Dat73z

Thanks @Zetsaz! It's not perfect but I've learned a lot. I think I'm finally at the tail end of this project. I spent like an hour positioning the muffler and hangers. I think I'm going to tack the muffler hangers first to lock in that positioning then fit up the final tubes. I'll probably do one joint at a time and be super careful with the heat input so in case anything moves I can still do some fine tube profile adjustments. I'm planning to add 2 more hangers, one by the diff and one to brace the downpipe. Then the o2 sensor bung. Finally send the downpipe off to be inconel shielded.

A bit off topic but maybe someone searching someday may find useful. One thing that I've found really helpful on SS tube is just cranking up the post flow. I think I was hesitant to try it earlier as I was attempting to save gas but to my untrained eyes I've noticed even when I run further the quality of the final weld appearance seems to improve as well.

That is a good point. I actually pringled out one vband early on but fortunately I had a spare as I only needed one side for the turbo. I think I kept the warpage for them all to a minimum but worst case I'll get them skimmed by my local machinist. I feel like I've had to re-teach myself tig fundamentals through this project but I guess there's no better way to learn than by doing

Finally got a solid hour today and finished welding out the midpipe. It felt like a small victory after a crazy schedule this past few weeks. Tomorrow I have a few hours off so I'm hoping I can tack and start welding out the rear section. Now that I have a bit more fabrication experience, fitup is getting a bit quicker but I think I need to pay more attention to making absolutely sure everything is "white glove" clean before welding

@AydinZ71 yeah outside of WOT it's going to come down to airspeed. I think the smallest venturis they make for the 50s is something like 40mm. Ime most of the bog at very low airspeeds you can make up for in the pump shot. With 47s and a 3.0 NA you would likely be running a 36-38mm venturi? Without a doubt you are going to get better control and performance with EFI. I was thinking you were considering carbs for some vintage racing class rules or something

So the pictures I posted earlier was a part that did move a bit...my fitup was perfect no gaps and I did 4 autogenous tacks. When I welded the vband in one go one of the tacks broke loose due to the thermal stress/strain and a 1mm gap appeared. When it fully cooled the gap shrank to something like 1/4 of a mm. I was able to retack and weld it back no problem but 1mm on that end of the tube moves the other end of the long tube a couple mm. I think I need to do like 8 or more tacks and work on my heat controk a bit more

Thanks @rossman. The catch can is an off the shelf Vibrant. I did cut and tig weld the bracket though. Originally I thought I could bend it but it turned out to be like 1/8" SS which was impossible to bend with my garage tools. I reused the firewall ground threaded hole and did a rivnut on the other side.

If any amateur welders like me were wondering in the future...what I found this past couple of days was if I shove a piece of foil into the tube and poke some holes into it I can fill just that section within a couple of minutes. You can see in this pic that the sugaring from the non-purged tacks is basically fully consumed when I penetrated through. They're still there as little black dots but that is because I was going conservative on the penetration because these pipes were not fully concentric and I was concerned about overdoing it as an amateur. On some test pieces I was able to fully dissolve the sugaring where my non xray eyes couldn't differentiate anything at least. For an exhaust this is probably fine and I don't need things to be pretty just to hold.

I don't have much to add, but since you'll likely be running at WOT most of the time and if it's an option in the budget OER is making the 50mm carbs again (they were NLA for years). The OER carbs are easy to set up and tune with the external and accessible pump stroke and float level adjustments, but once they're set you're not really messing with those parameters much anyways. Parts are also readily available but shipping from Japan has been expensive this past few years.

Was cleaning up some albums on my phone and realized I never posted the turbo fuel system setup. Maybe someone can find this helpful. I decided to do -6 feed and -8 return with an in-tank 255 pump bypassing through an aeromotive regulator. I had considered a 270 pump as well but didn't see it as necessary. Based on my research this should support 600whp on carbs which gives me some headroom. I fabricated the lines from basic SS tubing, AN flared connections, and limited braided SS softline use just at the small section by the tank and from the fuel logs to the carbs. Most of what I saw online for blowthrough/nitrous carb fuel setups were big v8 guys but maybe someone will be searching and find this in the future as well for sidedraft carbs on an inline 6. If I decide to go itbs later this setup will support that as well. If I was going to do the setup again I'd run the lines out of the tunnel for safety but I got to the point where everything pressure tested out good and I wanted to get the car back together by this summer.

Had a bit of time to work some small items today. Kept welding and fabricating the exhaust. I have half of the midpipe tacked out and half of it welded but it's been hard to find solid blocks of time to make good progress. Slowly but surely it's getting there. Also got the cold side piping in so I profiled and chopped the tubing in preparation for welding. I still can't believe it came in so quick, I've been used to waiting weeks or months for parts lol. As I suspected I was able to get good angles and clearances with 2x 45s trimmed. Now to order a bead roller. The weather is improving too so time permitting this weekend I can paint my cowl section and get the windshield back in.

Yeah I did some test pieces over the weekend and any sugaring from the small tacks is consumed on full penetration. Really I shouldn't be penetrating through to the other side on tacks but that is mostly due to alignment (ex partially cut mandrel radii where the tube ends arent perfectly concentric so there's only 1/2-2/3rds wall thickness joint to joint at some areas) and my lack of skill. Since I'm just a hobbyist I'm still trying to find ways to save any gas especially with the way prices are nowadays. High priced gas prices to drive to get more high priced argon adds up. I've been thinking perhaps for the longer sections where the welds are close to the ends of the tube I could crumple an AL ball with some gaps around the edges and shove it into the pipe to produce a smaller argon "chamber" as opposed to filling the whole pipe every time. Either way I'm about 1/2 done with my first full custom SS exhaust project now so I may as well keep experimenting and learning As an aside another reason I've been going through so much gas is I've found SS can really move around a lot when welding. So most of the backpurge gas I've used is due to purging the pipe, welding a bit, then walking away to let the part cool. I've found the part doesn't move much when I do this. If I could weld an entire section in one go instead of constantly coming back and repurging then I could save a lot of gas

Yeah I had some time to think about this and research more as I was waiting on filler. I'm going to backpurge the rest since I've already gone down that path but I'm not going to go crazy like the downpipe where I backpurged the tacks and let the purge run for like 10 mins until there was 0 air left in the pipe...I burned through like 1/2 of a 145cu ft tank just on that part alone. From my research some air left in the pipe is fine. There will be some discoloration like blues and whatnot but no sugaring and not critical on the exhaust post turbo

This morning I trimmed the hot side charge piping to fit. I'm happy with the clearances but need to purchase a bead roller to dimple the ends and prevent tube blowoff. I could also run some beads with the tig. For the cold side, I eyeballed that it'll take 2x 45s so I ordered the pipe and was promptly hit with a warning message for transportation delays/supply chain issues...hopefully I won't be waiting months for that 😂 I also fabricated a plate to hold the headlight relays and fan controller. I think I've probably made something like 20 random brackets for this build from bending to welding using scrap materials I had laying around the shed for house projects and my wife's garden. I now feel confident in my abilities to fabricate a bracket for any occasion LOL Got some good news as well that my 308l filler should arrive today...so now I get to clean up my cutting, grinding and welding stations for stainless exhaust fabrication again since I switched to AL while waiting...

Some rough measurements on the hot side I'll need to chop and shorten on two sides of the run. On the cold side into the surge tank I'm still not sure if I'll attempt to make some pie cuts or just two angle cuts to line it all up. The good thing is now I know everything will fit but it'll be tight.

A week and a half ago I attempted to source some 0.045 308L filler wire to finish the exhaust. It turns out the smallest quantity any local supplier around me sells is 10lbs. So I found a 1lb bundle on Amazon and I'm still without filler with a delivery date of next week due to trucking delays 🤬. Oh well. This past week I wrapped up the rest of the plumbing and cooler bracketry for the car. On the frontend the 10AN SS braided really does not like to bend. I decided to fabricate a bulkhead to ease the oil cooler routing. There is a small air gap between each component and my AC condenser fits in there nicely with all the fittings as well. The packaging is extremely tight. This weekend I'm going to start modifying the charge piping to fit. That is the last major component in the engine bay, then I can finish relooming the harness to ensure it clear everything and begin filling fluids. Edit: just realized after posting the photos I also pulled off a bunch of parts to have them zinc plated. Also refurbishing the JDM fairlady grille. Not really turbo related but I figured the inspection light, hood latch, etc. would brighten everything up a bit

Lol no doubt, I was just curious if anyone had modeled or tested it. It sounds like no. I was a licensed and practicing fluid/thermal dynamics engineer for a decade so I understand the core concepts and have used all the tools. Nowadays I just work on my Z and other cars for fun but not at that level of getting into these details again...yet 😅 Yes some of these pics are likely from Alan, they came up in Google as I've been looking at the undertray on and off for a few years. I'll gladly remove them if he asks but I'd be curious his take as well. Hopefully I didn't stir up the pot there, at the end of the day these are just hobby cars for most of us and we're all enthusiasts

That is unfortunate. Sounds like a lot of strong personalities. What we do know is a frontal undertray was wind tunnel tested and produced at some point in time by Nissan for racing/homologation purposes. I would think there would be some benefit otherwise the modification wouldn't have made it into production. I am curious why it wasn't paired with other aero but unless we find the original engineers from the 60s we may never know. It would've been nice to quantify those benefits, and how those benefits stacked or detracted with other aero but perhaps we'll get another go at it someday in the future... Edit: maybe next go around show the wind tunnel people the actual Nissan racing homologation papers and wind tunnel test pics for the parts. There must be a reason why they went through all of the trouble right? 😁

Was a full frontal/engine bay undertray from the front valence to the firewall ever tested (similar to what the z432r had)? Most cars I've seen with front aero use an air dam or chin spoiler but omit even the splash tray. Or they run a splitter just to cover the area under the valence but don't bring it further back. I recall seeing some pictures of Nissan wind tunnel testing some part scale prototypes to develop the full frontal undertray for homologation purposes? I don't believe they paired that with a front splitter or air dam, but the part was actually produced and there are some repro's of them in Japan. Found the pictures. There are a bunch of them testing various aero for the 432r as well including the rear spoiler. Really interesting stuff

I have been backpurging everything for the full weldouts. I would say the welds aren't underfilled, but I'm also an amateur so to be honest Im not sure. Before moving and starting back in on my car this past year I hadn't tig welded for at least 10 years...so I've been re-teaching myself how to tig on critical components of my car 😂. I was focusing more on full penetration and heat control. For the downpipe I backpurged all of the tacks and welds. For the midpipe I started tacking without backpurge and got a couple of tiny dots of sugaring which I'm still conflicted if it matters for an exhaust maybe 3 feet post-turbo. I plan to backpurge everything for the full weld outs. Edit: Good call on the weld bead profile. I took a look and some are flush, some are raised. I am somewhat consistent but not consistent enough. I think I need to focus on that as well and perhaps push more rod into the puddle as I go.

Still waiting for materials and some solid blocks of time. I had an hour last night so I mounted the boost gauge. Originally I was going to use a channel in my Stack integrated tach to run it, but the channels are now being used by fuel pressure and oil temp. I wanted to keep the vacuum line off the engine because there are already like a dozen vacuum lines in that area for all of the other turbo items so I moved the signal source to the firewall between my vacuum log and the 1 way brake booster valve. I also had the challenge of nobody having the right fittings I needed so I silver soldered two fittings together to create the boost gauge feed. Finally I fabricated a bracket off the center console dash bracket to position the gauge in DS footwell area. It's easy to read at a glance and outside of the car you can't see it at all which was the intent 😈 Man nothing is ever easy on this car...but one small project at a time it's getting there

@DuffyMahoney yeah thinking about it more as I own my argon bottle and get discounts at my local gas supplier...another $100 of argon won't break the budget when I'm already a few hundred in stainless tube. I am curious how many actually backpurge their tacks for exhaust work. Some youtube vids show most don't. I can understand why for the food industry you wouldn't want and defects or crevices in the welds at all

Based on my limited research it's advisable to backpurge everything including tacks for SS like you'd do for critical operations in a nuclear plant or similar where they xray all of the welds, look for tungsten inclusions etc. For automotive applications it seems pre-turbo you'd want to backpurge everything as well to limit the chances of cracking over extreme heat cycles. Post turbo is less critical. I fully backpurged my downpipe from tacks to welding but man that took a lot of argon. For the midpipe back does it really matter so much? Specifically for tacks, I'd still be doing backpurge on the full weld-out

One thig specific to the turbo packaging that I had to overcome was rerouting the speedo cable to clear the downpipe. Nowadays more people are probably opting for gps or other sensor methods but maybe someone can find this helpful. When I redid all of my brake and fuel lines in stainless I decided to move the clutch hardline off the firewall via a bracket as I preferred that run over the OE configuration. I had some aircraft adel clamps left over from other routing so I routed the cable following the OE hangers except in the portion above the downpipe where I brought it up and over. The result is more of a tucked look and hopefully no melting.

I'm doing a 3" right now on my Rebello 3.2 Stroker Turbo. I'm documenting what's going into it in the turbo sub forum. If I was doing a 3.0 NA I would still go big and free flowing, maybe even oval pipe if it's in the budget Edit: If you're looking for something off the shelf High priced, Kameari makes some big pipes and headers which are artwork. More moderately priced there is Zstory headers and exhausts and they're something like 2.5". I ran their muffler before and it was well constructed. Lowest cost MSA isn't a bad option. I ran their exhaust and 6-1 header for years. I was running triples NA and kept popping the baffled turbo mufflers at the seams on the overrun so I upgraded to a magnaflow straight through then the Zstory straight through twin stack.