Return of varioram?
02-25-2018, 02:18 PM
#1
Three Wheelin'
Thread Starter
Return of varioram?
I just read that the 991.2 gt3 has a new variable induction system to boost low rev torque. Sound familiar? Anyone know how similar this is to the 993 VR system?
Intake system.
Intake system.
Like the racing engines for the 911 GT3 R, 911 Cup and 911 RS models,the 911 GT3 motor is a naturally aspirated engine uncompromisingly designed for high engine speeds. In the newly designed variable intake system,made of lightweight plastic,there are now 2 resonance butterflies. The previous model had only one. Depending on the load demand and engine speed,they open either individually or simultaneously,providing a higher torque curve than before. One positive side effect of the technology is the efficient gas cycle,which is advantageous in terms of fuel consumption.
02-26-2018, 09:53 AM
#3
RL Community Team
Rennlist Member
Rennlist Member
Hi Steve,
I assume one, on the G2, simply opens a flap to change the volume of the intake system so pressure waves from intake create a positive pressure pulse during cylinder charging.
and the other, On a VArioram 993, changes the length of the intake runner to synchronize the pulse to create the positive pressure during charging.
If I am correct is it six of one half a dozen of the other or is one more effective than the other?
Andy
02-26-2018, 10:43 AM
#4
Three Wheelin'
Thread Starter
Would love to hear the answer to this question and also why VR hasn’t come back in any models after the 993 (that I know of).
The GT3 also has a ram air intake (good for 20hp they say at high speeds) so that would surely play into the design of the induction system as well.
The GT3 also has a ram air intake (good for 20hp they say at high speeds) so that would surely play into the design of the induction system as well.
02-26-2018, 12:22 PM
#5
Would love to hear the answer to this question and also why VR hasn’t come back in any models after the 993 (that I know of).
The GT3 also has a ram air intake (good for 20hp they say at high speeds) so that would surely play into the design of the induction system as well.
The GT3 also has a ram air intake (good for 20hp they say at high speeds) so that would surely play into the design of the induction system as well.
On a 993 vram there are 3 intake regimes, controlled by the resonance flap and runner length
A) long tubes & resonance flap closed
B) short tubes & resonance flap closed
C) short tubes & resonance flap open
the GT3 regimes haven't been clearly articulated(that I have seen) but the 2 resonance flaps have a max of different 4 different cross section and volume, so upto 4 possible resonance states
02-26-2018, 12:32 PM
#6
Rennlist Member
Last edited by MarinS4; 02-28-2018 at 11:47 AM.
02-26-2018, 01:48 PM
#7
Three Wheelin'
Thread Starter
That makes sense except that they are still doing variable intake resonance with the gt3. Perhaps the complexity of variable length runners is not worthwhile since you can get a similar effect with flaps alone?
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03-02-2018, 10:30 AM
#8
This piqued my interest so I did a little more research
All the GT3Cups since 997 versions use a 4 stage resonance intake w/ 2x resonance flaps,
RSR doesn't use this they instead use ITBs
It's interesting that Jeff Gamroth seems to use the 997Gt3 Cup dual resonance flap manifolds w/ ITB's on his magnificent engines
All the GT3Cups since 997 versions use a 4 stage resonance intake w/ 2x resonance flaps,
RSR doesn't use this they instead use ITBs
It's interesting that Jeff Gamroth seems to use the 997Gt3 Cup dual resonance flap manifolds w/ ITB's on his magnificent engines
03-02-2018, 11:59 AM
#9
Rennlist Member
On another note of cool upcoming technology. Electric hybrid turbos are going to be a game changer. Imagine the end of turbo lag? One of the designs I’ve seen uses electric motor to spool turbo at low RPM and let’s exhaust gases drive it on the top end. This technology will allow for over 100% cylinder fill at all RPM’s.
03-02-2018, 12:16 PM
#10
Rennlist Member
It really comes down to % of cylinder fill at xxxx rpm. It sure seems like VVT with resonance chambers allow for a high enough percentage of cylinder fill it’s not worth chasing what’s left on the table.
On another note of cool upcoming technology. Electric hybrid turbos are going to be a game changer. Imagine the end of turbo lag? One of the designs I’ve seen uses electric motor to spool turbo at low RPM and let’s exhaust gases drive it on the top end. This technology will allow for over 100% cylinder fill at all RPM’s.
03-03-2018, 02:02 AM
#11
RL Technical Advisor
03-03-2018, 03:19 AM
#12
Rennlist Member
https://jalopnik.com/this-is-the-dif...ger-1795017793
Last edited by samurai_k; 03-03-2018 at 01:55 PM.
03-03-2018, 10:32 AM
#13
Technical Guru
Rennlist Member
Rennlist Member
Borg Warner has had these electric turbochargers sitting on a shelf for almost 20 years... Up until now car manufacturers have not been willing to increases their vehicle costs to support the voltages required (48V) just for this single function.
03-06-2018, 03:34 PM
#14
RL Community Team
Rennlist Member
Rennlist Member
Cars will get at least a 30% to 50% reduction in fuel economy, but who cares and Monsanto continues making Billions selling corn seed to farmers so they can continue to grow outsized corn crops at a profit! Seems to me using fertilizer made from natural gas to grow corn to convert it into fuel while spot food shortages exist throughout the world is wee bit wasteful and ethically challenged.
Andy