Just got back from the shop and The AMS pulley is installed and before and after same day dynos run. First things first stock pulley in my C55 was 6.6LBS and the AMS pulley was 2.8lbs The construction of this pulley is top notch to say the least. Peak HP didnt really change much but i picked up 15-10tqs though out the RPM range and about 10hp though out the RPM range. I cant give a full review on it yet as its not even drive 30miles. But shifts are smoother thats for sure. I also was getting 24.8mpg and thats the best this car has ever done. Anyway here is the dyno with before and after runs on the same chart. sorry for the large image kinda makes it abit easier to read

 

I'll have to say- I never would have thought it would make that difference. That's pretty darn good. What was the cost of the pulley? Is there direct access from the top or did you have to get replace it from under the car?

 

Thanks for the dyno's. Nice to see dyno graphs from the same day on the same dyno. I may be wrong but I think this is the first set of back to back dyno pulls for the AMS pulley. Pretty impressive #'s. I may just have to order one of these sooner rather then later.

 

sweet dude!

 

They put it on the lift because they had one it took two people at times one to hold the flywheel??? and one on the pulley. It also took two people to torque it down again one on the flywheel and one on the pulley other than that it took about an hour total install time. pulley cost $499 from LET motorsports. Needless to say the guys at Dyno-comp were i got it installed were amazed at how light and nice the pulley was. Anyway big shout-out to LET Motorsports and AMS for a great product. At $499 for the power its one of the better mods out there, granted I have Airbox, headers, ECU so gains could be different.

I should not more than one dyno run is needed. Car lost 25 peak HP on first pull and gained 25tq. then after what we thought was Mercedes adapting to the new part it worked itself out and HP came back.

 

I might have to head back to the drags and see what i can do.

 

Thanks for another great non-biased review! It appears to be a good, safe and relatively inexpensive mod to do and now we have some concrete evidence that it works! So, a question to you hooleyboy - what do you feel had made the most difference or was the most worthwhile mod? In regards to heading back to the drags, I would love to see you go up against the new M3!

On a side note, perhaps with the interest you've ignited in this forum with these products for the C55 it might be a good idea to get a few group buys going....just a thought!

 

They all felt good IMO. I started with just an ECU, and that felt killer, when when i went to the Headers and airbox the car just came alive. the kick down and go is amazing at times, (adaptive trans can get in the way sometimes.) The pulley just seemed to bring all the mods together by smoothing out the shifts. On cold nights I swear this thing is putting down 340HP and 350tq. Let it be noted it was 105 degrees out today when I dyno'ed before and after. Until I can get into the 12's the new M3's got me beat for now. love to race one though and the new C63 as there was another on in the shop today that only put down again 330whp! I will get a print out of the run for you all to see.

 

Once again props Hooleyboy!

 

Just wait, you should pick up a few more poneys as the ECU adapts more (usually by 7th day its full adapted). Definitely very impressive numbers, but that doesn't even compare to the M104 crank pulleys . Do you have a higher resolution scan of the picture? what are the actual peak torque numbers before & after?

The reason max peak HP doesn't change that much is crank pulleys work as a function of torque, not rpms (like accessory pulley kits). Max gains are always at max peak cylinder pressures (aka max torque), by the time the engine gets to about 5500rpm the torque curve is dropping quickly and as a result the HP gains drop a well. They make amazing mid range gains in both full and part throttle and improve fuel efficiency quite a bit. From idle to the last 1000rpm the crank pulley does wonders but above that the engine is spinning so fast that the differences in inertia between the stock pulley & AMS pulley becomes less and less. For the last 1000 rpm you need e\/osport accessory pulleys, they really only make all their power in the last 1000rpm, crank pulley the opposite. together they make an amazing combo and improve the entire power band a substantial amount. I must say though, that torque curve on your car is as flat as the great plains, must feel nice.

Congrats on your new mod. enjoy it.

 

thanks for the review. i was on the fence about one of these but will have to pick on up!

 

Whats nice about these kinda of mods is the flatten out the HP though the RPM range and lift the TQ as well so if you can make peak HP longer thats a good thing I would think. if you look at the dyno chart between 5500-6000RPM's peak HP is happening 500RPM's sooner and holding until 6000RPM's rather than just peaking at 6000RPM's Maybe to tie this into my other thread about carbon fiber drive shafts. but i would bet that a CF driveshaft would help flatten the HP curve out even more.

 

Carbon driveshaft work as a function of rpms so technically they should make max gains at max rpm (aka redline). It will help level off HP and prevent it from dropping off, it should level off. Technically HP should never peak with a mod like that (in theory), now its difficult to say exactly b/c its never been done on our cars. Again the gains probably will be around 6-10HP/tq depending, not as much as the crank pulley but it will definitely be one of those mods that make a drastic difference in the way the car feels & performs even though its not stellar on a dyno graph.



Here are typical benefits (taken from some cobra CF manufacturer's website):
"
All tube yokes are built from forgings specifically designed for carbon fiber applications. This carbon fiber driveshaft is a perfect answer to Long, High RPM, horsepower, torque applications. This Precision Driveshaft is a continuous filiment wound tube, Allowing Power to be transmitted from fiber to fiber to bring the following Advantages...

*Lighter than steel or aluminum.
*Three times torsional strength of steel.
*Torsional spring rate allows better tire hook-up.
*Torsional spring rate allows smoother shifting.
*Less shock load to the differential.
*Eliminates or dampens high speed vibrations.
*Reduces transmission and differential breakage.
*Characteristics can be varied by changing the wind, angles or diameter.
*In drag racing applications - a better 60 Ft. time.
*Better control out of corners is the result of the torsional spring rate.
*In road racing smoother shifting and better durability of transmission and differential have been reported.
*A much greater safety factor - carbon fiber will return to a fiber and not create shrapnel under the car, as would aluminum or a steel counterpart."

 

Hooleyboy,
When you say "same day dyno runs" what was the temperature and humidity difference between the runs if there was a morning and afternoon testing variance?

I respect the time and money you invest and share. The next comment has nothing to do with you personally but a general assessment.

I would think the most accurate way to tell if a part makes gains is a series of stock runs spread out to get an idea of an average. Then after a part is put on and the computer re-learns run a spread out serious of runs again and see if the average is up overall.

I would think this is what the tuners are doing but many people don't believe them yet no one person is spending the time and money to do it themselves so there is always skepticism about performance gains to clarify the truth.

 

Congrats on the gains Hooleyboy! And to reiterate what everyone else has stated I do appreciate your non biased reviews. I'm starting to get an itch to mod my car now.

 

to answer a few questions asked (not just the one im quoting) Temp at time of first dyno was 103 degrees at with a 1.6% adjustment (what does that mean IDK) second run (after pulley) was 105 degrees.

When we put the car on the dyno it was run about 5 or 6 times the first 3 times we seen a big jump in torque and mid rang HP and a hunge loss of top end peak Hp -25hp at redline. we all were lost for words as we thought it was a trade-off and just moving power gains around rather than gain anything over all. but what we saw for the next three runs was the computer fixing the problem and adjusting for the new part Mid rand torque and HP came down a bit and the my redline power was back. we did three pulls the first and third pull is what you are seeing in thew gains as they were just about exact. the second pull was a bit lower as the car was getting hot. we sat about 1 min between pulls. I dyno'ed at 331whp last Friday base line but was 328whp so it would be safe o say i gained 4whp at readline but who's going to feel that? Not to mention i did see a 1.5 miles per gallon gain over my best highway MPG ans that was 23mpg.

 

As the ECU adapts mpgs should move up close to the 2mpg mark and you should pickup up a little more. Either way those are about as accurate results as you could possibly get. Thx for the info Hooley.

 

I'm headed back to the strip for a few test runs tonight i will post my results if its worth it.

 

any drag strip results?

 

13.2 @ 108mph granted it was 101 degrees out when i ran that time. I ended up tieing my best time. my best time from before was at 60 degrees out stock. I bet i can get into the 12's on a cold or cool night. I was mostly running 13.4's at 108-109mph. some wheel spinning too.

 

I don't remember if I've asked this before but what tires are you running??

 

wow 101 is scorching hot haha. Ya I guess you'll have to wait for winter and break into the 12s.

 

I am running conti-sports and they suck. I got some mickey tompson's on the way for use at thr drags.

 

yeah no records are being broken in this kind of heat.

 

That's funny, I have conti-sports on mine also. Oh well, look at the brite side, one more trip to the strip and you will probably be in need of new ones and you can get something better....