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tfrasca's 142 Turbo Project

Congrats on the move - that looks like a great garage to get set up in. I'm still working on the layout in mine after almost 10 years...

Sweet 944 also, that must be a rare color, no? What about a 1.8T VW swap? I've seen a few and the end products look like a lot of fun.
 
I?m using the 600 series hanging pedals and mounting them to a frame like Kyle did in his wagon. It?s more work than I cared to do but I was never going to be able to get a booster or even just a dual-circuit master to fit in the engine bay so my brakes just weren?t going to work properly.

Oh nice. I may end up going that route. Im about to give up on building a manifold and just try to hack up a KL racing one to fit. But that'll make it so I can't run a booster and a dual master brake setup in the car may be my only option.

Congrats on the move - that looks like a great garage to get set up in. I'm still working on the layout in mine after almost 10 years...

Sweet 944 also, that must be a rare color, no? What about a 1.8T VW swap? I've seen a few and the end products look like a lot of fun.

Thanks, Chris. The garage is a little bigger than it looks in the photo, too. There's a bunch of space in front of the car. Excited to get it set up, 5-10 years from now!

Lots of engines make more sense, but the sound of a vr6...

Gave up on SAABs and settled for a Porsche smh :lol:

I really did. I had a friend look at an SPG in LA that ended up being a complete mess. Then I found a super cool 5-door 900 that had a B202 swapped into it and a bunch of 87+ running gear. Missed it by a day, and was prepared to pay more than it ended up selling for. I was on the rebound and the Porsche came up within driving distance of the new house. Had to.

For one thing, there's the sound!

Would love a Porsche that sounds like a wookie!


I've been looking at that kit. I keep telling myself I want a nice simple NA car though. Which is exactly what the 944 is currently. But a 3.6 vr6 would be fun. Regardless, I really hope I don't end up swapping it. At least not until the 142 is completely done.
 
It's been another few months and I guess I've made enough progress for an update.

I FINALLY, after three attempts, have made an intake manifold for this thing. This one doesn't have nice velocity stacks inside and the runners are quite short, but at this point, I'm just glad I was able to stick the metal together.

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The plenum is kind of a flat box, similar to the Ford Cosworth manifold, but with more volume. It clears everything, and should do the trick.

At this point, I could keep noodling on things with the mock up block and head in place, but I think it's time to pull the head and get it rebuilt (looking at you, culberro) to really force me to get it done. The bottom end is at a machine shop being bored for the forged pistons.

Once the engine comes out I can think about:

  • Finish welding motor mounts
  • Run new brake lines
  • Put .80 5th in the T5
  • Run fuel lines
  • Figure out IC mounting/air direction for coolers
  • Mount oil cooler
  • Mount new/different radiator and reservoir

So yeah, I'm not even close to finished, but steps are being made. Some time in the first half of 2022, that's my new goal.
 
Want some cam blanks to make the most of that (now) high RPM setup? There's a cam cutter near your new whereabouts...
 
So, my engine has been at the machine shop for a couple months, and I've decided to completely redo the cooling stack on this car. On the 8 valve setup, I used a Northern Radiator that never really seemed to keep up. The car got really hot a few times, which may have contributed to the cracked block. So now I have a bigger Griffin radiator. I'm hoping it helps. I had to do all sorts of hackery to get it to fit. The lower core support that I made last year was low enough to fit the Griffin radiator, but I had to cut more width out of the front of the frame rails. Like this:

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Then I had to make new vertical supports that bolt to the frame rails and run up to the stock upper radiator support, which has now been cut up quite a bit. Here's the new radiator in place:

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Moving the radiator forward and down frees up space for a proper fan and shroud. I designed some parts in Illustrator and had Send Cut Send cut them out. I'm really pleased with their work and the whole ordering process, but now I know more about putting holes so close to bends. I was this close to having to scrap the whole thing, but some persuasion with the dead blow salvaged it.

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I welded it up, and welded some attachment points with rivnuts onto the radiator, and it seems like it'll work. The square holes are for rubber flaps that I'll rivet in later.

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The inlet is 1.5" and the outlet is an angled 1.75", so I'll need to sort that out, but for the most part, the radiator upgrade is done.


With that in, I decided to rearrange my eBay intercooler and stock 240 (I think?) oil cooler. I welded 90 degree bends onto the intercooler inlet/outlet, and -10 fittings to the oil cooler. I had planned on mounting them like this:

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But then I realized I was hiding an already inefficient 21x7x2.5" intercooler behind the front body panel, so I started to think about better intercooler options. Packaging and cost led me to this 20x7.8x3.5" Mishimoto core, rated for 575 hp (whatever that means). I'll be mounting it in the grill opening, and moving the oil cooler down behind the body panel, probably with some more speed holes, or other ducting. But I feel good about an intercooler that's properly sized for my turbo.

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That brings me to end tank design. I have some room to play with, but I keep coming up with a simple design like this:

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The offset inlet and outlet would be slightly easier for packaging the charge tubing, but mostly it seems like not putting them directly across from each other would help use more of the core. Maybe pressurized air meeting the relatively restrictive core would disperse across all the rows, but it makes sense to me that the rows furthest from the in/out would see less flow.

Speaking of that, does anyone know if adding baffles to direct some air to the further rows is actually helpful? I've seen some baffled cast end tanks, but I assume some actual CFD analysis goes into that. I'd like to try bending up some simple .125 aluminum baffles, but I'm no scientist and I may end up hurting flow more than anything. Thoughts?
 
hey we're doing the same stuff right now, looks good. Fitting the monster Ron Davis and Garrett into my car is a fun little puzzle.

Personally I decided without trying to model it I was better of KISS and not putting anything into the flow path. I have talked about this with the guys at work who do the heat exchangers and honestly they don't have much to offer when they can't let the computer tell them what to do, then they just start talking about hydroform molds and high temp additive crimp-on tanks and it's not helpful advice for me :lol:

What are you going to use for the material for the tanks. I got some free 6 and 10" round tube we're playing with to make the front of the tank a nice radius (rear facing in/out), also bought a sheet of 5052. Both are .100". I see a lot of guys using .125" but it seems like overkill on a relatively small tank with minimal flat area?
 
Yeah, keeping it simple might be the best move without any modeling capabilities.

If I was going to do rear-facing in/outs, I'd want to try to make a curved front wall, for sure. But I want to try to keep the in/out to the sides so I can still slide the intercooler into place without having to remove the radiator or cut more out of the nose panel.

I got a sheet of .125 5052. I can bend in in the press brake, and it weld really well. Most of the aluminum welding I've done has been on .125, and I feel more comfortable using it for something that'll see boost pressure.
 
Wonder if you could make backyard cast end tanks for the IC. Make them real nice and smooth like the group a intercoolers.
 
Wonder if you could make backyard cast end tanks for the IC. Make them real nice and smooth like the group a intercoolers.

I've always been mildly interested in casting, but I'm not ready to start learning that. The trial and error involved would be crazy.

Plus I'm just now getting the hang of TIG welding aluminum, and I'd like to keep that going.
 
Packaging and cost led me to this 20x7.8x3.5" Mishimoto core, rated for 575 hp (whatever that means).

Intercooler HP rating was something I was fuzzy on for a long time, but talking with an engineer who designs them recently cleared it up for me. Now I can spread the gospel.

The short answer is: the HP rating is related to airflow capacity.

Longer answer: at a given set of ideal conditions for ambient temp, pressure drop across the core, effectiveness %, and hot air inlet temp, the core will have some maximum flowrate. Take that flowrate and multiply it by a standard constant and you have the horsepower rating.

Since it isn't clear (and may not be meaningful) which exact values for the boundary conditions are being used by the manufacturer, I'd argue that the HP rating is mostly useful as a max flow comparison value between different cores from one manufacturer.

The standard assumed pressure drop is probably pretty low, like on the order of 1 to 2 psi across the core. That would be awesome in practice, but of course you need end tanks and they are responsible for pressure losses too, in fact usually about equal to the drop across the core itself. So 3 to 4 psi across the whole cooler is a good (but reasonable) target value. Once it's built and installed you could get pretty close to measuring this by just piping in a 2nd boost gauge between the compressor outlet and intercooler inlet.


Speaking of that, does anyone know if adding baffles to direct some air to the further rows is actually helpful? I've seen some baffled cast end tanks, but I assume some actual CFD analysis goes into that. I'd like to try bending up some simple .125 aluminum baffles, but I'm no scientist and I may end up hurting flow more than anything. Thoughts?

It's going to be pretty difficult to answer this without CFD analysis. There are so many different variables, not just in the cooler design but the operating conditions in your application also.

Adding vanes to the end tanks is always an effort to help distribute flow more evenly across the core. So if you were able to visualize the flow and get a good prediction for outlet pressure drop and outlet temp, then you could weigh the effects of adding vanes to the end tanks. I don't know this for sure but I'd assume adding them to the inlet tank would be most helpful, and you'd want the vane to get close enough to your round inlet to effectively split the flow and direct it to the under-used part of the core (not just act as a flow barrier).

Without CFD you could build the cooler without the vanes, do some thermal imaging while running on a dyno or other static test stand (for example), and then add vanes to direct more flow to the dead zones that you'd likely see. Then test again!
 
I got a chuckle when I was core-shopping and read a Garrett article with a lot of great, wordy theory, formulas and math and in the end they summed it up by saying "generally you should select that largest core that can be packaged in your application."
 
I got a chuckle when I was core-shopping and read a Garrett article with a lot of great, wordy theory, formulas and math and in the end they summed it up by saying "generally you should select that largest core that can be packaged in your application."

It's funny but true. That was probably written either by me or one of my long-time colleagues like 15 years ago. It's tough to give super specific advice when your target audience doesn't have the resources (or desire, usually) to fully apply that advice and get clear answers. Without the analysis tools it doesn't really help.

The gist of it is, if you can't do a meaningful analysis for CAC sizing :-)rofl::roll:), then err on the large side since that will tend to help minimize both outlet temps and delta p across the cooler.

EDIT: everyone knows that a larger CAC is a better CAC.
 
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Well I can pretty much guarantee that I won't be building the intercooler, testing it on a dyno, then cutting the intercooler apart to add/change internal diverters. If I do add anything, it'll be more of a feel-good exercise than anything else. With no science whatsoever, it seems like something like this would at least help put some air through the upper rows. I just divided the 2.5" inlet into thirds, and the 7.8" core into thirds, then bent the diverters into shapes that seem better than straight lines. I could see a low velocity area under the top part of the top diverter, but again - no science.

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Well I can pretty much guarantee that I won't be building the intercooler, testing it on a dyno, then cutting the intercooler apart to add/change internal diverters. If I do add anything, it'll be more of a feel-good exercise than anything else. With no science whatsoever, it seems like something like this would at least help put some air through the upper rows. I just divided the 2.5" inlet into thirds, and the 7.8" core into thirds, then bent the diverters into shapes that seem better than straight lines. I could see a low velocity area under the top part of the top diverter, but again - no science.

cGHB6lJl.png

That looks pretty reasonable to me, including the approach of splitting the inlet and the core into thirds. If you want to evaluate the restriction after the fact, plumbing in a pre-cooler boost gauge and comparing to post-cooler boost will give you a rough idea of delta p. If the difference is something <5psi then I would call it acceptable.
 
Well, I got to looking at this intercooler, and realized that a rear-facing in/out setup might not be so bad. I started tinkering with some stuff on my lunch break, and accidentally made an end tank. Unfortunately, because this was just an experiment, I didn't bother to trace my flat parts, so now replicating it on the other side is going to be a huge pain. Still not convinced this is the best way, but I don't hate it.

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I could have put a diverter to send more air to the back of the core, because as-is, I think it'll favor the front, but I decided I probably couldn't pull that off cleanly.
 
A bit more work on this intercooler. I've wanted to learn how to model things in 3d for a while. I work as a graphic designer with Adobe 2d programs everyday, and I figured it that skill might help with modeling software. Nope. It took me 2 days to make this extremely simple end tank that I could have done with cardboard in 2 hours. But it's interesting to me so I'll keep messing with it. It's pretty cool to be able to print 1:1 drawings with center points and bend lines and such.

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So, I have this crazy looking intercooler now with a backdoor inlet tank and a more standard outlet tank. I was going to make the outlet similar to the inlet, but even with the curve, the air would still have to make that 90?, slam into the back wall, and funnel from the big tank into the 2.5" outlet. It seems like this outlet will have a simpler air path, and the 90? will happen once it's already made it into the final diameter tube.

pgmBZBkl.jpg


Anyone have any thoughts before I weld it all together? I also made an end tank with the opening in the center, and was thinking about using that for the outlet, but it wouldn't line up to the throttle body as well, and I don't know if centering the outlet would flow that much better anyway.
 
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