1,000+ horsepower 928S4 picture
06-02-2003, 01:07 PM
#46
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The turbo is typically more efficient and does not heat the air as much as a blower. Looks like these centrifugal units are pretty good though. I remember hearing something like 50% efficiency on the roots style blowers, compared to high 60s to low 70s on the turbochargers.
There are multiple ways to skin this cat. I would assume the blower is preferred in drag racing because you have boost immediately, it is a mechanical line to line connection, whereas with the turbo you have a compressible fluid doing the driving.
There are multiple ways to skin this cat. I would assume the blower is preferred in drag racing because you have boost immediately, it is a mechanical line to line connection, whereas with the turbo you have a compressible fluid doing the driving.
06-02-2003, 01:56 PM
#47
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Top Fuel dragster facts:
-One Dragster's 500-inch (Chrysler) Hemi engine makes more horsepower then the first 8 rows at Daytona.
-Top Fuel Engines ONLY turn 540 revolutions from light to light!
-Under full throttle, a dragster engine consumes 1 1/2 gallons of nitro PER SECOND, the same rate of fuel consumption as a fully loaded 747, but with 4 times the energy volume.
-The supercharger takes more power to drive then a stock hemi makes.
-Even with nearly 3000 CFM of air being rammed in by the supercharger on overdrive, the fuel mixture is compressed into nearly-solid form before ignition. Cylinders run on the verge of hydraulic lock.
-Dual Magnetos apply 44 amps to each spark plug. This is the output of an
arc welder in each cylinder.
-At stoichiometric(exact)1.7:1 air/fuel mixture(for nitro), the flame
front of nitromethane measures 7050ºF.
-Nitromethane burns yellow. The spectacular white flame seen above the
stacks at night is raw burning hydrogen, dissociated from atmospheric
water vapor by the searing exhaust gases.
-Spark Plug electrodes are totally consumed during a pass. After 1/2 way,
the engine is dieseling from compression-plus the glow of exhaust valves
at 1400ºF. The engine can only be shut down by cutting of it's fuel flow.
-If spark momentarily fails early in the run, unburned nitro builds up in
those cylinders and then explodes with a force that can blow cylinder
heads off the block in pieces, or blow the block in 1/2.
-Dragsters twist the crank(torsionally)so far(20º in the big end of the
track)that sometimes cam lobes are ground offset from front to rear to
re-phase the valve timing somewhere closer to synchronization with the
pistons.
-To exceed 300mph in 4.5 seconds dragsters must accelerate at an average of over 4Gs. But in reaching 200mph well before 1/2 track, launch
acceleration is closer to 8Gs.
-Drivers shut off before the finish line, or even dual parachutes will
not stop the car.
-If all the equipment is paid off, the crew worked for free, and for once
NOTHING BLOWS UP, each run costs $1000.00 per second.
-Dragsters reach over 300 miles per hour before you have read this
sentence.
-One Dragster's 500-inch (Chrysler) Hemi engine makes more horsepower then the first 8 rows at Daytona.
-Top Fuel Engines ONLY turn 540 revolutions from light to light!
-Under full throttle, a dragster engine consumes 1 1/2 gallons of nitro PER SECOND, the same rate of fuel consumption as a fully loaded 747, but with 4 times the energy volume.
-The supercharger takes more power to drive then a stock hemi makes.
-Even with nearly 3000 CFM of air being rammed in by the supercharger on overdrive, the fuel mixture is compressed into nearly-solid form before ignition. Cylinders run on the verge of hydraulic lock.
-Dual Magnetos apply 44 amps to each spark plug. This is the output of an
arc welder in each cylinder.
-At stoichiometric(exact)1.7:1 air/fuel mixture(for nitro), the flame
front of nitromethane measures 7050ºF.
-Nitromethane burns yellow. The spectacular white flame seen above the
stacks at night is raw burning hydrogen, dissociated from atmospheric
water vapor by the searing exhaust gases.
-Spark Plug electrodes are totally consumed during a pass. After 1/2 way,
the engine is dieseling from compression-plus the glow of exhaust valves
at 1400ºF. The engine can only be shut down by cutting of it's fuel flow.
-If spark momentarily fails early in the run, unburned nitro builds up in
those cylinders and then explodes with a force that can blow cylinder
heads off the block in pieces, or blow the block in 1/2.
-Dragsters twist the crank(torsionally)so far(20º in the big end of the
track)that sometimes cam lobes are ground offset from front to rear to
re-phase the valve timing somewhere closer to synchronization with the
pistons.
-To exceed 300mph in 4.5 seconds dragsters must accelerate at an average of over 4Gs. But in reaching 200mph well before 1/2 track, launch
acceleration is closer to 8Gs.
-Drivers shut off before the finish line, or even dual parachutes will
not stop the car.
-If all the equipment is paid off, the crew worked for free, and for once
NOTHING BLOWS UP, each run costs $1000.00 per second.
-Dragsters reach over 300 miles per hour before you have read this
sentence.
06-02-2003, 02:47 PM
#48
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Pete,
Interesting stuff, but:
===========================================
"Dual Magnetos apply 44 amps to each spark plug. This is the output of an arc welder in each cylinder"
Don't magnetos rely on a magnetic field to generate the spark off the high tension wire? Where do you get 44 amps? Anyway 44 amps times 60 kilovolts would be over two million watts, which would be enough of a lightning bolt to vaporize the entire dragster!
===========================================
"Drivers shut off before the finish line, or even dual parachutes will not stop the car."
Why don't they just pick a strip with more space after the finish line? Wouldn't shutting off before the finish line be counterproductive???
===========================================
;-)
Interesting stuff, but:
===========================================
"Dual Magnetos apply 44 amps to each spark plug. This is the output of an arc welder in each cylinder"
Don't magnetos rely on a magnetic field to generate the spark off the high tension wire? Where do you get 44 amps? Anyway 44 amps times 60 kilovolts would be over two million watts, which would be enough of a lightning bolt to vaporize the entire dragster!
===========================================
"Drivers shut off before the finish line, or even dual parachutes will not stop the car."
Why don't they just pick a strip with more space after the finish line? Wouldn't shutting off before the finish line be counterproductive???
===========================================
;-)
06-02-2003, 03:39 PM
#49
Drifting
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My understanding is that they initially allowed turbos, but a privateer turbo car started smoking the big sponsored cars. Just like NASCAR, they banned the turbos under the veil of "fair" competition. Besides, turbos are quieter, and do not look or sound as impressive as a blown car. So, even though getting the fastest car is "supposedly" the goal in racing, if that was truly the case, we would see more jet cars, more turbo cars, and more multi-engined cars. They made rules and restrictions in NHRA, just like in NASCAR, to keep the cars more equal, for more exciting head-to-head racing. Same thing happened in other racing series, with the Audi AWD cars, the turbos in Indy cars, etc...
I just wished they allowed anything, and then all the other race cars would have to adapt, and use AWD, turbos, etc, and then whatever is fastest would become standard, and it would all trickle down to the consumer...
They had a lot of bans on wing sizes, underbody tunnels and ground effects in some racing as well...
Think about it...
The Porsche 917's did something like 230MPH at LeMans.
That was decades ago.
The cars now could be doing 300MPH, if weren't for restrictions to keep speeds down...
I just wished they allowed anything, and then all the other race cars would have to adapt, and use AWD, turbos, etc, and then whatever is fastest would become standard, and it would all trickle down to the consumer...
They had a lot of bans on wing sizes, underbody tunnels and ground effects in some racing as well...
Think about it...
The Porsche 917's did something like 230MPH at LeMans.
That was decades ago.
The cars now could be doing 300MPH, if weren't for restrictions to keep speeds down...
06-02-2003, 03:59 PM
#50
Administrator - "Tyson"
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</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by bcdavis:
<strong>
I just wished they allowed anything, and then all the other race cars would have to adapt,</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">I cannot wait until July....Road America BRIC. Can-Am Thunder. Its making the hair on my neck stand up as I sit here! In case you guys-and gals were not aware, one of the 917-30's has been there the past few years running with the shadow's and McLarens of yesterday. That car is so fast and quiet its scary.
This is how you do twin turbo's. I still laugh at the "claimed" power rating of 1100hp.
<img src="http://www.erik27.com/chicago/91730.jpg" alt=" - " />
<strong>
I just wished they allowed anything, and then all the other race cars would have to adapt,</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">I cannot wait until July....Road America BRIC. Can-Am Thunder. Its making the hair on my neck stand up as I sit here! In case you guys-and gals were not aware, one of the 917-30's has been there the past few years running with the shadow's and McLarens of yesterday. That car is so fast and quiet its scary.
This is how you do twin turbo's. I still laugh at the "claimed" power rating of 1100hp.
<img src="http://www.erik27.com/chicago/91730.jpg" alt=" - " />
07-02-2003, 03:18 PM
#51
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A note to Z,
great work there,
On your blue car I see a hose going into the top of the oil filler cap, I assume that's for crankcase venting. How is that plumbed in? Are there other vacuum issues you've come across? I'm considering buying system/kit. Do you have any recommendations?
thanks,
mike
great work there,
On your blue car I see a hose going into the top of the oil filler cap, I assume that's for crankcase venting. How is that plumbed in? Are there other vacuum issues you've come across? I'm considering buying system/kit. Do you have any recommendations?
thanks,
mike
07-02-2003, 03:50 PM
#52
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Originally posted by CRUSMSL:
On your blue car I see a hose going into the top of the oil filler cap, I assume that's for crankcase venting. How is that plumbed in?
On your blue car I see a hose going into the top of the oil filler cap, I assume that's for crankcase venting. How is that plumbed in?
http://forums.rennlist.com/cgi-bin/r...=007189#000024
Are there other vacuum issues you've come across?
I'm considering buying system/kit. Do you have any recommendations?
Last edited by Z; 07-19-2003 at 06:29 PM.
07-02-2003, 07:53 PM
#54
Nordschleife Master
Somebody correct me.
There are three diffrent types of super chargers. Roots, twin screw, and centrifical.
Roots is cheap, effective, but inefficent. Like under 60% efficency most of the time.
Centrifical does not provide a constance boost, but is cheap and efficent, nearly always over 60%
Twin screw is efective, with constant accrost the range boost, highly efficent, but expensive. Thus not to common.
They're all powered by a belt to the crank shaft, and free the exaust up for tuneing to has high a level as you want. Full race headers, free flowing exaust, it's an open feild. The belt has around a 95% or better efficency of transfering the power form the crank.
Turbos are of one type, a turbine attached to a centrifical type blower. The blower has a high efficency, as does the turbine. I needs no power from the crank shaft, BUT requires power from the exaust. The exaust can't realy be tuned, and the turbo creates back pressure, so your loseing exaust schavageing, and the corisponding power there in. You also have a bit of turbo lag, no matter what you do, the only question is is it enough to bother you. And finaly, you have to do the plumbing for the exaust.
Am I getting this correct?
There are three diffrent types of super chargers. Roots, twin screw, and centrifical.
Roots is cheap, effective, but inefficent. Like under 60% efficency most of the time.
Centrifical does not provide a constance boost, but is cheap and efficent, nearly always over 60%
Twin screw is efective, with constant accrost the range boost, highly efficent, but expensive. Thus not to common.
They're all powered by a belt to the crank shaft, and free the exaust up for tuneing to has high a level as you want. Full race headers, free flowing exaust, it's an open feild. The belt has around a 95% or better efficency of transfering the power form the crank.
Turbos are of one type, a turbine attached to a centrifical type blower. The blower has a high efficency, as does the turbine. I needs no power from the crank shaft, BUT requires power from the exaust. The exaust can't realy be tuned, and the turbo creates back pressure, so your loseing exaust schavageing, and the corisponding power there in. You also have a bit of turbo lag, no matter what you do, the only question is is it enough to bother you. And finaly, you have to do the plumbing for the exaust.
Am I getting this correct?
07-02-2003, 08:48 PM
#55
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Originally posted by Shmurzik:
A quick question: is there any advantages/disadvantages in supercharging an automatic or a manual transmission-equipped 928? Thank you.
A quick question: is there any advantages/disadvantages in supercharging an automatic or a manual transmission-equipped 928? Thank you.
Last edited by Z; 07-19-2003 at 06:31 PM.
07-02-2003, 08:51 PM
#56
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Originally posted by ViribusUnits:
Am I getting this correct?
Am I getting this correct?
Last edited by Z; 07-19-2003 at 06:32 PM.
07-02-2003, 10:23 PM
#57
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There was a question about how 928s are classed in PCA Club Racing.
GT2 is for 3.4 liter or larger motored NA cars, GT1 is for 3.4 liter or larger motored turbocharged cars. I don't find a rule to mention supercharging, but would guess it would be treated as GT1.
I haven't seen a drastic difference in GT1 to GT2 lap times at the tracks I run, so switching classes wouldn't be the reason to stop for me.
Personally, I would be very willing to consider running a forced induction motor, particularly if the cost was lower. Of course the NA motors have been proven on the track in race conditions, and forced induction motors have not. I appreciate and respect those who follow unproven paths, but the cost can be high...
Anyone that wants to donate a supercharged motor for testing, I will be happy to put it in my racecar and provide the results. Currently, I only get beat on the straights, not in the corners.... <a href="http://www.928racing.net/StanShawRacecar.htm" target="_blank">http://www.928racing.net/StanShawRacecar.htm</a>
PCA Club Racing rules can be found at <a href="http://www.pca.org/pca/clubrace/docs/pca_rules_2003.pdf" target="_blank">http://www.pca.org/pca/clubrace/docs/pca_rules_2003.pdf</a>
GT2 is for 3.4 liter or larger motored NA cars, GT1 is for 3.4 liter or larger motored turbocharged cars. I don't find a rule to mention supercharging, but would guess it would be treated as GT1.
I haven't seen a drastic difference in GT1 to GT2 lap times at the tracks I run, so switching classes wouldn't be the reason to stop for me.
Personally, I would be very willing to consider running a forced induction motor, particularly if the cost was lower. Of course the NA motors have been proven on the track in race conditions, and forced induction motors have not. I appreciate and respect those who follow unproven paths, but the cost can be high...
Anyone that wants to donate a supercharged motor for testing, I will be happy to put it in my racecar and provide the results. Currently, I only get beat on the straights, not in the corners.... <a href="http://www.928racing.net/StanShawRacecar.htm" target="_blank">http://www.928racing.net/StanShawRacecar.htm</a>
PCA Club Racing rules can be found at <a href="http://www.pca.org/pca/clubrace/docs/pca_rules_2003.pdf" target="_blank">http://www.pca.org/pca/clubrace/docs/pca_rules_2003.pdf</a>
