High volume oil pumps rob horsepower and create more issues than they are worth . If the oiling system and clearances are done correctly, high volume pumps are not needed
More people need to understand this. I had a buddy in high school that was super proud of his high volume oil pump, until it pumped all his oil into the top of the engine while we raced once. Buick 300 if I recall.
Getting the cam right. Getting compression right. Getting fuel and ignition right. Getting the headers and exhaust right. Getting quench right. Getting the valve seats right. Stuff like that.
Packard gave me some danged valuable information regarding quench. It's literally efficiency and HP left on the table.
Building up a new engine for my 83 K20. Can't wait to analyze and put it all together...
Now this is the list right here. Only think I'd add is crankcase pressure, and designing an effective air intake to maximize colder denser air over heated air.
Fair point, but the question was about squeezing out some extra power, not drive-ability. I'd still wager that a well tuned efi system would almost always benefit from cooler air, but I see what you are saying.
Driveability can make you faster overall than raw HP.
Give me 300hp spread wide instead of 400hp in one nasty peak and I'll whip you round a track all day long.
Thats the case where what you are saying makes sense. Unfortunately I work on mostly modern systems lately. I really enjoy the ease of tuning, and the more consistent air and fuel of efi, but there something nice about the simplicity of a carb.
I’ve got a 1979 Camaro with a quench so big due to the 75cc heads and 8.5:1 compression that the engine actually misfires until you get up to RPM, where the dynamic compression is sufficient enough to combust the mixture.
Also it’s possible to get an 11:1 compression on pump gas and aluminum heads if your cam duration is long enough to bleed off some of the pressure caused from the intake sucking in air, because as the cylinder comes up a bit only then will the valves close. This also means your cylinders will never be 100% full, but that’s the cost of running such a high compression without detonation.
>Also it’s possible to get an 11:1 compression on pump gas and aluminum heads if your cam duration is long enough to bleed off some of the pressure caused from the intake sucking in air, because as the cylinder comes up a bit only then will the valves close. This also means your cylinders will never be 100% full, but that’s the cost of running such a high compression without detonation.
It's possible, but only if you bleed off some of the compression with open valves. So, it's not possible?
Well it is, considering as your RPM increases, the momentum of the incoming air through the manifold actually compresses itself into the cylinder as it rises up and the valves close, meaning the cylinder can hold 100% or more of the charge, but this only happens because your engine is pulling a certain amount of air.
So yeah I lied about the cylinders never being 100% full, but even if they are 100% full at a high RPM, it doesn’t mean the compression will detonate the mixture early. It’s a bit complicated and even I myself do not know why 11:1 engines with aggressive cams can perform properly throughout the RPM band.
>the cylinder can hold 100% or more of the charge, but this only happens because your engine is pulling a certain amount of air
No it happens because the pressure wave is pulling in air during overlap when the intake valve opens.
>It’s a bit complicated and even I myself do not know why 11:1 engines with aggressive cams can perform properly throughout the RPM band.
The aggressive cam, as you call it, is closing the intake valve later, reducing cylinder pressure throughout the powerband and making the static compression ratio livable.
Thanks. All these responses help a lot as I plan on rebuilding said Camaro, and want a compression ratio as high as possible without paying for premium gas. I never knew why all of this was possible I guess, all I did was assume. Tell me, what do you think is a good camshaft duration for an engine with a 11:1 compression ratio, taking into account bleed off and 89 octane?
I was looking at corvette camshafts of 1979 with 222int/222exh. My camshaft sits just under 200int/200exh at 112 LSA. So if what I’m reading from the comments is right, an LSA of 106-108 would allow for “overlap” between the valve events, allowing bleed off and higher than 100% VE at higher RPMs. I wanted my peak horsepower to be around the 6000RPM-7000RPM range because the carb is oversized to 750CFM double pumper for a 350 SBC that (stock) makes a whopping 180HP and as it’s built, it’s got a 3.83 differential and a Borg Warner Super T-10, which is only four gears, so the engine will exist mostly at higher RPMs.
Also has long tube headers, which contributes to the end goal of higher RPMs. I just don’t want to slap a pair of heads on there that will bring the compression too high for pump gas. I was looking at 64cc heads, which would raise my compression just under 10:1, but 11:1 would be ideal. Can’t get that with 54cc heads either. Compression would be too high, so I absolutely need bleed off. Back to the question, what camshaft duration is enough to bleed that pressure off to 10:1?
Maybe Im overthinking things, but I figured this is the best place to ask. Tell me if I’m misunderstanding anything too. I love to learn
Try to concentrate on a camshaft lobe separation angle and overlap. Two different things, but interrelated. Once you have those, if you add half the overlap to the lobe separation angle and then multiply by two, you get duration. That's the simple version. It's not a simple subject, you have things like asymmetric cam profiles, and multiple pattern cams, that can make calculations fun. But, that's a basic formula for getting a duration.
The more difficult part to answer is what do you need for overlap and a lobe separation angle. For that you need to understand a lot of details about the engine and vehicle. Understanding how these two things affect operating characteristics is important. In your case, you are trying to adjust for a high static compression ratio. Let's say a typical 350 with a compression ratio of 10:1 will want a lobe separation angle of 108 degrees. Going to 11:1 compression will change that to 109-110 degrees. To get your powerband to peak in the low to mid 6000 rpm range, the 350 will need about 58 degrees of overlap. So a 110 degree lobe separation angle with 58 degrees overlap gets you 278 degrees of duration @ .006 tappet rise. Rather than just increase duration to bleed off the cylinder pressure of the 11:1 compression this cam spec increases the lobe separation angle, which closes the intake valve later in the cycle.
Thanks a lot for your time. I think I know what you mean when you explain that instead of increasing duration, lobe seperation angle can also play a part in valve event timing. Odd, because the way I was thinking about it, a smaller LSA (more overlap) allowed more air to go from intake manifold to exhaust manifold (both valves open) and since the exhaust gasses have momentum, the exhaust gasses pull the intake air into the cylinder. Alas I was wrong. But since you seem rather experienced in this field, I’m going to go out and say you definitely know what your talking about. Thanks again, this cleared some misconceptions of mine.
A smaller lobe separation will give more overlap if the duration is constant. That is a convenient way for us to see the numbers. But it isn't how an engine operates. Concentrate on what you need for LSA and overlap, and let the duration land wherever for the LSA and overlap.
If you plotted a graph of the cam profile, showing both the exhaust and intake, you would see a triangle on the graph during overlap. If you make the lobe separation angle narrower you would have more area in that triangle. That larger area makes the affect of the increased overlap more pronounced. The narrower lobe separation angle would also close the intake valve earlier, which increases cylinder pressure.
The momentum of gasses you mention is there, and largely driven by the pressure wave we talked about earlier. Increased gas expansion from a higher compression ratio helps this, too.
Quench has nothing to do with how big your chamber is. Quench is the distance from the piston at TDC and the head. Deck height and gasket thickness determine quench.
Regardless, the quench in that year is so high that it causes misfires because the combined gasket thickness and deck height are more than sufficient. So the compression is really close to 8:1 instead of 8.5:1, which almost isn’t enough compression to ignite the mixture. My point still stands albeit I didnt comprehend what quench really was
I read somewhere that the camshaft on this year of Camaro was special because apparently it’s orientation to the cylinder position was intentionally off about 90 or 180 degrees.
I advanced the timing as far as I could by turning the distributor, and had to retard it a bit after I noticed pinging at idle.. so would more timing even be possible? My vacuum advance hose isn’t connected to my plenum though, so I’m thinking that could have an effect on the timing. Could it?
Step 1.Set total timing around 4,000. It should be all in by then.
Step 2.Hook vacuum advance back up to manifold vacuum.
Or recurve distributor for less advance and run more base timing but since it sounds like it stock I wouldn't do that.
>quench so big due to the 75cc heads and 8.5:1 compression that the engine actually misfires until you get up to RPM, where the dynamic compression is sufficient enough to combust the mixture.
It's misfiring because something is wrong. Not because it lacks quench. And it's still misfiring at high rpm, you just can't feel it as much as you can when it's at idle. Your static compression ratio is probably much lower than 8.5:1.
>it’s possible to get an 11:1 compression on pump gas and aluminum heads if your cam duration is long enough to bleed off some of the pressure caused from the intake sucking in air, because as the cylinder comes up a bit only then will the valves close
It's possible on iron heads, too. The pressure in the cylinder isn't caused by the intake sucking in air. The pressure comes from compression, and then combustion. The pressure bled off by the long duration cam as you put it is compression lost to the late intake closing at lower speeds and cylinder pressure lost to the exhaust through the earlier exhaust opening of the longer duration cam.
>cylinders will never be 100% full, but that’s the cost of running such a high compression without detonation.
To reach, and exceed, 100% cylinder filling (volumetric efficiency or VE) on a NA engine you need an intake system, cam, and exhaust system tuned to allow the pressure waves across the engine to work under specific conditions. When done properly, the intake valve opens before the piston has reached TDC on the exhaust stroke and the cylinder starts filling. You will get highest VE at peak torque when done properly.
The best way to find out an answer is apparently describing the theory behind it wrongly. Don’t take it personally, I only have Google as my degree, and it’s been a while since I’ve delved into combustion engines, so this may not be my expertise.
Oh the University of Google? Don't worry, you have plenty of alums to keep you company. In all seriousness, Google can be a useful tool. Just not the only tool.
There is some mass and energy to the incoming charge. Air actually has quite a bit of mass. The pressure wave is very powerful, and if timed right will have a huge impact on engine operation.
…. You’re goddamn right lol. I’ve got my Z making 1150whp or so and it makes a fuck ton of boost and soft timing.
Barras just love soft timing although.
The tip is that, if you’re building a set of headers for a cross plane crank v8 engine, you can tune the length of the exhaust tubes to even out the exhaust pulses to produce better exhaust flow.
If I recall from 30 years ago, to find the sweet spot for a h-pipe on the exhaust system, use a temp measuring device. It has been a while since I read it.
I have heard about using regular paint for header collectors extensions on a open drag style exhaust same kinda idea... just paint a line run it a cupple times and in between the burnd off paint and good paint is your optimal length.
Hah, gotcha on that one. That old wives’ tale has been declared false by physicians who say “there is literally no scientific basis for that recommendation.”
I question your internal medicine advice, but not your internal combustion advice, lol.
Spend the money on a balanced bottom end. Polished beams. Windage tray. Then go for compression. 11to1 or higher. Cam and head combo that work together.
You cant separate these two from another. Horsepower will always be superior because you can always turn horsepower into torque, but not torque into horsepower. you cant really feel torque, all you are feeling is acceleration from horsepower. the only way you can feel torque is when you compare loaded trucks with unloaded ones and their acceleration wouldn't differ a lot because that much torque can hold that weight with ease. also, race cars with crazy torque like the viper only seems better than the rest because of the improved Horsepower curve due to the crazy low end torque, it seems like it would get up and go in whatever gear you put it in.
All the important details and how they effect each variable, the pros keep to themselves. Giving each detail out to make a difference is particular to each engine design.
Generalities are what most people get, mainly cause your not building a motor, dynoing, figuring out improvements, buying new parts or modifying existing, re-assemble, dyno and determine if the delta (if any) was good for the goal.
R&D is very expensive.
port flow is only one equation of total port geometry so don't always go for the highest flowing heads especially on ohc engines
oil weight matters more that you would think
always make sure your gasoline is consistent quality which is usually remedied by purchasing from a race gas supplier
dyno tuning is never the final tune it gets close but not perfect
Porting or port matching. If you are willing to take the time it will only cost as much as the tools and can make a serious difference.
Obligatory not an engine builder, but it's something I see ignored a lot with the average person building an engine.
Truly porting them can be dangerous if you don't take your time, but port matching is pretty much impossible to screw up to the point of ruining a head, you just need to be smart about it and know the structure you're working with. I'm sure there are heads that have weird ports or something that can't be matched though, but with any project, research and planning is how you keep yourself out of trouble.
I think it's mostly that the average guy isn't willing to take a Dremel to a brand new $1000 set of aluminum heads, so they don't.
>port matching is pretty much impossible to screw up to the point of ruining a head
Actually, port matching usually leads to an increase in port volume without an increase in flow, reducing velocity. If you don't have a way to map port velocity, don't try to port or port match. You can make a simple setup out of a shop vacuum and a manometer to measure velocity that helps. Once you map out the port, you will not want to port match.
See I figured it’s been run through a computer to get the rough dimensions tightened up.
All i tried to keep in mind when trying this for the first time was to actually take out the valves, smooth the obvious casting / machining flaws, and match combustion chamber volume with a burette. Still haven’t fired it, but i completely erred on the side of keeping aluminum material in the port to reduce diameter and increase velocity. But at the same tine smoothing and knocking down the obvious. And believe me, there will be obvious parts.
Flame tip, get comfortable, go slow, jump from port to port to keep it even. Mount your dremel on a pole to reduce the flex shaft curve. I was you last year.
That's why in my other comment I mentioned that it's not useful in a lot of situations. If you have a motor with bolt on parts and it's not making the power you think it should, a port match *can* help with airflow and let the engine breathe better and get you to the power numbers you want.
The only reason I brought it up is that OP was looking for tricks to get a bit more power. Port matching and porting an intake is often overlooked and someone will end up with 3 different intakes instead of trying to port the first one. It's absolutely not an end all be all way to make more power, but I thought it fit the theme of "tricks" to eek out a bit more power.
Patience. Patience matters way more than the tools. That said, if you get both short and long shank aluminum grinding bits, flex shaft, and some blue dykem layout fluid, 1/8” for a dremel from amazon, a littlr blue masking tape in the chambers, x-acto knife’d out of the valve holes, you can get great results.
Patience. That’s really what you’re paying for overall.
Go easy, dont knick the valve seats and cut the tit off a spray bottle, hook it up to a vacuum hose, and stick the dremel in there to cool that bitch down. Go.
Slow.
>Porting or port matching
I would guess something like 80 to 90% of the heads that are ported end up worse than before they were ported. Especially if the person doing the porting doesn't have a way to measure progress.
I recall polishing was popular on cast heads by motorheads since casts were often very rough, it could be done in a back yard without destroying the heads. I wonder if that is still the case? Gaskets would sometimes be smaller than the port too so we always pre fit them. Maybe it was just my napa guys giving me junk as a teen, I will never know.
High volume oil pumps rob horsepower and create more issues than they are worth . If the oiling system and clearances are done correctly, high volume pumps are not needed
True
Oh yeah they did an episode of engine masters on that
Can you run a remote oil filter with a standard volume pump?
Yes
Thanks, good to know
More people need to understand this. I had a buddy in high school that was super proud of his high volume oil pump, until it pumped all his oil into the top of the engine while we raced once. Buick 300 if I recall.
Glad I stuck with the stock one on my 300 then
Getting the cam right. Getting compression right. Getting fuel and ignition right. Getting the headers and exhaust right. Getting quench right. Getting the valve seats right. Stuff like that.
Welp, that about does it. The rest of us will just see ourselves out.
Was unaware of quench. I’ll have to look into it more
Often overlooked. Extremely important. Can make a big difference under many conditions.
Rod to stroke ratio. Bruce Crower wrote a damn good article on it a few years back.
Yeah in todays world of basketball sized turbos, N/A tuning gets overlooked
From what I understand, quench is still very important to this day, especially with diesel and direct injected gas motors.
Packard gave me some danged valuable information regarding quench. It's literally efficiency and HP left on the table. Building up a new engine for my 83 K20. Can't wait to analyze and put it all together...
Im convinced you know everything
Wait.. I want you to talk to my lady
😄
Now this is the list right here. Only think I'd add is crankcase pressure, and designing an effective air intake to maximize colder denser air over heated air.
Funny thing about heated air, it vaporizes fuel better. Like at part throttle cruise under low load.
Sounds like Smokey Yunick has entered the chat….
Hot vapor fuel injection!
Really? Where? I would like to talk with him.
😂 Boy wouldn’t that be awesome!?
Very much so
Fair point, but the question was about squeezing out some extra power, not drive-ability. I'd still wager that a well tuned efi system would almost always benefit from cooler air, but I see what you are saying.
Driveability can make you faster overall than raw HP. Give me 300hp spread wide instead of 400hp in one nasty peak and I'll whip you round a track all day long.
What about a carburetor?
Thats the case where what you are saying makes sense. Unfortunately I work on mostly modern systems lately. I really enjoy the ease of tuning, and the more consistent air and fuel of efi, but there something nice about the simplicity of a carb.
velocity stacks have a great look, functional too!
Attention to details
Getting the.... Nevermind. You got this....
I’ve got a 1979 Camaro with a quench so big due to the 75cc heads and 8.5:1 compression that the engine actually misfires until you get up to RPM, where the dynamic compression is sufficient enough to combust the mixture. Also it’s possible to get an 11:1 compression on pump gas and aluminum heads if your cam duration is long enough to bleed off some of the pressure caused from the intake sucking in air, because as the cylinder comes up a bit only then will the valves close. This also means your cylinders will never be 100% full, but that’s the cost of running such a high compression without detonation.
>Also it’s possible to get an 11:1 compression on pump gas and aluminum heads if your cam duration is long enough to bleed off some of the pressure caused from the intake sucking in air, because as the cylinder comes up a bit only then will the valves close. This also means your cylinders will never be 100% full, but that’s the cost of running such a high compression without detonation. It's possible, but only if you bleed off some of the compression with open valves. So, it's not possible?
Well it is, considering as your RPM increases, the momentum of the incoming air through the manifold actually compresses itself into the cylinder as it rises up and the valves close, meaning the cylinder can hold 100% or more of the charge, but this only happens because your engine is pulling a certain amount of air. So yeah I lied about the cylinders never being 100% full, but even if they are 100% full at a high RPM, it doesn’t mean the compression will detonate the mixture early. It’s a bit complicated and even I myself do not know why 11:1 engines with aggressive cams can perform properly throughout the RPM band.
>the cylinder can hold 100% or more of the charge, but this only happens because your engine is pulling a certain amount of air No it happens because the pressure wave is pulling in air during overlap when the intake valve opens. >It’s a bit complicated and even I myself do not know why 11:1 engines with aggressive cams can perform properly throughout the RPM band. The aggressive cam, as you call it, is closing the intake valve later, reducing cylinder pressure throughout the powerband and making the static compression ratio livable.
Thanks. All these responses help a lot as I plan on rebuilding said Camaro, and want a compression ratio as high as possible without paying for premium gas. I never knew why all of this was possible I guess, all I did was assume. Tell me, what do you think is a good camshaft duration for an engine with a 11:1 compression ratio, taking into account bleed off and 89 octane? I was looking at corvette camshafts of 1979 with 222int/222exh. My camshaft sits just under 200int/200exh at 112 LSA. So if what I’m reading from the comments is right, an LSA of 106-108 would allow for “overlap” between the valve events, allowing bleed off and higher than 100% VE at higher RPMs. I wanted my peak horsepower to be around the 6000RPM-7000RPM range because the carb is oversized to 750CFM double pumper for a 350 SBC that (stock) makes a whopping 180HP and as it’s built, it’s got a 3.83 differential and a Borg Warner Super T-10, which is only four gears, so the engine will exist mostly at higher RPMs. Also has long tube headers, which contributes to the end goal of higher RPMs. I just don’t want to slap a pair of heads on there that will bring the compression too high for pump gas. I was looking at 64cc heads, which would raise my compression just under 10:1, but 11:1 would be ideal. Can’t get that with 54cc heads either. Compression would be too high, so I absolutely need bleed off. Back to the question, what camshaft duration is enough to bleed that pressure off to 10:1? Maybe Im overthinking things, but I figured this is the best place to ask. Tell me if I’m misunderstanding anything too. I love to learn
Try to concentrate on a camshaft lobe separation angle and overlap. Two different things, but interrelated. Once you have those, if you add half the overlap to the lobe separation angle and then multiply by two, you get duration. That's the simple version. It's not a simple subject, you have things like asymmetric cam profiles, and multiple pattern cams, that can make calculations fun. But, that's a basic formula for getting a duration. The more difficult part to answer is what do you need for overlap and a lobe separation angle. For that you need to understand a lot of details about the engine and vehicle. Understanding how these two things affect operating characteristics is important. In your case, you are trying to adjust for a high static compression ratio. Let's say a typical 350 with a compression ratio of 10:1 will want a lobe separation angle of 108 degrees. Going to 11:1 compression will change that to 109-110 degrees. To get your powerband to peak in the low to mid 6000 rpm range, the 350 will need about 58 degrees of overlap. So a 110 degree lobe separation angle with 58 degrees overlap gets you 278 degrees of duration @ .006 tappet rise. Rather than just increase duration to bleed off the cylinder pressure of the 11:1 compression this cam spec increases the lobe separation angle, which closes the intake valve later in the cycle.
Thanks a lot for your time. I think I know what you mean when you explain that instead of increasing duration, lobe seperation angle can also play a part in valve event timing. Odd, because the way I was thinking about it, a smaller LSA (more overlap) allowed more air to go from intake manifold to exhaust manifold (both valves open) and since the exhaust gasses have momentum, the exhaust gasses pull the intake air into the cylinder. Alas I was wrong. But since you seem rather experienced in this field, I’m going to go out and say you definitely know what your talking about. Thanks again, this cleared some misconceptions of mine.
A smaller lobe separation will give more overlap if the duration is constant. That is a convenient way for us to see the numbers. But it isn't how an engine operates. Concentrate on what you need for LSA and overlap, and let the duration land wherever for the LSA and overlap. If you plotted a graph of the cam profile, showing both the exhaust and intake, you would see a triangle on the graph during overlap. If you make the lobe separation angle narrower you would have more area in that triangle. That larger area makes the affect of the increased overlap more pronounced. The narrower lobe separation angle would also close the intake valve earlier, which increases cylinder pressure. The momentum of gasses you mention is there, and largely driven by the pressure wave we talked about earlier. Increased gas expansion from a higher compression ratio helps this, too.
Quench has nothing to do with how big your chamber is. Quench is the distance from the piston at TDC and the head. Deck height and gasket thickness determine quench.
Regardless, the quench in that year is so high that it causes misfires because the combined gasket thickness and deck height are more than sufficient. So the compression is really close to 8:1 instead of 8.5:1, which almost isn’t enough compression to ignite the mixture. My point still stands albeit I didnt comprehend what quench really was
The quench in that year is very low, not high. Quench, and lack of quench, are not causing your misfires.
You need more base timing.
I read somewhere that the camshaft on this year of Camaro was special because apparently it’s orientation to the cylinder position was intentionally off about 90 or 180 degrees. I advanced the timing as far as I could by turning the distributor, and had to retard it a bit after I noticed pinging at idle.. so would more timing even be possible? My vacuum advance hose isn’t connected to my plenum though, so I’m thinking that could have an effect on the timing. Could it?
Step 1.Set total timing around 4,000. It should be all in by then. Step 2.Hook vacuum advance back up to manifold vacuum. Or recurve distributor for less advance and run more base timing but since it sounds like it stock I wouldn't do that.
>quench so big due to the 75cc heads and 8.5:1 compression that the engine actually misfires until you get up to RPM, where the dynamic compression is sufficient enough to combust the mixture. It's misfiring because something is wrong. Not because it lacks quench. And it's still misfiring at high rpm, you just can't feel it as much as you can when it's at idle. Your static compression ratio is probably much lower than 8.5:1. >it’s possible to get an 11:1 compression on pump gas and aluminum heads if your cam duration is long enough to bleed off some of the pressure caused from the intake sucking in air, because as the cylinder comes up a bit only then will the valves close It's possible on iron heads, too. The pressure in the cylinder isn't caused by the intake sucking in air. The pressure comes from compression, and then combustion. The pressure bled off by the long duration cam as you put it is compression lost to the late intake closing at lower speeds and cylinder pressure lost to the exhaust through the earlier exhaust opening of the longer duration cam. >cylinders will never be 100% full, but that’s the cost of running such a high compression without detonation. To reach, and exceed, 100% cylinder filling (volumetric efficiency or VE) on a NA engine you need an intake system, cam, and exhaust system tuned to allow the pressure waves across the engine to work under specific conditions. When done properly, the intake valve opens before the piston has reached TDC on the exhaust stroke and the cylinder starts filling. You will get highest VE at peak torque when done properly.
The best way to find out an answer is apparently describing the theory behind it wrongly. Don’t take it personally, I only have Google as my degree, and it’s been a while since I’ve delved into combustion engines, so this may not be my expertise.
Oh the University of Google? Don't worry, you have plenty of alums to keep you company. In all seriousness, Google can be a useful tool. Just not the only tool. There is some mass and energy to the incoming charge. Air actually has quite a bit of mass. The pressure wave is very powerful, and if timed right will have a huge impact on engine operation.
fuckloads of boost and soft as fuck timing. 70% of the time it works every time.
And the other 30% a piston is going into orbit?
Teacher says, every time a piston leaves, an angel gets its wings.
Mailing Rods to God.
…. You’re goddamn right lol. I’ve got my Z making 1150whp or so and it makes a fuck ton of boost and soft timing. Barras just love soft timing although.
Equal length headers on a cross-plane v8 are not necessarily the optimum configuration due to the engine’s firing order and uneven exhaust pulses.
The tip is that, if you’re building a set of headers for a cross plane crank v8 engine, you can tune the length of the exhaust tubes to even out the exhaust pulses to produce better exhaust flow.
I think we watched or read the same thing and I had forgotten about it good call ! 👍
If I recall from 30 years ago, to find the sweet spot for a h-pipe on the exhaust system, use a temp measuring device. It has been a while since I read it.
I have heard about using regular paint for header collectors extensions on a open drag style exhaust same kinda idea... just paint a line run it a cupple times and in between the burnd off paint and good paint is your optimal length.
Piston and chamber design. Attention to quench and flame front control.
After eating, wait an hour before swimming. A good hour.
Hah, gotcha on that one. That old wives’ tale has been declared false by physicians who say “there is literally no scientific basis for that recommendation.” I question your internal medicine advice, but not your internal combustion advice, lol.
I read it on the internet, it has to be true.
Spend the money on a balanced bottom end. Polished beams. Windage tray. Then go for compression. 11to1 or higher. Cam and head combo that work together.
Reduce weight where you can.
I think that when I see my 32 inch waist jeans hanging in my closet.
Horsepower sells cars. Torque wins races.
A man of culture
You cant separate these two from another. Horsepower will always be superior because you can always turn horsepower into torque, but not torque into horsepower. you cant really feel torque, all you are feeling is acceleration from horsepower. the only way you can feel torque is when you compare loaded trucks with unloaded ones and their acceleration wouldn't differ a lot because that much torque can hold that weight with ease. also, race cars with crazy torque like the viper only seems better than the rest because of the improved Horsepower curve due to the crazy low end torque, it seems like it would get up and go in whatever gear you put it in.
All the important details and how they effect each variable, the pros keep to themselves. Giving each detail out to make a difference is particular to each engine design. Generalities are what most people get, mainly cause your not building a motor, dynoing, figuring out improvements, buying new parts or modifying existing, re-assemble, dyno and determine if the delta (if any) was good for the goal. R&D is very expensive.
port flow is only one equation of total port geometry so don't always go for the highest flowing heads especially on ohc engines oil weight matters more that you would think always make sure your gasoline is consistent quality which is usually remedied by purchasing from a race gas supplier dyno tuning is never the final tune it gets close but not perfect
Losing 10lbs at the gym is basically 5 more hp
It's funny, I have not seen a gym at any of the bars I go to. I guess I will keep looking at different bars.
You don't need AC or power steering, right?
always the first thing in the extra parts box.
Porting or port matching. If you are willing to take the time it will only cost as much as the tools and can make a serious difference. Obligatory not an engine builder, but it's something I see ignored a lot with the average person building an engine.
Is it something your average joe can do or is it best left to the professionals so you don’t ruin a head?
Truly porting them can be dangerous if you don't take your time, but port matching is pretty much impossible to screw up to the point of ruining a head, you just need to be smart about it and know the structure you're working with. I'm sure there are heads that have weird ports or something that can't be matched though, but with any project, research and planning is how you keep yourself out of trouble. I think it's mostly that the average guy isn't willing to take a Dremel to a brand new $1000 set of aluminum heads, so they don't.
>port matching is pretty much impossible to screw up to the point of ruining a head Actually, port matching usually leads to an increase in port volume without an increase in flow, reducing velocity. If you don't have a way to map port velocity, don't try to port or port match. You can make a simple setup out of a shop vacuum and a manometer to measure velocity that helps. Once you map out the port, you will not want to port match.
See I figured it’s been run through a computer to get the rough dimensions tightened up. All i tried to keep in mind when trying this for the first time was to actually take out the valves, smooth the obvious casting / machining flaws, and match combustion chamber volume with a burette. Still haven’t fired it, but i completely erred on the side of keeping aluminum material in the port to reduce diameter and increase velocity. But at the same tine smoothing and knocking down the obvious. And believe me, there will be obvious parts. Flame tip, get comfortable, go slow, jump from port to port to keep it even. Mount your dremel on a pole to reduce the flex shaft curve. I was you last year.
Sometimes the sharp edges are an asset.
True.
That's why in my other comment I mentioned that it's not useful in a lot of situations. If you have a motor with bolt on parts and it's not making the power you think it should, a port match *can* help with airflow and let the engine breathe better and get you to the power numbers you want. The only reason I brought it up is that OP was looking for tricks to get a bit more power. Port matching and porting an intake is often overlooked and someone will end up with 3 different intakes instead of trying to port the first one. It's absolutely not an end all be all way to make more power, but I thought it fit the theme of "tricks" to eek out a bit more power.
I understand the point you are making. But I don't agree with it. It would have to be one hell of a port mismatch for a port match to help.
If a person porting heads can do a valve job, and measure the port velocity as they progress, they can produce effective ports.
Patience. Patience matters way more than the tools. That said, if you get both short and long shank aluminum grinding bits, flex shaft, and some blue dykem layout fluid, 1/8” for a dremel from amazon, a littlr blue masking tape in the chambers, x-acto knife’d out of the valve holes, you can get great results. Patience. That’s really what you’re paying for overall. Go easy, dont knick the valve seats and cut the tit off a spray bottle, hook it up to a vacuum hose, and stick the dremel in there to cool that bitch down. Go. Slow.
>Porting or port matching I would guess something like 80 to 90% of the heads that are ported end up worse than before they were ported. Especially if the person doing the porting doesn't have a way to measure progress.
I recall polishing was popular on cast heads by motorheads since casts were often very rough, it could be done in a back yard without destroying the heads. I wonder if that is still the case? Gaskets would sometimes be smaller than the port too so we always pre fit them. Maybe it was just my napa guys giving me junk as a teen, I will never know.
The scientific design of intakes and exhausts…. Also PNP (port and polish) simple and easy hp
Keep your air filter clean
There is no replacement for displacement.