Hi guys,

Most of you have no doubt seen my new Dyno cell in the build topic and now it's all up and running to my satisfaction I will on Monday be turning my attention specifically to installing a TMIC cooling solution. I have a couple of ideas in mind but it occurred to me tonight that a thousand heads are better than none and it was well worth asking you guys as you will certainly have been to more Scooby rolling road days than I have.

So, my three questions are:

1) do you have an image showing how yours or a friends was done on the Dyno.
2) Have you ever had problems with excessive ACT's on such Dyno runs.
3) Do you have a "wish list" for such items from a Dyno facility? (IE: I wish they would do xyz for my car)

All input would be very gratefully received before I spend my money this week and then later spot a far better solution I could have considered.

A link to my cell as it stands today.
http://www.motorsport-developments.c...ancashire.html

 

i have only used power station as they were the only place to have a dedicated air supply for the top mount instead of just aiming it at car and hoping it would be sufficient.

http://www.powerstation.org.uk/

 

This won't help but:
I guess the problem with Subaru turbo cars with TMICs have on the rollers is heat soak into the TMIC. Having a cold air feed to the TMIC is one thing but heat from the engine is always going to rise vertically without airflow over the car.
I can only assume that with enough airflow into the TMIC a tuner can work around this.
Other than that then I can think of no specific reason why a Subaru would not be dealing with the simulated arena being presented to it that any other car would.
Stu, having read many articles you have written for Ford magazines, your expertise blows my mind (and I have a degree in engineering!). I'm not trying to teach you to suck eggs. I figured I'd write that little lot out for the guys on here to ponder.
Paul.

 

Thanks, will take a look now and see if they have any images.

That is absolutely correct mate, and one of the many problems such equipped cars are faced with on any dyno. My cell shouldn't suffer too much there as I have 40'000cfm going through the cell, exchanging the entire cells air content for fresh every 4 seconds. During testing this week, after ten back to back runs with closed doors my cell is only seeing a 1.5 deg C temperature rise above outside ambients. However, without enough volume of air flowing through the TMIC it still wont be doing anything for the charge temps so we are gong to not only be losing power but risking knock.

The engine surface needs to be maintained at around the same level as it does on the road in order to keep the TMIC core at realistic real world levels. We have tested this with some K-types and datalogging and our cell does an awesome job of replicating the road in that sense.

The problem with dyno colling is its still very much spot cooling when compared to real world conditions and that means a pressure differential between the TMIC's upper and lower surfaces. To elaborate a little - if we have 20'000cfm at 100mph going into the closed engine bay, but only 2000cfm going through the intercooler at 30mph, then the reality is, there is more likely to be warm air coming up through the intercooler from the engine bay than there is cold air going through it from outside. This needs to be balanced up as best as you can by specifying the correct size and speed TMIC feed pipe and air mover motor. (Each car differs of course and it depends on the available air exit path)

Kind words mate, thank you very much, its nice to hear people enjoy them.
I enjoy what I do and the satisfaction comes from learning how to do it properly. I tend to spend more time learning than earning though sadly. LOL

If you missed any, the full collection of 60+ articles are available for download on my website maybe some good toilet reading.

 

Don't know if it's still the same Stu, but, might be worth you paying Steve Simpson at Teg Sport a visit. He's not that far from you.

IIRC when I was last there, he had a separate fan with ducting specifically for TMIC use.

 

PowerStations solution................

 

For what it's worth, we found during testing a 22b with stock top mount that it didn't matter whether the car was on our dyno or on the road, the charge temp went through the roof anyway! The intercooling was just plain inadequate.
I don't think everybody realises that it's perfectly possible to cool a car on a dyno to the point where you think everything's going to be fine on the road when it most certainly isn't.
Charge temp monitoring. Essential in my book.

 

We have used a similar method, but it's worth pointing out that in use, the top mount intercooler only gets air from the front, over the bonnet.
Basically, a top mount intercooler isn't the full monty, and it's better to deal with that knowledge.

 

You can't argue with experience, attempting to overcompensate for a TMIC'S short comings doesn't alter the on the road variables.

dunx

 

Thanks - I've seen Steves mate,
I've probably seen them all to be honest, just hoping something will jump off the page as an amazing idea that I hadn't considered.

 

I totally agree Alan.
Anyone not monitoring a forced induction engines charge temps as standard when tuning shouldn't be using a Dyno period really.

 

From my experience the type of set-up that PowerStation employs for TMIC cars is efficient for the purpose intended. I.E. to provide adequate cooling as close to road conditions as possible, when sustained loading is present under formal mapping sessions. Put it this way.... it's better to have increased cooling than it is not having it. Dyno mapping is a harsh environment, so anything that can alleviate such conditions has to help. A road environment is less harsh.

The set-up PS employ is not to compensate for inadequate intercoolers, just to ensure that an environment is more comparable to the road, than it would be without.

Stu,
I'm not sure I agree with your "monitoring charge temps" being a must (which I assume is what you're alluding to). I have never had any mapper specifically monitor my ACT's whilst mapping and this has NEVER caused me, my engine or the performance and reliability attained any issues what so ever. I would argue that individuals who have mapped Subaru's over a period of time and gained experience of many set-ups, know what works and what doesn't and what to look for to ascertain if ACT's are a problem, without specifically monitoring them. Suffice to say the only mappers who touch my Subaru's are those which hold such credentials imo.

 

The problem you run into Shaun is unless you know what the charge temps are, you don't know if the ignition your adding Into the main tables is being removed again by the thermal management tables and thus when you add in your "known good" figure of say 18 degrees lead, but in fact only get 14 degrees crank lead because the act compensation table has removed 4 degrees... Leading to a "this engine is greedy" scenario and you thinking its perhaps low comp or the ring - bore seals are worn heavily.

The same situation goes for boost.
All O.E systems slow the compressor down to control engine thermals, that's one of the main reasons they have a boost control solenoid - so you set the boost to 2 bar, make your 400bhp and are happy. Hit the road test 20 mins before the customer picks it up and runs into "why the **** is this leaning off, knocking and running 2.3 bar on the road?" It was fine on the Dyno. Worse still - you DON'T road test it, so it blows up!!

I could elaborate quite extensively but I am trying to teach my 18yr old to cook a Sunday roast and, not having a TMIC to hand, need to use the oven right now! Back later. Lol

 

Unstand your first point about the thermal management tables, but is that assuming that (apart from using inlet air temp) your ECU is actually seeing ACT's measured.... this is not specifcally the case with most Impreza ECU's. I know most Impreza OEM ECU's don't read this (mine can as it has the sensor but with totally different ROM code and re-wiring is needed). I'm not sure if this has changed on the DBW ECU's. My ECU certainly has comp for IAT standard.

Boost I totally understand and also with regard to AFR's and KNOCK.... thus why road mapping/checking certainly makes sense as part of the complete process. Something that I undertake with the mapper whenever my car is "adjusted".

 

Intake air temp barely matters on most cars, only being used to trim between the extremes of Finland and Sub Sahara.
I've no idea why Subaru didn't use charge temp sensors, considering the sometimes marginal intercooling.

 

Sorry Shaun, When I am talking about calibrating, it's usually not marque specific as one hour I may be calibrating a 1973 fiesta with a lancer engine in, and after lunch a twin turbo F10 BMW M5. We do such a broad range of ECU's that I tend to just generalise as the physics and thermodynamics never change, just the method of dealing with them.

Anyway - In my opinion - air temp is very important to the way an engine runs.

If you use the ideal gas law you will see that the volume of a gas such as air is proportional to temperature (T) and inversely proportional to pressure (P). So if volume changes then density will change. The engine needs to know mass and not volume to calculate load. It can be done directly with a MAF sensor or indirectly with alpha-n or speed density.

Ref the scoob ecu - some cars indeed don't have them as the ecu's are intelligent enough to estimate ACT and adjust the VE tables accordingly.
At any given rpm/TPS point you have the VE table. The VE is an indicator of how much volume of the cylinder is occupied by air at the same T+P as ambient air. So a 2.0litre engine has 500cc per cylinder, a VE of 1 would be 500ml of air filling it, less then 1 would be less than 500ml and so on and if the ecu knows air density going in, and boost pressure/RPM then it can be referenced. However, this only works within the confines of the turbine / compressor / intercooler the software model was written for and goes out the window if you change any of them.

It's worth knowing and remembering that the air density changes by 10% for every 27 Deg C, so mapping a vehicle to a theoretically great afr of say 12.6:1 for max power on the Dyno with ACT's in the 60s will leave you at least 10% lean if the ACT's are only hitting 30's in real world conditions and were not calculated for during calibration.

As an aside, I was correcting a screwed up map on an Audi RS6 recently and just couldn't figure out why his top lines were so lean when the rest was pretty damn good. It transpired after frigging some inputs to test the thermal management routines that he must have had the exhaust manifold at 1000c + and in fact he had been taking fuel out of the main table that the poor old ecu was raking in to try and cool it down. It had a turbo smart E Boost 2 fitted so its normal method of dropping turbine speed had already failed. Again - the results of not testing important parameters whilst Dyno testing.

I wonder how many tuners even ensure their test cell pressure is optimal when mapping? Not bloody many I bet!!

 

Yeah they're the ones
Very interesting reading. In fact I use your "blowing a mouth full of water through a straw" analogy at work every now and then

Anyway, your new windtunnel dyno: does this not give sufficient total air flow over the car to simulate real road speed then no? (I'm not knocking it, I'm just trying to understand)
I read on your website and on FB about the 3 different airflows in your dyno environment and assumed the large capacity airflow was to simulate real world air speeds. I'm also assuming it's not a recirculating system (like an aerodynamic testing wind tunnel I believe) which can achieve higher speeds. Would a system like that not solve the problem you're questioning by providing a total air speed over the whole car giving real world air intake and cooling fluidics? And if the air heats up as it's being recirculated, as Alan says, it shouldn't matter TOO much? (Obviously keep your exhaust gas removal system )

Again, I'm not knocking your brand new system at all, you've obviously looked into this at great detail and chose what you considered to be the best, I'm just interested as this isn't my normal type of engineering.

Paul

 

Good, Im genuinely pleased to hear it mate. I eventually gave it all up as I ran out of things of interest to say after 6 - 8 pages a month for 5 years, so I am pleased what was written came in handy for some people.

Hi,
To be brutally honest, the wind tunnel analagy was more to explain to Joe Bloggs reading the site that the air comes in the front, and out the back and is never recirculated. Its not at all windy enough to be a wind tunnel. I should probably find a better way of explaining that on my website as a genuine wind tunnel will have the same air speed at the top and sides as the bottom and middle (Like wind) and mine certainly doesnt.

As per probably 99.99% of dyno cells, its run by various fans and they are all to one extent or another spot cooling fans. (Engine cooling / exhaust extraction/ Cell air movers) so no - whilst it does an awesome job of maintaining cell temps by ridding the cell of latent heat, it still wont provide full on airflow through a scooby intercooler as it stands. Thats going to need another spot cooler.

 

I cant believe only 1 fella on scoobynet has a picture of a car being dyno'd with a TMIC air supply?!

 

No pics Stu but got a link to a video of Prosports setup in Manchester

 

The rolling road cooling system at RCM is very effective on my tmic, it blows cold air regardless of outside temps through a wide bank at the front of the car. I haven't any pics but just to say before the blower was switched on my ACT sensor was reading around 40c and within a few seconds of the blower being switched on the readings had dropped to around 12c.
I run a water/meth injection system which when running full boost helps to keep ACT's down, so not a good example but the temps on the RR are what I would expect on the road.
Trev

 

Apologies mate.... didn't want to come across as a ****. Just wanted to underline that us gimps on here are only going to give (mostly) reference to Scoobs.

Whilst I understand about VE I don't know how (for instance) the OEM Subaru ECU deals with these variances, if you're stating that any appropriate formulae is based on the oem turbo and intercooler efficiency.

The only variable I'm aware of is the Air Temp Comp. portion, which I assume would be used to adjust fueling based on the IAT's (if were talking about the majority of the Scoob ECU's). I can only assume that "knowledge" helps defining this based on spec utilised.

Anyway.... I'm starting to pick your brains on mapping strategies and de-railing your thread.

I'll put the gimp mask back on and return to the corner!

 

You know me mate, it's all just adult discussion and when I am in the mood I enjoy it, and when I'm not, I just don't reply. You know how it is - if you have nothing good to say keep your mouth shut. It can be quiet in my office at times. ROFLOL

Yes - the Scooby ecu takes temp as part of maf and extrapolates the rest of the data into a theoretical model that will work amazingly well. The good thing is, it has a good knock control system, if it didn't have, they wouldn't have risked that route. I don't know the Scooby ecu as intimately as some, but I bet it does a damn good job if it, providing you don't canibalise the main fuel tables whilst its compensating for something you have missed.

As you quite rightly say, there are professionals on here doing a wicked job with this ecu day in day out and the lads on here wanting other than a quick stage 1 should be appreciating these peoples talents and spending their money in their general direction.

And taking pictures of their ****ing intercooler cooling feed pipes for my damn topic!!

 

LOL

In short though Stu.... I don't know of anyone else that specifically has additional cooling for TMIC on the Scoobs.... and I've personally used a few dyno's as you may well have heard.

The PS set-up has a front facing fan, rear extraction and then a fan mounted in the ceiling with a durex connecting it to the TMIC (which is clamped on). Works well being in the ceiling and used only as and when it's needed. The "nodder" effectively concertinas on itself back into the ceiling and a trap door is closed up to keep it safe.

 

Powerstation setup is nice, I like it.

I must admit I am surprised that very few are spot cooling the TMIC's. I will continue to dig around but I think a sensibly sized air mover will do an adequate job, my only problem at the moment is room to port it out to atmosphere.

Mind you - I guess I could strap on a turbo-zet!
(Anyone remember them? LOL)

 

When my Impreza was on the RR there was the typical large fan which had boards fitted channeling the air flow (sides and top) The top board board extended out so it fitted above the scoop and directed air into the scoop.

This way you can make up the 3 sided shroud and fit it to the fan when you get an Impreza.

 

Stu - you're obviously making a big investment in this, and I'm damn sure you aren't doing it as a hobby. Therefore it has to pay for itself. Re mapping, the Elephant in the room is the same old Jumbo. On the one hand we have mappers who say it's best to map on the road, then you find them all using dynos at some point or another, usually when it really matters.
We know where we sit with this, considering as we do that an often busy public road isn't the place for car tuning. What do you think?

 

thats not a fan,





this is a fan,



It's flippin noisey as well lol

 

Stu, couldnt you get another of the front facing fans and have a kind of 'swan neck' shroud made up for it to vent at the scoop?

that way you will still have the airflow through the bumper and around the engine, and hopefully the airflow over the closed bonnet, simulating real world driving and airflow characteristics??

just an idea, but i have no idea if its any good lol.

 

They can work well. To be fair, my existing fan may work perfectly well as it is, and until I get an Impreza on there with a TMIC fitted, I wont truly know - I am planning a "better" alternative mainly for mapping as pro mappers are booked to hire my cell and god knows what they will turn up with. mazda MPS are another problem car in this respect.