ATC or CF?

[motul1974]

What's the general consensus from those in the 'know'. A set of these CF's long primaries

[motul1974]

[motul1974]

...or




I prefer CF's lovely Y piece and the ability to use the old cat if needed at mot time, but, looking at how it meets the non cat y piece, is this not a point where the exhaust effectively slows down by entering such a BIG area?? Where as the ACTS looks like (to me) as if it might keep velocities up and out of the main system better?

I'll need manifolds early next year as I sold the originals. I had planned CF's tuned and equal set up, just not sure I can justify or really afford them. I'm sure I could get my EXTRA big man maths calculator out if I needed to, but thought if look at the cheaper options.

[BIG DUNC]

I have ACT and think they are great.

From what I read on here, Clive Ford are preferred, but are also more expensive.

[Andav469]

motul1974 said:

...or




I prefer CF's lovely Y piece and the ability to use the old cat if needed at mot time, but, looking at how it meets the non cat y piece, is this not a point where the exhaust effectively slows down by entering such a BIG area?? Where as the ACTS looks like (to me) as if it might keep velocities up and out of the main system better?

I'll need manifolds early next year as I sold the originals. I had planned CF's tuned and equal set up, just not sure I can justify or really afford them. I'm sure I could get my EXTRA big man maths calculator out if I needed to, but thought if look at the cheaper options.

Depends what power you are looking for ACT pipe size is 40mm Clive F is 45mm

[lancepar]

SHOWTIME



Hey BD, do yours tinkle when cooling down

[motul1974]

Circa 300hp from my v8ds 4.6

[phazed]

Until someone does a back to back performance comparison, we can only guess at performance gains.

Personally on my 5.5, the ACT system gave about 12 more bhp and moved the max power up from about 5,250 up to about 5,750 rpm.

That was over a standard system.

[Classic Chim]

Defo adds power.
With no other mods I took a Catted Chim 450 that had consistently run 13.1’s for the quarter mile, added Clives catless Y Piece and I managed 12.7 fairly consistently so removing cats gained about 10 Hp I reckon.
If Peter gained 12 from the Act manifolds as he already runs de Catted there’s clearly gains to be had.
If running standard heads I think that will be the limiting factor.

[motul1974]

Heads are all flowed and bv, it's more a question of theoretical 'best' head option between the above options. As often a the case, getting back to back testings in near impossible.
I simply liked the CF system to look at, but suspect ACTs copy of Peninsula racing system 'probably' flows better? Especially as in cost comparison there's money left over to have them ceramic coated when compared to CF's cost.

I fully appreciate I may never notice the difference, but it's worrying about these little things helps me enjoy the Christmas holidays more! lol

[900T-R]

Can't help thinking the extra weight on the spaghetti type of manifolds alone would offset any further gains compared to the ACT ones... - it seems that the Rover isn't overly fussed over breathing out through equal length primaries, the reports I've heard claim actual bhp differences are in the low single digit regions for a typical 300-ish bhp RV8.

[Andav469]

motul1974 said:

Heads are all flowed and bv, it's more a question of theoretical 'best' head option between the above options. As often a the case, getting back to back testings in near impossible.
I simply liked the CF system to look at, but suspect ACTs copy of Peninsula racing system 'probably' flows better? Especially as in cost comparison there's money left over to have them ceramic coated when compared to CF's cost.

I fully appreciate I may never notice the difference, but it's worrying about these little things helps me enjoy the Christmas holidays more! lol

I doubt there will be any difference in power gain between the two systems at 300bhp, but the noise is different, the ACT manifolds give a more bass low down noise.
This is from a side by side comparison of Clive F Manifolds and Y Piece v ACT (but not the equal length version of CF)

[motul1974]

Lol...you're probably right, the reality of it will be sound and what they look like!
Id pretty well decided to go for the ACT system until I got an early Christmas present of the Lloyd brothers book on RV8 tuning, then the full fat CF's tuned system (great pucs of it in the book) reappeared in my head....then the idea of keeping it cheaper! lol

[BIG DUNC]

lancepar said:

SHOWTIME



Hey BD, do yours tinkle when cooling down

Yep

[Zener]

TBH as much as I like CFs work, there are certain aspects of the ACT manifolds I prefer the secondary bore/sizing for example

[Andav469]

Zener said:

TBH as much as I like CFs work, there are certain aspects of the ACT manifolds I prefer the secondary bore/sizing for example

By contrast of opinion, I preferred the look of the CF in my Chimaera

[phazed]

[motul1974]

Andav469 said:

By contrast of opinion, I preferred the look of the CF in my Chimaera

That does look good all SHINEY

How much work does it involve to keep them that way?

[Andav469]

motul1974 said:

That does look good all SHINEY

How much work does it involve to keep them that way?

That’s it, they stay that way, when they were new, they were silver, once used and after a few heat cycles, they go a straw colour as in the pic.

The manifolds and Y piece are 3 years old in that pic

[motul1974]

phazed said:

As much as like the CF, im leaning towards you're Phazed, but in a gloss black cermaic coat.
I even had a set of brand new CF's last year to go on, but the project went on the long finger and another guy needed them before me.