Does anyone make any real parts for the LS??

[Barwick]

I tried the AEM bypass valve - and even worked with their tech support - in short - the V8 pulls too hard and actually causes the valve to open under high RPMs - so it cannot be used on the LS.

here is an old pic of my engine with it on:
http://www.llsoc.com/V2R1/registry/registry.svc.getobject.asp?id=1740

I'd tend to disagree on that. Vacuum is vacuum. A Honda at 8200 RPM (or 9000 RPM in the case of the S2000) is making a LOT of vacuum in the intake. A V8 should make about the same, more or less, regardless of displacement, I doubt the V8 makes that much more vacuum.

 

[Barwick]

Nope they sure dont. I wish they did. Low boost (6 lb) and conservative tune will probably have to do till we can get some pistons and connecting rods offered (probably never). It looks like someone will have to bite the bullet and call up oliver, with a stock rod and piston in hand, and pay the gobs of money to have billet ones modeled after the stockers. I already got a rough price quote. It was a few months ago, but I remember the word "insane" uttered out of my mouth.

It can be done, just requires the right tuning.

Within about 6 months of its release, Comptech came out with a supercharger kit for the Honda S2000 (11:1 compression ratio) that added 100 flywheel horsepower (took it up to 340).

 

[Quik LS]

I'd tend to disagree on that. Vacuum is vacuum. A Honda at 8200 RPM (or 9000 RPM in the case of the S2000) is making a LOT of vacuum in the intake. A V8 should make about the same, more or less, regardless of displacement, I doubt the V8 makes that much more vacuum.

Well - it was AEM tech support line that I worked with - confirming that the valve actually opened at WOT and they confirmed that I should remove it.

They had me perform a couple of tests, with it on, off and with plastic around it.

 

[rocket5979]

It can be done, just requires the right tuning.

Within about 6 months of its release, Comptech came out with a supercharger kit for the Honda S2000 (11:1 compression ratio) that added 100 flywheel horsepower (took it up to 340).

While tuning is allot when it comes to making power and doing it the right way, it is not everything. It cannot make up for purely overstressed parts that simply cannot take much more stress by the power they are making. Correct tuning can turn a nightmare project into a smooth one, but it cannot serve as a band-aid for everything. There will be a point, probably around 8-10 psi, where no matter how good the tune is things will break.

BTW that Comptech kit was probably a 6-7 psi kit from the numbers you just told me. These cars will be able to withstand 6 psi, but I wouldnt trust them for much more before I would feel like I was riding a fine line.

This car will be my daily driver so I will only be running 6 psi on my centrifugal blower until I got the money to buy billet internals for it, which will probably be never. I will be happy with the roughly 335 rwhp I should be making with that for a DD.

 

[Barwick]

While tuning is allot when it comes to making power and doing it the right way, it is not everything. It cannot make up for purely overstressed parts that simply cannot take much more stress by the power they are making. Correct tuning can turn a nightmare project into a smooth one, but it cannot serve as a band-aid for everything. There will be a point, probably around 8-10 psi, where no matter how good the tune is things will break.

BTW that Comptech kit was probably a 6-7 psi kit from the numbers you just told me. These cars will be able to withstand 6 psi, but I wouldnt trust them for much more before I would feel like I was riding a fine line.

This car will be my daily driver so I will only be running 6 psi on my centrifugal blower until I got the money to buy billet internals for it, which will probably be never. I will be happy with the roughly 335 rwhp I should be making with that for a DD.

Again, I'm new to this, but I think 6 psi on a 3.9L engine should be plenty. You're not going to set the world on fire with it, but with the right intake and exhaust setup (ported heads maybe? how restrictive are the stock heads?) you should be good for at least that 335 at the rear wheels you're talking about. I mean heck, I've seen people running 18 lbs on a 1.3L rotary putting down 550 rwhp. And I've seen people running 18 lbs on the same motor but with a different turbo put down only 350 rwhp. There's plenty of factors that go into it, and I'm sure one supercharger vs another will put out different numbers at the same intake pressure (and also different stresses on the motor).

You also have to remember, depending on how the engine is designed, each piston/rod *may* hit its max stress point at top dead center or bottom dead center, in the sudden shift from going up to down in an instant. The most stressful part of the engine cycle may not even be the combustion phase. And if that's the case, then it may have a lot more room to go as far as power.

 

[rocket5979]

You also have to remember, depending on how the engine is designed, each piston/rod *may* hit its max stress point at top dead center or bottom dead center, in the sudden shift from going up to down in an instant. The most stressful part of the engine cycle may not even be the combustion phase. And if that's the case, then it may have a lot more room to go as far as power.

The weakest link, connecting rods and pistons, will ALWAYS be stressed the most at the time of firing which is usually a few degrees before TDC. The rest of the time that particular piston that just fired is just coasting along for the other 3 strokes of the cycle while the other pistons fire.

What happens is when timing is advanced too far, or detonation occurs (possibly from too much boost on a high comp engine), you will totally overstress the connecting rods because they will still be on their upstroke when the plugs fire or the mixture spontaneously detonates. Think of it like hitting a baseball that is coming towards you really fast compared to hitting a baseball that is already going away from you. It takes allot more to catch up to the baseball traveling away from you, hence less stress.

There is a fine line in between those two extremes, which is why we advance timing only by a few degrees and not as much as detonation would cause. This kind of gives the compression cycle a little head start so that by the time the piston actually does reach TDC it will already have built up enough compression to make good power on the full length of the combustion stroke.

A good tune can take care of this up to a certain point. After that it comes to down to the quality of gas you get on a given day, and also the bigger factor being the total stress that the connecting rods can take. With the high compression and hypereutectic pistons that these cars have, they will not last long with boost much higher than 6-7 lbs. There will be exceptions and lucky guys who decide to run 9 lbs and make it for a while, but we are mostly talking about daily drivers that we don’t want to crap out on us on the way to work.

 

[Barwick]

The weakest link, connecting rods and pistons, will ALWAYS be stressed the most at the time of firing which is usually a few degrees before TDC. The rest of the time that particular piston that just fired is just coasting along for the other 3 strokes of the cycle while the other pistons fire.

What happens is when timing is advanced too far, or detonation occurs (possibly from too much boost on a high comp engine), you will totally overstress the connecting rods because they will still be on their upstroke when the plugs fire or the mixture spontaneously detonates. Think of it like hitting a baseball that is coming towards you really fast compared to hitting a baseball that is already going away from you. It takes allot more to catch up to the baseball traveling away from you, hence less stress.

There is a fine line in between those two extremes, which is why we advance timing only by a few degrees and not as much as detonation would cause. This kind of gives the compression cycle a little head start so that by the time the piston actually does reach TDC it will already have built up enough compression to make good power on the full length of the combustion stroke.

A good tune can take care of this up to a certain point. After that it comes to down to the quality of gas you get on a given day, and also the bigger factor being the total stress that the connecting rods can take. With the high compression and hypereutectic pistons that these cars have, they will not last long with boost much higher than 6-7 lbs. There will be exceptions and lucky guys who decide to run 9 lbs and make it for a while, but we are mostly talking about daily drivers that we don’t want to crap out on us on the way to work.

Regarding the first paragraph, I haven't seen the numbers on all the engines, but it is possible that at TDC and BDC the engine is actually most stressed. The engine is spinning at, say, 6000 RPM (or in the case of race motors or small 4 cylinders, 8000+ RPM, which makes the forces exponentially greater). We're talking on the scale of thousands of g's, but only for a split second, and probably much much less time than during the combustion stroke.

 

[rocket5979]

Regarding the first paragraph, I haven't seen the numbers on all the engines, but it is possible that at TDC and BDC the engine is actually most stressed. The engine is spinning at, say, 6000 RPM (or in the case of race motors or small 4 cylinders, 8000+ RPM, which makes the forces exponentially greater). We're talking on the scale of thousands of g's, but only for a split second, and probably much much less time than during the combustion stroke.

The pistons and connecting rods will ALWAYS be most stressed at the very start of the combustion stroke, right before the piston hits TDC. While there may be allot of stresses in the rest of the operation, that is where the most stress on the rotating assembly always will be. When the piston hits BDC it will experience some increased stress due to it rapidly changing directions, but nowhere near the stress that same piston will experience while not only rapidly changing direction, but also supporting the load of the combustion while firing. Trust me on this I know what I am talking about. I also think I know where your probably referencing your info from being that you made a rotary engine comment. That is a TOTALLY different engine design with its own set of problems. Being that the rotary engine doesnt have pistons, and also its rotors never change direction, the stress is more linear and smooth in a rotary versus a piston fired engine. The biggest problem your dealing with in a rotary engine is inherently low torque (comes with the engine design) and sealing problems with the rotor to the engine wall being that the temporary cupped combustion chamber is only formed for a little while and then rotor rotates and the new cup comes into places for another firing sequence. I could go on and on about rotary engines. The bottom line is with piston engines, the most stressed part of the whole cycle will be the start of the combustion process. Not meaning to seem like I am getting on your case, I am just aiming to clear things up.

 

[Barwick]

The pistons and connecting rods will ALWAYS be most stressed at the very start of the combustion stroke, right before the piston hits TDC. While there may be allot of stresses in the rest of the operation, that is where the most stress on the rotating assembly always will be. When the piston hits BDC it will experience some increased stress due to it rapidly changing directions, but nowhere near the stress that same piston will experience while not only rapidly changing direction, but also supporting the load of the combustion while firing. Trust me on this I know what I am talking about. I also think I know where your probably referencing your info from being that you made a rotary engine comment. That is a TOTALLY different engine design with its own set of problems. Being that the rotary engine doesnt have pistons, and also its rotors never change direction, the stress is more linear and smooth in a rotary versus a piston fired engine. The biggest problem your dealing with in a rotary engine is inherently low torque (comes with the engine design) and sealing problems with the rotor to the engine wall being that the temporary cupped combustion chamber is only formed for a little while and then rotor rotates and the new cup comes into places for another firing sequence. I could go on and on about rotary engines. The bottom line is with piston engines, the most stressed part of the whole cycle will be the start of the combustion process. Not meaning to seem like I am getting on your case, I am just aiming to clear things up.

Ok, if you add the forces together, it will make more force on the piston/connecting rod. BUT does that necessarily make for more stress on it? I don't know. The sudden change of direction might make a difference and put more actual stress on it. But yes, you're right that the total combined stress of the combustion plus changing direction would cause more force.

BUT now what if the engine is made to fire at 1 or more degrees after top dead center (I imagine turbo engines do this often when they retard timing one degree per pound of boost?)

 

[rocket5979]

Ok, if you add the forces together, it will make more force on the piston/connecting rod. BUT does that necessarily make for more stress on it? I don't know.

I do know. It DOES add more stress. Stress is force, force is stress. It is just an amount of energy applied against something to cause it to stop moving, start moving, or otherwise change direction.


The sudden change of direction might make a difference and put more actual stress on it. But yes, you're right that the total combined stress of the combustion plus changing direction would cause more force.

BUT now what if the engine is made to fire at 1 or more degrees after top dead center (I imagine turbo engines do this often when they retard timing one degree per pound of boost?)

Very rarely, IF EVER, will you encounter an engine that will not fire before TDC. When referring to retarding timing they are retarding it against the advanced timing they were already running. So if a car in stock form starts out as having 16 degree's of total advanced timing in it then you decide to add a shot of nitrous or forced induction and retard the timing 3 degree's then the total advanced timing would be 13 degree's advance. Also, timing advance and retardation don’t directly correlate to the size of the shot of nitrous, or lbs of boost your running. Say for instance your running a 75 shot of nitrous on a stock vehicle without higher-octane gas, and then you would probably want to retard timing by 1 degree or so. If you used race gas then you probably wont drop any timing, and if the octane were high enough and you were tuned for it, you might even advance it some. Turbo's will be the same in principal. Some things designed to let you run more boost while keeping timing is an intercooler and also race gas to name a few. The cooler the air charge going into the intake the more timing advance you can keep and the more power your going to make, because A. the air is more dense, and B. the timing is advanced further than it would be if you were running a non-intercooled setup. IF a person were to go by the rule of thumb you stated of one lb boost = 1 degree of retard then that would be one underpowered setup! That is a HUGE amount of timing retardation to boost ratio! Sorry but whomever told you that figure either didnt know their stuff at all, or had a VERY VERY VERY EXTREMELY inefficient setup and then wanted to be overly cautious on top of that! There is no set rule of thumb for this amount of boost = this amount of timing retard. It all comes down to what your setup is.

While I do frequent a luxury car site from what you see, I have a MUCH bigger background in racing and building cars for power. I know what I am talking about. I wouldn’t be saying these things unless I were 110% sure that it was that way. Once you’re on here longer and if you ever see me on any other boards you will understand that better. For now just take my word for it. Not meaning to come off as cocky but I know my stuff.

 

[Midas78]

While I do frequent a luxury car site from what you see, I have a MUCH bigger background in racing and building cars for power. I know what I am talking about. I wouldn’t be saying these things unless I were 110% sure that it was that way. Once you’re on here longer and if you ever see me on any other boards you will understand that better. For now just take my word for it. Not meaning to come off as cocky but I know my stuff.

Where did you get your education & auto background? You're not one to give a brief response straight to the point are you? Do you even have an LS? Please post pics of your luxury car, no not the one with the rag top and the missing hubcap with the purple window tint.

 

[rocket5979]

Where did you get your education & auto background? You're not one to give a brief response straight to the point are you? Do you even have an LS? Please post pics of your luxury car, no not the one with the rag top and the missing hubcap with the purple window tint.

Ok, I have dealt with you in two previous threads the last day and now I will deal with you in here. Like I said in my previous post in HERE it is a totally childish thing to follow my posts around and make it a point to criticize my previous posts. Only someone who knows they were totally owned would do such a thing. The WORST part about it was that I was still remaining civil in the exhaust thread and then you got to pull this crap by attempting to discredit me?!? Give it a rest. Not only did you come into this thread way too late, but you also didn’t get the meaning of it too. Barwick and I weren’t arguing at all! We were talking detailed tech. To my knowledge I don’t believe Barwick thought it was any sort of confrontation either. I got respect for people like Barwick that can sit here and have a good debate about tech talk and still remain reasonable. You, on the other hand, resorted to acting like a child. The worst thing was that in your attempts to discredit me and try to prove me as some sort of troublemaker, you have only proven that the troublemaker title fits you better. You my friend are a total hypocrite. Grow up.

 

[Midas78]

If anyone is curious as to what is going on, you can refer to the 149 mph thread and the LS Exhaust thread.

I know its ok for non-LS owners to visit the thread, but when being attacked b/c you want to put a custom exhaust on the LS car is a little ridiculous.

 

[Fla02LS]

If anyone is curious as to what is going on, you can refer to the 149 mph thread and the LS Exhaust thread.

I know its ok for non-LS owners to visit the thread, but when being attacked b/c you want to put a custom exhaust on the LS car is a little ridiculous.

Hmm...i noticed he didnt answer your performance education/background question or if he owned an LS. I dont know if anyone has seen the video of the mustang guy blowing his intake off with nitrous, but thats what these kind of posts and people remind me of, but i'm sure he'll say he worked with Carol Shelby or Mario Andretti. Something lacking in their personal life gets made up for with idiotic posts to a public forum. I love my LS and like reading about others experiences, but all the idoit postee's have made me visit here less and less.

 

[rocket5979]

If anyone is curious as to what is going on, you can refer to the 149 mph thread and the LS Exhaust thread.

I know its ok for non-LS owners to visit the thread, but when being attacked b/c you want to put a custom exhaust on the LS car is a little ridiculous.

....and the Scion thread(though you didnt seem to really be pulling much sh1t there).....Gosh that sure is alloot of threads I posted in that you just miraculously showed up in; especially being that some weren't even recently posted in.....

Attacked? Thats laughable. If you call someone voicing their opinion on something and then giving a few people a hard time when they get bent out of shape about it then I suppose it was an attack. ORRRR, you could call it an adult conversation. People are always going to disagree. I disagree with you just as much as you disagree with me and that is fine. What I did find to be a bitch move on your part is when you decided to look through my previous posts and try to start more crap from there.

The comment about the non-LS owners is weak too. The reason for this is that there is no better place to get a real and unbiased opinion than from an outside source. For the next 4 weeks until I make my purchase I will be technically an outsider, but that still doesnt mean that my opinion doesn't hold as much creedence as anyone else's here. Do we got to be Pro Baseball players to make such a comment as, "You suck! Go play for the Cubs!"??? NO, we don't.


Fla02 - If I recall correctly, you were the one that got into a debate with me about making the LS fast. You also were trying to refer to your car as an, "all out drag car" and then later tried to backpedal when I called you on it? This is the same Fla02, right? Hehehehe. Man I am not trying to start crap with you again either, but didnt you get schooled enough the first time we talked? Gosh I wish our convo hadn't been deleted by that loser hacker that messed with the site. Stop trying to jump on this little bandwagon merely because I hurt your little feelings before.

 

[dmgraz]

are you this guy?

http://explorerforum.com/forums/member.php?u=10040

because if you are, you've got my vote. I believe you know what you are talking about.