308 Weber to TWM throttle body and electromotive

I have been with this project since October of last year. My car is a 1978 Euro spec 308 GTS with a custom dual exhaust and borgo hi comp pistons. My goal is to incorporate the twm throttle bodies with the least amount of modifications to the car and existing parts. I attacked this project in 2 stages. First stage was to install the electromotive TEC GT ECU, coil packs and trigger assembly, (program the ECU with basic parameters) fire up the car, then proceed to yank all the carbs, intake manifolds and fuel pump. Install all the sensors. Luckily I know of a good machinist, because we had to modify a lot of existing parts and fabricate new ones. Stage 1 is complete – fired up the car around Christmas without any issues. I was able to reuse all the throttle linkage on the webers for use on the throttle bodies – it took some effort – but it is silky smooth. So far, I have at least 120 hours in the project, I estimate at least another 50.

Parts that needed to be procured:
Electromotive Tec GT ECU, Direct fire coil packs, Wiring and Power Harness - $2500
Custom Terminal blocks (power and ground), wiring, connectors, etc. - $200
8 Custom spark plug wires - $200
8 new spark plugs – NGK BP5ES - $25
4 TWM throttle Bodies with custom fuel rails - $2400
8 RC 270 Injectors, about 26 lbs/hr. - $800
8 custom FI connectors - $100
Mallory 60 FI Fuel pump - $200
Hi pressure Fuel line and all the cool anodized aluminum fittings, - $300
Custom Fuel filter - $50
Fuel pressure regulator and fuel pressure gauge. - $150
Fasteners (intake manifold, throttle body top, new bolts for throttle body to manifold, and many many many others). - $200
Intake Manifold gaskets - $75.
TB base gaskets were hand made, TB to air cleaner gaskets (hand made).
IAC pump Motor and pump housing - $250
Push lock brass fasteners and tubing for IAC distribution - $150
Metripak and Weather Pak connectors for all the sensors, and the crimper - $200

Sensors that were bought and installed:
Trigger sensor for the direct fire coil packs - $100
4 wire heated O2 sensor - $120
Coolant temp sensor - $50
Incomming air temp sensor - $50
MAP sensor - $100
Throttle position Sensor - $125

Parts that needed to be modified: - $550
Intake manifolds needed to be bored on one side to accommodate the injector stream.
Plastic base spacers below throttle bodies were tapered from 42mm down to 40 mm and were bored with a notch like the intake manifolds to accommodate injector stream.
A lip needed to be carved out of the top of throttle bodies to accommodate stock velocity stacks.
Drill hole in exhaust, weld in bung to mount O2 sensor.
Drill out crossover tube between intake manifolds to accommodate new coolant temp sensor, weld in new bung – right beside old coolant sensor – need two now.
Drill and tap holes in intake manifolds to accommodate Air injection for IAC.
Drill out all 4 velocity stack mounting holes for bigger studs.
Drill out all 16 stud collars that go inbetween throttle bodies and air box.
Resurface intake manifolds that were pitted and corroded on gasket side.

Fabricated Parts:
4 (1/8” thick) plates for the top of throttle bodies for use with stock airbox to cover opening left over from carb main jet air draw (the throttle bodies do not have this passageway). - $50
IAC distribution manifold to 8 cylinders. - $50
IAC mounting bracket. - $40
Mounting bracket for trigger sensor - $100
Custom heat shield for DFUs (direct fire coil units) - $25

Issues to date :
1.) What to do with intake manifold gaskets – do I leave them alone, or cut them to match the coolant passageway in the heads, as the original gaskets swelled and filled up the passageway. I think I am going to cut them to match the whole passageway..
Image Unavailable, Please Login
Image Unavailable, Please Login
Image Unavailable, Please Login
Image Unavailable, Please Login
Image Unavailable, Please Login
Image Unavailable, Please Login
Image Unavailable, Please Login
Image Unavailable, Please Login
Image Unavailable, Please Login
Image Unavailable, Please Login

 

Mallory 60FI pump installation, complete with air bleed and return
Image Unavailable, Please Login

 

Hmmmm...I think I have a case of "throttle body envy"...

I looked into the TWM TB's myself some time ago --- but couldn't get my mitts on a set of intake manifolds anywhere (sadly, my car is an injected version).

Are those stock (308 carb) manifolds, or does TWM produce them as well???

 

Stock 308 carby intake manifolds - slightly modified for injector stream. And all stock linkage too!!

 

Good stuff Giovanni! Pictures and progress.... that's what we wanna see

PS. for some reason I thought your car had CIS. Now I realize it's carbs.

 

Is it an optical illusion in the picture or is the botto of the fuel pump and the fitting sitting below the bottom of the chassis...which wouldn't be good over bumps?

Everything else I see in the pictures looks GREAT! Nice job.

 

Great thread.
I've been wondering what it would take to change my 308i to these throttlebodies.
Just last night i was looking at the TWM site and seaching E-bay if there were any carb manifolds for sale.

 

Giovanni,

Great project!

Please, more photos of the progress.

 

terrific!
I've always been very interested in these in a 'real' application.
This is going to be great fun!

 

Giovanni,

Do you know what the difference is between the Electromotive Tec GT and the Tec3?

Also, I wanted to mention the O2 sensor location. If I'm not mistaken it should be located between the 9 o'clock and 3 o'clock positions. It looks like yours is at the 6 o'clock position (straight down). I think it has to do with condensation settling at the bottom of the exhaust pipe. It may affect the o2 sensor function and/or end up rusting it in place. Just something to be aware of.

Are you installing one or two oxygen sensors? If it is just one it would be better to mount it at some point before the muffler where the gases from both banks of cylinders are combined. Otherwise you'll be reading the air/fuel ratio of just the forward bank. I'm not familiar with the exhaust system on your car so maybe it's not even possible.

 

Hi Erich, the tecgt and tec3 are just about identical, except the tec3 supports sequential fuel injection in which you need a cam sensor. You are right about the O2 sensor orientation, but that was the best place we could find for it, and it is mounted before the muffler and i have a true dual exhaust, so no matter where i put it, it will read only one bank - which is totally sufficient in my case since the throttle bodies and computer are very precise and technically should see no difference between banks - unlike carbs. This has been a great project. mo pics to follow shortly.

 

Was there a big price difference between the TecGT and Tec3? Is the TecGT still in production or is it an older model?

The Ansa test pipe I installed (replacing the single cat.) has a bung for an O2 sensor and thermocouple. Of course I'm happy about that

Thanks, Erich

 

Mark, you are correct about the fuel pump hanging too low. I am going to replace the stock fuel filter with an inline divece, thus giving me more room to get that pump moved over and up.

 

Time to regroup here a bit. Thanks for all the responses – either here or personal.
Here are some updates from the original post.

Gotta move the fuel pump up – no brainer.

1. Also need to plumb the return line from the fuel pressure regulator back in to the top of fuel tank 2, and not into the input of the fuel pump, although tthis will work as it is, but I will get hot aerated fuel into the pump. I still need to tee the bleed screw on the bottom of the new pump to the return line tho.

2. Intake manifold gasket is genuine Ferrari issue, and I will NOT drill holes in it or cut it out to match the water passageway – not enough supporting data or results set to determine if this is a viable solution for the gasket pulling away into the water channel.

3. I need to change the configuration of the front bank of throttle bodies so the injectors are inboard – both fuel rails should down the middle of the two TBs. In the current configuration, the injector stream will be hitting the manifold wall instead of the back of the valve as it does correctly on the rear bank of TBs (thank you Dave H. for that catch – you rock!). This involves trying to fit the linkage completely different from what I had intended. So I ordered all new levers (4) from TWM – About $150. And am going to use Heim joints and rods as the connecting linkage between the levers. Need to carve out the same notch for the injector stream on the other side of the intake manifold for the front bank also – sheesh.

4. Also had top plates fabricated for all the throttle bodies that will cover up the gaps left with fitting the original air box – (the cutouts that expose the choke and main jet circuitry)
Image Unavailable, Please Login

 

shiny go fast parts!!!
Image Unavailable, Please Login

 

IAC distribution manifold
Image Unavailable, Please Login

 

MAT (outside air temp) sensor mounted in inlet duct
Image Unavailable, Please Login

 

new coolant sensor - alongside the old coolant sensor - one is for the tecgt and the other is for the instrument cluster in the 308
Image Unavailable, Please Login

 

Throttle body work - tapped holes for IAC fitting. note taper in intake manifild cut for injector stream - these are the manifilds that need to be reworked, and have the taper cut on the opposite side for proper direction of injector stream to back of valve - instead of manifold wall.
Image Unavailable, Please Login

 

Everything looks great!

In the upper right of the picture is the IAC. It looks like the GM part and is a needle valve operated by a stepper motor. Ptu your mind at easy, it'll be fine.

 

Gotcha Mark - thanks, in the off position, the stepper motor valving closes off the port to the bases of the manifolds, while the port to incomming filtered air is open - but thats OK. In the pic with the throttle bodies strewn about the bench, in the upper part of the pic, those throttle bodies have the drilled hole for IAC right next to the cutout for the injector spray - i dont know if that will be a problem or not, but i really dont have a choice as to where i can put those holes.

 

Where are you pulling the MAP vacuum signal from? I like what your doing, and I've done ITB conversions with Electromotive TEC products.

 

Giovanni,

I see that you selected 26lbs/hr injectors. Utilizing the Electromotive Wizard, that would indicate that you are expecting to get about 350+ brake HP. Is that correct? This caught my eye in that I have EFI in my QV and am running 19lbs injectors with 45lbs fuel pressure. I should note here that I am running stock pistons. I recall talking to someone in the past who had 22lbs injectors and ended up washing out his cylinders. Maybe something to look into?

I also ran the calculations through the RC website configurator and came up with basically the same numbers.

 

I am pulling MAP vacuum off the brake booster line which gets vacuum from under the throttle plates. Interesting about the injectors, they are the ones that came with the TBs. I Know they are a bit on the strong side, but i didnt think i would wash my cylinders out. I have hi comp borgo pistons, but am no where near 350 HP, expecially at altitude. If this is really a problem, i can swap them out - they are not cheap tho. Will altering the duty cycle from the tec gt fix the problem??? Great input guys, I need all the help i can get as I am pretty much winging it......

 

It should be fine, there is no reason in the world I can think of that would cause you a problem.