2g mas, 2g pistons, 550cc, 190lhp, SAFC

[want_a_gsx]

ok i am somewhat confused and have some noob questions for ya:

"On a 1g, you want to tune for no knock, end of story.

On a 2g, you want to tune for timing advance. You want to keep the timing advance graph on the logger above, say, 15-16 degrees, and you want it to be nice and smooth.

2g's only have 2 fuel trims, a long term fuel trim (LTFT) and a short term fuel trim (STFT). The STFT varies with the O2 sensor, an the LTFT goes for every rpm range. Since the STFT directly effects the LTFT, then you can just add the two together, and tune from there. For example, if the LTFT is +20%, and the STFT is -5%, you are at approximately +15%."

since i'm gonna be working with 2g mas, do i tune as if i had a 2g car?

also with the 2g pistons, what kind of boost would i be able to run without getting too much knock. i understand that higher compression = more knock. anyone out there have some type of experience with this kind of setup?

i dont have any of these things on my car yet, but i am gathering as much info as possible before i do this. getting my motor rebuilt and dont want anything to be screwed up. i figure i would ask about it now, instead of being clueless when i do get all these mods in...

"Now, you want to use baseline corrections for fuel injectors. If you have 450's, leave both tables at zero. If you have 550's, put them around -10%. If you have 660's, usually around -18% would be a fine starting point. If you have a hacked MAS, then you will want to use about 5% MORE than these values."

it says to put 550's around -10% on the safc, but what about the 2g mas...does that affect the numbers i have to put in the initial safc settings(to be on the safe side)?

and yes i searched A LOT but didnt find many people stating their experiences on tuning, knock and fuel trims, when it came to talking about 2g mas as well as 2g pistons in a 1g. i know this is a little long, but its mainly because of the quotes from
Definitive Piggyback Tuning Guide thanks

 

[burtreynolds]

I understand what's meant by "tune for no knock in a 1g" but at the end of the day if your tune nets 2 deg timing advance with no knock, that's not a very good tune. You want to tune for no knock with the most timing advance possible at WOT ~ 18-20 deg is the norm on a good tune with decent fuel. You will still use this method with a 2g MAS in a 1g.

 

[JayRolla]

The 1g's have more aggresive of timing map and you should hit 22-24* without timing control. But like he said 18-20 max is about perfect with the most boost possible and no knock. Now once its tuned this way its still not good enough. Thats a base tune, you need a WB02 to get a perfect tune. Dyno would be the best or buy one and go crazy.

I have pretty much your same setup and yes you wont beable to push as much boost as you would with 1g pistons. Just tune your car like its any car. It has the 2g pistons and with our timing map its harder to tune, unless you can control the timing and put a cap on the advance. You just need to start playing with it. Before my pistons I was runing 14psi no knock. After the 2g piston swap I can run more than 12psi witout knock.

 

[Gromit]

ok i am somewhat confused and have some noob questions for ya:

"On a 1g, you want to tune for no knock, end of story.

On a 2g, you want to tune for timing advance. You want to keep the timing advance graph on the logger above, say, 15-16 degrees, and you want it to be nice and smooth.

2g's only have 2 fuel trims, a long term fuel trim (LTFT) and a short term fuel trim (STFT). The STFT varies with the O2 sensor, an the LTFT goes for every rpm range. Since the STFT directly effects the LTFT, then you can just add the two together, and tune from there. For example, if the LTFT is +20%, and the STFT is -5%, you are at approximately +15%."

since i'm gonna be working with 2g mas, do i tune as if i had a 2g car?

also with the 2g pistons, what kind of boost would i be able to run without getting too much knock. i understand that higher compression = more knock. anyone out there have some type of experience with this kind of setup?

i dont have any of these things on my car yet, but i am gathering as much info as possible before i do this. getting my motor rebuilt and dont want anything to be screwed up. i figure i would ask about it now, instead of being clueless when i do get all these mods in...

"Now, you want to use baseline corrections for fuel injectors. If you have 450's, leave both tables at zero. If you have 550's, put them around -10%. If you have 660's, usually around -18% would be a fine starting point. If you have a hacked MAS, then you will want to use about 5% MORE than these values."

it says to put 550's around -10% on the safc, but what about the 2g mas...does that affect the numbers i have to put in the initial safc settings(to be on the safe side)?

and yes i searched A LOT but didnt find many people stating their experiences on tuning, knock and fuel trims, when it came to talking about 2g mas as well as 2g pistons in a 1g. i know this is a little long, but its mainly because of the quotes from
Definitive Piggyback Tuning Guide thanks

1G's have Lo, Mid, & Hi Fuel Trims. Follow what that tuning guide says for getting those set for a 1G, starting with the Lo Trim. Having a 2G MAF doesn't change what you want the fuel trims to be set to - as close to 100% as you can get.

As for your SAFC settings, the 2G MAF essentially balances out the 550 cc injectors. In other words, the 550's flow approximately 18% more fuel than stock & the 2G MAF flows approximately 20% air more than the stock 1G MAF. If everything is functioning correctly & you have no boost leaks, your SAFC settings should be close to 0.

Can't help you with the piston question.

 

[JayRolla]

Yea they should be close to zero, but it can use some adjustments. With my 550's and just the 2g maf I was running way lean still.

 

[Gromit]

Yea they should be close to zero, but it can use some adjustments. With my 550's and just the 2g maf I was running way rich still.

Yes, this is correct - every car is different. I was just presenting the theoretical values & that's why I qualified the statement by saying if everything was functioning correctly, no boost leaks, etc. Since the OP doesn't even have the parts yet & is just trying to grasp the tuning concepts before he does anything I just addressed his specific question. However, your real-world experience with a similar set-up is useful info he can file away & refer back to when it comes time to tune his set-up.

 

[want_a_gsx]

looks like its gonna be a whiiiiile before i can run this setup.

reoccuring electrical problems today on top of the whole blown motor crap...either find a solution for electrical problem or drop in a fairly running motor and sell the damn car...then buy another one, which starts the cycle all over again....ahah

thanks for all the info,very helpful.

 

[spartan]

I had the same setup in my galant except I have 560's from an evo. I was running extremely rich down low. Finally I got my keydiver chip in and figured that this would solve the problem...well it didn't. So I now have to put on an AFPR, jeff said that more than likely my 190 pump was over running the stock regulator. So I will have to wait until I get a chance to install that before I know if it will work for sure.

 

[nightspeed87]

over run has nothing to do with the chips capabilities.
Yes you will need a afpr to deal with that. I have a highpressure 190 over running it like its a 255. Sometimes it pops and once my friend said he saw fire spark out the exhaust as I changed gears. It will only make you run really rich like on decelleration, and between shifts, shouldnt hurt your WOT performance though, unless you have other fuel issues on top of that.

 

[JayRolla]

Yea overrunning the pump should not effect your WOT performance, just idle, between shifts and at cruising.