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[RockersDelight]

What would I have to do to get around 170-180 bhp out of my 1.7 16V engine?
And what would it cost me?

I guess bore to 89-90 mm would do the thing but what would I have to buy additionally to match the new cc?

Thanks!

[Errol]

Hmm where to start? Without Supercharger or Turbo, you'd probably have to do the following.
- Cams
- Cam gears
- Exhaust/extractors
- Bigger injectors/valves
- Bore it out
- New manifold
- Better ECU software with Chip
- Lighten the flywheel
- Electric Water pump ( costs a bit , but adds 10bhp )
- Air filter set up

Thats all I can think of? Im suer others will add more
_________________
91 Alfa Romeo 33 16v * SOLD*
Lowered 45mm
15 x 7 inch advanti wheels
Falken 195 low profile
K&N Pod filter
Cannon 2inch exhaust from cat-back with 3inch tip.

[Marcin]

[rjbevan]

The speed of the mechanical water pump is dependant on the engine speed and at high speed the losses (in efficiency) will be higher. With an electric pump, the controller ensures the pump speed is constant (and also it can get the engine to warm up quicker). So if the mechanical pump uses 10 bhp (which I cannot confirm) then an electric pump power will be lower (but I can't say how much - look on some websites for electric pumps - there's one in Australia). Against that, the cost of changing to electric is not cheap, but you can put the pump in a more accesible place so its easy to get to!

Richard

[Matt Stolton]

My P4 project is aiming for 180BHP from a 1712cc setup.

The throttle bodies are more than enough to do the job, but you will need to remap/replace the ECU to get the most out of any revisions done. I expect top have to increase injector size too, but only a rolling road test/setup will show that up.

I am also using silly cams, which is a large part of the battle. Obviously inlet tract/filter is being revised, along with a more free flowing exhaust system. I will also get a full custom exhaust done when funds can allow.

In order to get power, you must be able to spin, fuel and shove air in the pot, so a complete rebuild of high quality, making sure everything is very well balanced is a must. Inspection and testing of crank and block has to be done thoroughly to save heartache and cash later. Similarly, rods, pistons etc, all need to be in tip top condition and balanced to as much as you can afford (0.01gr is nice if you can do it) to make sure the engine will spin without shaking itself to death and damge all your hard work.

The real power and power curve of the engine is then all down to head work. Alfa are clever buggers at the worst of times, and the 16V head has a number of features which can be 'amplified' to extract more power, at the expense of low down torque and day to day driveability.

All the real effort on my car is in the heads and the reporting/flowing/valve sizing that is going on. Whilst it is important to make sure filter/inlet and exhaust are done properly, they won't gain you power as such, a good system just minimises losses or removes spikes/dips in your power curve.

The main gains from 'Max Power' type filter/exhaust 'upgrades' are not gains in power, they are simply changing the compromise that the designers left in for comfort Vs performance, and shifting it in favour of performance. All they really do is remove a restriction on the standard setup, at the expense of something, generally torque or noise. To actually get more power output,you have to rebuild something, which will radically alter the engine's overall package. Head work is what you need, but done properly.

All I need now is 8 new valve springs (which are rumoured to be in the country now), dry assemble the block and heads to get the clearance correct between pistons and valves, grind the pistons to suit said gap, and put it in the car!! Sounds easy, but I'm sure lots will go wrong before it runs properly!!
_________________
Regards

Matt

Ex Alfa 33 'GTA' (P4 with Knobs On)
Now cruising in a 166 3.2 Ti!!

[Jan]

Hi Matt, what 16v head features do u mean that have special features ?

Greetz,
Jan

[Matty Dog]

I'm reliably informed there are power gains to be had by altering the position of the crank position sensor to allow some minute adjustment of the timing.
The suggestion I had was to slot the mounting holes so the sensor can be moved up by up to 2mm.

Can anyone comment on this?

Cheers,
Matthew

[Eddie W]

Matt
Can't quite agree with all your premises. As I understand it power results from the volume of air and fuel burned in stoichometric balance and the efficiency of the burn. Most engine modifications are aimed at improving the engines ability to flow more air thereby increasing the volume per cyl. In effect cams and head work are moderating the compromises that the manufacturer has built in. Therefor anything that impedes airflow into the motor(ie air filters) or restricts hot gas exit(ie exhaust) is a limiting factor on the engines ability to produce power. Improving the filtration with material of less restriction while retaining efficiency(K&N) should result in some power gain. Redesign to improve cold air supply( denser air= more charge weight= effectively more volume) and/or more direct supply to carbs/injection should also show gains. These gains may be small compared to major mods but incrementally they can all add up and are easy to do without any reductions ,in fact usually increases, in driveability.
We all know that a correctly designed extractor will also aid in cylinder filling by using a negative pressure pulse to " suck" more air into the cylinder, so more gains again. Ionce built a tuned extractor for a friends 2litre Escort rally car that put out an extra 12 hp at the wheels over the system he had before. Same dyno,similar air temp and humidity and the previous system was a factory supplied extractor. Albeit the more efficiently the lengths resonate with the cam timing,then the narrower becomes the band of peak efficiency.
Increased compression, I believe, improves the burn efficiency and the amount of expansion and therefor thrust on the crank.
Balancing components reduces the loads on the mains, the loads increasing linear with the revs. Lightening reciprocating components reduces the inertia loads on the big ends which increase as the square of the revs so light weight dramatically increases reliability and power because of the engine doing less work in accelerating and decelerating these components. So summing up,major gains are made internally but there are gains to be made externally.
Disclaimer: This treatise is written to the best of my ability using my tired old brain cells and no claims to any knowledge is implicit or implied.
Regards Eddie
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A LITTLE FURTHER A LITTLE FASTER

[rjbevan]

Matty Dog wrote:

[Matt Stolton]

Eddie,

The battle assumes stoichemetrics will be adhered to, so by saying i'm getting as much air in as possible, fuel is assumed to be there too.

Fuel is easy to pump in, just get a large hose, high pressure pump, and away you go.

My project is trying to get large amounts air in to the pots, to reach the stoichemetrics that you spoke about. My point was that filter, exhaust heads and cams/valves are generally restrictions to air flow, thus limit the amount of fuel the ECU will shove in, for its given map. If you increase the amount of air flowing into the pots, you can remap the ECU, or if it is setup already, get the ECU to squirt a corresponding amount of fuel to get optimum burn. Without super or turbo charging, coaxing air into and out of your pots is the battle.

However, most good aftermarket inlet and exhaust revisions are good enough to no longer be the limiting factor on the amount of air you can get to go past the injectors and into the pot. Hence why headwork and cams become the next step. Headwork and cams/valves are ultimately where it is at, if you want to revise the characteristic of the engine.

Perhaps I should change 'air' to read 'mixture', if you see what I mean

Jan

There is a certain asymetry to the 16V cam timing on the inlet valves. This also follows into the head.

The theory is that at low rpm you want to have a small valve open a small amount, thus making the gas speed high as the air goes past the valve, as the piston draws down the chamber. This will, if done correctly, give you low end torque.

However at high RPM you want the valve to be as big as possible, have as much lift as possible and be open for as long as air can be drawn in to the piston. This is why variable valve timing and other clever practices have evolved to allow the ECU to change valve duration and lift in response to RPM (The new BMW 5 series ECU has the hydraulic lifters change in oil pressure with RPM to give the increased lift with RPM, whilst the 7 series actually uses solenoids, controlled by the ECU, instead of cams to open its valves!! The Alfa TS engines employ variators to do the same sort of job, but a little more crudely).

The 16V hasn't got any variable valve timing, or variators or nothing. However, we do have are rather clever static system built in. If you look at one lobe of the 16V inlet cam, it is slightly leading when compared with the second cam lobe for the same cylinder. This gives the sort of effect we are after, in that at low rpm the one valve opening 'early' gets the gas flowing for as much torque as a 16V will give. At High RPM the significance of the early valve is lessened as the engine is trying to breathe as best as it can, so the two valves effectively breathe together.

The hot cams I've got amplify this effect a little more than standard. However the big work is in the heads. By keeping the 'early' inlet valve only slightly bigger than standard you keep the low RPM torque as much as this engine's design will alllow, obviously with some tradeoff's. The late inlet valve is made as large as is feasible, so for high RPM work the restriction to air entering the pot is as little as possible.

This asymetry is also at work within the head itself. The volume of air behind each valve is going to be different too, i.e. one valve has a large pocket behind it, the other slightly less. This will also lead to amplification of the original effect that Alfa put into the head in the first place. This asymetry of the air volume behind each valve is used in a number of current engines including SAAB and a lot of bike engines. My Engineers main work is in bikes, mostly 2 potters. He has likened the boxer to being just two of his bike engines (typically 900cc) strapped together!! As he can get (reliably,i.e. will last an entire season) 150+BHP from 900cc (admitedly with little torque, and at 15000rpm) he is worth listening too. We are going for a more user friendly approach, sacrificing top end power for low down Torque, so 180+bhp from 1712cc becomes very achievable.

Once it is on the road, mapped and the like, I will be showing it off as much as possible.

(Still waiting for the bloody Valve springs which are still in Italy somewhere....)
_________________
Regards

Matt

Ex Alfa 33 'GTA' (P4 with Knobs On)
Now cruising in a 166 3.2 Ti!!

[Marcin]

Here's the theory applied in practice:



This one is on sale at the Dutch "www.marktplaats.nl". They are aiming at 9000euro. Some features: 2.0 engine from 155, turbo, NOS

Marcin

[johnboy]

[quote="Marcin"]Here's the theory applied in practice:

That car is awesome, ive got a picture of it in my gallery not sure about the filter but it would work better than it look's. nice having an integrale lump in it with 215 bhp to the front wheel's would be fun

all the best
john
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WODA WE NEED? MORE POWER!!

Alfa gt jtdm blackline
1990 S2 16v veloce sleeping!
2002 ts gtv the wifes now
1997 seadoo gsx 800
1999 freestyle superjet

[Guest]

So how on earth did they get a 155 engine in there? Is it still FWD? Why didn't anyone tell me about this when my 16v boxer engine needed a rebuild?

Seriously - has anyone got any photos of under the bonnet?

Adam H