Jump to content
SAU Community

Recommended Posts

Is 3" cat back big enough for 240-250rwkw?

I hae a 3.5" SS Kakimoto catback but now with the highflow a little noisier and around 2-2500rpm if loaded a little up a hill it gets a little droney.

Was thinking 3" mild steel might be quieter. It has 2 mufflers on it.

  • Replies 45
  • Created
  • Last Reply

Top Posters In This Topic

When I first got my car was told it was 3" from the cat back into a jasma muffler and compliance cat and it was a tad loud but not booming loud. Sounded just right.

Last weekend I installed JJR split front/dump pipe and Xforce high flow cat and also noticed my exhaust is 3.5" from the cat back into some kinda resonator then into the jasma muffler and now its sounds good. Not loud at all and not quite. Id prob be a lil under the DB limit and I love it.

I have the exact same system as you and I can tell you that its way over the db limit. I got epa'd for it and had to fit a standard system for the test, which still came in at 90.4 db for a 90 db limit. The standard system was a lot quieter than the one you have.

  • 4 weeks later...

Anyone know if a silencer will get rid of a bit of drone.

My kakimoto 3.5" is a little droney when you back off or go up a hill pulling 2500rpm.

Thinking of making a silencer to add for longer drives. Will this reduce the drone at all?

It has got a little louder since the hi flow turbo.

It has a big centre muffler..and rear

I'm running the same exhaust on the R32 gts-t. It is indeed very quiet and full stainless steel. The exhaust is 3.5".

For what it's worth I run an HKS Silent Hi-Power system and was very surprised at how quiet it was. The 'Silent' in the name isn't just a marketing ploy. It seems they are rated at 98dB but I would be very surprised if it's louder than 90dB.

This is on a GTT with HKS dump and Front pipes as well... x-force cat. It sounds wicked as hell when you open it up. Surprised no one else is running this system.

  • 1 year later...

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • Oh, that's grim. Something bad has been happening there.
    • Put an endoscope down the hole and saw this. Not quite all around the bore but a good 60% at least. Chin to the chest and towards further disappointments I guess.
    • 2 does "sort of" applies, maybe......but looking at what parts would be needed for the swap to get engineered, registered, and insured, and basically that's everything under the car, the modifications the make it legal would be problematic and horrendously expensive, all for a street car that just cruises around and hits a few twisty roads on the weekends Also, from looking at the NSW rules and Regs, with all modifications that is required just to make the car safe and not twist itself to pieces, and then actually get registered for street use, may still be impossible nowadays As for 1, when you add in a fresh engine, fresh transmission, rear cradle and diff, tailshaft, suspension, brakes, cooling, and all the other fabrication required, your probably looking at up to $100k to do it right, all for a 20 year old MX5 that is over engineered and you would never be able to actually use the power it has on the street, much like your beastie, which I love, but you actually track that thing and can use all of its powers in anger, in a safe environment  Hell, the old Bogan Cruise Ship had more power than I could use on the street, and in hindsight, I went a bit silly on that thing, it didn't really need the 500hp it had for what I actually used the car for, it was fun, but basically unusable on the street if you value your licence  As for cams, yeah, I'll probably book it in for them to get installed and tuned soonish, like next month after MX5 Mania are back at work....... and yes, I've already sent a email to bin the turbo quote and quote instead to install cams and a new Fluidampr balancer that will suit the 2.5 better than the OEM 2.0 balancer that is swapped over for the 2.5 install, as the balancer needs to get pulled to time the cams it's a while your in there sort of thing I did think a bit about flex fuel for a laugh, but being na, and no where really around locally anymore to get E85, I've binned that idea, so no sweet sweet corn smells are set for the car I wish E85 was more of a standard fuel, it's better for the environment, better for tuning, plus that sweet sweet smell we all love As for fitting in the family, that's not needed, as everyone in the family already owns a car that can seat 5 humans comfortably enough, the MX5 is "my toy" As for buying a car that is already built, nah, I would rather pick and choose my parts, I enjoy the process, and in the big picture, the additional cost is well worth the enjoyment, and the occasional frustration, I get out of doing it, albeit with other people spinning the spanners, and me, just paying the invoice 🤣
    • Excuse me, but 2) does apply 1) Would also apply if you consider how much is spent in the alternatives. Also there's the option of 3), buy one pre-built that you can put your family in (it's me, it's my car)   That said, I went on a ~500km drive the other day. I didn't use anything more adventurous than 3rd/4th gear at about ~3000RPM and 50% throttle and I was going as fast as anyone has any sense doing on a public road, with enough grip to the point where I didn't want to go any faster. I was obviously under the limit of the current car etc etc. MX5 with 2.5 N/A to achieve the same speed would be more fun for any road scenario. Maybe consider cams. I wouldn't boost it. The use case is just not there and it won't actually make the car more enjoyable unless you really do plan on wringing gears from 1st to 3rd (at least) at 100% WOT on a public road to 150+kmh.
    • Great if: 1. You had all of the money for everything else that is required  2. Lived in a country where you could actually do this and drive it legally on the road Sadly, neither applies to me As for the turbo, I am having second thoughts, mainly for engineering/registration legality reasons and insurance  Not saying I've finished doing stupid things that I probably should do to the MX5, but boost, and V8 engine swaps isn't on the cards Strange, but true 
×
×
  • Create New...