Borla 40664 & 40665 Mufflers

[Rusty Shackleford]

I've read through numerous "which muffler/exhaust" threads, and the Borla muffler seems to be a popular choice for what I'm looking for - not too loud, but a nice rumble when you hit the throttle. I don't want anything even mildly annoying.

If I understand correctly, both the 40664 & 40665 will fit my truck - the 40664 is 2.25" diameter and the 40665 is 2.5". Currently, the 40665 is $93.10 on Amazon with free shipping & the 40664 is $139.95 with free shipping. Obviously, I'm leaning towards the 40665 just based on the cost difference alone. Will there be any loss in performance by going to a muffler with a larger inlet/outlet size than the stock exhaust piping? I don't want to make this thing any slower or get less mpg's.

 

[lhsoulrebel]

I believe, and people can correct me if I'm off base, A free flow muffler has the potential to increase HP, sometimes at the expense of torque. MPGs should stay similar unless you stomp on the gas pedal.

 

[Rusty Shackleford]

I believe, and people can correct me if I'm off base, A free flow muffler has the potential to increase HP, sometimes at the expense of torque. MPGs should stay similar unless you stomp on the gas pedal.

That's understandable. I think I'm assuming that if I go with the 40664, which has the same inlet/outlet diameter as the stock exhaust piping, that I won't risk any loss in performance or mpg's. But if I go with the 40665, which has a larger inlet/outlet size, that I might see a drop in performance or mpg's. But there seems to be quite a few people on this forum that are running the 40665, and I don't recall reading anything negative regarding performance or mpg loss, so I might just be worrying about it without good reason.

 

[jgue467]

ebay is a hair cheaper: item# 161431332718 is the 40664 @ about $89w/shipping and item# 361049432413 is the 40665 @ about $90w/shipping.

Now the choice may be more difficult. I think unless the rest of the piping is increased I'm not sure you'd gain much benefit from the 2.5 over the 2.25. Others on here have repeatedly stated one of these borlas along with the deck plate mode has gained them 1-2 hwy mpgs. Let us know what you find! Luck.


Borla 40664 Borla Pro XS Muffler | eBay


Borla 40665 Borla Pro XS Muffler | eBay

 

[Rusty Shackleford]

ebay is a hair cheaper: item# 161431332718 is the 40664 @ about $89w/shipping and item# 361049432413 is the 40665 @ about $90w/shipping.

Now the choice may be more difficult. I think unless the rest of the piping is increased I'm not sure you'd gain much benefit from the 2.5 over the 2.25. Others on here have repeatedly stated one of these borlas along with the deck plate mode has gained them 1-2 hwy mpgs. Let us know what you find! Luck.


Borla 40664 Borla Pro XS Muffler | eBay


Borla 40665 Borla Pro XS Muffler | eBay

Thanks for the research! I'm such an Amazon junkie that I always forget to check ebay. I'll probably just go with the 40664 to keep everything the same size. I don't plan on doing the deckplate mod, at least for now. I do think I'll add the Airaid M.I.T. though to help the engine breathe a little easier.

 

[Rusty Shackleford]

Well, looks like I missed the boat on the $89 40664 on ebay. The seller was probably clearing out inventory and is sold out of it. The cheapest one on ebay is $150 and Amazon still has them for $140. So now I'm back to leaning towards the 40665.

So there really shouldn't be any issues with using a muffler that has a larger inlet/outlet size than stock?

 

[TheArkMaster]

You'll be fine. You're not going to dramatically reduce MPGs, plus you'll gain some high end HP. Thats where it counts most in my book. Post a video when you get it. I've always been interested in Borla.

 

[Nunyabiz]

It makes absolutely zero difference.
I went with the 40665 2.5".
When it is welded on they simply cut out the old stock muffler, slide the new OVER the existing pipe and weld it on, so technically all it does it make it slightly easier and probably a bit stronger weld, but since the old pipe goes right into the new short section on the muffler then the pipe stays exactly the same ID.
Other than the short little piece of pipe both IN and OUT the muffler is exactly the same.

While you may see a single HP gain or whatever it is negligible.
BUT you will see a boost in Throttle Response and you should see a boost in 'Highway" MPG by about 1-2mpg.
I cant say as that I have noticed much if any extra MPG in city.

Torque seems the same if it went down at all it would only be noticeable on a Dyno, not seat of the pants.
You can definitely feel that the engine breathes better though.

I think to get the best benefit you need to get rid of the silencer in the intake (Airaid is best option IMO) and do a deckplate mod that way you have better airflow going IN and OUT.

 

[Rusty Shackleford]

You'll be fine. You're not going to dramatically reduce MPGs, plus you'll gain some high end HP. Thats where it counts most in my book. Post a video when you get it. I've always been interested in Borla.

It makes absolutely zero difference.
I went with the 40665 2.5".
When it is welded on they simply cut out the old stock muffler, slide the new OVER the existing pipe and weld it on, so technically all it does it make it slightly easier and probably a bit stronger weld, but since the old pipe goes right into the new short section on the muffler then the pipe stays exactly the same ID.
Other than the short little piece of pipe both IN and OUT the muffler is exactly the same.

While you may see a single HP gain or whatever it is negligible.
BUT you will see a boost in Throttle Response and you should see a boost in 'Highway" MPG by about 1-2mpg.
I cant say as that I have noticed much if any extra MPG in city.

Torque seems the same if it went down at all it would only be noticeable on a Dyno, not seat of the pants.
You can definitely feel that the engine breathes better though.

I think to get the best benefit you need to get rid of the silencer in the intake (Airaid is best option IMO) and do a deckplate mod that way you have better airflow going IN and OUT.

Thanks for the quick responses. I'm going to go ahead and pull the trigger on the 40665 before anything happens to the prices. And I'll definitely try to get a video posted of what it sounds like after install.

 

[Nunyabiz]

Thanks for the quick responses. I'm going to go ahead and pull the trigger on the 40665 before anything happens to the prices. And I'll definitely try to get a video posted of what it sounds like after install.

here is what mine sounds like with both the Airaid intake and deckplate mod and Borla 40665.

https://www.youtube.com/watch?v=wmf0heg4-cU

 

[Rusty Shackleford]

here is what mine sounds like with both the Airaid intake and deckplate mod and Borla 40665.

https://www.youtube.com/watch?v=wmf0heg4-cU

That sounds a million times better than what mine sounds like right now. I love it. Hopefully I get similar results. Not sure if I'll do the deckplate mod or not.

 

[AZ4Running]

Is it just my speeakers or did that sound more tuner than beefy /truck? I want that deep rumble but do not want too loud and i was looking at the borla 40665.

 

[Rusty Shackleford]

Is it just my speeakers or did that sound more tuner than beefy /truck? I want that deep rumble but do not want too loud and i was looking at the borla 40665.

To me, it sounded real nice. Not sure if I'd go so far as to say it sounds like a tuner. Maybe somewhere between tuner and beefy/truck, to use your words. I'm not trying to make my 4R sound like something it's not. The 3.4 is not a big beefy powerful engine. It's a smooth running, well balanced engine designed for longevity, not pin-you-in-the-seat power.

Don't get me wrong, I love the sound of a good exhaust system on a V8 as much as the next guy. But it's kind of sad when people put these elaborate exhaust systems on a V6 and try to make it sound cool and powerful - people with V6 Mustangs seem to be the biggest culprits of this, at least in my neck of the woods.

Borla makes free flowing mufflers that help your engine breathe easier while adding a little bit of HP and accentuating the natural tone of the engine. If it sounds a little tuner-ish, that's just because the 3.4 is not a big displacement engine with a ton of power. I'll try to post a video or sound clip of mine after it's installed just to have another sample out there.

 

[Nunyabiz]

To me, it sounded real nice. Not sure if I'd go so far as to say it sounds like a tuner. Maybe somewhere between tuner and beefy/truck, to use your words. I'm not trying to make my 4R sound like something it's not. The 3.4 is not a big beefy powerful engine. It's a smooth running, well balanced engine designed for longevity, not pin-you-in-the-seat power.

Don't get me wrong, I love the sound of a good exhaust system on a V8 as much as the next guy. But it's kind of sad when people put these elaborate exhaust systems on a V6 and try to make it sound cool and powerful - people with V6 Mustangs seem to be the biggest culprits of this, at least in my neck of the woods.

Borla makes free flowing mufflers that help your engine breathe easier while adding a little bit of HP and accentuating the natural tone of the engine. If it sounds a little tuner-ish, that's just because the 3.4 is not a big displacement engine with a ton of power. I'll try to post a video or sound clip of mine after it's installed just to have another sample out there.

I was going to say exactly the same thing, a 3.4L with only 190HP is NEVER going to sound like a beefy truck unless you record a big beefy V8/V10 with 400+HP and then play the sound clip when you drive.

But having had both a Magnaflow and the Borla on my truck I have to say the Borla sounds about as throaty as you are probably going to get and remain pretty quiet at idle.
There is also no drone at 55-70.

 

[Rusty Shackleford]

I was going to say exactly the same thing, a 3.4L with only 190HP is NEVER going to sound like a beefy truck unless you record a big beefy V8/V10 with 400+HP and then play the sound clip when you drive.

But having had both a Magnaflow and the Borla on my truck I have to say the Borla sounds about as throaty as you are probably going to get and remain pretty quiet at idle.
There is also no drone at 55-70.

Yeah, there's only so much you're going to get out of ~207 cu. inches. I'm sure there's plenty of people on this forum and others that have dumped a good amount of money into the exhaust on these trucks chasing a certain sound that just can't be obtained from a small motor. To me, that money can be put to better use.