mystery machine Posted March 14, 2011 Posted March 14, 2011 (edited) Hi folks, I plan to replace my exhaust from the turbo back, prior to ECU remapping. I've more-or-less decided on a Cobrasport decat downpipe and resonated centre section, just not too sure what to do about a back box... Actually pretty happy with the quiet standard STI box that's on the car at the mo', but it's looking a bit rusty around the edges, so this would seem like a good time to replace it with a nice shiny stainless steel item I've ruled out the Cobrasport BB after listening to the clips on their site – too loud and ratty for me. Had a listen to some YouTube vids of other backboxes and actually the Prodrive is probably about as loud as I'd want to go! Can anyone suggest where I might source a Prodrive backbox, or recommend an (as quiet) alternative? Many thanks again Edited March 15, 2011 by Mystery Machine
mystery machine Posted March 14, 2011 Author Posted March 14, 2011 Also, might sound like a daft question, but as I know f-all about exhaust fittings... Do all the sections of the exhaust have to have the same bore size? E.g. can a 3" bore centre section be bolted straight onto a 2.5" bore back box? Thanks.
Spaceman Posted March 14, 2011 Posted March 14, 2011 a 2.5 bb will bolt on to a 3 inch centre but its really pointless as it will just be a choke point bud i felt that the prodrive box was really restictive when i took a afterburner vortex off mine. if i was you bud id take a look at hayward and scott or tsl H&S do a prodrive style BB in 3" pipe im sure and tsl do a similar one in 3" sure its called Group n bb iv had the group n tsl jobbie and it was really nice looking and not loud at all just a nice burble with a bit of a bark flat out crusing around it was same as prodrive noise level wise.
05WRX Posted March 14, 2011 Posted March 14, 2011 The racebox from scoobyworld is a good alternative to the prodrive backbox.
Spaceman Posted March 14, 2011 Posted March 14, 2011 group n tsl job might only be in 2.5 inch bore http://www.tsl-motorsport.co.uk/newsite/products.php?nav=300000§ion=300008&detail=35 yea had and look and it must have been the H&S rear box i had this one http://www.haywardandscott.com/subaru/impreza-new-age/subaru-new-age-3-backbox.html i got mine off ebay in as new condition for bout £80 keep an eye on there bud or in scoobynet for sale general.
mystery machine Posted March 14, 2011 Author Posted March 14, 2011 (edited) a 2.5 bb will bolt on to a 3 inch centre but its really pointless as it will just be a choke point bud i felt that the prodrive box was really restictive when i took a afterburner vortex off mine. if i was you bud id take a look at hayward and scott or tsl H&S do a prodrive style BB in 3" pipe im sure and tsl do a similar one in 3" sure its called Group n bb iv had the group n tsl jobbie and it was really nice looking and not loud at all just a nice burble with a bit of a bark flat out crusing around it was same as prodrive noise level wise. Cheers mate. I thought that the 2.5" bore only became restrictive when pushing above 350bhp (or 400bhp according to some sources)? I'm shooting for 320-340ish. TBH, I was leaning towards 2.5" all the way through as that's supposed to produce less cabin noise. However, I had considered that I might go for 3" on the downpipe and centre section, and wondered if I could bolt my standard STI BB onto that until I find a suitable replacement BB (hence the question about mis-matched bore sizes). Edited March 14, 2011 by Mystery Machine
mystery machine Posted March 14, 2011 Author Posted March 14, 2011 yea had and look and it must have been the H&S rear box i had this one http://www.haywardandscott.com/subaru/impreza-new-age/subaru-new-age-3-backbox.html i got mine off ebay in as new condition for bout £80 keep an eye on there bud or in scoobynet for sale general. The H&S looks nice, very like the standard tailpipe, which I like. How did it sound compared to the Prodrive then? 05WRX – thanks for the clips. TBH, it's hard to tell how those back boxes would sound against the engine, road noise, etc... actually the most useful clips I find are those where the car is filmed driving past the camera. Cheers folks
Spaceman Posted March 14, 2011 Posted March 14, 2011 it was similar to prodrive not so much louder just a bit of a deeper tone was nicer you could hear it better but it wasn`t intrusive at all.
mystery machine Posted March 14, 2011 Author Posted March 14, 2011 (edited) 05WRX thanks for the clips. TBH, it's hard to tell how those back boxes would sound against the engine, road noise, etc... actually the most useful clips I find are those where the car is filmed driving past the camera. I did mean to comment that the Racebox does sound quite nice in those clips, just hard to judge the volume Thanks again Edited March 14, 2011 by Mystery Machine
mystery machine Posted March 14, 2011 Author Posted March 14, 2011 Looks like the Cobrasport sports cat downpipe is 3" bore, and I notice a lot of the 'cat back' systems are 2.5" or 2.75", so I might just have to mis-match bore sizes...
mystery machine Posted March 14, 2011 Author Posted March 14, 2011 (edited) Facetube clip of a 2.5 hatch with H&S turbo back system: Sounds nice, but too loud for me I think... don't want to attract too much attention to myself when I'm hoofing it around the back roads P.S. Guess the driver in that clip must've been pretty confident that no-one was coming other way as he appeared around that blind bend halfway onto the wrong side of the road... Edited March 14, 2011 by Mystery Machine
scooby222 Posted March 14, 2011 Posted March 14, 2011 how about going to c and c, meercat or a powerflow type place and just get a system made up to your own requirements? wouldnt imagine itd be a good idea to go from 3" pipework to 2.5" tailpipe - other way round would be fine also have a look for an sti genome backbox, very nice and quite subtle - personally my prodrive backbox lasted a whole month - waaaay too quiet,release the flat four!
mystery machine Posted March 14, 2011 Author Posted March 14, 2011 (edited) Cheers for the input, Dave. I'd love to roll into the Meercat one-stop-shop, but TBH I just can't face the thought of taking the Scoob through to the other side of Glasgow... what are the chances of getting down there these days without driving through some huge pothole? Where is C and C then? STI Genome... I'll need to check that one out, cheers You didn't keep your Prodrive box, by any chance? Edited March 14, 2011 by Mystery Machine
Spaceman Posted March 14, 2011 Posted March 14, 2011 go see the guys at stainless creations down bankside they are really good and have done a good few scoobs They take there time and care about the job they do they can build the full lot with sport cat too, any tail pipe and noise you want def worth talking too.
mystery machine Posted March 14, 2011 Author Posted March 14, 2011 (edited) Cheers, SM didn't know they existed! Just had a Brands Hatch at their site think I'll give them a bell tomorrow Edited March 14, 2011 by Mystery Machine
mystery machine Posted March 14, 2011 Author Posted March 14, 2011 (edited) Hey, looks like they did this Scoob that I posted about in the 'was it you' forum (Mr 'Bigot'): I thought it was a Spec D when I passed it, but of course it's a WRX. Edited March 14, 2011 by Mystery Machine
mystery machine Posted March 14, 2011 Author Posted March 14, 2011 (edited) Crickey, the more I see, the more I like! http://www.stainless-creations.co.uk/shows.htm Edited March 14, 2011 by Mystery Machine
scooby222 Posted March 14, 2011 Posted March 14, 2011 sorry mate prodrive exhaust got sold ages ago! that looks like a good bet, didnt know about them either Greig - hows the hawk going?
mystery machine Posted March 14, 2011 Author Posted March 14, 2011 Greig - hows the hawk going? I believe it's now a 330d Touring
bobbyc Posted March 14, 2011 Posted March 14, 2011 (edited) Iain & myself carried out exactly the same mods to the GB's with the exception of the exhausts, Iain went for a 3" full decat I went for 2.5" sportscat, difference when mapping 3bhp not worth talking about, torque was 390+ apart from the prodrive sportscat Stainless Creations in Falkirk did the rest, they'll do you any style of tailpipe you want they use cobra back boxes Personally I wouldn't bother with the hassle of the decat route unless you think the slight gain in bhp is going to benefit you Edited March 14, 2011 by bobbyc
mystery machine Posted March 14, 2011 Author Posted March 14, 2011 Cheers for the info Bobby Do Stainless Creations not do sports cats then?
Spaceman Posted March 14, 2011 Posted March 14, 2011 (edited) sorry mate prodrive exhaust got sold ages ago! that looks like a good bet, didnt know about them either Greig - hows the hawk going? yup a 330d touring now bout to get it mapped and start playing wonder what it will be like at knockers. the hawk is now owned by big fud off Snet and is being run in with a fully forged engine with nice cosworth parts lol think its running a solid 400/400 or more and will be competing at scooby sprint when its not lapping the Ring. and yup they def do sport cats at stainless creations Edited March 14, 2011 by Spaceman
bobbyc Posted March 14, 2011 Posted March 14, 2011 Cheers for the info Bobby Do Stainless Creations not do sports cats then? Yep they do I just happened to have a prodrive sportscat in my junkyard of scooby spares lol
mystery machine Posted March 15, 2011 Author Posted March 15, 2011 (edited) Greig and Bobby: Just wanted to thank you for putting me onto Stainless Creations – spoke to Graydon today. They seem very willing to accommodate and reasonably-priced too. Been quoted £640 for a 2.5" bore two-part system – sports cat pipe up-front and a dual-silencer pipe behind that. Almost certainly going to go for that. Thanks again! Edited March 15, 2011 by Mystery Machine
Spaceman Posted March 15, 2011 Posted March 15, 2011 good stuff just make sure the are making the downpipe open mouth sure they wil be though there pretty clued up.
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