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What are the specs for your built motor? Any head porting? Can you remind us what turbo you're running and your induction?
It's a GT28RS (I'd put on a more up to date G25-550 or Borg Warner EFR 6528 if I were building it today). Intake manifold is custom CNCed and tig welded, and the fuel rail is likewise custom. Turbo manifold is a basic cast log manifold. Engine management (both spark and fuel) is done with a megasquirt 3. Intercooler is a custom core designed to fit behind the spider front bumper- a GTV would probably demand an air/water intercooler due to packaging constraints. I can't claim credit for the base turbo build- I bought the car from A. Georgi on the forum who is responsible for the getting the turbo running.

Head was a bone stock Bosch 2 Liter (no VVT) with stock cams. For version 2.0, I'm having a head built with 1mm oversized valves, some porting/bowl shaping, and some street performance cams. Turbos don't really need head work to make power, but I'm hoping the head work will outweigh the off-boost power loss from bumping down the compression to 8.5:1 and help with spool. Unfortunately, the head work is the main thing holding up the project. It was supposed to be done at the end of last summer, but my head builder had some health problems and other setbacks. I'm also having the chassis painted while the motor is out.

Bottom end for 2.0 will have JE Pistons (8.5:1 compression), O-ringed Darton liners (sold by Wes Ingram), Carillo H Beam Rods, balanced crank, windage tray, Gordon Raymond oil pump, Alfaholics "Rally" billet flywheel and clutch.

My build thread is here:

https://www.alfabb.com/bb/forums/spider-105-115-series-1966-1994/472713-better-boost-my-turbo-spider-journey.html
 

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Discussion Starter #22
It's a GT28RS (I'd put on a more up to date G25-550 or Borg Warner EFR 6528 if I were building it today). Intake manifold is custom CNCed and tig welded, and the fuel rail is likewise custom. Turbo manifold is a basic cast log manifold. Engine management (both spark and fuel) is done with a megasquirt 3. Intercooler is a custom core designed to fit behind the spider front bumper- a GTV would probably demand an air/water intercooler due to packaging constraints. I can't claim credit for the base turbo build- I bought the car from A. Georgi on the forum who is responsible for the getting the turbo running.

Head was a bone stock Bosch 2 Liter (no VVT) with stock cams. For version 2.0, I'm having a head built with 1mm oversized valves, some porting/bowl shaping, and some street performance cams. Turbos don't really need head work to make power, but I'm hoping the head work will outweigh the off-boost power loss from bumping down the compression to 8.5:1 and help with spool. Unfortunately, the head work is the main thing holding up the project. It was supposed to be done at the end of last summer, but my head builder had some health problems and other setbacks. I'm also having the chassis painted while the motor is out.

Bottom end for 2.0 will have JE Pistons (8.5:1 compression), O-ringed Darton liners (sold by Wes Ingram), Carillo H Beam Rods, balanced crank, windage tray, Gordon Raymond oil pump, Alfaholics "Rally" billet flywheel and clutch.

My build thread is here:

https://www.alfabb.com/bb/forums/spider-105-115-series-1966-1994/472713-better-boost-my-turbo-spider-journey.html
Thanks for the details and the "recipe." Sounds like we have similar goals, so really curious to hear how it runs when it comes together.

Scott
 

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Discussion Starter #23
All -

My deal on a 2.0 Twin Spark fell through, but I do have a spare Nord 2L block and crank in the garage.

Torn between sourcing a TS head on a Nord, using a Nord head on a TS, or sourcing a complete TS engine.

Here's what I'm thinking as far as plusses and minuses:


TS head on a Nord block:

-Nord block is said to be weaker (would use aftermarket liners)

-Requires machine work to head because of shorter head studs on Nord. Few other fitment issues.

-Custom intake and exhaust manifolds available for turbo

-Visual appeal of TS head

-I already have block and crank


Nord Block and Head:

-Head doesn't flow as well (not as much of a problem with a turbo build)

-Have to source or fab intake and exhaust

-Block not as strong (aftermarket liners will mitigate this)

-No real fitment issues.

-I already have block and crank


TS Head and Block

-Better flowing head

-Visual appeal

-Intake/exhaust manifolds available

-Sourcing one in the U.S. would be somewhat difficult; sourcing one from overseas would be difficult and have the added expense and headaches of international shipping.


Thoughts?

Thanks,

Scott
 

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Discussion Starter #24
Ok, have had some discussions with an Alfa guru, and the Nord option is looking like it's more feasible. Apparently, the intakes interchange between a TS and a Nord, so the Extreme Tuning piece would work. And 1.8 turbo exhaust manifolds can still be found, so that would take care of the exhaust.

More to follow...
 

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For some reason, I thought the 1.8 exhaust manifolds were different, but it’s fairly likely it could be modified to fit under worst case scenario.

If you order, let us know how those manifolds work out. Bulgaria isn’t exactly a traditional location to find Alfa parts, but they do at least look nice and are priced as relatively premium products.
 

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Reading most of the above, makes me think you are trying to re-invent the wheel. The I.8T engine (not offered in the US market) is a tried and 'simple' solution for everyone wanting a turbo 4cyl old Alfa. We routinely make 250-300 crank hp. In std form, they had 155-165hp and with a simple chip change they went to 210hp (known as GpN spec). What this does is raise boost from std 0.65bar (9.5psi) to ~1.1bar (16psi) and 'desensitize' the knock sensor a bit. Of course, this is never enough, so we go even further. IF you know what you are doing, you can go to ~300hp reliably, without changing any internal parts, a definite tribute to the strength of this engine! For peace of mind and frequent trackday use, I do advise forged pistons, and that's about it, as std turbo rods are very strong -they may look exactly the same with 2liter rods but trust me, they are not. As for the turbo itself, the std Garrett T3 is Jurassic, so best solution now is a GTX2860 or G25-550. The first mandatory step for reliability is a good head gasket. We so far have an excellent record and zero failures with the Italian NAVA gaskets with separate O-rings. These have a square x-section and 3 shallow ridges topside which bite into the head. No worries up to ~2.5bar (36psi) where std 1.8T liners start to break. I've run up to 2bar in my engine (std pistons) no problem, although its set for a steady 1.7bar(25psi). With the old GT2871 turbo, I had 276hp @5150rpm and 400Nm (290ftlbs) @4380rpm. I have since upgraded to a GTX2860 and the car is a LOT faster -haven't gone to the rollers yet. Whatever you do, one of the first things to install is a good AFR gauge. The above was all about the 1.8T. A used 1.8T in Europe goes from 700-1200€ complete.
Now the 2liter... in few words its not suitable for turbo use unless you spend a LOT more, compared to the 1.8T. As proof, ask a simple question: in Europe where both engines are available (although the 1.8T is getting a bit rare) why do people prefer to play with the 1.8T instead of the 2liter?
In 1990, factory 1.8T racers had evolved to 430hp/490ftlbs (no mistake here) at 2.3bar(33psi), all under 6400rpm. Private owners have nowadays gone to 350-400hp, but my personal opinion is that up to 300hp you can have lots of fun with everyday reliability without having to fix ***** all the time. I will not go as far as to say such a car is as reliable as a na engine. Be prepared for increased preventive maintenance and checks, for example resurfacing the exhaust manifold 1-2 times yearly and replacing the fuel pump every 3-4 years or so, more frequent injector cleaning etc. For anyone interested, here's a list of what my engine cost to build (in €). Note that all this concerns the Alfa 75 and is not necessary if you don't push the car around a lot or. I have two such cars, both red and original 1987 1.8T models, one with the below mods and the other modified to 3.2liter 24v.
One last note regarding the IC (intercooler). Since I perfected the water/air system, performance is amazing, to the point that I reduced boost to 1.5bar(21psi). This all became possible by drastically reducing the intake manifold air temperature, after a lot of 'research' and under-hood measurements resulting in simple mods to the way air enters the engine.
In the 105 chassis.... you are very limited in space. Yes, I have a friend who shoehorned (proper word) a 1.8T inside his 105 2-door coupe after a lot of cutting and fitting. Actually, it wasn't a 1.8T engine per se, but a rare 2liter Turbodelta engine with all the 1.8T stuff around it. Lots of work to put it in there, especially around the exhaust manifold, alternator and steering box. With a stock ~175hp, he ended up breaking several rear ends and gearboxes in stoplight drags -torque breaks things, not power. Sure it was fast but every other month he had it on the hoist fixing/replacing something. When he finally ripped the motor out, he found peace...
Alfa 75 1.8T cost
Good Used 1.8T engine complete with wiring………1000€
105480320001 Intake cam............…………………………70
Aeromotive Adj. fuel pressure regulator..……………..200
Fuel pressure gauge………………………………………….……..20
MSD 6AL-2 Programmable ignition………………….…….400
3bar MAP sensor………………………………………………..…….90
4xChampion N2C plugs……………………………………..…….12
Large airflow meter (BMW535), std 1.8T pcb.………150
Bosch 5bar (75psi) fuel pump 0580464126….………130
0280150400 injectors………………………………...………..200
AEM failsafe gauge.…………………………………….………….300
GTX2860 turbo.…………………………………………….………1000
Nava O-ring head gasket..………………………………………250
Blow-off valve………………………………………………….………..80
63mm exhaust pipe, 2 mufflers……………………...…….600
Large water radiator, two fans……………………....…….300
78⁰C thermostat..……………………………………….…………….50
Large FMIC, relocated TB with suitable manifold/associated piping…….400*
Crank scraper/baffle…………………………………….………….250
Head rebuild………………………………………………….…………200
Alfa 75 Evo exhaust manifold………………………....…….400
Machine shop work…………………………………….…………..500
Silicone hoses, bearings, seals…………………….………..200
Turbine Ceramic coating…………………………....………….500
*OR:
W/A modified std I/C, front radiator for I/C and electric water pump……400
Options: std pistons/liners or CPS pistons + new liners…………..………~1000
TOTAL PARTS COST ~7900€ …WITHOUT LABOR!
~270-300hp @ 1.7bar boost

Jim K.
 

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Discussion Starter #29
Jim -

Thanks for the detailed response! A few comments/questions -

-I'm ok with the cost.

-I'm concerned with availability of a complete 1.8T engine. Would you happen to know where I might be able to find one?

-300 hp would be great.

-I really want to keep any cutting to a minimum; perhaps fabricated exhaust plumbing would help.

Thanks again,

Scott
 

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I think for European folks the 1.8 is a clear winner. I ended up going with a standard Nord because it was looking like $2k to get a 1.8 motor shipped from Europe, and I’d be taking the risk of damage or getting a bad core. Then I’d also have to deal with sourcing other internal components like forged pistons from across the pond. Since 2 liter cores are practically free here, you can buy stronger liners and forged internals for the difference.

I think you could make a 2 liter at least as strong as a 1.8 with a good deck plate and better liners. I just wish there was an off the shelf option. Driving a Subaru STI makes me a little jealous comparing what’s available for the two motors.
 

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I don't recall any chassis cutting is necessary, but a dedicated exhaust manifold was built as well as special cooling ducting for the alternator (as it is situated right next to the exhaust manifold). On the intake side, some shortening of the intercooler branches was also done. I saw the car ~12 years ago so its not a clear picture any more. The owner, after pulling the engine out, sold me the engine harness and Cosworth (Marelli L6) ecu along with all sensors. I bought the stuff as spares for my own build but I didn't end up going the same way.

Jim K.
 
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