I see it all over.
Any ideas?

 

not enough cooling,fuel,bad tune,small ass pulleys..when u go with smaller pulley,u have to have a almost perfect tune to be on the safe side(2.7" or smaller pulley)or BOOM

 

All here in AZ have blown it on 2.6" pulley trying to attempt 160mph runs back to back (not kidding it was pure stupidity in all cases that I can think of)

MY guess is pointing MORE at the fuel pump than the injectors. I think that the pump cannot keep up with the demands for that long, combined from the heat created by the multiple runs with improper cooling time in between runs.

 

per bill hahn jr.....too much air to numba 4

 

Most don't understand the basics of modifying or even worse in the SS/SC, the basics of forced induction.

Some do understand and choose to ignore and "push the limit"

Depends on the situation

 

Yeah all blew #4.

If you look at it. Number 4 is the First to get air, and the last to get fuel. Bad combo!

 

Never thought of it that way lol

 

its all about tuning and knowing the limits. Push boost to far without supporting mods or great tuning and kapow.

Or a mix of the two. And I agree with NJHK

 

i wonder if there would be an actual way to install some sort of runners into the manifold to help distribute the air evenly. would probably take a lot of flow testing.

 

I also see that people don't realize that the biggest enemy is indeed creeping up on all of them...

Heat.

The efficiency of the roots supercharger normally is low from the beginning. Increasing air pressure isn't going to make things better. It ultimately becomes this big battle of cooling vs heat when if you had a efficient compressor, this wouldn't be the issue at all and you'd be making more power.

 

Ok, I just wanted to see if some people know whats up. Because there is alot of poor logic, and "info" I see posted around. That has little to no facts to support it. I know this market for these cars, makes them for alot of people as there 1st performance car. So there is a limit amount of places to gain performance knowledge on your cobalt.
But people have to thing for themselfs, and use REAL data, and REAL perforce gains. For refrance on what they want to do to there cobalt, to reach there goals.

NOT EVERYTHING YOU READ IS TRUE.

The best source of data outside of having your own dyno, and testing parts yourself. Is what regular NON sponcerd guys are doing. Track numbers, and dyno numbers. You will quickly see what IS real world performance and what is just false marketing hype.

 

From my experience, Program a 11.3 AFR under WOT, use no smaller than a 2.7", port your blower, avoid methanol only tunes, Keep timing under 18* on pump gas, and stay under 120mph and no extended runs over 4,500rpms for more than a few minutes.

You should be okay if you keep it sane.

 

Yup, good general blanket sentense.


---Smaller pulley DOSE NOT EQUAL MORE POWER
Small pulley has less area for belt grip
More power LOST the spin the blower faster (also not good for belt grip)
More blower outlet temps (KR)
It dose not make you cooler or more "bad ass"

42.5 DO NOT SUPPORT A 2.8 PULLEY!!!!!!!!!!!!!!!!


DON'T DO HI speed runs with a stock IC system. The dual pass mod dosen't add fuild capacity. You need more fuild. Like with a cobra HE, or even a larger IC res. The IC can only remove heat while the fuild is cooler. Heat soaked your basically dont have a working IC system. This happens with little to no cool down times after going WOT, even a few short WOT pulls. Can heat up the IC fuild to be little to non cooling the intake charge. The high cly presssued form boost, with hott intake temp. Will find the weak link and destroy it.

Mail order tunes are not good. Low performace, and a high engine falilure rate. Look around. If your going to mod your car. you CAN'T afford not to have good custom tune.

A good tune is a good tune.
You will blow up, just as fast with a bad tune on a 100% stock car. As you will with a high modded 300whp 2.6 with a bad tune. Mods dont blow up some cars and not others. Bad tunes do, fact.

I'm going to bed

 

**** happens when you mod....

 

where can you get a fuel pump

 

I don't think there is an aftermarket fuel pump for our cars yet.

Everyone seems to think it works just fine, but I have strong suspicions.

 

We have gone to 323 whp (SAE) with a 10.0:1+ AFR(off the scale) with 100% stock fuel pump, stock filter, pump wiring. With just flow match 60's.

refer to my post about listen to the proven data, and not internet false claims.

 

I was referring to my suspicions. I don't just sit and read things online and take them to heart. I have built a lot of cobalts, and seen where they go wrong.

We are running our ~430bhp "La Bannana" on a stock fuel pump as well, since we don't really have a choice for anything else. But since we keep it under 115mph, there is not too much time for the pump to be over stressed. Now, it's not the only factor, but it stands out in my mind.

 

The thing about forced induction is that you dont want to run a perfect air/fuel ratio. You want to richen it out like Studderin above showed. Obviously your going to get more performance out of an engine if your running a 13:1 a/f rather then 10:1. But with the 10:1, your engine will be running cooler which in result helps it stay more reliable. Studderin, I was wondering what do you think the best a/f ratio would be for this car around 11:1 or 11.5:1??? The problem with some people is that they tune these cars like its n/a. Forced induction engines need to run cooler because of the temps going into the engine from the supercharger or turbocharger.

 

biggy that no body looks at ... Compression is to damn high on these motors for the boost people are playing with

 

people are modding without the proper monitoring.

"i have an a/f gauge, what more do i need?!!"
whats the cylinder temps?
"i have no idea"

ah ha!
42.5's can support a 2.8 IF {notice the caps kids, pay attention} you take the proper steps to ensure that you are not going stupid with it. cooling mods, water injection, a GOOD tune on it. im sure i will get flamed for it, thats fine. i, like other people with hp tuners, have this great ability to drop boost off via bypass valve. which is what i will be doing. the added torque, but keeping the same boost levels as the stage 2 pulley.

pure and simple, people are not monitoring egt's. you may not get any knock, but you have no idea what the temps are inside of the cylinders. hence broken, or melted ringlands

 

Guys i got a few questions for you since we are allready on the same topic.

What is the stock compression ratio on these motors and what is a "safe" hp limit on these motors while they are stock.

Are the pistons forged?The Rods? Basically, what is a safe number with a good tune is what i am asking.

 

there have been people pushing over 300-400 to the tire on the stock motor.

either with the bottle and a blower, or turbo.
gm rates the bottom end to "300hp" toyota rated the 2jz-gte to 400 when it first came out, now look at it

 

Area47> You said it well. Temps are biggest key here. And people should not be trying to push so much boost. I think people get air volume confused with boost. True you want to flow as much air as possible, but you don't want that much pressure. Boost is a measure of pressure, not an engines efficiency to move air. 15psi is the optimal boost level in these engines IMO. Why has my motor not blown?, because I don't push 20psi. Is my 15psi as fast as the cars running 20psi, YES! If you take the time to properly port the blower and the motor, you will relieve some of the boost pressure and gain airflow.

Boost=Heat, Airflow=efficiency



To answer the other questions.... We do not have forged pistons stock, and they are rated at 300hp. You can go higher if you use cooler boost, but it can be hard enough for the average person to get that high. Stock compression is 9.5:1, don't go higher than that unless you have a surplus of race fuel, and you only need to go lower if you want to run 20+ psi safely. There are some of us who are crazier than others, and who like being at the head of the pack. In our case it's like leading the race at the special olympics.