m20b32 11.0:1 CR cam selection

[ForcedFirebird]

you send it to somebody who knows what they are doing

Best answer! Don't mess with the ports, we ruined some m20 heads in the name of research, and it's very easy to ruin flow.

Adding larger valves just to "port" them and ruin flow, might as well leave the stock valves in and save the machining cost.

[nando]

you send it to somebody who knows what they are doing

if you are going 86mm then the +1 valves should work fine, but your pistons will need to be made so you don't have clearance issues.

[doktor_b]

so, i'm having trouble posting in e30tech.

i've been reading all the threads about head porting/shaping/flow/etc.
my question is this, how do i get my head properly sorted? i ordered all the components. +1mm valves, VAC springs & retainers, all new seals guides, etc.

but i don't have a flow bench. considering the cam and short block build, just a fresh head will make a boatload of power. but i want to go big while i have the chance. do i just send my head off to someone with all my bits and have the ports refined? or should i just cancel the valves and get a fresh valve job on my stock valves and the 288 and leave the ports alone?

[ForcedFirebird]

off top of my head the injector is what 3 to 4" away from the valve? the port is about D38mm(1.5") in that area 2 x invtan 0.75/4 = 22-28* so anything wider than 22-28 degrees (included angle ) will start to hit the wall. how much is too much? is an injector designed for 4V engine best for the 2V?

mainly what im pointing out is how many M20 guys know what the spray pattern of their injectors is and if it is the best one for the job ? ive not really paid attention to it as long as it flows what you want it must be good right?.....fuel preparation is extremely important.

The pintle caps are almost flush with the manifold when installed. Measuring from the manifold gasket to valve is roughly 2", but yeah, guess the walls may be sprayed slightly. The injectors I used are not a very wide angle, but not the "squirt gun" effect like the ancient m20 injectors.

[doktor_b]

I remember when I thought I had a "racecar"...oh and i thought my car was "Low" get real.

I'm flattered that you started troll account just to be a dick to me.


to everyone else, i went ahead and ordered the 288 so we'll see how it goes.

this injector discussion is a ton of good info, albeit a little off track. thanks for all the input!

[digger]

As close as the injectors are in an m20, doubt the spray would hit the port walls. Be interesting to mock up a real world scenario just to see.

off top of my head the injector is what 3 to 4" away from the valve? the port is about D38mm(1.5") in that area 2 x invtan 0.75/4 = 22-28* so anything wider than 22-28 degrees (included angle ) will start to hit the wall. how much is too much? is an injector designed for 4V engine best for the 2V?

mainly what im pointing out is how many M20 guys know what the spray pattern of their injectors is and if it is the best one for the job ? ive not really paid attention to it as long as it flows what you want it must be good right?.....fuel preparation is extremely important.

[ForcedFirebird]

As close as the injectors are in an m20, doubt the spray would hit the port walls. Be interesting to mock up a real world scenario just to see.

[digger]

Yeah... My bad for derailing this one hahaha OP it seems like the 288* cam is a good choice.



To my understanding the 4 pintle (or more...) injectors create better fuel atomization; gasoline does not burn in it's liquid state as we all should know, so the more of a vapor state that it can be introduced into the combustion chamber the better. Right?

Also, the difference between low and high impedance is beneficial to your tuning capabilities... See the link below; questions 3-7 explain this pretty well.

http://fuelinjectorclinic.com/faqs/#3

atomiziation is one thing but whether you spray a narrower pattern directly on the hotter valve or on the colder port walls is a seperate issue. my research says that you dont want to spray too much onto the port walls as it forms rivers of fuel on the runners that doesnt burn well when it gets into the chamber and it is a safe bet the spary onto the valve. but what is too wide and what is too narrow?

[pantelones]

low impedance no longer have any real advantages. the newest high-z injectors are as fast as the low-z injectors of yesteryear, and they're less complicated to control. actually that link says that exact same thing so I dunno if you're agreeing or not. lol

LOL Yes that's what I am pointing out... Trying to be objective and use the link to explain as we have seen where my subjectivity leads haha

[nando]

low impedance no longer have any real advantages. the newest high-z injectors are as fast as the low-z injectors of yesteryear, and they're less complicated to control. actually that link says that exact same thing so I dunno if you're agreeing or not. lol

[pantelones]

we should start another thread lol

Yeah... My bad for derailing this one hahaha OP it seems like the 288* cam is a good choice.

i also wonder about the "newer" injectors and spray patterns and how these compare to the stock ones and if they are any better....

To my understanding the 4 pintle (or more...) injectors create better fuel atomization; gasoline does not burn in it's liquid state as we all should know, so the more of a vapor state that it can be introduced into the combustion chamber the better. Right?

Also, the difference between low and high impedance is beneficial to your tuning capabilities... See the link below; questions 3-7 explain this pretty well.

http://fuelinjectorclinic.com/faqs/#3

[ForcedFirebird]

The root of a good tuner doesn't change, only the software and hardware does. Understanding engine behavior is a dying art. There was no wide band growing up, no ECU's etc. Best form of mass or long distance communication was tele or letter lol.

[digger]

How ironic. Have an 86 944 turbo in the shop right now using a Wolf v5. No locals could get the car to start, its running now, but he has 2cyl with very low comp, engine needs to come apart after a short lived idle tuning.

i would go autronic if had my time again, more tuners available who know the ins and outs of the system.

[ForcedFirebird]

Specially seeing it's an Aussie built unit and also originally ran on Motronic.

[ForcedFirebird]

How ironic. Have an 86 944 turbo in the shop right now using a Wolf v5. No locals could get the car to start, its running now, but he has 2cyl with very low comp, engine needs to come apart after a short lived idle tuning.