Looking for a good EFI tune file for a 3.0 engine with ITB's

[frank912]

Hi All,

Just finished the rebuild of my 911 engine and the installation of ITB's and an MS3X (mega squirt) system in my porsche 911. System runs fine at the moment but everything is tuned very basically. I am still in SD mode but that is also because I do not really know how the program the ITB mode table.

Would love to get a tuning file of some tables (fuel and advance) of a well tuned similar 911 engine. Not to copy this but to learn from it and to find out what changes I should make and play with the system. I prefer not to ruin my fresh engine by playing with the advance table by myself :-). I will dyno the car as soon as it is roadworthy..... Just want to learn more about the variables and there impact on the engine.

My set up details are:

porsche 3.0 engine 10.3:1 compression
964 cams
ITB's
Fully sequential injection
Edis 6

Thanks a lot in advance,

Frank

[Tippy]

What size ITB's? That would make a difference once you tune on ITB mode.

[Mark Henry]

Well.... the Fully sequential injection isn't much of a benefit on an air cooled, it adds fuel economy driving below 3k rpm (watercooled cars) but a on an aircooled you shouldn't be running much below 3K. Over 3K sequential has no benefit over batch.
If you want to argue the point first go to the MS FAQ's and look up sequential vs batch.

Those cams aren't overly radical, bit more lift but IIRC the same duration as SC cams, so you should be able to use the MAP sensor, but with the ITB's if you have a poor vacuum signal you will need to tune in alphaN. Tippy's question is likely because too big of ITB's will make the vacuum signal worse. I'd try both ways and see which works better for you. Poor vac and using MAP often gives you a lean condition when you stomp on the gas.


You'll likely will need some dyno time, even with a good base file, pretty hard to tune on a LT and drive at the same time.

[jpnovak]

for ITB mode it takes a lot of work. You will not find a tune file that works. You have to setup specifically for your engine.

You must tune the engine with speed density and working TPS. Then workout the proper TPS% at each cross-over point using datalogs. Then setup both switchpoint curves using the data.

If you don't understand how it works you will not be able to tune it correctly.

Honestly, Just like Mark says the 964 cams have a wide enough lobe center that you will have a strong vacuum signal. IMO you will get better results using SD mode. The vacuum signal will respond faster than TPS anyway due to the low volume of the intake tract under the throttle plate.

large throttle bodies can be easy to tune except for the transitions where large swept area combined with fast throttle movement will dump a lot of air into the intake and it can be challenging to get tip-in and acceleration enrichment correct.

[safe]

ITBs tricky... My best advice, if it start and runs, book a tuning session (4-8 hours) and get it there on a trailer.

Done it on both my cars, best spent money ever...

[chrisbalich]

how timely this thread is. I should be starting assembly of a nearly identical engine in the next 4-6 weeks. *albeit with 9.3:1 compression and individual coils in lieu of the 6pack

[frank912]

Hi All,

Thanks for the replies. Regarding the ITB's: these are 42mm. I am aware that sequential does not bring much, but like it how it makes the engine idle and pick up....

My SD is quite ok. I have quite ok changes in Kpa so I should be able to tune it well. Was just wondering what changing to ITB mode would bring. I am aware how it should work and also know how to get the switchpoint out of the software.

Currently the engine runs ok. Advance is very on the safe side, so this needs to go up. Do not want to melt the engine but the engine could do much better. High RPM's is still too lean.

Will dyno it for sure, but was just wondering whether some proven tunes would give me some clues where to go to and what would be possible (tuning wise)......

So if somebody is willing to share his map's/tune for a comparable set up.....would really appreciate it.

Thanks so far.

Frank

[shamrok]

Tracking, I’m also getting my motor back together and hoping it’ll be in the car and wired up within a few weeks. A base tune as a starting point would be great.

3.0
9.3:1 compression
964 cams
CCM Triumph ITBs
Microsquirt with Denso COPs in wasted spark config

[jpnovak]

There are some definite tricks to tuning ITBs. Though they are not that much different than tuning any engine (common plenum) once you understand the principles of what you are doing.

I will add that scaling of your MAP (load) bins is very important to ITB tuning. They will not be evenly spaced. You should notice a steep upturn in your fueling delivery as the efficiency of the ITB flow takes over from throttle opening. This is as the manifold pressure starts to approach atmospheric. Typically this is right near the 90kPa pressure isobar. Funny how that can be a default setting on the ITB_Mode switchover curve... This is where you need more resolution to accurately control fuel over the rapidly changing pressure and amount of fuel required to control it.

You also need to make sure the load bins (MAP) cover the dynamic range of your engine. Don't put a 10kPa bin on there if you only pull 35kPa under decel. And yes, you might see more than 100kPa if your engine is efficient enough and air density is high enough.

I will also say that if you want to determine your ITBMode switchover points - do not wait until you have started the steep upslope on the fuel curve. You will have some abrupt transitions as the ECU switches tables.

The same can be said for the RPM bins and even more so at boost onset on a turbo car.

I have baseline distributions for different intakes. Then tune to a very well running car. Then adjust and scale the tables to match the shape of the fuel curve, and finally fine-tune with proper scaling.

Do you have a knock sensor? If so, it is easier to play with how much timing you can add into the engine.

[Bigtoe32067]

I guess it's what all the cool kids are doing. I'm about to start on a 2.7 (or 2.8) with ITB's, ms3x, cop, 9.5 to 1, unknown at this point Web cams. I'm just about finished with a stock rebuild on a 3.0 sc and I'll need to sell it to fund the rest of the 2.7 build.
Tony

[al lkosmal]

Frank,
Lot's of good info in this thread and I'll add my $.02..... regardless of mode, if you have a tune that has your 911 running pretty well, I think you are ahead of the game if you move forward to refine that tune to meet your specific engine configuration/characteristics. I supply good start-up tune files with the systems I provide and they work great, to get you up and running quickly, but then the real tuning begins. There is no substitute for gaining a basic understanding of the principles involved, data-logging.....reviewing the logs, understanding the results and the basics of how to modify the tuning to improve the results. This can be done on a dyno, but excellent results can be had (and better in some cases IMHO) by driving/data-logging/modifying...rinse and repeat until satisfied with the results.......It is definitely a process.

regards,
al

[frank912]

Hi Al,

Thanks a lot for your $.02!! You are correct: your start up tune file is very good. That is what I am running currently (slight modifications) on the great set up that you supplied!!

The car should be ready for testing this week so I will have a few test runs to see what comes out of the data logging.


Regards, frank

[Neil Harvey]

Originally Posted by Mark Henry

Well.... the Fully sequential injection isn't much of a benefit on an air cooled, it adds fuel economy driving below 3k rpm (watercooled cars) but a on an aircooled you shouldn't be running much below 3K. Over 3K sequential has no benefit over batch.
If you want to argue the point first go to the MS FAQ's and look up sequential vs batch.

Those cams aren't overly radical, bit more lift but IIRC the same duration as SC cams, so you should be able to use the MAP sensor, but with the ITB's if you have a poor vacuum signal you will need to tune in alphaN. Tippy's question is likely because too big of ITB's will make the vacuum signal worse. I'd try both ways and see which works better for you. Poor vac and using MAP often gives you a lean condition when you stomp on the gas.


You'll likely will need some dyno time, even with a good base file, pretty hard to tune on a LT and drive at the same time.

If I may chime in here.

I disagree with that blanket statement that sequential control doesn't matter much. Typically you can trim each cylinder for best torque both for fuel and ignition. Most manifolds use in aftermarket Porsche EFI conversions need all the help they can get, and having the added control does help, a lot.

For NA applications, consider configuring EFI with the main axis RPM V TPS with MAP as a correction. The TPS will change verses RPM so much quicker than MAP, so your response etc will always be crisper.

[mikedsilva]

Originally Posted by frank912

Hi All,

Just finished the rebuild of my 911 engine and the installation of ITB's and an MS3X (mega squirt) system in my porsche 911. System runs fine at the moment but everything is tuned very basically. I am still in SD mode but that is also because I do not really know how the program the ITB mode table.

Would love to get a tuning file of some tables (fuel and advance) of a well tuned similar 911 engine. Not to copy this but to learn from it and to find out what changes I should make and play with the system. I prefer not to ruin my fresh engine by playing with the advance table by myself :-). I will dyno the car as soon as it is roadworthy..... Just want to learn more about the variables and there impact on the engine.

My set up details are:

porsche 3.0 engine 10.3:1 compression
964 cams
ITB's
Fully sequential injection
Edis 6

Thanks a lot in advance,

Frank

Frank
I am running AEM Infinity and had the car tuned.. not sure how the mapping compares bewteen makes, but happy to email you my tune so you can view for yourself.

[wblroostertail]

Looking to connect regarding the Conda Green 911, scott@ramsaycapitalgroup.com

[Mark Henry]

Originally Posted by wblroostertail

Looking to connect regarding the Conda Green 911, scott@ramsaycapitalgroup.com

Just an FYI but It's not wise to put your email on an open forum.

[winders]

I don't know.....with the MoTec M130 setup running sequential fuel injection I am getting much better (20% maybe more) fuel mileage with my new race engine that has 100 HP more than I did with my old race engine running a Haltech in batch mode. I am running an 8000 RPM redline and only see 3000 RPM or below when idling or putting around the paddock.