turbofabricator
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Then just turn the NITROUS up instead??
Time to go Stage II!
- Thread starter Alky V6
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Now you're talkin'! That's still an option with the afterburner side of the system.Then just turn the NITROUS up instead??
turbofabricator
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In my old "job" we would go through 150 pounds of N2O in about 5 minutes. Filling the five 30 lb nitrous bottles was dang near a full time job. Custom nitrous and fuel valves to flow that much in a single stage. (800-900hp shot just to get the boat out of the turn.) Nothing wrong with nitrous. Just ALOT wrong with too much nitrous. Here's an example of too much nitrous. (by the way, this is a 6" diameter piston. It was killed because the nitrous valve stuck open. Fuel valve shut. Not a good day. Windowed the block, too. Also burned a nice hole through the cylinder head and caught the engine cowling on fire.)
Do be careful with that stuff, Donnie. (hate to see it melt your kool headers off.)
Do be careful with that stuff, Donnie. (hate to see it melt your kool headers off.)
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That's one of the beauties about my nitrous system. The shot, being as large as it is relative to the power that's generated in the cylinder when the system is off, will not damage the engine if one or the other solenoid should happen to fail to activate, or stick open. Ask me how I know this for sure.
Think about it. What happens when you have a super rich methanol mixture in the cylinder? What happens when you have a super lean methanol mixture in the cylinder?
Think about it. What happens when you have a super rich methanol mixture in the cylinder? What happens when you have a super lean methanol mixture in the cylinder?
With the sort of cam specs I plan to use, I wonder how much advantage there would be to install an aerodynamic device into the primaries to lessen exhaust reversion flow?
There's already going to be a little bit of a mismatch in ID size between the header primary size and the exhaust port.
There's already going to be a little bit of a mismatch in ID size between the header primary size and the exhaust port.
turbofabricator
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Liquid nitrogen is just plain TOO cold unless you only race in Arizona or New Mexico. Any humidity will freeze up the intercooler solid. I use liquid nitrogen frequently and have to suit up in protective gear so it doesn't burn instantly. I've immersed ripe bannanas in it and after a few seconds pull it out and throw it on the floor and it SHATTERS in a bazillion pieces. (DON'T do that! The mess is AWFUL to clean up a few minutes later. GOO everywhere!) We've frozen all kinds of interesting stuff. But I'm gonna claim the fifth on this issue, though.
CO2 or nitrous would be a better choice. Jim D'Alesandro use to use CO2 on his intercooler. It made a TON of power. (it picked up his 60 ft. times a BUNCH!!!!! 
Especially when the CO2 vapor caused to beams to stay lit until the rear tires blew it away and it started the timers.
CO2 or nitrous would be a better choice. Jim D'Alesandro use to use CO2 on his intercooler. It made a TON of power. (it picked up his 60 ft. times a BUNCH!!!!! Especially when the CO2 vapor caused to beams to stay lit until the rear tires blew it away and it started the timers.Interesting. The wheels are turning.Liquid nitrogen is just plain TOO cold unless you only race in Arizona or New Mexico. Any humidity will freeze up the intercooler solid. I use liquid nitrogen frequently and have to suit up in protective gear so it doesn't burn instantly. I've immersed ripe bannanas in it and after a few seconds pull it out and throw it on the floor and it SHATTERS in a bazillion pieces. (DON'T do that! The mess is AWFUL to clean up a few minutes later. GOO everywhere!) We've frozen all kinds of interesting stuff. But I'm gonna claim the fifth on this issue, though.
I'm going to drop the anti-reversion device idea. I don't think there would be any gains there.
Running the single turbo, the exhaust collectors are going to join at a Y pipe right at the turbo. With a V6 configuration, it might be advantageous to put a wall in the Y pipe to split it so that each bank of cylinders is separated. I'm already running a split turbine housing.
Valve events are happening every 120 degrees of crankshaft rotation. The cylinder firings are bank to bank. That means an exhaust pulse is created, bank to bank every 120 degrees. As a piston is beginning to pump exhaust gases from one cylinder, the exhaust valve is opening on another cylinder on the opposite bank of cylinders. How does that new exhaust pulse affect the other cylinder on the other bank that is about 60+ degrees ABDC into pumping the exhaust gases out of it?
Valve events are happening every 120 degrees of crankshaft rotation. The cylinder firings are bank to bank. That means an exhaust pulse is created, bank to bank every 120 degrees. As a piston is beginning to pump exhaust gases from one cylinder, the exhaust valve is opening on another cylinder on the opposite bank of cylinders. How does that new exhaust pulse affect the other cylinder on the other bank that is about 60+ degrees ABDC into pumping the exhaust gases out of it?
I'm going to make the Y pipe at the turbine housing simple and open. No separating of the cylinder banks. The only advantage to separating the banks would be spool up time. With the nitrous, I don't need to concern myself with that. I'd rather give the exhaust flow from either bank as much turbine area as possible to escape as quickly as possible, rather than take the chance that separating the banks at the Y pipe will create an exhaust restriction at the turbine housing.
Dusty. I thought you preferred twin turbos? A single turbo? Why?
Dusty Bradford
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Because a single can make 2400 and that's all I want. If I ever want 3000 I'll swap to twins.
Other issues that keep me with the single. Cost, weight. Another turbo is another 70lbs on the nose of an already heavy car. My focus now is not on more power, but more chassis. I couldn't use anywhere near the power I could make with my old chassis set-up. I can now weigh 3250 so I was over 200# heavy for my class. I need to go 1.17-1.22 60' times and doing this at 3450# isn't easy. So rather than spending money on power I'm getting it down to weight. I need to go something like 1.18-3.08-4.50 at 165. So getting the chassis to handle the power early in the run is the goal.
How much power do you think it takes to do 1.23-1.24s in the 60 with a 3300lb car and 10.5w tires?
Do you think starting the launch at 550bhp and ramping it to 1280bhp by the 60' might do it?
Dusty Bradford
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I have never even took into consideration starting line hp so I can't tell you how much to start with.
I can tell you this. I run a radial which takes less hp to run fast to the 60' than a slick but the radial is a totally different animal from a chassis perspective. You have to "hit" the slick with more power than you do a radial to get the same 60'. This is due to the sidewall flex. The slick eats up some power. If you can ramp power to 1200hp by 1.2 seconds the car should 60' in the low 1.2's. This Mustang I race often will see full boost from the 80mm turbo before the 60' marker if that gives you an indication of what it takes to go 1.24 at 3260#. 1.0 seconds to be exact. If I were to put a slick on it I would have to increase launch rpm by 400 to get the same effect. In other words, I don't know if it's making any more hp from raising the launch rpm and the boost is the same but it's what the slick needs to equal the 60' performance.
I can tell you this. I run a radial which takes less hp to run fast to the 60' than a slick but the radial is a totally different animal from a chassis perspective. You have to "hit" the slick with more power than you do a radial to get the same 60'. This is due to the sidewall flex. The slick eats up some power. If you can ramp power to 1200hp by 1.2 seconds the car should 60' in the low 1.2's. This Mustang I race often will see full boost from the 80mm turbo before the 60' marker if that gives you an indication of what it takes to go 1.24 at 3260#. 1.0 seconds to be exact. If I were to put a slick on it I would have to increase launch rpm by 400 to get the same effect. In other words, I don't know if it's making any more hp from raising the launch rpm and the boost is the same but it's what the slick needs to equal the 60' performance.
I think 60' does not relate to hp as much as it does torque. I'm a big nerd and I like simple physics, so here goes some more math.
A couple equations for motion.
x=1/2(v0+v1)t
a=(v1-v0)/t
x = distance (60ft.)
v0 = initial velocity (0 ft/s)
v1 = velocity at 60' (unknown)
t = time (1.23 seconds)
to use these formulas we have to assume constant acceleration. Constant acceleration is best case. Assuming you don't shift in the 60' and you hit the tires hard enough to leave good, it's a good assumption to start with.
First we have to find v1
x=1/2(v0+v1)t
60=1/2(0+v1)1.23
v1= 97 ft/s (66mph)
If constant acceleration were not true, this number would be higher.
now we can find acceleration
a=(v1-v0)/t
a=(97-0)/1.23
a= 78 ft/s^2
1 g is 32.2 ft/s^2
78 ft/s^2 = 2.42g's
force = mass * acceleration
If we converted everything to metric units the math would make more sense, but ultimately to get the force required to accelerate the car, we multiply the weight by the number of g's of acceleration.
f = 3300lbs. * 2.42g's = 7993 lbs.
To get torque at the axle muliply by the 1/2 the tire diameter.
T = 7993 lb * 29 in./2
T= 115909 in lb = 9659 ft. lb. (I have no idea whether a 10.5w with 3300lbs. on it can handle this acceleration)
If you have a 3.73 rear gear, 2.48 first gear and 2:1 torque multiplication in the converter that works out to 522 ft.lb at the flywheel constant or average throughout the 60'. This number is a little low because it doesn't account for accelerting the driveline parts and other rotating masses. The other issue is that as the rpm increases the torque multiplication in the converter decreases so the required torque at the flywheel increases. Assuming the conveter goes 1.2:1 in the 60', the torque required goes to 870 ft. lb. You probably have a better idea about these conveter numbers for your car than I do.
If you took the rpm you leave at and rpm that nets v1=66 mph at the 60', you could use those two rpms to get hp.
A couple equations for motion.
x=1/2(v0+v1)t
a=(v1-v0)/t
x = distance (60ft.)
v0 = initial velocity (0 ft/s)
v1 = velocity at 60' (unknown)
t = time (1.23 seconds)
to use these formulas we have to assume constant acceleration. Constant acceleration is best case. Assuming you don't shift in the 60' and you hit the tires hard enough to leave good, it's a good assumption to start with.
First we have to find v1
x=1/2(v0+v1)t
60=1/2(0+v1)1.23
v1= 97 ft/s (66mph)
If constant acceleration were not true, this number would be higher.
now we can find acceleration
a=(v1-v0)/t
a=(97-0)/1.23
a= 78 ft/s^2
1 g is 32.2 ft/s^2
78 ft/s^2 = 2.42g's
force = mass * acceleration
If we converted everything to metric units the math would make more sense, but ultimately to get the force required to accelerate the car, we multiply the weight by the number of g's of acceleration.
f = 3300lbs. * 2.42g's = 7993 lbs.
To get torque at the axle muliply by the 1/2 the tire diameter.
T = 7993 lb * 29 in./2
T= 115909 in lb = 9659 ft. lb. (I have no idea whether a 10.5w with 3300lbs. on it can handle this acceleration)
If you have a 3.73 rear gear, 2.48 first gear and 2:1 torque multiplication in the converter that works out to 522 ft.lb at the flywheel constant or average throughout the 60'. This number is a little low because it doesn't account for accelerting the driveline parts and other rotating masses. The other issue is that as the rpm increases the torque multiplication in the converter decreases so the required torque at the flywheel increases. Assuming the conveter goes 1.2:1 in the 60', the torque required goes to 870 ft. lb. You probably have a better idea about these conveter numbers for your car than I do.
If you took the rpm you leave at and rpm that nets v1=66 mph at the 60', you could use those two rpms to get hp.
Dusty Bradford
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I don't. But from other data logs of cars like this the G's are 1.8-2.0. Something in the 1.17 60' is 2.2-2.4
I would think that the g force would start out high, say 2.2 at the hit of the launch, ramp down as the car rolled out and torque multiplication from the torque converter waned. Then, it might level out or even increase just a little as the engine found peak torque, then would again ramp down to say 1.5 by the 60'. MPH at about 57 at the 60'.
Tire slip with the slicks would also have to be accounted for. Up to 21% slippage at some point during the launch.
For any calculating with a slick, tire radius change at the launch would also have to be taken into consideration. Which may be why you find you need more rpm at the launch with the slick to do the same 60' as you would with the drag radial. The crushed sidewall of the slick effectively lowers your overall starting line gear ratio. The lower effective gear ratio calls for a higher rpm to produce the same mph.
Tire slip with the slicks would also have to be accounted for. Up to 21% slippage at some point during the launch.
For any calculating with a slick, tire radius change at the launch would also have to be taken into consideration. Which may be why you find you need more rpm at the launch with the slick to do the same 60' as you would with the drag radial. The crushed sidewall of the slick effectively lowers your overall starting line gear ratio. The lower effective gear ratio calls for a higher rpm to produce the same mph.
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