Every little helps :)
Discussion
I had an exhaust blow that occurred recently so took the opportunity to fit a set of lovely ACT big bore manifolds.
They fitted very nicely and I took Tim's advice to clean them with a solvent before firing up. I did and they turned a nice gold colour.
Sound wise, they sound more urgent with the soft RV8 burble suppressed and a very likeable off beat sound under 2K revs. Strangely, the under bonnet sound seems less!
On the road the engine felt crisp and I hit the rev limiter, (6K) a few times which I have never done before. I can only assume that it has made the engine a little more free reving at the top end.
Off to Surrey Rolling Road this morning. I met Barrie there and I held my breath while Charlie ran it up on the rollers.
When the car was at SRR last year in the same state of tune but with a fully decatted standard set of manifolds and Y piece it ran the lower lines on the graph, (388bhp).
This time, the increased feeling of urgency on the road equated to a power hike in BHP, (404.4 bhp) and torque although moving the torque up the range a little.
It seems to peak out at 6K at the rev limiter so I may have that raised by 500 rpm and see what happens.
I am extremely pleased at the result and give Tim a big thumbs up for an excellent product that not only looks great but does the business!
BTW, SRRs figures are practically identical to Joolz's who recently fitted the Emerald system that it is running.
They fitted very nicely and I took Tim's advice to clean them with a solvent before firing up. I did and they turned a nice gold colour.
Sound wise, they sound more urgent with the soft RV8 burble suppressed and a very likeable off beat sound under 2K revs. Strangely, the under bonnet sound seems less!
On the road the engine felt crisp and I hit the rev limiter, (6K) a few times which I have never done before. I can only assume that it has made the engine a little more free reving at the top end.
Off to Surrey Rolling Road this morning. I met Barrie there and I held my breath while Charlie ran it up on the rollers.
When the car was at SRR last year in the same state of tune but with a fully decatted standard set of manifolds and Y piece it ran the lower lines on the graph, (388bhp).
This time, the increased feeling of urgency on the road equated to a power hike in BHP, (404.4 bhp) and torque although moving the torque up the range a little.
It seems to peak out at 6K at the rev limiter so I may have that raised by 500 rpm and see what happens.
I am extremely pleased at the result and give Tim a big thumbs up for an excellent product that not only looks great but does the business!
BTW, SRRs figures are practically identical to Joolz's who recently fitted the Emerald system that it is running.
and those big numbers 
Clive said his std replacement manifolds were just that, and not there for a performance upgrade and it's his BIG one that could give 20-25bhp, just seems strange that his std one offer no improvements?....bettrr looking primaries, from what my Google mechanic skills can see!
I need decide what I'm gunna get very soon.
I need decide what I'm gunna get very soon.
You should take into account Peters is already very powerful so the gains might be a bit less on a lower tuned engine but still this is a fantastic figure
Congratulations Peter. I’m not sure now who mentioned this before but if the exhaust tubes don’t line up well with ports your going to loose hp and this just shows having no restriction is the way to go.
There can’t be to many road going n/a Chims that have ever had these sort of numbers on I’d imagine.
Something of a mile stone I’d say.
So porting is the way to go then
Congratulations Peter. I’m not sure now who mentioned this before but if the exhaust tubes don’t line up well with ports your going to loose hp and this just shows having no restriction is the way to go.
There can’t be to many road going n/a Chims that have ever had these sort of numbers on I’d imagine.
Something of a mile stone I’d say.
So porting is the way to go then
Edited by Classic Chim on Saturday 7th April 20:31
probably about as damp as the last time it was tested I’d fully imagine 
SILICONEKID 345HP 12.03 said:
Clive did test the ACT setup which you have unless larger bore against standard manifolds and his smooth bore Y piece .
The results did not give the the setup any more power .
Are these ACT manifolds a larger bore than any other act manifolds .
Was it very damp at the rolling road session ?
The results did not give the the setup any more power .
Are these ACT manifolds a larger bore than any other act manifolds .
Was it very damp at the rolling road session ?
makes the outlay worthwhile 
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