Custom Twin turbo engine
dyno
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Specifications of customization
Thanks again for you interest in the engine.
For starters I purchased an ALMS GT3 RS race motor from Alex Job Racing. The reasons for doing that is I wanted to have the six butterfly intake set up those engines ran, also they use solid followers for the cams and not hydraulic lifters which will limit the camshaft that you can run based on the opening and closing ramps for one thing. We wanted to use a proper race cam for turbo application. At the time there was nothing available. Now we have a good starting point. We took engine completely apart and evaluated the components in it. We determined not to use the Ti rods because of the loads that the boost would add we did not expect them to last for very long.
The crank is a great piece but we still do a lot of work to it to improve the oiling to the bearings. You think well why bother since the engine spins to 9000 already. That is correct but when you consider how Porsche did it you need to take a step back and think. What they did was to lower the reciprocating weight on the crank lowering the loads on the rod bearings allowing them to run higher revs without rods stretching and pinching the bearings. Me, on the other hand increased the weight because we ran a steel rod and a bit heavier piston. So we modify the rod journals to run a proper racing bearing that will give us more eccentricity at light loads and be the right size at high revs. We also supply oil to all rod journals from every main bearing. The rods are a different length that stock so we can install a piston with a thicker dome. Do not want it to melt through the middle. The cylinder heads where not used since the ports are huge. We focused on velocity so we went with a smaller head and worked it to get us the desired port volume and matched them to the intake.
Once that was done we started the design of the intake system which
used velocity stacks going into a common plenum made of carbon fiber. We also determined that the fuel required a big injector so instead of using just one we installed 2 injectors per cylinder which measured 110 lbs/hr.
After that was done we put the whole assembly on a flow bench to measure what we had and to make any improvements that we could. After gathering the data we used it to have a Custom camshaft made for our engine. Having this data is critical for proper cam design as you want to know what the valve sees with the whole system together, intake and exhaust. That way you can get the most out of your package, otherwise it will not be optimized for what you have done. The followers where all coated DLC to improve on longevity and to minize friction as well. The rings on the pistons are NPR rings and the material for the top ring is tool steel.
The cylinders are Mahle race cylinders. Tried iron sleeves as well. Work good but Mahle is easier to get.
The exhaust was completely hand made for the application since it is not something you can buy off the shelf. The primaries are 2" and end in a 3 into 1 merge collector from Burns stainless. The wastegates are 2 44mm Tials and the turbos are Garrett twin ball bearings. There are two intercoolers since the car design will allow for better flow that way. These were fabricated and spec for the engine. There where so many parts that had to be made to do the whole job, countless ours. We even incorporated a DBW to do the throttle actuation. After proving a bit slow in response we removed it for a cable style. The engine has a sequential trans attached to it with a custom Paddle Shift kit that we design and built. Hope this is a good description of what we did. We still have parts to build a couple more, any takers.
Respectfully
Ivan
For starters I purchased an ALMS GT3 RS race motor from Alex Job Racing. The reasons for doing that is I wanted to have the six butterfly intake set up those engines ran, also they use solid followers for the cams and not hydraulic lifters which will limit the camshaft that you can run based on the opening and closing ramps for one thing. We wanted to use a proper race cam for turbo application. At the time there was nothing available. Now we have a good starting point. We took engine completely apart and evaluated the components in it. We determined not to use the Ti rods because of the loads that the boost would add we did not expect them to last for very long.
The crank is a great piece but we still do a lot of work to it to improve the oiling to the bearings. You think well why bother since the engine spins to 9000 already. That is correct but when you consider how Porsche did it you need to take a step back and think. What they did was to lower the reciprocating weight on the crank lowering the loads on the rod bearings allowing them to run higher revs without rods stretching and pinching the bearings. Me, on the other hand increased the weight because we ran a steel rod and a bit heavier piston. So we modify the rod journals to run a proper racing bearing that will give us more eccentricity at light loads and be the right size at high revs. We also supply oil to all rod journals from every main bearing. The rods are a different length that stock so we can install a piston with a thicker dome. Do not want it to melt through the middle. The cylinder heads where not used since the ports are huge. We focused on velocity so we went with a smaller head and worked it to get us the desired port volume and matched them to the intake.
Once that was done we started the design of the intake system which
used velocity stacks going into a common plenum made of carbon fiber. We also determined that the fuel required a big injector so instead of using just one we installed 2 injectors per cylinder which measured 110 lbs/hr.
After that was done we put the whole assembly on a flow bench to measure what we had and to make any improvements that we could. After gathering the data we used it to have a Custom camshaft made for our engine. Having this data is critical for proper cam design as you want to know what the valve sees with the whole system together, intake and exhaust. That way you can get the most out of your package, otherwise it will not be optimized for what you have done. The followers where all coated DLC to improve on longevity and to minize friction as well. The rings on the pistons are NPR rings and the material for the top ring is tool steel.
The cylinders are Mahle race cylinders. Tried iron sleeves as well. Work good but Mahle is easier to get.
The exhaust was completely hand made for the application since it is not something you can buy off the shelf. The primaries are 2" and end in a 3 into 1 merge collector from Burns stainless. The wastegates are 2 44mm Tials and the turbos are Garrett twin ball bearings. There are two intercoolers since the car design will allow for better flow that way. These were fabricated and spec for the engine. There where so many parts that had to be made to do the whole job, countless ours. We even incorporated a DBW to do the throttle actuation. After proving a bit slow in response we removed it for a cable style. The engine has a sequential trans attached to it with a custom Paddle Shift kit that we design and built. Hope this is a good description of what we did. We still have parts to build a couple more, any takers.
Respectfully
Ivan
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