3.6 liter High Feature I a Fiero (Page 8/15)
dobey SEP 19, 01:53 PM

quote
Originally posted by 2.5:

Is there a reason its called "High Feature"?




It is the name ascribed by GM. Other engine families also have similar naming:

Cadillac 4.1/4.5/4.9 - High Technology engine
3500/3900 V6 - High Value engine

I presume the "High Feature" name was given as the design allowed for a greater (high) number of features to be implemented in the platform over the years, without significant changes to the overall design of the engine itself.
qwikgta NOV 15, 08:05 PM
so this is an old tread, but i want to bring back the discussion of the high feature 3.6 in a Fiero. I have a chance to grab one w/ 6 speed AT for a daily driver. Has anyone figured out the tuning?

Rob
mender NOV 15, 08:17 PM
Try Overkill as I mentioned on page 1. I still haven't finished my swap so no confirmation on his tuning but I had enough faith to pay him for it.
Joseph Upson NOV 16, 03:59 PM

quote
Originally posted by qwikgta:

so this is an old tread, but i want to bring back the discussion of the high feature 3.6 in a Fiero. I have a chance to grab one w/ 6 speed AT for a daily driver. Has anyone figured out the tuning?

Rob



I have since acquired that 2008 Cadillac CTS SIDI I mentioned above some time ago. I love the car, but, the associated electronics is no joke. Unless you are able to source a stand alone PCM modification, and or have unlimited time to graft such a complex system into a Fiero, my advice to you is don't even think about it. My statement of building a 3.6L for its intended platform was wisdom in ways I was not aware of.

The High feature V6 also equals high maintenance potential, especially the SIDI version. If you remove the fuel injectors from he SIDI motor that's an automatic ~$200 in non reusable parts that must be replaced; pressure sensor, all injector seals one of which requires a special tool to install and two fuel pipes as a result of the danger the high rail pressure poses in the event of a high pressure leak. Idle pressure is around 500 psi and it goes up from there.

If you find you must install the BCM, that's another monster who's size depends on the application in regards to on board features as it will put the system in limp mode if it doesn't see certain modules functioning properly and HPtuners may not be able to access/address the necessary parameters to get around it. In addition to that, the programming in the Bosch PCM used from ~07 to 2012 where GM switched to a Delphi PCM and system, is a headache to tune and some reported even dangerous as the programming is complicated with interlinking tables where a seemingly harmless entry in moderation through HP Tuners can lead to an exaggerated response, like not releasing the throttle when you take your foot off the accelerator (remember Toyota and their problem similar to this). That's from someone who was experimenting with tuning so the 2012 and up PCM is the way to go as it is said by experienced tuners to be fairly straight forward unlike the earlier Bosch system. Otherwise, baby, baby-steps with the Bosch.

As for the VVT, It's often not said if ever, but I'm pretty sure it plays a part in the ability to run regular unleaded with a compression ratio greater than 11:1 in addition to EGR effects at least in the DOHC motors. For starters, the intake valve does not open until 14 degrees after top dead center which effectively lowers cylinder filling efficiency potential vs. if it opened at 4 deg before TDC. That effectively counters a high compression ratio. At cold start the engine runs about 1600 rpm and the intake camshafts are commanded to about 15 deg advance. Once warm up is complete both intake and exhaust cams settle down to 0 deg. You can actually hear the change in exhaust tone outside the car as it happens. Intake cams are only capable of advancing and exhaust retarding from their parked positions.

I suspect the programming uses a combination of camshaft position and spark timing to control spark knock for dynamic performance as either can be advanced in small increments gradually to achieve the maximum potential that a given fuel octane can sustain. In other words, premium fuel = premium power.

One thing I would turn off in the car if I could is traction control which seems overly sensitive. I dropped the rear tire off the curb cutting it a bit sharp leaving the fuel station and immediately power was cut briefly. I hit a small bump in the road during a turn at about 25 mph and again power was cut briefly, it didn't take much, just the little thump felt in the car was enough. There are sensors all over the place and I believe the above incidents were in conjunction with the steering column sensor which probably increased sensitivity because the car was in the middle of a turn where there would be an increased possibility of spinning out although that wasn't the case.

Plug and play is over. Now it's plug and plug and plug, keep plugging, etc... The most basic optioned donor system will likely offer the least amount of trouble if that term can even be used here. If someone sponsored me to complete such a swap in a Fiero for myself I wouldn't do it.

Good luck to anyone willing to try. Do your homework before you spend a penny as these motors are very sensitive to some changes and some stock parts although they will fit across different 3.6L applications, they may not result in satisfactory performance when paired with a PCM that was not programmed to use them, camshafts, high pressure pumps and injectors for example not to mention the different intake and cylinder head designs.

[This message has been edited by Joseph Upson (edited 11-16-2017).]

mender NOV 16, 05:35 PM
As Joseph said, use the E39 based engine (LFX) and stay away from the Bosch. I think the six speed auto only came with the LFX so you might be good but check anyway.

[This message has been edited by mender (edited 11-16-2017).]

Daryl M NOV 18, 11:54 PM
Rob, I contacted Overkill about LFX programming. Said that if I went with a manual tranny, he would program an E39 ecm as a stand alone unit with a 2012 Camaro tune. He discouraged going with an automatic. He said it would require the ECM, BCM, and transmission module to all be programmed and used, but he was unsure if he could make it all work.
Daryl M
qwikgta NOV 25, 11:32 PM
Damn shame, there are three of them at my local pick n pull and its half off weekend. Motor/trans and everything would be about $300 - $400 bucks.

Rob
Daryl M NOV 26, 09:25 PM
Rob, Pick up an LFX with the ECM and gas pedal for half price, then find a Saab Aero F40. If you drive an automatic, the muscles in your left leg will atrafee.
Raydar NOV 28, 07:26 PM

quote
Originally posted by mender:

As Joseph said, use the E39 based engine (LFX) and stay away from the Bosch. I think the six speed auto only came with the LFX so you might be good but check anyway.




The LFX also came in the Camaro, with a manual.
I was going to try to copy the VDF file from a friend of mine (has a 2012 LFX / manual) but it was "tuned and locked." I would have been perfectly fine with a stock VDF.

[This message has been edited by Raydar (edited 11-28-2017).]

mender NOV 29, 03:17 PM
I was meaning that if it had a six speed auto on it, it was an LFX and not an LLT.

I have a Camaro 6 speed manual buried in my shop somewhere ...