Best spark plugs for the 575SCi?
08-22-2014, 06:06 AM
#41
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It's safe to say that? Says who? A hot plug is also a great way to burn a hole in the top of a piston of a supercharged engine that already makes higher egts than n/a. Maybe you should stick to sanding bottoms, rather than telling people that a plug 4 heat ranges hotter is safer. Unburied fuel should be handled with proper fuel air management, not with a plug hotter than then surface of the sun.
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08-22-2014, 09:01 AM
#43
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I been running NGK 5673-8 in my engines for years. Mine are supercharged, and carbureted. I do not have plug fouling issues, but, I do have Crane CD ignition boxes, good plug wires, and coil. So that may help.
As far as "heat" generated by blowers, yes, it is true the harder you spin them, the more heat they make. However, if you take a 8-71 and turn it say 1:1, then change pulleys and go 6% over, you wont likely see a huge change in manifold temps.
Icdedppl installed air intake temp gauges under his non intercooled 10-71's, spinning at 3% underdriven. While watching his air temp gauge at 5000+RPM, never saw it go higher than 130*. I'd say on that particular run, we were about 5000RPM for 30 seconds or so doing some carb tuning on the river. Actually the manifold temps were hotter at idle and slow speed, around 140ish. I am not sure how much an intercooler would help on his setup that day. Water temp in the river was probably around 80* and outside air temp was around 83*. It be great if the intercooler could get the intake temp down to ambient, or whatever the lake temp is, but i dont believe the typical superchiller style core is that efficient. or is it?
I personally would love to see some data on manifolds temperatures, on these style blowers, with intercoolers. You would think with Teague, Blower shop, the old LEE intercoolers, someone would have been able to provide some data on temperature change before and after the installation of their product. And not just talking about a quick pull on the dyno. I'd like to see the temps after a long hard run when the outside of the core gets some heat put to it.
As far as "heat" generated by blowers, yes, it is true the harder you spin them, the more heat they make. However, if you take a 8-71 and turn it say 1:1, then change pulleys and go 6% over, you wont likely see a huge change in manifold temps.
Icdedppl installed air intake temp gauges under his non intercooled 10-71's, spinning at 3% underdriven. While watching his air temp gauge at 5000+RPM, never saw it go higher than 130*. I'd say on that particular run, we were about 5000RPM for 30 seconds or so doing some carb tuning on the river. Actually the manifold temps were hotter at idle and slow speed, around 140ish. I am not sure how much an intercooler would help on his setup that day. Water temp in the river was probably around 80* and outside air temp was around 83*. It be great if the intercooler could get the intake temp down to ambient, or whatever the lake temp is, but i dont believe the typical superchiller style core is that efficient. or is it?
I personally would love to see some data on manifolds temperatures, on these style blowers, with intercoolers. You would think with Teague, Blower shop, the old LEE intercoolers, someone would have been able to provide some data on temperature change before and after the installation of their product. And not just talking about a quick pull on the dyno. I'd like to see the temps after a long hard run when the outside of the core gets some heat put to it.
08-22-2014, 09:15 AM
#44
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ok i agree. Not all applications are the same. But we tried it in a few cars that burned oil and it helped.
But back to this discusion. Merc 575s sci's will live for years with Hotter plugs. Is a 250 blower really that much more than a na motor. Only the heat when you crank them up. A 250 is a supercharger but a pretty weak one. Now if i put a 671 on it. That would be serious blower. But i heard they dont make as much heat.
But back to this discusion. Merc 575s sci's will live for years with Hotter plugs. Is a 250 blower really that much more than a na motor. Only the heat when you crank them up. A 250 is a supercharger but a pretty weak one. Now if i put a 671 on it. That would be serious blower. But i heard they dont make as much heat.
So the 256 not much more than an N/A motor huh, you claim you are making 700 HP (you're not BTW), andyou think that power is coming from your 7:5-1 502 iron head engine with a flat tappet cam that is slightly more aggressive than a lawnmower? Take the supercharger off a stock 575sci and you will make about 400 hp, if that.
A larger blower brings in more CFM, therefore you can run lower boost with a larger blower to make the same power as a smaller blower with more boost. Boost is compressed air, more air. Compressing air causes heat, the more it is compressed the hotter it will get. So yes a 8/71 blower will make more power at 3 psi than a 256 at 5 psi, plus the charge will be cooler because the 871 is feeding more CFM. A 256 blower makes 256 cfm per rev, a 6/71 is about 400, and an 8/71 is about 445. if you spin a 256 at twice the rpm of the 8/71 it will make the same or close to the same power. The charge on the 8/71 will however remain cooler, which is worth a few ponies
The 8/71 conversion from dyer is a great set up for a 575sci. I can see that set up making 800 hp with a cam and a little more boost. However, how much can the lower end and a bravo drive handle?
You seem to be butt hurt about something, and I am not sure what it is. Kinda fun to watch.
Any more bad advice you want to throw out there?
Last edited by 4bus; 08-22-2014 at 09:22 AM.
08-22-2014, 09:20 AM
#45
Registered
iTrader: (4)
I been running NGK 5673-8 in my engines for years. Mine are supercharged, and carbureted. I do not have plug fouling issues, but, I do have Crane CD ignition boxes, good plug wires, and coil. So that may help.
As far as "heat" generated by blowers, yes, it is true the harder you spin them, the more heat they make. However, if you take a 8-71 and turn it say 1:1, then change pulleys and go 6% over, you wont likely see a huge change in manifold temps.
Icdedppl installed air intake temp gauges under his non intercooled 10-71's, spinning at 3% underdriven. While watching his air temp gauge at 5000+RPM, never saw it go higher than 130*. I'd say on that particular run, we were about 5000RPM for 30 seconds or so doing some carb tuning on the river. Actually the manifold temps were hotter at idle and slow speed, around 140ish. I am not sure how much an intercooler would help on his setup that day. Water temp in the river was probably around 80* and outside air temp was around 83*. It be great if the intercooler could get the intake temp down to ambient, or whatever the lake temp is, but i dont believe the typical superchiller style core is that efficient. or is it?
I personally would love to see some data on manifolds temperatures, on these style blowers, with intercoolers. You would think with Teague, Blower shop, the old LEE intercoolers, someone would have been able to provide some data on temperature change before and after the installation of their product. And not just talking about a quick pull on the dyno. I'd like to see the temps after a long hard run when the outside of the core gets some heat put to it.
As far as "heat" generated by blowers, yes, it is true the harder you spin them, the more heat they make. However, if you take a 8-71 and turn it say 1:1, then change pulleys and go 6% over, you wont likely see a huge change in manifold temps.
Icdedppl installed air intake temp gauges under his non intercooled 10-71's, spinning at 3% underdriven. While watching his air temp gauge at 5000+RPM, never saw it go higher than 130*. I'd say on that particular run, we were about 5000RPM for 30 seconds or so doing some carb tuning on the river. Actually the manifold temps were hotter at idle and slow speed, around 140ish. I am not sure how much an intercooler would help on his setup that day. Water temp in the river was probably around 80* and outside air temp was around 83*. It be great if the intercooler could get the intake temp down to ambient, or whatever the lake temp is, but i dont believe the typical superchiller style core is that efficient. or is it?
I personally would love to see some data on manifolds temperatures, on these style blowers, with intercoolers. You would think with Teague, Blower shop, the old LEE intercoolers, someone would have been able to provide some data on temperature change before and after the installation of their product. And not just talking about a quick pull on the dyno. I'd like to see the temps after a long hard run when the outside of the core gets some heat put to it.
I know chillers work at idle! My old boat with a sea pump chiller set up used to get so cold in the spring and fall idiling it would pool the fuel and kill my engines, I used to bypass them in all but the hot summer months
Last edited by 4bus; 08-22-2014 at 09:23 AM.
08-22-2014, 09:26 AM
#46
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iTrader: (1)
Okay, Spark Plug 'heat' range is all about transfering heat to the cylinder head.
It's very simple: A hotter plug retains more heat and a cooler plug transfers heat faster to the head.
Combustion chamber heat is what the spark plug sees.
Air temp somewhat contributes to it, but not a bunch unless it gets high enough it causes detonation and such.
More air and more fuel per event causes more BTU's. So, this is a huge factor to spark plug heat range chosen.
RPM is also a factor. More rpm = less time the plug has to transfer it's heat to the cylinder head.
A cylinder head that transfers heat faster to the cooling system will also effect plug heat range> Not a bunch, but some.
All spark plugs must reach a certain actual F* temp or they will foul easily/quickly.
All spark plugs when reaching a certain actual temp will start to turn red hot and thus become an ignition source without spark. That causes pre-ignition and eats motors obviously.
So.....how do we get a plug that runs near hot enough at idle (low rpm/not much BTU's/lot's of time between combustion event to cool off, etc,etc) but doesn't glow hot at high rpms and load ?
Tough.
But, if you have to chose one issue, you choose the colder plug that may foul.
And if you do have to chose this way, meaning foul more often then you want, this is the real reason for big powerful multi strike ignition systems.
Food for thought.
BTW: You can read the ground strap to see if you have the right temp plugs.
Here is one article: http://www.dragstuff.com/techarticle...ead-plugs.html
From NGK: http://www.ngksparkplugs.com/tech_su...k_plugs/p2.asp
It's very simple: A hotter plug retains more heat and a cooler plug transfers heat faster to the head.
Combustion chamber heat is what the spark plug sees.
Air temp somewhat contributes to it, but not a bunch unless it gets high enough it causes detonation and such.
More air and more fuel per event causes more BTU's. So, this is a huge factor to spark plug heat range chosen.
RPM is also a factor. More rpm = less time the plug has to transfer it's heat to the cylinder head.
A cylinder head that transfers heat faster to the cooling system will also effect plug heat range> Not a bunch, but some.
All spark plugs must reach a certain actual F* temp or they will foul easily/quickly.
All spark plugs when reaching a certain actual temp will start to turn red hot and thus become an ignition source without spark. That causes pre-ignition and eats motors obviously.
So.....how do we get a plug that runs near hot enough at idle (low rpm/not much BTU's/lot's of time between combustion event to cool off, etc,etc) but doesn't glow hot at high rpms and load ?
Tough.
But, if you have to chose one issue, you choose the colder plug that may foul.
And if you do have to chose this way, meaning foul more often then you want, this is the real reason for big powerful multi strike ignition systems.
Food for thought.
BTW: You can read the ground strap to see if you have the right temp plugs.
Here is one article: http://www.dragstuff.com/techarticle...ead-plugs.html
From NGK: http://www.ngksparkplugs.com/tech_su...k_plugs/p2.asp
08-22-2014, 10:13 AM
#48
Registered
Check out this
http://teaguecustommarine.com/em0011...-kit-2391.html
08-22-2014, 10:19 AM
#50
Registered
Ugh.......Where do you find your "knowledge" ???
So the 256 not much more than an N/A motor huh, you claim you are making 700 HP (you're not BTW), andyou think that power is coming from your 7:5-1 502 iron head engine with a flat tappet cam that is slightly more aggressive than a lawnmower? Take the supercharger off a stock 575sci and you will make about 400 hp, if that.
A larger blower brings in more CFM, therefore you can run lower boost with a larger blower to make the same power as a smaller blower with more boost. Boost is compressed air, more air. Compressing air causes heat, the more it is compressed the hotter it will get. So yes a 8/71 blower will make more power at 3 psi than a 256 at 5 psi, plus the charge will be cooler because the 871 is feeding more CFM. A 256 blower makes 256 cfm per rev, a 6/71 is about 400, and an 8/71 is about 445. if you spin a 256 at twice the rpm of the 8/71 it will make the same or close to the same power. The charge on the 8/71 will however remain cooler, which is worth a few ponies
The 8/71 conversion from dyer is a great set up for a 575sci. I can see that set up making 800 hp with a cam and a little more boost. However, how much can the lower end and a bravo drive handle?
You seem to be butt hurt about something, and I am not sure what it is. Kinda fun to watch.
Any more bad advice you want to throw out there?
So the 256 not much more than an N/A motor huh, you claim you are making 700 HP (you're not BTW), andyou think that power is coming from your 7:5-1 502 iron head engine with a flat tappet cam that is slightly more aggressive than a lawnmower? Take the supercharger off a stock 575sci and you will make about 400 hp, if that.
A larger blower brings in more CFM, therefore you can run lower boost with a larger blower to make the same power as a smaller blower with more boost. Boost is compressed air, more air. Compressing air causes heat, the more it is compressed the hotter it will get. So yes a 8/71 blower will make more power at 3 psi than a 256 at 5 psi, plus the charge will be cooler because the 871 is feeding more CFM. A 256 blower makes 256 cfm per rev, a 6/71 is about 400, and an 8/71 is about 445. if you spin a 256 at twice the rpm of the 8/71 it will make the same or close to the same power. The charge on the 8/71 will however remain cooler, which is worth a few ponies
The 8/71 conversion from dyer is a great set up for a 575sci. I can see that set up making 800 hp with a cam and a little more boost. However, how much can the lower end and a bravo drive handle?
You seem to be butt hurt about something, and I am not sure what it is. Kinda fun to watch.
Any more bad advice you want to throw out there?
