Porting 4.5L Inlet Manifolds - Is it worth doing?

[Byker28i]

ukkid35 said:

The things I do like about TVR's AJP8 manifolds is that they are incredibly light, and far less absurd than what they employed in the Chims and Griffs - all that heat radiated in the front of the engine bay!

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I don't remember the manifolds being that light, certainly not compared to the ACT ones. I think I've shaved a few kgs with the complete exhaust system, certainly road clearance losing the large rear box

[julian64]

Some confusion here, ACT do a large back box and straight through pipes. I bought the former because I like racetracks

[Byker28i]

julian64 said:

Some confusion here, ACT do a large back box and straight through pipes. I bought the former because I like racetracks

As yes, they do now, I have the quiet sports system, silencing in the long centre pipes, a small silencer before each tail pipe and more in the tail pipes. Smaller, lighter

[julian64]

Byker28i said:

julian64 said:

Some confusion here, ACT do a large back box and straight through pipes. I bought the former because I like racetracks

As yes, they do now, I have the quiet sports system, silencing in the long centre pipes, a small silencer before each tail pipe and more in the tail pipes. Smaller, lighter

How quiet is quiet? Brands is 95Db and I only just get in that with my giant backbox.
Surely two small decat sized tubes in a straight exhaust is not going to save you down the back straight? The silencing in the long pipe can't be very big if you still have the metal undertray on?

[gruffalo]

Byker28i said:

julian64 said:

Some confusion here, ACT do a large back box and straight through pipes. I bought the former because I like racetracks

As yes, they do now, I have the quiet sports system, silencing in the long centre pipes, a small silencer before each tail pipe and more in the tail pipes. Smaller, lighter

I jade the same as you Byker, mine used to read 113db at noise test so I had to use track cans all the time on track, ended up keeping the straight through silenced decat pipes and using the ACT big back box, not 95db ish, a lovely noise and no horrible cans on the back.

[Byker28i]

julian64 said:

Byker28i said:

julian64 said:

Some confusion here, ACT do a large back box and straight through pipes. I bought the former because I like racetracks

As yes, they do now, I have the quiet sports system, silencing in the long centre pipes, a small silencer before each tail pipe and more in the tail pipes. Smaller, lighter

How quiet is quiet? Brands is 95Db and I only just get in that with my giant backbox.
Surely two small decat sized tubes in a straight exhaust is not going to save you down the back straight? The silencing in the long pipe can't be very big if you still have the metal undertray on?

106db at 4.5k revs, 98db with trackday cans on.
I managed 88db for Thruxton once by putting the cats back in and the trackday cans, but it was a bit strangled.
Noisiest I could make it with backfires, lots of revs etc was 116db.

Mine looks like:

[Byker28i]

I had the Silverstone performance rear box, had terrible problems with it. Badly made, badly fitted, damaged my rear valance, never made the 98db as claimed, then discovered the test car had the cats fitted, when they claimed it was 98db without cats.

I had to jack my suspension up another 40mm so there was 110mm clearance from the exhaust to the road to give me any chance of going over speedhumps, it came back with only 70mm and the car looked terrible and handled poorly as well.

That cost me a lot of money. Went to ACT and never looked back. Current system is 9 years old and still fine