Thanks Gustav. Has nothing to do with aerodynamics though since we started at 45 mph. I believe it comes down to the fact that the Dinan Stroker is making power when there's proper air flow.
Nice run, Darren; thanks for the vid! I think this might actually support Dinan's argument that a high flow fan is necessary for accurate dyno readings when looking at some of their mods. There is absolutely no way that your car is producing only 456rwhp. I am a bit concerned, however, as the stroker has dynoed much higher than that in the past. http://www.m5board.com/vbulletin/e6...122740-video-5-7-liter-stroker-v10-dynod.html
Anyway, this does go to show that real world results are ultimately those that really matter.
I hope you know that your vid has probably put me over the top and I will be planning on the stroker within the next 6 - 8 months (depending on how business is doing). Right now, this still looks like a doable deal for me. I was considering doing the stroker for my M5 or a Mopar hemi in my Jeep Rubicon. Coincidentally, approximately the same price for each of the upgrades. I will need to watch the vid a few more times before I call it a night. Excellent kill.
I am a little surprised you only made 456rwhp on a DynoDynamics when the CTS-V put down as much. I believe you put down 555rwhp on a Dynojet. I wouldn't have thought it would make 100rwhp less. Your M5 looks plenty strong on the video...so I am a little confused.
1. Classic BMW (a BMW dealer) had a "Dyno Day"
2. They use a Dynodynamics dynonameter (also used by RPI for example)
3. On Saturday, the 2009 CTS-V dyno'd and pulled 456 rwhp/450 rwtq
4. On Saturday, the 2008 Stroker M5 dyno'd and pulled 457 rwhp/330 rwtq (I posted an incorrect trq amount in the video)
Having done numerous dyno pulls now with my car I know it's making much more power on the road, so for grins me and the owner of the CTS-V decided to do 3 runs together. All 3 started at roughly 40-45 mph. My car has dyno'd 466, 500, 525, adn 557 rwhp at other times/locations/dyno types (mustang, dynapak, and dynojet).
I hope this helps to clear up any confusion. I made the video to show dyno numbers are extremely misleading in naturally aspirated cars without proper air flow. I am a firm believer now.
Forced Induction cars (Ford GT, CTS-V, etc.) are not impacted really on the dyno and show proper figures since the supercharger is forcing more air in regardless if the car is moving or not.
My Dinan Stroker M5 platform is predicated on having proper airflow (larger MAFs, larger air intakes, larger throttle bodies, larger displacement, etc.) and without real-world air flow my numbers are going to be way off.
Forced Induction cars (Ford GT, CTS-V, etc.) are not impacted really on the dyno and show proper figures since the supercharger is forcing more air in regardless if the car is moving or not.
Sorry Darren, this could explain what happened in your tests but unfortunately this is incorrect. Forced induction cars are even more adversely impacted by the lack of airflow on the dyno. I've had first hand experience with the 'running out of air' phenomena on the ICS dyno with my E39 M5-S3.
Steve Dinan has written about this in his paper "Dynamometer Testing and the Modern BMW Engine" excerpted below:
A lack of air-flow during dyno testing will almost always alter the fuel mixture in the rich direction as the radiator cannot exchange enough heat, resulting in the computer compensating by retarding timing and richening the fuel mixture to prevent the engine from overheating and detonating. In addition, the intake air sensor will read substantially higher temperatures than that seen on the road with proper airflow. This issue is particularly important to address when testing high output cars like the M5 or M3, and even more so on forced induction cars with intercoolers as the heat exchanger is not able to cool as efficiently because of the reduced air flow.[EMPHASIS ADDED] The engine compartment is normally flushed with air driving down the road, particularly at speed, cooling the manifolds and other associated engine components. Cooler engine components and lower air intake temperatures will result in a leaner air/fuel mixture and ignition timing will be advanced, invariably resulting in greater power on the road than on the dyno. In simpler terms, accurate measurements can only be achieved when the dyno tests are conducted in a manner that simulates the car driving down the road, in as much as is possible. <style>BODY { FONT-FAMILY:Verdana; FONT-SIZE:10pt } P { FONT-FAMILY:Verdana; FONT-SIZE:10pt } DIV { FONT-FAMILY:Verdana; FONT-SIZE:10pt } TD { FONT-FAMILY:Verdana; FONT-SIZE:10pt } </style><basefont face="Verdana" size="2">
what wheels were on the m5 when you ran it on the dyno? i know my buddys CLK Black Series lost around 25 rwhp just with 20" wheels on the back compared to the stocks.
I like how darren put in the "Double D" in the video:haha::haha::haha::haha:
The dyno numbers have not been fair for the stroker motors because of the limited air flow.
I'm glad they ran afterwards because this shows that a dyno is only a good reference for one car itself as oppose to comparing two cars.
The Classic BMW dyno here is a huge ego crusher. I currently am dynoing there for the sole purpose of keeping a controlled device for measuring mods. My car only dynoed 438rwhp will full bolt ons on the Classic BMW dyno but I believe in a dedicated dyno room I could see numbers at least at 480 on a dynojet.
The debate around dyno numbers are giving me more of a headache each day. Ultimately though, it's just nice to see what happens on the road where it matters.
like m5ranger, i too am confused... i understand that proper airflow for the dinan stroker will provide more power, but how come the numbers are so much lower than what had been documented with simple bolt-ons like rabdog's RPI setup? darren... did you guys not have a fan that could give 50mph+ airflow?
again i know numbers don't necessarily translate to real world results but they do give a relative performance picture.
the next obvious question is how much difference is there between RPI bolt-on's vs dinan stroker on the dyno in identical conditions? i recall watching kenny stare down darren's brake lights in a very dark video?
Not only did Kenny stare at his brake lights, he got walked pretty hard and it would have been the same result with RabDog's car. The point is...
Obviously the dyno tells only a small piece of the story. If you go by dyno performance here, same hp, same weight, 100+ lb. more tq to the Caddy, then Darren should have been anihilated. But it wasn't even close. It was an immediate run, not walk, away from the Caddy and once again the 997TT.
Great job, D! Way to rep for the stroker crew. I think Fubar might want a rematch in his other blown domestic vehicle. The outcome might be a little different! lol
It's great to see it perform where it matters, on the streets! Great job Darren:M5thumbs:
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