Supercharging a S600 V12 coupe w140
Discussion
Hi@all,
I just wanted to hear your comments about following idea that I have in mind for quite a time.
Playing around with the plan to supercharge my S600 coupe model 93 i plan to go following way:
As space in the engine bay of the V12 is very limited I want to replace the stock secondary air pump with a s38 Rotrex unit mounted on a custom made bracket + air/air intercooler (front mounted). The pump is larger than the rotrex so enough space should be available.
The Rotrex and the pump are using an 8 v rib with a PK-profile so this could work inline with the other stuff (A/C pump , pas pump, aso.).
I want to achieve a power gain of around 100 hp, stock comp.ratio (10:1) should be maintained. Therefore I am heading for a 5-7 psi setup.
Some questions that came up:
- Has anybody heard about such a conversion or has some experience in supercharging a v12/V8 Merc. engines.
- Is it possible to arrange the charger inline with the mentioned other units (a/c, pas) or is a direct driveline
to the crank required ? If possible do I need another rib tensioner directly positioned on the custom bracket or
is the stock tensioner doing the job.
I do not want to go the twin supercharger road because I want to hold the setup as simple as possible.
Setup: supercharger->intercooler->split hosesto the two throttle bodies
Associated hardware stuff: custom bracket, oil circuit supercharger (cooler, filter), air filter, pop off vent, (rib tensioner), custom hoses, plumbing, fasteners
As the V12 has a very advanced ignition and fueling system (Bosch LH-jetronic) a comp. ratio of 10:1 and unique knock sensor control for each single cylinder I think it could be a good basis for a light supercharge tuning.
I am curios to hear your comments and would be glad if we could start a fruitful discussion.
Regards
Stefan Rupp
I just wanted to hear your comments about following idea that I have in mind for quite a time.
Playing around with the plan to supercharge my S600 coupe model 93 i plan to go following way:
As space in the engine bay of the V12 is very limited I want to replace the stock secondary air pump with a s38 Rotrex unit mounted on a custom made bracket + air/air intercooler (front mounted). The pump is larger than the rotrex so enough space should be available.
The Rotrex and the pump are using an 8 v rib with a PK-profile so this could work inline with the other stuff (A/C pump , pas pump, aso.).
I want to achieve a power gain of around 100 hp, stock comp.ratio (10:1) should be maintained. Therefore I am heading for a 5-7 psi setup.
Some questions that came up:
- Has anybody heard about such a conversion or has some experience in supercharging a v12/V8 Merc. engines.
- Is it possible to arrange the charger inline with the mentioned other units (a/c, pas) or is a direct driveline
to the crank required ? If possible do I need another rib tensioner directly positioned on the custom bracket or
is the stock tensioner doing the job.
I do not want to go the twin supercharger road because I want to hold the setup as simple as possible.
Setup: supercharger->intercooler->split hosesto the two throttle bodies
Associated hardware stuff: custom bracket, oil circuit supercharger (cooler, filter), air filter, pop off vent, (rib tensioner), custom hoses, plumbing, fasteners
As the V12 has a very advanced ignition and fueling system (Bosch LH-jetronic) a comp. ratio of 10:1 and unique knock sensor control for each single cylinder I think it could be a good basis for a light supercharge tuning.
I am curios to hear your comments and would be glad if we could start a fruitful discussion.
Regards
Stefan Rupp
Hi@all,
thanks for your comments.
The s38 is the biggest unit available and can support from 400 to 630 hp supercharged.
I want a gain of 100 HP over the stock 397 HP therefore around 6-8 PSI (0,3-04 bar) should be already enough and the stock fuel system should be still capable of supporting this relatively low boost level with a rolling road chip tuning.
Belt tension and slip might be the biggest problem. I am not quite sure if the rotrex centrifugal unit absorbs between 20 to 30 hp under full boost compared to a twin screw charger that has a lot more inner friction than the smaller rotrex unit. Would be interesting to know if there is a calc. formula where you are able to calculate the belt tensioner force related the charger moment to know if the stock tensioner can do the job or if there is another one necessary.
Thanks for the tip with 150 degree cover angle on the pulley. This would have been one of my next question. Is this the absolut minimum ? 180 degree might not possible given the location of the rotrex in this setup.
Cheers
Stefan
thanks for your comments.
The s38 is the biggest unit available and can support from 400 to 630 hp supercharged.
I want a gain of 100 HP over the stock 397 HP therefore around 6-8 PSI (0,3-04 bar) should be already enough and the stock fuel system should be still capable of supporting this relatively low boost level with a rolling road chip tuning.
Belt tension and slip might be the biggest problem. I am not quite sure if the rotrex centrifugal unit absorbs between 20 to 30 hp under full boost compared to a twin screw charger that has a lot more inner friction than the smaller rotrex unit. Would be interesting to know if there is a calc. formula where you are able to calculate the belt tensioner force related the charger moment to know if the stock tensioner can do the job or if there is another one necessary.
Thanks for the tip with 150 degree cover angle on the pulley. This would have been one of my next question. Is this the absolut minimum ? 180 degree might not possible given the location of the rotrex in this setup.
Cheers
Stefan
TR7V8,
thanks for the effort.
The max flow rate of the C38-81 Rotrex is 0,55 Kg/s @15 degree C and 0,1013 mPa, that equals to 72,753 lbs/min.
Here is the link to the tech. spec. of the rotrex I have in mind.
Hhttp://www.rotrex.com/pdfs/Rotrex_Technical_Datasheet_C38_Range_V4.0.pdfi
There is also a conversion formula from Kg/S to CFM (?).
May be this can tell you a bit more than me.
Just going to order this book :-).
Cheers
Stefan
thanks for the effort.
The max flow rate of the C38-81 Rotrex is 0,55 Kg/s @15 degree C and 0,1013 mPa, that equals to 72,753 lbs/min.
Here is the link to the tech. spec. of the rotrex I have in mind.
Hhttp://www.rotrex.com/pdfs/Rotrex_Technical_Datasheet_C38_Range_V4.0.pdfi
There is also a conversion formula from Kg/S to CFM (?).
May be this can tell you a bit more than me.
Just going to order this book :-).
Cheers
Stefan
Edited by srupp1969 on Thursday 10th January 11:29
Edited by srupp1969 on Thursday 10th January 11:33
Thanks guys for all your efforts.
I go and talk with the mentioned people at TTS and the US-Company to gain some more information about the right setup and the limitations.
If you want I am always open to discuss a different solution (Vortech for example), but I suppose it will be a centrifugal charger setup due to space and boost characteristic (the stock engine has already got 570 NM of torque over a low rpm range).
Btw: Rotrex page (Rotrex.com)says that the C38-81 headunit is well suited for engines from 3-6 litres displacement and from 400 to 690 HP.
I will find out.
Cheers
Stefan
I go and talk with the mentioned people at TTS and the US-Company to gain some more information about the right setup and the limitations.
If you want I am always open to discuss a different solution (Vortech for example), but I suppose it will be a centrifugal charger setup due to space and boost characteristic (the stock engine has already got 570 NM of torque over a low rpm range).
Btw: Rotrex page (Rotrex.com)says that the C38-81 headunit is well suited for engines from 3-6 litres displacement and from 400 to 690 HP.
I will find out.
Cheers
Stefan
Edited by srupp1969 on Thursday 10th January 13:30
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