combustion chambers
Thread Starter
Pro
Joined: Jan 2009
Posts: 686
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From: Austin Texas
My guess is that you're just pissed since you overlooked those sharp threads in your combustion chambers, and your car gets knock retard way more than it should. LOLLLLLL !!!!!!
Melting Slicks
Joined: Oct 2004
Posts: 2,510
Likes: 4
From: Austin Texas
Exposed threads are proven to rob power, Mike C4. Any hot spots in the chamber which can result in pre-ignition, on knock-retard system equipped vehicles, a single knock in a single cylinder causes timing retard to all cylinders, robbing power. One find many articles written on this, some over 50 years old.
Answer: Cost vs. benefit
(because every head design out there would require a unique plug "grind" , and this would be cost prohibitive.)
Did you know that $40MM = $ 160x10^12 !!!! That's a lot of money !!
Safety Car
Joined: Jan 2008
Posts: 3,939
Likes: 1
From: Vero Beach Florida
Not in a million years would I ever share the fruits of my labors with you, who un-necessarily challenged a simple posting.
My guess is that you're just pissed since you overlooked those sharp threads in your combustion chambers, and your car gets knock retard way more than it should. LOLLLLLL !!!!!!
My guess is that you're just pissed since you overlooked those sharp threads in your combustion chambers, and your car gets knock retard way more than it should. LOLLLLLL !!!!!!
Run me a knock count scan before and after
And you have no idea of what my knowledge is or isn't
So once again you have posted something that you can not prove
I already stated I get no spark knock, but far be it from me to argue with a guy that believes the engineers at GM designed a motor to achieve spark knock because threads were present in the combustion chamber
FAIL
Thread Starter
Pro
Joined: Jan 2009
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From: Austin Texas
Well this certainly begs the question: Why we are sitting here 50 years later without a solution ?
Answer: Cost vs. benefit
(because every head design out there would require a unique plug "grind" , and this would be cost prohibitive.)
Did you know that $40MM = $ 160x10^12 !!!! That's a lot of money !!
Answer: Cost vs. benefit
(because every head design out there would require a unique plug "grind" , and this would be cost prohibitive.)
Did you know that $40MM = $ 160x10^12 !!!! That's a lot of money !!
My guess is that nascar-prepp'd heads don't have any sharp edges in the chambers - including the plug threads. But it wouldn't surprise me if some over look that. If you have eight cyls with exposed sharp edges on the plug bores interior the chamber, I would never bet against at least one of those will be a source of a knock-retard, reducing total engine output. Makes alot of those other expensive details useless if you lose 2 degrees over a friggin spark plug thread !!
Yet I see this on some of the most expensive heads out there. Some may interpret this to mean that "its not a problem", and ask for double-blind studies proving it one way or another.
I don't have the desire to prove anything, only that it is well known in the art that sharp edges are detrimental, and removing them, when the heads are off, only takes 15 minutes at most. Every Man has to make his own decision as to whether its a worthy investment of his time. In my case, I deemed it worthy, and shared, because, as they say "sharing is caring". !!!!
Hey man, have a great day.
Thread Starter
Pro
Joined: Jan 2009
Posts: 686
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From: Austin Texas
Right
Run me a knock count scan before and after
And you have no idea of what my knowledge is or isn't
So once again you have posted something that you can not prove
I already stated I get no spark knock, but far be it from me to argue with a guy that believes the engineers at GM designed a motor to achieve spark knock because threads were present in the combustion chamber
FAIL
Run me a knock count scan before and after
And you have no idea of what my knowledge is or isn't
So once again you have posted something that you can not prove
I already stated I get no spark knock, but far be it from me to argue with a guy that believes the engineers at GM designed a motor to achieve spark knock because threads were present in the combustion chamber
FAIL
I ain't going to twist your arm. I've worked with over 40 engineers, probably over 50, on various projects at a company that is now bankrupt. How many have you worked with ? Most realize that the product that is sold is not exactly what engineers had designed, in many fields due to manufacturing variance.
Thread Starter
Pro
Joined: Jan 2009
Posts: 686
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From: Austin Texas
I never said, as you wrongfully assert, that I believe the engineers at GM designed a motor to achieve spark knock for any reason.
What is it that leads you to conclude that I wrote things that I never did ? I'm not upset at all, just trying to help.
Safety Car
Joined: Jan 2008
Posts: 3,939
Likes: 1
From: Vero Beach Florida
Your statement of working for a company that is now bankrupt is not a convincing qualification of your abilities
I have no knock because I don’t show a code for it, my timing is set correctly, and I have run scans
Once again prove your statement as to overall performance gain or it’s all
I have no knock because I don’t show a code for it, my timing is set correctly, and I have run scans
Once again prove your statement as to overall performance gain or it’s all
Thread Starter
Pro
Joined: Jan 2009
Posts: 686
Likes: 4
From: Austin Texas
Your statement of working for a company that is now bankrupt is not a convincing qualification of your abilities
I have no knock because I don’t show a code for it, my timing is set correctly, and I have run scans
Once again prove your statement as to overall performance gain or it’s all
I have no knock because I don’t show a code for it, my timing is set correctly, and I have run scans
Once again prove your statement as to overall performance gain or it’s all
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Safety Car
Joined: Jan 2008
Posts: 3,939
Likes: 1
From: Vero Beach Florida
I am done with this I'll use exactly what you said before I go "I don't need to provide you with anything !!"
You were the one to make a statement you should back up your words to prove that
You were the one to make a statement you should back up your words to prove that
Thread Starter
Pro
Joined: Jan 2009
Posts: 686
Likes: 4
From: Austin Texas
It could also be that your induction system is such a piece of crap that your volumetric efficiency is so poor that you couldn't gat that crate to knock even running neat n-heptane.
You asked me to disprove a negative, which is impossible, as asking you to disprove the existence of purple eyed 12 legged sheep walking around on the depths of the ocean floor.
I began this thread with a simple helpful hint. You ended it with argument. All you had to initially write was nothing, as most others did, or else "thanks, I'll consider it", instead of proposing that I disprove a negative.
Knock doesn't normally set codes, the engine compensates without setting a code. Chances are that your engine, like most , is not running at its maximal timing advance. If you're happy with it, who am I to argue ? Byb bye.
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
THink Chris is trying to think outside the box and throw it out there for what is worth..Id be interested to see a bone stock L98 which are known for pinging with a stock tune and a scan before and after just for kicks, maybe theres a little something to it. I could see how they could possibly become glow plugs. Or not....ya never know...
He is right about sharp edges in the CC becoming extremely hot though.
My credentials...I went broke all by my little self.
He is right about sharp edges in the CC becoming extremely hot though.
My credentials...I went broke all by my little self.
Le Mans Master
Joined: Jul 1999
Posts: 8,683
Likes: 6
From: Phoenix AZ
Here's a comparison of stock LT4 chambers and modified LT4 chambers;
Stock;
Modified;
There are lots of little tricks that can be used to free up a few extra HP here and there...when a lot of little tricks are used you can see a decent increase. These heads were done by someone that works with GM Racing, and has the largest engine dyno facility in the country (at the time, might not anymore). Plain and simple he knows what works and what doesn't.
This car now runs 11.5:1 compression on 91 octane gas (best I can get in AZ) and puts down 466RWHP.
Stock;
Modified;
There are lots of little tricks that can be used to free up a few extra HP here and there...when a lot of little tricks are used you can see a decent increase. These heads were done by someone that works with GM Racing, and has the largest engine dyno facility in the country (at the time, might not anymore). Plain and simple he knows what works and what doesn't.
This car now runs 11.5:1 compression on 91 octane gas (best I can get in AZ) and puts down 466RWHP.
Le Mans Master
Joined: Jul 1999
Posts: 8,683
Likes: 6
From: Phoenix AZ
The chambers went from about 57cc to 70cc. We were changing the whole engine at the time so we went with flat-top pistons to get the compression back up.
Thread Starter
Pro
Joined: Jan 2009
Posts: 686
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From: Austin Texas
Plus they removed the ridges around the seats. That takes a lot of work since when cutting the seats if your tool is the least bit larger than the seat diameter, it eats into the wall and you have to go back and clean it up later, or if your tool isn't the full diameter you create another ridge - either way work is required. I used a jeweler's eyepiece and more hours than I'll ever admit to when working mine up. Combined with correct backcuts on the valves and optionally radiusing the exhausts, that makes for the ultimate in flow at all lifts. I went a step further and narrowed the seat face on my intake valves so its only about 0.020" wider than the seat. In any event you definitely got your money's worth on those. Thanks for sharing.
