Dyno Shootout: Battle between Dinan and RD Sport for 4.6 Liter Stroker Motor Braggin

[Alekshop]

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Dyno Shootout: Battle between Dinan and RD Sport for 4.6 Liter Stroker Motor Bragging Rights

Introduction

From the time Dinan and RD Sport each introduced their 4.6L stroker motors, it's always been our dream to have a dyno shootout to see how they would match up against each other. Both companies make 4.6 liter stroker motors, but each took a slightly different approach in their design. Dinan chose to design a shorter stroke and bigger bore, while RD Sport chose to design a longer stroke and slightly smaller bore. The shorter stroke approach gives the Dinan stroker a 4608 cc displacement, and the longer stroke approach gives RD Sport a 4619 cc displacement. Practically speaking, both engines are the same displacement, but in theory the longer stroke of the RD engine should give it a torque advantage. We always wanted to put this theory to the test, so we called up our buddy "Mr. Data Collector" who would set it up and collect all the data.

The Dinan stroker motor was purchased by Alekshop customer "Dray-M3." This car is well known to Alekshop dyno days and has been dyno'd on three previous occasions. Dray-M3 always wanted to dyno his car, but we wanted to wait until Alekshop customer "Sleeper" finished his RD Sport stroker so we could dyno them together and turn this into a mini stroker shootout. But scheduling this shootout wasn't as easy as it sounds. It seemed that everybody's schedules never meshed. After six months of trying, we finally found a one-week window of opportunity where everybody was available. Not wanting to pass up this golden opportunity, we set it up and made it happen.

The Dinan Stroker

The Dinan stroker comes in a complete turn-key package. If you don't want to send in your own motor in advance, Dinan will build up one of their cores and ship you the engine as soon as it's completed. They charge you a nominal core charge which is refunded as soon as your engine is received. To gain maximum power from the Dinan stroker, Dinan also recommends to purchase Dinan stage-2 intake, Dinan throttle bodies, 16% underdrive pulley, and free flow exhaust. Although these accessories cost extra, Dinan does list them as optional to achieve maximum power.


Price: $25,999, includes:

• Bore: 94mm / Stroke: 83mm (4608 cc displacement)
• Compression Ratio: 12.0:1
• Dinan proprietary billet crankshaft
• Dinan proprietary lightweight forged pistons
• Dinan proprietary light-weight connecting rods
• Balanced and blueprinted
• Dinan electronics and engine management software
• Dinan serial numbered block

Optional Equipment / Expenses:

• Exhaust
• Under drive pulley
• Stage-2 inake
• Throttle bodies
• Installation

Rated power output (measured at crankshaft):

• 502 horsepower @ 7500-7800 RPMs *
• 384 ft-lbs torque @ 5600 RPMs *
• 527 horsepower @ 7800 RPMs **
• 407 ft-lbs torque @ 5200 RPMs **

* Engine tested using 93 octane with High Flow Intake Stage 2, Throttle Bodies, 16% underdrive pulley and Free Flow Mufflers
** Engine tested same as (*) above, but with BOTH CAT delete, Dinan racing mid-pipe, and Dinan racing exhaust.

The Dinan crankshaft is a top quality piece. It's manufactured from billet steel at a highly reputable crankshaft manufacturer who specializes in these types of custom builds. Dinan uses Mahle pistons made to their specifications. The pistons are made from the same manufacturing line as the factory BMW pistons, thus guarantees their compatibility with the S65's Alusil engine block. Dinan seemed to skimp a little on the connecting rods. Though they are made by Carrillo, Dinan chose to use the Carrillo A-Beam connecting rods -- which are considered a "budget" connecting rod. The A-Beam is plenty strong for this application, but you wouldn't want to supercharge this engine with the A-Beam connecting rod. Since most people aren't "boosting" their stroker motors, the A-Beam rod should not dissuade anybody from buying this stroker motor.

I found only one nit against the Dinan stroker: it's the use of a 94mm bore. Old rule of thumb says you shouldn't bore more than 2mm over stock, lest the cylinder walls become too thin and you can't rebuild the engine beyond this point. The stock bore starts at 92mm, so boring to 94mm means you're at the limits of the cylinder walls and may not have any options except replacing the motor should you ever need to rebuild it. Dinan believes the extra bore size was important to meet their philosophy of making the engine as "square" as possible (getting the bore size equal to the stroke length). Many engine builders believe this too and are willing to make this trade off. Hopefully our dyno test will see how well this works.



The RD Sport Stroker

The RD Sport stroker also comes in a complete turn-key package. Just as with Dinan, if you don't want to send in your motor in advance, RD Sport will build one for you from one of their available cores. The RD Sport stroker comes in two flavors: 1) Basic Stroker, 2) Full Stroker Package. RD Sport also offers custom stroker packages using custom strokes (82mm - 85mm), custom bore sizes (up to 94mm,), low compression pistons for supercharged applications, and Carrillo H-Beam-HD connecting rods for supercharged stroker applications. RD Sport has built both high and low compression stroker motors from 4.4L to 4.7L displacements.


Price: $23,995 includes (Basic Stroker Package)

• Bore: 93mm / Stroker: 85mm (4619 cc displacement)
• Compression Ratio: 12.0:1
• RD Sport billet crankshaft
• Mahle lightweight forged pistons
• Carrillo H-Beam connecting rods
• Balanced and blueprinted
• 16% Underdrive pulley
• RD Sport engine management software

Price: $32,995 includes (Full Stroker Package)

• All of the above
• RD Sport proprietary long tube headers
• RD Sport high flow CATs
• RD Sport mid pipe
• RD Sport high flow exhaust

Optional Equipment / Expenses ***

• Front bumper which also serves more air to the intake system
• Installation

Rated power output (measured at crankshaft):

• 480 horsepower @ 7700 RPMs *
• 387 ft-lbs @ 4800 RPMs *
• 525 horsepower @ 7700 RPMs **
• 425 ft-lbs @ 4800 RPMs **

* Basic Stroker Package tested with 91 octane gasoline, stock exhaust
** Full Stroker Package tested with 96 octane gasoline
*** Installation is free when RD Sport has access to the car

The RD Sport crankshaft is also a top quality piece. Also made from billet steel, this crankshaft comes from an equally reputable crankshaft manufacturer who specializes in these types of custom builds. RD Sport uses Mahle pistons made to their specifications. The pistons are made from the same manufacturing line as the factory BMW pistons, thus guarantees their compatibility with the S65's Alusil engine block. Instead of using the Carrillo "budget" A-Beam connecting rod, RD Sport uses the stronger and ($500 more expensive) H-Beam connecting rod. But RD Sport also offers the Carrillo H-Beam-HD connecting rod for low compression supercharged stroker motors.

I also found one nit against the RD Stroker. If you live near RD Sport facilities, they will install your engine for free as part of the price. But if you don't live nearby or can't ship your car, there is no cash allowance or rebate for the installation. RD Sport explains that they offer the installation service as complimentary, but really isn't included as part of the price. Even without this allowance, sending the car to RD Sport is worth the extra money, because it's still cheaper to send the car on a round trip journey than it is to pay your local shop to perform the installation.



A Third Entry into the battle

We originally planned a head's up match between the two strokers. But after thinking about it, we decided to add a third car into the mix. The Alekshop M3 is a 2013 Limerock Edition that is being build as US Spec M3 GTS. As of today it still has a stock 4.0 Engine. But we thought it would be nice to add this car to the mix because it has enough bolt-on performance enhancers that might put it into the running.



Testing Methodology


Over the past few years, we've run many dyno days and tested approximately 40-50 BMW M3's. We test each car with the same methodology and as time goes on, we have developed the ability to data log many important parameters and incorporate them into our dyno charts. Today's methodology is as follows:

• Neither Dinan nor RD Sport were notified in advance of this test.
• Three or more dyno runs until the car doesn't make any more power.
• Use best three runs, regardless.
• Dyno each car in same gear (4th gear).
• Attempt to dyno each car at same engine temperatures.
• Heat soak test the car to see if it degrades performance. Runs are usually about 2-minutes apart. This induces a heat soak test to see how the car performs under stressful back to back conditions.
• Data Logging with BT Tool
  • RPM
  • Throttle Position
  • Gear Selection
  • Intake Air Temperature (IAT)
  • Spark Advance (can see knock)
  • Both O2 Sensors (converts to Air-Fuel-Ratio)
  • Oil Temperature
  • Water Temperature
• Data Logging with Kestrel Weather Station. This allows us to verify accuracy of Dyno weather station and the Dyno horsepower correction formulas. This prevents cheating.
  • Temperature
  • Barometric pressure
  • Humidity
  • Density Altitude
• Filming. All runs filmed without breaks from start to finish.

Prices as tested (MSRP prices, excluding installation):

Dinan price as tested: $35,496

• Dinan 4.6L Stroker Motor
• Dinan Throttle Bodies
• Dinan Underdrive Pulley
• Dinan Stage-2 Intake
• Akrapovic Evolution Exhaust

RD Sport price as tested: $29,995

• RD Sport 4.6L Stroker Motor
• RD Sport Underdrive Pulley
• Akrapovic Evolution Exhaust

Alekshop M3 price as tested: $$$ Don't even ask. $$$








Results
This is the part of the report we call the "Data Storm." We will present the data we collected, and let you be the judge of what it means. These results will certainly spark a controversy and a heated debate. At the very bottom, we will make some observations. We only ask that you post your opinions in a respectful manner.

Dyno Charts (SAE Correction):





Dyno Charts (STD Correction):



Dyno Charts (Uncorrected):



Does this really matter?
Out of our own curiosity, we decided to graph the engine data logs during the entire dyno session to see how the temperatures changed during the entire event.

Dinan



RD Sport



Alekshop M3




Post Mortem
To say the least, we were shocked by the results. The RD Sport handily beat the Dinan stroker, and the Alekshop M3 even beat the Dinan stroker. The extra torque of the RD Sport stroker is overwhelming and evident. The RD Stroker has a consistent torque advantage over the Dinan stroker from start to finish. But we were shocked that the Alekshop M3 beat the Dinan stroker. So we asked "Mr. Data Collector" to dig deeper into the results to see what he could discover the reasons.

It's our belief that there's a few things wrong with the Dinan tune. We can see from the data logs that the Dinan ECU starts closing the throttle bodies around 5500 RPMs and doesn't fully open them even to redline. This appears to be in response to some knock events because the throttle bodies begin to close around the same time we see spark retarding due to knock. Just to ensure the throttle bodies weren't closing due to dyno operator error, we looked at the data logs for all Dinan runs and we see the same exact closing for every run (see supporting data below).

The Dinan ECU is also very conservative on spark advance having a min of 8 degrees advance and max of 27 degress. Compared to the others, this seems far too conservative. Both the RD Sport and ESS ECU have minimum 15 degrees advance and maximum 34 degrees advance. The Dinan Stage-2 Intake also seems to retain or pass along more heat than the factory intake. Even though the ambient temperature was coldest during the Dinan dyno runs, the data logs show the Dinan intake air temperatures (IAT's) were significantly higher than the other two cars (see supporting details below).

After running this test, both Dinan and RD Sport were notified of the results. Both companies responded with the same comments: that's not our latest ECU files! I'm not sure it would have mattered because it appears the RD Stroker has a sizeable torque advantage, but it's unknown how much of this advantage is due to the different ECU tuning. As of this writing, the Dinan dyno files and data logs have been sent to the car's owner, who at the request of Dinan, will turn them over to Dinan for review. Following review, it is our belief that Dinan will retune the car. In the mean time, RD Sport has also shown an interest in retuning their customer's car. So it sounds like we have all the makings of a rematch. Stay tuned!

[Alekshop]

Car and Modifications:

• 2011 BMW M3
• Dinan 4.6L Stroker Motor
• Dinan Underdrive Pulley
• Dinan Stage-2 Intake
• Dinan Throttle Bodies
• Akrapovic Evolution Exhaust
• 91 Octane
• DCT

Conditions (Dynojet Weather Station):

• Temperature:: 68.55 degrees F
• Atmospheric pressure: 29.92 inHg
• Humidity: 41%
• Density Altitude: 787 Ft.
• SAE Correction: 0.975
• STD Correction: 1.002
• Uncorrected: 1.000

Results:

• SAE Corrected: 375whp @ 8110 RPM, 296wtq @ 3990 RPM
• STD Corrected: 386whp, 304wtq
• Uncorrected: 385whp, 304wtq

Dyno Database:

• Dyno files are available from the links below.
• SAE Corrected, STD Corrected, Uncorrected

Individual Dyno Results:

Individual dyno results are shown below. SAE corrected results are shown twice, using two different sources. The first source (djc) are the SAE corrected results straight from the Dynojet. The second source (sae) of SAE corrected results are obtained by using the Kestral 4500 weather station data for each individual dyno run and running it through an independent SAE correction formula. This ensures that the dyno results are accurate and can be independently audited and verified for authenticity and accuracy.

The legend below has the following meaning:

• Dyno Run: Dyno run file
• Timestamp
• Temp(F) = Temperature (Farenheit)
• RelH = Relative Humidity
• Pressure(Hg) = Barometric Pressure
• DA(ft) = Density Altitude
• IAT = Intake Air Temperature
• Oil(F) = Oil Temperature (Farenheit)
• O2(F) = Water Temperature (Farenheit)
• WHP(unc) = Uncorrected wheel horsepower
• WTQ(unc) = Uncorrected wheel torque
• WHP(SAEd) = Dynojet SAE corrected wheel horsepower (SAE-1340 PRE-2004)
• WTQ(SAEd) = Dynojet corrected wheel torque (SAE-1349 PRE-2004)
• WHP(SAEk) = SAE-Adapted wheel horsepower (SAE-1349 2004+)
• WTQ(SAEk) = SAE-Adapted wheel torque (SAE-1349 2004+)

* Entry used for the Dyno Database

Graphs:
SAE Correction:


Comparison with Baseline:



STD Correction:


Uncorrected:



Engine Vital Statistics:


Comparison for all runs:

[Alekshop]

RD Sport Stroker Motor



Car and Modifications:

• 2009 BMW M3
• RD Sport 4.6L Stroker Motor
• RD Sport Underdrive Pulley
• Akrapovic Evolution Exhaust
• 91 Octane
• DCT

Conditions (Dynojet Weather Station):

• Temperature:: 70.50 degrees F
• Atmospheric pressure: 29.93 inHg
• Humidity: 39%
• Density Altitude: 903 Ft.
• SAE Correction: 0.977
• STD Correction: 1.004
• Uncorrected: 1.000

Results:

• SAE Corrected: 390whp @ 7700 RPM, 316wtq @ 3860 RPM
• STD Corrected: 400whp, 325wtq
• Uncorrected: 399whp, 324wtq

Dyno Database:

• Dyno files are available from the links below.
• SAE Corrected, STD Corrected, Uncorrected

Individual Dyno Results:

Individual dyno results are shown below. SAE corrected results are shown twice, using two different sources. The first source (djc) are the SAE corrected results straight from the Dynojet. The second source (sae) of SAE corrected results are obtained by using the Kestral 4500 weather station data for each individual dyno run and running it through an independent SAE correction formula. This ensures that the dyno results are accurate and can be independently audited and verified for authenticity and accuracy.

The legend below has the following meaning:

• Dyno Run: Dyno run file
• Timestamp
• Temp(F) = Temperature (Farenheit)
• RelH = Relative Humidity
• Pressure(Hg) = Barometric Pressure
• DA(ft) = Density Altitude
• IAT = Intake Air Temperature
• Oil(F) = Oil Temperature (Farenheit)
• O2(F) = Water Temperature (Farenheit)
• WHP(unc) = Uncorrected wheel horsepower
• WTQ(unc) = Uncorrected wheel torque
• WHP(SAEd) = Dynojet SAE corrected wheel horsepower (SAE-1340 PRE-2004)
• WTQ(SAEd) = Dynojet corrected wheel torque (SAE-1349 PRE-2004)
• WHP(SAEk) = SAE-Adapted wheel horsepower (SAE-1349 2004+)
• WTQ(SAEk) = SAE-Adapted wheel torque (SAE-1349 2004+)

* Entry used for the Dyno Database

Graphs:
SAE Correction:


Comparison with Baseline:



STD Correction:


Uncorrected:



Engine Vital Statistics:


Comparison for all runs:

[Alekshop]

Alekshop M3



Car and Modifications:

• 2013 BMW M3, Limerock Edition
• Akrapovic GT4 Exhaust
• Both CAT Delete
• ESS ECU Tune
• 91 Octane
• DCT

Conditions (Dynojet Weather Station):

• Temperature:: 72.45 degrees F
• Atmospheric pressure: 29.93 inHg
• Humidity: 36%
• Density Altitude: 1065 Ft.
• SAE Correction: 0.979
• STD Correction: 1.006
• Uncorrected: 1.000

Results:

• SAE Corrected: 379whp @ 8320 RPM, 272wtq @ 4040 RPM
• STD Corrected: 389whp, 279wtq
• Uncorrected: 387whp, 277wtq

Dyno Database:

• Dyno files are available from the links below.
• SAE Corrected, STD Corrected, Uncorrected

Individual Dyno Results:

Individual dyno results are shown below. SAE corrected results are shown twice, using two different sources. The first source (djc) are the SAE corrected results straight from the Dynojet. The second source (sae) of SAE corrected results are obtained by using the Kestral 4500 weather station data for each individual dyno run and running it through an independent SAE correction formula. This ensures that the dyno results are accurate and can be independently audited and verified for authenticity and accuracy.


The legend below has the following meaning:

• Dyno Run: Dyno run file
• Timestamp
• Temp(F) = Temperature (Farenheit)
• RelH = Relative Humidity
• Pressure(Hg) = Barometric Pressure
• DA(ft) = Density Altitude
• IAT = Intake Air Temperature
• Oil(F) = Oil Temperature (Farenheit)
• O2(F) = Water Temperature (Farenheit)
• WHP(unc) = Uncorrected wheel horsepower
• WTQ(unc) = Uncorrected wheel torque
• WHP(SAEd) = Dynojet SAE corrected wheel horsepower (SAE-1340 PRE-2004)
• WTQ(SAEd) = Dynojet corrected wheel torque (SAE-1349 PRE-2004)
• WHP(SAEk) = SAE-Adapted wheel horsepower (SAE-1349 2004+)
• WTQ(SAEk) = SAE-Adapted wheel torque (SAE-1349 2004+)

* Entry used for the Dyno Database

Graphs:
SAE Correction:



STD Correction:


Uncorrected:



Engine Vital Statistics:


Comparison for all runs:

[swhat]

Awesome but kinda sucks that your only getting an extra 20-30hp with a stroker kit wick cost 30k. I was hoping that the strokers would put out 450+hp.

[kiln]

My thoughts after reading this article. Buy a ESS tune and exhaust for the stock 4.0L and save yourself 30k.

[SYZ]

Great job documenting the monumental waste of money stroker kits are.

[Alekshop]

Stroker motors are great! Just requires a proper tune!

[Soorena]

Great thread. Thanks for sharing.

Originally Posted by kiln

My thoughts after reading this article. Buy a ESS tune and exhaust for the stock 4.0L and save yourself 30k.

The strokers need head work in order to show what the extra displacement can di. Notice how both Dinan and RDSport cars make peak HP at under ~7500 RPM? They need more air to keep making power like the OEM displacement car. Adding cams would boost up the HP curve at up top.

[kiln]

Originally Posted by Alekshop

Stroker motors are great! Just requires a proper tune!

Ok.... so.... Clients are shelling out 30K for these stroker engines and are not even receiving a proper tune? Figured a 'proper' tune would already come with the package.

[kiln]

Originally Posted by Soorena

Great thread. Thanks for sharing.

The strokers need head work in order to show what the extra displacement can di. Notice how both Dinan and RDSport cars make peak HP at under ~7500 RPM? They need more air to keep making power like the OEM displacement car. Adding cams would boost up the HP curve at up top.

You are correct.. but this thread is about this particular setup...and not what it could be...

Would definitely like to see a cylinder head flowing more CFM when increasing displacement.

[IMG]

Good thing cause i was planing on getting a stroker + Ess kit !
Good work Aleks !

[IMG]

Originally Posted by Team Plutonium

[slicer]

One of the most informative posts on the forum. Thank you for performing the test, gathering the data, and posting!

[Jbook]

Thanks for posting! It really was amazing seeing all three of these cars on the dyno in person. Aleks' Akra GT4 sounded amazing!! The strokers sounded so deep and aggressive, but I was suprised to see the dyno results as were the owners.

[GOLFFRR]

wow awesome info. great detail.

[BMRLVR]

Great post! I am going to be doing a stroker eventually, but I think I am going to retain the stock 92MM bore so that I will end up with a 4.4L stroker.

To be honest, I am not as much interested in the power and torque increase as I am interested in building the bottom end and adjusting the main and rod bearing clearances to something that I feel is more reasonable than BMW's 0.001" factory set clearance......... I intend in keeping my E90 indefinitely so I want the engine to stay together.

[BuckRodgers]

Good info thanks for posting. Strokers are way overpriced if you are looking for power. You can buy an ESS VT1-550 and make more power for 20k less. If you want a NA M3 and have the $$ they are a very cool option for these motors IMO.

[Richbot]

Are the cams changed in these kits? I have to wonder if they are not cammed aggressively enough above 6000 or so, these looks a lot like a head/cam setup on an early LS motor where the owner chooses big-flowing heads with a fairly mild cam for streetability. Big gains in the midrange but the slope of the curve tails off in the higher rpm. With VANOS a big cam's streetability seems less problematic? Looks like untapped potential to me, but I'm sure development would be off-the-charts expensive, and 8000+rpm means a bigger cam would probably need a revamped valvetrain to keep the weight down

Makes the S85 swap look kinda like an awesome idea...kinda

[flipm3]

Oh man....MIND BLOWN.....I love the data.

I'm going to have to study this before making a comment.

Before I make any long post and analysis, the difference in ignition and AFR targets amongst the three cars are rather interesting to note.

Awesome post Aleks! Can't wait to take a closer look to all of this

[IMG]

Originally Posted by Richbot

Are the cams changed in these kits? I have to wonder if they are not cammed aggressively enough above 6000 or so, these looks a lot like a head/cam setup on an early LS motor
where the owner chooses big-flowing heads with a fairly mild cam for streetability. Big gains in the midrange but the slope of the curve tails off in the higher rpm. With VANOS a big cam's
streetability seems less problematic? Looks like untapped potential to me, but I'm sure development would be off-the-charts expensive, and 8000+rpm means a bigger cam would probably need a
revamped valvetrain to keep the weight down.

Both companies offer upgraded cams, but neither of these motors had them installed. Both companies include upgraded valve springs with their strokers as part of the build.

[dtmwerksm3]

Originally Posted by SYZ

Great job documenting the monumental waste of money stroker kits are.

Agreed, why anyone would shell out 30k+ for an extra 20-30hp is beyond me, unless they like flushing money down the toilet. Get some Turner Test Pipes and a ESS Tune and you're already beyond the output of a stroker, throw a ESS supercharger in the mix and you're still at half the cost and twice the output.

Stroker Kits