What: I am looking for a Faked 3-Bar tune for a 00+ cavalier (ld9 specifically) or directions on how to do it yourself.

I have just spent about 1.5 hours searching and reading thru other posts... so please dont tell me to "search"

I was thinking "1 bar = 14psi of boost, 2 bar = 28psi" Opps... oh well... i forgot to calculate for the 14psi difference in gauge pressure... so i realize i only have a few more PSI before i max out my 2bar sensor. soo.... I guess i am going to have to jump to a 3 bar after all. I didnt spend all this time and money to create this boost monster just to stop at 14psi.

So i know some of you are running over 14psi. I have read of "faking a 3bar" by scaling values, i heard mention of a 3-bar tune that shifted made, i have seen people talk about tuning it themself. lots of posts on what map sensors to use for this... but so far i have not seen any detailed write ups on HOW TO DO A 3 BAR FAKE. or links to instructions, or where to get a tune already started that way. everything to come up in a search is just kinda general info... "just scale anything map based" well there is alot of stuff in HPT.. anyone got a list of what all should be scaled?

I would love to get my hands on shifted's 3-bar tune. that guy is amazing. But really i would be content with a decent "how to" or a demo file i can use as a guide to try it myself.

Any of you guys running over 14psi, i would very much like to talk to you about the woes and joys of breaking the 14psi barrier. How did you do it, what would you do differently if you could? Any tips or suggestions? Any good resources or reading on this anywhere?

I don't have a 3 bar tune, the only way to "fake" the 3 bar tune is to start with the s/c reflash, and even then I don't think it can be done with the stock PCM. You'd lose so much resolution that you'd have absolutely no fuel control when you aren't in boost.

I think most people running over 14 PSI are doing it on a 2 bar sensor and then using some kind of extra fuel control to compensate.





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Hmm, that is odd, i could have sworn at least a few different posts refered to "shifted's tune for 3-bar"
I guess if you didnt make one, then i guess there wouldnt be one... that is disapointing, i have read some great things about your work.

I curently have the GM Reflash for the SC (2002 Z24 with mp45) so i at least have that much...

So if everyone stays with a 2bar, and adds their own fueling... what methods are available to accomplish this?

Would you just tune for up to 14psi in HPT... and then use something else to work above that?

doesnt HPT scale between and beyond set cells? (ex. so if 200kpa is 18 and 210kpa is 19 and that is as high as the chart goes... if you hit 220kpa, wouldnt it assume 220 would be 20?)

I thought that is how it works... i know you wouldnt have much fine tuning control above your highest values... but it should still supply some fueling shouldnt it? or would it not even know you exceeded your max value, as the sensor would just peg and it would think you just stayed at say 210kpa no matter how much higher you went?

Does HPT even allow you to adjust the tables themself? instead of VE tables evenly spaced every 20 KPA, could you shift the cells to areas where you needed more resolution?

I know some of my tuning books talk about shifting the cells to where you need more control. i dont know if HPT allows that. or not. I dont see a way to do this. But then again, isnt this the whole premise behind "faking" so i guess there has to be a way to do it... unless all the fakers are a bunch of fakes themself.

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doesnt HPT scale between and beyond set cells? (ex. so if 200kpa is 18 and 210kpa is 19 and that is as high as the chart goes... if you hit 220kpa, wouldnt it assume 220 would be 20?)

No, after it passes the extents of the table it continues to use the last value it found in the table.

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or would it not even know you exceeded your max value, as the sensor would just peg and it would think you just stayed at say 210kpa no matter how much higher you went?

That's right, the sensor would peg and it wouldn't know how much actual air is going into the engine after that point.

Quote:


Does HPT even allow you to adjust the tables themself? instead of VE tables evenly spaced every 20 KPA, could you shift the cells to areas where you needed more resolution?

No, HPT does not allow you to change the scale of the tables or the size. This would require a custom OS and HPT isn't willing to do that for us (not enough money in it for 4 cylinders, they have these types of OS's for the LSx's).

Faking the 2 bar basically means sticking a 2 bar in the car and then you have to realize that the cell that you are working in, if in KPA, is actually twice the value that is on the side. For example, in the table at 50kpa you really have 100kpa going into the engine, so you have to put the appropriate number in there to tune for that. There is no rescaling of the actual tables, just the data that's in it.







4cyltuner.com - Information Source For 4 Cylinder Tuners
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ken soggs wrote:... unless all the fakers are a bunch of fakes themself.

There's sadly probably a TON of truth in that statement. lol.

-Chris-



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