New 3'' Manta exhaust,does it quieten down after carboning up

[Jackel]

Ok guys! 1 3/4 headers or 1 7/8?
I have a custom tune & otr. Not looking to cam or supercharge.

 

[abuch47]

3 quarter

 

[Strattos]

It might be a characteristic of the electric Bi-modals.
I haven't noticed it on the vacuum bi-modals on an E3 Maloo.
A cold start in the garage with bi-modals open shakes my house and rattles the windows in my neighbours house.

Hehe, can certainly understand how it would! As I said earlier, I only leave them closed for early starts. When I leave work at the end of the day with a stone cold motor and the bimodals open, the rear view mirror vibrates for a little bit until the revs drop as the motor warms up. Sounds magic, but too loud for the neighours imo - hence the BM option.

Jackel, for me, if you have the bimodals fitted, you shouldn't have a drama with noise. Even with them open, cruising at either 60 or 100km/h I honestly cannot hear the motor at all - I hear it a little at 110km/h, but only just. If you're going through the gears in normal traffic under 60 in sedate driving (mines manual), it is louder at points in the rev range, but shut the bimodals and it makes a difference there as well to the point where people around you, and you in the car, won't really notice a massive difference compared to stock system with fuse pulled out.

Agree with abuch re going the 3/4.

 

[Jackel]

Hehe, can certainly understand how it would! As I said earlier, I only leave them closed for early starts. When I leave work at the end of the day with a stone cold motor and the bimodals open, the rear view mirror vibrates for a little bit until the revs drop as the motor warms up. Sounds magic, but too loud for the neighours imo - hence the BM option.

Jackel, for me, if you have the bimodals fitted, you shouldn't have a drama with noise. Even with them open, cruising at either 60 or 100km/h I honestly cannot hear the motor at all - I hear it a little at 110km/h, but only just. If you're going through the gears in normal traffic under 60 in sedate driving (mines manual), it is louder at points in the rev range, but shut the bimodals and it makes a difference there as well to the point where people around you, and you in the car, won't really notice a massive difference compared to stock system with fuse pulled out.

Agree with abuch re going the 3/4.

Why the 3/4?

 

[Jackel]

3 quarter

Why?

 

[Strattos]

From what I've read and what I've been told when researching my mods, if you're staying NA and not going stupid with cam/head upgrades there's no real benefit.

Apparently the smaller headers will also give you a little more bottom end with no noticeable difference up top without other mods, but to be honest a lot guys I spoke to also said you'd be hard pressed to notice the difference seat-of-the-pants in terms of any bottom end loss.

Unsure if there's much of a cost difference? That could be another factor? Could also have an impact on how loud your system is and risk of drone (guessing here). Just my two bobs worth though and I'm certainly not an expert. Just what I've read and heard through research.

 

[dimetime]

Why?

Only go 1 7/8s if your charging it, 1 3/4s is plenty, in my experience, fatback size is everything to do with how loud it is as I had 1 7/8 headers and a 2.5 inch catback and my new car has 1 3/4 with 3 inch and my new car with the 3 inch is much louder!

 

[PeteSS]

Only thing I have noticed, and I'm being pedantic here, is at cold start up in the mornings, even with bimodals shut, sometimes that initial fire can be quite loud - seems intermitten, so not sure what's happening there. The bimodals are definitely working, as when this happens and I open them to see if they're working, it definitely gets louder. THis is probably a really stupid question, but can it have something to do with where pistons are at when you shut the motor down the night before?

From what I have read in other threads, on start up the bi modals actually open (whether in open or closed position), as they open when there's no power going to them (someone may correct me on this). i noticed it on a mate's GTS too. Even on "Touring mode" which shuts the bi modals, it's as loud as F*** on start up. I'ts one of the reasons i haven't put the factory Bi modals back on mine as it's mainly on start up that i need to quietn it down

 

[MY17DIR]

Why the 3/4?

Did you read all parts of the article i linked?

 

[lmoengnr]

1 3/4" or 1 7/8" headers and high flow cats wont be much different, basically just splitting hairs...
As soon as they are fitted, you'll gain torque all the way through the rev range, even before a tune.
The factory headers and cats are the biggest restriction to performance.