Kriston

Whats up gents,

In my quest of building a true bolt on N/A Beast, my focus has shifted to larger throttle bodies.

I have been researching for a few days, trying to find some circumstantial proof that the larger TB's actually provide a bump in HP / TQ. Theres very little information available on them and the effects of them on the C63.

I have already weighed the pro's and con's of adding a larger throttle body system to the car. I am also aware that the stock dual 72MM TB's flow at well over 1300 CFM. Which is more then enough for a full bolt on C63.

I am panning over the details on The Renntech Dual 82 MM Throttle bodies. Renntech claims 11WHP and 8 WTQ gains. I don't doubt Renntech's numbers, but I'm more curious about the driving dynamics of the car after.

From my general knowledge of increasing the size of the TB's, I should expect a quicker throttle response. Of course more airflow means more power / tq. But thats not all that I'm after.

I wanted to build a N/A beast because the love i have for this car in N/A form far outweighs me wanting more power. I am more focused on overall driving dynamics. I love the extremely linear power delivery the car has now.

Wanted your take on them? For an every day street car I would enjoy a quicker response. would you?

If any of you have experience with larger TB's on the M156, your input is most welcome.

http://www.renntechmercedes.com/www/node/192#



Cheers fellas,

TexasEngineer

I doubt there are many people here (or anyone) with direct experience with larger throttle bodies on an naturally aspirated M156. I also further doubt Renntech's claims of 11hp. The M159 uses the same throttle bodies and can support more that 622hp NA. They are simply not a limiting factor. I would have to run the calcs, but they could be limiting factor for the supercharged engines. That also seems likely, becasue I don't believe Wiestec sells a larger throttle body upgrade. It seems to me that DadsC63 (Keith I believe) had the highest hp NA M156. He had port heads (minimal gain) and camshafts. I am not sure how the camshafts turned out. He and his tuner spent a lot of time trying to get that figured out and working properly. The bottom line is that you are highly unlikely to see any gains from the larger throttle bodies.

There may vary well be a change to the throttle response though. That being said, if you are seeking are quicker more linear throttle response, I would work with someone like Eurocharged to customize the throttle on the tune. It is all fly by wire, so you should be able to make the throttle response exactly the way you want to be.

Good luck on on you endeavor to to achieve more naturally aspirated horsepower. I think it is truly a worthy cause, and I champion it. I just think throttle bodies are a dead end. Any meaningful increase will come from changes to the heads and camshafts otherwise you will be looking at increasing displacement or possibly increasing compression. AMG didn't leave a whole lot on the table other than bolt on exhaust improvements.

Merc63

I hope you have lots of money, to squeeze the m156 NA you're going to need it.

SLS intake, camshafts, ported heads, exhaust and custom tuning.

mr747

Kriston

Why not nos?? ive read alot of threads that say the m156 loves it?

Kriston

Thanks for your input, I am somewhat skeptical about taking the plunge on the TB's. However, having experience with some Renntech product in the past and having the intakes on the C63 already. They do actually make the power they claim. Despite the general consensus on the boards, the Renntech intake actually made 9 WHP on my car. Renntechs reputation is long tied with AMG, heck Renntechs engineering team is located at the ring in Germany. I would hate to think they would release a product for 4K that didn't make its claimed power.

I have a custom tune on the car as well, as with many aftermarket tunes. The TB's on the car are mapped to open fully as opposed to 75% or so on the stock maps. from a tuning perspective I thin we have exhausted all other options.

Merc, its a long but steady journey my friend. I have managed to complete all the exhaust work this year along with Tuning and the Renntech intakes. The TB's are the next thing on my check list. I may consider working on the heads when I upgrade the bolts. But for now Im trying to learn / build as we go. I told myself 500 WHP N/A on this car will be immense fun.

Hey buddy, hope all is well. I have never really considered going with a Nitrous setup. I guess I'm heading for an overall build. Not necessarily only race / track oriented. For what i use it for, i don't think I can appreciate all what NO2 has to offer.

Theres a part of me that wants to take the plunge, simply because of the allure behind the TB's. Its not a ventured path for many, theres that big question mark of what if this thing actually makes the power it states and also adds the benefit of a much quicker throttle response. Im attracted to the potential changes in the driving dynamics of the car. Hopefully it will be for the better.

ruey220

before you start squeezing every ounce of power from the c63, see how much an exhaust makes a difference vs a stock one, or compare it to another c63 with same mods, do 1/4 mile, then do 0-100mph and 50-120mph comparisons. see how much difference in car lengths one mod like exhaust, or tune gives vs same car without that one mod, and see if the short term ego boost for for winning a race by half a car length on the road is worth $5k. if you find your car pretty same racing the same car with stock exhaust and your car has aftermarket free flowing exhaust to be the same, even the more the throttle body equipped modded car will be less of an improvement.

if you do it for competition or for work and you get paid or win a nice trophy for that .15 sec improvement over stock then $5k might be worth it, but for many $5k to be a legend in your own mind isn't worth it.

I only bring up this perspective is because from experience I realized I paid so much for upgrades and after recently comparing to another c63, it's not like our car is so much faster like you're comparing a p31 package vs non-p31 or like a black series vs a stock c63.

in fact the more I think about it the more I believe MB did try to squeeze as much out of the M156 with the C63 BS anything more is pretty much just paper number and hardly good for actual day to day road use. if you want an edge, you're probably better off reducing weight on the car to get better power to weight ratio, and bang for the buck. you can drop 250pounds+ on this car and keep it streetable.

Merc63

Removing some weight from the heavy girl works very well and is cheap too.

Kriston

This is Great Insight, and I agree with you whole-heartedly, I ran with another C63 post header install on my car. The Other C63 was just tuned. From a dig to 150KM / Hour I was actually surprised how close he was still. I was ahead a half car length the whole time, only really started to pull ahead close to the 150KM mark. With exhaust work, I think the benefits come higher up in the gearing. Perhaps our top speeds would be much different.

I digress, I have already invested quite a bit into the C63, at this point I'm doing this more for the love of the platform and to explore the limits of the M156 in N/A form.


This is a great idea as well, to cut 250 LBS means removing seats etc. Not sure I want to go that far for a summer only daily driver.


I had a call into Renntech yesterday, im working with Mark over there (who is quite helpful actually) to see some real world results from these things. I will post up what findings I come across.

Petakii63

I know renntech puts out top notch products and they will not sell something to affect the driveability of the car. However, I do believe you might lose a little low end power. But, the car will gain top end no doubt. To be honest after tb mod Kris. I don't think there is anything left that would be worth it power to money wise. Cams will definitely affect driveability. And, without proper tuning it could be a headache. Put it this way if you like the way your car is now. Don't fix something that isn't broken. Heads are a waste of money since DADSc63 only picked up 4-5 whp. Sls intake will need lots of modification to fit under the hood and also more tuning. AMG really went all out on this motor in N/A form

Kriston

Alright boys,


I managed to obtain the dyno graph from Renntech for the TB's. Blue curve is a stock C63 and the red curve is with the addition of the larger TB's.


So were looking at an 11WHP and 8 WTQ gain with factory exhausts and intakes.


Considering how well AMG designed these engines, the 11 WHP gain is huge considering Keith only managed to obtain 4-5 WHP with ported heads.


The plot thickens!


Im ... this close to pulling the trigger now.

rentzington

not terrible gains at all, there isn't a ton of meat left on the bone when it comes to bolt on parts for these engines.

To me that's not enough gain to justify the cost, but if you are happy with the price I say go for it.

mthis

Nice to see someone chasing high hp in NA form .
Saw u posted about Dads gains on the heads but i think the 5rw was with very different weather conditions. In this thread with similar condition pre install heads he gained almost 20rw on heads alone and if i remember correctly he gained another 25 with cams. https://mbworld.org/forums/c63-amg-w...omorrow-4.html
https://mbworld.org/forums/c63-amg-w...s-results.html

TexasEngineer

I still doubt the claims. It says a stock C63. Well if it is really stock, that would mean that the throttle bodies would not be open all the way. Stock throttle bodies on a C63 only open 75% to 80% or so. Adding larger throttle bodies would allow more air to pass through at part throttle. Thus the observed increase in HP on the stock C63. I don't believe these will add any HP to a tuned car.

mthis

c63 throttle bodys open 75-80% with stock tune with aftermarket tuning they open up close to 100%.

TexasEngineer

Yes, that is what I am saying. The car in posted dynograph is a stock car with partially opened TBs. Larger TB with partial opening will yield the a similar affect of opening the TBs further.

On a car with an aftermarket tune, the TBs will the 100% open and the larger Renntech TBs will yeild negligible gains.

mthis

Exacty.

TexasEngineer

Additionally if you are trying to squeeze every bit of HP out of the car possible. I would upgrade the headers you have. The AP headers are have smaller primaries than, the MHP, MBH, and Weistech. The larger primaries will yield more top end power and ultimately higher peak HP. The smaller diameter primaries will yeaild more low end torque, but less high RPM HP. You could also go to larger diameter mid pipes and cat back exhaust. The exhaust you have is only 2.75" in diameter. There are gains to be had with 3" exhaust.

chrisridebike8

Let me find the thread but I'm pretty sure Dads made 20 whp with heads/cams.

GRP

That saved me some time typing. They need to compare like with like.

chrisridebike8

Here is Dads thread. He said about 20 whp for heads/cams

https://mbworld.org/forums/c63-amg-w...ml#post3771052

mthis

My set up or Kriston ?

Either way. The AR headers are MHP i just have the 1st version the 1 7/8th instead of 2in primary. This is proven on track that its better for NA set up then the 2in primary , i personally drove my car and my friends a former forum member on here he had MBH at that time and the low end tq wasn't there with the larger primarys. But for FI the guys with superchargers love the 2in .

Merc63

Mhp v2 are 1 7/8 same as v1. The collector is larger though.

MHP are putting down just as much power as MBH in blower cars. I've proved this with my track times.

mthis

Good to know. For some reasonI thought it was 2in.

ruey220

i realized with NA cars that area already high output from the factory like AMG, there's very little HP you can squeeze out. I've noticed BMW M power cars have a far more distance you can stretch them because they are from a racing platform config that you can open up. True the C63 from detuned form to fully opened form it goes a long way, but once you're already up there there's very little you can do. Maybe it is because AMG engines are already hand built and inspected for marginal tolerances vs M cars I've seen some that you can go from 380 to 500HP without force feeding the motor.

mr747

IM sure if you have enough money you can get SLS performance/horse power from the m156
Ive seen guys in Germany putting SLS intake manifolds on the m156 i guess its down to how much money you want to spend