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Nice work on the removable core support. Few things bring me joy like watching people design for future serviceability.
Thank you, I'm glad someone appreciates this work.
I haven't shared much about my '78 Porsche 928 restoration project here and to be honest it's been on the back burner for several months while I push to get this car out of the garage. I knew going into it that German engineering was incredibly different from the Mazdas I'm used to. Even as a first-year model, before it became a demonstration of all the crazy technology Porsche could dream up, the 928 is a lesson in leaving serviceability out of design decisions. Did you know that it's impossible to remove the brake booster on a 928 without first pushing the pedal to the floor, then using vice-grips to hold the piston rod in place? Otherwise the pedal rod extends too far and there's no clearance to get it out.
Anyhow. Yes, serviceability is something I think about. Perhaps even too much. But when you've done it and it saves your butt later down the line, what a great feeling!
edited to add: of course I placed the order for the cross-flow this morning. because i'm an addict.
I am unimaginably impressed with the quality and thinking that went into this. First off, I was planning to cut some sheets of alu or cardboard to protect the fins while inserting and removing the radiator. But wait! There’s already a piece of blue coroplast included for just that reason. Oh crap, I need more hose for the new rad cap location! But wait! It’s already in the box. Along with orange hose clamps for routing. And new clamps for the rad hoses. And the twin drain plugs already have paint marks to show they’re fully seated.
This is why I buy so much from SuperMiata - they think the way I do, only better. If SuperMiata had designed the K swap, I wouldn’t have had nearly as many issues as I did thanks to the underwhelming thinking by KMiata/KPower. I know I sound like a shill for these fine folks, but they really are good people, solid engineers, and excellent product designers. Hard to find a company that does all three of those well.
I also like their definition of a “small” hammer.
That is a honking big core. The coroplast cover went back on right after I took this photo.
This was my “d’oh!” moment. The radiator cap is directly in the path the intake used to take.
For now, it’s not a problem, I’ve just laid the intake in the other direction. The original intake wasn’t the best solution, so I’m willing to modify it. There will be much noodling over the solution. I’m thinking that the easy button would be to do a large NACA duct in the hood that feeds right into the throttle body. But there are better options. I need to get the hood on so I can check clearances for more ideas.
This was my “d’oh!” moment. The radiator cap is directly in the path the intake used to take.
For now, it’s not a problem, I’ve just laid the intake in the other direction. The original intake wasn’t the best solution, so I’m willing to modify it. There will be much noodling over the solution. I’m thinking that the easy button would be to do a large NACA duct in the hood that feeds right into the throttle body. But there are better options. I need to get the hood on so I can check clearances for more ideas.
A 45 off the throttle body should get it past the radiator cap (barely) if you still want to get into the headlight area. On my setup with the filter getting air directly from the airdam inlet, I consistently see IATs no more than 1-2*F above ambient.
A 45 off the throttle body should get it past the radiator cap (barely) if you still want to get into the headlight area.
I need to do some testing and thinking - I'm running the Bosch DBW throttle body and will be replacing my DIY adapter with the Winning Formula product that uses a short length of silicone tubing for vibration damping. It's going to be a bit longer than what's on there now and definitely longer than your cable throttle body.
I could use a 45 degree elbow instead of their short straight coupler - it would add a small amount of throttled volume, but would get the turn started nice and early.
Thanks for the reference image, I'll keep coming back to it and will likely have followup questions...
Thanks for the kind words, glad you're liking the radiator. We've been putting a lot of effort into making our products more customer-friendly. For years Xidas didn't come with any form of instructions!
Laughed out loud at the small hammer, never noticed that little easter egg.
I spent some time in the garage last night playing with my intake tract.
First off, the Winning Formula Vibration Solution DBW Adapter is the bees knees. Seriously impressive work, even by my crazy standards. All eight bolts came with Schnorr washers already installed. As you can see here, there's a tiny notch cut out of the lip here so that it's possible to insert and remove this bolt without any drama. Fantastic level of attention to detail, excellent finishing. They even include spare O-rings, instructions with torque specs, and they clearly list the replacement O-ring sizes (which are industry standard sizes), including the McMaster part number. They've clearly got a ... Winning Formula ... for product development!
The overall length of the adapter plus Bosch DBW is pretty serious. I've ordered a 45 degree silicone bend, which I'll use in place of the included straight tube. There's just not enough room for a decent bend with the Crossflow in place. After some noodling last night, I was surprised to figure out that I could do something similar to what @Roda did without having to do any aluminum welding (I hope). Parts are on their way now.
Since I haven't seen this figure anywhere, I thought I'd share that from the front edge of the intake manifold to the front edge of the Bosch TB is 4.2", more or less. There's some parallax error in this photo, so please trust that this is the distance that I was measuring.
Even though I don't see or smell any fuel leaks, I feel like the fuel pressure falls pretty dramatically after the initial priming run by the fuel pump. I don't think it was falling this fast before the new engine. While I had the throttle body off, I noticed some fuel smell and saw some very minor fuel puddling inside the intake manifold. I need to look at last year's logs to see if this is a change from the prior state. Not sure why this would be happening, but I should figure out first if it's actually happening at all.
After two separate orders to SiliconeIntakes.com, here is the working intake solution for K24 + DBW + Winning Formula + Crossflow:
60 degree silicone elbow with 1" trimmed off of each end
3.25" to 3" silicone reducer with some trimming from the larger end. This was leftover from the original build, the trim is not strictly necessary.
45 degree bend aluminum tubing, 2 foot length. Lots of trimming required here, but the 1 foot length would have been too short on the long leg.
I still need to add a couple supports to the aluminum tube, as well as drill/weld the IAT sensor bung. I'm hoping to have a local fab shop do the welding for me this week so I can go to an autocross at Sonoma this weekend. We'll see how the week goes. I really want to shake this car down a bit before I put it away for the winter and roll the 928 into the garage.
I tried valiantly to make the hole as neat and clean as I could, but of course I ended up with something that was oversized and lopsided. It's not the end of the world and I'm hoping it'll look better once I put some edging on it or something.
There's quite a bit of clearance here - I can actually remove the rad cap without disassembling the intake!
As you can see, the 45 degree pipe comes out at an odd angle. I think a 70 degree pipe would have been perfect, but the closest thing I've seen is a 75 degree pipe that costs more than twice what I paid for the 45. This is good enough.
The first version used a 45 elbow and a 90 degree pipe. Even with as much trimming as was possible on the silicone elbow, that put the throttle body way too close to the rad cap. The hood clearance was also an issue here. The 90 degree pipe was a mistake, I should have known better.
Let me now tell you the story of the most infuriating sticker in the world.
As you can tell from the state of my garage in the background of all my pictures, I am not the most organized person in the world. Sorta. Somethings are hyper-organized, some things aren't.
Back in August, I ordered a new clutch disk from SuperMiata. I threw in a SuperMiata windshield banner because Ed has been great to me over the years and it's finally time for me to pony up and advertise for them. I mean, it's seven bucks or something, I can swing that! The parts arrived and I kept the banner with some other stuff on my dining room table (slash parts storage area).
Fast forward to a week or so ago when I finally got around to cleaning the windshield so I can actually see where I'm going. Perfect time to slap the banner on! The banner is nowhere to be found.
I've now torn apart the dining room/storage area at least three times. I've checked the trailer, my daily, the garage, my office, the spare bedroom/storage area. No dice.
I've found a headphone case that's been missing for months. I've thrown out piles of old mail and other packrat crap that my cleaning ladies have neatly organized during their biweekly attempts at managing my chaos.
All for a cheap sticker that I'm too proud to just man up and re-order.
We all know that the instant I order and receive a new one, I'll find the original. I'm just too damn stubborn! It's got to be around here somewhere...
Edited to add: my dog changed in her response to my insanity. At first she was excited that my cursing and ranting and digging through boxes was a sign we were going on a trip, or that I was finding her a new toy. Now she just rolls her eyes and gives me a pittie's usual skeptical look when I start pawing through boxes ... again.
A couple months before I blew up the original engine, I ran it on a NASA dyno to get an idea of the power I was making under their classification system. My best run (of three) was 207hp and 161ft-lbs.
My calculations show a NASA horsepower average of 197.84 hp, round up just touch to 200. Right now, with me in the car and some fuel on board, I'm running at 2222lbs. Call it a 2200lb comp weight if I add a small amount of ballast for safety margin.
With my current and future mods, this leaves me in a funny place for ST/TT4:
If I were made of money and could afford to run Hoosiers, I would have to give up about ten horsepower to be right on the mark.
If I were to run less sticky, more affordable tires like RS4, I would have room to add 20 horsepower, if I can find it.
The Maxxis RC1 is in the same category - not quite as cheap as the RS4, but still cheaper than purple crack.
If I were to run the equally-affordable RT660, that would allow me to add 7hp.
If I ever get my head together and start competing, I'll be running locally against national champion ST4 competitors in E46 M3s who are detuned down into the 270hp range. With my skills, anything I drive will be like bringing a pool noodle to a gunfight. Twenty extra horsepower seems like a pretty nice chunk of power, but I have to assume that the Hoosiers really are that much better, right?
Too nice of a day to be stuck indoors. I’ve been wanting to get another couple blasts around the neighborhood under my belt, mid day on a Wednesday seems worth putting off the work I should be doing.
I’m starting to get concerned about my coolant temps. Idling with the fan on does not seem to lower my temps at all, and just idling will get the coolant temp sensor up in the 190s, which quickly becomes 200+ when just motoring around at part throttle.
I was pretty sure I got the last of the air out of the system with the last go around, but I’m letting the engine cool off with the nose raised to put the filler neck higher than the back of the block. I’m starting to regret not replacing the water pump when I swapped the motor.
Looking at info and not just my fear of numbers that begin with 2…
Quick search says thermostat isn’t fully open until 190F. Fact check with my spare thermostat shows 78C printed on the plastic housing. (170-something in American units)
I took the car out to an informal autocross/drift event yesterday to shake things down. After a few runs, I parked to give the car a once-over and while showing the swap off to a paddock neighbor, we saw this. Apparently this hose is not rated for vacuum.
Shoulda anticipated this. V3 of the intake is needed.
A couple more notes - the thermostat may be a bit sticky, or maybe it just hasn’t broken in yet. It started off with coolant temps up near 210 at idle, with the rad hoses warm, but after the first pass or so it fell back down to about 185 at idle. Not sure what, if anything, I should do.
Still not sure how it happened, but I somehow knocked the air filter off the end of the intake on my last run. I need to add a lip or something on the aluminum pipe to keep that from happening again.
Overall, I’m happy with the car. I have to look over the data, but I think I need to add a quart of oil as on my last run I may have seen a brief oil pressure alert. I’m at 6 quarts right now, 7 seems excessive given my measurement of the pan volume and the proximity of the pan to the windage tray, but everyone seems keen on overfilling K swaps.
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