Let's see how bad Scot can mess up his Sonic!

[Scot]

I can't spend $$$ for a downpipe...

I really, really want a downpipe, but I can't justify $220 for something I think I can build...

I've got plenty of stainless O2 bungs, all I really needed was this order from Jeg's. I'm hoping to remove the DP tonight or tomorrow to make a jig/fixture for my homebrew build...
:banana:

 

[rdss]

Nice! Looking forward to seeing the finished product.

 

[sx sonic]

Indeed, let the custom DP come forth!

 

[Graham]

If you build it.. they will buy.

Sent from my DROID RAZR HD using Tapatalk 2

 

[Graham]

I will buy..

Sent from my DROID RAZR HD using Tapatalk 2

 

[Stew]

Scot, can you change the DFCO parameters? Isn't the stock setting pretty mild, only cutting off something like between 1800 to 1100 rpms? I wonder if you enable DFCO at the upper rpms if that would help with the 1 to 2 shift grind by slowing down the rpms quicker?

Edit: As I'm thinking about this I don't think it will help much with the 1 to 2 grind simply because the shift process happens so fast, that DFCO enabled or not, there is not enough time passing for the rpms to drop an appreciable amount.

 

[Scot]

Stew -
Excellent, excellent insight! GM already uses DFCO to drop the RPM as fast as possible during shifts (plus, it is extra fuel economy). One thing to also remember is that there is so much energy stored in the flywheel, it doesn't want to change speeds to readily, either.

I wonder if Preloader still grinds with his aluminum flywheel?

 

[ecohauler]

A lighter flywheel won't help with the shift grind either, as it's part of the engine, which is disconnected from the transmission when the input shaft is supposed to be slowing down during the 1-2 shift. A lighter clutch/pressure plate might help, though.

 

[Scot]

Update:
42lb injectors are here and an alcohol sensor is in the mail...
I have not had any time to pull the close-coupled cat and build the jig/fixture yet.

***** Does anybody have their old cat they pulled out and wouldn't mind measuring the 3-bolt flange to send me dimensions?*****

 

[sx sonic]

Update:
42lb injectors are here and an alcohol sensor is in the mail...
I have not had any time to pull the close-coupled cat and build the jig/fixture yet.

***** Does anybody have their old cat they pulled out and wouldn't mind measuring the 3-bolt flange to send me dimensions?*****

Give me a few and I'll see what I can do.

Edit: All I had access to was a steel rule so these measurements are not the most precise so I'm not sure how much of a benefit they'll be.

The threads appear to be 8mm (5/16") diameter.

The 2 closest together studs have a center to center of 2 3/16" or 56mm. They are both located 1 1/2" from the center of the flange (where the center of the exh pipe is).


From the bottom stud to the stud on the right (as viewed from the rear of the car towards the front) the center to center is 3 9/32" or just under 3 5/16" or ~83.5mm and is located 1/34" from the center of the pipe.

From the top stud to the stud on the right is a center to center of 3 1/2" or 89mm.

For a visual reference the 3 studs make an isosceles triangle. Only 2 of them are equidistant from the center of the flange. The right stud is further from the center.

 

[Scot]

Awesome! I think this will do nicely!

Thank you!

 

[Scot]

Work and life have been hectic. I've continued tuning the engine and been adding things here and there. I hardpiped the SAB with the help of Stew - can't tell if it made any difference or not.

I'm running into a funny problem tuning - when charge air is cool (like on my morning commute) I push enough boost to get an over-voltage error on the TIAP, then go into reduced power mode. The same tune on a summer afternoon pulls strong with no problems, so I need to find a good way to scale my boost.

 

[Italianjoe1]

Have you diabled that code (p0238) in the editor? I hit it yesterday during my 2nd revision and just popped the stock tune back in for now as I won't be driving the car until the weekend anyway, she'll be taking it to work.

I plan on adjusting the boost back down around 235-240kpa where the computer won't panic, but the car felt very strong until it pulled boost lol.

I need to try one pass with that code disabled and see if it still goes into limp mode, it shouldn't and would allow me to run the higher boost down low for some serious torque fun.

The code parameters set when you have high boost under 3500rpm for more than 2 seconds, if you adjusted the demand tables accordingly to not hit that hard until over that rpm you could avoid it without turning it off.

 

[Preloader]

so I need to find a good way to scale my boost.

Electronic Boost Controller?

And as stated, the aluminum fly had no positive effect on the 2nd gear grind, but does allow the revs to drop much more similar to a traditional manual car application.

 

[Italianjoe1]

The car has an excellent boost control system built in, you just have to set it up right. Chris from HPT has a nice write-up in the 1.4 Cruze tuning thread about which tables to target to get your desired boost ramp.

I dunno if you guys are familiar with ETC cars, but all modern ones hang the throttle open on purpose when you lift off the throttle, reason is to allow in enough air to burn the fuel that's still present, so you don't get any unburned hydrocarbon emissions.

It contributes to that "laggy" feel we all hate about electronic throttles, but it's the way of the future and will not be changing. There's also little you can do to modify around it, aside from changing your driving habits and being a tad more patient when shifting.

 

[Scot]

Have you diabled that code (p0238) in the editor? I hit it yesterday during my 2nd revision and just popped the stock tune back in for now as I won't be driving the car until the weekend anyway, she'll be taking it to work.

I plan on adjusting the boost back down around 235-240kpa where the computer won't panic, but the car felt very strong until it pulled boost lol.

I need to try one pass with that code disabled and see if it still goes into limp mode, it shouldn't and would allow me to run the higher boost down low for some serious torque fun.

The code parameters set when you have high boost under 3500rpm for more than 2 seconds, if you adjusted the demand tables accordingly to not hit that hard until over that rpm you could avoid it without turning it off.

Don't bother - disabling it just kills the code / light, but leaves you in limp home mode.

Not sure where you found the parameters of how the code sets, but that is *very* good information!

 

[Italianjoe1]

Don't bother - disabling it just kills the code / light, but leaves you in limp home mode.

Not sure where you found the parameters of how the code sets, but that is *very* good information!

I don't even recall where I saw them, either HPT or google searching but I thought it was interesting.

I know I was getting really strong boost and short-shifting the car manually, so it makes sense to me.

And yeah I kinda assumed you would still get the limp mode, the tune I've built for testing next has reduced max boost for now. No need to burn it up with 25psi anyway.

 

[Scot]

Joe -
I found a way around the boost limit tonight, but now I'm out of injector duty cycle

Sent from my XT1080 using Tapatalk 2

 

[rdss]

Scot, are you looking for a spare/back up motor incase you push the 1.4 a little too far? A built motor might not be a bad idea seeing that you're pushing it to the limits, which is great by the way. Between Preloader, you and a few others the 1.4's weak spots should start to become evident so that they can get beefed up.

 

[Scot]

I should!
Funny thing is that I have way too many projects for my own good - and I keep finding more. :banghead:

I don't know how feasible it would be, but if I blow it up, I'd look into dropping a big block in it. (2.0L )
I already took measurements of the current Malibu's front subframe...

Sent from my XT1080 using Tapatalk 2