Supercharger for AMG 63s (M156)
Oh, and yes there are ways other than the right way!! You can dump fuel in the a/f and make it super rich. You can use a thicker head gasket. You can run higher octane (technically, I guess this is a right way, but then not very practical). You can mount the supercharger on the side of the engine to avoid having to do a custom manifold. Lots of things and unfortunately high end tuners aren't immune. I don't know Vadim, but was reacting to the idea of putting a twin screw on a 11.3:1 CR engine.
I am interested but with some caveats because I would only do it if its done the right way - which is very hard. I have done a custom twin screw before and that is definitely the right choice for this big engine (don't even think about a centrifigal or turbo with this size engine). 700+ whp (dyno) is very realistic and would be worth $10-15K grand (my estimate of end cost in volume with pistons, supercharger, manifold and tune). Install is probably another 2-3K. Yes, expensive but so is the car.
So, here is what I want to see and why:
1) You have to get low comp pistons made or else the project isn't worth it. At 11:1, you have no breathing room. Sure, you can try to stay safe by limiting boost to 3-4 pounds, but even then you will have to detune the engine (to make the a/f pig rich to avoid blowing the engine). Maybe you get 70, maybe not; but I promise you the detuning required will kill gas mileage and your torque curve will look bad. And you may blow a few engines before you get it right - a very expensive R&D project. In any event, with this compression and a supercharger, the car will not perform the way it was intended to across the entire curve. Low comp pistons will add a couple grand to the project but the benefits in terms of range of tune and ability to really use the supercharger in the range it was intended will far outweigh the cost. I would go with 9.5:1 - that should allow 10-12 pounds and get you to 600-700whp (a very rough off the cuff estimate) with very little risk, and at 9.5 you still have a very responsive efficient engine. Below 9.5 you probably want a custom cam grind and that gets $$$$$.
2) You have to get a custom tune for this because you need more fuel in at a minimum. Maybe the motec will automatically compensate, but I wouldn't want to bet on that.
3) As others have noted, you want to do an intercooler (although may not be needed with modest boost; hard to say with such a high comp engine what would happen without it). Under my high boost scenario, an IC is an absolute must. Autorotor makes a very nice air-water IC in tubes that can (and should) be integrated into the intake manifold. The tubes are relatively cheap (the custom manifold, maybe not so cheap).
4) To make a good size twin screw fit, you are going to need a custom manifold and place the twin screw in the V. The manifold will be the hardest part in my opinion.
Some additional comments:
1) I think most of us who paid 100K for our car are going to want this done absolutely right. A $10K spend to get a couple hundred more HP is a good trade if its safe, tested, and corners are not cut. So don't cut corners, and do it the way I suggest.
2) Kenne Belle is great but unless they are going to provide the whole package (manifold, pistons, and tune), I would go straight to autorotor and get your superchargers. You get more options (sizes and bypass options) vs. KB, but more importantly KB is just going to mark up on top of your markup (or the other way around) and make the project unnecessarily expensive. KB gets their sc from autorotor as I recall, so should you unless KB is providing some really serious value add. Otherwise, your cost is going to skyrocket.
3) If you insist on going without low comp pistons, don't bother with a twin screw. If you look at the psi x efficiency charts, you will see that in the low psi range, there is not that much difference between a twin screw vs. the cheaper eaton supercharger. Might as well go cheap if you are going cheap!
4) At the power I am contemplating, a quaife ATB is pretty important and unfortunately not included on the car. Might want to set up a joint buy program or offer a discount through them. Just an idea.
However, please read the whole thread, almost all of your questions have been addressed before.
This will likely be a Stage I, where it is an easy bolt on and can be reversed. Over 90% percent of AMGs are leases and an easy reversibility of the mod is extremely important.
Stage II will produce higher boost and will require low compression pistons. That will be aimed at more dedicated owner who is likely to keep the car for some time.
This will likely be a Stage I, where it is an easy bolt on and can be reversed. Over 90% percent of AMGs are leases and an easy reversibility of the mod is extremely important.
My concerns if you start out with the Stage 1 -> Stage 2 approach:
(a) if you are designing with Stage 2 in mind, you need a pretty big blower so that (in Stage 2) you are going to be able to hit 10+ pounds on a 6.2+L engine without moving into the very high rev (lower efficiency) territory of the blower - unfortunately, such big blowers are going to cost you in $$ and in Stage 1 will rob power,
(b) are you going to design the manifold to accomodate the IC or will you have to modify the Stage 1 manifold to add an IC (or, if an IC is in Stage 1, do you need a bigger one that requires manifold changes)
(c) will you really get 70wp/70tq across the curve without sacrificing (losing power or torque) in some other parts of the curve
(d) will it make any difference in the quarter mile (my gold standard for whether a mod really improved things, regardless of what the dyno says) (I bet not)
Of course, you could avoid these problems and go with a smaller blower that is designed for 3-6 pounds, maybe even without an IC at 4 pounds, and then completely redo the project for Stage 2. That, however, doubles R&D and significantly increases materials costs.
In sum, I guess the tradeoffs from Stage 1 -> Stage 2 could be very significant as opposed to going right to Stage 2.
The Best of Mercedes & AMG
and then they would probably upgrade. But, I am pretty sure that someone's who works on Ferrari's and other high end Autos knows what he is doing
The nature of centrifugal blowers is parabolic, meaning at half the redline rpm, you make less than half of the boost. So how is it even possibly to achieve a spike in horsepower when max boost hasn't been reached until redline?
In my experience screw type blowers are close to turbos, they both build boost down low (the screw even lower) but at the top end screw compressors lose efficiency where turbos keep steaming ahead.
What exactly do you mean by compensate? Compensate what/for what?
Last edited by msheredy; Sep 24, 2007 at 07:38 PM.
My concerns if you start out with the Stage 1 -> Stage 2 approach:
(a) if you are designing with Stage 2 in mind, you need a pretty big blower so that (in Stage 2) you are going to be able to hit 10+ pounds on a 6.2+L engine without moving into the very high rev (lower efficiency) territory of the blower - unfortunately, such big blowers are going to cost you in $$ and in Stage 1 will rob power,
(b) are you going to design the manifold to accomodate the IC or will you have to modify the Stage 1 manifold to add an IC (or, if an IC is in Stage 1, do you need a bigger one that requires manifold changes)
(c) will you really get 70wp/70tq across the curve without sacrificing (losing power or torque) in some other parts of the curve
(d) will it make any difference in the quarter mile (my gold standard for whether a mod really improved things, regardless of what the dyno says) (I bet not)
Of course, you could avoid these problems and go with a smaller blower that is designed for 3-6 pounds, maybe even without an IC at 4 pounds, and then completely redo the project for Stage 2. That, however, doubles R&D and significantly increases materials costs.
In sum, I guess the tradeoffs from Stage 1 -> Stage 2 could be very significant as opposed to going right to Stage 2.
Adding 70HP/70TQ will drop ET by at least 1/2 sec. and add 5 mph at the top. For most 63 owners that will be enough, for those who want to go further, Stage II will offer a further step.
I do appreciate your concerns, but I will not release this kit until I am 110% certain that it will be worth spending money on.
I am interested but with some caveats because I would only do it if its done the right way - which is very hard. I have done a custom twin screw before and that is definitely the right choice for this big engine (don't even think about a centrifigal or turbo with this size engine). 700+ whp (dyno) is very realistic and would be worth $10-15K grand (my estimate of end cost in volume with pistons, supercharger, manifold and tune). Install is probably another 2-3K. Yes, expensive but so is the car.
So, here is what I want to see and why:
1) You have to get low comp pistons made or else the project isn't worth it. At 11:1, you have no breathing room. Sure, you can try to stay safe by limiting boost to 3-4 pounds, but even then you will have to detune the engine (to make the a/f pig rich to avoid blowing the engine). Maybe you get 70, maybe not; but I promise you the detuning required will kill gas mileage and your torque curve will look bad. And you may blow a few engines before you get it right - a very expensive R&D project. In any event, with this compression and a supercharger, the car will not perform the way it was intended to across the entire curve. Low comp pistons will add a couple grand to the project but the benefits in terms of range of tune and ability to really use the supercharger in the range it was intended will far outweigh the cost. I would go with 9.5:1 - that should allow 10-12 pounds and get you to 600-700whp (a very rough off the cuff estimate) with very little risk, and at 9.5 you still have a very responsive efficient engine. Below 9.5 you probably want a custom cam grind and that gets $$$$$.
2) You have to get a custom tune for this because you need more fuel in at a minimum. Maybe the motec will automatically compensate, but I wouldn't want to bet on that.
3) As others have noted, you want to do an intercooler (although may not be needed with modest boost; hard to say with such a high comp engine what would happen without it). Under my high boost scenario, an IC is an absolute must. Autorotor makes a very nice air-water IC in tubes that can (and should) be integrated into the intake manifold. The tubes are relatively cheap (the custom manifold, maybe not so cheap).
4) To make a good size twin screw fit, you are going to need a custom manifold and place the twin screw in the V. The manifold will be the hardest part in my opinion.
Some additional comments:
1) I think most of us who paid 100K for our car are going to want this done absolutely right. A $10K spend to get a couple hundred more HP is a good trade if its safe, tested, and corners are not cut. So don't cut corners, and do it the way I suggest.
2) Kenne Belle is great but unless they are going to provide the whole package (manifold, pistons, and tune), I would go straight to autorotor and get your superchargers. You get more options (sizes and bypass options) vs. KB, but more importantly KB is just going to mark up on top of your markup (or the other way around) and make the project unnecessarily expensive. KB gets their sc from autorotor as I recall, so should you unless KB is providing some really serious value add. Otherwise, your cost is going to skyrocket.
3) If you insist on going without low comp pistons, don't bother with a twin screw. If you look at the psi x efficiency charts, you will see that in the low psi range, there is not that much difference between a twin screw vs. the cheaper eaton supercharger. Might as well go cheap if you are going cheap!
4) At the power I am contemplating, a quaife ATB is pretty important and unfortunately not included on the car. Might want to set up a joint buy program or offer a discount through them. Just an idea.

Thanks
Brad

Good luck!
There is a huge misconception that boost and high CR is a bad idea. And that is false. Its high CR with pump gas that is a bad idea. Two cars with identical setups except one running 10.0:1 and another running 11.5:1, the higher CR car will more power/tq assuming enough octane is available.
This will be an expensive project. Who ever can afford to get this done should have no problem paying $7/ gallon for some Sunnoco GT104 gas. Hell pump gas is almost $4/gallon anyways. You've got to pay to play. I would say 5psi with spot on tune (NOT MAIL AWAY TUNE), higher boost with unleaded race gas and you should see a significant gain.
To give you an idea of what is being done:
- CLK BS widebody panels
- Custom dual exhaust
- VRP 63 headers
- VRP S/C upgrade (first pass will be for stock internals.. second pass will be higher boost and built bottom end.
)- VRP VR530 Kit
- VRP 63 Coilover kit
- VRP 2piece brake upgrade kit
- Quaiffe LSD setup
- Custom wheels (havent decided on which ones yet)
There is a bunch more going into it, but the S/C is the first R&D project Vadim will be tackling.
We'll post progress of the project car as we move along.


