How a combustion chamber takes shape at HeadGames
May 5, 2010, 10:02 AM
#65
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you would port them the same...the only combo I have found that reacts different is BIG nitrous shots like BIG exhaust ports. When I say big, 800hp+ in nitrous, the bigger I make the exhaust port the more power it makes. Everything else stays the same. We used to treat the turbo stuff like the nitrous heads..but we started to make them smaller and went smaller on the valves, picked up power and tons of torque. You do see some heads, even on here that make the intake way bigger then it should be, and only think the same logic of bigger port because the turbo supplies the velocity is applied. Air may be blind, but it's not stupid. It likes tight spaces and nice or slight turns..nothing abrupt or spacious
Interesting note about your nitrous heads, the same is true in the Turbo ProMod stuff. Some of those heads have bigger exhaust valves than intake.
May 5, 2010, 11:55 AM
#66
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I sent you an email in reference to this a week or so ago. I dunno if Casey Snyder was your teacher at SAM, but he's still teaching the "make it big" philosophy when it comes to 40+psi heads. He says exactly what you just said is wrong. Are you refering to "low" boost applications? Do you find a difference on the big power stuff?
Interesting note about your nitrous heads, the same is true in the Turbo ProMod stuff. Some of those heads have bigger exhaust valves than intake.
Interesting note about your nitrous heads, the same is true in the Turbo ProMod stuff. Some of those heads have bigger exhaust valves than intake.
Casey and I actually went to school together, I think he graduated around the same time. And he was working for Greg Good. And Greg was the main teacher there. We still keep in contact...
we don't really subscribe to the "make it big" philosophy per say. I mean certainly something running 60-70psi will have a larger port but it won't be gigantic. It won't be as big as we can make it. It won't have the largest valve we can stick in it. You can make around 1000whp on almost every sport compact platform with a stock size valve. Valve material is more of a concern over 40psi then anything. Like Judson would preach(not about cylinder heads, but otherwise) In head porting, if your going to be off, you want to be off small . To small you know it, to big, everyone knows it. As surely it will run like a dog with flees.
Small story...I agree, Casey and Greg are a make it big guys. And when I left the school I started at Pat Musi's and of course alot of ProMod stuff there and they were under the same philosophy. Maybe I was their 6 months or so, and I asked the other head porter their what he wanted me to do with the set of Dart Big Chiefs I was working on. Annoyed by my surely constant questions of what to do, he said "your the head porter, what do you want to do with them"...I make them smaller, made the short turn face the cylinder wall and they put them on the motor. It picked up 70hp on the dyno! I got a raise that day, and realized I am on the right track. Bigger is not better, it just sounds better.
May 5, 2010, 12:43 PM
#67
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The short answer is yes, flame propagation is a consideration..but with there is far less room in most sport compact heads to impact it from a head porting point of view. We can move material around in the chamber, but not that much.
this is what we are talking about on a SR20 head..looking at the back side of the chambers, behind the valves...
unfortunately this is the best I could find of taking the material out, if you look at the last few chambers you can see what we are talking about
Again, not a fan of it..but it's hard to argue with results. The bottom pic, that head went on the fastest 240 in the country, and won a NHRA and NOPI championship.
this is what we are talking about on a SR20 head..looking at the back side of the chambers, behind the valves...
unfortunately this is the best I could find of taking the material out, if you look at the last few chambers you can see what we are talking about
Again, not a fan of it..but it's hard to argue with results. The bottom pic, that head went on the fastest 240 in the country, and won a NHRA and NOPI championship.
any reason why you arent a fan of it? my built head for a different car application (srt4)had the same process done to it.
kind of a stock-ish chamber, just to give an idea. couldn't find a stock CC, but it's kinda close.
and here's my combustion chamber w/ it sphericalized (for lack of better words...lol, not too savvy w/ terminology for this stuff).
is there a pro/con to the bottom provided pic's combustion chamber vs. a rather stock combustion chamber shape design? i assume more volume, and less chance for detonation since any raised/recessed areas are taken down to a uniform level.
Last edited by norcalSRTrida; May 5, 2010 at 12:45 PM.
May 5, 2010, 07:08 PM
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any reason why you arent a fan of it? my built head for a different car application (srt4)had the same process done to it.
is there a pro/con to the bottom provided pic's combustion chamber vs. a rather stock combustion chamber shape design? i assume more volume, and less chance for detonation since any raised/recessed areas are taken down to a uniform level.
is there a pro/con to the bottom provided pic's combustion chamber vs. a rather stock combustion chamber shape design? i assume more volume, and less chance for detonation since any raised/recessed areas are taken down to a uniform level.
as I said...it goes against what I would normally think, but it has worked in so many applications. I actually talked to Brian Tooley today from TFS (cylinder head company) and he was telling me about a customer that they took the quench pads out and went from 187mph to 192mph! It works, I guess I would just save it for a engine making over 1000 and over 40-50 psi for it to be a consideration of going thru the trouble of doing it. And even knowing it works, I still don't like doing it,lol
Jan 13, 2011, 09:39 AM
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This removing the quench pads is a very interesting topic and smashes some of the theories I held dear for a long time .
Basically I though that minimising the end gasses left less charge to potentially detonate but what you're telling me result wise sends that theory packing .
I guess in the end heat and pressure set a detonation threshold at some point and I suppose anything you can do to reduce the temperature gives a bit more margin against auto ignition so to speak .
To head games I need to PM you about some techniques because like the other fella its not economically viable to sent you a casting from the other side of the planet .
Just to round off Mitsubishi would have had their reasons for designing their 63 head the way they did , being production based they would have had to take emissions , and to some degree fuel consumption , into account and of course packaging .
Great info , cheers Adrian .
Basically I though that minimising the end gasses left less charge to potentially detonate but what you're telling me result wise sends that theory packing .
I guess in the end heat and pressure set a detonation threshold at some point and I suppose anything you can do to reduce the temperature gives a bit more margin against auto ignition so to speak .
To head games I need to PM you about some techniques because like the other fella its not economically viable to sent you a casting from the other side of the planet .
Just to round off Mitsubishi would have had their reasons for designing their 63 head the way they did , being production based they would have had to take emissions , and to some degree fuel consumption , into account and of course packaging .
Great info , cheers Adrian .
Jan 13, 2011, 03:00 PM
#72
I've heard of another company doing back to back tests removing the quench pads in the 3S-GTE motor. The car lost HP on a given tune, but the motor was able to tolerate like 4-6 more degrees of ignition advance which in the end made for considerable gains overall.
I think it is one of those things, if you have the turbo maxed and the fuel stability to reach MBT with either setup, keeping the quench pads is likely better. But if you reach the point where you are running into detonation before MBT, ditching the quench pads may give you gains in the end.
I think it is one of those things, if you have the turbo maxed and the fuel stability to reach MBT with either setup, keeping the quench pads is likely better. But if you reach the point where you are running into detonation before MBT, ditching the quench pads may give you gains in the end.
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