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In a couple of weeks I hope to be getting my new LSX 454 running in my 98 Camaro with an 02 ECU. I may be a bit premature asking the question but I just want to get my head around it all: The start up tune is set up for a 92mm throttle body; I will be using a 102mm throttle body. Could some one please point me in the right direction of what should be done to tune the throttle body in and tune all the tables that would be affected by the changes.
For sure the base running idle airflow table, cracker/follower tables. Then the MAF/VE or just VE depending on your setup.
Is it going to be DBW or cable?
Your ETC scalar may need to be tuned. I have a DBW 416 Ci LS3 that I'm getting tuned currently. I just went through the process of trying to dial in my ETC scalar, because the few methods of math did not end up being the correct values, had to find it with trial and error.
I made a post about it 2 weeks ago with what I did and how I found the correct value: https://www.hptuners.com/forum/showt...-Scalar-tuning
Also,the ETC Area Scalar will need to be changed due to the T/B size increase.
Thank you everyone for your response's. I understand that the throttle sensor also needs to be adjusted for the throttle blade in the new throttle body.
I understand updating the VE table through data logging but I'm not up to speed when it comes to the idle airflow table, cracker/follower tables and ETC Area Scalar or adjusting the throttle sensor. Could someone please take the time to explain how to I get the new values and put them to use. I assume these would have to be acquired from data logging once I get the engine running.
I believe that the flow difference is about 28% between the throttle bodies, for the purpose "only" of getting the engine running close to the mark at first start, would a 28% increase across these parameters be any good as a base till the correct values can be determined and inserted into the tables.
the ETC scalar I found to be closest on my 102 DBW TB was 0.0210.
I merely added 2 grams of air to my base airflow and that was plenty to get the car idling. It will adjust STIT automatically to keep itself idling. So I wouldn't mess with many tables related to airflow until you get the ETC scalar dialed in. It'll start up without it.
I set the ETC scalar to 0.0210 from 0.0255
As a note, you may have to tune it as based on the thread I posted. My calculated value for a 102 is 0.00150 ish. Clearly I was no where near it
I have had time to have a better look through your post and take much of it in, I found it very informative and actually learned a bit which is what it's all about. I am actually running the same intake/TB setup down to the injectors just the LS7 variant as I assume yours would be the LS3 Fast intake. After having a read I noticed that the start up tune which is running the 90mm TB actually is still running the 78mm OEM value 0.0255 scalar value, I had a look then at my other Gen III tunes from professional tuners, my drive car a Gen III tune 428cid HSV Grange with 92mm TB and a friends Gen III tune 427cid S/C LS running 92mm TB, both are still running the original scalar value 0.0255 as would be used with the original OEM 78mm TB from the retired 5.7s, so I have a little work to do once I finish the tune.
I have adopted 0.0141 scalar for the start up tune as the math in my mind corresponds well to what I recon GM would choose after seeing the math on the OEM 78mm TB. If things don't work out I can always go back to the average
For a 90, you can generally get away with stock values I noticed. There is a certain degree of error you can bake into the other idle parameters, but I found with the 102, it was just too much error and I could never get it to idle right
I understand what say; I've noticed most tunes tend to leave out the scalar and as you say 78-92 isn't a massive increase whereas 78-102 is a huge air flow increase, I believe almost double.
Both those other cars I mentioned with the 92mm throttle bodies are running around .680 lift with 241/243 duration. I was just hoping that; by altering the scalar a little on those engines I could make them idle a little more moderate.