Guest jjohart Posted December 9, 2003 Share Posted December 9, 2003 Hi, my 280ZXT is almost finished with an intercooler and 3 inch exhaust system. The one thing the installer caught me at the end about-without time to do anything-was that "he didn't have the right size flange to fit the turbo"...which I assumed meant the downpipe that everybody on this site and elsewhere trashed on this site (OEM dual 45 bends?). Well, I just got a look at the unit and the work done, and the installer basically said he didn't think replacing that part would make any substantial difference in power, that most of the restrictions were down the line in the exhaust sizing shrinking to like 2 inches! He commented that the output size of the downpipe was very close to the size of the connector at the turbo end, and said the only thing that a straight(er) pipe might do that would make a difference would be on track times. Since I don't plan on racing, do I need to make a fuss, and if so, who's selling the straightened downpipe, and do I need to go back to this installer or could I go anywhere to do that final piece? I don't know if it's worth it...opinions appreciated! John Quote Link to comment Share on other sites More sharing options...
Guest Cusp Posted December 9, 2003 Share Posted December 9, 2003 I've been waiting for someone to say this. There is minimal gains to be had by making a custom downpipe if one cannot increase the piping diameter. Since us T3 guys are stuck with 2.5" output flanges, the majority of HP freed up will be in the exhaust system, not DP. Quote Link to comment Share on other sites More sharing options...
Guest jjohart Posted December 9, 2003 Share Posted December 9, 2003 (to reply above): THANK GOD! Previous to the reply, I felt trapped, stuck, whatever, since having read the turbo guide in our turbo/supercharged "guide" 2 page entry (with all respects to guru, master who wrote it...hint, is there any chance Christmas cheer might allow mere Z mortals like I-new members, et al-a list of what the various Z grades of respondent members are, e.g guru/master/Jedi, etc?!!?)....it seems like the discussion completely trashed the down pipe as, near accurate quote, " the single worst piece of Nissan engineering...dual bends", etc. Well, I took a good look at that pipe today (acknowledging I was never really sure where it was until I did the 3" exhaust!), expecting the equivalent of the curvy porcelain tube of a toilet's lower half (below the bowl!) based on that description...what I found wasn't anywhere near as cross-eyed Mary as the master/Jedi/Guru etc (I forget the name) had indicated. In a perfect world of money trees this holiday, let's be thankful for what we've got...the early Z's are the best reason I can think of to avoid airbags, anti-lock brakes (and yes, snow!), for the safety that comes with a car so ahead of its time. Strengths and weaknesses abound, as in any car, but I had an 83 Supra (itself a ponderous pony car pretender), and 21 years later, my Z outstyles, outruns and outclasses even cars by competitors of that era...OEM DOWN PIPE or not. Just to snipe a wee bit, I have noticed that folks posting custom job stainless steer "straight pipes" for $300 have since dropped their site and e mail links, so beware custom exhaust "package" dealers (sometimes calling their runs a "group buy")..sounds to me like take the money and run, operating on the assumption that you can get a profound amount of money in a short time by convincing people, even Z owners, that if they change their exhausts, they'll get even more if they change their downpipe (akin to a dentist telling you if you're going to replace a tooth, why not change the gums as well?) uh...major off-topic, sorry! Just Z thankful for what we've got! 3 inches is enough (and no coffee can mufflers/down pipe pushers need apply!). I'm hybrid'ed up enough, just worried about boost addiction once my Z hits the road again!! John-83 280ZXT 5spd 2 + 2, NPR I/C, 3 inch exhaust, DSM blow off valve, mod.pop off valve, Greddy Profec B Boost control, Bosch H.P pump, questioning CarTec/Bell/Corky progressive fuel management's worth (not on car, offers considered!). Quote Link to comment Share on other sites More sharing options...
jeffp Posted December 28, 2003 Share Posted December 28, 2003 I have been working on a custom 3" downpipe it feels like forever. I was able to get 15 guys that wanted it, and the 2 1/2" flange to go with it. So NOT all of us are doing the "group buy thing" just to steal everyones money. Look under my posts and see how long it has taken to get this thing going, and not becuse of me, but getting everyone to get their money in and answer all of the questions then work with the bender, the box builder, buy the cats amd mufflers, it's just been a pain in the butt to say the least. I still haven't cashed everyones money orders yet and have invested 950.00 of my own money on cats and mufflers. So I hope that gives you some hope for the froup buy thing as I am all over it, well as fast as I can be. Quote Link to comment Share on other sites More sharing options...
Drax240z Posted December 28, 2003 Share Posted December 28, 2003 If you take a look at the stock downpipe and exhaust combo, you'll see the reason for my description in the turbo FAQ. The top bend is a restricted 90* bend right out of the turbo, but that is not the worst part. The bottom bend (which is often changed with an aftermarket exhaust) is a crush-bent, wrinkle-walled piece of 2.5" pipe. (often hidden by heat shielding) This bottom bend is by far the worst part of the system, but I personally wouldn't fix it without redoing the whole system right up to the turbo. The gains from the mandrel bent 2 x 45* setups out there when compared to mandrel bent 2 x 90* bends is probably slim. However, the stock cast piece is not even close to flowing like a 2.5" mandrel bend. Scottie-GNZ back in his L6 days reported huge gains from his 45* downpipe & 3" mandrel bent exhaust conversion... BradD is another guy that did some research on the stock downpipe, eventually opting for a 3" downpipe with a diffuser to open it up from the stock outlet size. (2-1/8" IIRC) I'd be willing to bet everything I own that there is a noticeable seat of the pants improvement from the stock downpipe/wrinkle wall bend to the mandrel bent downpipe Scottie-GNZ had made, with a 3" exhaust installed after the downpipe. But hey, what do I know? As far as questioning the integrity of those offering up group buys on this board, I think you are quite out of line. These people put in a ton of their time, research and often their own money just to organize things to help out fellow Z enthusiests. Custom parts take a lot of time, and a sizable portion of money. I for one won't buy Jeff's exhaust (because it's for a ZX, and I don't have one) but I really appreciate the work and time he's put into making a well engineered system for people. Quote Link to comment Share on other sites More sharing options...
Cody 82 ZXT Posted January 5, 2004 Share Posted January 5, 2004 I for one can tell you that just replacing the downpipe will make power for anyone looking to get the most out of their Z. If your not looking to get the most out of the car then why bother with any of it. To me it sounds like the "installer" is just lazy or doesn't know what he's talking about. I was once told the samething from a performance shop here in the local area that has had several magazine cars and a good reputation for building big power. Let's just say I don't buy or recommend them to anyone any more since they have given me bad advise on subjects such as "the factory DP is fine". I wish it was true but, it's not. Quote Link to comment Share on other sites More sharing options...
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