Ok THIS POST promted me to ask this...for a 9A (assumed tuned, it will be at some point!) How does peoples exhaust diam change through their systems?, and what's a suggested 'best' set-up for performance (ignoring noise/looks/form). My Ashley 4-1 16V conversion manifold finishes as 2.25" (approx 57mm). 2.25" to centre box...then 2.5" (approx) from rear of centre box to rear box, then of course an outlet (I assume form is irrelavent here). Considering a few options, (for the mo i'll stick with what i've got)...what do people think: a. Full system (ie all) 2.25" b. Full system 2.5", (with adaptor to 2.25 at manifold end) ...and ditch centre box for a pipe section? Or not? People have mentioned they have 2.5" systems...from where? manifold goes down to this? Or adaptor to bring diam up after manifold?? Theres lot sof you mk2 16v boyos, how does your exhaust set-up work? Do jetex 2.5" systems fit to std manfolds or is everyone using adaptors etc! All seems pointless going for a 2.5" when systems are already restricted by the manifold, but there must be a reason why people have done! To me it would seem logical to go for 2.25" all the way through, changes in diam just disrupting flow of gases, creating velocity drops in whatever random places people put them, hardly a 'tuned' method!
Seriously, no replies at all? Everyone I asked at ACE Cafe meet didnt really have an opinion on what was best to go for, seems people just go for what sounds good, and brand/quality, lots of sound theory on what affects performance but no real conclusions on what works best.... Edited by: ManicGTI
I have a full 2.25" supersprint setup and am content witht the performance from it. i like how it looks and seems to perform well. If I had the choice again, I think I would go for the Jetex Rallye system which is a 2.5" system again with one silencer. It is bloody loud on full load but not bad on cruising.
Without wanting to sound flippant, I just don't think many people really think very much about what exhaust setup is best. If I recall correctly there's some info on exhaust tuning in Alexander G Bell's 4 Stroke Performance Tuning.
yea, people just go with whats already available. I went with supersprint because they apparently test each system to give gains in power and torque. I know my car hasn't suffered from any loss since the installation but i guess there is more in it yet.
Cheers guys Don't get me wrong, wasn't suggesting I would get any silly power increases, just interested on how set-ups work, whether or not its worth getting a straight through centre section etc. I'll stick with my 2.25 into 2.5 for the moment, might experiment with a straight through 2.5" centre section if its cheap enough. Dave
The 2.5" Jetex system gives an increase over standard definatley. My Milltek 4 branch will be fitted this weekend, forget what diameter it is, but will check. I'll update on my opinions and Rolling Road increases after that.
i have a steel jetex 2.5 inch system, joined to an ashley 4 branch. sounds loveley. havent had chance to get the car RR yet, but will do soon. only problem with the 2.5 inch system is its a bit of a squeeze on a mk1 fitting it over the beam, and there isnt much clearance on the front ARB either. it knocks from time to time but i can live with it.
IV mk1 16v runs the same Jetex rally system/Ashley on his mk1 with ABF 2litre 16v. That car goes like hot snot. Jetex 2.5" stainless system on my mk2 with stock front pipe, you get an adaptor to sleeve from 2.25 to 2.5 " with it.. Edited by: GVK
ahh, excellent. sounds like the option to go for. Have had my ickle custom front section sorted out now, havent had a chane to look at it yet but seems to work, 2.25 S/S with a powerflow 2.25" bore flexijoint, going from the ashely 2.25" manifold to the existing 2.25" system, hopefully where any off the shelf system would fit as well. ,
I'd say it is Sam, my engine ran plenty well enough on the old 2.25" Scorpion system, it just fell apart inside thats why I changed it.
Nice one gary, think i'l keep my 2.25" system for now My 16v rocco manifold and downpipe arrived today from usa Just need to find best way of mating downpipe to my system as they both been hacked off for easy removal
Have had a look at the Remus system........excellent quality and design and is the same as Sebring. F1 use Remus that's why I plumped for Remus.For the MK2 valver they do a 2.5 inch diameter system. Elite wheels and tyres in Rainham Essex is the sole distributer and is cheapest by far. Nice and quiet on cruise mode too I had one on my 2 litre valver which worked very well mated to a Magnex manifold. The car was giving just over 202bhp and 162lbs of torque with everything else. I swear by Remus it used to provide very good result on my valver with just a flowed head and manifold when the car was a 1.8 16V. I found the Jetex good but quite a bit louder on everyday use compared to the Remus system.I tried Jetex on my old valver Ian
