S54 Dyno Database

[paulclaude]

i find the single larger roller to be more consistent due to the huge variables associated with the tyre interface being more controllable. Both Maha and DJ use a single roller. DD, mustang, DC, mainline use a twin roller although some brands have both twin and single rollers depending on model. i also have a theory that a 2WD dyno reads a bit more than a 4WD in 2WD mode.

Many years ago i tested within a couple days a DD, DJ and Maha (couldnt get a booking with a Mainline) on an old shit box ill see if i can dig out the results. DD i find inconsistent really need to stick to 1 dyno and operator on those.

Agree that a single roller system has it's benefits, however I think the consistency of the readout comes down to the setup of the dyno, how well balanced and aligned the rollers are etc. From what i've been told, the balancing and alignment of some roller sets can be poorly set from the factory, even from reputable dyno brands. My own is a 4-roller set, and I've had it all realigned and rollers balanced, and it's super consistent, usually within a couple of HP each pull.

I've used both the later digital type DD and earlier analogue (DOS based) systems, and definitely agree that the later digital controllers are nowhere near as repeatable as the older type.

[DESMDR3]

Nice, seems like solid numbers for those mods! Was the B-spec an OTS tune or custom? Thanx for posting up!

OTS tune. It’s been good, the car feels strong. I haven’t experienced any issues with drivability. When I get some more mods, I will definitely be going custom 👍🏼

[digger]

I think I’m following...so, his car made 378BHP, and 294WHP...based on a 22% driveline loss vs. the more normally accepted 14-15%—correct? So, if we extrapolate, and figure the WHP based on say 14%, his actual WHP would be closer to 325? That seems a bit low to me (for the mods) vs. what I’m used to seeing. Typically, cars w/cams air boxes & supporting mods are in the 340-350WHP SAE on a Dynojet.

the dyno is measuring the wheel hp and adding a correction, you cant say the bhp is correct and say the the losses should be 15% and therfore the whp is more like 325 thats kinda backwards. the rwhp should be the same sans assumption on inertia of machine plus vehicle drivettrain and physical losses due to different roller geometry and different CF standard..

the DJ losses are at most 15% often 13% at peak hp and more like 10% at peak torque assuming BMW RWD, MT. if you look at healthy examples of BMWs from the good ol days (no turbo nonsense) thats what i always came up with.

the issue is alot of the time peoples first stock baselines are rubbish so the delta is also rubbish obviously doesnt explain why some see 70whp gain and others 1/3rd of that

[digger]

Digger,

I always see them in the range of 272-282 at max put on pump 91 gas.

Again small variations may vary in the the settings which contribute what you are seen
or experienced.



Correct, exactly what I have calculated in previous post. 378crank HP or (BHP UK)
minus 22% which is Exact what this dyno calculates the losses in %

Dyno-Jet per my personal experience have done quite few test is about 14%
I never believed those who will put losses in 17%range..

There is also another very important factor that plays roll in the dyno testings.

- How low the car is, suspension changes can create losses, toe, axle changes due to
being lowered etc.
- After market wheels with much wider tires will also be considered as drag factor which
All of this will reflect the end of the hp number.

Regards,
Anri

i find the single larger roller to be more consistent due to the huge variables associated with the tyre interface being more controllable. Both Maha and DJ use a single roller. DD, mustang, DC, mainline use a twin roller although some brands have both twin and single rollers depending on model. i also have a theory that a 2WD dyno reads a bit more than a 4WD in 2WD mode.

Many years ago i tested within a couple days a DD, DJ and Maha (couldnt get a booking with a Mainline) on an old shit box ill see if i can dig out the results. DD i find inconsistent really need to stick to 1 dyno and operator on those.

[stash1]

Lets not start another dyno vs. dyno numbers debate - too many variables to compare from one to another. Numbers differ, dynos differ, they all have their positives and negatives. I personally prefer a braked dyno that can control ramp time to simulate actual road acceleration vs. a large inertial roller as per DJ which can't be controlled (on most DJ, anyway) - then you end up with acceleration times of the power run that differ from real world conditions. That load/acceleration difference can lead to inaccuracies in the tune when the car hits the road or track, especially for turbo/boosted setups. As for the coast down debate - it's exactly that, negative losses on coast down from ending RPM which is added to the curve to calculate for flywheel. How the dyno uses those measured losses can differ, but either way it's the most accurate way to determine transmission loss vs. a fixed correction factor.

Anyway, here's one from my own Dyno, on my own track car.

-Supercharged @ 10psi boost
-Schrick 288/280
-Euro Headers
-2.5" Dual Section 1, 2 - decat
-SS LWR rear silencer
-Shite local fuel
-AEM Infinity Standalone

575HP / 379lb/ft TQ

Nope, we’re def not going there! ...and nice Paul! Looks like a strong runner!

[stash1]

Stan,

My Man, you keep confusing based on what you are used to see on Dyno-Jet.

Again, follow the logic here, UK will rate BHP crank HP much lower than BMW
AG advertised the S54 at 343 DIN HP Crank.

In this exact case, you do have the saying.... "Dyno is a tool to see the improvements from the parts being installed"
aka Before and After. So if Martyn's S54 base run is 200rwhp and after tune box etc makes 230rwhp
you have 30hp gain over the base run and that's it don't keep looking for logic to compare to DJ

Accept the European Dyno services again as tool for "Before and After"..don't try to search for logic of
what you and I are used to see.

Like I mentioned before never been fan of this hp presentation. I am also pretty much sure that Dyno-Jet
will have much stable weather factor calibration, I have seen the Dyno-Jet too change from different days
from 14% down to 13%. So very little % in weather factor changes.


Regards,
Anri

Ahhh sh*t balls then, thought I was really on to something. Sooo, there is absolutely no way to make any type of comparison between EU BHP numbers and a Dynojet—got it! I thought that you were just saying that the driveline % calc was off...but it just doesn’t flush.

[stash1]

Lol don't worry about it dude. Trust me, I was expecting bigger gains with the airbox but no amount of vanos work could bring it any higher! Still a ~50bhp jump over stock isn't anything to sniff at.

Perhaps we need to start a 100-200kph time thread for those with VBOXs / Draggy etc.

Cool, yeah, 50 HP over stock is def noticeable in the seat of your britches! Ya, actual acceleration numbers would be a better metric to go by...providing traction isn’t a factor.

[paulclaude]

Lets not start another dyno vs. dyno numbers debate - too many variables to compare from one to another. Numbers differ, dynos differ, they all have their positives and negatives. I personally prefer a braked dyno that can control ramp time to simulate actual road acceleration vs. a large inertial roller as per DJ which can't be controlled (on most DJ, anyway) - then you end up with acceleration times of the power run that differ from real world conditions. That load/acceleration difference can lead to inaccuracies in the tune when the car hits the road or track, especially for turbo/boosted setups. As for the coast down debate - it's exactly that, negative losses on coast down from ending RPM which is added to the curve to calculate for flywheel. How the dyno uses those measured losses can differ, but either way it's the most accurate way to determine transmission loss vs. a fixed correction factor.

Anyway, here's one from my own Dyno, on my own track car.

-Supercharged @ 10psi boost
-Schrick 288/280
-Euro Headers
-2.5" Dual Section 1, 2 - decat
-SS LWR rear silencer
-Shite local fuel
-AEM Infinity Standalone

575HP / 379lb/ft TQ

[Anri]

I’ve often wondered how suspension set up might impact dyno numbers as well. Would be interesting to actually be able to test for that stuff!

Stan,

Logic again, We assume BMW knows what they are doing. Those Engineers designed the suspension
dynamics and the Axle, Differential position, Camber and Toe around the STD right hight as how BMW E46M3
was sold off your local authorized BMW dealer back in 2001.

Think about what is happening with your car when its dropped. I assume your M3 is lowered
by at least 1.5" inches from std right hight ?

Use logic how the Axle do work. The more you change them in the Wrong degree the more load you
are applying to the bearings. Differential clutches do get load as well. The Axle outer and inner bearings
do receive drag/loads when not as horizontal as possible under loads. Tow plays big roll into all of this,
set the toe-in at 0.17-0.20, camber at low -1.5 and you will note difference on the track at your trap speed,
most likely not visible on the street but with track data you will see few mph less.

Now, how much HP/drag all of this will filter coming from your cammed engine the only way to find out is
spent time for testing. The losses may be very very micro down to none I have no data but I know for a fact
that Axels do not work well when they are not as horizontal as possible under load.

Regards,
Anri

[Anri]

I think I’m following...so, his car made 378BHP, and 294WHP...based on a 22% driveline loss vs. the more normally accepted 14-15%—correct? So, if we extrapolate, and figure the WHP based on say 14%, his actual WHP would be closer to 325? That seems a bit low to me (for the mods) vs. what I’m used to seeing. Typically, cars w/cams air boxes & supporting mods are in the 340-350WHP SAE on a Dynojet.

Stan,

My Man, you keep confusing based on what you are used to see on Dyno-Jet.

Again, follow the logic here, UK will rate BHP crank HP much lower than BMW
AG advertised the S54 at 343 DIN HP Crank.

In this exact case, you do have the saying.... "Dyno is a tool to see the improvements from the parts being installed"
aka Before and After. So if Martyn's S54 base run is 200rwhp and after tune box etc makes 230rwhp
you have 30hp gain over the base run and that's it don't keep looking for logic to compare to DJ

Accept the European Dyno services again as tool for "Before and After"..don't try to search for logic of
what you and I are used to see.

Like I mentioned before never been fan of this hp presentation. I am also pretty much sure that Dyno-Jet
will have much stable weather factor calibration, I have seen the Dyno-Jet too change from different days
from 14% down to 13%. So very little % in weather factor changes.


Regards,
Anri

[Martyn]

Sorry Martyn, don’t want it to seem like we’re speaking about you while you’re standing in the room-lol. Think we’re just puzzled by the delta.

Lol don't worry about it dude. Trust me, I was expecting bigger gains with the airbox but no amount of vanos work could bring it any higher! Still a ~50bhp jump over stock isn't anything to sniff at.

Perhaps we need to start a 100-200kph time thread for those with VBOXs / Draggy etc.

[stash1]

Digger,

I always see them in the range of 272-282 at max put on pump 91 gas.

Again small variations may vary in the the settings which contribute what you are seen
or experienced.



Correct, exactly what I have calculated in previous post. 378crank HP or (BHP UK)
minus 22% which is Exact what this dyno calculates the losses in %

Dyno-Jet per my personal experience have done quite few test is about 14%
I never believed those who will put losses in 17%range..

There is also another very important factor that plays roll in the dyno testings.

- How low the car is, suspension changes can create losses, toe, axle changes due to
being lowered etc.
- After market wheels with much wider tires will also be considered as drag factor which
All of this will reflect the end of the hp number.

Regards,
Anri

Yep, agreed on the % loss, and I would like to think that I’m pretty well versed on most things dyno related...but there’s always room to learn! I’ve just always been fascinated by it-lol. I’ve often wondered how suspension set up might impact dyno numbers as well. Would be interesting to actually be able to test for that stuff!

[stash1]

it baselined at 281whp which is a bit higher than stock but its a euro car, has the eventuri which eliminates the bulk of the losses from the induction system and it has a aftermarket ECU so its a straight forward thing to tune fuel PW and timing, ignition timing, vanos etc.

A stock M3 makes 285 ish on a DJ if its running right which would probably be slightly more than that if it was low mileage to so not much inconsistent there.

The elephant in the room is cams and airbox netted like ~15-20 numbers maybe, its a bit hard to tell as the corrections are only applied to the flywheel numbers and the rotating mass changed from 50-70kg but that’s a lot less than what many would have you believe even accounting for the eventuri

Yeah, think I’m following what’s going on now, and yeah...I’ve seen stock DJ numbers from high 260’s to mid 280’s on stock cars...depending on mileage, state of tune, etc. Yep, the delta struck me as odd too. I’m kind of used to seeing gains of 20-35 HP for cams/airbox—weird. Sorry Martyn, don’t want it to seem like we’re speaking about you while you’re standing in the room-lol. Think we’re just puzzled by the delta.

[stash1]

Very first dyno so no baseline. APE flex fuel kit, B-Spec tune, catless headers. Ethanol blend @ E53

Nice, seems like solid numbers for those mods! Was the B-spec an OTS tune or custom? Thanx for posting up!

[stash1]

Stan,

Read the Dyno with cams and box etc.

Do the math and you will see how much the dyno calculation will never make sense to you.

Rear wheel 294rwhp. Crank says 378 BHP (crank HP). So, 378-22%= 294rwhp.

Hope this will make more sense to you ?

Regards,
Anri.

I think I’m following...so, his car made 378BHP, and 294WHP...based on a 22% driveline loss vs. the more normally accepted 14-15%—correct? So, if we extrapolate, and figure the WHP based on say 14%, his actual WHP would be closer to 325? That seems a bit low to me (for the mods) vs. what I’m used to seeing. Typically, cars w/cams air boxes & supporting mods are in the 340-350WHP SAE on a Dynojet.