Flowmaster

[TheBrettster]

I'm trading my stock exhaust for a FlowMaster, is this a good thing to do and is flowmaster a good replacement.





2001 Chevrolet Blazer 4.3

[ZL1power69]

they sound good but don't flow very well.

[TheBrettster]

well is it better than my stock POS with dent in it?

[Eslhockey92g]

http://www.automotiveforums.com/vbul...d.php?t=571572

look at that, my 40 series flow master w/ side exit soudns awesome i think. If i find a ravin i may to the switch though

[98BlackTransAm]

Originally Posted by TheBrettster

well is it better than my stock POS with dent in it?

flowmaster's a noticeable sound/performance upgrade over stock (assuming cat-back) but there are better performance set ups out there.

[BlazerLT]

Go with a cherry Bomb Vortex.

They bought out Ravin's design and are practically the same thing.

Don't go with flowmaster, it won't do anything but drone.

[DetroitMuscle]

The only things that flowmasters actually live up to is their sound. Especially on f bodies, they flow less then stock.

[BlazerBoyLT98]

Originally Posted by BlazerLT

Go with a cherry Bomb Vortex.

They bought out Ravin's design and are practically the same thing.

Don't go with flowmaster, it won't do anything but drone.

But the Cherry bomb Vortex Classic. or V-Baffle???

[wolfox]

V baffle - the FloPro, Ravin and some Flowmasters use the semi-triangular velocity baffle inside the body tube of the muffler to make it's dstinctive tone.

[BlazerBoyLT98]

Nice. I need to do an exhaust soon.

[ZL1power69]

cherry bombs flow good but kill ur gas mileage

[98BlackTransAm]

Originally Posted by ZL1power69

cherry bombs flow good but kill ur gas mileage

how does a better flowing muffler hurt your mpg? doen't decrease in back pressure = increase in mpg?

[wolfox]

Decrease in backpressure too much on a 4.3 GM V-6 makes it operate a little wierd. It likes to have just the right amount still in order for proper EGR flow, O2 sensor feedback and allow the valve overlap from exhaust -> intake "stall" just a bit to help cool the exhaust valves from the natural scavenging that occurs with the draw created when the exhaust pulse streams down and through the collectors. Mess with this fine balance a little too much and the ECU doesn't know what to think on top of the *possibility* that you start damaging heads and exhaust valves with elevated temperatures. Further modification with headers/collectors usually means swapping all of that with new heads and valves that are hardened for the task. An ECM flash is also required to compensate for the new flow parameters and interpret fuel injection signals from MAP/MAF & O2 sensors. This is not to say it will not work, but I am one to err on the side of caution a little and upgrade *everything* in the path that is affected in this manner.

A FloPro is the most free flowing of them all, however, in our application the most I would venture to put on the truck would be a 750 with center inlet, offset outlet. (2.25" dimater tubes) This is bbout as close as you can get to the absolute edge without harming anything else; flow better than stock and save some dough while doing it. It maintains a token amount of backpressure so heads/valves stay cool, EGR does it's trick, O2 is metered properly and the ECU stays happy without tossing codes. And that's my . I got an immediate 11% gain in MPG with my muffler setup before I opened up and modded the intake to match it.

[98BlackTransAm]

Originally Posted by wolfox

Decrease in backpressure too much on a 4.3 GM V-6 makes it operate a little wierd. It likes to have just the right amount still in order for proper EGR flow, O2 sensor feedback and allow the valve overlap from exhaust -> intake "stall" just a bit to help cool the exhaust valves from the natural scavenging that occurs with the draw created when the exhaust pulse streams down and through the collectors. Mess with this fine balance a little too much and the ECU doesn't know what to think on top of the *possibility* that you start damaging heads and exhaust valves with elevated temperatures. Further modification with headers/collectors usually means swapping all of that with new heads and valves that are hardened for the task. An ECM flash is also required to compensate for the new flow parameters and interpret fuel injection signals from MAP/MAF & O2 sensors. This is not to say it will not work, but I am one to err on the side of caution a little and upgrade *everything* in the path that is affected in this manner.

A FloPro is the most free flowing of them all, however, in our application the most I would venture to put on the truck would be a 750 with center inlet, offset outlet. (2.25" dimater tubes) This is bbout as close as you can get to the absolute edge without harming anything else; flow better than stock and save some dough while doing it. It maintains a token amount of backpressure so heads/valves stay cool, EGR does it's trick, O2 is metered properly and the ECU stays happy without tossing codes. And that's my . I got an immediate 11% gain in MPG with my muffler setup before I opened up and modded the intake to match it.

ah gotcha,, yea I dont really kno much about the 4.3 v6's

[wolfox]

It's cool man, it's what we're all here for - to lean. It's all about exhaust velocities and the effect they have on head flow. If you let all of that energy pass without restriction, intake air/fuel mixture will not "dwell" or linger around and through the exhaust ports long enough for effective surface -> air heat transfer. That's the big killer. Everything else is curable with a proper ECM flash or Memcal update in the older rigs, like mine.

EDIT: Gotta remember, these left the factory as reliable, rock steady truck engines that run happily on regular pump gas. They generate great torque at sedate engine speeds, and though pressed, not really meant for continuous high speed operation. If you're going for a little more performance, the bolt on stuff works to a point. After you breech that point, time to think of complete engine mods, swapping stuff out of the bay or what some adventurous folks do - swap for the infamous small block V-8's and build them up to speed and power.

I turned a relatively tourqey, gas guzzling Ram 1500 into a decent street racer once, but it took all sorts of tricks in addition to just plain cat-back and intake mods to get it right. Dropped the dough to get matched flow injectors, beefier volume fuel pump, the performance DCM (and three different flashes until it ran right on pump premium fuel), cam, rear-end gearing, tranny toughening and enhanced cooling in to handle the increased engine output. Luckily, Dodge didn't make too much distinction between factory built engines and thier A-block crates making powerful, small block v-8 mods really easy. I was about to rebuild the entire bottom end of the crank and rods to really toughen things up some, but ended up selling off the truck for $7,500 more than I originally paid to cover a really rough spont in my life. I still miss that truck. *sniff* I'm content with my Blazer though, and try as I might - getting formidable power out of it is going to take considerable work and a few friend's favors that hve garages I can borow on weekends to get it all done right.