Why do I always hear about the forth piston blowing?

 

from what i understand its the furthest from our weak fuel delivery system and leans out b/c the car cand deliver enough fuel to it- of course i could be totaly wrong and get owned here in a min or two.... guess we will find out!

 

if your wrong atleast you sound smart

 

lol, it works if i do it in an area where no one else is around.... i dubt it works here..
i have to be good at it. im a car salesman. lol.

 

I think i read somewhere because it is the hardest working piston
although im not sure - thats just what i have heard

 

... ummm you could have atleast added something to suport your thery like i did,... lol

 

yea im looking dude lol

plus like i said its not my thery

its just something i read on this site

 

We have a returnless fuel system so #4 is the last in the line. Problem is that when people are running 60# injectors the fuel rail can't supply enough to the #4 injector since its last in line and BOOM

 

number fails because of heat. pure and simple. not detonation.
it is a widely known fact that the last injector on the fuel rail is 99% running a lot hotter, it gets less fuel then any other cylinder.

this applies to dsm's, honda's, ls1's whatever it may be.

one of two things are happening here. people running way to lean, not enough timing {low timing increases cylinder temps greatly} or just not paying attention to what the car is telling you.

if you're running anything under the 3.0 pulley, or have a crazy ass tune in the car. you NEED an egt. some might say. "well my a/f ratio was spot on, no KR. but it still blew up"

well, what were the cylinder temps????

ah ha, catch 22 kiddies.

there ya go in a nut shell

 

quick q: not to steal the thred but what the best way to cool cylinder temps? meth im guessing?

 

Meth will help as well as a second heat exchanger but the real problem with the SS/SC is that when running those super small pulleys (2.6, 2.5) is that the supercharger is spinning way past the point of peak efficiency meaning that it is making far more eat them it is worth for the amount of air it is moving. So the real solution to more power without burning up a cylinder is to swap the power adder out to a twin screw or turbo. Something that can move more air without creating as much heat.

 

^This is exactly the problem. I'm waiting for my new engine as we speak.

 

Would a return style fuel system help even things out?

 

yes! i am trying to peice together everything i need to do this right now.

 

Thats the theory along with adding another fuel pump to up the line pressure.

 

could, or a new style fuel rail, or a split rail. either one. could work better.

the blower is fine. what people are trying to do is band aid the power making process on these engines.

why is it, a k series rsx with the m62 can put down 280+ whp on 9 psi.
where as it takes us over 17 psi to do that. or nitrous.

same general design in the engine catagory.

heads? yep, ours flows like a napkin.
cams? power to be had, if done right.

water injection will help. i dropped 20 degrees in temps by dumping the coolant out of the h/e and putting in purifed/ bottles water.

 

i heard it was something to do with the cooling of cylinder 4 thats why it always goes

 

I completely disagree.

The LAWS of physics are on my side. Fluid dynamics demand that pressure in a closed liquid system is constant throughout the entire system. It means absolutely nothing that there are 4 injectors on the rail. If those 4 outlets cause so much flow that pressure actually does drop, then it drops evenly through the entire system, all the way back to the tank.

I actually have two alternate theories.

First, there are two ways for mixture to go lean. First is not enough gas. Second, and much more likely, is too much air. It is very possible the design of the blower outlet attached to the laminov tends to favor the #4 runner. And that is a gaseous system, so the air is most definitely compressable. I bet the inlet pressure at #4 is a bit higher then the rest.

Second, our engine cooling system favors the #1 side. Freshly cooled coolant enters the cylinder head right above the #1 cylinder, then flows across the block. By the time it gets to #4, it's as hot as its ever going to be before exiting the engine at the thermostat.

 

yeah i agree with the cooling as i mentioned before, i think Cameron(Blown-4-Banger) had mentioned that to me before, how can we like fix that?

 

this all leads back to excessive cylinder temps.

 

mmm.. good read. Thats y i picked up an autometer cobalt series EGT gauge and fuel pressure gauge. When I get a chance to pull of the manifold, we'll see whats really going on.

Anybody have an extra fuel rail for sale? Once i see if theres any fp drop, or not, i want to take the fp gauge out.


THanks,
Nate

 

You can not compare hp and PSI figures from two different engines even if they use the same blower because there are a lot of x factors.

The fact is that guys using the really small pulleys are causing the SC to make more heat then it's worth. With a 2.5 pulley you are using meth, a second HE, dual pass IC and the oversized injectors to cool the cylinders down because the heat is too much. Number 4 fails because of a variety of reason all related to the build up of heat. You can partly put the blame on the fuel system but it all boils down to heat. Running a more efficient compressor would go a long way to solve this problem.

 

1. K series engines rev much higher
2. They have higher flowing cylinder heads
3. Look at how much torque they produce
4. Look at where their max hp is at

You're basically comparing apples and oranges.

 

One thing people are leaving out of the equation is the location of the thermostat.

 

Don't K series also run at much higher stock compression? I think he was talking about a M62 on a stock K series?