Help me style this beat-up old 912

[MichiganMike]

Enjoy the dyno pull!
https://youtu.be/J_VG71Puj70

Final numbers: 295HP with 265ft.lbs torque:

[MichiganMike]

[Ferrino]

Mamma Mia! Amazing! Will you/it be at the Luftgekuhlt event this weekend?

[MichiganMike]

I'm thinking of going to Festival of Speed on Saturday and Luftgekuhlt on Sunday. Will I be allowed at Luftgekuhlt, being that it is German for "Air-Cooled"?! Maybe I'll just have to keep my ducktail closed at the event...

[Flieger]

I think you'll need to park in the spectator parking which will be filled with plenty of water cooled Porsches I am sure.

[Fixer]

Wow great numbers Mike ! Those Subi flat 4s are terrific engines.

[MichiganMike]

Update to the build!

A few great things have happened since bringing the car down to SoCal. I have been privileged to make it out to many great car shows with the R-STi, including Luftgekuhlt and the Farewell to the 6th St Bridge. Since these shows, I have finally gotten my seats made and installed. The belt mount points have also been relocated to pinch more on the waist line and not the abdomen. They now pull down on the waist and not backwards towards the rear of the car on the stock mount points. Also, I have removed my good for nothing CD Deck, and replaced it with a delete plate. The plan is to use a Bluetooth stereo in the car for when i want tunes. This will keep my weight down and still have some Jams when driving! I plan to mount the Heuer stopwatches I got recently on the plate as well. If I get fancy enough, I made add an LED on them to shine them up at night:

[MichiganMike]

Got my Heuer clocks installed and they came out pretty nice. Lighter than my dated CD deck for sure!

[nein14]

Who did your seats are they aftermarket or original Recaro's

[MichiganMike]

Hi Nein914 - Seats are aftermarket made by TRE Motorsports in Van Nuys, CA. These are the RS Style seats from them, as their RSR seats have higher upper bolsters. I found these to be more comfortable and intended for longer drives. Here are the two side by side (RSR vs RS)

[Tremelune]

Somewhat random question: Did you come across any viable transmission swaps while researching the Subaru route? I've read a lot about LS swaps, and I always come back to the limitations of the 915.

[Andy Somogyi]

Just read about this build, fantastic work!

Did you guys have any issues with cooling? Does the Datsun radiator sectioned in three provide enough cooling, even with the outer radiators tucked in the fender wells?

[ej911]

What a fantastic build. I would be considered a purist, but this thing is perfectly fine for me. The final product is amazing. Now I want to build one..... Looking for 912!

[Tremelune]

Indeed, I'm curious to see how this car is doing. Now that I'm often driving about 7,000 feet, the fantasy of a turbocharged STi motor grows increasingly interesting...

[MichiganMat]

Hey everybody,

Yeah, the car is doing great. Its daily-driven around SoCal these days and sees the occasional auto-x too. The cooling system is /right on the edge/ of being sufficient and was really pretty complicated to make. We started out with just the fender coolers (with a fan on each) and it really wasn't enough to keep the car cool, so putting the center section was a bit of a "hail mary". Luckily it worked and we haven't seen high temps since. My brother is working on getting the car out to a track day at Willow Springs soon and then we'll *really* know if we did a decent job with the cooling system.

Otherwise though, the car has been flawless: get in, fires right up, and purrs like a kitten all over town until the turbo kicks in and rips your head off. The 912 is such a comfortable car to drive, a real sweetheart, and a huge departure from my NA 3.0L 911S... the STi motor is so much more nimble, lightweight and smooth, where my S is binary, static, accelerating and decelerating all that NA rotating mass.

We're a bit limited in performance by the shorter wheelbase and small tires, but my brother has been learning to hustle it around the AX courses. He's working to get a limited slip put in soon so that all that STi power makes its way into the speedo and not converted into tire smoke.

You can follow Mike and the car on Instagram here: https://www.instagram.com/912rsti/

Thanks for asking about it, and holler at us if you have another questions!

- m

[Andy Somogyi]

Thanks for the info about the radiators.

I've just bought a 912e, and I'm getting ready to *probably* swap in a DOHC N/A EJ25. I worked out that the Subaru swap will cost literally half of what it would cost to build a *reliable* type4 turbo engine to 200 HP, and the Subaru is just about 200 HP out of the box. Plus, it's lighter (even with the coolant) and about an order of magnitude more reliable than a built type 4.

In my case, I really want to have the car looking 100% original, so I think I'm going to build a custom fiberglass front valence, molded off the original valence, but with three ducts (one for each radiator), similar to the RUF style.

I've found this 911 who uses a really similar radiator setup to yours (I stole these off another Pelican Parts thread) He's running 400 HP M97 3.8 liter engine out back, and evidently, these seem to cool it OK.

Thanks for the AWESOME build info, you're an inspiration man.

[Tremelune]

Whoa, where's that thread?? I haven't seen anyone put a water-cooled motor in an air-cooled 911.

If I had a 912 that needed motor work, the Porsche lump would get pulled so fast...

[Andy Somogyi]

Originally Posted by Tremelune

Whoa, where's that thread?? I haven't seen anyone put a water-cooled motor in an air-cooled 911.

If I had a 912 that needed motor work, the Porsche lump would get pulled so fast...

Here's that build thread with the 911:

http://forums.pelicanparts.com/porsche-911-technical-forum/518231-pvx-build-thread-one-view-slope.html

Interesting that his 911 is also running radiators in series, possibly because it's simpler to plumb. I've worked out the math, and parallel radiators are more efficient, likely why new Porsches all run their multiple radiators in parallel.

The challenge with parallel radiators is ensuring even coolant flow, and there's a possibility of stagnant coolant locations (where the coolant just sits, does not flow, hence does not cool).

The challenge with serial is ensuring the pressure drop is not too high. Think about, what happens if you put your hand in front of a hair dryer? It stops blowing air, the fan will just spin. Your water pump is just like this, it's designed to operate with a minimal pressure drop, it will pump a large amount of fluid if there is not a lot of pressure difference. As you start increasing the pressure drop, the efficiency and hence the amount of fluid it pumps rapidly drops.

In summary, regarding the serial/parallel radiator discussion:

Radiators in series:

• easier NOT to screw up (you're guaranteed to have the same amount of coolant through each radiator).
• easier to plumb
• produces a higher pressure drop -- this means that the water pump is working against a higher pressure load, which means that loses efficiency if the pressure drop is too high, the pump will not work at all. need to be really careful here.

Radiators in parallel:

• higher efficiency and cooling capacity than series
• there's a reason why all factory multiple-radiator cars run them in parallel
• easier to screw up -- if the flow is not balanced, parallel is much worse than serial.
• more complicated plumbing, somewhat heavier because of extra plumbing.
• lower pressure drop -- the water pump will operate in the range it was designed to.

[chrisbalich]

what a fantastic thread.
really helps motivate me to get to work on my own long-term project.

well done!

[Tremelune]

I would stick with serial...It's a tried-and-true setup for the vast majority of 911s that are running extra coolers. I think it's also probably moot, considering a center-mounted cooler will get waaay more airflow than a fender cooler. I suspect that would render the difference negligible...and a good fan might solve a lot of problems anyway. Running tubes places where they were never expected...Regulating even pressure/flow between two paths...Maybe stressing the oil pump more (?)...I dunno. I think you've nailed the pros and cons, and my choice would be clear.

When my 250-300hp motor (3.6 out of a 993) had a center cooler, it never even hinted at exceeding 210°F. Now that it only has one fender cooler (with a nasty fan), I've only seen it go as high as 230°F on a warm sunny day going up a mountain. I think two fender coolers with monster fans would be more than adequate for a Subaru motor (pure conjecture...).

One thing is clear to me: a 912 with a stock look and an STi motor would be sweet. I've often fantasized about putting a Subaru transmission in as well...