Rpi scoop and afe intake..
- Thread starter Woots
- Start date
aerobod said:
Thanks for your input.
I appreciate the points that you've made. I've always made it clear that I make no claim to the absolute accuracy of dyno results produced by the DashDyno, because, as you say the only way to get such accurate figures is to remove the engine from the car. Then again, I wouldn't be measuring in "real-world" driving conditions in that scenario. As far as I'm concerned, there is no other way that I would be able to test and monitor changes in my experimentation with air-intake and exhaust mods without the use of a DashDyno or other similar datalogger connected to the car's ECU via the OBD II socket. Sometimes a tape measure is adequate, whilst other times a micrometer is required, and I think for my purpose, the DashDyno is a good enough tool for the job. It's certainly a better tool than mine, or anyone else's, butt dyno. :wink:
JuniorJet said:Stuart Truman said:Possibly the most technical :hijacked: ever...
Too bloody right, here's me;
"Oh I wonder what is going on in this popular thread....*click*.... WHHHAAAAAAAARRRTTT???????????" :dizzy:
Yes, isn't it amazing! A technical thread on performance on a popular car forum.
Can you just datalog time, distance and RPM with the DashDyno and output that as raw data? That would be useful to apply different equations and scenarios to, together with the environmental conditions and tyre size and model at the time of test.exdos said:
Does it give the capability to input tyre parameters such as variation in rolling radius with acceleration g-force (leading to squat), tyre type and tread depth? This parameter can actually change the effective gearing quite a bit, compared with just inputting the tyre size. Even a worn (but legal) tyre can be 2% different in rolling radius than a new one, in the case of the Z4M leading to a 7bhp over estimate of the engine power.
It would be great if you could provide some comparative raw data, it would be interesting to see how some of the basic modelling I've done on the Z4M in the past would compare with the DashDyno modelling.
Keep up the good work!
aerobod said:
With the DashDyno you can run it in "datalogger mode" or "dyno mode", where in datalogger mode you record any of the PIDs that the ECU will yield as raw data, or in dyno mode, you need to use a vehicle profile for dyno runs or acceleration timings.. I'll have a look for you tomorrow if it's possible to produce the specific data you suggest.
With regard to the PIDs that can be recorded: different vehicles will yield a different selection, and the Z4MC yields lots more than my Z3MC does. The Z4MC actually yields Air/Fuel ratios, which I've found useful. With regard to tyre diameter: I do account for tyre wear in my vehicle specific profiles to keep the data as accurate as possible. There's no facility for recording g-force.
Until this thread, I've never previously used BMEP as a measure of changes in engine performance because it uses the derived figure of torque from the dyno facility. Instead, I've used Volumetric Efficiency which I compute from the raw data using the PIDs of Engine RPM, Intake Air Temperature (IAT) and airflow through the MAF. I've made a template in Excel, which will compute a "rolling VE" which can be plotted on a graph against the other PIDs on a timeline. I've found this to be an invaluable help in understanding how the air-intake actually works and how modding the intake and exhaust affects the VE.
If you send a PM with your email, I'll send you a sample of raw data for you to look at and play with. likewise, I'd be very interested to learn what you've been doing.
Aerobod, thanks for your PM, I've sent you some data for you to play with. Enjoy! 8)
I know that many people are sceptical of the improvements that can be achieved with a ram air-intake (and I'm not referring to a metal pipe with a cone filter stuck on the end, but that's probably what most others are thinking of????), but when I've done the calculations, as shown in this thread, it's clear that all my figures tie up with each other. I've already shown the BMEP figures for a turbo-charged BMW engine, so I thought I'd find some information for a supercharger for the S54 engine.
Here's a link to the Active Autowerke Supercharger kit : http://store.activeautowerke.com/ac...eneration-7-supercharger-kit-level-2-p44.aspx This produces a Maximum Torque of 395 ft/lbs @ 5400rpm. Using the agreed BMEP formula, this gives a figure of 395psi or 28.24Bar,
So, although my ram intake mods produce very good improvements above OEM, the BMEP calculations show that these improvements are realistic (from 15.14Bar to 16.2Bar) by comparison to the BMEP figure for Turbo charging (22.1Bar) and Supercharging (28.24Bar). What I find particularly interesting though, is how maintaining torque throughout the rev range has a considerable effect on HP.
I know that many people are sceptical of the improvements that can be achieved with a ram air-intake (and I'm not referring to a metal pipe with a cone filter stuck on the end, but that's probably what most others are thinking of????), but when I've done the calculations, as shown in this thread, it's clear that all my figures tie up with each other. I've already shown the BMEP figures for a turbo-charged BMW engine, so I thought I'd find some information for a supercharger for the S54 engine.
Here's a link to the Active Autowerke Supercharger kit : http://store.activeautowerke.com/ac...eneration-7-supercharger-kit-level-2-p44.aspx This produces a Maximum Torque of 395 ft/lbs @ 5400rpm. Using the agreed BMEP formula, this gives a figure of 395psi or 28.24Bar,
So, although my ram intake mods produce very good improvements above OEM, the BMEP calculations show that these improvements are realistic (from 15.14Bar to 16.2Bar) by comparison to the BMEP figure for Turbo charging (22.1Bar) and Supercharging (28.24Bar). What I find particularly interesting though, is how maintaining torque throughout the rev range has a considerable effect on HP.
Liverpool
I've been reading these posts, but not contributing because I got lost very early.
However, if you do produce repeatable results of 20-50bhp increases, and start offering them to forum members, then I'll happily put one through some extended testing for you
However, if you do produce repeatable results of 20-50bhp increases, and start offering them to forum members, then I'll happily put one through some extended testing for you
Bing said:This is all great stuff, and I can feel a PowerPoint presentation coming on to aid our sales effort Exdos... You are going to have to spend some time explaining it to me in words of one syllable though - right now I am understanding one word in 3
Bing, You're doing quite well if you're already achieving 33.33% success rate with your understanding of this subject. You need to get the Mrs and Wee Bing to give you CPR and blow up your nose (i.e. ram effect) to get more oxygen to your brain. I reckon this way it's theoretically possible to get that figure up to 100%, dependent upon the starting point of your OEM IQ and how much time you've spent in Bars. :wink:
mmm-five said:I've been reading these posts, but not contributing because I got lost very early.
However, if you do produce repeatable results of 20-50bhp increases, and start offering them to forum members, then I'll happily put one through some extended testing for you
I'm currently waiting on a professionally made part, and once that's fitted, I'll know where I stand on this because I'll be able to compare that with my "Blue Peter" style ramcharger which produced the results in the graph. I may well ask you to help.
Bing said:This is all great stuff, and I can feel a PowerPoint presentation coming on to aid our sales effort Exdos... You are going to have to spend some time explaining it to me in words of one syllable though - right now I am understanding one word in 3
In large crayon font. I've made a few of those
Possibly a video to pad out the timing a bit. As a mentor once said, "PowerPoint; Made by people with no power who cannot make a point"
Sorry for the delay in replying – rather a busy weekend ... 
I’d still prefer a measured value for each car, but fair enough – pretty lucky given I just guessed at 15% when I used it before ...
I stand corrected.
Well if you will be paying me a suitable proportion of the profits from your invention, then yes, I’d be happy to consider funding the costs of the tests ...
OK, but this is really the crux of my challenge: you are showing a performance characteristic that can only be measured by the measuring system you are using, and cannot therefore, be confirmed by other, more widely used and, therefore, understood methods.
The scientist in me has to ask, “Is it a real characteristic, or is it an artefact of the measurement system?”
My apologies, I didn’t realise you wanted to exclude the “artefact” data above 7000-ish RPM; I was still looking at the complete graph which shows peak torque and peak power at 7800, hence wondering why you’d suddenly moved to 5400 rpm.
That is a very fair point and you certainly should not divulge anything that would put any future patent at risk.
Just because that is how power is calculated doesn’t make that gain any less extraordinary – torque at revs is power and getting power is what every racing driver (and petrol head) wants. One way of looking at it is the area under the torque curve (a very powerful measure) – if your numbers are right then the increase in that area must be (relatively) massive and it would be a huge advantage to any race car/team.
Regarding ram intake data - this is part of the challenge you face, as you say there is very little data about ram charger effects on road cars, and what there is seems to be generally dismissive of whether it is real at road car speeds and the associated air pressures. As I am generally rather conservative I will tend to be sceptical of claims that are a long way out of the norm.
However, that also means that I’m not the person to actually make those conceptual leaps; but I can assure I would be delighted if you were proved correct, and I’ll be at the front of the queue to buy one.
I shall happily contain any concerns and wait until you are in a position to share more information. Though I'm still open to the deal I suggested above ...
I don’t know how realistic it is to compare absolute BMEP values between forced induction and NA engines; certainly I’ve read comments that comparison between spark ignition and compression ignition values is not really possible, so the same may apply.
exdos said:
I’d still prefer a measured value for each car, but fair enough – pretty lucky given I just guessed at 15% when I used it before ...
exdos said:
I stand corrected.
exdos said:
Well if you will be paying me a suitable proportion of the profits from your invention, then yes, I’d be happy to consider funding the costs of the tests ...
exdos said:
OK, but this is really the crux of my challenge: you are showing a performance characteristic that can only be measured by the measuring system you are using, and cannot therefore, be confirmed by other, more widely used and, therefore, understood methods.
The scientist in me has to ask, “Is it a real characteristic, or is it an artefact of the measurement system?”
exdos said:
My apologies, I didn’t realise you wanted to exclude the “artefact” data above 7000-ish RPM; I was still looking at the complete graph which shows peak torque and peak power at 7800, hence wondering why you’d suddenly moved to 5400 rpm.
exdos said:
That is a very fair point and you certainly should not divulge anything that would put any future patent at risk.
exdos said:I’ve explained previously how the spike in torque occurred in my ramcharger run, and the HP figure is solely a consequence of that. If you can find me any proper technical information about ram-intakes with lots of published data, I’d be obliged if you’d refer me to it. As it is, I consider that I'm in "unknown territory" but if you have better information to guide me, it would be most helpful.tertius said:
Just because that is how power is calculated doesn’t make that gain any less extraordinary – torque at revs is power and getting power is what every racing driver (and petrol head) wants. One way of looking at it is the area under the torque curve (a very powerful measure) – if your numbers are right then the increase in that area must be (relatively) massive and it would be a huge advantage to any race car/team.
Regarding ram intake data - this is part of the challenge you face, as you say there is very little data about ram charger effects on road cars, and what there is seems to be generally dismissive of whether it is real at road car speeds and the associated air pressures. As I am generally rather conservative I will tend to be sceptical of claims that are a long way out of the norm.
However, that also means that I’m not the person to actually make those conceptual leaps; but I can assure I would be delighted if you were proved correct, and I’ll be at the front of the queue to buy one.
I shall happily contain any concerns and wait until you are in a position to share more information. Though I'm still open to the deal I suggested above ...
exdos said:
I don’t know how realistic it is to compare absolute BMEP values between forced induction and NA engines; certainly I’ve read comments that comparison between spark ignition and compression ignition values is not really possible, so the same may apply.
No worries.tertius said:Sorry for the delay in replying – rather a busy weekend ...
There are quite a number of different commercially available ECU dataloggers and software for laptops which connect to the OBDII socket and which do dyno runs in the same way that the DashDyno does; such as Dash Hawk, DashDaq, Scangauge. These things have been around for a number of years now. My car will show the same results with any of these devices (with the proviso that they use the same formulae to compute torque /HP) because they also use the data yielded by the car’s ECU.tertius said:
With specific regard to what I have described as an “artefact” which shows a “blip" in the torque plot; this is not actually an artefact in the calculation of torque at that point on the rev range. What I am trying to express is that I didn’t maintain my foot to the floor to achieve WOT up to the redline, therefore the plot of torque that you see, shows that when I slightly lifted –off, the ram pressure instantly increased within the air-intake system, so that when I re-applied WOT, the engine was ingesting a greater mass of air than it would’ve otherwise done had I maintained WOT throughout. The DashDyno has faithfully recorded what has happened and the scientist in me interprets the plot as showing that my air-intake can provide a little “boost” in such a situation because it really is harnessing the ram-effect.
Accepted. If I’d maintained WOT throughout that run, as I’ve described above, the peak torque would still only have occurred at 5400rpm. This wouldn't affect the BMEP at peak torque, but it has affected the HP figure, and I agree that this is probably recorded greater than it would have been had the car ben driven at WOT throughout the run, and that IS an artefact. Having said that, the HP figure would still be very high.tertius said:
I agree that the results do appear extraordinary, and it’s entirely due to this that I’ve been driven to investigate and develop my ideas, based entirely on my observations. Not only can I record and see these gains graphically, but I can also feel and see them when I’m driving my cars with my ramcharger mods. There is power available throughout the rev range and when you change up and accelerate there appears to be even more, because the engine revs have dropped and the ram pressure has increased.tertius said:
That’s the problem; there is scant data on this, so the only way I’ve been able to get any, is collect my own, and this is where my DashDyno has been so useful to me. From the outset, I’ve been aware of the generally dismissive attitude to the usefulness of the ram-effect, but if it’s good enough for F1 cars, and they don’t spend all their time at 200mph either.tertius said:
Surely the BMEP figure of the OEM S54 at 15.1 is comparable with the BMEP of the same engine with an Active Autowerke Supercharger kit which gives a figure of 28.24Bar? As we’ve calculated, my ramcharger increase the BMEP to just 16.2Bar, which is well short of that figure.tertius said:
exdos said:
Well, I'm not sure about that.
I mean you can obviously compare them but drawing conclusions may be difficult. If you look for example here you'll see the comment, "It is worthwhile to note that a contemporary, normally-aspirated CI (compression-ignition) engine can easily make 15 bar of BMEP, and several turbocharged CI street engines routinely exceed 20.5 bar. It is helpful to remember that BMEP is a useful tool for comparing and evaluating similar types of engines."
And since BMEP is giving a measure of how efficiently an engine produces torque from capacity and forced induction is sort of an artificial way of increasing capacity it makes sense that the values aren't readily comparable.
tertius said:
A compression-ignition (CI) engine is a Diesel, whereas the S54 engine is petrol spark-ignition (SI), so you'd be comparing apples with oranges there.
My reference to BMEP is to compare the same S54 engine (SI) running with: 1.) a ram-air intake at 16.2 Bar and then with 2.) a supercharger when it operates at 28.24 Bar. To me, that's comparing apples with apples because the engine is the same and the only difference is the amount of air that you can stuff in it with a supercharger, which increases torque, hence it will increase the BMEP.
exdos said:
Yes I understand that. That quote was not meant to be exhaustive, my point was that a supercharged engine is not really a similar type of engine as a normally aspirated one. Taking the examples from the quote above: the forced induction CI engines are producing BMEPs more than 30% better than the NA CI engines but I don't think we could conclude from that that the NA versions are poorly designed would we?
What I take from that is that there are really four classes, which really need to be compared within their categories:
1. Spark ignition normally aspirated
2. Spark ignition forced induction;
3. Compression ignition normally aspirated
4. Compression ignition forced induction;