ALFAGTV6.COM

[Duk]

I'm wanting more performance from my 3ltr 75 Potenziata and I'm really undecided as which way to go about it.

My decision is whether to stay NA and port heads, fit decent cams, modify the plenum chamber and make a set of exstractors.

Or go a standard compression (9.5:1) low boost turbo set up.

NA will allow me to keep that sexy Italian V6 note and better go, but a well done turbo will give that broad smooth torque the I get from my other 2 cars (well not the Silvia ATM).

The whole intentions are to do as much of the work myself. I even machined some pipes to make the collectors for a set of extractors before I started to seriously ponder the option of low boost turboing.

I've been doing as much research as I can on porting cylinder heads and even how to build a flow bench.
Camshafts seem to be a touchy subject, but Richard Jameson seems to really know his stuff. If I went cams then I'd be looking at what he offers very closely.

If I went turbo, it is intended to use a smallish 1, probably a late model Nissan or a newish Garrett, which ever 1 I can find on evil pay for the best price that most suits my desired outcome (performance versus $$$).

Any fabrication or porting work will be done by me. The whole idea is decent performance gain per dollar spent, baring in mind that this is a road car, so it needs to be reliable and still offer excellent road manners and return respectable fuel ecconomy when cruising on the highway.

Some people may think I'm beeing some sort of unrealistic dreamer, but I know that excellent performance increases can be achieved when you use your head and can design and make things that are functional and well built.

For the reccord, the issue of engine management is intended to be overcome by using the complete system from the local '86-'88 model Holden Commodore. These are a Nissan system and because they are quite simple and well supported in the aftermarket http://www.nistune.com/, I should be able to have an easilly reprogrammed manufacturer quallity system for minimal dollars. I've also got some experiance with Nissan electrics and there's heaps of stuff on the 'net.

Thoughts and opinions, please.

[MD]

My suggestion to go from Dukone to Dukgone is supercharging. Useful street torque. Minimum changes. Best bang for Duk.

[Duk]

My suggestion to go from Dukone to Dukgone is supercharging. Useful street torque. Minimum changes. Best bang for Duk.

HAHA!!! I like your thinking Mad Dog, but as much as I love Gregs work, a decent supercharger is an expensive option. Much easyer to get a decent turbo in there. A supercharger would provide the best of both worlds tho, both music and motivation

[GTV27]

Provided you can keep your appetite for power in check, a turbo (or supercharger) would have to be the best bet. The proviso is that, unless you are willing (and able$$$) to open up the motor and drop compression, fit better pistons etc... you'll have to run low boost and conservative settings on fuel and ignition to keep it alive (all of which I'm ssure you already know... )

[SydneyJules]

That's the thing with forced induction, isn't it? The temptation to open the taps is too great and the spiral of cash and broken bits starts!

Having seen the silver Alfetta GT go from blown to turbo and get crazier each year, I can't say that I want to do that anymore!

I still think that greg's blower kit is great value, even after exhange rates come into it-
Ease of installation and running, for starters, all you need is the kit and you're off. You can drive the thing around on low boost while you prep for other bits. Don't even need an ECU change or an intercooler to start with. Less hassle, but at more expense.
More engine bay room and less heat. Might not matter in winter, but I was in Lower Light near Adelaide two months ago when some seriously hot days hit, and I wouldn't want to be without A/C in that heat! And the heatsoak through the firewall and transmission tunnel. No thanks!

I think with Greg's blower kit, there's plenty of growth, and the only external change is adding a good FMIC and an ECU and injectors. The rest is in the pulley size. I imagine a 2.5 under reasonable boost would behave like something twice its displacement- just like a big NA donk. Yes please!

Doing most yourself negates a fair bit of cost, and a low boost setup on a small turbo would give great torque, but the growth potential you'll inevitably want will probably lead to: Cutting off old Exh.Manif. flange, and welding new one on for bigger turbo and dump pipe mods, etc etc!!!!!

Be serious with yourself!! You'll want more than you say you will within three months!!!!!

Keep us posted, mate. Those 75 3.0Ps are nice cars!

[Duk]

Turbo boosted performance is such a tempting arrangement

Even with the ease of just "windin' up the boost" on a turbo'd engine, the desire to keep the engine in 1 piece would over ride the desire to chase the exstra horses that may or may not come with the added pressure.
I've actually become quite mechanically (read: financially) sympathetic in my reccent years

Of course a twin turbo arrangement could be on the cards, say Skyline GTR turbos or 2 TD04s from a late '90s WRX.
The issue becomes getting all the air plumbing in there and for some reason, and for the life of me I can't say why, I want to do a single turbo set up even tho a twin set up is more technically correct from an exhaust gas flow perspective

But a nicely modified NA engine has an appeal all it's own, and then there's the music....
That, and the fact that I've never really modified an NA engine and I already have a twincharged Toyota MR2 and a (kinda for sale) turbo'd Nissan Silvia, the variety could be nice

I have the mental path mapped out for either direction, I'm just struggeling to choose which one.

"Einey, meiney, miney moe..........."

[scott.venables]

.... boosted performance is such a tempting arrangement

..........

But a nicely modified NA engine has an appeal all it's own, and then there's the music....

...... and the winner is, a Supercharger!! For a 3L you would probably use an M90 off a Commodore anyway, and these can be had for not too much money. From there, the plumbing is just as easy and you swap making a custom exhaust manifold for making brackets/tensioner mounts etc.

I'm planning to supercharge using an M62, but first I have to find one for the right price.


Scott

[MD]

Hey Jules ! Yuz back in town ! Crickey mate, you're sounding VERY sensible these days. What's going down? Did you ever repair the rear damages?

Mr Duk. stop agonising. If it's not over a hot bird it's a waste of effort.
Go super. You know you want to.

[Duk]

.... boosted performance is such a tempting arrangement

..........

But a nicely modified NA engine has an appeal all it's own, and then there's the music....

...... and the winner is, a Supercharger!! For a 3L you would probably use an M90 off a Commodore anyway, and these can be had for not too much money. From there, the plumbing is just as easy and you swap making a custom exhaust manifold for making brackets/tensioner mounts etc.

I'm planning to supercharge using an M62, but first I have to find one for the right price.


Scott

Scott, I highly reccomend you read Greg's book on supercharging. He says that the best SC for even the 3 ltr is an MP62, better to spin a smaller SC faster than a bigger SC slower.

Plumbing is 1 thing, solid, correctly aligned mounting brackets and crank pulley are a little bit more involved.

[scott.venables]

I guess it's horses for courses as to whether a manifold or some bracketry is easier to make.

You're right, I do need to read Greg's book. The exchange rate has put me off buying it but I'll definitely get it before buying any bits. I had a feeling it could go either way M62 vs M90 for the 3L but Greg's the man.

Scott

[Duk]

Cheers to all who have contributed to my little connundrum.

Despite all of the argument for forced nduction, I have decided to go with my plan for modified NA performance.

This isn't so much a cost decision but more of a challenge, variety and musical decision .

Logic still nags at me and says turbo, and I even started to nut out a sequential twin turbo design for the broadest possible torque curve I figured I could achieve, but the challenge of achieving a nice enthusiastic NA, yet quite well behaved enginge has won.

I would still love to build a sequential twin turbo V6, yes I do believe it's possible to build and at a reasonable price, and maybe 1 day I'll do it just to prove to myself (and others) that it can be done.

So this kinda ends this thread topic, but I'll be starting another very soon.

Incidentally, if there is anybody who wants to do a sequential turbo set up for an engine, look towards the Toyota 2JZGTE engine from the JZA80 model Supra and the (I don't know the Toyota chassis code) Aristo. Much more reliable than the Subaru and Mazda RX7 set up and nowhere nere as complicated as some believe.

[GarthW]

Decisions, decisions, well i'll be more than happy to add my 2cents worth!

Now going by what you've written, i'd say your not after big power, but reasonable performance to say the least, so my first option would be to think about maybe putting in a 24v Quad Cam V6 to replace the 3.0..?
But if your 3.0 is low kms, then why not open her up abit with some porting and cams..? If she needs a rebuild, then drop in some high comp pistons also.

But.... if you can do alot of the fabrication work yourself, why not make up a single turbo manifold and boost it..if low boost only is going to be run, then no need for forged pistons and such. Low boost on a V6 is awesome, coupled with a good ecu...trust me, invest a llittle over a grand to get a good ecu with loom and you wont regret it. If you can do any of the ecu wiring yourself, you will save alot, that i didnt do, and was the most expensive part of the build, alot of labour time having a car converted to an ecu with new sensors, injectors, etc.

Dont be put off by turbocharging, they are just giving the engine more air, ambient heat is easily managed and car behaves like it was standard, except a much deeper idle lol.

Well i hope that was some help, good luck with everything!

[Duk]

But.... if you can do alot of the fabrication work yourself, why not make up a single turbo manifold and boost it..if low boost only is going to be run, then no need for forged pistons and such. Low boost on a V6 is awesome, coupled with a good ecu...trust me, invest a llittle over a grand to get a good ecu with loom and you wont regret it. If you can do any of the ecu wiring yourself, you will save alot, that i didnt do, and was the most expensive part of the build, alot of labour time having a car converted to an ecu with new sensors, injectors, etc.

Dont be put off by turbocharging, they are just giving the engine more air, ambient heat is easily managed and car behaves like it was standard, except a much deeper idle lol.

Hi Garth. Both your and Bazz's single turbo set ups were my original motivation for turbocharging .
Having owned 3 turbo (well, 2 and 1 twin-charged) cars, I'm not put off by them at all. In fact, turbo charging still makes the most sence from a performance/dollar ratio point of view. It still temps me badly, tho. And I'm easily tempted .

My temptation is somewhat tempered by the motivation to both maintain the musical note of a non-turbine muffled exhaust and to have something different from the others that I have here at home (BTW, For sale, 1 Nissan Silvia ).

Having said that, there are some other avenues that I want to persue, not so much in terms of outright performance, but respectable performance with impressive fuel ecconomy (when not driving like a maniac!).
There is also the desire to improve the chassis, suspension and (rear)braking, all without spending much in the way of cash.

I don't know if you spotted my comment about using the 6 cyl VL Commodore (Nissan) computer, but this choice was made because the of the cheepness, the factory quallity and the relative similarities of the 2 engines, so hopefully the factory tune will be farely close. It looks like it will be, going on what I've seen from other peoples tunes in their programable systems .
They are also easily reprogammed (I have some helpful software and some excellent information about the runnings of the factory Nissan system), and with the Nistune realtime 'chip', realtime programable.

Things have been going very slowly on the Alfa lately. The other 2 have taken time, effort and money from me (the MR2 SMASHED the starter motor last week after doing some farely major maintenance. Thankfully it was/is in the shed when it happened). Motivation waxes and wains, but I'm still looking forward to getting stuck into some decent effort put into her .

[kevin]

Duk, my two cents worth : if you are going NA with wild cams then dont use the long ratio box. I have found when I broke my 10:43 box and now using 10 : 41 I have dropped two seconds on the track and a moderately standard 3.0 12v is now giving me a hard time through the slow stuff where you need torque. All I am saying think about your whole conversion with where you want the power and how its going to deliver it. Maybe you already have the 10 : 43 box . Just enquiring.

[GarthW]

Ah ok then, nice to hear Baz and i were motivators!!

Ok, that inj(commo6ecu) sounds good, but, like Phil said, who did my ecu(Bits Of Italy), do it properly and get the best results..basically i was going to go a Microfueller, but 10psi would have been my limit, so i went with the Adaptronic, and cant wipe the smile from my face.

But if cost is the factor, then do what you can, but sometimes spending abit more will save you more in the end...damn i could sell you my ecu cos i want to upgrade to full sequential. Just connect it up and your rocking. Fuel map already written and of course loom would be yours as well. But i wouldnt be ready to do that for another few months, but hey if you can wait, will sell you a cracker, just invest in some high flow injectors, 15psi fuel map will have you flying.

Basically after driving my gtv6 around for nearly 9 yrs N/A, i'll never go back, i'm smitten.