Another Ricer gets a 944 series...this time, it's PERSONAL
08-07-2005, 12:42 AM
#122
Campeck:: "k. re-read alittle deeper. are you saying that an engine on NOS will not detonate at all?"
It's a hell of a lot less likely to than a N/A or turbo/supercharged engine for the simple fact that nitrous enters the engine at about -20 degrees farenhiet.
I ask you, what causes detonation? Uncontrolled burning of the fuel air mixture due to spontaneous combustion of the charge before the plug fires is what causes it. What causes that?
Heat in the combustion chamber.
What effect does pumping 20 below zero nitrous have on a hot combustion chamber?
It massively cools it...making it far less prone to detonation.
If the fuel solenoid fails on a 75 shot the AFR immediately spikes to about 17-18:1, and the motor wants to just about stall. According to Mark Kibbort detonation is most prone to occur at Stoichiometric(14.7:1), as that's the AFR that creates the highest cylinder temps(hence it being desirable from an emmissions standpoint). At 17:1+ the motor just wants to cut right out, so detonation never really occurs.
It is for this odd reason that a smaller 50 shot, or even a 'sneaky pete' 25 shot can be potentially more dangerous wrt spiking combustion chamber temps and detonation. If a 250 shot were to suddenly have it's fuel solenoids cut out the engine would just flat stall(you're talking an AFR of about 25-30:1 in such a case).
"your saying that when an engine on NOS fails it's cause of the pressures of the cylinder?"
Yep, and the stresses on the bottom end. There are of course, exceptions.
"if so i find that hard to believe that an engine on nitro won't detonate. fishey?"
"Nitro" is nitromethane. That's what top fuel dragsters run on. We're talking about 'nitrous'.
There's nothing magical about nitrous except for the massive cooling effect of the intake charge. Beyond that, it's doing the exact same thing that bigger heads, bigger cam, or turbo/superchargers do...stuffing more air/fuel into the cylinders.
Nitrous, the other 'boost'.
It's a hell of a lot less likely to than a N/A or turbo/supercharged engine for the simple fact that nitrous enters the engine at about -20 degrees farenhiet.
I ask you, what causes detonation? Uncontrolled burning of the fuel air mixture due to spontaneous combustion of the charge before the plug fires is what causes it. What causes that?
Heat in the combustion chamber.
What effect does pumping 20 below zero nitrous have on a hot combustion chamber?
It massively cools it...making it far less prone to detonation.
If the fuel solenoid fails on a 75 shot the AFR immediately spikes to about 17-18:1, and the motor wants to just about stall. According to Mark Kibbort detonation is most prone to occur at Stoichiometric(14.7:1), as that's the AFR that creates the highest cylinder temps(hence it being desirable from an emmissions standpoint). At 17:1+ the motor just wants to cut right out, so detonation never really occurs.
It is for this odd reason that a smaller 50 shot, or even a 'sneaky pete' 25 shot can be potentially more dangerous wrt spiking combustion chamber temps and detonation. If a 250 shot were to suddenly have it's fuel solenoids cut out the engine would just flat stall(you're talking an AFR of about 25-30:1 in such a case).
"your saying that when an engine on NOS fails it's cause of the pressures of the cylinder?"
Yep, and the stresses on the bottom end. There are of course, exceptions.
"if so i find that hard to believe that an engine on nitro won't detonate. fishey?"
"Nitro" is nitromethane. That's what top fuel dragsters run on. We're talking about 'nitrous'.
There's nothing magical about nitrous except for the massive cooling effect of the intake charge. Beyond that, it's doing the exact same thing that bigger heads, bigger cam, or turbo/superchargers do...stuffing more air/fuel into the cylinders.
Nitrous, the other 'boost'.
Last edited by m21sniper; 08-07-2005 at 02:18 AM.
08-07-2005, 12:46 AM
#123
Campeck: "im about to start reading my LAST book about engines. lol..read to many. and the engine out of the kalahari car will be uber pimped in hp standars. i cant wait!"
Don't stop reading till you've read "Theories of Turbocharging", by Corky Bell.
Not because of what it will teach you about turbo systems(which is quite a lot), but because of the understanding you'll gain of the stresses and dynamics at play in reciprocating engines.
Don't stop reading till you've read "Theories of Turbocharging", by Corky Bell.
Not because of what it will teach you about turbo systems(which is quite a lot), but because of the understanding you'll gain of the stresses and dynamics at play in reciprocating engines.
08-07-2005, 01:27 AM
#124
Campeck Rulez
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Way ahead of you man! That was the first book I picked up! 
OOOOO!!!! I had no idea that nitrous came out that cold! It all makes sense now. see. I though it was at ambient temps inside the bottle. and on release...just...kinda stayed that way. and then the extra power would cause heat = detontation. but dang..if its 20Deg below then yeah. WHat your saying makes sense to me now. thanks. learn something new every day huh?
OOOOO!!!! I had no idea that nitrous came out that cold! It all makes sense now. see. I though it was at ambient temps inside the bottle. and on release...just...kinda stayed that way. and then the extra power would cause heat = detontation. but dang..if its 20Deg below then yeah. WHat your saying makes sense to me now. thanks. learn something new every day huh?
08-07-2005, 01:38 AM
#125
Campeck Rulez
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As the collection stands at the moment.
I got to the project car parts of the ECU tuning book and stopped. I need to pick back up. that book was INVALUABLE!
the other two hardbooks i need to read.
I got to the project car parts of the ECU tuning book and stopped. I need to pick back up. that book was INVALUABLE!
the other two hardbooks i need to read.
08-07-2005, 01:56 AM
#127
Three Wheelin'
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yeah, i love them flairs, thats why i bought one! then again i am just turning around and selling it, but its still awesome to look at in the garage! ::comes back 30 seconds later:: yeah ur right...yummy! but sadly the 924s top speed wise will never be able to surpass the 944 since the trany has lower gear ratios. i love how first can take the 944 all the way up around 40mph!
oh and there was no funny business on the dyno, i just got the sheet and stated what it told me. i guess it could have been faulty, but i doubt a pro car shop would be off so much yanno?
in my 924s, since it is geared lower, it is a lot easier to get to the higher speeds, the fastest i have the 924 up to is 120, and it was still going strong for being at 5k+ rpm's, when i was first bringing home the 944, i did open it up, but only had it at 90mph (i wasn't going to screw around in a car that i wasn't sure could handle the speed) and it took noticably longer to get to 90 than the 924, i should have downshifted to 4th, but in the 924 i never would have had to do that since thats where its pulling its most power yanno? i didn't know the difference in tranies at that point.
as to porsches do get noticed and they dont need the neon, i know its lame, i agree, in fact i can't even have it on anyways, blue is illegal (besides the track and parking lots) but how many poeple here think the 924 is really that noticable anyways? i LOVE the car, dont get me wrong, but when u've seen a 944, and how bold it looks, the 924 looks pretty wimpy (especially when i put the two next to one another), thin tires, straight forward body. so i wanted to spruce it up a bit. besides just take into account how many of u would like a 944, over a 924s? same motor, and its faster, but i know u'd still pick the 44 yanno? i dunno i guess that was my reasoning...
oh and there was no funny business on the dyno, i just got the sheet and stated what it told me. i guess it could have been faulty, but i doubt a pro car shop would be off so much yanno?
in my 924s, since it is geared lower, it is a lot easier to get to the higher speeds, the fastest i have the 924 up to is 120, and it was still going strong for being at 5k+ rpm's, when i was first bringing home the 944, i did open it up, but only had it at 90mph (i wasn't going to screw around in a car that i wasn't sure could handle the speed) and it took noticably longer to get to 90 than the 924, i should have downshifted to 4th, but in the 924 i never would have had to do that since thats where its pulling its most power yanno? i didn't know the difference in tranies at that point.
as to porsches do get noticed and they dont need the neon, i know its lame, i agree, in fact i can't even have it on anyways, blue is illegal (besides the track and parking lots) but how many poeple here think the 924 is really that noticable anyways? i LOVE the car, dont get me wrong, but when u've seen a 944, and how bold it looks, the 924 looks pretty wimpy (especially when i put the two next to one another), thin tires, straight forward body. so i wanted to spruce it up a bit. besides just take into account how many of u would like a 944, over a 924s? same motor, and its faster, but i know u'd still pick the 44 yanno? i dunno i guess that was my reasoning...
08-07-2005, 02:58 AM
#131
Three Wheelin'
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lol u guys crack me up. sorry but i spent WAY to much time on installing those noens, do u know how many feet of wire i had to run? way to much... besides you cant see ANY neon bars on the car anyways, so its like they arn't even there, and i never have them on at night, unless some1 asks to see, and thats it, quite litterally. so imo its like they dont even exist! i hope u feel better!
And campeck, when i had first filled the bottle and hand tightend the line, and opended it, it sprayed burning snowflakes onto my hands as i tried to close the bottle! so that day i learned to use a wrench...lol and also, if u used nitrous for ac, you'd burn quite litterally from freezing! haha enjoy!
And campeck, when i had first filled the bottle and hand tightend the line, and opended it, it sprayed burning snowflakes onto my hands as i tried to close the bottle! so that day i learned to use a wrench...lol and also, if u used nitrous for ac, you'd burn quite litterally from freezing! haha enjoy!
08-07-2005, 05:10 AM
#133
Wax On, Wax Off
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Mav, quite frankly, I love the 924S looks better, and having a Turbo S in the family, I like the 924S better as a daily car, and even as a track car... it's much more civilized around town, and on the track, since it's so light, you can just throw the car into a corner, and it'll take it. the turbo, you can definately feel the extra weight...
IMHO, the 924S looks like a rocket ship with the "rat nose" as it's been called. I love the car, and personally, I prefer it to the 944, but I do love them equally.
IMHO, the 924S looks like a rocket ship with the "rat nose" as it's been called. I love the car, and personally, I prefer it to the 944, but I do love them equally.
