Using Maths channel to calculate turbo airflow

[Hugh]

Wanted to say hello since I am a new Syvecs user and also to post something up since I have found it really hard to find my way around the Syvecs platform.

I feel that a "How to" section that gives baby steps on how to find your way around would be invaluable to all users. If you fall at the first hurdle it is really hard to keep going.

Simple things like the lack of a full list of what the parameters do is nothing short of unbelievable.

In the spirit of sharing, I wanted to show the steps I used to calculate the airflow through my turbos, it might help others struggling with the basics of using a Maths channel in SView.

I have an R35 GTR with a new engine build that I am working with and wanted to see if it was possible to work out the airflow through the Turbos to calculate where I am on the Compressor Map with a view to setting the maximum boost level.

I could not find any instructions on how to use the Maths function online, but turns out it is really easy and in my case very useful.

The principle I wanted to explore was that since the ECU delivers an injector duty cycle to maintain an air / fuel ratio, I should be able to calculate the flow of fuel and therefore it should be easy to calculate the flow of air.

Here is the result, the Orange line shows the air flow though one of the turbos through a 3rd and 4th gear pull



Here is the formula I used 14.7*lam2*sqrt(12.47267*relFp1/2999)*fuelDutyPri1/100*6/2

Here is the Math channel input screen in SView - Click Math > New and you can type it in



Here is the turbo compressor map on my car that shows it will deliver 60lbs of air /min.

The calculation shows I am at 50lb just now, so can safely increase the boost.



To help you understand the formula, it is effectively Air fuel ratio * current fuel consumption :-

= Air fuel ratio * injector flow * injector duty

Getting the units to match is the first challenge since the Compressor Maps are in lbs of air flow per minute.

I will describe each part of the formula so will hopefully not lose you.

14.7*lam2*sqrt(12.47267*relFp1/2999)*fuelDutyPri1/100*6/2

14.7*lam2 calculates the air fuel ratio from Lambda.

14.7*lam2*sqrt(12.47267*relFp1/2999)*fuelDutyPri1/100*6/2

sqrt(12.47267*relFp1/2999) calculates the flow through the injector for the current fuel pressure.

The formula I used is square root of new flow = old flow squared * new pressure / old pressure.

I have ID2000 injectors, they flow 2225cc/min at 43.5 psi, this is 3.531667 lbs of fuel per minute. The compressor map is in lbs air per minute, so the units are important.

12.47267 from the formula is 3.531667 squared, relFp1 is the differential fuel pressure (fuel pressure - boost) 2999 is the 43.5 psi in the Syvecs units, millibar or something like that.

14.7*lam2*sqrt(12.47267*relFp1/2999)*fuelDutyPri1/100*6/2

fuelDutyPri1 = injector duty

14.7*lam2*sqrt(12.47267*relFp1/2999)*fuelDutyPri1/100*6/2

100*6/2 = 100 takes the injector duty to a % when you want to multiply it. 6 = six injectors. 2 is because there are two turbos.

So, having done all that I am not sure how to save the Maths calculation so that it is permanently attached to the view I shared above.

Thanks

Hugh

[Slowie]

To save that view to include the new maths channel, simply go to Worksheet and Save Worksheet, give it the same name as the currently selected one ("Tuning" in your case), and choose to overwrite it.

[Hugh]

Thanks Slowie,

Appreciate the help

Cheers

Hugh

[RICE RACING]

Hello Hugh,

A nice effort there, one thing to help smooth out the output is to put a filter on the various inputs in the formula
This is one I applied below to an E85 set up (9.76:1 stoich) and to suit injectors in that car at 3800mb base FP. 4cyl turbo application.

9.76*filter(lam1,0.85)*sqrt(7.04882655*filter(relFp1,0.85)/3800)*filter(fuelDutyPri1,0.85)/100*4

Z axis has turbo speed v PR v air flow

[Ryan.g]

Hugh,

Good to see you playing with the software. Could you explain more what you struggled with and will address it in a Help video or manual as this kinda feedback is valuable for getting new users up to speed faster.

Have you seen the Help videos section btw

http://www.syvecs.co.uk/support/help-videos/

Ryan

[Hugh]

Thanks RICE RACING,

Had a play with the filter on a single parameter, it's very powerful.

Tried it on the whole formula, but it didn't work, then looked back at your formula to see that you have used it directly on each parameter.

The formula you created is exactly where I started, but wanted to add in the slight change on variable flow due to fuel pressure changes, so added in the square root of new flow = old flow squared * new pressure / old pressure to correct, I played around with it on a spreadsheet for a while against the declared flow values on the Injector Dynamics flow chart to be sure I was applying it correctly.

I also plan to run E85 and had given some thought to the formula that should be used, but hadn't fully resolved what the effect of the oxygen contained in the fuel should be.

Clearly the AFR is just as you have it in the first part of your formula, but was not sure if there was any effect of the oxgen being delivered in the fuel rather than through the turbo compressor, my feeling was that it will drive the turbine harder, but will have no effect on the compressor flow calculations which means your formua is correct.

Cheers

Hugh

[Hugh]

Hugh,

Good to see you playing with the software. Could you explain more what you struggled with and will address it in a Help video or manual as this kinda feedback is valuable for getting new users up to speed faster.

Have you seen the Help videos section btw

http://www.syvecs.co.uk/support/help-videos/

Ryan

Ryan,

I have struggled with the complexity of the Syvecs platform.

The logic of every aspect has been challenging despite having a base map set up in my car.

The lack of a full list of what the parameters are measuring is a real obstacle to my understanding and is still an unnecessary complication.

Currently, I cannot work out how to change the boost or improve the accuracy of the boost control since I cannot figure out the logic of how it was set up.

Am sure that I will get there, but it is many times more complicated than I expected.

For me a quick start guide that gave some basic steps in the following format would be really valuable e.g.

Closed loop lambda Enable = Run Mode Fuelling > Corrections > Closed Loop Lambda > Overall Enable.

Closed loop lambda Target Map = Run Mode Fuelling > Corrections > Closed Loop Lambda > Wideband Sensors > Base Target 1

There are probably only 10 or 15 quick start steps that would give you access to ignition, fuel and boost control features.

As it is I have not understood how to access most of the settings that I need to tune the car properly.

Thanks

Hugh

[Slowie]

Hi Hugh

Yes, one can definitely tell that Syvecs comes from a professional motorsport family, where they expect the end user to be a professional motorsport engineer, who can figure it all out, or already knows it all. The Syvecs team is working hard to make things easier for the first time user, but as it stands some prior EFI and mapping knowledge still helps greatly. Do you have any previous EFI experience? Have you installed or mapped other ECU's? I have not done mapping myself, but have installed quite a few different ECU's from scratch for friends, and got the car to the point of running, so learning a new system is not daunting anymore.

Have you viewed all the help videos in the link Ryan posted? This one in particular will help, as you can assign simplify the interface to hide all unused items https://www.youtube.com/watch?v=X8tLO4CbcE0. You can also make shortcuts to the commonly used items in SCal (F2-F8), to speed up navigation. Also go through the Syvecs Manual, which although it is mostly a collection of posts from this forum, gives lots of useful hints on strategies, including a good explainer on boost control.

http://www.syvecs.com/downloads/Syvecs% ... 20V1.1.pdf

Also go through the older posts on this forum, there is lots of good info in the older stuff, and not so many topics as to make reading most of them a tedious and time consuming exercise.

Other than that, when I got stuck with some silly things an email to support@syvecs.co.uk has always returned very quick answers.

Can you list the items you want to access to tune the car? We can help with where to find it. Some items may just be labelled slightly differently to what you expect.

Paul

[west_minist]

It took me good 1 month of studying it day and night to understand the strategy and when I final got around it, I was amazed it tooK so long. But one greatest accomplishment, I saw other ems like child plays except simtek.

The help vids was tremendous and printing out the manuals.

[RICE RACING]

Can't speak for anyone else but in my own experience it took me not 1 month but more like 1 year solid, everyday, and working on multiple projects to get where I would say I am 'competent' to use the LR/Syvecs and not just implement strategies but understand how they work and have a chance to refine them to a level worthy of what the designers intended.

It's not 'easy' for people who have not had extensive experience in this system, though they are 'easy' to map as they say for the end user once you are familiar with it.

I've seen 'many' people/shops take on one of these ECU's and promise a customer the world only to deliver them an Atlas in reality.
They do make a motec look like a microtech by comparison, the features are great, but you cant expect to be proficient in it across all of the item features like is possible on lesser ECU makers offerings.

For newbies and others who may read this, its not uncommon to have over 70 iterations of a calibration by the time you work it to a high level of refinement, on a complex install where you are controlling a gearbox, turbocharger, traction control then you can double that. Hour's? these are not computers that you charge a customer a flat rate and a run in tune and final power tune LOL! more like its an on going support deal, just like a professional race team does, you have the basic run up, then optimization, finally development, its an ongoing process and most end users don't have the ability nor the time to invest in that side of things and are happy to pay a professional to manage that side of the power train (set up, control, development, analysis etc).

It is what it is, I LOVE! the system, its the best I have ever used and I have first hand experience with similarly regarded 'top shelf' Pectel MQ12 and Bosch MS* systems. I hope they never change the software as its pretty much perfect. You don't realize it at first but once you have to work with it for hours on end on a daily basis its greatness shines through every time.