Originally Posted by XR8_Ute
Thanks guys. Yeah i've done alot of exhaust research here and people seem to be split as to what's best. I gather the general consencus is: * Duals sound better but less gains * Single drones, but best gains. This sound right? Exhaust will definately come first, just seeing what else before i got it re-tuned with aftermarket chip.
I always wonder too, with the availability of these simple bolt on mods like the RR's, why didn't Ford put them on in the first place and advertise the car as 190Kw or whatever...... if it's so easy? I've never doen any internal motor work, would it be a job for the experts, albeit i'm very quick to learn. Does the motor require re-tuning after install?
There are too many variables in exhaust design – including interaction with other modifications to make an all-encompassing statement like “singles drone but go, twin sound good but don’t go”. However I would expect that twins would be less susceptible to drone (read more forgiving of bad designs). With regard to power output, you have to consider this as a function of frequency (engine speed). Windsors especially rely on back pressure for low down oomph. With my stock headers, I could light up the rear wheels from just idle. Now with the pacemakers I can hardly get them to chirp from idle (loss of back pressure = loss of low rev torque) but my Ľ mile times were reduces because at higher reves, the engine was breathing much better so you need to determine what you what from your system. Personally I love the sound of an 8 and I believe that the 8’s are typically pretty strong down low anyway so I’m gong to investigate a twin system for those reasons ( I’ll be selling my current 2 ˝ “ mandrel bent cat back at that stage if you’re interested
The research I was referring to was also with regards to muffler brands. It seems that Magnaflow are the ducks-nuts but dear and not as common in Australia. I’m leaning towards Lukey straight throughs for my new system as I’ve got 1 of them now and it sounds good; the reviews I’ve read speak highly of them too so that’s my current state of thinking.
With regards to the “why didn’t ford put on the RR’s” well then who would buy the more expensive models? Usually you have an engine base and you detune it the further down the model line you go as an incentive for buyers to option up their purchase. Also it leaves scope for subsequent series runs to up the ante. Who would want to upgrade to a series II or whatever if there’s no power increase
You can reset the computer if you like after the RR install. I didn’t and everything was fine. Read my post further up, one of those links was to a thread in which I detailed my RR install. It is easy to do even if you’ve got no experience. Read the thread, there are pics
Originally Posted by XR8_Ute
Also: Just got this email reply. Comments.........?
Buy the next issue of Performance Ford Magazine, we have done testing on a AU XR-8 with bolt on mods like heads, cam, manifold and 1.72 YT rockers. We picked up 6kw at the wheels by changing the rockers only. It is a straight bolt on rocker swap, the only complication is they may foul on the factory rocker covers. We got around that by using thicker rocker cover gaskets, this raised them up just enough to clear the rockers. We have a set of rockers on the shelf for $562 inc gst, thick gaskets are $28.
I hope this info helps
Well my comment would be … buy the magazine! Yes you certainly do need to watch rocker cover clearance, especially when you look at the roller rocker geometry compared to the very low profile standard 1.6:1 ratio rockers!