really? thats funny, cause in your 20 minute google search breaks to try and fruitlessly figure out the concepts I was explaining, you haven't got an answer for crank angle at TDC? Lets hear you're brilliant answer? All you did was post a stupid picture and go "HA HA, this is what the crank angle is". How about you demonstrate some knowledge and tell me crank angle is at TDC. And BDC while you're at it. and oh let's say
you tell me where the crank angle on cylinder 1 when cylinder 2 is at TDC? I'll stick with my answer, and you can go use your ounce of a brain and look up more nonsense on websites to prove nothing.

I have been trying to answer you're stupid questions you ******* retard. But no matter what concept, fact, or scientific law I bring up, you want a ******* website for it. Here's an idea, I know more than you, I have no reason to lie, shut the **** up and learn OK? How about you prove how smart you think you are and explain something, rather than POSTING A ******* WEBSITE. I could teach a chimp do list a URL and go "it's all in here" as an answer, but I prefer to demonstrate applied, not copied and unvalidated knowledge. You claim all this **** is credible, and how? Some buttplug posted it on a website? That makes it credible? Well I heard on a website that the Earth was flat, perhaps I should believe that. Gullible, uneducated fool.
I know plenty of books you ******* retard. they are called text books. There isn't any bullshit being spewed (cept from you). I'm trying to explain concepts to a yard ape who doesn't get them. It isn't BS saying that the first half a millisecond of combustion, pressures are incredibly high at 120000 psi. Don't believe me, go get a trash can, take about a pound of gunpowder, detonate it, and see if you can find pieces of the trash can. The explosion had a huge specific impulse created by the rapid evolution of gas (CO2 and water vapor, and possibly oxides of nitrogen depending on the composition of the powder), obviously as the trash can exploded and the gas expanded, the pressure drops (SIMPLE GAS LAW). Go look up "explosion reactions" in your chemistry text book you claim to have since you obviously don't get it. Think igniting gunpowder is different from ignition a fuel air mixture, think again. Specific impulse of ignition is what stops the piston from going up and sends it flying back down the cylinder. You think that if nitrous pressures were only 1200-1500 psi max it could crack a block in half? Don't be ******* ridiculous, the pressures inside the bottle in which nitrous is being held is between 1200-1500 psi when full and those bottles are in no way stressed whatsoever. A block will crack the same reason an overloaded cartridge casing splits; too much specific impulse, from pressures way beyond the tensile strength of the materials trying to contain them.

Even the concept of TOP DEAD CENTER, is beyond you. Top meaning piston at it's highest point, DEAD CENTER meaning the rod dead center in the cylinder straight up and down, and perpendiclar to the position of crank since it's a 90* engine. Maybe it's semantics, but inspite of all your pseudo knowledge and links posting, you haven't shown ******* ****, other than your ignorance and arrogance. Examples, similar instances, not good enough for you. Well you know what, if you need everything in a website, you can never be taught a ******* thing. If you want to see it yourself, go conduct experiments like the ones I've shown you. If you don't think that huge forces are being exerted from the explosion of fuel/air in an engine albeit for a very small period of time, then by all means reuse your cylinder head bolts every time, and don't bother replacing head gaskets. According to you (and the dumbed down website that didn't offer a single explanation for their numbers, which are more than likely an estimate or simply a typo), 1200 psi is all that is exerted by combustion, then that is hardly enough to fatigue a single bolt anywhere in the engine. btw, my "little" mind is far sharper, and more capable than your empty, closed, and diminutive mind ever would, could, or will be.
Anyways, time for , some of us have a future to work hard for (me), the hopeless failures like yourself can stay up all night copying and pasting website links. I suppose you tried this at school (since you claimed to go) and failed out. See most reasoning people like rationalized explanations, not links to bullshit pages. You haven't proven anyone that you know anything other than how to use Ctrl C and Ctrl V on the keyboard kiddo. Have fun failing at life, and don't ever talk to me again.

 

instead of quoting all of that i'll just say that u don't know ****. i read ur posts.... u didn't answer anything. your concept of the theories and laws u meantioned are a freakin joke. i'm actually amazed that you can fully type out a coherant paragraph.

it's cool if u have a fast car, and who cares if u dont' know about it, but trying to fake it is just . all you did was take your inability to understand anything and turn it into a bashing.

i'm not saying that there has been tons of proof laid out by adrenaline that everyone could understand, but anyone who can grasp the basic concepts of engine function should be able to see it. but i guess i just need to understand how things work instead of taking joe blow's word for it like everybody else is doing. "oh, his car is tyte fast yo, that boy knows mad **** bout da LS1s." i guess that because he's not an LS1 owner that he doesn't know anything .

 

I actually signed up just because of the sheer idiocy of the posts you're making 5-7.

I'd like you to explain to me, if the piston and rods are at a right angle to each other at TDC (so the crank throw is basically at 90*, pointing at the side of the oil pan), if you were to rotate the crank back 90*, where would the piston be? Wouldnt it go up? But how would that happen, its at TDC already?

Maybe you should check out:
http://auto.howstuffworks.com/engine3.htm

 

you guys lost me a long time ago I'm gonna go to bed and read up later.

 

I'm just gonna say this... this was the original post... I admit there was a misunderstanding between me and adrenaline but tim99 was asking about N/A motors and what was the highest CR for 93 oct. so yes he can run 12:1 and be fine with a decent tune... but many guys stick to 11.5 or 11 CR of course this depends on the lift of that cam because you dont want to tag any pistons.

 

With his cam at 11.5 SCR he'll see 9.2 DCR. This is with stock stroke, .033 squish, etc.. I think this is a little high...

It looks like we're running a different cam now anyway, the other one was too big. What's a good SCR to shoot for on the street? Assume ~.035 quench

 

You know what 5-7,

YOu are too basic to even understand the concept of advance timing.

You believe that engines make the most power with ignition timing at Zero
degrees

You expect anyone to believe a inch of what you type after posting that
crap? Ever hear of spark timing advance? You know 18 degrees, 25 degrees,
30 degrees BEFORE TOP DEAD CENTER.

Then I post diagrams from a BOOK
and you're still harping on the Internet link BS.

Finally there are some people starting to come around Ty_Ty, RoadRage,
70Firebird, Tim, CamTom and a few others from early on.

5-7 signs up and starts bashing me immediately with a bunch on nonsense
he can't even prove. I truly believe you're a friend of one of these long time
members and you're here just to start ****.

How dumb is this quote:



I have never seen such a bogus formula before. Did
you make that up with your alphabet soup last night?

The basic formula for combustion looks something like this:

"The chemical stoichiometric combustion of hydrocarbons with oxygen can be
written as:

CxHy + (x + (y/4))O2 -> xCO2 + (y/2)H2O

Often, for simplicity, the remainder of air is assumed to be nitrogen,
which can be added to the equation when exhaust compositions are required."

As for crank angle at TDC, think about it - it will be Zero degrees.
Crank angle is measured from the cylinder bore centerline, not opposing
cylinders.

Guess what 5-7, the crank angle is zero degrees at BDC as well!

Would you like me to draw that for you? Maybe I can show you the trig math
behind that?

5-7, you look more and more like a child with every post. I enjoy ripping you apart.

 

you guys are al worthless waste of reading time.

To answer original question, yes you can run 11 to 12:1 compression and spray the car. Big shot you may want to consider some good gas, in adition pull da timing out of it by lots.

We sprayed a few 11.5:1 motors no problems on pump gas 150-200 hits. An idiot can blow up a 10:1 race gas fed motor on the gas, or a smart guy can run 11.5:1 decent cammed motor that still runs off the jug, and runs just as good on it. You guys chose which one you would rather be and shut the hell up. Ask guys that actually spray these motor with what your talkign about doing, and ignore these other dumfuxs.

 

Adren, not trying to step on toes here, but all your posts and links and pics dont mean **** to us. you can prove as many points as you want, and paper trails are always good, but when building a motoor, i sure as **** would listen to someone like myself with a car running 9's with a small 347 and a shot of spray over a book that tells you ***** Squared times the root value of the flux capasitor plus the **** sling aproch angle should give your your disiered Compression!
I dont know al the technical words you know and im not sure on all the links, but my car runs, and runs fast so i must have done somthing right.
again, all the stuff you post seems to suport your statements, however what you sat isnt what works with these cars.
who knows with a Older small block all your statments may be 100% true, but this LSx stuff is so far advance with better this and better that, all the low CR **** may not apply anymore.
and for what its worth, i figured my CR with the guy that did my heads and block work and the guy that did my pistons. between us we figured the CR, so it wasnt with some desktop thing.
also I DO run race gas so i wouldnt recomend to the origalan poster to run much over 11-1 CR and thats that.
go easy on me im sensitive,

 

 

I think its pretty simple. The higher the compression motors can be run on pump gas with more valve overlap ie lower lsa. Lower compression motors tend to make more power with less overlap. I've seen 12.5:1 compression in an ls1 on pump gas and a daily driver. Now it loped like no tomorrow and had to idle closer to 950-1000.

Bottom line. If you want to safely run pump gas and 11.5 compression w/spray..i wouldn't run a cam with a 114 lsa. You really need to look at your cam specs and see what kind of valve overlap your looking at. Your cam cam make or break performance with high compression.

 

I will try to get time to look through this tread after while.
I have not read all this so I dont really know what all yall are arguing about.
However my fast answer to the poor guy that was just looking for a small simple answer is this.
These newer age fuel injection cars can handle higher compression applications with out running race gas.a 11.5 application would be just fine.The nitrous tune may change.Depending on the size nitrous shot the person is spraying. They may need to run a better fuel and ofcourse the tune will very as far as timming.

Boost and nitrous are to different things.Idea would be to run a lower compression motor on boost.On nitrous its ok to run a higher compression motor.However with a high compression motor the tune up is less forgiving.In another words the higher the compression the more critical the tune up is.

We have built several 12.1 LT1 cars that run on 93 octain.Of course this is border line and if they use nitrous I would suggest atleast 104 and timing pulled.



My LT1 was 12.5.1 compression.This car made 392/398 on motor through a nine inch and big converter.On a 200 hp shot it made 622/735.

I could run pump gas on the street if I had to but had to run race gas on the juice.

 

Cool, a response from a nitrous tuner.

That quote pretty much sums up this entire poor excuse for a thread.

All those people that slammed me for quoting info, links, books to state the
SAME DAMN THING Nitro Dave just posted, can suck me off.

 

sorry dude, but you have issues.

 

Umm most of us never argued with you we just argued what you could run... IM not an engineer all I can say and most of us can say is that we run high compression motors with a good amount of juice with timing pulled and have no adverse effects and make tons of power..Its just foir a while there you were trying to tell us its impossible and thats why everyone came in here..
IM running a
383 LT1 11:5:1 Comp
236/245 114lsa .569/.580
and Ill be spraying a 250 on it but not with 93 octane

 

No, I never said it was impossible, that's where everyone is mixing up my position.

I said IT's NOT THE BEST METHOD.

I also said, it can't be done effectively on pump gas.

Everyone that has 12:1 + compression and more than 100 shot is using higher
octane.

That's why I'm getting so frustrated with everyone that challenges me.

Now Nitrous Dave posts the same thing, and he's acknowledged.

 

Why, because your quest to prove that you know more about LSx motors came to the conclusion that your SBC theories do not really apply here?
Also because he reafirms that N2O doesn't act like boost and is not boost?

No one here questions your knowledge, but the way you put things across is pushy and rude.

You do not own an LSx, you've never worked on a LSx, you've never rebuilt or modded an LSx, yet you think that your theories (and that is all they are) are the gospel.

By now you should be convinced that LSx motors prefer higher CR (~11.2:1) on 93 Octane (Tune adjustments needed)

When you stated that a 9.0:1 motor with a bigger shot of nitrous is the way to go, let me tell you another angle where that theory is faulty from a user point of view > Bottle pressure.
A bottle will hold higher pressure through the run if a lesser amount is dispensed. Bottle pressure (~900 >1100psi) is rapidly lost under big shots and therefore less effective at the end of the quarter.

You seem to enjoy knowledge, so add LSx to your arsenal by absorbing facts in order to present valuable advices with on hand knowledge of the LSx motor.

I don't think that any of us "sucking you off" will improve that. Not to mention it is

 

I never said nitrous was boost. I said it was a charge volume adder which
increases cylinder pressure. Raising effective compression by any means results
in higher cylinder pressure.

As for SBC theories applied to the LSx, it's pretty much the same deal across
the board.

Sure the LSx series has superior design that allows more potential from nitrous,
or fuel in general, but the LSx motors have not re-written the laws of physics.

Yes, I've come across rude, but when 100 people are cutting up valid facts,
it makes you a little angry ... so I'm sorry for that.

If everyone can understand that pulling timing is detrimental, then we can
agree that higher compression and nitrous isn't the best method.

First asked yourself why timing is pulled (retarded) and what happens when
you ignite the mixture later in the cycle.

You have a certain amount of charge in the cylinder and it combusts fully in
a given amount of time.

If you start ignition at 30 degrees BTDC for instance, the charge begins to
exert pressure on the piston as it rounds TDC. As the charge expands during
combustion, force continues to be applied to the piston crown.

Using that same scenario, start ignition 6 degrees later (or 24 degrees BTDC).
Now the piston is rounding TDC and going downward as the charge begins to
expand.

So...the time that the crank angle transfers the most force to the crank has
a smaller window.

My angle is: Reduce compression. Add nitrous. Add timing for more continued
force on the piston during peak crank angle degrees.

 

but the nitrous-charged fuel burns faster (more available O2), so pulling the timing just adjusts the pressure-wave to where it would have been without the squeeze. Pulling timing during an N2O run makes more power. Now, when you stop the nitrous, you may make less power on an NA run with the timing pulled, but that's what makes it a nitrous tune, because it's tuned for the nitrous

 

What cars run 0 degrees advance from the factory? I've never heard of a gasoline engine producing fast enough combustion to do that. Granted in an ideal world we would run 0 degrees of timing, but in the real world the flame front doesn't advance that quickly.

Also one thing both you guys are forgetting is that quicker combustion not only allows you to run less timing, but also increases knock resistance. The less amount of time the end gases are exposed to heat/pressure, the less likely they are to spontaniously explode (knock). And yes, I've read this stuff in textbooks.

Also, the piston isn't producing any torque on the crankshaft at TDC. To calculate the leverage of the piston on the crank, you need to do something like this,
http://e30m3performance.com/tech_art...derivation.jpg
(yes cutting/pasting is easier than explaining...)