My hotrod 911sc targa build. 3.0 ITB EFI

[Rivet]

Going back in time to when I did the transmission "refresh" while the engine was out.

My friend Will Pyle from Fairwinds Automotive/Porsche in DE offered to host a 915 trans skill share at his shop. Hanging with him for the day and doing Porsche things was something I couldn't pass over so I made a short trip south.

I have rebuilt quite a few transmissions over the years of differing types, from Ford Model A 3 speeds to full sequential dog boxes but I have never personally had a 915 apart.

After a quick light degreasing of the trans and emptying the oil in preparation to visiting Will I was surprised to see my ROW German market 78 apparently came with a mag case 915 which was interesting.

Also interesting was that it had previously been rebuilt as evidence of a shop's stamping on the case and the general condition of the trans internally. So it really turned into a disassembly, clean (I really need to find a small parts heated spray cabinet!), inspect and reseal thankfully with Will directing and explaining all the components.

Now armed with this knowledge and acquiring the correct tools I do have plans to possibly change up the gear ratios and add a limited slip diff in the future but that will have to wait as I have chassis upgrades as next on my punch list.

[Rivet]

I have really been enjoying the hell out of the car, it is such a joy to drive.

It now has 1.5k miles on it and with the fall season being here I am probably at my happiest.

[montauk]

Originally Posted by rwest

Thanks Mike,

It would be so nice to have the brain close to the engine for shorter wiring etc (you would eliminate a connector). I may get a temperature data logger to see how hot it gets on the side during and after running and in the sun.

I’m still troubleshooting, but will likely get a hold of you for more info.

Best,
Rutager

If you're picking up a new ECU, you can usually opt for a flying lead harness instead of building one from scratch. The ECU-side wires come pre-terminated with connectors, which is what I went with for my Haltech R3. I considered using a bulkhead connector to route everything into the engine bay, but ended up feeding the harness through the same spot where the old O2 sensor bundle used to run. After watching a bunch of Haltech wiring videos, I noticed most builds passed the harness straight through the bulkhead—so I followed suit. I got the harness installed with the engine and transmission out of the car. It would have been a struggle otherwise.

The only wires I had to extend were for the ignition and injectors on the driver's side. Not a big deal.

[rwest]

Originally Posted by montauk

If you're picking up a new ECU, you can usually opt for a flying lead harness instead of building one from scratch. The ECU-side wires come pre-terminated with connectors, which is what I went with for my Haltech R3. I considered using a bulkhead connector to route everything into the engine bay, but ended up feeding the harness through the same spot where the old O2 sensor bundle used to run. After watching a bunch of Haltech wiring videos, I noticed most builds passed the harness straight through the bulkhead—so I followed suit. I got the harness installed with the engine and transmission out of the car. It would have been a struggle otherwise.

The only wires I had to extend were for the ignition and injectors on the driver's side. Not a big deal.

I did do that with my Megasquirt, but can we all agree how sweet it would be not to have to run the wires all the way through, have very short wires and if you needed to remove the engine, you could just unplug from the ECU.

My other issue is I have a Targa and they have a habit of leaking and I worry a little about the ECU under the front seat getting wet.

[montauk]

Originally Posted by rwest

I did do that with my Megasquirt, but can we all agree how sweet it would be not to have to run the wires all the way through, have very short wires and if you needed to remove the engine, you could just unplug from the ECU.

My other issue is I have a Targa and they have a habit of leaking and I worry a little about the ECU under the front seat getting wet.

I’ve also got a Targa, and so far I haven’t had any water issues. The ECU sits where the old O2 Lambda computer used to be, and it’s stayed dry without a problem.

As for dropping the engine, I still don’t think a master plug is necessary. Every wire going into the engine bay can be unplugged somewhere—injectors, spark plugs, cam sensor, oil temp, you name it. Worst case, I snip a few zip ties. That’s about it.

[Rivet]

For mine I spec'd a Maxxecu Race H20 which is water proof and commonly used on personal water craft and offshore boat racing for that reason.

It is mounted under the driver seat and can be submerged.

As for the bulkhead, it is certainly not needed but there are benefits to ease of harness layout and obviously removing the motor.

As an in-between choice you also have the choice to going into the engine bay without a bulk head but splitting the injector harness and ignition harness into sub harnesses with DT connectors (cheap) inside the engine bay to make your life a little easier when removing the engine.

I like doing my best to future proof a harness. As example I have spare I/O inside the cab of the car and also the engine bay. I also have pre-terminated connectors for drive by wire throttle control in the engine bay and near the pedal cluster for the future.

Sent from my SM-F741U using Tapatalk

[montauk]

Originally Posted by Rivet

For mine I spec'd a Maxxecu Race H20 which is water proof and commonly used on personal water craft and offshore boat racing for that reason.

It is mounted under the driver seat and can be submerged.

As for the bulkhead, it is certainly not needed but there are benefits to ease of harness layout and obviously removing the motor. You also have the choice to splitting the injector harness and ignition harness into sub harnesses with DT connectors (cheap) to make your life a little easier when removing the engine.

I like doing my best to future proof a harness. As example I have spare I/O inside the cab of the car and also the engine bay. I also have pre-terminated connectors for drive by wire throttle control in the engine bay and near the pedal cluster for the future.

Sent from my SM-F741U using Tapatalk

That’s a solid point about future-proofing. I’ve already got DBW in the car, but since I don’t know what I might add down the line, I kept all the extra wires in the harness as spares. They’re tucked away in the engine bay. Some folks suggested removing them, but honestly, I don’t see the benefit—adding them later would be a pain. I've already used a few adding oil pressure and oil temperature sensors to the ECU and then using the ECU to drive the stock oil pressure gauge, oil temperature gauge and oil pressure light.

On the topic of injector and ignition harnesses, you're right, I should’ve split them into sub-harnesses. I had to extend the driver’s side anyway, so using DT connectors and dividing the harness left and right would’ve been a smarter move.

[Rivet]

I am not typically a static car show guy as I find them boring but I went out to the Grassroots season closer event in NJ and had a great time.

They had the perfect mix of culture and euro cars and the ride there was spectacular.

Some talented friends took some shots.

[al lkosmal]

Mike,
Nice work......awesome results.

regards,
al

PS: My friend, Tony Otero, (formerly in the PNW, now in New Jersey) mentioned to me that he just met you at a local car show and thought your engine was stellar.

[Rivet]

Originally Posted by al lkosmal

Mike,
Nice work......awesome results.

regards,
al

PS: My friend, Tony Otero, (formerly in the PNW, now in New Jersey) mentioned to me that he just met you at a local car show and thought your engine was stellar.

Hi Al! Had a great time meeting Tony this past weekend. His car is gorgeous.

Thanks for the kind words!

Mike

[mepstein]

Originally Posted by Rivet

Going back in time to when I did the transmission "refresh" while the engine was out.

My friend Will Pyle from Fairwinds Automotive/Porsche in DE offered to host a 915 trans skill share at his shop. Hanging with him for the day and doing Porsche things was something I couldn't pass over so I made a short trip south.

I have rebuilt quite a few transmissions over the years of differing types, from Ford Model A 3 speeds to full sequential dog boxes but I have never personally had a 915 apart.

After a quick light degreasing of the trans and emptying the oil in preparation to visiting Will I was surprised to see my ROW German market 78 apparently came with a mag case 915 which was interesting.

Also interesting was that it had previously been rebuilt as evidence of a shop's stamping on the case and the general condition of the trans internally. So it really turned into a disassembly, clean (I really need to find a small parts heated spray cabinet!), inspect and reseal thankfully with Will directing and explaining all the components.

Now armed with this knowledge and acquiring the correct tools I do have plans to possibly change up the gear ratios and add a limited slip diff in the future but that will have to wait as I have chassis upgrades as next on my punch list.

As I understand it, 78 was a transition year. Started out mag and switched to aluminum. Same internals.

[Rivet]

Just a couple updates.

I attended my last static event for the year at an indoor Euro only evening show being hosted at a friend's detailing shop. They did an exceptional job on getting the venue ready, was a great time.




And since it was there I left it for a few days so they could remove the stone guards that have always bothered me. While I am professionally involved with engines, performance, fab, etc. I know when to delegate.

The repaint (Carmine Red?) the car received sometime in the 90's looks great but looking up close has some spots that you can tell have questionable adhesion now-a-days so I was always hesitant to do anything about it.

When they removed the driver side guard some clear managed to free its self as I thought it would, so a little PPF over that spot and Carrera script will have to do for now. The passenger side came out perfect thankfully. I am primarily a non decal person on all my vehicles, but I have to say I am fond of this setup for now.

Long term I would like to "finish" the car as while I treat it like a running project/mock up, and when I am happy with its performance have it resprayed properly.

This photo was taken earlier this week on a 19 deg F day in NJ which is a great time to confirm some intake air temp, engine temp and cold start compensations




I also mounted some Hoosier DOT tires on my 15" set of Minilites to try out for more spirited drives and it may go well with the new Carrera script.






I have also played with some air filter choices, and had some time to dyno it again to see what the best option was for power. This choice was worth a 12 hp increase over the rain hats with KN filters and within acceptable tolerance to say the it made the same power as bare stacks.




This winter for R&D I will be recycling my Fabspeed RSR headers but converting them to a true V band and fabricating a new collector back exhaust system to try and optimize this current engine configuration. I am hopeful that I will see an improvement and smoothing out of the mid range power delivery with my first version but have three total designs I would like to try (time permitting). I will share photos and dyno results once some theories are confirmed or debunked.

Also I am converting the mechanical linkage to DBW. DBW was always my end goal but I wanted to have dyno data, completed calibration and one season of driving on the mechanical linkage before doing so. One of the many benefits of DBW is you can optimize both HP and torque by controlling intake port velocity with blade angle vs commanded pedal position when using larger intake systems.

[PeteKz]

Rivet, you may already know this, but let me say it anyway: Be very careful using racing rubber in low temperatures. I don't do it (BTDT). I use winter tires from now until March or April.

[montauk]

Good luck with the DBW. I like mine. Two motors or one?

Originally Posted by Rivet

Just a couple updates.

I attended my last static event for the year at an indoor Euro only evening show being hosted at a friend's detailing shop. They did an exceptional job on getting the venue ready, was a great time.




And since it was there I left it for a few days so they could remove the stone guards that have always bothered me. While I am professionally involved with engines, performance, fab, etc. I know when to delegate.

The repaint (Carmine Red?) the car received sometime in the 90's looks great but looking up close has some spots that you can tell have questionable adhesion now-a-days so I was always hesitant to do anything about it.

When they removed the driver side guard some clear managed to free its self as I thought it would, so a little PPF over that spot and Carrera script will have to do for now. The passenger side came out perfect thankfully. I am primarily a non decal person on all my vehicles, but I have to say I am fond of this setup for now.

Long term I would like to "finish" the car as while I treat it like a running project/mock up, and when I am happy with its performance have it resprayed properly.

This photo was taken earlier this week on a 19 deg F day in NJ which is a great time to confirm some intake air temp, engine temp and cold start compensations




I also mounted some Hoosier DOT tires on my 15" set of Minilites to try out for more spirited drives and it may go well with the new Carrera script.






I have also played with some air filter choices, and had some time to dyno it again to see what the best option was for power. This choice was worth a 12 hp increase over the rain hats with KN filters and within acceptable tolerance to say the it made the same power as bare stacks.




This winter for R&D I will be recycling my Fabspeed RSR headers but converting them to a true V band and fabricating a new collector back exhaust system to try and optimize this current engine configuration. I am hopeful that I will see an improvement and smoothing out of the mid range power delivery with my first version but have three total designs I would like to try (time permitting). I will share photos and dyno results once some theories are confirmed or debunked.

Also I am converting the mechanical linkage to DBW. DBW was always my end goal but I wanted to have dyno data, completed calibration and one season of driving on the mechanical linkage before doing so. One of the many benefits of DBW is you can optimize both HP and torque by controlling intake port velocity with blade angle vs commanded pedal position when using larger intake systems.

[75 911s]

Michael,

The build is awesome! Of course I love the hot rod aesthetic you have going with the car and I bet it's even more fun to drive.

I just wanted to give you a huge shout out as well. Michael has shared his time and expertise with me regarding a lot of issues on my current build. He helped design my fuel setup and walked me through multiple issues with my harness and EFI / ECU stuff in general. I'm totally new to EFI and his willingness to reach out to someone across the country and spend time helping me diagnose and solve issues just really speaks to his character.

Thank you! You should make a cross country pilgrimage with the Targa. Would love to see this car in person.

[Rivet]

Rivet, you may already know this, but let me say it anyway: Be very careful using racing rubber in low temperatures. I don't do it (BTDT). I use winter tires from now until March or April.

PeteKz,

40 tread wear tires + north east winter = party time!

I kid, I kid. These are for the warmer months.

Good luck with the DBW. I like mine. Two motors or one?

montauk,

DBW is almost always the way to go, I have even used DBW throttle bodies in mechanically throttle actuated boosted race motors mounted to charge pipes to control intake manifold pressure (boost control) but still keep the turbo impeller RPM high to have quicker power management control. The amount of nerdism available is exciting!

I have the car pre wired for two DBW actuators, but I will be installing one EFI hardware Bosch based actuator as step one, then later two.

Being a dealer for EFI hardware and RHD throttle body kits I am treating my personal car as a rolling test bed and develop both single and dual setups as a solution for my customers that are utilizing RHD itbs and Maxxecu EMS and be able to provide extensively road tested base calibrations for all three options (mechanical, single DBW actuator, and dual DBW actuator).

Michael,

The build is awesome! Of course I love the hot rod aesthetic you have going with the car and I bet it's even more fun to drive.

I just wanted to give you a huge shout out as well. Michael has shared his time and expertise with me regarding a lot of issues on my current build. He helped design my fuel setup and walked me through multiple issues with my harness and EFI / ECU stuff in general. I'm totally new to EFI and his willingness to reach out to someone across the country and spend time helping me diagnose and solve issues just really speaks to his character.

Thank you! You should make a cross country pilgrimage with the Targa. Would love to see this car in person.

75 911s,

Thanks Duane! It has been my pleasure to help. A west coast pilgrimage would be awesome. If you are ever in the NYC area you are always welcome for a visit.

[Rivet]

As a side note... for anyone attending the Performance Racing Industry trade show in Indianapolis you can take a take a look at one of my fun projects on display at the CP Piston/Carrillo booth. It's a nitrous promod drag bike I designed the electronics package for and calibrate in all it's naked, non body worked glory. There was no way we were going to display the bike with its bodywork on and hide all the fun stuff.

The bike uses CP pistons of course, a Maxxecu Race EMS, Maxxecu PDM, M&W CDI, 16v Lithium battery, Plex SDM300 dash, custom IMU, Vance and Hines experimental all billet motor, Vance and Hines throttle slide ITB's (gorgeous), three stages of nitrous, etc.

[Rivet]

Just sharing some development testing on my personal car, I will have a one part number solution ready for e-throttle conversion for RHD itbs very soon.

The kit will include pedal, pedal adapter bracket, EFI Hardware servo (bosch based), connector kits for both, servo mounting adapter bracket that mounts to stock bell crank bracket, linkage arms, heim end and threaded adapter to adjust rod length on a stock CIS rod or a full rod replacement (I haven't decided on that yet).

This video shows the first test after feed forward adjustment and no PID adjustments on the Maxxecu Race EMS. Please excuse the loose throttle return spring hardware and the temp wiring.




And this is the first run test after PID tuning. I currently have the calibration emulating a stock S54 BMW m3 ethrottle strategy for the first test. Throttle body blades shut all the way at idle with an idle bypass valve in use for adjusting air intake at idle. Throttle blade/pedal relationship is at 1:1 for this test. Throttle response is great with perfect pedal vs blade tracking.

A little more R&D time will net me a great base map for this kit, will need some more testing time to see how OEM like I can get the idle to be with a big cam and no idle control valve. So far using the BMW ethrottle ITB idle strategy like presented in the video has it idling at 900 +/- 50 rpm with that DC60 like an OEM car.





Just some buttoning up to do, and then on to making the exhaust sound a little more appropriate to this 3.0 screamer. I am looking forward to the exhaust project and ultimately some more dyno time to find out if I am on the right path.

Happy New Year everyone!

[garment]

Great thread. Sub’d. Happy New Year!

[nospiners]

Definitely gives me the itch to start on a DBW project ..