1.6 exhaust questions

[tails]

Hi folks,

I'm thinking about upgrading the exhaust from the cat back on my NA6. I'm not sure whether to go stainless or mild steel and was hoping folks could perhaps make some recommendations.

I'll be getting it fabricated and I have had stainless systems made in the past for other cars but I'm leaning towards mild steel due to wanting to eliminate as much as the rasp as possible (and it's a bit cheaper) however I like the look and corrosion resistance of a stainless system. I'm just wanting to confirm if there is that much of sound difference between stainless and mild? Are there any other advantages to either material that I could be missing?

I guess I'd be looking at 2.25" diameter? This seems to be what I've read everywhere else.

I should note that I already have stainless headers.

[NitroDann]

A well designed stainless system should be completely devoid of rasp and sound excellent.

I recommend quality stainless systems for longevity and resale value.

You actually want 1-7/8th exhaust size, but its not really viable so you should go for 2".

Dann

[tails]

A well designed stainless system should be completely devoid of rasp and sound excellent.

I recommend quality stainless systems for longevity and resale value.

You actually want 1-7/8th exhaust size, but its not really viable so you should go for 2".

Dann

Thanks for the prompt response, NitroDann.

Any particular reason for the 2" recommendation instead of the 2.25" I've read a lot elsewhere? Is it mainly because the muffler and high flow cat off more performance than the tubing itself?

[NitroDann]

Even 2" is too big in terms of the ideal size for outright performance.

Across the rev range 1-7/8ths would be ideal. 2.25" will only leave midrange on the table and in addition is much harder to get a sweet note from.

Dann

[pcmx5]

Dann has much more practical knowledge than me but I agree that many MX owners want too big a diameter pipe and from what i have heard his work is fantastic.

If you want to save money going 2 inch press bent(which actually sightly reduces the diameter on the bends) in mild steel and with a stainless offset straight though rear muffler will give a good combination of power and sound.Have had a lot of cars do before and after dyno runs so know it works.However as always the gains are a bit dependant on the condition of the exhaust you are removing especially the cat.

The size of the taipipe is critical to the note ,don't go too big.Good luck.

Peter.

[91BRG]

2 inch seems to be the sweet spot for 1.6 stock engine, anything bigger is for modified/turbo.
I went with 2 inch press bent mild steel, into a mazdaspeed 2 inch muffler. Sound is beautiful, no rasp or droning.
whether its press or mandrel bent i doubt would make any noticeable difference on a stock 1.6 engine. But the difference will be double the price between press bent mild vs mandrel bent stainless.
for reference, I am running 4-1 mazdaspeed header > magnaflow 2 inch hi flow cat > 2 inch press bent mild steel mid pipe (no hotdogs) > 2 inch mazdaspeed muffler. With intake and ecu I have 86rwkw on MX5 mania's dyno. My exhaust is dead quiet on idle and cruising and only opens up at WOT. Can hardly tell it's modified.

[pcmx5]

Glad you are happy with it BRG and they certainly sound great ! It is nice to have a quiet cruise and a bit more when the boot is put in!!You are right about the cost and for the midpipe which gets hot and doesn't collect moisture like the rear muffler does mild steel is cost effective and will last especially if it is aluminised tube..
A more meaningful output figure would be before and after on the same dyno ex. I have seen increases from 63-4 RWKW to 70-74 on 1.6's on Dyno Dynamics with a cat and exhaust,no ECU change(but again a lot depends on the condition of the exhaust being taken off and some cars are just better than others.As always dyno's cannot be compared but before and after on the same one can!

Must say though that the quality of Dann's work is hugely impressive and for those near him he would have to be the go to man.

Peter.

[tails]

Thanks for the tips guys. Might update the thread once I've got something on.

[Alex 2550]

Dann's going to do mine when i take the car to him for some other more serious work, he really knows his stuff and quoted me on stainless which surprised me because i said i don't want rasp, some things are better left to the experts i guess.
in the past i have always opted for mild due to the common thought of "it sounds better than stainless".
i don't get any kick backs or anything for saying this but i would contact Dann. His work is well known to be of high standard, he knows and takes pride in what he does and his price was good for the quality and passion you get which is a bonus.
he is also a sponsor of the forum which i think is forgotten some times.

[tails]

I probably would have if the drive wasn't so far from Adelaide to Sydney.

[speed]

Pretty sure he could send you one. Think Richard had his exhaust freighted to him.
Worth checking out all the same.

Sent from my GT-I9506 using Tapatalk

[tails]

Ended up with a 2" mandrel bent stainless system with a 14" resonator, 200 cell cat and straight through muffler. Sounds exactly how I wanted it to. Eliminated most of the rasp, and is quite a bit deeper than I thought it would be. A few little pops and bangs during over run as well which is a bit of fun. No drone what so ever, can't even hear it as cruising speeds (50 or 60 mostly).

This was in addition to the 2" stainless headers already on it.

The video makes it sound a bit more tinny than in person, but here's a quick clip anyway;