Triple Blowthrough Turbo

[Dat73z]

Yeah I found that out the hard way when I pulled the windshield and the previous glass co gouged and siliconed the entire windshield frame resulting in rust. Oh well, it's been repaired. 

 

This morning I woke up early to keep working the bracket a bit and make it look a bit nicer. I'm going to radius the edges a bit and maybe add some design elements like speed holes before calling it good.

 

I also realized by cutting close with the bandsaw and trying to save some sanding time I created a bunch of extra work for myself blocking out the gouges for a brushed finish. I'm not a professional fabricator so I guess this will be a lesson paid for in extra time

[AydinZ71]

Brackets look good  what’s the AL alloy? 6061 machines a ton easier with less deburing, but it won’t bend easily without annealing. I use snips on AL precisely because my cut-off wheel makes a mess of the lower alloys. 0.08” 5052 will bend at that thickness, snips will still cut it, but it’s rigid enough not to warp the hell out from the snip. Give it a shot next time  

[Dat73z]

Thanks @AydinZ71. Honesty I'm not sure the alloy. I had a bunch left over from my wife's garden...reinforcement for some planter boxes I made and hangers for flowers. So I used all the scrap AL to create all the custom brackets I used for this build. 

 

It doesn't sand or weld very well at all and putting a uniform brushed finish on it was a pita. It's also like 1/8" thick so I'm limited to hacksaw or bandsaw for cutting and it doesn't like to bend at all. I honestly can't even remember where I got it, probably Home Depot or Lowes. 

[AydinZ71]

For a small job, it works  just use whatever scratch you have. If you have Time and interest, buy a small sheet of 30-series, 50-series, and 60-series and just play with them. You will be shocked at how differently they all behave. The last two numbers (“T6”) is the heat treating. Ideally you want that number lower if you plan to bend/manipulate it unless you feel like annealing it yourself. 
 

when I first started fabricating, I kinda ignored all these details and just sent-it. Over time, realized understanding the material better saved a heck of a lot of time. Just shootin-the-**** here, but if you ever want to do a ground-up project play around with everything. Price really isn’t a factor but n the quantities we are talking about. I bought one 12X48” sheet of 20-gauge stainless for like $30 and still have not used it all. Made several small brackets, battery hold-down, etc. and saved time by not needing to coat any of it. Stainless is underrated in fabrication IMHO. If you use thin enough stock and are willing to manipulate & weld it, often not much heavier than AL for the same job. 
 

You are way ahead of me on welding though. Your exhaust work looked great! I have yet to load a cord of stainless wire in the mig and give it a go on my own stainless exhaust. I don’t have a TIG, or experience with TIG yet. 

[Dat73z]

💯 I would've saved hours, probably days if I had purchased the correct raw materials upfront. Good info on the various alloys...I'm actually a degreed and licensed engineer with a background in mechanical/materials but I'm only practicing electrical now. If it hasn't been apparent I've sort of just been sending it on this build in my spare time and mostly whatever I have on hand 😂

 

In terms of tig welding there are lots of affordable machines out there now. I started on mig as well and besides the additional and to me at least annoying prep/positioning that goes into a quality weld I prefer tig. You get a lot more control. If it's in the budget maybe get a cheapo tig machine and make some stuff. It's not difficult to do some functional welds and with your background in mig think you'll pick it up really quickly. Worst case your welds look like 💩 and you grind it down like you would with the mig lol

[Dat73z]

Final weekend update on the turbo build. Just wrapped up the coolant overflow mounting. I was thinking to do some aesthetically interesting things to the bracket but ultimately kept it simple with radiused edges and a brushed finish mainly because I kept getting distracted so function over form. 

 

Hopefully my radiator cap comes in early next week so I can do the final adjustments to the cooler packaging and move forward with final assembly. 

 

Next week there are a couple of non turbo related items I need to address but I think the objective will be to get the engine ready for the first fireup. 

[Zetsaz]

3 hours ago, Dat73z said:

Final weekend update on the turbo build. Just wrapped up the coolant overflow mounting. I was thinking to do some aesthetically interesting things to the bracket but ultimately kept it simple with radiused edges and a brushed finish mainly because I kept getting distracted so function over form. 

 

Hopefully my radiator cap comes in early next week so I can do the final adjustments to the cooler packaging and move forward with final assembly. 

 

Next week there are a couple of non turbo related items I need to address but I think the objective will be to get the engine ready for the first fireup. 

 

What overflow tank is that?? Looks like a nice fit. I might try moving to that on my mishimoto radiator.

[Dat73z]

@Zetsaz yeah it fits pretty good, pretty happy with how it came out 👌

 

It is a champion 2"×10". I got the idea off some posters on FB. The guy who sent some installed pics had a slightly diff mounting config and what looked like the larger 2"x13" bottle 

[Dat73z]

@Zetsaz Here's a better shot of the clearances. I think I recall the mishimoto is slightly smaller so you might be able to tuck it in even tighter

[AydinZ71]

ME here as well  Not licensed (didn’t want to be), started as a project engineer and worked as a PM for years. Now an engineering consultant. A lot of my work on oil/gas/hydrogen was transferable to cars from material science to thermo/process. I geek-out on details. What part of CA are you in? 
 

yeah I need a TIG for sure. I’m almost done welding on the race car though, so I kinda just want to get it done and start fresh on the next one. 

[Dat73z]

Nice! I tend to geek out on details when I'm working but when I'm doing my own projects my brain is 99% unplugged which is also why I tend to go through a bunch of revisions and whoopsies 😅. I'm in the SF Bay but formerly LA/OC. 

 

Tonight I started fitting up the lower rad hose. I started by trimming the 280z hose 2" in the vertical plane and added the coupler I made. Then I realized the assembly is way too close for comfort to the oil cooler lines and alternator fan. 

 

The Wizard cooling radiator is much larger than the Mishimoto unit. I have a few options here I believe.

 

I'm going to start by trimming the 280z hose a bit more to see if I can pull the vertical portion of the hose away from the oil cooler lines/alternator and towards the rad. If that fails, I have some scrap AL tube and I was thinking of hardlining the entire run and having just 2 rubber or silicone couplers at either end. The 240z hose is just dimensionally wrong due to the increased size of the rad. 

 

I feel like every time I do anything on this car a bunch of custom fabrication is required but the build goes on

[Dat73z]

And after more measurement and mockup with what I have on hand it turns out the 240z hose with a 90 from the 280z hose at the bottom with the AL coupler I made will work. 

 

It's not perfect but the closest point is to the fans. I figure when the fans engage or driving the hose will tend to move back towards the firewall instead of towards the fans. 

 

I wonder if my aftermarket 280z hose is a lot different than the OE 280z hose as the 240z OE hose runs a lot further forward to the rad before bending down. But I'm only $14 into it and I guess in the future I can just order a 240z hose, a 90 elbow, and reuse the coupler I made. 

 

I was kind of hoping I could use order a 280z hose in the future to trim but if anyone has pics of the OE 280z hose in their car please let me know. 

Edited June 14, 2022 by Dat73z

[Dat73z]

Last night I finalized the rad positioning. I was able to raise it 1/4" which left me somewhere between 1/4-1/2" spacing between my chosen rad cap and the hood bulge. It is now hopefully not coming out again for fitup. 

 

I also trimmed the coolant hoses to fit and installed the hose clamps. I can't remember why I decided to use the OE style clamps as there are better styles available but I think it was because I was sending a batch of parts out to zinc plate anyways and I already had them. 

 

On cutting the hose I have always struggled with making clean cuts so for this build I decided to change that and attempt to make clean cuts. 

[Dat73z]

With the radiator change fiasco out of the way I started back in on final trimming of the intercooler piping over lunch. 

 

Because everything is so tight on this setup I've really been trying to be considerate of serviceability, even something as simple as trimming tube. 

 

For the cold side I sectioned the run to give just enough clearance to swing out of the way of the upper rad hose. Otherwise I'd need to drain the coolant down and remove the upper rad hose to work on this section in the future. 

 

I need to do some final adjustments and bead roll the ends. 

 

[Dat73z]

This evening I got my hot side piping mostly finalized. I was waiting to complete the rad fitup before final trimming and I'm glad I did. 

 

The final clearances came out just about right. I did the final cuts to the charge piping on the bandsaw then using my new clean hose cutting skills trimmed the silicone coupler down a bit. 

 

The pipe needs to come back out one more time for bead rolling and maybe refinishing. Unfortunately during the past couple of years when I was moving around and couldn't work on the car I carried the piping with me with every move instead of putting it in storage with everything else so it has some nicks and scratches. Not sure if I want to put the time into that right now. 

 

I am also considering fabricating and welding in some bracing for the charge piping that bolts to the head but I need to do some more research on the pros/cons of that. I've seen a lot of turbo builds that run without it and some that do

[Dat73z]

So after a lot of reading on IC charge piping design, it seems: 

 

1. A bit of flex is good. Setups with bracing can crack out the AL welds for brackets and this is a known issue even for mass produced intercooler pipe kits/hardpipe upgrades. 

 

2. If bracketing and using silicone couplers, care should be taken to ensure that the bracket and chosen pivot point(s) doesn't create more issues with hose blowoff. 

 

3. There are other coupler options available similar to vband clamps but can be fairly expensive and adds fabrication time. Some are able to flex, others have no flex. 

 

4. If using silicone couplers, use high quality parts including at least tbolt clamps. By design, tbolt clamps do not provide even clamping force and can go out of round. There are other more expensive clamp options as well such as Murray clamps which are similar to what OEs use but with a constant tension mechanism. The best clamps have even tension and will not break or loosen resulting in boost leaks.

 

I'm leaning towards no bracing and running the tbolt clamps I have to keep moving forward. It seems all of the other options are basically more $ and time for an incrementally better result. Open to suggestions if anyone has thoughts, here is the worst case movement I get with no clamps on the hot side. The cold side is fairly constrained and short. 

Edited June 16, 2022 by Dat73z

[Zetsaz]

I run a mix of T bolt clamps and worm gear clamps right now because it's what I have on hand and they honestly work fine at my boost levels. I only have one support on the passenger side and it's to help make sure that the piping running under the engine doesn't dip more than the half inch or so it's already lower than the front crossmember. I would think with even shorter runs you don't need any bracing since it's fixed on one end by the turbo and on the other by the intercooler and brackets there. You should really only have 2-3 couplers between those spots which is enough to flex but still well supported so the entire length doesn't move much. 

If I upgrade any clamps I think I'll probably be using some higher quality worm gear clamps. I feel like the t bolts I have just occupy way more space than necessary, but better clamps will probably cost me close to $100 for every place I need. 

[Dat73z]

Yeah I was surprised to find that OE's basically run some improved worm clamps for even clamping pressure. I priced out Murray clamps and it's 1-200$ just for that, and HD clamps are like $100 each! Maybe someday in the future. 

 

I tested the tbolt clamps on my hot side piping and the movement is constrained to 1/4 or 1/3rd of what I had in the vid above when I'm really yanking on it. I'm basically at the point of having everything back together enough for a first startup so this will do for now. 

[Dat73z]

Tonight I wrapped up the bead rolling. 

 

It's been a really busy week but 15 mins here and there is bringing this to the finish line. 

 

This weekend I'm going to set mechanical tdc and on the distributor. Also see what base map Rebello ran the engine in on the dyno with

[Dat73z]

I used leftover silicone hose, clamps, and a barb fitting from when I was doing the turbo vacuum lines to plumb in the overflow tank. 

 

I forgot that I had ordered some new battery terminals as they were delayed for a few months due to supply chain but they came in earlier this week and also fit perfectly under my terminal boots.

 

I'll take this as a sign to start back in on the wiring. I rebuilt the harness a bit with all new connectors and a dedicated 12v feed to the fuel pump. With all of the hard parts in place I'm going to work on finalizing the re-routing of the rad support area wires around the cooler packaging + looming