Light Weight Normally Aspirated Or Heavy Weight Force Fed???

[Duk]

Come on, you don't need air-con or power-steering, is this car for driving in the hills or for commuting?  That's what the F6 is for right?  I took the PS off my 90 track car, and it had a 320mm steering wheel, on wide slicks; definitely a pain in the arse to park, but how often do you do that?  Made no difference to driving over 10km/h.  Okay, maybe 30...

Don't forget, if you were to force-feed her, you'd probably need a bigger radiator as well, adding weight to the worst possible place.

I know what you mean, grunt can certainly be addictive, but I'd go for handling with just enough horsepower, over an overpowered car every time.  Grunt is good in short bursts, but handling is forever.

Yeah, I've often thought myself about how a 4 litre would have been, with a TA that could cope with it.  The 3.0, and even the 2.5, was considered a 'big' engine in the 90 and 75 in period, but times have certainly changed.  I look with envy at every Mercedes C63 I see.

The TA cars are really well balanced, and reasonably light, so I always figured I'd enhance those characteristics, rather than trying to make them into something they're never going to be.

Something that I've occasionally thought about to help the handling, but wouldn't have the skills to do myself, is to lower the engine in the frame.  Don't even know if it would be possible, but you clearly have some skills and knowledge.  Trouble with that is that it would have to be dry-sumped in all likelihood.  That, and get the biggest tyre footprint you can.

Again, just my opinions, I know FA.

Lowering the engine and moving it back are well worth considering. Doing it for a decent price is the challenge.
Maximising tyre footprint is on the cards with some extra mods.

[Trikes]

Me being a Family man I opted with my last car a Proton Satria GTi and now with an Alfasud I opted for light weight and handling. Not had the Sud for all that long but it was already used for Targa's and Hill Climbs so it was no brainer to purchase it when a Roo took out the Satria last December. I removed over 130kg from the Satria and improved the Exhaust along with fitting a 1.4kg Flywheel plus a lot of other stuff. But the GTi handles like 'corner what corner'. Before purchasing the Sud I did the last 6 stages of Targa Tasmania 2016 and was very impressed with what it did to higher powered cars like Porsches, Evo's, Wrx's and a Nissan GTR. Admittedly the 1600 Sud puts out 145hp at the wheels so it's no slouch but it was in the corners where we made up our ground on the other cars plus the driver wasn't scared to cut the corners and drive on the grass to shorten the track or Stage. Suspension was just worn Koni's with front Alf Struts. The GTi had C/O's etc etc with an internally stock engine and netted me 3rd in Class B the first year and 2nd last year in Class B (State Hill Climb Series in Tassie. It was always around the top ten outright or just outside it. So in my opinion one doesn't always need tons of power but the guy in the Honda that always won Class B has a stack of money in the engine and computer. I wanted a car that's well balanced and easy to drive on the limit. I admit there is a litle sorting and up grading with the Sud but even thou the Sud has won lots of Class races and quite a few times outright. The Proton was tons of fun and predictable on the limit and I left the AC connected and used it to clear the glass plus it was a bonus on hot days.

[Duk]

Some nice input Trikes.
Getting the 75's weight down and improving the location of key parts is high on the 'want' list.

But as I've mentioned, having some stout grunt without having to rev the crap out of the thing to achieve decent performance is also high on the 'want' list.
If I could mount the Vortech to the clutch housing and drive it off the tailshaft...................... 

[oz3litre]

I'm with Duk on the carbs reliability question. I spent 30 years or more playing with carby engines in VWs, Alfa 33s and others and wouldn't go back to them after getting used to EFI. Carbs suffer from worn linkages, accelerator pump wear, blocked jets, leaking gaskets and not staying in tune to name a few things. I was always having to fiddle with mine. They rarely run completely smoothly, unless brand new and tuned perfectly and even then, not for long. Even at 20 plus years old the old L-jet is very reliable and smooth. The Motronic system is even better. Both benefit from reconditioned injectors after many years of trouble free operation. Once you understand EFI, it is easy to maintain and you very rarely have to touch a thing. If anything does play up, it will most likely be an easily replaced sensor.

We have two L-Jet 3 litre 75s at present, along with my 2004 GT with the glorious 3.2 Busso and my wife's 159 2.4 JTDM ti wagon and we love them all. I also owned two Potenziatas previously and two 164s. My preference is for putting a 3.2 in the 75 one day. My GT has bags of power with that typical Busso flat torque curve, revs easily to 7,000 rpm and is incredibly flexible. It will start off in 2nd without blinking and even in 3rd if you ride the clutch a bit and as a result is a joy to drive in any conditions. I always thought the old 3 litre 12 valves were flexible, but the 3.2 is more so. It will drive around like an auto with your foot off the throttle easily. Mine has a cat-back exhaust system and sounds absolutely awesome. The 2.4 diesel is a lot of fun to drive too. It has 400nm of torque and 210 bhp, gets off the line very quickly and flattens hills like they aren't there. I have no problem with the reliability of turbos on an engine designed from scratch with them and like the power they give, but they are way outside my budget, skill and patience to fit to a non-turbo engine like the old Busso 12 valve.

[Duk]

Something that carby owner/flag wavers always seem to be completely ignorant of is the fact that a carby, or mechanical injection for that matter, simply can't be accurate over the hugely varying operating conditions a road car engine is expected to operate in.

Plus there is the problem of how carbies actually work, especially when idling.
When tiny amounts of fuel are expected to be drawn out of the carby and into a small amount of slow moving air and maybe having to cover a reasonable distance, fuel falling out of what little air movement there is, is very real.
The notion of carbies being accurate and efficient is purely rediculous.
Yes, if sized and tuned correctly a carby(ies) more can deliver the correct amount of fuel and present no significant flow restriction when the engine is operating at peak power. In the same way that a mechanical advance distributor can also provide the correct ignition timing that the engine needs at peak power (or peak torque, but chances are not both). But that is a very narrow operating condition and 1 that is rarely used in a genuine road car.
Expecting a carby or 2 and a purely mechanical type distributor to be able to accurately deliver fuel and correct ignition timing in a force fed engine is even more rediculous.

And I haven't even mentione temperature compensations. Which are hugely important for correct and accurate running in the real world and even more so with force fed engines.

Tuning.................
Changing numbers on a computer screen and seeing the effect of those changes on a wideband air fuel ratio meter is MUCH easier than piss farting around with jets and emulsion tubes. The computer can deliver pretty much any injector open time within the available time frame. How many different jets and tubes do you have available to try and see what happens?
I have a couple of good books on tuning Weber carbies and from I recall, figuring out the Italian logic and the effect of emulsion tubes is more art than science.
Similar for ignition timing mapping. But that is more the domain of the dyno and having extra ears attached to the engine to listen for knock is a priority, especially if the engine is likely to octane limited in its ability to take high load ignition advance.

Ignition timing!
Nothing has more potential for damage, drivability problems and compromised power than incorrect ignition timing.
How on earth do people think they can provide the engine with the best ignition timing that the engine needs under any operating condition with a purely mechanical device???
Simple, you can't. So pretty much every aspect of the ignition timing will be compromised.
Again, temperature compensations are very important.

You can not tune a carby/mechanical advance distributor for something that it simply can't do.
It's like expecting a programmable computer to do something like control continuously variable valve timing when the makers of the system never implemented any means of doing so. You can't use and apply what isn't there.

I like Italian carbies too. But this is what's left of 2016 and I have a good quality programmable computer...............
The Motronic isn't worth squat in these cars. Alfa must have used the cheapest and nastiest version of the system they could. Too many compromises to make any effort to tune it to suit half resonable changes wasted time and money.

And I still don't know what to do with my 75. 

[jazig.k]

[Duk]

Into your 7 Series??? Nah man, the LS1 are a seriously over rated engine! 

[oz3litre]

And I still don't know what to do with my 75. 

Put the poor thing back together and drive it while you think about it.

[jazig.k]

And I still don't know what to do with my 75. 

Put the poor thing back together and drive it while you think about it.

[Duk]

Put the poor thing back together and drive it while you think about it.

Ahhhhhhhhhhh, No.

Well, kinda............. Maybe............

To me there aren't many things that are worse than rework. Doing things more than once is both painful and expensive. And I've potentially already done a few.

'IF' I can settle on a plan, I believe I have a suitable map for any of them listed in the first post.

Someone from some part of the world has even posted on GTV6.com recently, a decent solution to gain some transaxle durability.

Where I still struggle is in the badly located additional weight of the force fed engine variants VS the negative effects that weight is expected to have on the handling characteristics of the car VS my basic desire to have a very grunty and basically lazy torque monster of an engine...................

Read: I have had 2 big fat torque curve engined cars now and it's a hard habit to kick!

Appart from the additional weight issues of adding forced induction, 2 other problems nag at me.

The brakes and the definative decision of either a modified normally aspirated or (standardish engine) force fed!

I know I've ranted in the past about the brakes, but the more I think about the car's braking (and tyre!) capacity, the more I see it needs to be increased.
I created my inboard rear brake upgrade based on Series 4/5 RX7 Turbo calipers working on Wilwood vented rotors. And I'm sure if completed they would work well. They're a large diameter vented rotor and the calipers have MUCH more pad surface area.
And the handbrake mechanism isn't Italian.................... 
But those rear brakes and the old Volvo 4 piston caliper/164 rotor front brakes do start to look a bit feable when you start to compare them to similar weight cars with similar (potential, force fed) target power.
Think R32 GTR and Evo 6 onwards Lancers as a starting point.

The other problem is that of a modified normally aspirated VS forced induction.

If I went with an NA engine arrangement, then I'd be having the heads machined to bump up the compression ratio.
But obviously if I wanted to go with a force fed solution, keeping the compression ratio down around standard would be the best compromise I can make.
But because you have to take the engine out to remove the passenger side cylinder head, I'm not going to put the engine back together and reinstal it in the car just to figure out what I want to do. Engine removal, another pair of head gaskets and cylinder head machining after the fact is too painful.

It may not come accross the way it should, but I am genuinely thankful for you guys who participate in my mental wanderings. Extra info does actually help me sift thru my own mad scientist thoughts a bit more.

To add insult to injury, the Dr. Frankenstein ideas that I have for the front suspension and chassis should, in theory, help offset the potential negative influence on the balance/handling characteristics of badly located added weight of any forced induction.

[oz3litre]

It's all good fun thinking about these things and learning from others. The biggest problem for my son and I with the project black 75 is money to do mods with, so we are gradually doing things and driving the car in the meantime. It has come a long way since we bought it in undrivable condition, that's for sure. It now has a nice set of 17" wheels and tyres that have made a big difference to the drivability and appearance. The interior is coming along with the leather GT front seats, new carpet, reupholstered rear seat, Momo pedals, leather handbrake and gearshift boots and stuff. The next thing is to get new headlining put in and a decent set of front door trims. The engine runs beautifully, having been serviced by our Alfa mechanic all of its life bar one year and being a low mileage example. It is one of those engines that comes out of the factory a bit better than its peers I think. Engine swapping or big power mods are a fair way down the track at this stage. In the meantime, the red 75 needs the spare clutch kit fitted. It has been sitting for two years waiting for that. I have to dismantle the thrust bearing on the replacement clutch to lubricate it first. My son intends to keep that car as a stock example because it is in such good nick. The black one is the test bed for mods.

[Duk]

The more I think about this, the more I think that being able to add engine capacity and build a stout NA engine would be the best combination of performance, tractability and chassis balance.
I even started to mentally nut out an inlet manifold design with dual length runners and joined/separated dual plenum chambers (it's a 60* V6 and being able to join and separate the 2 halves of the engine should yeild improvements in the engines torque curve, especially when you have agressive camshafts that let you chase top end power).

But the big bore kits that are available are just so flippin' expensive!
2500Euros, plus freight, plus tax, plus block machining.

I started looking at the viability of finding semi-suitable sleeves and pistons from other engines.
The air cooled Porsche 3.6 litre engines use 100mm bores (not the 101mm bore the 3.5 kits use) and 2 valve per cylinder hemispherical combustion chambers. The bigger bore cylinders have their cooling fins as part of bore. So the bores are the Nicasil treated aluminium sleeves.
Then there are the custom made head gaskets.
So I pretty much thru that idea in the bin.

But re-reading some threads on GTV6.com says that the big bore kits don't exactly have a good reputation for reliability. Now some of the comments were going back a few years, but I think there may be an underlying challenge and that basically comes down to accuracy.
Really speaking, the sleeves should be machined from a single block of (suitable grade) cast iron rather than have individual sleeves. Then the block should be more rigid and the new bottom end could be accurately bored and honed to correct size and tolerance with actual torque plates bolted to the engine while it's attached to a crank tunnel fixture............... 

[oz3litre]

I have also heard of reliability issues with the big bore engines. A guy in Holland had one in his SZ and got sick of the problems and ended up putting a 3.2 in it. I am having trouble picturing how your idea of having liners machined from a single block would work. Can you elaborate further on that? It sounds interesting.

[Duk]

The best and most dramatic examples are from the NORD and TS engine block.
Grabbed from: http://www.autocomponenti.com/projects/two_new_records.htm I should have named it monosleeve.

[oz3litre]

Thanks. Now I get what you mean. I have seen those before. That looks like it would be an expensive process to make though.