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Some of you might know that I've been talking of going the twin turbo route. The current 285kW (380Hp) at the wheels on 95 unleaded (untuned) is nice but the lag is terrible. So after much deliberation bewtween Martin and I, he finally convinced me to go twincharged, i.e Supercharger for the bottom end and turbo up top.
I tracked down a mercedes C32 AMG charger and fitted that to my motor. Below is a pic.
What you don't see on the pic is the mods that were required to get it to fit.
1. Redesigned and manufatured engine mounting
2. relocated power steering pipes
3. relocated powersteering reservoir
4. relocated water pipes
5. relocated engine harnass
6. relocated breathing system
7. modified block
8. modified sump
9. relocated window washer bottle
10. modified rib belt tensioner to cope with the added stresses
I managed (just) to keep the fan standard.
On the control side of things (not shown), the setup now has 2 separate air filters. One for the charger, and one for the turbo. Here it gets tricky (read: friggen messy) to sort out the switchover bewteen charger and turbo. It basically consistes of an extra N75 controlling one boost actuator to operate the bypass valve (a 72mm throttle body) when the switch happens. Getting it smooth is another issue. There is also a custom vacuum actuator that controls the waste function of the charger for cruising and idling bypass conditions. The boostpipes required for all this gets interesting at the connection point due to major space constraints.
Here is my boost curve as now. Note that the turbo comes on line at 5000rpm. That is only part of the story. With the increased exhaust flow the turbo now spools at 3300rpm instead of 4700rpm. The problem is the compressor map of the turbo. Trying to boost moere than 1.6bar before 5000rpm leads to major compressor surge, which will destroy the turbo. It does however mean that I can now go to a .91 AR instead of the current small .64AR as lafg is not an issue anymore.....
The boost responce on the car is now unreal. In any gear at ANY revs there is immediate torque, and plenty, and I havent even set the pulley ratios on the charger to max yet. There is about another 26% in there......
I'l post dyno curves as soon as I've done one.
I tracked down a mercedes C32 AMG charger and fitted that to my motor. Below is a pic.
What you don't see on the pic is the mods that were required to get it to fit.
1. Redesigned and manufatured engine mounting
2. relocated power steering pipes
3. relocated powersteering reservoir
4. relocated water pipes
5. relocated engine harnass
6. relocated breathing system
7. modified block
8. modified sump
9. relocated window washer bottle
10. modified rib belt tensioner to cope with the added stresses
I managed (just) to keep the fan standard.
On the control side of things (not shown), the setup now has 2 separate air filters. One for the charger, and one for the turbo. Here it gets tricky (read: friggen messy) to sort out the switchover bewteen charger and turbo. It basically consistes of an extra N75 controlling one boost actuator to operate the bypass valve (a 72mm throttle body) when the switch happens. Getting it smooth is another issue. There is also a custom vacuum actuator that controls the waste function of the charger for cruising and idling bypass conditions. The boostpipes required for all this gets interesting at the connection point due to major space constraints.
Here is my boost curve as now. Note that the turbo comes on line at 5000rpm. That is only part of the story. With the increased exhaust flow the turbo now spools at 3300rpm instead of 4700rpm. The problem is the compressor map of the turbo. Trying to boost moere than 1.6bar before 5000rpm leads to major compressor surge, which will destroy the turbo. It does however mean that I can now go to a .91 AR instead of the current small .64AR as lafg is not an issue anymore.....
The boost responce on the car is now unreal. In any gear at ANY revs there is immediate torque, and plenty, and I havent even set the pulley ratios on the charger to max yet. There is about another 26% in there......
I'l post dyno curves as soon as I've done one.
More pics please!
)
More likely the enormity of trying to make it transition smoothly was all too real.
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