Alfetta power upgrades

[Grant]

Hello all,

I have a '79 Sprint Veloce. It's stock except for some old Shankle Headers. That being said, it's really slow. Fun to drive, but really slow.

If I were just shooting for 125 fly wheel horsepower (instead of the 105 or whatever it's making now ) would I be able to just get some mild cams to achieve my goal?

I'm looking to increase mid-range punch more than anything, and I'd like to try to keep whatever semblance of gas mileage I can.

So, from what I've been reading, the euro cams (01, not the 51) aren't good for use with spica because the duration is to great? What should I use then?

Thanks for the help!

[Grant]

Chirp chirp.

[Andrew]

If it's slow, the first thing to check is the basic condition. To have an engine that makes anywhere near 125 HP, it'll need to be in at least good stock condition. So check compression, cam timing, injection setup, etc. Then consider modifications from there. Most of the HP comes from head modifications. Cams, valves, exhaust changes.

The Euro cams are great with Spica; I have them on my Berlina and my GTV, and are a nice pickup, but are not really much more power. The do make the car feel more alive though.

A 79 Sprint Veloce in San Jose is going to need smog checks, so you'll need to be careful what you do if you want to continue to be legal.

If I were trying for that range, I'd make sure the bottom end was sound, maybe go with the Motronic pistons, get a good valve job with larger intake valves, put in Euro cams or maybe the next level up, and leave it at that. Shankle headers made worse power than stock headers on 105 cars except at extreme RPM; I have heard they are better than stock on 116 cars, but tube headers tend to be best at RPM, and will give you less power and torque at low RPM. Again, I don't have specs for a 116 car, but that's a typical reaction.

Find an engine shop you want to work with for machine work etc., tell them what you're after, and see what they recommend.

Andrew

[Grant]

Thanks for those tips.

I have yet to do a cylinder leak-down test, I'm not sure it's needed. I have receipts for recent head work and the bottom end appears to have fewer than 100K miles.

I guess I'm still looking for cam recommendations. Richard Jemison was talking about Euro cams and Spica not going well together.

[Andrew]

That's not my experience. I have 10548 cams on my carbed Super with 1750, Spica 2000 in stock Berlina, and Spica 2000 with big intake valves on GTV track car. I am happy with them all. Tom Sahines and Norman Racing both recommend them for Spica or carbed cars. I think it's best to pick one guru and take his advice. Different people have different views, and sometimes they conflict.

As I say, they are more torquey, mid-range cams, not high-rpm HP cams, but for what I wanted they are great. There are better choices if you want HP way up the range.

Andrew

[Grant]

Have you noticed at all if fuel economy has suffered? Are euro cams hard to get a hold of?

[Alfajay]

Grant had written: "I have yet to do a cylinder leak-down test, I'm not sure it's needed. I have receipts for recent head work and the bottom end appears to have fewer than 100K miles."

Grant: If you want my advice (and you probably don't), then you are going at this from the wrong direction.

Before slapping some new cams into your Alfetta and expecting a complete transformation, I recommend that you check EVERYTHING related to tuning. Check the compression, ignition, and the Spica pump. Testing compression is easy, and will tell you a LOT about the condition of your engine. Reciepts for recent head work mean nothing - who knows how well the work was done? An engine with 100K on it could have leaky rings (as well as bearing issues, though that won't effect the power output). Check the ignition with a timing light. The best way to check your Spica would be to have a pro put an exhaust gas analyizer on the car to make sure the mixture is correct across the rpm range.

Once you have maximum power from the stock configuration you can begin adding performance parts. But, putting cams into an engine with an unknown state of tune - especially one you suspect to be down on power - is likely to disappoint.

An ebay seller in Italy, "Alfa1750", usually has the 10548 cams. Or find them at an ARA swap meet.

[Andrew]

Yep, that's basically what I was saying above. First figure out if the engine is running right, unless you don't care about the current engine and just want to jump in and do a rebuild/upgrade regardless.

Don't forget an Alfetta is going to have a smog pump, which will affect power, assuming you plan to stay legal.

Andrew

[Grant]

I understand your guys' concern for me not checking the basics first. However, I'm doing research right now. I never said I was going to jump in and slap some cams in. I'm even planning on reading Jim K's book as soon as it arrives at my door.

When I do put cams in, I'll probably have the head off to do some very mild porting and cleaning. If something needs attention, I'll address it then.

I don't get the air injection pump theory. All it does is inject air into the manifold right? Is the power loss just what's necessary to run the pump, or does injecting cold air somehow inhibit exhaust scavenging?

As far as Spica mixture, I have an Innovate LM-1 (wideband o2 sensor) so as soon as that's installed i'll do final tuning.

[Andrew]

The pump itself saps power to drive it, but also the mixture that is intended to work with is not the best for power.

Andrew

[Grant]

So, if I get the mixture to be correct for power under full throttle, the pump will only be a hindrance because of the power to drive it then, right?

What kind of mixture is the pump supposed to work with? I'm assuming a bit rich, so NOx is low?