Renntech 82mm throttle bodies
12-30-2010, 12:45 AM
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Vath ML63 Brabus C63 SL63 CLK63BS C63BS
Renntech 82mm throttle bodies
Did anybody see that Renntech released new 82mm throttle bodies for 63 engine about 2 weeks ago? They claim 11hp improvement at cost of $4000.
I recently had my SL63 dynoed and noticed that the throttles are never open more than about 70%. Can some one explain why a larger throttle body is needed when the stokc throttles are never opened anywhere near 100%. Custom tune altering throttle openings would be better wouldnt it??
I recently had my SL63 dynoed and noticed that the throttles are never open more than about 70%. Can some one explain why a larger throttle body is needed when the stokc throttles are never opened anywhere near 100%. Custom tune altering throttle openings would be better wouldnt it??
12-30-2010, 01:02 AM
#2
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My guess is that the stock throttle bodies will never open up to a full 100% even with a tune. The larger TBs opening at 70% will simulate a 100% opening of the stock TB size. That is my uneducated theory.
12-30-2010, 01:10 AM
#3
I don't know about an SL63, but I find it very strange that an SL63, which is rated at 518 hp (I believe) only opens 70%.
I'm not doubting TS's findings, I'm just curious why the SL's engine opens 70%, and my stock C63's TB's opened 62% (if I remember correctly), and a tuned C63's TB's are supposed to open 87%.
So much confusion.
Maverick, regarding the larger TB's, the theory is (as was explained to me by Andy at MHP--he wasn't necessarily speaking about TB's), with the M156 being N/A and there being a genuine limit to the kind of engine building that can be done at this point, you really have to work for every extra hp; especially, if you plan on staying bolt-on. So, in that sense, installing some larger TB's can increase the breathing of the engine (usually at higher rpms, I imagine) and allow it to make more power.
But, I don't know how the power band is affected, and I would be very curious about low-end torque.
Anyway, if you have the coin, and you found that the installation of the larger TB's on this car -- that doesn't have more aggressive cams and better flowing heads -- affects the power band to your liking, then it could be a good buy. But, 11 hp (flywheel or rear wheel?) for 4K is not worth it in my opinion.
Last edited by SonnyakaPig; 12-30-2010 at 01:26 AM.
12-30-2010, 01:48 AM
#5
I've asked before, but I don't remember the answer. I'd love to know though.
I'm guessing it's not necessary.
Here's a theory (just a theory): maybe the TB's opening 100% affects the AFR negatively. Maybe makes things too lean. I really don't know.
I'm guessing it's not necessary.
Here's a theory (just a theory): maybe the TB's opening 100% affects the AFR negatively. Maybe makes things too lean. I really don't know.
12-30-2010, 08:15 AM
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A tuned "63" engine will open the T/B's more than stock as needed to produce more power. What Andy was saying is that our engine will only ingest a certain amount of air and the throttle bodies at 87% or more is sufficient for way more power than we are making now. He was not saying that larger throttle bodies would make more power. To answer your question they are not necessary. AMG is using the throttle body and exhaust as a tuning agent.
My concern would be air flow, velocity, and torque. When the opening gets too large and the air allowed to pass through is not sufficient the velocity drops and thus so does the torque. Picture a 4" pipe flowing the same amount of water as a 3" pipe. They are both flowing the same amount of water but one has more velocity when the water leaves the pipe. I know thats over simplifying it but you get my point.
My concern would be air flow, velocity, and torque. When the opening gets too large and the air allowed to pass through is not sufficient the velocity drops and thus so does the torque. Picture a 4" pipe flowing the same amount of water as a 3" pipe. They are both flowing the same amount of water but one has more velocity when the water leaves the pipe. I know thats over simplifying it but you get my point.
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12-30-2010, 12:57 PM
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even with the t/b bored out, i would think that you would also need to port match to the intake manifold in order for it to make any significant changes.
my theory with the various range of t/b opening is:
regulation of a/f ratio to limit hp between the c63..sl63 etc.
like Dad C63 has stated: only so much air can be ingested with oem internals. of course this can be change with larger lob cams, larger valves,.. ported heads and so on without getting deeper into this conversation.
i wonder if these are tapered or a straight through design..
my theory with the various range of t/b opening is:
regulation of a/f ratio to limit hp between the c63..sl63 etc.
like Dad C63 has stated: only so much air can be ingested with oem internals. of course this can be change with larger lob cams, larger valves,.. ported heads and so on without getting deeper into this conversation.
i wonder if these are tapered or a straight through design..
12-30-2010, 02:31 PM
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12-30-2010, 02:40 PM
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A tuned "63" engine will open the T/B's more than stock as needed to produce more power. What Andy was saying is that our engine will only ingest a certain amount of air and the throttle bodies at 87% or more is sufficient for way more power than we are making now. He was not saying that larger throttle bodies would make more power. To answer your question they are not necessary. AMG is using the throttle body and exhaust as a tuning agent.
My concern would be air flow, velocity, and torque. When the opening gets too large and the air allowed to pass through is not sufficient the velocity drops and thus so does the torque. Picture a 4" pipe flowing the same amount of water as a 3" pipe. They are both flowing the same amount of water but one has more velocity when the water leaves the pipe. I know thats over simplifying it but you get my point.
My concern would be air flow, velocity, and torque. When the opening gets too large and the air allowed to pass through is not sufficient the velocity drops and thus so does the torque. Picture a 4" pipe flowing the same amount of water as a 3" pipe. They are both flowing the same amount of water but one has more velocity when the water leaves the pipe. I know thats over simplifying it but you get my point.
What I was trying to say was that with our motor, you really have to work for every extra hp. So, when a product is claimed to increase hp by 11, then that can be a good thing and actually a necessary thing if you're trying to gain as much power as you can, while you stay N/A. And especially so, if you're just staying with bolt ons.
I cited Andy because he provided that concept to me. It wasn't an original thought of mine so I wanted to give credit.
I do understand and have read Andy's thoughts on the TB's and that they are not necessary.
I also understand your good example of velocity and how too large of an opening can lower air velocity and for an intake that has TB's that already flow more cfm in stock form than a stock long block can even ingest, these larger TB's make little sense.
But, I was just trying to play the devils advocate and explain why people might look to these TB's to gain that extra 11 hp.
12-30-2010, 03:25 PM
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I understand your points. And I understand how my previous post where I mentioned "Andy" could be misinterpreted.
What I was trying to say was that with our motor, you really have to work for every extra hp. So, when a product is claimed to increase hp by 11, then that can be a good thing and actually a necessary thing if you're trying to gain as much power as you can, while you stay N/A. And especially so, if you're just staying with bolt ons.
I cited Andy because he provided that concept to me. It wasn't an original thought of mine so I wanted to give credit.
I do understand and have read Andy's thoughts on the TB's and that they are not necessary.
I also understand your good example of velocity and how too large of an opening can lower air velocity and for an intake that has TB's that already flow more cfm in stock form than a stock long block can even ingest, these larger TB's make little sense.
But, I was just trying to play the devils advocate and explain why people might look to these TB's to gain that extra 11 hp.
What I was trying to say was that with our motor, you really have to work for every extra hp. So, when a product is claimed to increase hp by 11, then that can be a good thing and actually a necessary thing if you're trying to gain as much power as you can, while you stay N/A. And especially so, if you're just staying with bolt ons.
I cited Andy because he provided that concept to me. It wasn't an original thought of mine so I wanted to give credit.
I do understand and have read Andy's thoughts on the TB's and that they are not necessary.
I also understand your good example of velocity and how too large of an opening can lower air velocity and for an intake that has TB's that already flow more cfm in stock form than a stock long block can even ingest, these larger TB's make little sense.
But, I was just trying to play the devils advocate and explain why people might look to these TB's to gain that extra 11 hp.
