matth76

Does anyone know the outlet diameter of the end of the exhaust manifold which connects to the catalytic converters - is it 2.36" same as rest of standard exhaust system or is it slightly less like 2.25"? I'm possibly getting some aftermarket cats or decats and want to ideally get the right inlet diam to match up to the outlet diameter of the exhaust manifold so there's no restriction. I believe the Nismo Y-pipe inlet is 2.5" (which then goes to a 3" outlet) - can anyone confirm? Some decats have different inlet diameters of 2.25" going into a 2.5" outlet. This would be fine for connecting to my Nismo Y-pipe (if indeed it does have a 2.5" inlet). Just wondered what the outlet was of the exhaust manifold - anyone? Thanks for any info.

Was that a Motordyne spacer or another brand? Was the before and after dyno done at the same place same day?

I have heard the Motordyne 1/2" plenum spacer will add more of a "growl" to your 350z but is the same true of the thinner 5/16" plenum spacer but just to a slightly lesser extent, or is the extra noise barely noticable? Done a search but cannot find any info about this. Thanks for any help and info.

Thanks for your reply. I thought the extra sound would only come from fitting a thicker 1/2" MD spacer and that there was no noticable sound increase with a 5/16" spacer. Is this not the case? I definitely want my car to be louder I'd kind of discounted the 5/16" spacer due to the fact it wouldn't really add any sound - unless I got the thicker 1/2".

Thanks for all your replies and help guys. Appreciate it. Yes Mark you gave me the quotes for Berk decats and XYZ pipe thanks for your help with that. Looks like a very nice bit of kit and with proven gains. Just a pain that I have shelled out on a Nismo system only a couple of weeks ago. Just can't quite stretch to the XYZ pipe because I was wanting to get the Uprev too. What ever happens I am getting the Uprev at the end of my mods so have to keep that in my budget. Currently my car has the cat back Nismo system with Nismo Y-pipe no other mods. My options are: - keep Nismo Y-pipe, fit resonated decats - keep Nismo Y-pipe, fit high flow cats - get rid off Nismo Y-pipe, fit XYZ pipe with race cat, and replace two stock cats with Berk decats. - keep Nismo Y-pipe, keep stock cats, just fit MD spacer I'm trying to keep costs down as I have spent quite a bit already on the Nismo, so will either get MD spacer or decats/hfc, not both. I can't find anyone who has proven dyno results of an MD spacer (other than MD themselves) but do know decats/hfc give proven gains plus they give a bit more sound which I definitely want. In hindsight I wish I'd gotten the MD dual ti full system which includes XYZ pipe for about £1200 however at the time I didn't know Abbey or in fact anyone in the UK had them in stock. So I contacted MD direct and I was quoted nearly £500 shipping so instead ended up snapping up this second hand Nismo which I have now. Unfortunately I had to bin my stock exhaust as it was badly corroded and had to be cut to get off (only four years old - not good Nissan!) so someone is likely to get a good bargain when they buy my car in the future because it will come with a Nismo! Anyway back to my mods - I think realistically out of my options above I think resonated decats would be the best compromise - better power and flow than hfc as people have mentioned, minimal rasp and low cost and nice growl which I am after, just don't want rasp and don't want to lose low down torque (but this is questionable). And then Uprev to get the most power. What do you think Mark? 3Fiddyz, my car was putting out between 230 to 240 hp at the wheels at Gary's when totally stock with just over 240 lbs/ft torque at the wheels too. If I remember rightly my car was running a bit rich which I believe can be sorted out with a map and will result in good power.

Thanks. Yes did think about that too. I'm very indecisive I admit so have not yet discounted high flow cats or decats so may yet fit either. If I do get any hfc I may get the Ultimate Racing ceramic ones which Adam recommended. They have a support bracket and the flanges fit perfectly with a Nismo so should tick all the boxes. To have an MD spacer supplied and fitted is going to cost around the £300 mark total. I should be able to source some Ultimate Racing cats for around the £430 mark after import taxes and delivery to UK (should have an accurate cost tomorrow) - so (aside from my "concerns" earlier) really just down to which would yeild most power and be more worth it because financially I am not going to do both - it is either spacer OR hfc and then finally Uprev and my car is "complete". I'm erring towards the hfc as opposed to spacer as being more worth it in terms of power and sound. I do really want hfc to complement my Nismo and get more sound. Watch this space as it were.

Thanks for your reply. Yes I agree. I am going to leave my standard cats on just to be safe. I don't mind missing out on the 5 extra bhp top end you'd get with decats. It's strange as to why the Nismo Y-pipe causes so many issues with hfc. Some say it is the lack of flex but strange it doesn't seem to affect other brands as much.

Thanks for your replies guys. I believe Adam mentioned the Ultimate Racing ceramic high flow cats were the best when suited with the Nismo Y-pipe. However no-one in UK offers Ultimate Racing cats and I've worked out to import from the US it will work out at around £450-500. I'm prepared to pay that as I know that is the going rate for hfc but just a bit of a worry if they are going to crack a year or two down the line especially after spending a lot to get them. If they had a certain mileage or two year warranty I would be less worried but I don't think they do. I don't think many people seem to run the Ultimate Racing cats (no-one on the my350z.com appears to have them) so hard to tell how good they are nor does anyone know how they sound with a Nismo. Berks which are very popular are supposed to be very good quality but when connected to the Nismo Y-pipe they are very prone to cracking so not good in that respect. My350z.com has quite a lot of cases of guys in the States that have had two sets of Berks crack on them with a Nismo cat back, some in just over a year So I ended up thinking I should go for resonated test pipes instead as if they crack it is less of an outlay to risk compared to hfc. But the rasp and loss of low down power has given me doubts about getting them. I may yet get some resonated test pipes as you can get some Japspeed ones for £130 inc shipping and vat but don't know of any people running them with a Nismo or of their quality. If anyone has a Nismo cat back (inc Nismo Y-pipe) and is running resonated test pipes and get virtually no rasp and no noticable loss in low down torque, and have had no problems in over a year of running them please let me know and if possible post a very quick sound clip!

Have you had your car dyno'd? With or without the new mods? Yes, when it was totally stock, why? However I have had it dynoed at a different place to Abbey so expect different power outputs from dyno to dyno but will not have a baseline figure at Abbey to compare to which is a shame (I'll be able to see a before and after having the Uprev but not my actual mods). I will however be going back to my original dyno place GT Art (where I have my base numbers, ie when totally stock) after the Uprev and mods but even then it is a few months after my baseline dyno was done but will give me a good idea how well my car has done since it was totally stock. However I am only really interested to know the average gains achieved are with the above kinds of mods so I can know what to expect. As long as my car feels good on the road that is what matters to me which the uprev is supposed to be good for .."nice" numbers are a bonus (but I'm not expecting much of an increase top end, maybe 6 to 8 bhp top end at most with plenum spacer and exhaust). My car definitely feels stronger since I added my new exhaust although I suspect my ecu will be cancelling out any actual gains until I have the uprev remap. I was contemplating adding high flow cats or decats but have been reading more negatives about both with the Nismo Y-pipe - hfc can crack, and with decats they can also crack or worse, you lose low down torque which I definitely don't want. Is a pain as I love the sound of the Berk high flow cats with the Nismo but can't risk them cracking 12 months down the line which appears very common over in the States for those running any kind of hfc with a Nismo y-pipe. So going to keep it simple for now.

Hi Mark, have you any results for the Uprev tuning for a 276bhp 350z which has stock cats and stock air box but has just exhaust, Y-pipe and MD plenum spacer? I'm more interested to know the gains throughout the rev range as I know this is where the gains are achieved most. Top end gains are a bonus.

Sounds very similar to my old car. My rear wheel arch was all caved in. However the person had actually left their number on my windscreen which I thought was quite rare but nice. He turned out to be a neighbour of mine a few doors up who backed out of his drive and clipped my car. Could well be one of your neighbours. Now I never park opposite his drive! But he was thoughtful leaving his number and really friendly when I rang him and admitted total fault. Took about five weeks to get car finally fixed but that was all down to Elephant Insurance who wanted to get their own estimate first but took about two weeks just to pick the car up! Eventually got my mate, who is a local bodyshop worker to fix it for a fraction of their estimate - as their estimate would have meant writing my car off due to their estimate coming in at around over £2k. But my mate got it all done for £600 and did a great job. That was all on my old mark 3 golf vr6 (1997 2.8 litre) which wasn't worth much hence they wanted to write it off but it probably had about an extra £4k worth of work on it, but they don't look at this of course. Hope it all works out well and keep ringing them up if they take too long to deal with it. Elephant, which are the same as Admiral were horrendous.

I would assume low 80's dB but just a guess based on the fact that a Nismo is around high 80's and my Nismo is definitely a lot louder than stock when going over 2500 revs (but almost stock below this).

Here's a question - does running decat/test pipes invalidate your car insurance even if they have been informed you are running a non-standard exhaust?

Has the XYZ pipe proven successful?

Most probably. Its just as it joins before the y pipe. as usually its manifold - cats - Y pipe but with the xyz it will be manifold - xyz - cat/decat. Their marketing says the further back the Y is the better the power gains. You mention with the XYZ it would be in the order "exhaust manifold - connected to XYZ - then cat/decat". So does the XYZ pipe replace the two stock cats?

Hi Mark Please can you tell me your approx fitting price for you to fit the 5/16" MD plenum spacer (priced at £143 in your price list) and would you be able to fit me in on a Sat morn? Thanks for your help.

Anyone know of any?

I'm exactly the same - we went for a drive this arvo and she kept looking over at the open window lol

All sound very nice

Nice one. Looking good. I just got mine fitted yesterday. I bought mine second hand from Zmanalex too, last weekend. It sounds almost stock at idle and low revs but floor it and open the windows and you can really hear the difference. How's yours sounding?

Cheers guys I'm definitely liking it so far!

Hi guys Yesterday I got my second hand Nismo exhaust fitted by GT Art just down my road who did a great job fitting it and my old exhaust was a complete nightmare to get off. I got the exhaust last week courtesy of Zmanalex and Colin (Ebized). It was in fact from Colin's old 350z. Thank you both for your help. By the way seeing Colin's new 370z in person it is absolutely stunning My old stock exhaust had a blow in it near the backbox and was quite loud so I knew fitting the Nismo would actually make my car a bit quieter, similar to stock, and I was right but only at idle and low revs. However when you get the revs over 2500 there is now a nice howl that gets steadily louder the faster you get, which my stock exhaust (even with a blow) never had. I'm getting very addicted to pulling the windows down and blipping the throttle at every opportunity. It's like getting a new car all over lol. I have to admit it doesn't sound much like the sound clips you get on youtube - but then again I haven't stood at the back when it was revved (which is how most clips are done). I have only really experienced it sitting/driving in the car. I will need to get my gf to rev it for me when I'm standing at the rear or get her to do a drive by. I am tempted to get some high flow cats to really get the noise out. Just not sure which yet. Ultimate Racing ceramic ones look pretty good and are supposed to work well with the Nismo Y-pipe flanges. Here are some pics (taken with phone): The pic above show up all the dirt! Roads were full of puddles yesterday! My car probably needs a clean! Oh, and the car revs harder now and there is definitely an improvement in acceleration. With a remap should see some good improvement on the dyno.

Shell is notoriously expensive. Tesco 99 down my road are around 114p/l, still very expensive and nothing in the news about this second very big price hike - the first was very publicised and it then went back down to under 100p/l but no news on how it has somehow crept back up to where it was before! Anyway one thing to bear in mind it is an 80 litre tank, very large and will do around 420-430 miles per tank if driven normally which is pretty good for a sub 6 sec car. I average 32 mpg. Personally I would not go ahead with an LPG conversion. Will make it very unsaleable in my opinion. As said above the 350z is not purchased to be economical - an LPG 350z does not make sense, a bit like the 4x4 Beemers which cannot go off road!

Clarkson may have said he didn't like it, yet in that same year (think it was 2004) Top Gear actually awarded the 350z as the best coupe - so sounds like Top Gear actually overruled his opinion. Fifth gear (Tiff Needel and co) also awarded it their best coupe (for more than one year if I remember). Wouldn't worry too much about what he thinks - he is used to driving perfect cars that cost well over 100k. Don't get me wrong I really like watching him and without him Top Gear would not be the same but one of the things we have always known is that is incredibly critical. From what I remember the main thing he wasn't keen on with the 350z was it was tiring to drive round town at slower speeds which to be honest I also agree with - the clutch is incredibly clunky, very jerky gear changes in 1 and 2 and very plasticy interior. However it isn't a 60k Porsche but the Nissan engineers clearly focused on the engine as opposed to interior which is fine by me.

Thanks for the info. Definitely interested in getting the Uprev at some point.