Pictures of 2014 Stingray

[pmkls1]

Yes, lean cruise can be taken pretty far because the injector timing can be altered which greatly reduces the risk of detonation. The pistons that I have seen do have a strategically located and shaped recess that serves as a mini combustion chamber. It is very similar in concept to the pre-combustion chambers used in some diesels. These features also allow for even higher compression ratios without the increased tendency to detonate. I am also wanting to think that piston squirters were a feature on the 3.6 high-feature v6 and it's other variants. I'll see if I can verify that info later. Anyway, I do have a "teaser" pic that I can share that is a pic of a direct injected v6. If you look real closely you can see a couple witness marks on the outer edges of the dome (yeah that's right I said dome) from the intake valves making contact. This thing saw 20k mile intervals on regular old conventional oil because that's what the oil life monitor said and believe it or not GM says that's perfectly fine. This is the result of going by the "approved" maintenance schedule which was new cylinder heads and timing chains all before 100k miles.


2012-04-09_17-31-47_655.jpg

[EagleMark]

No, just one regular combustion chamber. EDIT: Well maybe there was piston chamber stuff not mentioned?

Well the oil spray would help keep the piston cool, most get cooled by oil from wrist pin anyway, piston is what get's hot in lean cruise! But oil could still get hot after awhile.

The theory I described was more physics, the Air/Fuel mixture was cool entering a hot combustion area, never touches piston or cylinder walls, explodes mid air, like a barrier. There was also some mention of double fire, one during compression and one at or just after TDC...... wish I could find the article......... wish I could find the article...

[pmkls1]

Here is a pic of the rear that I lifted from Chevy's website. I just can't make myself like it. The rest of the car is slick but the back end is a disappointment to me still.

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[EagleMark]

I'm still patial to square body Chevy trucks... but I still think it's sweet looking...

[pmkls1]

What I meant about the impression being like a mini combustion chamber actually has to do with getting the fuel mix to light off and burn properly. That was one of the problems that GM ran into during development. It evidently took a lot of trial and error to get the size, shape, depth, and location of the little "trough" on the piston just right. EDIT: After re-reading my reply I see that I sort of mixed different points all together by accident. The features that allow for more compression are direct injection and injector timing. I apologize for the confusing jumble there.

[pmkls1]

Since the piston squirter question was eating at me until I could confirm it and I'm now locked out of GM's system I googled the high feature v6. I don't think I can go a few hours without google sometimes lol. Anyway, it led me to a wikipedia page that after reading appears to be pretty accurate. There are a couple of small details that I'm a little unsure about like I've never seen one with vvt on the exhaust only, but overall it's dead on with the major facts. I'm gonna add a link below just because you can see the increased compression ratios and power output of the direct injected versions. The piston squirters are mentioned as a capability, but I'm still thinking that all of the north american versions were equipped or at the very least the direct injected ones are.

http://en.wikipedia.org/wiki/GM_High_Feature_engine

[JeepsAndGuns]

A fair share of the direct injection engines that i saw cutaways of,have oil spray nozzles pointed to the bottom of the pistons.

I thought the LS engine (or atleast some of them) already had those? It seems I remember seeing a buildup of one somewhere (either on tv or online) and I remember the oil squirters and thought it was interesting.

[pmkls1]

I thought the LS engine (or atleast some of them) already had those? It seems I remember seeing a buildup of one somewhere (either on tv or online) and I remember the oil squirters and thought it was interesting.

On the LS platforms the only engines that have piston squirters are the LSA & LS9. From what I understand all GenIV blocks have a boss that can be machined for the squirters as well as the LSX blocks.

[one92rs]

oil squirters are to keep the pistons cool. leave a squirter out of a 3406 cat engine and you can kiss it goodbye after a short time. ls9 is supercharged with higher compression in which the piston would benefit from having squirters. the precombustion chambers are bfor mixture of fuel and to keep it centralized to not spread it that would just cause a hot burn. direct injection is in most diesels and work great. its about darn time someone put it together in a new performance gm.

[pmkls1]

The use of piston squirters in direct injected engines is to cool the pistons because of the lean mixtures used under certain conditions. I don't remember the reason, but I believe that oil squirters have been in use on the high feature V6 prior to the direct injected models. I was also thinking that the LS7 had squirters, but have not been able to verify that yet. Something that was quite a rarity was having to perform any kind of repairs on the bottom end of the high feature V6 engines or the LS7. GM has been a little slow to adopt "newer" technologies to any of it's performance engines. They have been making flex-fuel vehicles for years now, but still they don't offer the capability on the corvettes and camaros.

[EagleMark]

They have been making flex-fuel vehicles for years now, but still they don't offer the capability on the corvettes and camaros.

Thank God!

[Six_Shooter]

The "High Feature V6", the 3500 used a single piston squirter for the 5 and 6 cylinders. It looks like the squirters can be added to the other 4 cylinders and is why I have some just for that very reason. ;)

[pmkls1]

I know that you aren't a big fan ethanol Mark, but you do realize that in an engine like the LS3, LS7, LSA, LS9 or the "new" LT1 running E85 would help to coax a few more ponies out of them ? A perfect example of how E85 can improve a sports car's performance would be the Koenigsegg CCXR. It is a flex-fuel capable supercar and quite a monster making a stout 806hp on gas, but puts out a whopping 1018hp on E85. That is a massive 212hp increase just by filling up at a different pump. Granted the CCXR is twin turbocharged, but higher performance N/A engines do make more power with E85 too. Most of the issues that plague E10 aren't a concern with E85 and corrosion isn't a concern because these vehicles are designed to be compatible with alcohol. Since there is 70-85% alcohol it would take a boatload of water to ruin the fuel and I don't think that phase separation is a problem due to the small amount of gas and/or other chemicals that make up the remaining 15-30% of the fuel.

[pmkls1]

The "High Feature V6", the 3500 used a single piston squirter for the 5 and 6 cylinders. It looks like the squirters can be added to the other 4 cylinders and is why I have some just for that very reason. ;)

The 3500 V6 is in the high-value V6 line. The high-value V6 line is just the latest version of the long-lived 60 degree V6 platform that debuted in the '80's. With the exception of the twin-cam 3.4 used in W-bodies in the '90's all of the other versions were a typical pushrod layout with 12 valves. There was of course the twin-cam 3500 V6 that was only around for a couple years that was based on the Northstar, but they are pretty rare. The high-feature V6 debuted in 2004 in the Cadillac CTS, and while it is also a 60 degree engine it shares nothing with the old chevy 60 degree V6. The high-feature V6 is an all aluminum 24 valve double overhead cam design with variable valve timing. The most common displacement is 3.6 liters, but there are 2.8, 3.0, 3.2 versions out there. The piston pictured above in one of my posts is a direct injected 3.6 piston. Direct injection was also something that never made it to the high-value line.

[JeepsAndGuns]

the Koenigsegg CCXR

Dream car! *drool*