Evo Mag: Parr Cayman Turbo
Discussion
Re: how can it make that much power from such low boost, the answer is in the torque curve. I don't have Evo in front of me but iirc the engine develops approx max 360 lb/ft torque. Formula for bhp = torque in lb/ft * rpm / 5252, so: if the engine is making 360 lb/ft @ 7000 rpm then that is 480bhp. Evo state the car retains it's power delivery - which builds in a fairly linear manner as the rpm rises, so I assume it makes a reasonable amount of torque high up in the rev range, hence why there is what first looks like an out of proportion bhp increase compared to the torque increase. It's all in the rpm!
P.s. An engine that makes 200 lb/ft at 2000rpm is only making 76 bhp, with 200lb/ft at 10000rpm it's making 380bhp! Think of the rpm as the amount of times the torque figure is being delivered to the wheels, or something along those lines. Which is why bike/F1 engines make massive power from so little torque, because it's at such a high rpm.
P.s. An engine that makes 200 lb/ft at 2000rpm is only making 76 bhp, with 200lb/ft at 10000rpm it's making 380bhp! Think of the rpm as the amount of times the torque figure is being delivered to the wheels, or something along those lines. Which is why bike/F1 engines make massive power from so little torque, because it's at such a high rpm.
S1MMA said:
Re: how can it make that much power from such low boost, the answer is in the torque curve. I don't have Evo in front of me but iirc the engine develops approx max 360 lb/ft torque. Formula for bhp = torque in lb/ft * rpm / 5252, so: if the engine is making 360 lb/ft @ 7000 rpm then that is 480bhp. Evo state the car retains it's power delivery - which builds in a fairly linear manner as the rpm rises, so I assume it makes a reasonable amount of torque high up in the rev range, hence why there is what first looks like an out of proportion bhp increase compared to the torque increase. It's all in the rpm!
P.s. An engine that makes 200 lb/ft at 2000rpm is only making 76 bhp, with 200lb/ft at 10000rpm it's making 380bhp! Think of the rpm as the amount of times the torque figure is being delivered to the wheels, or something along those lines. Which is why bike/F1 engines make massive power from so little torque, because it's at such a high rpm.
Yes, I understand all that... But that includes assumptions about what torque it makes... The simple boost calc is just as reasonable and says the figure should be lower and perhaps falls more in line with Casey's whp figures on the page before...P.s. An engine that makes 200 lb/ft at 2000rpm is only making 76 bhp, with 200lb/ft at 10000rpm it's making 380bhp! Think of the rpm as the amount of times the torque figure is being delivered to the wheels, or something along those lines. Which is why bike/F1 engines make massive power from so little torque, because it's at such a high rpm.
dom9 said:
S1MMA said:
Re: how can it make that much power from such low boost, the answer is in the torque curve. I don't have Evo in front of me but iirc the engine develops approx max 360 lb/ft torque. Formula for bhp = torque in lb/ft * rpm / 5252, so: if the engine is making 360 lb/ft @ 7000 rpm then that is 480bhp. Evo state the car retains it's power delivery - which builds in a fairly linear manner as the rpm rises, so I assume it makes a reasonable amount of torque high up in the rev range, hence why there is what first looks like an out of proportion bhp increase compared to the torque increase. It's all in the rpm!
P.s. An engine that makes 200 lb/ft at 2000rpm is only making 76 bhp, with 200lb/ft at 10000rpm it's making 380bhp! Think of the rpm as the amount of times the torque figure is being delivered to the wheels, or something along those lines. Which is why bike/F1 engines make massive power from so little torque, because it's at such a high rpm.
Yes, I understand all that... But that includes assumptions about what torque it makes... The simple boost calc is just as reasonable and says the figure should be lower and perhaps falls more in line with Casey's whp figures on the page before...P.s. An engine that makes 200 lb/ft at 2000rpm is only making 76 bhp, with 200lb/ft at 10000rpm it's making 380bhp! Think of the rpm as the amount of times the torque figure is being delivered to the wheels, or something along those lines. Which is why bike/F1 engines make massive power from so little torque, because it's at such a high rpm.
Power = 2 x PI x N (rpm) x T (torque)
From the graphs I can find on the net, the standard Cayman S engine makes a flat 320hp from 6000rpm to 7000rpm, which means that the torque curve is falling from 6000rpm onwards as a result of a reducing volumetric efficiency. If you could re-tune the standard engine to produce the same torque at 7000 that it makes at 6000, by manipulating the above equation you would have:
320hp x 7000/6000 = 373hp
As stated above, at 5pi of boost, assuming that you maintain a constant intake temperature you will get approximately (14.5 + 5)psi/14.5psi = 1.34 (134%) increase in the mass of the air going through the engine.
Assuming that the turbochargers are not flat out, it is reasonable to assume that they can maintain this boost pressure up to 7000rpm and let's also allow for an addditional 5% loss in mechanical efficiency due to the extra cylinder pressure & associated heat problems. The resulting power would be:
373hp x 1.34 x 0.95 = 475hp
The claim of 480hp seems reasonable to me provided the engine is intercooled efficiently, which is a big if. For instance, if the air temperature increased from 15C to 40C, the density reduction is 8%, in which case the power would reduce accordingly:
475hp x 0.92 = 437hp
From the graphs I can find on the net, the standard Cayman S engine makes a flat 320hp from 6000rpm to 7000rpm, which means that the torque curve is falling from 6000rpm onwards as a result of a reducing volumetric efficiency. If you could re-tune the standard engine to produce the same torque at 7000 that it makes at 6000, by manipulating the above equation you would have:
320hp x 7000/6000 = 373hp
As stated above, at 5pi of boost, assuming that you maintain a constant intake temperature you will get approximately (14.5 + 5)psi/14.5psi = 1.34 (134%) increase in the mass of the air going through the engine.
Assuming that the turbochargers are not flat out, it is reasonable to assume that they can maintain this boost pressure up to 7000rpm and let's also allow for an addditional 5% loss in mechanical efficiency due to the extra cylinder pressure & associated heat problems. The resulting power would be:
373hp x 1.34 x 0.95 = 475hp
The claim of 480hp seems reasonable to me provided the engine is intercooled efficiently, which is a big if. For instance, if the air temperature increased from 15C to 40C, the density reduction is 8%, in which case the power would reduce accordingly:
475hp x 0.92 = 437hp
Charge cooling is a reasonable solution, however at some point the system will heat soak, the intake temperature rises and the engine loses power, that's not to say this is a big issue as even factory intercoolers do this on their turbocharged versions. For road use it's probably not an issue, but the big question would be how long does heat soak takes when flat out, on track on a hot summer's day?
In terms of power loss, with a 40C air temp increase you are down 15% and with an 80C increase you are down by 22%, which is a cool 105hp!
In terms of power loss, with a 40C air temp increase you are down 15% and with an 80C increase you are down by 22%, which is a cool 105hp!
NineMeister said:
Charge cooling is a reasonable solution, however at some point the system will heat soak, the intake temperature rises and the engine loses power, that's not to say this is a big issue as even factory intercoolers do this on their turbocharged versions. For road use it's probably not an issue, but the big question would be how long does heat soak takes when flat out, on track on a hot summer's day?
In terms of power loss, with a 40C air temp increase you are down 15% and with an 80C increase you are down by 22%, which is a cool 105hp!
Blinkin ek, you boys know your stuff..In terms of power loss, with a 40C air temp increase you are down 15% and with an 80C increase you are down by 22%, which is a cool 105hp!
NineMeister said:
Power = 2 x PI x N (rpm) x T (torque)
From the graphs I can find on the net, the standard Cayman S engine makes a flat 320hp from 6000rpm to 7000rpm, which means that the torque curve is falling from 6000rpm onwards as a result of a reducing volumetric efficiency. If you could re-tune the standard engine to produce the same torque at 7000 that it makes at 6000, by manipulating the above equation you would have:
320hp x 7000/6000 = 373hp
As stated above, at 5pi of boost, assuming that you maintain a constant intake temperature you will get approximately (14.5 + 5)psi/14.5psi = 1.34 (134%) increase in the mass of the air going through the engine.
Assuming that the turbochargers are not flat out, it is reasonable to assume that they can maintain this boost pressure up to 7000rpm and let's also allow for an addditional 5% loss in mechanical efficiency due to the extra cylinder pressure & associated heat problems. The resulting power would be:
373hp x 1.34 x 0.95 = 475hp
The claim of 480hp seems reasonable to me provided the engine is intercooled efficiently, which is a big if. For instance, if the air temperature increased from 15C to 40C, the density reduction is 8%, in which case the power would reduce accordingly:
475hp x 0.92 = 437hp
Again, with a big assumption about torque...From the graphs I can find on the net, the standard Cayman S engine makes a flat 320hp from 6000rpm to 7000rpm, which means that the torque curve is falling from 6000rpm onwards as a result of a reducing volumetric efficiency. If you could re-tune the standard engine to produce the same torque at 7000 that it makes at 6000, by manipulating the above equation you would have:
320hp x 7000/6000 = 373hp
As stated above, at 5pi of boost, assuming that you maintain a constant intake temperature you will get approximately (14.5 + 5)psi/14.5psi = 1.34 (134%) increase in the mass of the air going through the engine.
Assuming that the turbochargers are not flat out, it is reasonable to assume that they can maintain this boost pressure up to 7000rpm and let's also allow for an addditional 5% loss in mechanical efficiency due to the extra cylinder pressure & associated heat problems. The resulting power would be:
373hp x 1.34 x 0.95 = 475hp
The claim of 480hp seems reasonable to me provided the engine is intercooled efficiently, which is a big if. For instance, if the air temperature increased from 15C to 40C, the density reduction is 8%, in which case the power would reduce accordingly:
475hp x 0.92 = 437hp
I am interested in this, hence why I would be interested in seeing numbers from a respected UK rolling road. It looks a very good price, especially what Casey has quoted in USD and is certainly more cost effective £/bhp than pretty much anything else I have seen but I am struggling to see it make this power with that turbo on the base engine. The VE will change when you swap the NA exhaust setup for the turbos and so I don't think you can directly correlate the NA bhp figures with the turbo. As a rule of thumb, sure, but I thought I was generous doing 340bhp x 1.35 keeping the NA inlet temperature constant, which I doubt it will be.
I am just interested that is all... I am just trying to reconcile how much power this is might put through an arguably weak M96/97 block to think about durability etc etc
The article states that the kits have amassed 30k miles overseas. That isnt even close. We have one client with over 40k miles on the system now. I would say over the world we have ~250k on all of the systems... Heck, we had 20k on our shop car and half of that was dyno/track miles. I can provide any dyno charts needed if anyone wants them. we have independent dynos as well. We have a car in the shop getting race headers(catless) and a boost controller. At 6psi on 93 octane the car is going to make ~455-460whp.
Casey
Casey
Sorry Casey, what is the make and model of the turbo you guys use? Is it a single turbo or twin turbos, sorry if I have missed this, but I am not sure it has been explicitly pointed out.
If it is a single turbo, that is some serious power, no one has mentioned lag though, so I assume it has a quick spool?
You say you are doing race headers without the cats, where are the cats in the current system? Ahead or behind the turbo? I assumed you would have had custom headers with teh turbos on the end and then a cat downstream if/ where necessary.
If it is a single turbo, that is some serious power, no one has mentioned lag though, so I assume it has a quick spool?
You say you are doing race headers without the cats, where are the cats in the current system? Ahead or behind the turbo? I assumed you would have had custom headers with teh turbos on the end and then a cat downstream if/ where necessary.
dom9 said:
NineMeister said:
Power = 2 x PI x N (rpm) x T (torque)
From the graphs I can find on the net, the standard Cayman S engine makes a flat 320hp from 6000rpm to 7000rpm, which means that the torque curve is falling from 6000rpm onwards as a result of a reducing volumetric efficiency. If you could re-tune the standard engine to produce the same torque at 7000 that it makes at 6000, by manipulating the above equation you would have:
320hp x 7000/6000 = 373hp
As stated above, at 5pi of boost, assuming that you maintain a constant intake temperature you will get approximately (14.5 + 5)psi/14.5psi = 1.34 (134%) increase in the mass of the air going through the engine.
Assuming that the turbochargers are not flat out, it is reasonable to assume that they can maintain this boost pressure up to 7000rpm and let's also allow for an addditional 5% loss in mechanical efficiency due to the extra cylinder pressure & associated heat problems. The resulting power would be:
373hp x 1.34 x 0.95 = 475hp
The claim of 480hp seems reasonable to me provided the engine is intercooled efficiently, which is a big if. For instance, if the air temperature increased from 15C to 40C, the density reduction is 8%, in which case the power would reduce accordingly:
475hp x 0.92 = 437hp
Again, with a big assumption about torque...From the graphs I can find on the net, the standard Cayman S engine makes a flat 320hp from 6000rpm to 7000rpm, which means that the torque curve is falling from 6000rpm onwards as a result of a reducing volumetric efficiency. If you could re-tune the standard engine to produce the same torque at 7000 that it makes at 6000, by manipulating the above equation you would have:
320hp x 7000/6000 = 373hp
As stated above, at 5pi of boost, assuming that you maintain a constant intake temperature you will get approximately (14.5 + 5)psi/14.5psi = 1.34 (134%) increase in the mass of the air going through the engine.
Assuming that the turbochargers are not flat out, it is reasonable to assume that they can maintain this boost pressure up to 7000rpm and let's also allow for an addditional 5% loss in mechanical efficiency due to the extra cylinder pressure & associated heat problems. The resulting power would be:
373hp x 1.34 x 0.95 = 475hp
The claim of 480hp seems reasonable to me provided the engine is intercooled efficiently, which is a big if. For instance, if the air temperature increased from 15C to 40C, the density reduction is 8%, in which case the power would reduce accordingly:
475hp x 0.92 = 437hp
I am interested in this, hence why I would be interested in seeing numbers from a respected UK rolling road. It looks a very good price, especially what Casey has quoted in USD and is certainly more cost effective £/bhp than pretty much anything else I have seen but I am struggling to see it make this power with that turbo on the base engine. The VE will change when you swap the NA exhaust setup for the turbos and so I don't think you can directly correlate the NA bhp figures with the turbo. As a rule of thumb, sure, but I thought I was generous doing 340bhp x 1.35 keeping the NA inlet temperature constant, which I doubt it will be.
I am just interested that is all... I am just trying to reconcile how much power this is might put through an arguably weak M96/97 block to think about durability etc etc
Dom. It is a proprietary single turbo close to the size of a T4 that we build to spec for the application. The "t" in TPC stands for Turbo. We have been doing it for a while. The turbo is after the exhaust Manifold. 99% of cars with the system use stock cats but recently we have been exploring to make more power at the same boost. Shoot me an email if you have further questions.
The system is virtually lag free. very linear.
The system is virtually lag free. very linear.
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