Dyno Pulls...

[Djason]

Had an opportunity to make a few pulls at my buddies new shop here in Houston. Jayson Cohen, owner and founder of Motorsport Technologies, has once again decided to follow his never ending enthusiasm, passion and intense desire of making something great even better in the automotive industry.

After stepping away from the game for the past 7-8 years, pursuing his entrepreneurial spirit in other ventures, many knew (or at least hoped) he couldn't stay away forever.

Jayson see's MANY things to be improved upon in our potent little Caddy. From the induction and exhaust side to theconservative factory tune. Mike (NewEra) has already shown this in all his threads as well. Looking at the stock tune it's amazing the LF4's are performing like they are.

Welcome back my friend!

Base line pulls before the mods begin.

(Actual)

(Corrected)

 

[Hib Halverson]

Figuring 15% for parasitic loss, the engine in your car is making about 505-hp SAE way more than the rated 464.
Interesting.

Can you post the air-fuel ratio plot from those dyno runs?

 

[Djason]

Yeah I was thinking the same thing Hib. Told the guys after the pulls, that was close my Z06 numbers when stock. Couldn't believe it. Not sure on exact % for drive train loss but I was figuring 12-15%. I'll get with Billy or Jayson on the AFR. Was super lean at beginning of pulls from what I remember. Guess nature of the beast with DI...? We also couldn't believe the timing through the pulls.

SAE Corrected

 

[Hib Halverson]

Yeah I was thinking the same thing Hib. Told the guys after the pulls, that was close my Z06 numbers when stock. Couldn't believe it. Not sure on exact % for drive train loss but I was figuring 12-15%. I'll get with Billy or Jayson on the AFR. Was super lean at beginning of pulls from what I remember. Guess nature of the beast with DI...? We also couldn't believe the timing through the pulls.

For manuals, I've used 15% for mid-90s or newer cars. Older stuff, I used 18% because transmissions and axles weren't as efficient.

For automatics, you have to use a larger correction, 19% for newer and 22% for older.

I'm guessing your's is a manual.

On AFR, at the bottom of the image you posted above, I can now see what looks like AFR data, but there's some red and blue lines right at the end which don't make sense. If you can get your dyno guys to provide some data that's easier to understand that would be helpful.

Based on what's there in that image, it looks like the ATS-V is typical of GM cars in that there is a big delay in the onset of PE. Also, the AFR at WOT, even after the delay seems pretty lean if you were using E10 gasoline.

Recently, I pulled the cal out of mine using HPTuners. PE enable is at 3000 RPM and the ramp-in is .05. Unfortunately, it's unknown at this point what those units are, but I do know that the smaller the number, the slower the commanded AFR reaches PE. There's also a PE delay with a base of 10ms which is then decremented in steps. It's fascinating to look at other parts of the cal. Indeed the LF4 has pretty sophisticated engine controls and whomever calibrates it better know what they're doing. For example, there are separate and different MAF tables for each MAF sensor. That ought to drive guys building aftermarket airboxes nuts. I suppose your tuner already knows all this stuff, so I'm I guess I'm digressing.

In any event, the commanded PE AFR is 13.35 which, based on my experience with port injected engines is pretty f'ing lean. Whether that's the case for a GDI engine...I'm not sure.

 

[Djason]

Yeah I noticed that at the end of the pull as well. Might be just a glitch. I'll try to get some more info to share. Thanks for all the info. For a tuned port injection yep that's pretty lean. Different animal with DI for sure.

When it's all said and done...tune, downpipes and a good quality CAI...these cars should be one helluva little hot rod.

 

[Hib Halverson]

Yeah I noticed that at the end of the pull as well. Might be just a glitch. I'll try to get some more info to share. Thanks for all the info. For a tuned port injection yep that's pretty lean. Different animal with DI for sure. Looking forward to seeing the full potential out of this thing. We'll start on it after my first track day early next month.

When it's all said and done...tune, downpipes and a good quality CAI...this should be one helluva little hot rod.

My wildass guess is an aftermarket air filter assembly that really works well is not going to be cheap or easy becuase of the two MAFs and their different curves. Also, it's interesting to note that the two intake tracts are divorced until before the filters. There's may be a message in why GM did that.

I think those of us looking to mod the LF4 are going to have to be careful of aftermarket companies which have a hard-on to be the "first" on the market with products that DIYs typically crave. I think, like in the past, it's going to be fairly easy to make noticable differences at WOT on the dyno. The difficult part comes when one tries to make noticeable changes which also work well on the road, don't cause driveability or significant emissions quirks and don't compromise durability. Just the fuel pump problem many GDI engines have will confound those modifying the engines, especially in the midrange.

Lastly there is the warranty issue, which, of late, has become complicated. Since the late '00s, GM engine controlers have had the ability to log that a calibration change has occured, how many times a cal change has occured and if that cal was OE or not. This loging data exists whether the OE cal is currently installed or not. GM techs can read that data with the TECH2 or the MDI. GM put out a TSB back in June that requires dealers check that logging in cases of engine, engine part or emissions part failures on engines in '05-'06 Corvettes, any '07-16 GM vehicle equipped with a V8 engine and 12-16 Camaros with V6es, and if evidence–not just the actual cal, but just evidence of a non-OE cal is present, the warranty is voided. Currently that procedure is not required with the LF4 but it is a possible problem if an ATS-V owner makes a warranty claim on an engine-related system and the dealer suspects engine is mods might have caused the failure.

I'm not saying "Don't modify" but I am saying, doing so may not be as easy as we think with the LF4.

 

[Djason]

My wildass guess is an aftermarket air filter assembly that really works well is not going to be cheap or easy becuase of the two MAFs and their different curves. Also, it's interesting to note that the two intake tracts are divorced until before the filters. There's may be a message in why GM did that.

Lastly there is the warranty issue, which, of late, has become complicated. Since the late '00s, GM engine controlers have had the ability to log that a calibration change has occured, how many times a cal change has occured and if that cal was OE or not. This loging data exists whether the OE cal is currently installed or not. GM techs can read that data with the TECH2 or the MDI. GM put out a TSB back in June that requires dealers check that logging in cases of engine, engine part or emissions part failures on engines in '05-'06 Corvettes, any '07-16 GM vehicle equipped with a V8 engine and 12-16 Camaros with V6es, and if evidence–not just the actual cal, but just evidence of a non-OE cal is present, the warranty is voided. Currently that procedure is not required with the LF4 but it is a possible problem if an ATS-V owner makes a warranty claim on an engine-related system and the dealer suspects engine is mods might have caused the failure.

I'm not saying "Don't modify" but I am saying, doing so may not be as easy as we think with the LF4.

Agree on the CAI that will eventually come to market. Will not be cheap and not sure if it'll be the most cost effective mod for HP but there is definitely room for improvement over the factory set up.

 

[Djason]

Few updates...

Quick trip to the local track for a private rental.

Had a hard time getting the 60' down to where I wanted as the rpms would not come up smoothly, having a dead spot when trying to bring up the revs, not going past 3800-4000rpms. Found out, as the day progressed and trying different launches, you have to come up (almost to clutch engagement) in order to free up the rpms. Strange why this happens. Maybe a tq management thing. After finally figuring out a few things on the last few runs, I had already made 14 passes, I figured that was enough for the day. 12.35 @ 113.xx was the best I had for the day with a crappy 1.94 60'. Could have probably knocked off a few more .10's in stock form with a better 60'.


X-pipe delete and Vibrant Resonator install...

 

[Rob]

Guys,

I was able to recover this entirety of this thread by going into the database and cleaning out some kind of JavaScript code that Djason had accidentally copied from PhotoBucket. The entire thread can now be viewed.

 

[Djason]

Guys,

I was able to recover this entirety of this thread by going into the database and cleaning out some kind of JavaScript code that Djason had accidentally copied from PhotoBucket. The entire thread can now be viewed.

Awesome thank you Rob! Wasn't sure what exactly happened. Strange as I copied and pasted image link as I always do with zero problems. I'll be more careful next time.
chug:

 

[Rob]

Awesome thank you Rob! Wasn't sure what exactly happened. Strange as I copied and pasted image link as I always do with zero problems. I'll be more careful next time.
chug:

:blinzel:

 

[Hib Halverson]

Guys,

I was able to recover this entirety of this thread by going into the database and cleaning out some kind of JavaScript code that Djason had accidentally copied from PhotoBucket. The entire thread can now be viewed.

This kind of stuff is why Rob gets paid the exhorbitant salary he gets.
ocker:

 

[Rob]

Lol! I wish!!!