brentil

Seems like a lot of speculation going on here, the thing is though this engine has been out for over a year now in the Solstice GXP and Sky Redline.

I thought I'd share my wealth of knowledge on the subject to get you guys going on the right foot since we've made a lot of findings over the last year. Feel free to post questions and I'll answer them as I have time. I'me the admin for SolForum and SkyRoadster so you can be assured the info I'm stating is as solid as it's going to come. Being who I am I've made some contacts with GM and have gotten to talk about this engine a good bit with them.


This is a seriously complex engine with a lot of very complex control schemes that make it react in a way to certain mods you wouldn't have really expected it too. We've found a lot of simple mods that involve air intake have been kind of counter productive (unless you can get the car tuned which isn't 100% available yet). CAI, inter cooler piping, boost controllers are very notorious for causing Limp mode (engine disables boost completely and greatly alters timing). So far only exhausts and intercooler upgrades have proven to be truly effective with this Bosch controller keeping gains over time and not causing the dreaded CEL. Once full tuning is available it shouldn't be as much of an issue but the Bosch controller and the control schemes for this engine are very complex.

The LNF uses what is referred to as a Torque based management system. The engine uses a 3 dimensional graph of torque values and controls the turbo based on torque demands. So say for your altitude and temperature the engine only needs to create 16 psi to fulfill the current torque needs the engine will stop at 16 psi. Usually people in higher altitudes see higher psi since they need to compress more at higher altitudes to meet what a car at lower altitude needs. This control system has been found to cause certain mods as mentioned to also not produce as much power as expected because the control system ends up limiting the car.

The Borg-Warner K04 Turbo is a small turbo with a very quick spool. Some Audi and VW cars also use this turbo (however a different trim level) in some of their cars. GM likes to throw out the "260 ft-lbs available at 2000 RPM" however the number I prefer to state is 250 ft-lbs available 1500 RPM. We've seen the numbers and proven them ourselves on dynos that this engine is a powerhouse off the line. However being a small turbo we're already very near the compressor map limits at 20 psi. If you're wanting to build big power (400+) on this car you'll have to switch out turbos for sure. The LE5 2.4L engine has been proven from various vendors like Hahns that 350+ is possible on a stock LE5 which has parts that are definitely not as strong as the LNF which is superior to the LSJ engine in several ways. After market tunes have shown the K04 can reach 23 psi on a regular basis along with a higher redline to reach about 300HP on a stock engine with just a tune.

BSR offers the PPC tuner and Westers has a tune out for GXP/Redline already. HPTuners has a beta release but it can't fully control the engine yet. The tuning is still very immature and not full featured at this time. Once this main item is nailed down we will finally start seeing the true ability of the LNF engine and mods for it. The BSR's tune pushes the car to 23 psi peak and raises the redline to 7000 RPM for 1st and 2nd gear. Their tune has been dynod at 265 HP to the rear wheels on a Solstice GXP which comparing various dyno graphs the RWD GXP shows about a 14% drivetrain loss. 265 + 14% = 302 HP. There is currently some rumblings about possible Stage kits from GM but nothing official yet. A couple weeks ago however was the SCCA Club Racing Nationals which the Solstice took 1st in SSB and the Solstice GXP took 1-2-3-4 in T2. Talking to the people who raced the Solstice GXP in T2 GM was on hand with their sponsored teams and were helping the independents with engine tuning also. T2 allows for unlimited boost in turbo/supercharged cars, and according to the people racing GM removed all of the Torque limitations and ratched the boost up to 26 psi on the stock engine and turbo. A quote from one of the racers at the SCCA Nationals;

They've shown that the turbo is capable of 26 psi for race like environments with cars prepared for those types of events. Who knows what this does to the longevity of the turbo/car though seeing as how these races are only an hour long.

Things to be aware of with the LNF engine.

• Turbo builds boost to demand levels, so depending on your region you may never see the full 20 psi. Seeing 14~17 psi on average is normal and within functioning values. You're still making 260 HP without having to hit the max 20 psi.
• Yes the clicking is normal from the engine. The LNF uses a cam driven fuel pump with a high pressure solenoid to provide the 2000+ psi of fuel pressure the direct injection system requires under load. The clicking is the solenoid opening and closing and is a common feature of all DI engines (Mazda 2.3L, BMW 3.0L, Cady 3.6L).
• Check your Turbo and intercooler tubes and check them often especially with modified cars. GM used a couple of T-clamps but for the most part they're cheaper screw clamps and are known to pop off.

I've got a 3" cat-back with no muffler/resonators on my LNF, all be it on a Solstice GXP. This engine freakin rocks. You can expect some nice gains from going to 3" tubing. The removal of the exhaust doesn't help as much as moving to 3" the engine is much more flow limited right at the turbo then it is at the outlet side.

YouTube video of the exhaust.
http://www.youtube.com/watch?v=qvqSgeEu2gg

Here's my before and after dyno comparison chart. I gained 16 HP peak and 5 ft-lbs peak at the rear wheels from the exhaust alone. However if you notice I gained about 25 HP and 25 ft-lbs after the peak.

REIGN SS

Very good info!

Spectral

Wow useful stuff im liking it.

jgarciarivera

iTrader: (1)

Now this info gave us some light prior the release of the LNF cobalt. Good info BTW

REIGN SS

Yes, it sounds like they are going through what .net did for the first year or so that the Cobalt was out.

hawlyns711

iTrader: (2)

i have a question...what does LNF stand for exactly? just the engine code?

REIGN SS

yes...

ZeroShinohara

Very useful information indeed. Thanks for posting it

Let's just hope those tunes are at 100% when the ss/tc comes out. I'm pretty sure some ouf friends here will show up with tuned cars only a coupe of hours after driving away from the dealership

Archie

Nice info. I knew all of that because I have been doing research on the Solstice forums, but nice for everyone who doesn't know where to look.

In regards to tuning. Has anyone notified HPT that Chevy is bringing out the LNF in the Balt and HHR, because that is more cars using the same programming. I think letting them know would help to speed up their process and be 100% ready by the time the new SS comes out.

REIGN SS

Im sure they know about the HHR SS, but i dont know about the balt

Spectral

i would not be surprised if they are already working on how to tune the HHR SS and the SS/TC already. My guess though is all the kinks still wont be worked out a while after the ss/tc comes out so we will just have to wait.

REIGN SS

but, with the GXP already having the motor, we should be one step ahead of where we were when the LSJ came out

Spectral

true and maybe im just dumb but isnt it going to be slightly different since its fwd vs. rwd?

REIGN SS

yes, there will be differences, but the biggest thing will be learning how to tune the 600+ parameters for the fuel management

Spectral

haha yah so lets hope thats all done and just the fwd vs rwd is all thats left.

stryder

great info most people looking to just drop their SC for the TC should read this. I want the TC but after reading this I am comfortable waiting for a year or so to get one.

brentil

The issue has to do with the complexity of the Bosh controller along with the added complexity of learning to tune a DI engine. Most common practices don't necessarily apply to DI engines. They've got a beta release for their HPTuners suite you can get and use on the Solstice GXP/Sky Redline but the software is very limited. A lot of needed features for the engine just haven't been unlocked yet. They're making progress though and I'm pretty sure they'll have it done by the time the Cobalt SS/TC hits.

I'm really hoping GM releases a Stage kit soon for the Solstice GXP. I could easily see a simple official tune putting the car at 290~300 HP with well over 300+ ft-lbs of torque. The injectors and pretty much everything else can handle it so it would probably be a pretty simple and cheap upgrade.

94firebird

do we have a price yet......any ball park figures that have been thrown out there?

WopOnTour

brentil, you'll have to explain to me what HP Tuners cannot do with respect to tuning the LNF engine...

Sounds like to me that you've never used it.
A lot of people just dont understand HP Tuner and how their table templates work. Seemingly "missing" adjustment parameters doesnt neccessarily mean it's something that's incomplete, just something not used by THAT particular ECM/PCM/VCM.But the table remains merely as a "placeholder" within the software (Pretty obvious when you see suspiciously absent control features for a turbo or supercharger on a naturally aspirated car, for instance)

Many people that have commented that HPT 2.2.0 is "immature" or "limited" with respect to the LNF are basing that on HPT experience with other GM (usually Delphi) modules, but because of the Bosch ECU used with the LNF, it just does a number of things differently - that's all. As you already alluded, peak boost levels for instance are adjusted in a very different fashion than the LSJ. Plus HP Tuner can control all aspects of the VVT cam timing via 16 3D tables as well as no fewer than 5 different ignition timing maps that also take into account existing cam angle. There's full MAF scaling, rev and speed limiter adjustments, Lambda based Power Enrichment, as well as the ability to remap ALL DTCs as Type A thru D (masked) when those pesky DTCs crop up when tuning beyond typical diagnsotic range/scaling.Sure, there are a couple of seemingly "mislabeled" TQ managment tables/values but once you start tuning a live car, you'd figure that out soon enough...

Trust me, most ANYONE fully versed in HP Tuners will be able get similar if not superior results to the BSR and other "canned" LNF tunes

And once they hammer out the final details on the transmission controls, the automatic transmission'd cars are gonna SCREAM!
YOU can use whatever you want for tuning of course, but for the $$ HPT is by far the most complete and cost effective LNF tuning solution that currently exits. The only package that really rivals it is Bosch's own ETAS INCA software (used for calibrating/tuning many of the Bosch ECU famililies including those used in professional motorsports) costing many thousands of dollars.

JMO
Regards
WopOnTour

brentil

HPTuners posted on the Solsticeforum stating themselves that their release for the LNF is in BETA and not final for the LNF. He was giving various members access who have had a lot of experience with their software to the beta and they've reported not having full access to control all features of the LNF yet as well. So unless they've released the final code and haven't mentioned it then I'm going to go off what they last told us.

BSR had full access early on because someone at Bosch leaked the code to them. Everyone else has had to do it the normal way.

WopOnTour

That's possible I guess depending on WHEN this discussion took place. The LNF began to be supported on the 2.19 Beta version and was released officially with the current 2.20 full release on Sept 26 2007. The calibration tools in 3rd party software like this are always a "work in progress" of course, but to state that the HP Tuner in not able to tune full range fuel, spark and boost (plus a lot more) on the LNF is incorrect. Sure there maybe things they plan to add, but that's always the case, depending on how they are able to focus their development process. They just finished "real-time" tuning on some of the V8s so theres a chance live tuning might become available in the 4&6cyl models in the near future.

Wop

OniMirage

at this rate it won't be until 2009 till everything is stable enough for an sc owner to jump to a tc. I woudn't wanna go through another set of years before things leveled out. First year with the balt nothing second year finally some decent upgrades 3rd year things are great ... then it was dropped. At least that gives time to save money.

MaJ

You're making a pretty bold statement here, concidering you don't know anything about the majority of people who drive SS/SC's.... I personaly am not struggling to pay for mine, and had mods in it within 3 months.

I don't think it will be long at all before people start doing things to these cars.

OniMirage

Your kidding me right? I bought the cobalt the first ******* year it came out there was NOTHING for this car that was quality enough to use. torque dampeners twisted, intakes had fit issues, mounts didn't help wheel hop, piggyback systems caused drivability issues. Going into the second year there were stage kits, decent intakes that corrected fit issues, some mods caused cels or limp mode, HPT made a great appearance and helped alot, GM's own kits had an update to correct drivability issues. Going into the 3rd now and there are lots of good mods and upgrades and the market has matured enough that people can mod how they want the car to be.

I still say 2009 is when people will consider the tc as a trade in for the sc since there is nothing out for the car right now and its still months away from even being released.

So before you start saying I don't know **** about people that own the cobalt how about looking at the join date of the person your talking to.

Blown 4-banger

PWN3D!!!