Cutting down on Engine Noise 2.7

[DrunkenSlug]

Hey there! The engine noise around 2k is just insane. 2200? Can't hold a conversation. At least in the 2.7l.


However, this took at least 30% if not 50% of the noise from the engine away. Its not quiet as a Cadillac by any means.. But you can easily hold a conversation with it done like this.

I did the entire hood with Killmatz sound deadening (make sure to use a roller so it doesn't sag).

Then you'll want to go inside, take the entire dash apart, and seal that entire firewall up. Make sure you get the top (near the vents) with an entire layer just like the roof. I forgot to take a pic with the dash apart, but here's a pic from inside the cabin footwell. This is how far I went down. Now imagine that, all the way to the very top behind the dash. Behind the HVAC, behind the radio (see my other thread on overkill radio, amp, sub, 6 speaker setup). Above the pedals, on the sides, everywhere behind there. T30 and 12mm to take the dash apart, very simple. I just left it hanging on the wheel and reached back there to do the entire process.

Products I used

https://www.amazon.com/dp/B0751G6TMV?tag=roxor-20

Amazon.com: Car Sound Deadening Roller Metal Installation Tool 3 Pcs for Auto Noise Roller Car Sound Deadener Application Installation Tool Rolling Wheel Interior Accessories : Automotive

Amazon.com: Car Sound Deadening Roller Metal Installation Tool 3 Pcs for Auto Noise Roller Car Sound Deadener Application Installation Tool Rolling Wheel Interior Accessories : Automotive

www.amazon.com

Scissors

 

[captwheel]

Do you have an enclosed cab, or is it open air
Thanks, Phil

 

[DrunkenSlug]

Do you have an enclosed cab, or is it open air
Thanks, Phil

I have the all weather cab. I’ll be swapping to a full cab at some point in the future.

 

[Bob R1]

I am greatly surprised that your machine is that loud. My 2024 is not annoying at all. (Date Corrected)

Bob R

 

[DrunkenSlug]

I am greatly surprised that your machine is that loud. My 2014 is not annoying at all.

Bob R

Really? I mean, I’ve got the 5.36 gears so it’s likely higher rpm on average. My roxor does most of its driving on the road about 2200rpm until I swap to 4.10 next month

 

[Bob R1]

The Full Cab may be the difference in noise. I have a Windshield, Roof, and Rear Bulkhead. NO DOORS so far.
My Bad above on 2014, now corrected. I have a 2024, and it has the same 5.38 Gears as yours.
Wind noise may drown out any engine noise on my machine.
It will be interesting to see how your 4.10 gears turn out. Keep us posted on progress. The best gears for a 2.7 should be in-between 4.10 and 4.88, and tire height needs to also be a factor in the gear selection. With tall enough tires the 5.38's are working ok for some on here. USMC comes to mind with his 35's.

Bob R

 

[DrunkenSlug]

The Full Cab may be the difference in noise. I have a Windshield, Roof, and Rear Bulkhead. NO DOORS so far.
My Bad above on 2014, now corrected. I have a 2024, and it has the same 5.38 Gears as yours.
Wind noise may drown out any engine noise on my machine.
It will be interesting to see how your 4.10 gears turn out. Keep us posted on progress. The best gears for a 2.7 should be in-between 4.10 and 4.88, and tire height needs to also be a factor in the gear selection. With tall enough tires the 5.38's are working ok for some on here. USMC comes to mind with his 35's.

Bob R

Seems like there’s enough power to turn 4.10 even without a tune. I never feel down on torque/power. I just run out of gear wayyyy soon. Thinking with 4.10 and 32-33 I’ll be spinning 60 at around 1800-2000 which would be ideal for me. Then I’d still be able to off-road. Figure I’ll toss both OX lockers same time.

Wonder what usmc speed is at 2k with those 35’s

 

[USMC]

Good with your RPM approximation Drunk! With my 35s I still have plenty of torque at 2400 RPM. That is with the 5.38s.

I am at 2400 at 60 with my 35s. And I can still pull away. Around 46 MPH at 2000 RPM.

My noise with the doors off come from my tires at a certain RPM, a high pitched Hum.

 

[Gabe]

Nice. You doing front and rear Ox? I got my last year was going to put the rear Ox in but the dealer wouldn't do it " warranty "? At some point will get that done but not high priority right now.

 

[DrunkenSlug]

Good with your RPM approximation Drunk! With my 35s I still have plenty of torque at 2400 RPM. That is with the 5.38s.

I am at 2400 at 60 with my 35s. And I can still pull away. Around 46 MPH at 2000 RPM.

My noise with the doors off come from my tires at a certain RPM, a high pitched Hum.

What rpm do you tend to run? Mine lives around 2200 with my driving. Wondering if I’m damaging it, seems pretty high revving noise wise for this engine. But otherwise you aren’t really getting anywhere lol. To fit the 35s you had to have at least a level kit or something I’m guessing?

 

[DrunkenSlug]

Nice. You doing front and rear Ox? I got my last year was going to put the rear Ox in but the dealer wouldn't do it " warranty "? At some point will get that done but not high priority right now.

That’s the plan, figure do both. Eh, warranty was only like 3k miles anyways wasn’t it? I deleted my cat and egr the day I picked it up anyway. If you wanna sell that rear locker, let me know!

 

[USMC]

What rpm do you tend to run? Mine lives around 2200 with my driving. Wondering if I’m damaging it, seems pretty high revving noise wise for this engine. But otherwise you aren’t really getting anywhere lol. To fit the 35s you had to have at least a level kit or something I’m guessing?

I run 2200 to 2400 all the time because of my main roads that I drive on., 50 to 55 MPH. I would check all my oil fluids if I were you. I need to do that also.

I was trying to keep my costs low and still make the Roxor street legal. My tires are only speed rated at 50 MPH but they fit the stock wheels. To keep the tire from rubbing or hitting my frame I did the 2-inch wheel spacers all around and the 1.5-inch lift on the front and rear. If I traverse a deep and narrow ditch at a 45 degree angle my rear tire will rub the lip of my tub.

 

[DrunkenSlug]

I run 2200 to 2400 all the time because of my main roads that I drive on., 50 to 55 MPH. I would check all my oil fluids if I were you. I need to do that also.

I was trying to keep my costs low and still make the Roxor street legal. My tires are only speed rated at 50 MPH but they fit the stock wheels. To keep the tire from rubbing or hitting my frame I did the 2-inch wheel spacers all around and the 1.5-inch lift on the front and rear. If I traverse a deep and narrow ditch at a 45 degree angle my rear tire will rub the lip of my tub.

Dude if that’s the case I may ditch the idea of the rough country lift and do the same 1.5” you did and run 35s as well…. Think it would still have enough torque (especially pre tune since they can’t yet) with 4.10s? With the 29s and 5.38 this thing would climb vertically up idle in 5th it feels like haha. That would put me around 75 mph at 2200 rpm if I’m doing it right. Which is ideal, I’d be cruising 60 around like… 1800?

 

[USMC]

Drunk, you would be closer at 2300 RPM at 75 MPH with 4.10 gears. I believe 5th gear tranny is a .78 ratio.

I never use first gear except in the yard with my granddaughter, I think a snail is faster. Oh, and pulling small stumps from the yard. At 55 with 5.38 gears, I still have plenty of torque to pull away from vehicles.

 

[Longslyde]

Here's a calculator for those that want to see exactly where rpm is is each gear with size of tire and rear end ratio. I use this all the time for different projects.

Drivetrain calculator

Transmission data:

Gear Ratios

1st gear	4.00:1
2nd gear	2.09:1
3rd gear	1.38:1
4th gear	1.00:1
5th gear	0.79:1

Reverse 3.52:1
Transfer case low = 2.46:1

Fill in the numbers in the approriate areas and it will spit out all the data you need.