IFR limits?

[JnJSpdShop]

Tuning a 2006 Corvette and I see the IFR table limit is 63.5 lb hr. Would it be correct to just put the largest values possible in the IFR table and then adjust the MAF table to adjust for the additional injector size? Would this require adjusting every other air flow table?

[DSteck]

Any airflow value in the calibration has to be scaled down in the same proportion that the injector flow rate is scaled down. Then, if you want your cylinder airmass calculation to end up the same, I think you have to scale down your cylinder size by the same percentage.

However, you may end up having to shift your timing table because if you need injectors that big, you'll probably run out of headroom for the CAM as well.

[madvette08]

Tuning a 2006 Corvette and I see the IFR table limit is 63.5 lb hr. Would it be correct to just put the largest values possible in the IFR table and then adjust the MAF table to adjust for the additional injector size? Would this require adjusting every other air flow table?

What you can do is put 63.5 lbs in the IFR table, then figure out the difference. So if you have a 80 lbs injector you would do 63.5 divided by 80 will give you a 20% difference. So you would then go to the Flow Rate Modifier Vs Volts and put 1.20.

Ian

[5_Liter_Eater]

Does that work? I have heard of doing that but have never seen confirmation that it actually works, IE: all the airflow values are still accurate.

[madvette08]

Sure does work, if that table doesn't work there are other flow rate tables you can change. Basic its telling the computer there is 20% more flow rate then 63.5 lbs/hr.

Ian

[DSteck]

This is interesting... although I thought at the end of all the calculations, it was limited to 63.5 lb/hr. Hopefully somebody can give a definite answer one way or the other!

[RWTD]

Ian, what pcm are you referring to? *Supposedly* this works on the 4-bangers, but there has still never been any official info on that. From my understanding, however, it doesn't work in all the pcms. The 63.5# limit still comes into play on the V8 vehicles. At least this is what many have posted on here that have tried it.

Also, for those who didn't know, when DSteck refers to CAM, he's referring to Calculated Airmass, not your camshaft.

Tuning a 2006 Corvette and I see the IFR table limit is 63.5 lb hr. Would it be correct to just put the largest values possible in the IFR table and then adjust the MAF table to adjust for the additional injector size? Would this require adjusting every other air flow table?

Myself, Greg, and others, covered that in these threads pretty well:

IFR Value Limit Workaround - Parameters to scale?

Ratioing down the airflow values. HELP !!!

And I recently made a post here that explains additional tables that are referenced by airflow (certain knock sensor parameters), as well as the Trans pressure tables, which will be affected when you do the airflow scaling:

http://www.hptuners.com/forum/showpo...4&postcount=22
(post #22)

Also, I *highly* suggest you purchase Greg's training DVD, as it covers EVERYTHING you need to know to perfectly tune your car in yourself, and has all the proper calibration data for those injectors you're using.

http://www.summitracing.com/parts/SME-DVD-1/


I hope this helps, so please ask any further questions that you may have.

[JnJSpdShop]

Also, I *highly* suggest you purchase Greg's training DVD, as it covers EVERYTHING you need to know to perfectly tune your car in yourself, and has all the proper calibration data for those injectors you're using.

http://www.summitracing.com/parts/SME-DVD-1/


I hope this helps, so please ask any further questions that you may have.

Thanks I already I have purchased the DVD and watched it a few times. There are some tricks I never thought of but I think it is pretty basic. The injector info disc is great, but I am a little disappointed that it didn't really cover much in the way of idle tuning or table scaling

[RWTD]

His Advanced training class goes over that in detail, and as you may already know, you get the full purchase price of the training DVD credited towards the advanced training class.

[eficalibrator]

As James mentioned, scaling and more in-depth idle control strategies are a big part of the advanced class. There's just too much going on to put it in a beginner's DVD for that stuff. It really gets explained MUCH better in person, with a live vehicle example in front of us to demonstrate.

If you nail the injector/MAF/VE stuff as the DVD shows, you'll find that tuning idle should be much, much easier since the PCM is now reacting to actual g/sec airflows instead of some botched, half-assed unknown scale of g/sec in the low flow regions that results from bad injector info and poor tuning practices. The first step in gaining control is to stop lying to the PCM about how it should make its adjustments and just let actual physics run the show.

[JnJSpdShop]

As James mentioned, scaling and more in-depth idle control strategies are a big part of the advanced class. There's just too much going on to put it in a beginner's DVD for that stuff. It really gets explained MUCH better in person, with a live vehicle example in front of us to demonstrate.

If you nail the injector/MAF/VE stuff as the DVD shows, you'll find that tuning idle should be much, much easier since the PCM is now reacting to actual g/sec airflows instead of some botched, half-assed unknown scale of g/sec in the low flow regions that results from bad injector info and poor tuning practices. The first step in gaining control is to stop lying to the PCM about how it should make its adjustments and just let actual physics run the show.

Might an advanced DVD be on the horizon, or maybe an Advanced tuning session to coincide with the PRI show in Orlando, maybe before or after. Otherwise I simply don't have the time to attend unless it was in the WNY or Toronto metro area