MaxPF
AGNTSA
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Has anyone actually done it...?
I've done it plenty of times on V8s. You just go into the ECM and shut off the post-cat O2 sensors.
Has anyone actually done it...?
remove the mufflers and run a straight pipe from the cat to the tailgate.... trust me, the mufflers add the equivalent of at least 20' of pipe worth of back pressure.
Thanks.. thought about canceling the muffler on the borla, but I'd probably get an electric cutout instead, its illegal to run a straight pipe here.
Depends on the muffler. You can see straight through the Magnaflow I have on my truck. It has no protrusions of any kind into the exhaust stream.
Thanks.. thought about canceling the muffler on the borla, but I'd probably get an electric cutout instead, its illegal to run a straight pipe here.
were it me, if I got stopped, I'd argue that the cat is a muffler (and I've had this argument before - and won)...
you can see through it, but it has perforations that open into a batting - that actually kills flow because it's dropping the air pressure in the muffler and creating collisions with the air. Most of the turbo style have louvers that are cut to pull flow and create immense back-pressure - but it looks like it flows because you can see through it. The best, for flow, is the flowmaster design which uses waves to cancel out sound, but actually helps flow and decrease backpressure
Dyno tests disagree with your assertions.
You can't race a dyno - here's a good example of that. I have a good friend with a 598 ci BBC (Dart block) in his 68 Corvette, I had a 74 Corvette (I have a 75 now, I'm sick, I know it) with a 427 in it. Dyno hp - he had me by nearly 250 hp (750 to my 500). All except for the motor was exactly the same between the cars (okay mine was mostly white, his was mostly red to be absolutely accurate) - same suspension, same stripped back-breaking ride, no interior, etc.... I'd eat his lunch every time we raced at PIR. On paper, that 598 made a lot more hp, in the real world it simply meant his tires either went up in smoke in the corner or our drag races down the back-stretch would give him another long-distance view of my tail lights.
If that doesn't convince you
any "power increase" of less than 5% isn't repeatable - temps, moisture, altitude all make enough difference that even if the test was back to back - morning/afternoon, there's enough of a difference that it's not the same test. Now, I'm not saying that dyno results are optimized (a clever word for "cooked") but I am calling them liars....
If we are talking about dyno's, there is usually a 3% error between pulls, even back-to-back pulls before the car is taken off the dyno. How hard the vehicle is strapped onto the rollers and how much the engine has heat soaked are just a couple variables. Lets not even talk about calibration error between different dyno machines or manufacturers. The other stuff like temp, altitude, humidity (basically all the stuff that effects density altitude) are adjustable on the dyno. You could take a Yugo that just made 33hp on the rollers and adjust it to say it now makes 100hp by twiddling the dials. For the purposes of the H3, I WILL "race a dyno". We just are not putting down enough power that excessive HP is a problem and 30HP should be enough of a bump that it repeatably shows on the dyno and on the street.
You're a very persuasive guy then. I'd probably win a ticket to pick up my truck from the impound 30 days later.. With a bit of over-arguing, they might just park it in the sun, and roll down my windows.
After doing some more driving with the new tune, I definitely feel an improvement overall... Anyone wants to get rid of their old headers?
what you are looking for which as I understand it is more low end power correct?
Wat we really need are headers for the Alpha! Now that wld b great!
I put header(s) on my 2006 and it made a significant difference. However, I think it needs a PCM tune because it seems to be struggling to reach the right gear before it gets to 50 mph. I now have an Alpha. It's much better on the low end. I have not tried the zoomies or flying toilet yet, but it's on my list of future mods.
Whether it is worth it or not depends on your disposable income. Very subjective, but it does make a significant difference. My 2006 is for sale for a very reasonable price. I suggest you buy it and try out the headers and decide for yourself.
I meant low end rpm in 3rd gear (which was a mistake).
Ok humvee.... So I will chime in on this. Either to save you some money or make you spend more.
There is a lot of info here
An AR-5 would fix that. Shorter/lighter tires would also help.