105 v Alfetta v 75 Track Times. Whats better?

[Alfatango]

Hey all, I was watching this video at PI of a 105, Alfetta and 75 all following each other https://m.youtube.com/watch?v=c_i8eNmFTFw . No one is really pulling away from each other.

So this leads me to a question, whats the better base to build a car to get the fastest time at a track like PI? But more specifically from a financial perspectice, what makes a faster race car an alfetta or 75? Because there are LOT of alfetta race cars that come up for sale compared to 75s. Also if money was no object would a 105 with a similar build be faster than an alfetta or 75?

Also would anyone have the factory weights of just the engine for all the engine options for all 3 cars?

[MD]

Alfatango,

Great to see enthusiasm out there. Never let that die. However, your choice of an Alfa Romeo vehicle (any contempory street model) for a Time Attack application is frankly pissing in the wind.  For many and different reasons, none are specifically suitable for that purpose. Some are tail happy, some have weak and slow gearboxes, some are too front heavy and out of balance and  so on.That is not to say these same cars are not fit for the purpose they were made for in the first place and often small refinements make them a sheer joy for the original intended purpose which is not Time Attack.

Your judgement about the pros and cons of the vehicle you have nominated and running at PI in the video link is a complete  waste of time. We have no idea of too many variable factors why one car does not pass another.

Driver ability
Driver confidence
Relative engine power
Relative gear ratios in use
Comparison of tyre compounds
Amount of weight reduction
Chassis development  to name some

None of the above is known from a simple viewing of that video and so no judgment can be made whatsoever.

If you decide to dismiss my views and carry on, about the ONLY tip I will give you is to start by concentrating on the best possible power to weight ratio.

If you insist on dreaming on and you imagine that money is no object, buy a Sud Sprint. Tear all the guts out of it. Do a 4 WD conversion. Install DC motors front and rear with a battery pack in the centre . Invest in some welded on underwear 'cause the this Alfa will tear the fork outta yer nightie. 

[MD]

A bit more on the problems of choosing cars. A power to weight example.

Take these two 4 door 5 seater street version sedans as comparisons:-

Alfa 75 series 1.6 litre version in Italy weighs about 1250kg
Datsun 1600, 1.6 (so called P510) weighs about 850kg

So the same 4 door 5 passenger cars have a difference with full trim of 400 kg. That is a HUGE amount. Is it any wonder the P510 was such a global success in rally work for two wheel rear drive cars !!

[MD]

If you examine the technical specs of the 75 and the Alfetta in terms of weight, you will find not much appreciable difference.

[MD]

Perhaps I should let other knowledgeable members provide some responses for you from a likely different perspective . I am sure others will agree that to get into Time Attack times, the biggest prerequisite will be deep pockets whatever car you finally chose to work with.

[Sheldon McIntosh]

As with MDs response, too many variables in your original post.  The Alfetta Group S is a 2 litre twincam, the 105 is I think a Group S, so probably a 1750 (but I don't know, could be a 2 litre), the 75 is a TS, probably standard engine, but I don't know, so no way of knowing which has what power etc.  Let alone getting into driver ability, tyres etc.

But just some thoughts, some based on experience, some on anecdotes.  105s will be a bit lighter than the other 2, but handling a bit more tricky on the limit.  Alfetta and 75/Giulietta/90 are all far more neutral handling due to the transaxle, providing far more balanced weight distribution.   Alfetta will be lighter than a 75, but not by much, shorter wheelbase so should handle better than a 75, but the 75 would be a little more stable at a fast track like PI. 

Then, which engine would you like?  Of course, money being no object, any engine can be fitted into any car (within limits).  But realistically, the most powerful you'll get into a 105 is a TS with some serious modifications.  With an Alfetta or a 75, well, if you're going for outright speed, you're looking at putting a V6 in, or just getting a GTV6 or a 75 V6 in the first place. 

Personally, with the prices of 105s and Alfettas these days, no way I'd be turning one of them into a track car.  And 75s are starting to go that way also. 

I'm surprised you say you've seen more Alfetta race cars than 75s, that wouldn't be my experience.  And watch all the Alfettas and GTV6s get turned back into road cars in the next few years.....

I'd be getting the cheapest 75 or 90 with a V6 I could ASAP if you were serious about it.  And then plan on spending a LOT of money making it fast (does anyone even make big torsion bars these days?).  Or, just buy the quickest race car already built you can find, they are out there.

Or you can buy my slightly rusty 90 sitting in my yard if you want, comes with a free bolt-in rollcage!!

[Sheldon McIntosh]

And just to mix things up, here's another vid from the same event as your original post, me in my 90 with a 3.0 12v, against a 1.5 Alfasud Sprint 1.5 with a faster driver.  Which car is faster....?


https://www.youtube.com/watch?v=clgfR4qyMjQ

[aggie57]

Sheldon is right, a 116 series car is by design better suited to tracks like the Island.  In the early days there, back to back Alfetta's were faster than similar spec 105's.  You can feel it on the track at corners like turn 1 and Lukey, a 116 is just more stable.  I remember following Frank Porter around the very first day we had access to it after it reopened, him in an auto 75 demo and being amazed at how settled it was in fast corners. 

On tighter tracks like Winton the difference is less pronounced, if anything the better immediate turn in of a 105 helps.  But even then with a few mods you could get a pretty standard 116 coupe around the short track faster than a similar 105. 

Why are there more Alfetta GTV's than 75's?  I've been out of Oz for a few years but in the early days you could buy a GT/GTV for not much money and really nobody wanted to punt a sedan around.  People like Michael Ponchard did wonderous things with 90's and suchlike but that was the exception. 

[Alfetta77]

My two bobs worth - the coupe design of the Alfetta has been more popular, and they haven't been as rare as 75's (although getting that way), so more have been either raced or restored. Don't get me wrong, a nicely done 75 can look awesome, I just don't think as many people have been inclined to put time / effort in. There are still Alfetta project cars out there for circa $5k so I say go ahead and build a race car if you want to, I hear you re historic livery too. Something I would like to do myself one day (if I ever finish my road car 

[Joe Falcone]

Hi guys
From my experience id have to say that a well sorted alfetta gtv with 20l ts engine and gearbox

[Joe Falcone]

is the way to go

[vin sharp]

 ::)Good GpS historic Alfettas and 105s will do 1.54secs and under at Phillip Island, with 60+ year olds driving... That's with a Nord engine on carbs, 185/60 treaded race tyres and standard size solid brakes and calipers, and all steel body. An equally set up 75 would match that or within tenths.
How many very modded, stripped & lightened Alfas ever get near that potential?   

[MD]

In your line up, we don't have a comparison of apples with apples.

For a true comparison, the vehicles would have to be modified so they have identical power to weight. Use the same control tyres and brake materials. Getting equivalent suspension set ups would be problematic.The same driver would need to do the performance tests. All a bit of a mission so your best research would be to follow the Alfa racing globally and see which cars consistently perform the best or have done so in the relative past.

Once you make a choice then get cranking single minded until your world beating Sud is accomplished. 

[aggie57]

::)Good GpS historic Alfettas and 105s will do 1.54secs and under at Phillip Island, with 60+ year olds driving... That's with a Nord engine on carbs, 185/60 treaded race tyres and standard size solid brakes and calipers, and all steel body. An equally set up 75 would match that or within tenths.
How many very modded, stripped & lightened Alfas ever get near that potential?   

Remember when sub-2 minutes was considered quick?  Is it tyres that have improved this much or?

[vin sharp]

Until a driver can consistently be winning the class or right at the front of the class for his current car, getting the maximum out of both the car and driver, it's pointless to chase theoretical times in modified cars.
There's nothing more comical than seeing a flared, lightened, winged and spoilered, all-tech DRM/Supercar lookalike being flogged by a relatively stock looking car with 6 inch rims, skinny tyres and a 1950's engine design with carbies!