Alfa Romeo Forums banner
1 - 3 of 3 Posts

·
Registered
Joined
·
222 Posts
Turbocharge!

Tuning a naturally aspirated engine will cost you $$$$$$ and you will just be moving the peak torque higher and higher. Carbs or EFI, to get any decent power increase on a 16v you are going to need to improve the induction, port / polish the heads, larger valves?, skim the heads, deck the block, new cams (there are 4 of them! $$$), perhaps larger injectors??, new exhaust, oh and remap the ecu (or buy a completely new one?!), if you are running carbs you will have to tune them on a dyno. Actually, you will need to do that with a new ECU anyway. So the advantage of carbs is?????. Carbs start to make less sense on the 16v when you consider they are not even a simple bolt on. You will need to make the linkages, and have the inlet manifolds custom welded.

What else? Oh, because your peak power is now at 7500+ rpm you may want to strenghten the internals. Perhaps new custom made pistons? $ Or new forged con rods $$, Shot peen the crank$, blueprinting $.

The 16v is already highly tuned out of the box. Alfa did a very good job. 99kW from a 1.7 naturally aspirated engine? That is very impressive, especially considering it was made in 1990.

I am not saying you can't tune a 16v for more power. You can! But you are embarking down the path of diminishing returns for your $$. You will be building a cranky, temperamental, high rpm screamer that will refuse to idle properly, with exactly zero mid range torque. The torque on the standard 16v is bad enough! Awesome for a track car, not so good for a road car.

130kW ATF from an exhaust and chip? Lenus I'm sorry but that is fantasy. Dyno reports often greatly exaggerate the flywheel outputs because they bluff the results in 'shootout mode'. Even the best exhaust on 16v will net you about 10% extra power max. This has been confirmed time and again on naturally aspirated engines from just about every manufacturer in the world. Especially highly tuned 16v motors. And a chip? They just advance the timing 1 or 2 degrees in a few spots, and marginally enrichen the mixture here and there. Basically they take away the manufacturers 'safety margin' to account for all loads and temperatures, low octane fuels etc to prevent pinging. A chip will net you 3% extra power, being optimistic. Only if the motor was originally tuned by a dunce will a chip help. I have never thought of Alfa engineers as dunces.

So why am I a fan of turbocharging? Now I am not foolish enough to believe that installing a turbo is easy, it will also cost you money, but I believe the end result is better value.

A well selected, mildly boosted (8psi) turbo will increase your peak torque by
around 20% throughout most of your rev range. Of course a 20% power increase follows. So basically a turbo will emulate having installed a motor of 20% more capacity in your sud. So whats that? A 2 litre! nice.

Modern turbos have almost no lag, if they are well selected. If you want more peak power, select a peakier turbo. Your peak power may reliably climb by 30% or more.

A well set up turbo can maintain driveability, fuel economy, and make a car much more tractable. A small, low lag turbo with torque everywhere will make your car a blast on the road, allowing you to accelerate hard out of corners, even if your revs have dropped below 4000rpm.

The good news is that with perhaps a larger fuel pump and injectors, the stock Fuel injection system fitted to a 16v should be able to cope with a low boost turbo just fine. If you need to slightly modify the mixtures and ignition mapping, you can install an interceptor chip. If all else fails, you can install an aftermarket ECU. I doubt it would be needed. An on-boost ignition retard and adjustable fuel regulator might be all the $ you will need to spend.

As Carroll Shelby said: "Horsepower sells cars, but torque wins races"
 

·
Registered
Joined
·
222 Posts
I agree. A mildly warmed over 16v with intake / exhaust will give you about 150hp. And yes, for a car that weighs under 850kg (your series 1) That is more than enough power for the street. The power to weight ratio even eclipses some modern hot hatches. If you can get the power down (sounds like you won't be having any issues) I'd say you'll do the 0-60 (mph) in about 7.5 seconds.

But I would still advise anyone going down the 'heavily modified' route to consider a turbo. :D
 

·
Registered
Joined
·
222 Posts
I wouldn't recommend turbo'ing a carb car. That is too much work for marginal results. If you want to turbo a carbed sud, get some IDF fuel injection throttle bodies (they bolt straight on in place of the carbs) and hook them up to an aftermarket computer.
Or install a later fuel injected motor.

There is alot of plumbing involved in installing a turbo in a boxer engined car. But one of the most famous turbocharged cars in the world is a boxer. The WRX. It can be done.

Of course you can fit a turbo to a sud. It has been done many times before.
Two companies did back in the 70's and 80's - wainer and bell and colvill. There have been many other conversions since.

As for intercooling, I'm sure you could fit something up front with some work. The import crowd do it all the time on far smaller cars! Or you could top mount, like subaru do, although a scoop would be necessary. (It can be done tastefully)

A supercharger is something that has been done perhaps even more often than turbo's on suds. It is an excellent idea. Probably less work too.

And of course, if you go nuts with the boost, a turbo will blow something. They can be set up reliably however. Many modern cars have turbos, even reliable, boring diesels.
 
1 - 3 of 3 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top