ACT Exhaust

[notaping]

Anyone got experience of ACT exhausts - in particular big bore (with rear box) vs standard ACT rear box? Not too bothered about extra HP, but is there much difference in the noise between the two?

My car's currently got sports tails and de-catted. I want to calm it down a bit, but don't know if it's worth the extra for the big bore system.

Cheers.

[pmessling]

Putting the cats back in makes a difference.

I put them back in to help reduce the exhaust smell which can get rather over powering

[notaping]

The cats - good idea, I'll put those back on, but any opinions on ACT systems would be much appreciated. I'd still like to try to get it down a bit.

Strangely - I've never had any problems with exhaust smells in the car and it's been straight through for many, many years. May be a dodgy boot seal?

Edited by notaping on Wednesday 4th December 19:10

[Supateg]

I went from sports tailpipe to the act big bore quiet system with silenced tail pipes also.
A lot more comfortable noise wise, the droning at cruise used to give me a headache! Still a pleasant sound, overrun is no longer like an AK47

I have some videos of the sound, pm me

[Robscim]

I've got the ACT big bore exhaust and manifolds. It sounds lovely and doesn't seem over-loud, however on a long run, you notice it when you stop!!!

Having said that, I've driven Aberdeen and back and it wasn't too terrible!!

I'm in West Sussex if you want to have a listen - I'm not sure a recording would be much help!

Cheers

Rob

[notaping]

Thanks Rob. Supateg sent me some vids with big bore sounds. Played through a pair of excellent JBLs. Sounds lovely. Very real, and very useful. Ta.

Edited by notaping on Thursday 5th December 12:26

[Byker28i]

I've got the ACT quiet system, now 16 years old and still fine, despite Berk in a Merc best efforts to ram it. It's coupled to the tuned length manifold they did at the time, a work of art.



It's got extra silencing in the tailpipes and center pipes like their big bore system. I think the difference is mine is 2.5" and the big bore is 3" piping?

From my testing, Cats give 8-10db noise reduction by seriously heat the gearbox/clutch/cabin.

The big difference is the road clearance at the rear and less weight compared to the big box system.

ACT do some silencers as replacements for the cats
https://www.actproducts.co.uk/product/sjd02a-silen...

but I've not found I've needed it. 106db at the tail pipe at 5k revs, I have fitted extra/new heatshielding and extra silencing in the cabin.


Note. Fumes in the boot means the boot isn't fitted right. I had this after the chassis off rebuild and it just need the latches adjusting, so you have to give the boot a slightly harder slam...

[Byker28i]

I should add, ACT Pre sales advice and after sales service is second to none.

[notaping]

Yeh! - clearance is a concern. I've already rubbed through both sports tail boxes and had them repaired.

Options, options. . . .

It's going to be a spring upgrade - so plenty time to mull it over.

Thanks all.

[Byker28i]

For me, obviously I had the issues with the SP exhaust, got ripped off, but also the ground clearance. Bearing in mind I run my car slightly raised and soft, as a grand tourer, it sat low at the back which was an issue with speed humps etc



Another reason I liked the ACT sports offering

[MarkwG]

Byker28i said:

For me, obviously I had the issues with the SP exhaust, got ripped off, but also the ground clearance. Bearing in mind I run my car slightly raised and soft, as a grand tourer, it sat low at the back which was an issue with speed humps etc



Another reason I liked the ACT sports offering

Thank you, that's the same direction I'm going in with mine, it does long trips, not really track days: do you have an idea of how much lighter the ACT rear section is compared to the standard? I'm working on the "every little bit helps" theory.

Edited by MarkwG on Friday 6th December 17:03

[notaping]

That's a similar setup to mine, indeed I grind the bolt heads on the chassis plate at least once a year when I'm caught out by a high speed compression.

I like the idea of the big bore sports pipes. They have the benefit of muffling in the tails - which my current standard sports don't.

[Ulrich]

I went ACT 200 cell sports cats with silenced bullet type big bore mid section followed by big bore sports tails. Not obnoxious and too loud but just right - in my mind anyway. Standard box was rotten. Loads of pops on the over run but no bangs. All in all very pleased with that.

[Byker28i]

MarkwG said:

Thank you, that's the same direction I'm going in with mine, it does long trips, not really track days: do you have an idea of how much lighter the ACT rear section is compared to the standard? I'm working on the "every little bit helps" theory.

Edited by MarkwG on Friday 6th December 17:03

Sorry been without power for a while...
From memory it was in the order of 5plus kg, but I can't remember exactly, sorry.

Extra silencing in the tailpipes


and obviously the road clearance is better

[Byker28i]

Any excuse

[MarkwG]

Thank you, that's very helpful: every kilo counts, & it looks like it'll mount higher into the cut outs too, which is neater.

[FarmyardPants]

It does look better when the tailpipes align nicely with the cutouts

[notaping]

Pulled the trigger on the ACT Big Bore system (SJ10C) - as in Byker28i's first pic. Won't be fitting it 'til spring, but beginning to fill the 2025 parts bin. Just stocked up on oil and will be replacing the filter holder. Noticed some marks on the seal face which allow some weeping - which is annoying.

Also found these https://www.amazon.co.uk/dp/B07XQSBW7Q/ref=pe_2706... to replace the boot switch (12 for £6 - plenty of spares) while I'm enamelling the badge. Seems a bit more reasonable that Motaclans £29 for one !*?

Thanks all for your input re the exhaust. I'll post some pics when it's fitted.

G.