: Am I the only one???



PSRmark
07-28-09, 04:54 PM
That is throwing caution to the wind when it comes to severly over boosting these cts-v's? Now I understand that I am part of D3 and a supporting vendor, but I come in here to show my concerns for this motors longevity with adding almost 7 more lbs of boost to an already lacking piston choice. Hell, D3's pulley upgrade is only putting an extra 3 psi to it and I am barely comfortable with that. I've done my homework so I already know that the new Hyperjunk pistons are far more advanced than they used to be but they are nowhere near as strong as a good quality forged unit...why do you think they opted for the forged units for the ZR1?

So am I the only one that thinks getting over 100k out of this motor with the brittle pistons and 15psi will be an issue? :hide:

qictrk
07-28-09, 05:57 PM
Thanks Mark for bringing me back from the brink. Your right, i've gone down this road before and first i blew a piston and then after that was fixed, i blew the tranny. This was with another vehicle, years ago, but here i go again. I will stay at my 12 lbs of boost and hold the line there. There is no end to hp but it is a tough addition to give up. Cecil...........:worship:

whisler151
07-28-09, 06:00 PM
Thanks Mark for bringing me back from the brink. Your right, i've gone down this road before and first i blew a piston and then after that was fixed, i blew the tranny. This was with another vehicle, years ago, but here i go again. I will stay at my 12 lbs of boost and hold the line there. There is no end to hp but it is a tough addition to give up. Cecil...........:worship:

Nice, how much power are you making with the pulley?

Luna.
07-28-09, 10:47 PM
That is throwing caution to the wind when it comes to severly over boosting these cts-v's? Now I understand that I am part of D3 and a supporting vendor, but I come in here to show my concerns for this motors longevity with adding almost 7 more lbs of boost to an already lacking piston choice. Hell, D3's pulley upgrade is only putting an extra 3 psi to it and I am barely comfortable with that. I've done my homework so I already know that the new Hyperjunk pistons are far more advanced than they used to be but they are nowhere near as strong as a good quality forged unit...why do you think they opted for the forged units for the ZR1?

So am I the only one that thinks getting over 100k out of this motor with the brittle pistons and 15psi will be an issue? :hide:

100% my thoughts as well...

So, to answer your question, NO, you are not alone...

I'm still waiting, however, for (cough) someone to come out with a forged piston solution though... :halo:

CVP33
07-28-09, 10:55 PM
Can't you tune the car to run with this boost? Retard timing, etc? My SRT8 is 10.5/1 CR stock. I'm now Procharged with 5-6psi on a non-forged motor and seeing very little knock retard, very good a/f ratios and the thing runs under 200* with the air on full tilt and 95* outside. The V is 9.0/1 CR is the additional boost putting that much stress on the motor?

For the record the SRT8's have crappy cast pistons with a top ring setup that's not really ideal for running boost. But all of the engine failures so far under boost have been due to poor tuning and detonation. If you can keep detonation from happening and keep the motor running cool, what would be the next enemy of longevity?

Gary Wells
07-28-09, 11:05 PM
.........................If you can keep detonation from happening and keep the motor running cool, what would be the next enemy of longevity?

your foot.

SlvrBullIT
07-29-09, 02:15 AM
^
lmao!!!

Gotham CTS-V
07-29-09, 07:45 AM
I used to frequent the Corvette forums and I would always read reviews and threads from people with LS3 Vettes that were supercharged but the internals on the motor weren't touched. These guys were running 650rwhp+ and saw no problems. I'm sure they are still on the forums and I bet we can learn a lot from their mods since the LSA is basically the LS3.

I feel safe having another 100rwhp over the stock setup. Don't see anything wrong with upping the boost just a little on a stock car that GM would warranty for 5 years. Would I push it to the next level of 150-200rwhp over stock? Would I use a nitrous kit on an already boosted motor? Nope.

I am thinking that maybe a Meth kit would be a good addition though for safety and some extra power.

Gary Wells
07-29-09, 07:55 AM
A methanol injection unit should not bring you any substantial increase in HP or TQ unless you are running into a detonation problem, and that could be experimented with by adding a few gals of 100 octane unleaded and see if your car runs any better or not. Might get a few ponies from it's cooling of the intake charge, but that's about it. If you're seriously interested in this, might want to talk to Julio Don at "AlkyControl.com" and see if he would be interested in building a kit for a '09 CTS-V. Julio also has a forum on his site.
>www.alkycontrol.com<

CIWS
07-29-09, 08:00 AM
The question comes in though about longevity. How long will the stock motor's parts last if boosted at higher levels. Most folks like "more now" and are not really thinking will this cause the motor to crap two years from now. Some may not care if they get two years service and then it poops, thinking they can somehow restore to stock and sneak it past a dealership's warranty service. Honestly right now it's going to become a testing game as new owners mod their cars to certain levels and after some measure of time we get to see how they're holding up.

Gary Wells
07-29-09, 08:09 AM
Guaranteed it won't be lasting any longer. I am sure that down the road we will be hearing of some intermediate & long range effects, good or bad, and probably the latter.

CIWS
07-29-09, 08:31 AM
The logic side of me has to ask the question of why GM would develop the LSA and the LS9 if the LSA build was capable of handling the HP with no longevity problems. The difference in the motors is only roughly 80 flywheel HP and we have owners now who have modded their cars to this level. If the LSA could handle those power levels with no real issues there would have been no need to spend the extra money in building the LS9.

haterinc
07-29-09, 09:11 AM
in my experience, the motor will be fine based on the similar set up... the auto chick with a dick (the auto tranny lol) will be the weak link in regard to wear and tear i'm guessing...

Florian
07-29-09, 10:07 AM
the tranny should be bulletproof. Your pistons are the weak link, then your half shafts. F/I motors are great to run, but tough to mod as there are more variables in the equation to deal with. You will need to re-do the internals on your motor to instill confidence and allow for much more than 600rwhp
Do your homework.

F

Ready2roll
07-29-09, 10:17 AM
I used to frequent the Corvette forums and I would always read reviews and threads from people with LS3 Vettes that were supercharged but the internals on the motor weren't touched. These guys were running 650rwhp+ and saw no problems. I'm sure they are still on the forums and I bet we can learn a lot from their mods since the LSA is basically the LS3.



I'm one of those guys (69 Vette on CF forum)
I'm running 735 RWHP on my C6Z with the stock cast pistons. I beat this car to death and no problems. It's all in the tune ;)

Gotham CTS-V
07-29-09, 10:49 AM
I'm one of those guys (69 Vette on CF forum)
I'm running 735 RWHP on my C6Z with the stock cast pistons. I beat this car to death and no problems. It's all in the tune ;)

The LS7 motor is even worse for boost than the LS3. That's good news man. I used to also have an LS7 that was running 650rwhp.

Torxila
07-29-09, 11:12 AM
The benefits of an ALKY injection system on these "V" cars is minimal compared to their use on Centrifugal supercharged or Turbo'd LSx engines where the alky is injected after boost & inter-cooling has occurred. Injecting the alky, pre the charge will drop temps a bit, but most gains will be lost as it then gets heated up in the blower.

The CF forum group (C5&C6) have MANY stock internal(s) engines running 600+rwhp cars (some with Julio's/ECS kits) some without.

I've had 2 TT 'vettes, both have used the Julio/ECS kits with great success.

Maybe a direct injection alky setup needs to be developed for these beasts.

Regards,
George

Gotham CTS-V
07-29-09, 11:45 AM
The benefits of an ALKY injection system on these "V" cars is minimal compared to their use on Centrifugal supercharged or Turbo'd LSx engines where the alky is injected after boost & inter-cooling has occurred. Injecting the alky, pre the charge will drop temps a bit, but most gains will be lost as it then gets heated up in the blower.

The CF forum group (C5&C6) have MANY stock internal(s) engines running 600+rwhp cars (some with Julio's/ECS kits) some without.

I've had 2 TT 'vettes, both have used the Julio/ECS kits with great success.

Maybe a direct injection alky setup needs to be developed for these beasts.

Regards,
George

Thanks for your experienced knowledge bro.

Ready2roll
07-29-09, 12:13 PM
The LS7 motor is even worse for boost than the LS3.

that is what they say but it's just a myth! Plenty of us running stock bottom end LS7's above 700 RWHP. :thumbsup:

PSRmark
07-29-09, 12:23 PM
I used to frequent the Corvette forums and I would always read reviews and threads from people with LS3 Vettes that were supercharged but the internals on the motor weren't touched. These guys were running 650rwhp+ and saw no problems. I'm sure they are still on the forums and I bet we can learn a lot from their mods since the LSA is basically the LS3.

I feel safe having another 100rwhp over the stock setup. Don't see anything wrong with upping the boost just a little on a stock car that GM would warranty for 5 years. Would I push it to the next level of 150-200rwhp over stock? Would I use a nitrous kit on an already boosted motor? Nope.

I am thinking that maybe a Meth kit would be a good addition though for safety and some extra power.


I have seen some of these vettes and most of them have lived and some have not...the ones that didnt live were not always due to a bad tune. I've seen these come apart for different reasons, wether it be a ring land on the piston or a connecting rod failing the issue is that it is ALWAYS a gamble.

It's not that i'm saying dont mod the cars cause thats what i love to do most, im just expressing my concern to those who want to get greedy.

We do plan to add Meth to one of these next week, it should help with the intake air charge temps...I've noticed at about 130 IAT2 the power on these cars start to drop, after that we will throw in our heat exchanger and test that with the meth and larger crank pulley and make multiple passes to try and keep under that 130 threshold.

PSRmark
07-29-09, 12:27 PM
The question comes in though about longevity. How long will the stock motor's parts last if boosted at higher levels. Most folks like "more now" and are not really thinking will this cause the motor to crap two years from now. Some may not care if they get two years service and then it poops, thinking they can somehow restore to stock and sneak it past a dealership's warranty service. Honestly right now it's going to become a testing game as new owners mod their cars to certain levels and after some measure of time we get to see how they're holding up.


The logic side of me has to ask the question of why GM would develop the LSA and the LS9 if the LSA build was capable of handling the HP with no longevity problems. The difference in the motors is only roughly 80 flywheel HP and we have owners now who have modded their cars to this level. If the LSA could handle those power levels with no real issues there would have been no need to spend the extra money in building the LS9.


Those are both good points and exactly what i'm trying to get at

Luna.
07-29-09, 12:32 PM
I have seen some of these vettes and most of them have lived and some have not...the ones that didnt live were not always due to a bad tune. I've seen these come apart for different reasons, wether it be a ring land on the piston or a connecting rod failing the issue is that it is ALWAYS a gamble.



You can add an '05 CTS-V with maggie to that list as well...I've seen it happen (this was flat out piston failure).

I certainly hope that no one has a failure at all, for that is only a bad thing and reflects negatively on the CTS-V community as a whole.

But for those of you who throw caution to the wind, good luck is all I can say.

Further, I would also hope that the idea doesn't spread about how the motor/car sucks if a failure does take place. I would think that a good reply would be, "Yeah, my motor failed, but I pushed the sh*t out of it, so don't necessarily blame GM..."

(Well, blaming GM for installing the weak-a$$ pistons to begin with is fair, for that's simply moronic, but there's a difference between that and pushing it to 15psi and still crying foul...just about every regular on this forum knows well the pistons are the weak link in the entire drivetrain...)

Think about it---if propanganda was out there about how the LSA motor was, "weak," that hurts all of us...

1BlinkGone
07-29-09, 02:59 PM
To me, it's all about paying attention to what the parts & package are spec'd for, and knowing there is some, but limited cushion in pushing the envelope.
The adage 'the right tool for the right job' applies here too.

I would not condemn the CTS-V engine as weak due to its pistons... after all, they were chosen to perform within a predetermined spec by the mfg. Ya wanna go beyond that, you have to sensibly explore other options.

So, for example- ya try to use a screwdriver as a prybar, and it breaks. No it's not weak; you abused the tool by misusing it outside of its intended parameters. Same with increasing boost past a certain point using the oem pistons.

Short-Throw
07-29-09, 04:57 PM
The question comes in though about longevity. How long will the stock motor's parts last if boosted at higher levels. Most folks like "more now" and are not really thinking will this cause the motor to crap two years from now. Some may not care if they get two years service and then it poops, thinking they can somehow restore to stock and sneak it past a dealership's warranty service.

CIWS, Exactly!

More HP is not free! Most seem to understand it, some don't.

From a vendor's view they have nothing to lose. They get paid regardless of any poor outcome. Now before you go accusing me of being anti-vendor, I'm not, far from it. Aside from my race cars, I modded my last 3 Corvettes way beyond factory specs. I love modding cars and some tuners do this very well, but most do not. Some will publicly or privately promote methods to deceive dealers with their supposed stealth tunes -- which FYI -- aren't that stealthy as marketed. How many people honestly feel that if GM could have delivered more HP safely for an incremental cost, they wouldn't have?




I feel safe having another 100rwhp over the stock setup. Don't see anything wrong with upping the boost just a little on a stock car that GM would warranty for 5 years.



The logic side of me has to ask the question of why GM would develop the LSA and the LS9 if the LSA build was capable of handling the HP with no longevity problems. The difference in the motors is only roughly 80 flywheel HP and we have owners now who have modded their cars to this level. If the LSA could handle those power levels with no real issues there would have been no need to spend the extra money in building the LS9.

As far as making changes to the LSA, here is the bottom line on what was needed in order to
maintain reliability to go from 556hp/551tq to 638hp/604tq:

LSA vs. LS9

LSA has hypereutectic pistons 9.09:1 compression ratio.
LS9 has forged 9.15:1 compression ratio.

LSA has Eaton TVS 1900 supercharger.
LS9 has Eaton TVS 2300 supercharger.
LS9 has 1mm larger diameter head bolts for increased clamp load

LSA has powder metal connecting rods.
LS9 has forged titanium connecting rods.

LSA has 8-bolt flywheel crank.
LS9 has 9-bolt flywheel crank. Both are forged.

LSA has solid valves.
LS9 has titanium intake and sodium filled exhaust valves.

LSA rev limit is 6200rpm.
LS9 rev limit is 6600rpm.
Cam specs are different between LSA and LS9.

Intercoolers are different (1 brick on LSA vs. 2 bricks on LS9), but that was done more for packaging.
Accessory drives are different, but again for packaging.






Mike

Short-Throw
07-29-09, 04:59 PM
To me, it's all about paying attention to what the parts & package are spec'd for, and knowing there is some, but limited cushion in pushing the envelope.
The adage 'the right tool for the right job' applies here too.

I would not condemn the CTS-V engine as weak due to its pistons... after all, they were chosen to perform within a predetermined spec by the mfg. Ya wanna go beyond that, you have to sensibly explore other options.

So, for example- ya try to use a screwdriver as a prybar, and it breaks. No it's not weak; you abused the tool by misusing it outside of its intended parameters. Same with increasing boost past a certain point using the oem pistons.


:yup:

CVP33
07-29-09, 05:19 PM
Agree with everything posted above. Most of our guys use Meth injection to keep the temp' in check. The enemy of the Chrysler motor is heat. Excessive heat causes our top ring to expand and lock into the cylinder, then all hell breaks loose. The failures, all heat and top ring related so far, have been due to poor tuning or ignoring your gauges. Has anyone (heaven forbid) had to tear a motor down and see what caused the failure? Bad piston? Rings?

My impression of Meth (I may be misguided here) is that if you run Meth that you need to tune for it, otherwise you lose some performance. If you tune for Meth, than you MUST ensure you never run out under boost. I've chosen not to run Meth injection at this point relying soley on water temperature and oil temperature to keep me safe. I know this doesn't address knock, but my tune is ultra-conservative (famous last words) and my knock sensors have not been turned off or "desensitised".

I've gotta believe if you guys can run 12psi, keep the a/f ratios right, don't tamper with the knock sensors and watch your temp gauges you should be fine. Am I missing something else?

CVP33
07-29-09, 05:19 PM
your foot.

Hilarious. And true. :sneaky:

Gary Wells
07-29-09, 07:22 PM
Hilarious. And true. :sneaky:
I meant no disrespect, couldn't resist the temptation. I was going to go "Yur fut" but I figured that I would banned for possible ethnic jokes.

CVP33
07-29-09, 07:54 PM
I meant no disrespect, couldn't resist the temptation. I was going to go "Yur fut" but I figured that I would banned for possible ethnic jokes.

I love ethnic jokes. You almost have to when you're 1/4 polish. This indignity of it all. :nono:

Gary Wells
07-29-09, 09:36 PM
From my experience running 100 octane unleaded in a 12.7 sec (not very fast) '87 turbo Buick and from running methanol injection in the same car is that:
If you run methanol and don't tune for it, you're definitely losing some performance.
If you're running methanol and you run out of meth under boost, your motor and / or head gaskets might be toast, depending upon how much boost you were running.
The difference between running 100 octane in a turbo brick tuned and chipped for it and running methanol and a meth chip in a turbo brick tuned for it is probably about 2 lbs of boost. The general consensus amongst turbo brick owners is that with meth you will make about the same RWHP & RQWTQ with about 2 lbs of boost less, or you can run about 2 lbs more boost with methanol than with 100 octane unleaded. That's what they figure the benefit of the cooling effect with meth over the equivalent octane rated fuel. Of course, this is all speculative at best. I run about 20 lbs of boost on the street with no detonation and / or spark retard showing on the scanmaster with meth and a TurboTweak meth chip. I don't know how that would compare / compute with meth set up for a CTS-V. HTH

PSRmark
07-29-09, 09:57 PM
From my experience running 100 octane unleaded in a 12.7 sec (not very fast) '87 turbo Buick and from running methanol injection in the same car is that:
If you run methanol and don't tune for it, you're definitely losing some performance.
If you're running methanol and you run out of meth under boost, your motor and / or head gaskets might be toast, depending upon how much boost you were running.
The difference between running 100 octane in a turbo brick tuned and chipped for it and running methanol and a meth chip in a turbo brick tuned for it is probably about 2 lbs of boost. The general consensus amongst turbo brick owners is that with meth you will make about the same RWHP & RQWTQ with about 2 lbs of boost less, or you can run about 2 lbs more boost with methanol than with 100 octane unleaded. That's what they figure the benefit of the cooling effect with meth over the equivalent octane rated fuel. Of course, this is all speculative at best. I run about 20 lbs of boost on the street with no detonation and / or spark retard showing on the scanmaster with meth and a TurboTweak meth chip. I don't know how that would compare / compute with meth set up for a CTS-V. HTH

We've had pretty good luck with Meth on the Xlr-V's and STS-V's, I should be starting the testing on it next week to see if it helps the AIT 2's.

Gary Wells
07-29-09, 10:05 PM
We've had pretty good luck with Meth on the Xlr-V's and STS-V's, I should be starting the testing on it next week to see if it helps the AIT 2's.
Mark:
Can I come visit? Seriously?
I'm basically right around the corner from you if you're there at D3 in Signal Hill. I'm about 5 miles from you guys and I would like to see what you guys can do for me in the way of a tune anyway.

radix
07-29-09, 10:15 PM
At the Eaton website there is a simulator that can be used to see the effects of various superchargers and pulley ratios if anyone is interested to play - http://www.eaton.com/EatonCom/ProductsServices/PerformanceProducts/Products/Superchargers/index.htm


I gotta say with some of the extreme pulley ratios around here, I would think the blower might be getting to be the weak link. Typically the designs spec out max speeds around 12,000 rpm and keeping below 14,000 rpm. With the swap to a 2.55 upper pulley you will be seeing blower speeds well over 20,000 rpm and the efficiency will be way down (if the the thing doesn't grenade)

here is blower performance map, notice 17,500 rpm is the edge of the graph...

CTSV_510
07-29-09, 10:36 PM
From a vendor's view they have nothing to lose. They get paid regardless of any poor outcome.


I really have to disagree with this.

Poor outcomes are very bad for business, especially in a business like automotive performance that is so reliant on forums like this.

So yes, the vendor gets paid for the overdrive pulley that over-boosted someone's motor even if the motor blows up, or for the tune that was deceivingly marketed as a "stealth tune" but ruined a customer's warranty, but then they have a large amount of potential customers that heard about it.

News travels FAST around here, good AND bad.

PSRmark
07-30-09, 01:24 AM
Mark:
Can I come visit? Seriously?
I'm basically right around the corner from you if you're there at D3 in Signal Hill. I'm about 5 miles from you guys and I would like to see what you guys can do for me in the way of a tune anyway.


I dont see why not...

i'll give you a heads up of when I plan on throwing this Meth car on the dyno, provided its ok with management...a.k.a. James :)

CVP33
07-30-09, 07:34 PM
Now there's an angle I didn't think of. At what point is the supercharger losing it's efficiency. Nice addition to the thread and definitely food for thought for you guys pushing the limits.



At the Eaton website there is a simulator that can be used to see the effects of various superchargers and pulley ratios if anyone is interested to play - http://www.eaton.com/EatonCom/ProductsServices/PerformanceProducts/Products/Superchargers/index.htm


I gotta say with some of the extreme pulley ratios around here, I would think the blower might be getting to be the weak link. Typically the designs spec out max speeds around 12,000 rpm and keeping below 14,000 rpm. With the swap to a 2.55 upper pulley you will be seeing blower speeds well over 20,000 rpm and the efficiency will be way down (if the the thing doesn't grenade)

here is blower performance map, notice 17,500 rpm is the edge of the graph...

wait4me
08-01-09, 10:22 AM
As far as making changes to the LSA, here is the bottom line on what was needed in order to
maintain reliability to go from 556hp/551tq to 638hp/604tq:

LSA vs. LS9

LSA has hypereutectic pistons 9.09:1 compression ratio.
LS9 has forged 9.15:1 compression ratio.

LSA has Eaton TVS 1900 supercharger.
LS9 has Eaton TVS 2300 supercharger.
LS9 has 1mm larger diameter head bolts for increased clamp load

LSA has powder metal connecting rods.
LS9 has forged titanium connecting rods.

LSA has 8-bolt flywheel crank.
LS9 has 9-bolt flywheel crank. Both are forged.

LSA has solid valves.
LS9 has titanium intake and sodium filled exhaust valves.

LSA rev limit is 6200rpm.
LS9 rev limit is 6600rpm.
Cam specs are different between LSA and LS9.

Intercoolers are different (1 brick on LSA vs. 2 bricks on LS9), but that was done more for packaging.
Accessory drives are different, but again for packaging. [/B]






Mike



Mike, im failing to see where/why you are posting this.

Just because the pistons are quoted as 2618 hypereutectic dont mean they wheren't a forged alloy process also.. hypereutectic pistons are used in most ALL diesel vehicles. Dont those handle 1000ft of torque and EXTREME temperatures well over what a supercharged gas engine produces? As in all the duramax, cummins, and powerstrokes..

So im failing to see them as a weak point. Also, They may be forged from the factory as part of the hypereutectic process.


On to the supercharger.

This does nothing on strength.

It does, however allow you to make more power with less intake charge temperature, BUT DOES NOT INCREASE STRENGTH of the engine or its reliability. Actually, from a weight standpoint and more rotation mass, it takes more power to run..


On to the Head bolts.

Again, nothing on Physical strength of the motor.
It just allows for more clamping force to hold the head gasket tighter to the block without stretching as much. One millimeter isnt that much extra clamping load. I have yet to see a problem with bad head gasket leaks from too much boost. Cars for YEARS have not had an issue with it if you use good bolts in the stock size.

On to the Rods,

Ok this would be a valid strength difference, however, the main change for this was for Higher REV capacity, not for strength. They wanted a higher reving motor, so they removed rotating mass for more HIGH RPM STABILITY.

At the horse power levels we are running, the Rods arent that much of an issue as long as we dont rev them to 6500+ rpms as the Zr1 was meant to be run.



Now the crank difference.

Cranks i see 0 difference in strength, so they are not worth bringing up except for the fact of them needing the extra bolt for the packaging difference on the 2 cars. The CTSV has ALOT more room and is fitted to the tranmission where as the Zr1 is remote location.



Now Valves.

Again, these changes where to help with HIGH RPM usage. Not a needed strength upgrade...

Titanium is lighter and helps take the load off of the camshaft lift / spring deflection and is easier on the drivetrain at higher rpms..

Sodium filled valves help cool the valve by dissapating the heat better thru the valve guide. Also lighter weight for HIGHER RPM stability..

We arent reving ours to those rpms, so again, not really a needed thing.



Now Cam specs..

How is this a strength difference????

If anything, the SMALLER cam size of the caddy is safer than the zr1 as it has alot less left.

So that isnt a valid weak point.




And lastely intercoolers...

The V intercoolers are better as they had more room for the packaging. The temps before and after the V are better than the drops in temperature on the dual cores in the zr1 package.

Even if the Zr1 was better, which it isnt, how would that increase strength of the motor......

CIWS
08-01-09, 11:03 AM
Mike, im failing to see where/why you are posting this. snip . .



So in your estimation you feel the LSA is capable of handling power levels up to 600 rwhp without any long term issues ? Long term as defined by the life of the standard warranty ?

Luna.
08-01-09, 11:05 AM
Interesting thoughts Jesse and I hope you are right.

The potential piston issue is seriously keeping me up at night

wait4me
08-01-09, 11:14 AM
Found a good read that even helps back me up.

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

Read the very bottom sentence: "pistons made from the most common 4032 and 2618 alloys are typically forged."

wait4me
08-01-09, 11:28 AM
STOCK PULLEY UPPER SIZE IS 2 7/8. Stock lower is 8 inch.

Ratios are simple to see differences of. You just take the lower pully and divide it by the upper.

So the stock with 2.87 upper pulley makes a ratio of 2.79.
With a 2.55 upper the ratio only changes it to 3.13.


A upper 2.55 pulley and 8.5 lower makes a ratio of 3.33 You get better grip with less belt slip in this configuration and less parasitic loss.. Also sets you up for future boost as parts become available to adjust boost levels.
A 9.5 LOWER and STOCK upper makes a ratio of 3.3 Works well, Almost as much horsepower as just a 2.55 upper pulley.
A 10 lower and stock upper makes a ratio of 3.48 Slips the belt when cold, Working on a fix for more spring tension and better idler placement now...

CIWS
08-01-09, 12:16 PM
Found a good read that even helps back me up.

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

Read the very bottom sentence: "pistons made from the most common 4032 and 2618 alloys are typically forged."


While out there looking around I found this about the LS family of engines. This is of course one of many opinions on the subject.

"Pistons
The LS9 is the only production LS engine with forged aluminum pistons; all the other use hypereutectic (cast) aluminum alloy pistons - varied mostly by diameter to accommodate various bore sizes. LS cast pistons shouldn't be used on applications greater than approximately 550 horsepower. Also, the LS7 piston's inner bracing requires the use of the matching LS7 connecting rod."


http://gmhightechperformance.automotive.com/94564/0901gmhtp-ls1-ls6-ls2-ls3-l99-ls4-ls7-ls9-lsa-engine-history/l92-cylinder-heads-forged-aluminum-pistons.html



So that might explain why the LS9 has the forged pistons.

CVP33
08-01-09, 05:54 PM
pwnd

:worship:

Short-Throw
08-02-09, 12:03 AM
Mike, im failing to see where/why you are posting this.

Even if the Zr1 was better, which it isnt, how would that increase strength of the motor......

Jesse,

I'm not sure what you're failing to see, the differences I posted show the changes it takes to maintain reliability. This has been proven with millions of dollars on testing, not just a hunch on what one thinks a supposed higher threshold might be.....and keep a 100K warranty.

I appreciate your vigor and am not trying to discourage anyone from modding their car, far from it, just want them to be informed of cause and effect, and to do it on their dime. Heck, if these cars weren't so luxurious, I probably would have gutted mine by now.

Again, let me repeat myself. I'm all for gaining more performance whether it's chassis or HP, but to proclaim that such changes will have no effect on longevity is simply malarkey.

Have you personally calculated the cylinder pressure and clamp load of a cylinder head?


STOCK PULLEY UPPER SIZE IS 2 7/8. Stock lower is 8 inch.

Ratios are simple to see differences of. You just take the lower pully and divide it by the upper.

So the stock with 2.87 upper pulley makes a ratio of 2.79.
With a 2.55 upper the ratio only changes it to 3.13.


How are you taking these measurements? I believe they are incorrect.

The stock crank is 200.92mm or 7.91inches and the SC pulley is 78.48mm or 3.09inches resulting in a SC ratio of 2.56:1.

Anybody want to guess what the LS9 ratio is?

Furthermore, Eaton suggests a max rpm of 18000 for either the 1900 or 2300 SC. To get to the higher boost levels of the LS9, the 2300 was required to keep rpm within the 18000rpm with the higher engine rpm limit.

Do you honestly believe that has nothing to do with strength or durability?


So in your estimation you feel the LSA is capable of handling power levels up to 600 rwhp without any long term issues ? Long term as defined by the life of the standard warranty ?

?????????????




OFF TOPIC: I still want to set up a day at Autobahn for a stock vs tuned V's day. No agenda, just some real world fun! It was a blast seeing the Grand Prix there last weekend!


Mike

Gary Wells
08-02-09, 12:13 AM
Short-Throw:
Very informative post, Mike, thanks for the info.

CIWS
08-02-09, 08:42 AM
?????????????

Mike


Well he seemed silent on an answer so I took that for what it was worth. Silence can speak volumes.
As already expressed in various posts in this thread I have a hard time believing GM would have built up the LS9 if the LSA's design was capable of handling it's stock power rating and not have any longevity issues to deal with. However truly time will tell and we should know something within a couple of years if folks keeps their cars modded to those levels.

Now if someone would just come up with a way to disable the adaptive headlights and keep them just pointing forward. :)

OldRoadDawg
08-02-09, 09:18 AM
Now if someone would just come up with a way to disable the adaptive headlights and keep them just pointing forward. :)
Pg 3-19 of the owners manual: Adaptive Forward Lighting System
"Moving the switch (re: exterior lamp switch) out of the AUTO position will deactivate the system."

CIWS
08-02-09, 09:23 AM
Pg 3-19 of the owners manual: Adaptive Forward Lighting System
"Moving the switch (re: exterior lamp switch) out of the AUTO position will deactivate the system."

:D This is good news. Should I be surprised my salesman didn't know ? (I've got my eye on the coupe, but this was keeping me from considering)

marktanner
08-02-09, 11:35 AM
Not that this thread has anything to do with headlights, but to be accurate, moving the switch toward you (one click down) turns off the system, including the DRLs. Turning the switch all the way to ON, not auto, turns the lights on without the swivel. Valets sometimes do this inadvertently. I happen to love the swivel, but to each his own.

As far as the pistons go, has anyone considered that GM might put in a safety margin for people who mod? While officially discouraged, people have been modding for decades, and it wouldn't look good if the engine grenaded with slight mods, especially if the competition's engines can take it. Now, making a ZR1 out of an LSA is another matter. It would probably do okay if left stock, but I doubt there's much margin left for any mods at all. Plus, the ZR1 is more likely to see track duty more frequently than the V; it's just that kind of car. The ZR1 would then likely see more full throttle and red line activity than the V. The ZR1 really looks pretty track ready for a road car, except for the seats (they should really offer the Recaros or something similar). That's why it has forged pistons, titanium con-rods, ceramic brakes, giant tires, carbon fiber, and a $105K price tag.

As it stands, rebuilding or replacing an LSA will be a lot cheaper than an LS9. We really have a lot of car for the money. I'm just not sure it's reasonable to expect bomb proof reliability from extreme mods from a luxury car in this price range. Just remember, this is a supercharged base Corvette motor, not a detuned ZR1, apply some reason, and we should be okay.

chris1268
08-02-09, 07:38 PM
Jesse,





OFF TOPIC: I still want to set up a day at Autobahn for a stock vs tuned V's day. No agenda, just some real world fun! It was a blast seeing the Grand Prix there last weekend!


Mike

Hey Mike....as always thanks for the info.

On a side note I can bring mine out to run with you to see what kind of differences there are stock vs. tuned. Just give me a call if you want to play :thumbsup:

Short-Throw
08-04-09, 11:49 AM
Short-Throw:
Very informative post, Mike, thanks for the info.

:thumbsup:


Hey Mike....as always thanks for the info.

On a side note I can bring mine out to run with you to see what kind of differences there are stock vs. tuned. Just give me a call if you want to play :thumbsup:


Chris,

My schedule lightens up in a few weeks, let's try to get a date. I'm happy having anyone out that wants to drive their V on track. All they have to do is cover the guest fee.


Mike

Short-Throw
08-06-09, 05:55 PM
We really have a lot of car for the money. I'm just not sure it's reasonable to expect bomb proof reliability from extreme mods from a luxury car in this price range.


Exactly. Think of a rubber band. You can keep stretching it until one day.......SNAP! The heck with restoring factory like settings after you mess up, that's simply fraud. If you're going to mod it, take out a blank check and do it right. Then get out there and represent this great car!


Mike