Saturn Skyline Forum banner

201 - 220 of 557 Posts

·
Registered
Joined
·
2,246 Posts
Just as a reference, a 1300whp supra couldn't do 200mph in the half mile event. He got to 197.
Supra Cd= 0.32

Solstice Cd= 0.45

Which means that the Solstice has a huge disadvantage - 130 counts or 40% worse aerodynamically. Which means that if a 1300 whp Supra couldn't do it, the Solstice hasn't a chance.

If you want a closer calculation, the frontal area of the Solstice is about 21.4 sq.ft. so the CdA (best way to compare cars as one might have a lower Cd but a higher frontal area) is 9.63

Supra is 6.44.

If anyone is interested the old Fiero was 6.75, not bad but not as good as the Supra (the Fiero also tended to get light in the front at high speeds, which is another consideration if you actually want to try an attain top speed).

Best you get on the street tends to be something like the Acura NSX at 6.13 for modern performance cars. Little cars can sneak into the 5 range - Honda CRX etc. because they have low frontal areas.

Here's a handy list I came across if you are interested:

Vehicle Coefficient of Drag List - EcoModder
 

·
Registered
Joined
·
288 Posts
Supra Cd= 0.32


If anyone is interested the old Fiero was 6.75, not bad but not as good as the Supra (the Fiero also tended to get light in the front at high speeds, which is another consideration if you actually want to try an attain top speed).


Vehicle Coefficient of Drag List - EcoModder
Hello, funny you said that about our beloved Fiero. Heres one with our tilt front end, which gets rid of that lightless at speed. Not bad at 155mph also 128 mph in the 1/4mi plus its ALL Electric powered.Thanks Norm

https://www.youtube.com/watch?v=I6x-zCkYPL0&list=FLaabxB2347u_kOhlw-z2csQ&index=30
https://www.youtube.com/watch?v=fIkIWUOEByQ&list=FLaabxB2347u_kOhlw-z2csQ&index=40
DCPlasmaFierotilt.jpg Photo by normsf | Photobucket
 

·
Registered
Joined
·
2,246 Posts
Yeah, I had one for 20 years - 300 bhp turbo - and it would start to open the headlights at around 120.
 

·
Super Moderator
Joined
·
11,040 Posts
The two big differences here are Im not spending a million bucks building the motor and if it blows I can buy another used motor for under 1000 dollars and build it the way I want. Also I drive my car every day and even though I do drive spirited I'm only running max boost maybe 10% of the time :)
That's basically what I was getting at. You're not putting the money or R&D time into building an engine that can take that kind of punishment regularly and still maintain reliability. You're pushing that engine FAR beyond what it was ever intended to do and I believe you know that. :)

Still can't wait to see what happens.
 

·
Super Moderator
Joined
·
11,040 Posts
Supra Cd= 0.32

Solstice Cd= 0.45

Which means that the Solstice has a huge disadvantage - 130 counts or 40% worse aerodynamically. Which means that if a 1300 whp Supra couldn't do it, the Solstice hasn't a chance.

If you want a closer calculation, the frontal area of the Solstice is about 21.4 sq.ft. so the CdA (best way to compare cars as one might have a lower Cd but a higher frontal area) is 9.63

Supra is 6.44.

If anyone is interested the old Fiero was 6.75, not bad but not as good as the Supra (the Fiero also tended to get light in the front at high speeds, which is another consideration if you actually want to try an attain top speed).

Best you get on the street tends to be something like the Acura NSX at 6.13 for modern performance cars. Little cars can sneak into the 5 range - Honda CRX etc. because they have low frontal areas.

Here's a handy list I came across if you are interested:

Vehicle Coefficient of Drag List - EcoModder
I understand the logic but that doesn't mean the Sky won't top 200 mph.

The Veyron produces under 1100 hp...200 hp less than the Supra you mention. The Veyron has a CdA of 8.02. compared to the 6.44 of the Supra. The Veyron's Cd is a better comparison to the Supra at 0.36 but still worse than the Supra's 0.32.

By your logic, this would mean if the Supra with it's greater power and superior aerodynamics when compared to the Veyron couldn't hit 200 mph, then the Veyron couldn't either yet we all know that's not the case. (This is like the humble bumble bee who, according to the laws of physics as we know them, cannot fly.)

Here is the video from the event. Granted they were limited to half a mile... but they were making quite a bit of power....

https://www.youtube.com/watch?v=IntCzH8kgIk
Damn it man you were posting while I was researching Veyron numbers! LOL

Okay, looking at that video I notice two things. First...This is basically a standing 1/2 mile. If you look at most top speed runs, they're done on a track where the cars have a lot more room to get up to speed than a 1/2 mile. Hell, at Bonneville the timing area is a mile long and the cars are already up to speed when they hit that. Second, from the comments section it looks like the 198mph Supra wasn't set at a high boost level. I have no idea what a "4 iboost" level means but from the tone of the comment it sounds like it isn't very high. I could have that all wrong though.

Basically if RickyD only has a 1/2 mile to get up to speed, he probably won't hit 200 mph. However, if he has more room that than, he could break that number.
 

·
Registered
Joined
·
2,987 Posts
I understand the logic but that doesn't mean the Sky won't top 200 mph.

(snip)


Damn it man you were posting while I was researching Veyron numbers! LOL

Okay, looking at that video I notice two things. First...This is basically a standing 1/2 mile. If you look at most top speed runs, they're done on a track where the cars have a lot more room to get up to speed than a 1/2 mile. Hell, at Bonneville the timing area is a mile long and the cars are already up to speed when they hit that. Second, from the comments section it looks like the 198mph Supra wasn't set at a high boost level. I have no idea what a "4 iboost" level means but from the tone of the comment it sounds like it isn't very high. I could have that all wrong though.

Basically if RickyD only has a 1/2 mile to get up to speed, he probably won't hit 200 mph. However, if he has more room that than, he could break that number.
Agreed. I am saying you will need a LOT of space to get to 200mph.

Iboost 4 is basically setting #4 out of 5 settings. His Iboost 4 is pushing 1100whp. Keep in mind... 8285 CEA precision. That is nearly 3 times the power a stock LNF block can handle.... so getting their with a SC is going to be quite a task. It will be a 100% hairdryer following your "drive for 3 miles to get up to speed and hammer down to get to 200" tactic. Heat soak will be insane.... and you will have to find a place long enough that will let you do that. I hope he does not plan to do this on an open road.
 

·
Super Moderator
Joined
·
11,040 Posts
Agreed. I am saying you will need a LOT of space to get to 200mph.

Iboost 4 is basically setting #4 out of 5 settings. His Iboost 4 is pushing 1100whp. Keep in mind... 8285 CEA precision. That is nearly 3 times the power a stock LNF block can handle.... so getting their with a SC is going to be quite a task. It will be a 100% hairdryer following your "drive for 3 miles to get up to speed and hammer down to get to 200" tactic. Heat soak will be insane.... and you will have to find a place long enough that will let you do that. I hope he does not plan to do this on an open road.
Oh, getting to 200 will be quite the task and take a lot of room...and good weather...and a good road...(I hear Montana's nice.) Heat soak will come into play but it means that he won't be making boost under ideal circumstances. As long as he plans for that and has an IC that is able to take enough heat out of the charge to prevent KR it shouldn't be an issue. Might also want to look into methanol injection to further cool the intake charge and keep cylinder temps down.

Also, thanks for clearing up that IBoost thing. Figured it was something like that but had no idea what the range was. So 4 is still up there...80% of his capability.
 

·
Premium Member
Joined
·
1,811 Posts
Discussion Starter #209 (Edited)
This is true but..

They still produce more heat that a turbocharger in the effect they load the engine rather than just utilize the exhaust gasses.

Either way I look forward to the outcome. I just hope you plan to do the top speed run on a runway somewhere and plan to have a parachute installed on the car in case it gets nutty!
Superchargers are way more efficient then turbos and whatever power it takes to spin them you gain back. The Lysholm like I have and the Whipple twin screws do create heat but not as much as you would think. Also there is no lag time at all. This may not sound like a big deal but think of it this way. I can be 2 car lengths ahead of most turbo cars while they wait the 1-2 seconds trying to get the boost all the way up. I go from 0 to 15psi in less then a second and have full HP by 2400 RPMs. You can get a lot of boost out of a turbo but the power you would get running 20-25 psi I can get at 12-15. Turbos are fine but superchargers are way more fun:thumbs::)
 

·
Premium Member
Joined
·
1,811 Posts
Discussion Starter #210
Thats a Fiero??

Hello, funny you said that about our beloved Fiero. Heres one with our tilt front end, which gets rid of that lightless at speed. Not bad at 155mph also 128 mph in the 1/4mi plus its ALL Electric powered.Thanks Norm

https://www.youtube.com/watch?v=I6x-zCkYPL0&list=FLaabxB2347u_kOhlw-z2csQ&index=30
https://www.youtube.com/watch?v=fIkIWUOEByQ&list=FLaabxB2347u_kOhlw-z2csQ&index=40
DCPlasmaFierotilt.jpg Photo by normsf | Photobucket
They must have changed the back also because Fieros never came with back windows like that. It looks more like a old Supra:confused:
 

·
Premium Member
Joined
·
1,811 Posts
Discussion Starter #211
mmm Not really.

That's basically what I was getting at. You're not putting the money or R&D time into building an engine that can take that kind of punishment regularly and still maintain reliability. You're pushing that engine FAR beyond what it was ever intended to do and I believe you know that. :)

Still can't wait to see what happens.
They will not admit to it but I was told by a GM Engineer that the bottom ends being 4 bolt mains on the 2.4 Ecotec where built to withstand 550 HP. Granted It wont hold that for long periods of time but I'm not talking 5 miles here. :thumbs:
 

·
Premium Member
Joined
·
1,811 Posts
Discussion Starter #212
I'm going to run both

Oh, getting to 200 will be quite the task and take a lot of room...and good weather...and a good road...(I hear Montana's nice.) Heat soak will come into play but it means that he won't be making boost under ideal circumstances. As long as he plans for that and has an IC that is able to take enough heat out of the charge to prevent KR it shouldn't be an issue. Might also want to look into methanol injection to further cool the intake charge and keep cylinder temps down.

Also, thanks for clearing up that IBoost thing. Figured it was something like that but had no idea what the range was. So 4 is still up there...80% of his capability.
The half mile in Houston and the Mile in Beeville. They are both air fields with long run ways. At the mile every car there if they didnt get close to the 150+ mark in the half wouldnt make it. Actually pretty much every car there out weighs our cars by at least 600+ lbs. It takes power, aerodynamics and light weight to go 200 in a mile. Farth then that and weight has nothing to do with it. Once the mass is moving it takes very little to keep it moving. Only drag as speed increases holds you back. Look a the Buggati, that thing weighs 4300lbs!! Thats why it needs to much HP to go 0-6 in 2.9 Sec. :)
 

·
Registered
Joined
·
2,987 Posts
Superchargers are way more efficient then turbos and whatever power it takes to spin them you gain back. The Lysholm like I have and the Whipple twin screws do create heat but not as much as you would think. Also there is no lag time at all. This may not sound like a big deal but think of it this way. I can be 2 car lengths ahead of most turbo cars while they wait the 1-2 seconds trying to get the boost all the way up. I go from 0 to 15psi in less then a second and have full HP by 2400 RPMs. You can get a lot of boost out of a turbo but the power you would get running 20-25 psi I can get at 12-15. Turbos are fine but superchargers are way more fun:thumbs::)
This is the most painful post I think I've read in quite a while. You cant possibly make a more mis-informed statement. Superchargers suffer parasitic loss. Its been documented forever.

If you don't believe me, feel free to Google or read this:

Lose Power To Make Power: ProCharger Parasitic Loss Testing - Dragzine

Cliffs:
It takes a ****load of power to run a blower.

 

·
Super Moderator
Joined
·
11,040 Posts
They will not admit to it but I was told by a GM Engineer that the bottom ends being 4 bolt mains on the 2.4 Ecotec where built to withstand 550 HP. Granted It wont hold that for long periods of time but I'm not talking 5 miles here. :thumbs:
Wouldn't surprise me. Our 3.8s came from the factory with four bolt mains and 240 hp but the bottom ends could handle far more than that. We had some cars pushing over 900 hp through that stock bottom end reliably...

...now the pistons, rods and transmissions...THEY couldn't handle that power.

I have heard though that 400 hp is kind of the safe place to be power wise with the 2.4. Wonder if this means I could push it to 450?

This is the most painful post I think I've read in quite a while. You cant possibly make a more mis-informed statement. Superchargers suffer parasitic loss. Its been documented forever.

If you don't believe me, feel free to Google or read this:

Lose Power To Make Power: ProCharger Parasitic Loss Testing - Dragzine

Cliffs:
It takes a ****load of power to run a blower.

Hmmmm...Something seems off with that.

So if you have an engine that starts at 100 hp, throw 31 lbs of boost at it using that F2 blower, and let's say the engine is now producing 300 hp what you are really saying is that the 31 lbs of boost added 553 hp to that 100 hp engine but 353 hp is being lost turning the blower?

That seems like an extraordinary amount of power from 31 lbs of boost. I take their word for it, they know more about this stuff than I do, but...you ever read or hear something and that little voice in the back of your head starts telling you something just isn't quite right? Yea...

Also, what role does volume play with all this? Anyone know? I know when I went from my M90 to my 2.3 Liter Whipple (which was designed as an upgrade for the M112 found on the Cobra Mustang) that my power profile changed.

With the M90, you got a lot of power down low but as you passed half track on a 1/4 mile pass, the power seemed to go "flat". You didn't pick up much speed on the back half an the car didn't seem to pull the same as it did in the first half of the pass.

With the Whipple, power remained constant throughout the pass. Low end power was still great...better than with the M90 obviously...yet at the top end the car just kept pulling and I would pick up more speed on the back half than I did with the M90. I wasn't the only Grand Prix owner to notice this either. I had a club member drive my car and he mentioned the car just wanted to keep pulling too...and I hadn't told him about that sensation before he tried it.

I always thought this might be because the blower is pushing out a greater volume of air at that boost level and thus could maintain that boost level even when the engine was sustaining higher RPMs like at the end of a pass.
 

·
Premium Member
Joined
·
1,811 Posts
Discussion Starter #215
The reason the numbers look strange is this.

Wouldn't surprise me. Our 3.8s came from the factory with four bolt mains and 240 hp but the bottom ends could handle far more than that. We had some cars pushing over 900 hp through that stock bottom end reliably...

...now the pistons, rods and transmissions...THEY couldn't handle that power.

I have heard though that 400 hp is kind of the safe place to be power wise with the 2.4. Wonder if this means I could push it to 450?



Hmmmm...Something seems off with that.

So if you have an engine that starts at 100 hp, throw 31 lbs of boost at it using that F2 blower, and let's say the engine is now producing 300 hp what you are really saying is that the 31 lbs of boost added 553 hp to that 100 hp engine but 353 hp is being lost turning the blower?

That seems like an extraordinary amount of power from 31 lbs of boost. I take their word for it, they know more about this stuff than I do, but...you ever read or hear something and that little voice in the back of your head starts telling you something just isn't quite right? Yea...

Also, what role does volume play with all this? Anyone know? I know when I went from my M90 to my 2.3 Liter Whipple (which was designed as an upgrade for the M112 found on the Cobra Mustang) that my power profile changed.

With the M90, you got a lot of power down low but as you passed half track on a 1/4 mile pass, the power seemed to go "flat". You didn't pick up much speed on the back half an the car didn't seem to pull the same as it did in the first half of the pass.

With the Whipple, power remained constant throughout the pass. Low end power was still great...better than with the M90 obviously...yet at the top end the car just kept pulling and I would pick up more speed on the back half than I did with the M90. I wasn't the only Grand Prix owner to notice this either. I had a club member drive my car and he mentioned the car just wanted to keep pulling too...and I hadn't told him about that sensation before he tried it.

I always thought this might be because the blower is pushing out a greater volume of air at that boost level and thus could maintain that boost level even when the engine was sustaining higher RPMs like at the end of a pass.
Grasshopper,,,,:) First off that website is talking about Prochargers NOT superchargers. Prochargers are basically belt driven turbo chargers that are geared to spin fast. Not even close.
Turbos run extremely hot as well. Open the hood on a turbo car at night after running it even a little hard and the turbo will be glowing cherrie red. Unless you run a really big turbo which would have major lag problems. A screw type S/C will out perform a turbo pound for pound any day of the week. On the website it showed 18lbs of boost at 45991 RPM's. The Lysholm 1.6 has a red line of like 17-18K. I will be making 15lbs of boost at around 13000 so how do you figure a turbo is more effecient? If I ran 20-25 lbs of boost I wouldnt be looking at 300 HP I'd be looking at around 500HP.

How many lbs of boost and HP were you running Robo?

In theory, a turbocharger is more efficient because it is using the "wasted" energy in the exhaust stream for its power source. On the other hand, a turbocharger causes back pressure in the exhaust system and tends to provide less boost until the engine is running at higher RPMs.
 

·
Registered
Joined
·
2,987 Posts
I am not going to argue with someone who doesn't even understand the basics. You can find out in the end on your own. Its going to be a heat pump like all twin screw setups. As top fuel cars have shown, you get tons of heat and parasitic loss with a screw type SC.

Here is a fact from Wiki about Top fuel cars with twin screw/roots superchargers on top fuel cars.

Superchargers

The supercharger can be a 14-71 type Roots blower although Screw blowers are also sometimes used. It has twisted lobes and is driven by a toothed belt. The supercharger is slightly offset to the rear to provide an even distribution of air. Absolute manifold pressure is usually 3.8-4.5 bar (56-66 PSI), but up to 5.0 bar (74 PSI) is possible. The manifold is fitted with a 200 psi burst plate. Air is fed to the compressor from throttle butterflies with a maximum area of 65 sq. in (419.35 cm²). At maximum pressure, it takes approximately 600 horsepower (450 kW) to drive the supercharger.
Source: Top Fuel - Wikipedia, the free encyclopedia
 

·
Super Moderator
Joined
·
11,040 Posts
I am not going to argue with someone who doesn't even understand the basics. You can find out in the end on your own. Its going to be a heat pump like all twin screw setups. As top fuel cars have shown, you get tons of heat and parasitic loss with a screw type SC.

Here is a fact from Wiki about Top fuel cars with twin screw/roots superchargers on top fuel cars.

Superchargers

The supercharger can be a 14-71 type Roots blower although Screw blowers are also sometimes used. It has twisted lobes and is driven by a toothed belt. The supercharger is slightly offset to the rear to provide an even distribution of air. Absolute manifold pressure is usually 3.8-4.5 bar (56-66 PSI), but up to 5.0 bar (74 PSI) is possible. The manifold is fitted with a 200 psi burst plate. Air is fed to the compressor from throttle butterflies with a maximum area of 65 sq. in (419.35 cm²). At maximum pressure, it takes approximately 600 horsepower (450 kW) to drive the supercharger.
Source: Top Fuel - Wikipedia, the free encyclopedia
How does an engine know the air that is coming into it came from a Supercharger or a Turbocharger? Answer: it doesn't. Boost is Boost to an engine. More air is more air.

Yes a turbo and a supercharger both pushing 20 psi are still pushing 20 psi. The only way to tell which one is better on that engine's setup is to dyno the car at the wheels. Whichever setup produces better numbers, that's the overall better setup.

For off the line power like an NHRA dragster, the Supercharger's instant boost is the clear favorite. For Indy car style racing where the driver can keep the engine up high in it's RPM range and keep the turbo spooled, the Turbo wins out for it's lack of Parasitic drag, lighter weight, and lack of a belt that can break mid race.

So while a supercharger may take 600 hp to be turned, it is obviously adding a lot more than 600 hp to an engine because I have yet to see a car's hp rating DROP after adding a supercharger. The logic then dictates that if it takes 500 hp to make the amount of boost that increases an engines power from 100 to 300 hp...then the blower must be adding 700 hp to the engine for a net gain of 200 hp. To make a turbo "more efficient" than that, you would need a to add the same or more hp with the same amount of boost.

You also are making it sound like turbos don't get heat soaked. They are ran off the exhaust gas...their casings get really hot...sometimes red hot...far hotter than a supercharger's casing. That heat does get transferred through the case to the intake track and heat the air charge. The more RPMs you turn, the more exhaust gas passes through that turbo and the more heat is transferred to its case.

I ran a twin screw setup on my Grand Prix and believe me, I didn't have heat issues. The intercooler I had was more than capable of keeping the intake charge cool for spirited runs up to and over 140 mph. And my system wasn't even close to maxed out. As a matter of fact, the twin screw ran cooler overall than the roots it replaced. (Both had a boost bypass valve for cruising.) Not saying you're wrong about my compressor or blower needing power to make power...but you make it sound like a twin screw blower setup is crap and that I'll never agree with.
 

·
Registered
Joined
·
2,987 Posts
How does an engine know the air that is coming into it came from a Supercharger or a Turbocharger? Answer: it doesn't. Boost is Boost to an engine. More air is more air.

Yes a turbo and a supercharger both pushing 20 psi are still pushing 20 psi. The only way to tell which one is better on that engine's setup is to dyno the car at the wheels. Whichever setup produces better numbers, that's the overall better setup.

For off the line power like an NHRA dragster, the Supercharger's instant boost is the clear favorite. For Indy car style racing where the driver can keep the engine up high in it's RPM range and keep the turbo spooled, the Turbo wins out for it's lack of Parasitic drag, lighter weight, and lack of a belt that can break mid race.

So while a supercharger may take 600 hp to be turned, it is obviously adding a lot more than 600 hp to an engine because I have yet to see a car's hp rating DROP after adding a supercharger. The logic then dictates that if it takes 500 hp to make the amount of boost that increases an engines power from 100 to 300 hp...then the blower must be adding 700 hp to the engine for a net gain of 200 hp. To make a turbo "more efficient" than that, you would need a to add the same or more hp with the same amount of boost.

You also are making it sound like turbos don't get heat soaked. They are ran off the exhaust gas...their casings get really hot...sometimes red hot...far hotter than a supercharger's casing. That heat does get transferred through the case to the intake track and heat the air charge. The more RPMs you turn, the more exhaust gas passes through that turbo and the more heat is transferred to its case.

I ran a twin screw setup on my Grand Prix and believe me, I didn't have heat issues. The intercooler I had was more than capable of keeping the intake charge cool for spirited runs up to and over 140 mph. And my system wasn't even close to maxed out. As a matter of fact, the twin screw ran cooler overall than the roots it replaced. (Both had a boost bypass valve for cruising.) Not saying you're wrong about my compressor or blower needing power to make power...but you make it sound like a twin screw blower setup is crap and that I'll never agree with.
I am not saying they are crap or don't have their place. In the drag world, the SC is formidable as it makes power thought the RPM range. This leads to good ET's. Along with a properly sized cooling system, they are great.

However on a LNF trying to hit 200mph, a turbo is better suited... or at a minimum, a centrifugal supercharger. He's not trying to get there form a stop... so you want top end power... which a twin screw will eat up.

I guess we will see what happens when the car is finished and he makes his run.
 
201 - 220 of 557 Posts
Top