Roots or Turbo?
12-09-2012, 07:10 PM
#21
Team Owner
Odds are pretty good the LT4 will make 750hp or so. A Rotrex is 3-5% more efficient so the peak power would be slightly higher. A turbo could probably make close to 800hp. Less than 50hp on top of 750hp going from Rotrex to turbo might be worth the tradeoffs to you, but not to me. In fact, at 750hp I wouldn't worry at all about getting more power, but rather HOW to make it in a more civilized manner.
Turbos are fantastic for A to B cars. 1.4L turbo diesels make sense. Maybe that way the gas savings vs. other FI will be enough to service those turbines when they blow up or blow up something else.
Turbos are fantastic for A to B cars. 1.4L turbo diesels make sense. Maybe that way the gas savings vs. other FI will be enough to service those turbines when they blow up or blow up something else.
12-09-2012, 07:40 PM
#22
Le Mans Master
Thread Starter
12-09-2012, 07:56 PM
#24
Safety Car
"When first announced, McLaren claimed that it would have a higher horsepower to carbon dioxide emission ratio than any internal-combustion engine available at the time."
That's what I really want, a supercar that farts lightly. Oh, and can go over a speed bump without messing my hairdo. If only there was a competitor to show how a supercar should feel and sound... hint 458.
12-09-2012, 08:07 PM
#25
Le Mans Master
Thread Starter
The problem is!
The ZR1 is top heavy and several of it performance numbers have been beat by the centennial Z06 so I don't need a turbo to start with. The roots produces low range torque and turbos mid... Go figure!
Last edited by johnglenntwo; 12-09-2012 at 08:16 PM.
12-09-2012, 08:11 PM
#26
Le Mans Master
Thread Starter
The Eco car!
"When first announced, McLaren claimed that it would have a higher horsepower to carbon dioxide emission ratio than any internal-combustion engine available at the time."
That's what I really want, a supercar that farts lightly. Oh, and can go over a speed bump without messing my hairdo. If only there was a competitor to show how a supercar should feel and sound... hint 458.
12-09-2012, 08:18 PM
#28
Team Owner
So do PD superchargers. My factory PD supercharged Mercedes sedan gets 19 around town and 29 on the highway at 75 MPH(and it's 14 year old technology). I consider that pretty darn good.
12-09-2012, 08:18 PM
#29
Safety Car
Turbos can be mounted in the valley, have been mounted in the valley, and if GM were to use them there is a good chance they will end up in the valley. See BMW:
12-09-2012, 08:19 PM
#30
Le Mans Master
Thread Starter
Sensible People!
Turbos. They don't have nearly the same paralytic drag, so they produce the more horsepowe at the same boost.
They do not "produce" heat. All of the heat of an engine is produced via combustion. Turbos will absorb heat and radiate it to some degree wherever they are located. Proper design and shielding will reduce this issue. They will heat the intake charge due to compression, but do so all forced induction conpressors, no matter how they are driven.
The only type of racing where turbos have not dominated roots or other engine driven compressors is drag racing.
Do they require a different style of driving? Yes, but any competent driver should be able to master it, if properly trained or they have a desire to learn.
Today's DCTs reduce one of the turbo's issues, coming off boost when lifting the throttle for shifting. No lift, no reduced boost.
Turbo's are a bit easier to intercool.
They do not "produce" heat. All of the heat of an engine is produced via combustion. Turbos will absorb heat and radiate it to some degree wherever they are located. Proper design and shielding will reduce this issue. They will heat the intake charge due to compression, but do so all forced induction conpressors, no matter how they are driven.
The only type of racing where turbos have not dominated roots or other engine driven compressors is drag racing.
Do they require a different style of driving? Yes, but any competent driver should be able to master it, if properly trained or they have a desire to learn.
Today's DCTs reduce one of the turbo's issues, coming off boost when lifting the throttle for shifting. No lift, no reduced boost.
Turbo's are a bit easier to intercool.
12-09-2012, 08:23 PM
#31
Le Mans Master
Thread Starter
Outstanding!
In the comparisons the tach hardly ever comes down low enough for mid and low sections of the powerband to matter
Turbos can be mounted in the valley, have been mounted in the valley, and if GM were to use them there is a good chance they will end up in the valley. See BMW:
Turbos can be mounted in the valley, have been mounted in the valley, and if GM were to use them there is a good chance they will end up in the valley. See BMW:
Last edited by johnglenntwo; 12-09-2012 at 08:26 PM.
12-09-2012, 08:36 PM
#33
Safety Car
That BMW DOHC head is taller than the small block, and yet those turbines are towering over. It will need at least as much hood clearance as the TVS. Then think that 750hp will require much larger turbines. It will be a really tall block.
I would say circuit racing is dominated by all motor applications. If Turbos were so great, there would be virtually no Porsche GT3s sold, only 911 Turbos, and GT2s. I can tell you for a fact there are loads of GT3s on the Nurburgring, probably the most common car there when they rent out the track for Porsche events.
I would say circuit racing is dominated by all motor applications. If Turbos were so great, there would be virtually no Porsche GT3s sold, only 911 Turbos, and GT2s. I can tell you for a fact there are loads of GT3s on the Nurburgring, probably the most common car there when they rent out the track for Porsche events.
12-09-2012, 08:45 PM
#34
Team Owner
That BMW DOHC head is taller than the small block, and yet those turbines are towering over. It will need at least as much hood clearance as the TVS. Then think that 750hp will require much larger turbines. It will be a really tall block.
I would say circuit racing is dominated by all motor applications. If Turbos were so great, there would be virtually no Porsche GT3s sold, only 911 Turbos, and GT2s. I can tell you for a fact there are loads of GT3s on the Nurburgring, probably the most common car there when they rent out the track for Porsche events.
I would say circuit racing is dominated by all motor applications. If Turbos were so great, there would be virtually no Porsche GT3s sold, only 911 Turbos, and GT2s. I can tell you for a fact there are loads of GT3s on the Nurburgring, probably the most common car there when they rent out the track for Porsche events.
12-09-2012, 08:53 PM
#35
Le Mans Master
Thread Starter
Scary torque!
That BMW DOHC head is taller than the small block, and yet those turbines are towering over. It will need at least as much hood clearance as the TVS. Then think that 750hp will require much larger turbines. It will be a really tall block.
I would say circuit racing is dominated by all motor applications. If Turbos were so great, there would be virtually no Porsche GT3s sold, only 911 Turbos, and GT2s. I can tell you for a fact there are loads of GT3s on the Nurburgring, probably the most common car there when they rent out the track for Porsche events.
I would say circuit racing is dominated by all motor applications. If Turbos were so great, there would be virtually no Porsche GT3s sold, only 911 Turbos, and GT2s. I can tell you for a fact there are loads of GT3s on the Nurburgring, probably the most common car there when they rent out the track for Porsche events.
And we've talked about packaging before and here you are talking about the rudest car ever to hit the planet now becoming optimum.
12-09-2012, 08:54 PM
#36
Safety Car
All this is moot imo, Keeks showed us the LT4, it will be roots. That turbo engine on the dyno was barely visible, it could be the V6 going into the ATS to satisfy the Euro market. It could also be a test mule that never sees production. The rendering Keeks showed us looked factory fresh and ready to roll out to costumers.
12-09-2012, 08:55 PM
#37
Team Owner
The SLS AMG St gets a NA 6.3L V8 with 583HP but drops to 13 in town and 19 highway.
A 450 HP base C7 that gets around 22 in town and 30 on the highway for a measly $50,000 looks pretty darn good. I bet a factory PD supercharged C7 with around 550-575 HP for $65,000/$70,000 and getting 20 in town and 27 on the highway would really be neat.
12-09-2012, 09:02 PM
#39
Team Owner
12-09-2012, 09:04 PM
#40
Safety Car
I can live with 475hp car daily, and 575hp at the track. Any 335 section street tire will be the limitation at that point and I'm not ever planning on running slicks or special order Veyron Michelins.