Bad day for ZZP
12-05-2007, 07:43 PM
#26
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backpressure bad scavenging good. It has to do with the exhaust pulses. Using them to create some suck where they meet so the pull the exaust out of the other cylinders.
12-05-2007, 07:50 PM
#27
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wow they are doing a huge discount. i signed up but i dont think i want it anymore.. wow.. i have the 2.4 i wanna header and stuff but im not tryin to loose hp wtf..
12-05-2007, 08:02 PM
#29
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but you see. having it supercharged you would need more airflow down and out the exhuast so im sure its better but for the 2.4 na guys i dont think its such the greatest idea..
12-05-2007, 08:11 PM
#30
to lose 17 hp, there's something going on there. that's a very large loss, and there's something wrong. it's not the header, i can't see that unless it's not on right.
12-05-2007, 08:17 PM
#32
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your buddy must have messed up the tune or something..now that you are getting more exhaust to exit faster tell him to tune that and get that horsepower back up there!
im looking at the short header myself, cheaper and apperently better
im looking at the short header myself, cheaper and apperently better
12-05-2007, 09:04 PM
#33
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There's nothing wrong with the guy. He tunes LS1's and LS2's etc all day. He's got Camaros, GTOs, Corvettes, Trailblazers everywhere. Hell today he just tuned a Corvette for nitrous and that **** was pounding 1000hp to the ground on the street. He took it up and down the road and it was a monster.
12-05-2007, 09:16 PM
#35
There's nothing wrong with the guy. He tunes LS1's and LS2's etc all day. He's got Camaros, GTOs, Corvettes, Trailblazers everywhere. Hell today he just tuned a Corvette for nitrous and that **** was pounding 1000hp to the ground on the street. He took it up and down the road and it was a monster.
12-05-2007, 09:26 PM
#36
What kind of dyno is he using? I've heard that the DYNAPACK dyno meters are the most accurate, since the wheels hubs bolt on the machine. When you use the roller dynos, there are a variety of things which could affect your run. For example, tire air pressure, rims, the car was strapped tighter than last time etc.....
By the way, have you checked your plugs? When my brothers LS1 Z28 was getting dyno tuned, they changed the pulgs and got 5hp and 10TQ.
Good Luck!
By the way, have you checked your plugs? When my brothers LS1 Z28 was getting dyno tuned, they changed the pulgs and got 5hp and 10TQ.
Good Luck!
12-05-2007, 09:37 PM
#37
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What kind of dyno is he using? I've heard that the DYNAPACK dyno meters are the most accurate, since the wheels hubs bolt on the machine. When you use the roller dynos, there are a variety of things which could affect your run. For example, tire air pressure, rims, the car was strapped tighter than last time etc.....
By the way, have you checked your plugs? When my brothers LS1 Z28 was getting dyno tuned, they changed the pulgs and got 5hp and 10TQ.
Good Luck!
By the way, have you checked your plugs? When my brothers LS1 Z28 was getting dyno tuned, they changed the pulgs and got 5hp and 10TQ.
Good Luck!
12-05-2007, 09:52 PM
#39
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Thread Starter
Yeah do you think it could cause that much loss and change of horsepower and all that?
I was probably planning on getting the extrude honed manifold as a last resort.
I was probably planning on getting the extrude honed manifold as a last resort.
Last edited by BULLETSSMOKE; 12-05-2007 at 09:52 PM. Reason: Automerged Doublepost
12-05-2007, 10:29 PM
#41
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12-06-2007, 12:00 AM
#43
IBTL... seriously dude.. there's no way your car should be peaking at 3500 or whatever RPMS then immediately fall off.. something's wrong with your car big time because even if you sustained close to all the torque you had at peak you would've gained .. don't blame things on the company that does quality work when you're tuner has no idea what he's doing if you're reading more torque then HP on our cars you definately got something wrong going on there
12-06-2007, 12:04 AM
#44
no you don't. not directed at anyone, but some people need to read up a little about how engines work, and how cars work in general. less backpressure is better. there's no way around it. backpressure = restriction. they go hand in hand. the way to increase backpressure is to increase restrictions. if backpressure was good, there would be no such thing as mandrel bends, and high flowing cats, mufflers, and resonators.
between people thinking backpressure is a good thing, thinking you're supposed to double clutch a car with synchros, and rev-matching is bad on the car, i'm losing a lot of faith in the cobalt community.
between people thinking backpressure is a good thing, thinking you're supposed to double clutch a car with synchros, and rev-matching is bad on the car, i'm losing a lot of faith in the cobalt community.
12-06-2007, 12:13 AM
#45
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well i see some people saying negative things about the extrude honed manifold...but i can get a hell of a deal on the gm manifold, like as in $150.00 brand new. what do you guys think?? would it be much better then the stock one?? i know probably not as good as another after market, but for that price and comparing to stock, what do yall think??
12-06-2007, 12:18 AM
#46
and don't get me wrong, there's nothing wrong with being.... wrong 
i get things wrong sometimes, just like everyone else, and i certainly don't have a problem admitting that there's things that i don't know anything about. but what gets me is how adamantly people believe something is true, when it's not. when you try to explain the right way, they still don't believe you for whatever reason, to the point of starting fights or calling names. it's quite silly
i get things wrong sometimes, just like everyone else, and i certainly don't have a problem admitting that there's things that i don't know anything about. but what gets me is how adamantly people believe something is true, when it's not. when you try to explain the right way, they still don't believe you for whatever reason, to the point of starting fights or calling names. it's quite silly
12-06-2007, 12:20 AM
#47
Senior Member
well i see some people saying negative things about the extrude honed manifold...but i can get a hell of a deal on the gm manifold, like as in $150.00 brand new. what do you guys think?? would it be much better then the stock one?? i know probably not as good as another after market, but for that price and comparing to stock, what do yall think??
thats a great price.
12-06-2007, 12:43 AM
#50
On some cars back pressure can help with low end torque. It is never good for upper RPM HP. Since this build gained torque and lost HP, there is another issue at hand.
Selling to an inexperienced market can be tough. In the LS1 crowd you would never see a thread titled "these headers made me lose 10% of my HP" because they know better. In this market where somone obviously doesn't know much about performance we're actually having a debate about how much power the headers made you lose. It's frustrating.
In tuning we've done builds with strange results. Take a Grand Prix, put in a cam and not change plug gap. The car will misfire and you may lose 50 HP. Someone who doesn't know anything would declare "this cam sucks, it made me lose 50HP". To a good tuner, they know that increased airflow blows out spark and you have to tighten gap. Doing so might then yield 100 HP over the first numbers. What does this mean about the cam? Nothing.
Similarly we would need to hear the car run, have MAF readings, spark readings and wideband O2 readings to know why this build lost power with the headers. With that information I'm sure it would be easy to diagnose and fix the problem.
Selling to an inexperienced market can be tough. In the LS1 crowd you would never see a thread titled "these headers made me lose 10% of my HP" because they know better. In this market where somone obviously doesn't know much about performance we're actually having a debate about how much power the headers made you lose. It's frustrating.
In tuning we've done builds with strange results. Take a Grand Prix, put in a cam and not change plug gap. The car will misfire and you may lose 50 HP. Someone who doesn't know anything would declare "this cam sucks, it made me lose 50HP". To a good tuner, they know that increased airflow blows out spark and you have to tighten gap. Doing so might then yield 100 HP over the first numbers. What does this mean about the cam? Nothing.
Similarly we would need to hear the car run, have MAF readings, spark readings and wideband O2 readings to know why this build lost power with the headers. With that information I'm sure it would be easy to diagnose and fix the problem.