4GS7

Okay, so this new engine is loaded with tech that most of us aren't very familiar with. Of note are the VVT (cam phasing), AFM, and Direct Injection. That stuff won't interfere too much with bolt ons, but will be of great concern for those of us who want to do a cam.

Assuming that the fine folks at EFILive and HP Tuners will be hard at work immediately cracking the PCM....


How difficult will it be to make old school tricks (quick and dirty cam swap) work on this new school motor? There is a wealth of information out there now. My concerns, and I welcome any educated thoughts on the matter, are as follows.

AFM - Displacement on demand seems like it would be have to be deleted if you wanted to put a cam in the car. I know people are doing that with automatic Camaros already, but that's because the parts already exist to convert those to LS3s.

VVT - Have any tuners figured out how to use that to our advantage? Is it possible to actually make more power utilizing the VVT with an aftermarket cam? How difficult will that be to tune? Will most people just dump the system entirely and tune the cars like they're LSxs?

DI - This probably won't be a concern for NA folks, but for those of you, and I'm sure there are many, who want to bolt a blower to the car immediately, will the factory DI setup be sufficient?

Discuss.

Jasil

Aftermarket on hightech NA sucks!! Just look at what is being done in the BMW and Mercedes world right now 600rwhp+ with bolt ons, but those are FI engines. Trying to tweak and DI, VVT, N/A car is a case of chasing diminishing returns imo.

I think the new engines unless they come with FI will be the least aftermarket friendly ever!!

CPhelps

Responses in bold.

One additional thing that may be worth discussing is that according to "BiggGunz" on LS1Tech, the E92 ECM will be smart enough to compensate for bolt on mods, and is even capable of learning the profile of a cam (presumably nothing too wild). Now whether you believe that or not probably goes back to whether or not you think he's trolling, or actually a GM combustion engineer as he claims. I do know the stage kit for the LNF DI turbo engines did unlock a "learn mode" that was supposed to compensate for additional mods, so there is some precedent at least for GM ECUs being able to do this. I know your original assumption was that tuning was available, but if the ECU can respond to take advantage of bolt on mods, and even some more advanced things like camshaft swaps, that will definitely be an interesting twist on the mod scene!

SBC_and_a_stick

It may the LT1 is way easier to tune for mild and medium power increases. That new ECU is said to adapt to just about anything, even cam regrinds. If a trip to the dyno and computer upgrades are not needed it should be easier than ever. Basically, the tuning costs are waved.

Once you exceed the capabilities of the stock ECU I think you have to fork over massive amount of $$ to make the additional HP. But even then, the fuel system is so overbuilt it will never need upgrades.

*edit: CPhelps beat me to it.

CPhelps

This got me thinking, in one of the LT1 articles I read that the VVT system now had 62 degrees of command vs. 52 of the Gen IV stuff, and that it could actually use it all. Apparently the Gen IV engines went to unstable combustion if they attempted to vary that whole range. I thought that was an interesting tid bit, and seems like the Gen V VVT would be a lot more effective than Gen IV if it can stably use all of its cam phase range. The higher ratio rockers should also allow higher effective lift. My understanding was that on the Gen IV engines the VVT system limited overall lift - part of why the L99 made less power than the LS3.

4GS7

Very good info. Thanks.

briannutter1

Heads can be ported. There is a good chance that the aftermarket crank forgings used for the gen4 can be used for the gen 5, so the 427/440/454ci stroker/sleeved shortblocks will happen pretty quickly. The rods don't appear to have changed much with plenty of aftermarket options. Pistons are easy as we've been developing DI pistons for over 8 years now. The Cam guys are pretty familiar now with opening and closing points and behavior, so you can expect the tuners to learn cam phasing pretty quickly. The Soltice GXP tuners are the most knowledgeable about pulsewidth opening and closing points to get the fueling right for the other modifications. Racers who want to play while the tuners are catching up have the option of a sheetmetal manifold with conventional injection. Guaranteed that Hot rod magazine will plop a Holley carb on one and do a dynotest within 6 months of the cars release The first guy that sends me an engine to do parts development on will get a good deal on a 427 shortblock.

phils C5 vette

I can talk about most of this based on the camaro platform.

AFM/DoD- The Automatic camaro owners like the aftermarket calibration because of the AFM/DoD. Its not as evident with stock mufflers, but when guys change to aftermarket mufflers, they hate the drone when it drops to 4 cylinder. Just like the current 6l60/80/90 transmission, it will meet the needs of the masses, but many owners feel it shifts slow and soft. Once calibrated, I love the automatics.

VVT- Im not a fan of it when it comes to modifications on the engine side and most guys do a LS3 conversions.

The aftermarket VVT cams are ok, but have less lift, and cam phasing isnt a factor once you get the hang of the effects in timing.

The direct injection also shouldnt be a factor. It can only help the engine be more effective.

Phil

obzidian

True.

Don't necessarily disagree with you but I would like to point out that according to CPhelps post, the LT1 will have more lift, more "resolution" per turn and will in fact flow more (and perhaps more efficient) than the L99. I don't see how GM dedicated all that man power to a new engine and not improve on the previous platforms.

One thing that I did like about the L99 was the torque it had in the low range so it is no surprise then that the marketing for the LT1 shows an increase in the low range.

WHT

Besides, if you even look at this engine cross-eyed, GM will know it. Get ready for the future. This won't have your father's PCM.

Suns_PSD

I dig that so many around here enjoy the heavy modifications on their Vettes. But I wasted tens of thousands on a diesel truck. It never ran that well afterwards, it always broke parts, it was loud, and when I sold it I maybe got $5K extra for apprixamately $40-50K in mods.

My current car got a few high quality bolt ons, and right when I had a deposit on a turbo kit and full engine internals and was about to go completely nuts, I remembered my truck and decided to instead just purchase a MUCH faster car, which is what lead me to Corvettes.

I guess what I'm saying is that the laws of diminishing returns really apply when you begin modifying.

Any modern car should get some nice bolt ons and call it good imo.

Bmorevette

While reading this thread this was all I thought about. As soon as you mod something there is no hiding it. Especially if it adjusts itself to new parts by learning on it's own.

4GS7

That's nice for you, but I don't do it for financial ROI. I do it for emotional and physical ROI. Anyone who gets into this game knows they're not going to get their money back when they go to sell.

JoesC5

If the ECM can automatically adjust for some mods, wouldn't that take away some of the financial incentive to hack the code, as there will be less people that will want to perform mods outside of the parameters that the stock ECM can handle?

jsnolan

Why are you so worried about getting your money out of it, does your car sit in the living room or do you drive it? Got a nice cam, Kooks headers and X-pipe, under drive pully, 3200 stall, and have driven from NC to Ma 4 times in the last year. Also put it down the 1/4 mile over 100 times.
I bought the car to drive, not as a piece of art to hang in the garage.
(although it is a masterpiece)

Not only will it self-adjust, but the next time yo pull into McDonald's for a cup of coffee, the free Wi-Fi will transmit to GM all that has happened to the car since the last time.

cv67

If you have to truly worry about ROI maybe its not for you.
Its a car.....a toy at the end of the day

JerriVette

I agree and it has nothing to do with ROI.

It has to do with the reliability and hassle free ownership.

I've done the modding thing over the past 35 years and over the years I ve had a few laughs and at the same time when the mileage added up and the hassles did as well...I remembered your motto ringing in my head..(at the time it was either good friends words or my own in the past...)

To each there own but in my opinion...nothing as good long term as factory hp and high performance from corvette.

BeaZt

What's wrong with GM knowing if you mod the car? Why on earth would you want them to warranty your mods? When I mod I know my warranty is gone, that's a fact I accept knowing the consequences.

BLACKVETTE102

You guys know that the E92 ECU has already been put into several platforms. I used to own a big turbo modded Cobalt SS with the E92. And it was the exact opposite of adaptable. It was a nightmare to work with and tune. It was also very tempermental and would mess up without tuning after every mod. It wouldn't even come close to adapting to mods it would just reject it. On top of that HPT only could partially hack the code because it was so complicated. Also I learned with the cobalt that the problem with the fueling that kills you is the amount of pulse width your injector can fire. If I remember correctly you could only inject the fuel in a 5-7 millisecond window on the compression stroke. So even though you had injectors that could mathamatically flow alot of fuel on a port injected motor where you have a longer injection window it didn't work out to the same fueling capability. On the cobalts you jacked up the pressure as high as you could and then you had to look at secondary fuel systems. As far as AFM it will need to be deleted with a lifter change if you want to run any semi serious cam. And the bigger the cam the more you will have to limit VVT, eventually it will need to be deleted if you go big enough.

briannutter1

You hit the nail on the head with this. The guys with LNF experience are the ones that are going to do well with the Vette. Luckily the experience can translate to this engine and get it on track quicker than otherwise. On the plus side, the piston can be designed to accomodate a longer pulsewidth. The valve pockets can be deepened to accomodate longer duration cams and phase angles.