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Discussion Starter · #1 ·
Hello, I know the topic has been covered comprehensively but I need some advice on putting a Twinspark with ITBs in my recent 64 Sprint GT resto project.

I race a 1750 with a 2.0 Nord conversion on Weber 40’s and love it. However the cab stinks of fuel after driving and I’ve just bought a 64 Sprint GT and would like to put a Twin spark with throttle bodies in for more power and less smell.

I bought a TS engine years ago and see that Alfaholics can rebuild the engine as a 2.3 with a Motec ECU and ITBs but the cost is over £30k !!

I’m not that fussed about increasing the capacity so can anyone give me a ball park figure for just a conversion from the original fuel injection to a system with ITBs, the engine was a runner when I got it but will get it rebuilt and swap the cams etc. I just can’t get my head around the Alfaholics prices. I know their experience of how to build a reliable and powerful unit is factored in and through my own experience I realise cheapest option initially can work out very expensive. But surely the ECU and ITBs can’t be that crazy?

Thanks in advance
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Are you looking to stick with Motronic but add ITBs or run less-expensive standalone EFI?

There are so many ways to go with standalone. I am exploring this for my 912, which benefits from the wide world of VW EFI. For a relatively simple application like a 90's motor you can run a simple system like MicroSquirt or MegaSquirt with batch fired injectors and crank fired distributorless ignition. If you want to step up it would be to sequential ignition requiring a cam position sensor and something like the Tec s200 ECU. I am far from expert on this but Motec is top of the heap and intuitively massive overkill for something like this. If you had twin charging, launch control, water injection, variable cam and intake etc etc perhaps.

The way I'm approaching my project was to sort the two biggest pieces first: throttle body/injectors and ECU. The sensors are the "easy" part, especially on a motor that came from the factory with EFI.
 

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1968 1750 GTV USA Bianco Spino
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Hello, I know the topic has been covered comprehensively but I need some advice on putting a Twinspark with ITBs in my recent 64 Sprint GT resto project.

I race a 1750 with a 2.0 Nord conversion on Weber 40’s and love it. However the cab stinks of fuel after driving and I’ve just bought a 64 Sprint GT and would like to put a Twin spark with throttle bodies in for more power and less smell.

I bought a TS engine years ago and see that Alfaholics can rebuild the engine as a 2.3 with a Motec ECU and ITBs but the cost is over £30k !!

I’m not that fussed about increasing the capacity so can anyone give me a ball park figure for just a conversion from the original fuel injection to a system with ITBs, the engine was a runner when I got it but will get it rebuilt and swap the cams etc. I just can’t get my head around the Alfaholics prices. I know their experience of how to build a reliable and powerful unit is factored in and through my own experience I realise cheapest option initially can work out very expensive. But surely the ECU and ITBs can’t be that crazy?

Thanks in advance View attachment 1711056
Omex which is what alfaholics uses, in as much as i remember, lists a universal ITB with ECU for about 2K with vat.
They also offer coil packs which on first look are the same alfaholics uses.
They don't offer an Alfa specific one (only Ford and euro GM).
Alfaholics prices are for their experience, knowledge and R&D.


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I have been told by some very wise heads you make more HP with carbs than throttle bodies. I am putting on a pair of 45DCOE Webers.
Not my words as I am just an amateur, but these are people who know from extensive work with making HP.

I was happy to hear that as with an O2 sensor and a Zeitronix, I can tune them by road testing relatively inexpensively. I purchased every piece of Weber internals I could from FastRoadCars.co.uk
 

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That video confirms what I've long felt - Motronic is a fantastic injection system and can within reason be tuned in response to the kind of light modifications the OP is posting about. I have daily driven many Motronic vehicles and still do - 911 3.2, E30 325i, currently 964 C4. All of them I've tuned a bit and some of them I've chipped. Today I was swapping rides with a buddy who has worked his 964 harder than I have mine, and with small improvents, a re-flash etc the car is unbelievable, the money was far better spend on those things than going full ITB/standalone. I know some people do go to ITBs and leave Motronic in place... imho worth considering.
 

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1968 1750 GTV USA Bianco Spino
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Alfa did have injected ITB. First with the spica 4 cylinders and then with the Alfa 90 2.0 V6 (busso engine). That used an in house electronic injection called CEM.
 

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I use Jenvey ITBs with DTA ecu. VEMS ecu seems to be a nice one too.
Had a Nord on ITBs (jenvey 45 mm) now a TS (also jenvey but 48mm, on a DTA S80, but a S60 will do just fine, just was able to get a 80 very cheap)
and some other mods.....
 

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1985 Spider (SSM AutoX)
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A few of us have used motorcycle carburetors (which are individual to each cylinder) with a lot of success. Those can be cheaper than the fuel-injected alternative. I think Toyota 4AGE's also came with ITBs from the factory that you may be able to retrofit.
 

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I put in a TS motor into my '67 Sprint GTV last year and due to the size of the original intake plenum, went down the ITB route. After traulling through this forum for hours, I came up with this setup:

Standard intake manifold including injectors = free
2001 GSXR 750 throttle bodies = £80 ( £100 including the hardware to modify)
Speeduino Dropbear ECU = £320
VW COP's = £60
New fuel system Inc pump/swirl pot etc =£200

Unfortunately my TS lump is a bit tired so it's going to be built this winter but I'm planning on using all of the above (maybe swapping the '750 ITB's for Hayabusa ones) and even doing dual stage injection as the ECU is capable of it.

Hope that gives you some ideas at least!
 

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I spent around 2k on converting to EFI.
Emerald ECU. £700
Air temp, throttle pot, water temp, crank sensor. £75
Fuel swirl pot and high pressure pump plus new feed line and return regulator. £125
Wasted spark coil pack. £30
eBay throttle bodies £350
Injectors. £80
Trigger wheel £12 plus machining £ 30
Wire and relays
I also added a zetronix O2 sensor and digital display, the ability to datalog by rpm was very helpful in getting a base map sorted.
Trigger wheel.com and emerald have most of what you need, eBay the rest

Webber's don't make more power how can they? Big mistake is to over size the throttle bodies which looses torque remember 45 Webber's probably have 36 Venturi so a 40 throttle body has more open area, yet everyone goes for 45 TB this slows the air velocity reducing cylinder fill at the bottom of the piston stroke
 

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Discussion Starter · #17 ·
I spent around 2k on converting to EFI.
Emerald ECU. £700
Air temp, throttle pot, water temp, crank sensor. £75
Fuel swirl pot and high pressure pump plus new feed line and return regulator. £125
Wasted spark coil pack. £30
eBay throttle bodies £350
Injectors. £80
Trigger wheel £12 plus machining £ 30
Wire and relays
I also added a zetronix O2 sensor and digital display, the ability to datalog by rpm was very helpful in getting a base map sorted.
Trigger wheel.com and emerald have most of what you need, eBay the rest

Webber's don't make more power how can they? Big mistake is to over size the throttle bodies which looses torque remember 45 Webber's probably have 36 Venturi so a 40 throttle body has more open area, yet everyone goes for 45 TB this slows the air velocity reducing cylinder fill at the bottom of the piston stroke
Thank you, massively helpful and good news👍👍
 

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You can spend more if you go top end but Im not sure you get anything more for the money, you won't make more power than well set up Webber's but cold start and mid range pick up is vastly improved, from my experience I noted a big improvement by adding air horns to lengthen the intake mid range torque was much better, you could also add a map sensor to go from 2D to 3D map but you would need a small canister linked to all 4 intake runners.
If you have good fab skills I have a spica manifold and throttle bodies available but the injector points need machining to fit electric fuel injectors
 

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Discussion Starter · #19 ·
You can spend more if you go top end but Im not sure you get anything more for the money, you won't make more power than well set up Webber's but cold start and mid range pick up is vastly improved, from my experience I noted a big improvement by adding air horns to lengthen the intake mid range torque was much better, you could also add a map sensor to go from 2D to 3D map but you would need a small canister linked to all 4 intake runners.
If you have good fab skills I have a spica manifold and throttle bodies available but the injector points need machining to fit electric fuel injectors
I don’t mind stretching the budget and a 3D map is probably the way I’d go. For convenience (my fab skills are zero!) I’d happily buy the specific manifold that Alfaholics sell for ITBs unless you advised against?
 

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Nothing against AH manifold
What's the reason to throw away the TS single throttle manifold ? Looks, sound or more power? There is not much wrong with it for power just junk the airflow meter and install map sensor I know it does not look as good and won't have the sound of ITB's but it's a good compromise for a street car
 
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