Tuning for Torque

[Bondy]

I recently took off my mpfab downpipe + cat and zzp intake.
The car seems to have alot more torque/pick up since i put the stock equipment back on.

Im running the budget tune, maybe going with a full tune would be able to bring back in some more low end.

As it is now with only a budget tune and full stock it seems better as a daily driver..

What have you guys experienced with going to full tune?

Is a more restrctive exhaust better for low end?

 

[Eric Smit]

it would seem to make sense that the aftermarket parts would shift the powerband up.

 

[sonic_braaappp]

not to say that a more restrictive exhaust is better for low end, but more so that upgrading exhaust components to a more free flowing unit increases top end horsepower.
For example, on the cobalt ss supercharged, the long tube header gave it more top end power in exchange for a noticeable amount of bottom end, whereas the midlength header increases top end power with out taking as much bottom end, but also without providing as much top end increase.

but overall, there's an OK amount of low bottom end power. enough to get you going then the cars power really kicks in up top.

 

[Swordsmith]

Trifecta's budget tune and the full tune are almost completely identical, until you start adding significant aftermarket bolt ons. At first, tuning specific to your car helped, but most people report that once Vince had a few dozen Sonic tunes under his belt that the budget tune and full were the same... and when they would send in their data logs to be reviewed, they would just get "you are fine" back instead of an updated tune.

I have not heard that Vince does a lot of fine tuning on request either; it is possible to tune for a variety of different driving goals, but for the most part, that doesn't seem to be something he's offering.

What might be happening is that your mods changed the car enough that it isn't well tuned with the "budget" tune, which is after all designed for a more or less stock car. A full tune could help, if that's the case, not because the tune itself is any different, but because you could datalog and get an adjusted tune that better suits your modified car.

 

[Bondy]

Thanks..yeah datalog should help a lot.

The throttle reponse with sab and stock exhaust seems a lot cripser than zzp and anaconda exhaust. I dont know but maybe the turbo can spool quicker when the system has less volume...

 

[94383Z71]

I don't see any way those mods would create a loss of low end power- I haven't noticed it. They do free up more top end, potentially shifting the peak and you may be noticing that. But I doubt they actually took away any low end- but I could be wrong.

 

[MPFab]

Based on the dyno data I collected while developing the Anaconda, power and spool are less at all ranges with the stock exhaust vs. The Anaconda, on the stock tune. The Anaconda offers much less restriction and allows to turbo to come up faster. This improves low end. I had a budget tune for a couple weeks and it was terrible. Boost was erratic and the car was choppy when accelerating until 4.5k. The dyno graph looked like an EKG. The full tune was much better. 90% of that was gone.

 

[cndctrdj]

You forgot to mention how Hp tuners fixed everything hahaha

 

[Bondy]

MpFab

Thats exactly it. Boost is erratic and acceleration is choppy.
I guess this is a good case for going full tune.
At what stage do you guys recommend using upgraded injectors?

 

[NewZJ]

Once you get the full tune the injectors are almost maxed out, so just about anything extra would show small (very small) gains. If you plan on installing upgraded exhaust, intercooler, intake, porting the manifold, then go ahead and get the injectors when you can as they will show more gains

 

[ranvette]

One of the most powerful 1.4Ts on the cruze forum is running stock injectors at around 230 wheel HP.The 42s were taken out it runs best on stock injectors.

 

[SonicBRO]

Did that cruze have the upgraded "cams" done to achieve that?

 

[ranvette]

No i think he is running Vtuners larger Turbo as i remember and meth injection with ported intake.I would say he may have the upgraded valve springs now to

 

[Sneakerfix]

No i think he is running Vtuners larger Turbo as i remember and meth injection with ported intake.I would say he may have the upgraded valve springs now to

Who's cruze is this? Dyno sheet? Haven't heard about that the only one I know is only making 215whp.

Stock injectors at that power should be close if not over 95% duty which isn't good

 

[ranvette]

its smorey

 

[rcmn0022]

If they are running water meth, they may have it tuned slightly more lean and that would allow for it to have enough room on the stock injectors.

I was running 10:1 AFR when my car was almost maxed on the stock injectors. I've been successful with running the car at 12:1 AFR but I have been running it more at 11.7:1 AFR and the stock injectors were peaking at 78% or so when it was at 11.7 AFR and making significantly more power than at 10:1 AFR.

 

[ScarabEpic22]

If they are running water meth, they may have it tuned slightly more lean and that would allow for it to have enough room on the stock injectors.

I was running 10:1 AFR when my car was almost maxed on the stock injectors. I've been successful with running the car at 12:1 AFR but I have been running it more at 11.7:1 AFR and the stock injectors were peaking at 78% or so when it was at 11.7 AFR and making significantly more power than at 10:1 AFR.

Yea...10:1 on E10 isnt a good target even for a turbo motor, way too rich. Not surprised you're seeing more power (and Im betting it feels smoother/cleaner) under WOT.

I havent logged mine enough to pay attention to IDC, I definitely will be doing some more in the next few weeks once I finish up another project (non-Sonic related). I have seen what AFR looks like on a couple Trifecta tune, but Ill have to go look at some more.

On the 230fwhp Cruze on stock injectors, has the owner said what the IDC is on it? There are a few tricks you can use to really push a set of injectors, but it's not the right way to do it and comes with its own set of issues. Above 100% IDC (really a little lower) the injectors are wide open all the time, if you're right on the line you can still make power and keep AFR acceptable by fudging the MAF/VVE and/or "PE raping" in boost. Does it work for big dyno numbers? Yes. Is it a good, long term solution that is reliable? Absolutely NOT.

 

[rcmn0022]

Yea...10:1 on E10 isnt a good target even for a turbo motor, way too rich. Not surprised you're seeing more power (and Im betting it feels smoother/cleaner) under WOT.

I havent logged mine enough to pay attention to IDC, I definitely will be doing some more in the next few weeks once I finish up another project (non-Sonic related). I have seen what AFR looks like on a couple Trifecta tune, but Ill have to go look at some more.

On the 230fwhp Cruze on stock injectors, has the owner said what the IDC is on it? There are a few tricks you can use to really push a set of injectors, but it's not the right way to do it and comes with its own set of issues. Above 100% IDC (really a little lower) the injectors are wide open all the time, if you're right on the line you can still make power and keep AFR acceptable by fudging the MAF/VVE and/or "PE raping" in boost. Does it work for big dyno numbers? Yes. Is it a good, long term solution that is reliable? Absolutely NOT.

For what it is worth, the 10:1 AFR was on Trifecta and they said it was all okay. I'm making about the same power at 18psi now on 11.7:1 AFR compared to the 23psi on Trifecta.

 

[ranvette]

I run about the same AFR.Trifecta just left it dumping fuel like the factory tune more or less when its at wot

 

[ScarabEpic22]

For what it is worth, the 10:1 AFR was on Trifecta and they said it was all okay. I'm making about the same power at 18psi now on 11.7:1 AFR compared to the 23psi on Trifecta.

Yea...that's not so good. My TBSS was pig rich from the factory as well, cleaning up the fueling netted a few more hp and a "cleaner" acceleration as well.

Glad to hear you're making more power at lower boost! Now you can start adding boost back in and seeing if it makes more power, might have to adjust the spark timing as well.