Tuning and mapping on similar engine to actual one?

For discussing MicroSquirt (TM) configuration and tuning of fuel parameters (including idle valves, etc.).
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bpcampion
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Tuning and mapping on similar engine to actual one?

Post by bpcampion »

Kinda confusing, but I have a 5.0L engine with 4 valves per cyl. that I am putting together for a 928. It will see boost, but I was thinking tuning would be safer to add the boost AFTER the innitial tune.

BUt the engine also needs to be broken in, and so I have another engine, a 4.7L in another 928, that I could run MS on, that is kind of a daily driver. It only has 2V per cylinder, so the efficiency is a bit different, but not that much I think.

With the fact that the first engine must have a good enough tune to be broken in quickly upon startup, would it be a good idea to make a tune on a similar engine, and then move the system over? Ar ethere large differences in tune between engines of almost the same size in different cars?

Thanks.
LT401Vette
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Post by LT401Vette »

I would stick with your first plan, you should be able to break it in without boost. If you tune to the 2v engine, your ve table could be off quite a bit especially at WOT. Atleast enough so that I wouldn't want to run it with boost.
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bpcampion
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Post by bpcampion »

Thanks.

has anyone ever been able to "borrow" a tune file and make it work for the first few runs while really getting its the nat's bum?
FoundSoul
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Post by FoundSoul »

Sure-- you can often use a .msq file of another vehicle to get your car running IF:

1) Everything about the engine's condition, mod list, etc is exactly the same.

2) If was built on the same firmware version as you are running (if not you can still use much of the information from it, and import the VE/Spark VEX tables)

3) Preferably you're using the same version of MegaTune that was used to create the file-- I don't think this is AS critical as firmware version but it's a best practice in my opinion.

4) You don't just 'plug-n-go' without testing it out first and making sure it really is a good fit for your engine. Any number of variables that you may or may not think of could throw it off enough that if you jump into WOT runs without fine tuning for your ride you could pop something.


On item #1 above-- you can use a file for a setup that's NOT exactly like yours but similar. First set the constants for your engine and then still expect it to need tuning for anything more than idling and maybe easily rolling up and down the neighborhood street. And you could probably use some fine tuning for even that.


If all things are truly equal-- yes you can drop a file from car to car with no problem, I've done it. But so often something is missed that makes things not-equal and it's better to exude caution ;).
Jerry a.k.a. 'FoundSoul' /// **Now Available** MicroSquirt EMS!
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bpcampion
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Post by bpcampion »

Thanks Mr. Soul.

The reason I would be going down this "copy" path is not to reduce work - it is to try and mitigate some of the concerns about doing two things together that may not be well-combined - A new tune on a NEW engine.

I was thinking that if I have a "round about" tune from, say, a 4V mustang, or something like a large vave 2V motor of the same or similar size, it would help me break in the engine quicker - with some percentage less "large gap" changes that would need to be made in the first 30 minutes of running, which is where I will need to run in the new pistons rings, etc.

Thanks!
FoundSoul
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Post by FoundSoul »

Totally understood and not a bad idea at all-- I've known of people to use a carb to break in a motor and then slap the EFI gear on for the same reason. Expecially when somewhat new to EFI.
Jerry a.k.a. 'FoundSoul' /// **Now Available** MicroSquirt EMS!
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bpcampion
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Post by bpcampion »

Its a serious concern of mine.

Breaking in the engine properly is a large hurdle for me on this MS thing. Well, that and the decision to put in the MSII chip.
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