Hey guys im getting a SI-DO Flowmaster 40, what size what i get, im going to get 2.5" in but what size should i get out? I read 2" is fine to keep torque but what about 2.25"? What do you guys have/like?

 

Since you have a 3.0, I would say 2" duals for sure...lol.

 

2''? nah go with 2.25'' thats what a lot of people run here... when i had my ranger i had 2.25'' and it sounded good. no bigger than 2.5'' thats when you lose backpressure and power is decreased..

 

You will loose back pressure the larger you go....

The gibson exhaust kit for rangers is 2.5" in and dual 1.75" out. People who have it like it and notice a power and torque increase, so why is 2" duals too small?

 

i didn't say it was too small, i figure since the stock piping on rangers is 2'' INlet, you need to go a little bit bigger for the outlets. well at least on my old ranger the inlet pipe was 2 inch.

 

I'd say 2.5" in and 2.25" out duals just for the same reasons everyone else posted. -Mike-

 

I agree, are engines dont' really produce much low end power so if you go with 2.25" dual outs it will help the top end I'm guessing.

 

This is on the Gm trucks site I belong to, now look at the pipe sizes and the engine size, this is on a 350 Chevy. So for me it makes sense to use 2" duals since you only have a 3.0 V6 and not a 5.7 liter V8.



I'm not the exhaust expert by any means, but from my research I have found that those that use a single in/dual out muffler can usually maintain their low end if they use slightly smaller pipes running out the back. Then cap it off with a bigger echo chamber for the sound/look.

For instance, on my 5.7 I am using a Flow 40 series single 3" in and dual 2.25" out and it kept my low end in place while giving me the high end and mpg gains I desire. Another forum member, noted he used the same exhaust system and was able to maintain his low end as well while getting the duals out back and the sound he desired.

 

with my 5.2L i have 3'' inlet 2.5'' outlet and its perfect. how long it usually take for a flowmaster to break in fully? (on a v8)

 

Usually a few months on any motor. (I do believe)

 

alrighty then. i just got it put on maybe 2 weeks ago.

 

Dual 2.5"? in any event, on a V8 that may be ok. Remember, he is a 3.0. That isn't a very big motor....

 

oh yea 2.5'' is too big for the 3.0, maybe even the 4.0. 2.5'' outlet on a v8 isnt bad at all.

 

Ideally, if you go 2.5" in, to equal a 2.5" out (single), you would need dual 1.75" pipes, so 2" is plenty. If I read correctly, even D. has dual 2" out, and his motor is built.

 

I can't find any flowmasters that are 2.5" in 2" out. All the ones i see are 3"/2.5" or the rare 2.5"/2.25". Do they make 2.5"/2"?

 

Mines 3" in 2.5" out

 

a 2.5in and a 2.25 out will be fine. IMO even on a 3.0.

the flowmaster is restrictive enough that you can go a little bigger on the outlet pipes.

 

Yes they do, they have it on there web site. Hold on, I'll get the link....

Here ya go....

http://www.flowmastermufflers.com/pr...oducts_id=3399

 

D is running a free flow open muffler, like the borla or magnaflow design.

If you run the restrictive flowmaster with baffles and such then you can run a little bigger pipes.

 

Well if you do the formula, to keep the flow up on a 2.5" inlet pipe, the duals would need to be 1.75. So even if the flowmaster is more restrictive, 2" duals are big enough. IMO

 

2.25 is pushing it but it will work fine with not much loss in backpressure.

I know some people are running 2.5in and dual 2.5 out. that is big imo

but hey I am just running 2.25 SI and 2.25 SO. and loving it.

I have been down the road of dual exhausts. you dont get performance from duals.

Performance is the best and most efficient flow from your engine.

 

2.5" is too big I agree... 2.25 might be ok on a 4.0 but I still think that dual 2's is plenty on a 3.0. I am in the same boat as you, 2.25 all the way, but I have a 2.5 flowmaster coming (single in/out) so I will see if there is any loss or gain here soon....

 

On my 4.0 I have 2.5" Header back exhaust with a borla turbo muffler with straight through SI/SO..... I would have gone 2.25 had I gone dual. I think 2" would be better for a 3.0 personally. Well D has 2" and Nickster has 2.5" true dual. I eventually plan on doing 2.5" true dual when I go SC

 

I run a flowmaster 40 si do 2.5 all the way out infront of the right rear tire. I did notice a very small decrease in power, but the sound is pretty deep for a 3.0. The larger pipe woln't hurt my engine will it?

 

^^^^ No it wont hurt it, but like you said, you loose low end power, and to me, thats VERY important.