Quad Turbos
05-31-2003, 06:17 PM
#1
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Quad Turbos
Larger turbos take longer to spool up but make high end hp, great for racing where your RPM's are always high anyway.
Smaller turbos spool up quicker for less lag, but max out quicker than the large ones.
I'm not all that mechanically inclined, so maybe i'm missing the obvious,,,,,BUT,,,,
Has anyone ever devised a system using 4 smaller turbos, one dedicated to each cylinder? Would that be the best of both worlds?
Smaller turbos spool up quicker for less lag, but max out quicker than the large ones.
I'm not all that mechanically inclined, so maybe i'm missing the obvious,,,,,BUT,,,,
Has anyone ever devised a system using 4 smaller turbos, one dedicated to each cylinder? Would that be the best of both worlds?
05-31-2003, 07:08 PM
#2
Burning Brakes
something like when the first reaches it's limit it then boosts the car at the same tome still creat preassure to spool another and so forth?the idea is there but where to put four turbos? the 951 already has a tight pack.
05-31-2003, 07:16 PM
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There is a thread about this over on <a href="http://www.dsmtalk.com" target="_blank">www.dsmtalk.com</a>
This is pure theory, since it would be terribly impracticle. The way they dreamed it up over there was each cylinder running independently off of one of four extremely small simultaneous turbos. A single exhaust runner feeds one turbo, which compresses air directly back into the head, with individual throttle bodies in each intake runner. This obviously prevents intercooling, so water injection would be necessary. Pretty wild, but the limiting factor would be finding a place for 4 turbochargers under an already cramped hood.
This is pure theory, since it would be terribly impracticle. The way they dreamed it up over there was each cylinder running independently off of one of four extremely small simultaneous turbos. A single exhaust runner feeds one turbo, which compresses air directly back into the head, with individual throttle bodies in each intake runner. This obviously prevents intercooling, so water injection would be necessary. Pretty wild, but the limiting factor would be finding a place for 4 turbochargers under an already cramped hood.
05-31-2003, 08:14 PM
#5
Race Director
"Smaller turbos spool up quicker for less lag, but max out quicker than the large ones."
No... smaller turbos spool up quicker given the same exhaust-pressure to generate a lower boost-level. If you split your exhaust power into quarters, you'll only have 1/4 the energy to drive each turbo. Four smaller turbos that deliver 1/4 the flow of a larger turbo would actually have way more than 1/4 the inertial mass to drive. If you split your exhaust gases and its driving power into quarters, driving those four smaller turbos in parallel would result in more lag and less boost. The only reason parallel twin turbos are currently used is for simplicity in design and packaging in V and flat engines.
When you make the effort, twin sequential turbos are the way to go. In this arrangement, all of the exhaust gases are forced into one small turbo at low-RPM to generate the fastest boost possible. As this turbo runs out of steam at say... 3500rpm, the exhaust is split and diverted to the second turbo and they both will then max out at 7000rpm.
Take for example the twin sequential turbo set-up in the SupraTT. At low-RPM, low-load, ALL six cylinder's exhaust is driving a small turbo the size of a KKK-K24 turbo. Imagine the small lag you would get with a 3.0L engine driving that tiny turbo. But it's only good up to about 3500-4000rpm. At 3000rpm, the second turbo is pre-spooled by the exhaust slowing diverting into the second turbo. By 4000rpm, both are running full steam. When this is occuring, it's 6-cylinders driving two turbos, NOT two turbos being driven by 3-cylinders apiece. Max-boost on the Supra comes on at 2200rpm or so and it can hold it all the way to redline. The torque curve is quite flat.
No... smaller turbos spool up quicker given the same exhaust-pressure to generate a lower boost-level. If you split your exhaust power into quarters, you'll only have 1/4 the energy to drive each turbo. Four smaller turbos that deliver 1/4 the flow of a larger turbo would actually have way more than 1/4 the inertial mass to drive. If you split your exhaust gases and its driving power into quarters, driving those four smaller turbos in parallel would result in more lag and less boost. The only reason parallel twin turbos are currently used is for simplicity in design and packaging in V and flat engines.
When you make the effort, twin sequential turbos are the way to go. In this arrangement, all of the exhaust gases are forced into one small turbo at low-RPM to generate the fastest boost possible. As this turbo runs out of steam at say... 3500rpm, the exhaust is split and diverted to the second turbo and they both will then max out at 7000rpm.
Take for example the twin sequential turbo set-up in the SupraTT. At low-RPM, low-load, ALL six cylinder's exhaust is driving a small turbo the size of a KKK-K24 turbo. Imagine the small lag you would get with a 3.0L engine driving that tiny turbo. But it's only good up to about 3500-4000rpm. At 3000rpm, the second turbo is pre-spooled by the exhaust slowing diverting into the second turbo. By 4000rpm, both are running full steam. When this is occuring, it's 6-cylinders driving two turbos, NOT two turbos being driven by 3-cylinders apiece. Max-boost on the Supra comes on at 2200rpm or so and it can hold it all the way to redline. The torque curve is quite flat.
06-01-2003, 12:19 AM
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The Supras twin-sequential system is very cool but it sucks to work on! It is easier to pull the motor and pull of the turbo assemblies then to just try and pull off the turbo assemblies with the engine still in the car.
Here is a pciture of a parralel turbo set-up I built for a Supra.
<a href="http://boards.rennlist.com/upload/supraheader0005.JPG" target="_blank">http://boards.rennlist.com/upload/supraheader0005.JPG</a>
You can see that the first three runners feed one turbo and the last three runners feed another turbo. Ofcourse these headers are feeding two gigantic t-66 turbos:^)
<a href="http://www.speedforceracing.com/Supra/supraturbos001.jpg" target="_blank">http://www.speedforceracing.com/Supra/supraturbos001.jpg</a>
The Bugatti EB110 has quad turbos as well as the Ford GT90.
Here is a pciture of a parralel turbo set-up I built for a Supra.
<a href="http://boards.rennlist.com/upload/supraheader0005.JPG" target="_blank">http://boards.rennlist.com/upload/supraheader0005.JPG</a>
You can see that the first three runners feed one turbo and the last three runners feed another turbo. Ofcourse these headers are feeding two gigantic t-66 turbos:^)
<a href="http://www.speedforceracing.com/Supra/supraturbos001.jpg" target="_blank">http://www.speedforceracing.com/Supra/supraturbos001.jpg</a>
The Bugatti EB110 has quad turbos as well as the Ford GT90.