rogerxp Posted June 17, 2011 Share Posted June 17, 2011 Can I just throw a quick question into the mix... ...I keep picking up various nuggets of information from various threads but here's my question... What would be the result of sticking some HFCs onto my standard car (with no fancy exhaust or remap)??? Would this -: * increase bhp * improve power delivery * screw-up mpg * increase sound The point I'm most interested in is the sound issue. I've heard it does improve sound so, in my quest to bring a bit of voice back to the Z family, can I just get some HCFs and forget about the exhaust (what is the vocal difference between just an exhaust upgrade or just HFCs) Sorry, I know these issues are talked to death, but I'm still struggling to grasp it. Just wondering what advice you guys can offer before I speak to Tarmac . Quote Link to comment Share on other sites More sharing options...
coldel Posted June 17, 2011 Share Posted June 17, 2011 Interested in this also...I am undecided about what exhaust to get at the moment (am in a 350z) but for sure there is only one real solution for MoT passing Cat replacement - it would make more sense to buy the HFC and take it from there... Quote Link to comment Share on other sites More sharing options...
The G Man Posted June 17, 2011 Share Posted June 17, 2011 I haven't heard of anyone running HFC's with a stock exhaust in a 370, but I would guess that the stock system would not allow you to get the best out of the HFC's. * increase bhp, no, highly unlikely on its own * improve power delivery, no, not with that strangled bastardised excuse of a stock exhaust. * screw-up mpg, no, hasn't on mine with the Akro/Berk combo. * increase sound, yes, probably but better with an aftermarket exhaust. These are just my feelings on it, a more technical view will most likely come along any minute Quote Link to comment Share on other sites More sharing options...
rogerxp Posted June 17, 2011 Author Share Posted June 17, 2011 So, for the price, perhaps worth a stab??? I don't even understand what the hell the HFCs do (or where they go for that matter ) but am just desperate for a bit more sound. BUT, I'm after what the 350Z delivers as opposed to some chavvy-arsed charriot . Quote Link to comment Share on other sites More sharing options...
The G Man Posted June 17, 2011 Share Posted June 17, 2011 I would combo them with a less restrictive aftermarket exhaust, this depends on your budget. HFC's are a less restrictive catalytic converter, will allow passing of an MOT. The Garage in Motherwell where mine were fitted, offered an indepth explanation on the differences. The HFC's are from the manifold to either your Y pipe or straight through exhaust, to backbox. You will get a perfectly grown up sound with most combo's, as a 370 should sound, if you can stretch the budget, then IMO, the Akro is the best on offer, there are loads on here running different combo's though, Stillen, HKS, Scorpion etc. The HFC's alone will not give you your desired effect. Quote Link to comment Share on other sites More sharing options...
philb1965 Posted June 17, 2011 Share Posted June 17, 2011 Have a search on youtube, there are a few vids for stock 370z + HFC's This sounds pretty good to me. This one is quite comprehensive. Quote Link to comment Share on other sites More sharing options...
Chris`I Posted June 17, 2011 Share Posted June 17, 2011 HFCs with standard exhaust will just give you a slightly louder, rought/raspier kind of noise. It wont really sing like one with an aftermarket exhuast and HFCs, nor will it give you any more power. In the manifold > cats > y-pipe > exhaust chain its the Y-pipe w/secondary cats that strangle the system, not the cats. Once you have removed that (with an aftermarket Y-pipe), then the next restriction is the cats, but not by much. So in terms of noise, you will get a little, but not as nice (IMO) as an aftermarket exhaust, nor will you get any extra power. However if you are looking to get an exhaust and remap later then they will be worthwhile to get them now if thats what you want Quote Link to comment Share on other sites More sharing options...
rogerxp Posted June 17, 2011 Author Share Posted June 17, 2011 So in terms of noise, you will get a little, but not as nice (IMO) as an aftermarket exhaust, nor will you get any extra power. However if you are looking to get an exhaust and remap later then they will be worthwhile to get them now if thats what you want I think this is exactly it Chris. I'm not bothered about more power (honestly ) but would like more sound however want the sound to be the right sound if you know what I mean. Pretty hard to explain. I would like a new exhaust though so, if I can get some HFCs now for the right price, I'll maybe just hold onto them (or stick them on just on the off chance they keep me happy!!!). Quote Link to comment Share on other sites More sharing options...
Chris`I Posted June 17, 2011 Share Posted June 17, 2011 You'll notice a difference in noise thats for sure, but it might not be the "right" noise. Only one way to find out Quote Link to comment Share on other sites More sharing options...
rogerxp Posted June 17, 2011 Author Share Posted June 17, 2011 I wish you guys would help me earn it quicker than you help me spend it!!! Quote Link to comment Share on other sites More sharing options...
martinmac Posted June 17, 2011 Share Posted June 17, 2011 Dont worry, I only intended changing the aerial. Quote Link to comment Share on other sites More sharing options...
rogerxp Posted June 17, 2011 Author Share Posted June 17, 2011 Ha ha, not got round to that but, as a matter of interest, what aerial gave you got??? Quote Link to comment Share on other sites More sharing options...
bakseedaa Posted June 17, 2011 Share Posted June 17, 2011 Why dont you just let it all take place naturally, If you get the HFCs first then a few months maybe weeks later you WILL get the aftermarket exhaust and then after that depending on which exhaust you buy the Y pipe. There is no point trying to fight it its called Evolution Quote Link to comment Share on other sites More sharing options...
rogerxp Posted June 17, 2011 Author Share Posted June 17, 2011 Sounds like a plan . Quote Link to comment Share on other sites More sharing options...
bubbagross Posted June 18, 2011 Share Posted June 18, 2011 HFCs with standard exhaust will just give you a slightly louder, rought/raspier kind of noise. It wont really sing like one with an aftermarket exhuast and HFCs, nor will it give you any more power. In the manifold > cats > y-pipe > exhaust chain its the Y-pipe w/secondary cats that strangle the system, not the cats. Once you have removed that (with an aftermarket Y-pipe), then the next restriction is the cats, but not by much. So in terms of noise, you will get a little, but not as nice (IMO) as an aftermarket exhaust, nor will you get any extra power. However if you are looking to get an exhaust and remap later then they will be worthwhile to get them now if thats what you want So would it be fair to say that we should consider an after Market Y pipe before even the HFC's then? Eg for those of us on a budget do the Y pipe first, then HFC's and then exhaust?? Quote Link to comment Share on other sites More sharing options...
Chris`I Posted June 18, 2011 Share Posted June 18, 2011 So would it be fair to say that we should consider an after Market Y pipe before even the HFC's then? Eg for those of us on a budget do the Y pipe first, then HFC's and then exhaust?? Kind of - speak to Mark @ Abbey about it, he will put you straight with the options. Most aftermarket exhausts come with a Y-pipe, and Y-pipes on their own plus an exhaust later is more than just getting an exhaust inc Y-pipe in the first place. Best way to do it IMO is to get an exhaust that inc Y-pipe then get HFCs later if you want them. Unless of course you get offered a set of HFCs or Y-pipe dirt cheap in which case go for them, but evenutally you'll want a "full set" of breathing mods to make the most of it all. Quote Link to comment Share on other sites More sharing options...
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