2008 Dinan Stroker M5 versus 2009 Cadillac CTS-V - Page 4

cshorter · 2nd March 2009, 13:44

What is the "approximate" price on the stroker upgrade?

darren_dallas · 2nd March 2009, 14:40

Quote:

Originally Posted by v8venom

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?

V8Venom,

They had a carpet fan on the oil cooler (it's basically a small shop fan meant for drying up water if there is leak in a house or building).

Basically what it boils down to is that you cannot paper race dynos, especially dynos from different locations/states even if they are the same manufacturer.

I did not run against Rab Dog, but I have run against Keang24 who has the same setup from RPI. Keang24 has run against Rab Dog many times and they even filmed some of the runs in December. Here is a video of Rab Dog and Keang24 going at it. Pay attention to Run #2 and the last run (45-165) and you'll see the cars are almost perfectly even each time:

+ YouTube Video

Given those results I suspect if Rab Dog and I run the results will be the same as the times I ran Keang24 here:

+ YouTube Video

Hope this helps.

Regards,

Darren

V12Godspeed · 2nd March 2009, 15:05

Nice Kill Darren. Your car is one of my favorite M's. Love the Dinan stroker kit!

Kelster · 2nd March 2009, 16:16

Quote:

Originally Posted by darren_dallas

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:

Quote:

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.

Ray

CASEY1 · 2nd March 2009, 16:19

I wonder what the total cost of the M5 is. Can buy new CTS-V's for 60k. Many mods are available for it already.

darren_dallas · 2nd March 2009, 16:33

Quote:

Originally Posted by Kelster

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:
Ray

Ray,

I understand what you're saying. It really boils down to simple math:

CTS-V rwhp on Saturday = 456 rwhp
CTS-V advertised crank hp = 556

If you do the math it works out to roughly 18% drivetrain loss, which is in-line for an automatic transmission.

So in this case I believe the numbers make sense are accurate for the CTS-V.

Hope this helps.

Cheers,

Darren

Qship5 · 2nd March 2009, 16:35

Nice run Darren! I'm sure Fubar will be looking for a rematch soon. At least once he dumps a few $ into mods. The V is no slouch in stock form and I would venture to say that with less than $10K in mods will be putting down more power than the stroker.

darren_dallas · 2nd March 2009, 16:35

Quote:

Originally Posted by CASEY1

I wonder what the total cost of the M5 is. Can buy new CTS-V's for 60k. Many mods are available for it already.

It's always been well known that you can mod most of the american cars much more economically than the european cars.

My friend in the CTS-V will no doubt slap on a pulley and an ecu tune and come back with a vengence and stand a good chance of beating me next time.

Leonie · 2nd March 2009, 16:36

I guess the price of the stroker kit (including labour) alone is about the same as a brand new CTS-V??

So I won´t say "great kill" but "obvious kill"...

Best, Bernd

Edit: I see you already made a reply yourself...

Tom C · 2nd March 2009, 16:39

Regardless of Darren's dyno results...I would rather have a car that performs in real world conditions than a "dyno queen". I think Darren's car has proven its mettle.

Tom