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Discussion Starter #1
I have a 1984 stock gtv6 with the 2.5 engine which i have had now for nearly 4 years which I run throughout the summer (If you can call it a summer here in the UK). It has stock manifolds an ansa mid section and csc back box. The engine runs beautifully and when it reaches 4000rpm the sound is fantastic and it revs through to the limiter if i want it to.
I have however just aquired a 1988 3.0l 75 engine from ebay which I got for an absolute steel
The ad read as follows;

"Alfa 75 3.0 V6 Engine, Bosch L-Jetronic version
For Sale, one Alfa 75, 3.0 V6 Engine, removed from a 1988 car.

Mileage was 122K I recall. I obtained it to use for spares but never got around to stripping it.It was believed to be a good runner prior to removal.

It is complete with all ancillaries, good condition exhaust manifolds, loom etc ( Bosch L Jetronic version). (see Picture)

It must be picked up by buyer from Huntingdon in Cambs, and the auction does not include the "skateboard" it currently sits on.

Any questions can be answered, just email me.

please note: I do not currently have an engine hoist hence buyer must plan accordingly.

£25 start....so get bidding"


I bid late in the evening and bought it for £51.00!!

The question i would like to ask is how much more hp and torque does the 3.0 have and would i be foolish to remove the 2.5 when it runs so well.

I will be laying the gtv up this winter and so could spend time maybe tuning the 3.0l

I also have a spare 164 12v 3.0 engine which has only done 84k would that be a better engine to use.Obviousley the 75(milano) engine would drop straight in with no mods.

so my 2nd questuion is which of the 2 is the "better" engine the 164 or the 75

Thanks to you all in adavnce
 

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Depends on what 75 engine it is, and what you want. IF its stock, power is 188bhp, over the 2.5 160bhp. The torque is much better though, but personaly I dont think the 3.0 is such a gem over the 2.5, despite the extra umphf! cost wise its a no brainer, to make 200hp from the 2.5 is going to cost you 2.5-3 grand. The 164 Qv is I think 200Hp as standard, nice, but more work to fit to the GTV6. A tuned 2.5 is very nice though.!

Its easier to drop the 75 engine straight in, and also easy to get 200 hp from a 3.0 75 engine, with, CSC exhaust manifolds, 164S or QV camshafts, larger intake runners, and Megasquirt or the like ECU. Cost? about a grand maybe, if you install it all yourself. The 3.0 definately benefits from some work on the intake side, since it runs on 2.5 runners and plenum.
 

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Discussion Starter #3
Thanks for your reply The 3.0 has the L jet fuel injection system so would i need to replace the ecu or would the 2.5 one be ok.I have looked at the connector from the 3.0 and it looks identical to the one on my 2.5.I take your point on the intake system would i just replace the intake pipes with larger internal diameters ones and if so which the best way to do it.I have read other posts on intakes and some have had them made and some have just machined the originals I remember when i removed the intake pipes on my 2.5 and gave them a thorough clean and polish the car was much more responsive. I know a lot of you guys dont like the L jet but at the moment i am looking for a simple and eay way to get to 200bhp or so.
 

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erm ecu wise, since your gtv6 is an 84, I think the 3.0 will plug right in (check that though as not 100% sure).

Intake wise you have 2 options.

1) go with the 164 qv style intake and butcher it for the 2.5, or

2) cut out the old runners from the 2.5, and weld in ones with a bigger diameter, but have them flush with the inside bottom of the plenum (the 2.5 runners protrude a long way into the plenum, and IMHO constitute a disturbance and restriction to air flow. also polish off the lip just before the throttle butterfly plate, there is a slight ridge there.

put a good small second oil/air seperator in line with the crankcase breather too, that helps keep the intake cleaner.
 
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It seems like everybody is doing it these days. I do have a question. The GTV-6s that were made for the South African market came with 3.0 correct?

If so, is that the same engine that is in the 164s and 75s and so on? Or was it something else altogether?

I'm going to keep my 2.5 and give it a makeover, with the goal being 200+hp. I've heard some people say they prefer the sound of the 2.5, not that I want to open that can of worms. I do like the idea of sticking with the 2.5 it came with, however.

I can certainly appreciate the reasoning for switching to 3.0, of course.

Good luck with whatever decision you make.

David B.
1986 GTV-6
 

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3.0 South Africa car was an option and yes it's the same as a Milano/75. Your issue with making a 2.5 get 200 hp will be with smog down the road, that is unless your not going to have it as a street car.
 

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making a 200 hp 2.5 is very expensive!!. to make a 200-220hp 2.5 needs

-increase in compression, probably to 10.51, by way of new pistons

-total seal rings

- whilst your in there may as well shot peen and polish stock rods, or go for tks /carrilo rods. sensible to balance whole bottom end. while apart with alloy flywheel, performatek.

- something along the lines of 164s camshafts, fastroad ( more agressive is an option, but then the 2.5 becomes a handfull to drive around town)

- head work. porting polishing, gas flowing.,fully radius valve seats, with bigger valves.new valve springs. custom intake runners

- uprated headers, CSC more than adequate for 200hp

- duel fuel pump, adjustable regulator

- aftermarket exhaust system

- stage 2 injectors. stock injectors will lean out very quickly

- ideally, after market ecu to eliminate afm assembly.

- Transaxle, upgrade to 1.8 TS LSD, lightened 1st.,2nd and 3rd gear. 200+ hp will eat synchros in a standard box in no time at all, hence lightening.

Above mods, along with Alloy flywheel and balanced bottom end, will produce a very responsive fast revving 2.5, to 7000rpm with 210-220 hp.

The same mods on a 3.0 75 engine will produce more like 240-250hp.

SMOG is no probalem at all, since this chap is in the UK. far more relaxed thean say Calif. nice project if you have a spare $5000 us or £2500 GP around.

Above is basically the autodelta engine build instructions for the 2.5 from the 80's. Once the 3.0 came along Autodelta didn't bother with the
 

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But why bother with all this messing around on the 2.5?, when you can hook up a supercharger for half the price, and easily produce 220-235hp with 8-10psi boost and water meth. even more with an intercooled set up. Fuel economy wont suffer, you retain the smootheness of the 2.5, and will get far more torque than you could ever produce with the abobe mods.
 

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Discussion Starter #9
Thank you for all your replies. I will definatley be doing something with the 3.0 engine while it is out of the car but will stick to the 2.5 a little while longer as it is a superb engine with excellent compression (so my 50+ alfa trained mechanic tells me) and a fantastic sound and as i im not desperate to change i will be able to spend more time on the 3.0l so will be ready all your valuable posts for ideas and keep you posted as to what i do.

thanks again
 

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get off the **** computer now and start with the swap immediately! the 3.0 is the motor the car should have had all along. I believe that you can use the 2.5 ecu but get an air/fuel ratio guage (the one's with the led's are probably easier to read than the dial faced guage) as it will run lean at the upper end. also add a larger BMW AFM (5 series?) but start now.

with one of Fred Demateo's ecu's, Greg Gordon's air intake line, shankle cams and S pistons, mine was dyno'ed at 160 HP at the real wheels and absolutely lovely and very usable torque between 3500 - 6000 rpms.

you will not regret this.
 

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If sound is important to you, you might miss your 2.5

I could have upgraded my six to a 3.0 but I chose not to. A Milano can feel a bit heavy for a 2.5 liter but it isn't as noticeable in the lighter GTV6. And I'm so in love with the melody the 2.5 liter makes. I really wish I knew how to make a 3 liter sing the same song!
 

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at least with mine the "secret" was to keep the same exhaust system (a well opened up Ansa) also more cost effective
 

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the 2.5 definately has that "something" over the 3.0, just dont know what it is? 3.0 can be made to sound really nice, put a full stebro or ansa straight through without centre box, and it sounds real nice. not as nice as the 2.5, but just a different nice.

the thing to remember with 2,5, is, you can tune the nuts out of it, 200hp + but you loose the superb smoothness, and what you wont get is the huge torque that the 3.0 has. , however, supercharge the 2.5, and it becomes a fire breathing, torque monster, with that superb noise preserved.
 

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... if you're talking passing CA smog without taking components off the car and back on after, the stock 3.0l is the only choice and it would make a huge difference in the cars performance.

If the 2.5 is perfectly fine I wouldn't even bother - the money is better spent on other parts of the car or things that will need to be taken care of (or a trip to some tropical island :)) When the motor finally has had it - make the switch ... unless money is of no concern. If that's the case then make the swap now!

GV
 

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Discussion Starter #15
well want can i say! thanks for all your input .Been at work most of this week and just got in from the pub and read all your coments In the meantime ive just bought a 3.0 24v super and boy what a flyin machine I previousley mentioned i was laying the gtv6 up for the winter and was lookin for something to run in the meantime and that 24v 3.0 is an absolute peach so i reckon the 3.0 in the gtv is a must.Thanks again and i'll keep you posted about my gtv
 

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Discussion Starter #17
also grant you are right the 3.0 and the 2.5 are definatley a different animal the 3.0 is silky smooth quick and a real steam train of an engine while the 2.5 in a gtv6 seems much more seat of the pants and raw more man/machine a real racer althought the 3.0 is the the more powerfull the gtv6 is still the one that puts a big smile on your face toughchoice
 
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That's a gorgeous GTV-6, Daz. A real keeper.

David B
1986 GTV-6 (black-62k)
1986 Spider Veloce (black-53k)
 

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Daz, your car looks fantastic! I'm in the same dilema. My car has only 76,000 original miles but I'd love a 3.0, power steering and LSD. Maybe I should just buy a car that has been converted and keep this one stock.

Here's mine.
 

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