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View Full Version : 3.2 Exhaust, decat, high flow cat...



Lankstarr
02-07-2007, 06:37 AM
I have recently been experimenting with a new set up on my 3.2.

I started off with decat and new back box:

Result was too loud for me and probably most tracks, housing estates etc! EAch back box will obviously make a huge difference to the overall sound but my opinion is that what ever sound the back box produces is magnified by nearly X2 by removing the cats. From what I hear this is not the case with 3.0s - they respond completely differently to exhaust mods.
Sound was beautifully raspy at top end but unfortunately too loud to hear the engine change into VTEC and I think that the original engine noise that attracted me to the X was somewhat lost. Weighing up pros and cons I guess.

Next I tried the same exhaust with the original cats back on - what a difference! Again I'm really please with the noise at the top end and the car sounds fantastic when booted, it lost the raspyness that I had with the DCAT pipes but I gained back my VTEC change.
The current set up is still very loud at idle and lower in the rev range so I think I can definitely say that this report is based on any differences shown with an already very loud backbox.

Unfortunately I have no idea what dbs the exhaust was putting out in each scenario.

The car is much more driveable as it is now but there is still more playing required to get to the optimal sound experience for me. I want to be able to hear a bit more of a rumble at low revs but totter around with felling chavish whilst still maintaining the increased volumes at the higher rev range which sound awesome. Don't want much do I!?

The next step is to put the original back box back on with the DCAT pipes and see what this sounds like. I'm thinking that this will increase the standard sound levels which are harmonious, giving that extra bit of grunt and feel. I will report in due course!

Whilst the new backbox is off it will be "retuned" and some high flow cats fabricated which will give yet another possible sound combo.

I will try to get sound clips as it is now, and also with teh last two combos but I failed with all different equipment with the first set up as it was so loud it just distorted when I played it back :O( Maybe my recorder guy shouldn't have been stood in a tunnel :laugh:

Luke

Kevin
02-07-2007, 06:46 AM
I've been adjusting my exhaust over the weekend. You may find my efforts of interest.

I'll take some pics tonight and explain more in detail.

Lankstarr
02-07-2007, 07:08 AM
hmmm sounds interesting!

I love the standard noise an NSX makes so want to ensure that any "upgrades" I do for performance do not take anything away from the car!

With no garage of my own to tinker with anything these adjustment are very time consuming and costly for me... if I can end up with a sound I am happier with than the standard sound it will all be well worth it!

AR
02-07-2007, 08:48 AM
Funny enough I had a bit of thinkering myself with a two in to one y pipe and two muffles, the results is loud, high pitched, low rumble at idle and what a rush!

Cheers,

AR

Lankstarr
02-07-2007, 09:31 AM
sounds like you need to be coming up for the tunnel run Ary :laugh:

Trouble with mine is it is my only car so it gets a bit much if you're doing 8k a year, it's a delicate balancing act, I'll get there in the end!

AR
02-07-2007, 11:08 AM
I wish I had the time mate! As you say is not bad if you do not use the car everyday.

Cheers,

AR

Lankstarr
02-07-2007, 11:27 AM
I'm hoping to have weekends a lot free'er soon so maybe we can have a mini tunnel run down with Amo by you:laugh::D

TheQuietOne
02-07-2007, 11:51 AM
:O( Maybe my recorder guy shouldn't have been stood in a tunnel :laugh:

I still have tinitus mate! ;)

TheSebringOne
02-07-2007, 01:28 PM
Pipes, pipes, pipes and the smoking ban came into effect yesterday! ;) Like & unlike Luke, I would love the idea of a back box, from cat back upgrade like Paul (Sennihna) with the slash quad ends- yum yum, but I only do less than 2K pa & its not my daily drive, so no real point in tinkering for now :(

Senninha
02-07-2007, 01:28 PM
I love the standard noise an NSX makes so want to ensure that any "upgrades" I do for performance do not take anything away from the car!

Hi Luke,

Well purely from the end of the phone it is remarkably quieter with the Cats back in, but has retained a nice top end sound. It will be interesting to see what the changes make to your R/Roll figures should we ever repeat the exercise.

You mentioned that whilst running the t/pipes it was running rich and less smoothly ... supporting the tuning info I had been given for the 3.2 ... has this now improved with the Cats replaced?

regards, Paul

Lankstarr
02-07-2007, 02:09 PM
I havnt' noticed any smells suggesting rich running but it was when Matt followed me (brave thing) that he said I was chucking out a lot of crap.

It feels a lot better now, more of a kick when VTEC comes in and certainly doesn't feel slow.

It's hard for me to compare with teh standard set up now as I was without car for 3 weeks for my hols and before that running anopther 3 weeks with the DCAT set up. It's been a while since I've driven her std so it hard to remember.

If I could have a "race" with Matt or someone that would be the real test for me as we were absolutely neck and neck when running as standard. Even if I did get a 15 bhp gain from exhaust and air box I doubt it would be very noticeable in a staright line but I'd love to try it out!