Found it:

There are pictures of the D head around somewhere (maybe 9n the other forum). The D is a slightly modified C2 (although I have never had one).

That's harsh and Vizard leaves a lot un-answered, he also relies on smarter people that came before him and often forgets to acknowledge them. But I also get what you mean with the backyard made up physics, myths and magic men. There are tonnes of very smart, very handy self taught engine builders out there that could have saved a lot of time and money by reading.

So you can tie it to your feet and drown yourself? I hear they make great anchors...

No doubt Mr Morgan knows some stuff, but he needs to work on being less condescending in his writing style ("little known fact..." is still making me giggle). Still some good points came out of it. The reality is that if you want an optimized head, you need an engineer to do it and probably one with a PhD and that is going to cost you big time and nobody is going to do it. That's why its great to see Ando and the like putting in hard work and seeing what works for themselves. If we can see what works and what does not we can all reverse engineer to understand why, just like these "professionals". Keep it up guys, I'm too tight and lazy atm so I will sit back and watch you. Build a variable pressure flow bench Ando.

I never doubted your combustion chamber comments if that is why my name is in brackets? I just like to see what has been done and works. Haha... "little known fact". This guy must have just learnt it. I am sure the guy is very smart, but that is a bit rich. The air doesn't stop at the port so that is obvious. But he is correct about the pressure thing which is why Vizard recommends the variable pressure flow bench. The influence of exhaust to inlet port has been understood for decades, but perhaps not the finer details which like everything fluid dynamics related may never fully be. The so called rules of inlet to exhaust ratio only apply if you are using the maximum valve space allowable and are still based on some very old experiments from Charles Taylor (despite some claiming it as their own). So the post is right there too. Making an exhaust valve smaller (unless there is something horrible wrong) is not going to make you faster and if your exhaust is flowing at least 60% of your inlet your not giving that much up. But, if it is flowing 90% you are not either unless you have hammered the port in the process. I think that influence of exhaust tunning is often overstated and Sly's post also suggests a hint of that. The very last point made in Sly's post is the main point, why do we test at a constant arbitrary pressure drop? Because it's easy and gives us a good starting point to work with. If you were to design a new head using CFD, you wouldn't do it, but at least it gives you some information to work with. It is a good post with some good points, but he is still talking in black art.

Flow seperation is a killer, has the effect of making your ports smaller.

Skip smoothing paste and jump to extrusion honing...

If you can find a worthwhile picture I would like to see it here. If you haven't got one, you haven't got one.

Clearly, I meant pictures indicating the material added and where not to take it away from. Perhaps I should have said "pictures showing...", but you knew what I meant.

Just to clear up what broken wheel has said. If that theory (a big if) he has applied is correct, 2.14 sq inches is a 1.65" (43mm) diameter port not 2". Sly, do you have pictures of the material that needs to be built back up opposite the inlet valve that you can add to this thread?

No problem Ando, I understand that this is a competitive world. I was just looking for a way to compare the heads.

Nice one Ando. Can you tell us the maximum port cross-sectional area of each just to give an idea of the differences in the 3 port sizes? I don't think that will give any of your secrets away?

Yeah they are odd.

I would say so yes. Some 5-8cc pistons would be nice with everything else as is, pity we do not have so many options anymore

I just read through to see what cam you have. A 600 vs a 650 is not your big issue (it will work with either), your compression is. You need more (10.5-11:1). If you do not plan on changing this carb to the smaller side and avoid a d/p.

A 600 will "spin" to over 7,000, but it will be a restriction assuming something else isn't limiting it first or to a greater extent. If I was building a 7,000rpm crossflow for the purposes of drag racing, a 650 would be minimum. For a street car which occasionally sees 7k just for fun a 600 is enough. But if it is just a street car put a 450 on it and a 5,500 rpm cam and have a nicer car.

Online carby calculators are never right period. They do not take into account pressure drop across the carb. What revs will you be doing? For most people a 600 is still very big. A 450 4brl will create basically zero restriction upto 5,000rpm, on a street car a 600 will handle just over 6,500. In full drag trim a 650 is good to over 6,500 (not enough for sly at 7,000).

Did you end up pulling the engine down?