spica performance potential/limitations.

[SquadraNolo]

I am in the process of building out a 76 spider 2000 (spica) for racing. I am curious of any potential limitations the system has as well as performance tuning modifications and horsepower potential. I know, buy wess ingrams book and go from there. am buying the book, but have to wait for shipping to arrive.

kevin

[Richard2]

1. Remove SPICA.
2. Send to Wes with engine specs.
3. Enjoy the winners circle

[otmills]

Richard, if you find any info along the way about the (mechanical, from '73 Spider) injectors themselves, please post or pass along. I can't help you with your performance question about the pump but am very surprised that there is not a single post in the archives about the actual injectors and servicing them. Like, what the psi line pressure from the pump is to crack the injectors for testing. Guess I am heading to Wes Ingram like everyone else.

[davbert]

Quote:

Originally Posted by SquadraNolo I am in the process of building out a 76 spider 2000 (spica) for racing. I am curious of any potential limitations the system has as well as performance tuning modifications and horsepower potential. I know, buy wess ingrams book and go from there. am buying the book, but have to wait for shipping to arrive. kevin

[genericwood]

Kevin, you didn't mention what type of race engine you are building and why you are wanting to stay with the Spica. For example, if you are building a F-Production SCCA car, you are limited to the stock, unmodified throttle bodies. That could be limiting. If you are building a vintage car, you can go to an oversize throttle body. If you are in the Northeast, you may want to speak with Eliot Shanabrook, he runs a successful vintage racer on Spica. If you are in the Great Lakes area, it would be worth talking to Eric Storhok. He's been building a vintage racer with Spica for some time, and is a Ford Powertrain Engineer. And of course, Wes Ingram is the real expert.

I have a modified pump on my street car and am generally a fan of the system. But I do run Webers on the race car. It's just a lot easier.

Erik

[SquadraNolo]

what I am planning is a hot street/race version. if officially raced, do it vintage (less limiting than scca). what would be the best (most competitive) class to build it for? main reason for keeping the spica system is three fold. first, I already have it. second, I believe if set up properly it can provide more performance than carbs. third, novelty (never have done things the easy way...if I did would not even be using alfa).

kevin

[Clayton105]

As far as injectors are concerned, any decent diesel repair shop can throw one on a tester and check them for leakage, pattern and crack pressure. Not sure about servicing them though.

Once the seats are not able to hold pressure, it would be a task to get them right again. I have tested them and pulled them down to see what goes wrong. I found on some that I pulled off a Monty the needle springs were broken, and just replaced them with injectors off a 4 pot. They seem to be the same.

Once upon a time I was obsessed with this lovely old system, and wanted to build a GTAm replica using a T-S and Spica (to make it more athentic), so I put a fair bit of thought and research into using it.

I see no reason why you can't use Bosch K-Jetronic injectors. In fact, once I saw a picture of an engine on this forum where someone had done just that. They also had used flexible lines, just like a GTAm. As K-Jet uses lower pressure this should be no problem. I would also think that the lower injector pressure would translate to lower parasitic losses driving the pump. The fact that Spica injectors are designed to inject sequentially (stop/start) and K-Jet is continuous is negated by the fact that K-Jet injectors are designed to "Chatter" at low deliver rates.

[genericwood]

Quote:

Originally Posted by SquadraNolo what I am planning is a hot street/race version. if officially raced, do it vintage (less limiting than scca). what would be the best (most competitive) class to build it for? main reason for keeping the spica system is three fold. first, I already have it. second, I believe if set up properly it can provide more performance than carbs. third, novelty (never have done things the easy way...if I did would not even be using alfa).kevin

[Rosenmöller]

Quote:

Originally Posted by otmills Richard, if you find any info along the way about the (mechanical, from '73 Spider) injectors themselves, please post or pass along. I can't help you with your performance question about the pump but am very surprised that there is not a single post in the archives about the actual injectors and servicing them. Like, what the psi line pressure from the pump is to crack the injectors for testing. Guess I am heading to Wes Ingram like everyone else.

[Roadtrip]

Generally, the stock pump can handle hi compression pistons and a European cam. Much past that and you need a modified injection pump.

[Rosenmöller]

Quote:

Originally Posted by Roadtrip Generally, the stock pump can handle hi compression pistons and a European cam. Much past that and you need a modified injection pump.

[turbolarespider]

For this instance, I had the same reasons to go with fuel injection.

And at this point, leave it at that- fuel injection instead of carbs. There are two choices you can use- Lucas or SPICA, and the CRH lists both- so both would be accepted at any vintage race.

First and foremost- can it make more power- yes it can. Alfa used Lucas injection for a reason- it could make more power. Can we get a set of slide throttles? Not likely. But an increased bore diameter will be less restriction than the 45mm DC series- since they HAVE to have a venturi to draw in the fuel. From what I currently know, the stock set up is good to about 42mm, before things need to really change. I'm going to look into 45's, but don't hold your breath- this is a hobby, not a real job... I do have a set of modified throttle bodies from richard, and will use them on the ITB engine that's currently in the car to get familiar with them.

Second- how in the world to set it up?

The most generic answer to that is to copy the CRH, which does have a SPICA part number listed along with the LUCAS set up. I've been e-mailing with Don Black about this, and for the most part, the SPICA part is the same pump w/o the logic secion. Which is essentailly what the LUCAS system was as well. The pump section is more than capable of running with the most powerful 2.0l ever made (normally aspirated). It just takes a bunch of tuning.
It's interesting that you bring up injectors- as this has been a part fo Don and my conversation.

The 150 psi injectors that Alfa used for our cars was more for the cold start than anything. And the 39psi injectors that Bosch used for its mechanical system will work- that's what most EFI systems are tuned at. If you are worried about atomization- well, cold- yes, it's a problem. But hot, no it's not. If you use the stock location, once the engine gets up to full operating temperature, you will be injecting vapor anyway- 39 or 150 psi.

One OTHER reason to go with the lower pressure system is "period correct". See, if you read the CRH, it clearly states that the SPICA racing pump used the low pressure LUCAS injectors- which are also at ~39 psi. Pretty cool, if you ask me.

Finally, there's one other, theoretical, reason. Well, sort of theoretical. One of the early posts correctly points out a concern of Wes'- vibration. But some e-mailing he and I have shared- it turns out that if you use flexible lines, much of this vibration goes away. IMHO, going with the flex lines that are commonly available is a much better match for the low pressure injectors.

I would like to note, it's not as simple as going with the low pressure injectors. There are two check valves in the injection side of the pump- one on the exit of the pump, the other- the injectors. These check valves are to be the same- so you'll have to send wes the pump to modify this set of valves, too.

Now the tricky part. Tuning.

The base tuning with out the logic section is pretty straight forward- there are very few "knobs" to turn. It will take some time, but can be done. (needless to say- plan on using a wide band exhaust sensor. it's the only way to get it right)

What I hope to do is to actually modify the logic section to make it work, too. I have a few people who are willing to help me with some machining once I get to that point. But my desire is to make sure that my car will run right more often than with the simple logic, as I hope to autocross the car, which uses a lot more of the entire engine range than most race tracks do.

It's going to be a fun project- but first things first- I've got some more body work to finish, and get familiar with what I've got before I start digging into the fuel system.

Eric

[Clayton105]

Just for those that are interested:

I read once that Autodelta prefered the Lucas pump to the Spica because it had lower parasitic losses. This is because the two pumps differ in the way they function.

The pressure to force the injectors to open in the Spica system is totally generated by the mechanical effort drawn from the engine via the belt. The drive belt serves two funtions: to provide pumping effort and distribution timing. The fuel pump merely ensures a supply of fuel to the injection pump. Therefore, the parasitic losses (even if you lowered the injector pressure and got rid of the logic unit) would still be measurable as you still have to drive the little crank , con rods and pistons.

The pressure to force the injectors to open in the Lucas system is totally provided by the electric fuel pump. The drive belt is only used only to drive the distribution sleeve. While the floating shuttle (piston) is driven back and forth by the fuel pressure. Therefore, the parasitic losses are insignificant.

I have had a look at one of these proper GTAm Spica pumps, and should still be able to get access to it. Should not be a problem to get pictures and measurements to produce drawings of the bell crank system.

For all out racing, the system would be fine except for some part load situations (I think I remember reading that they were not great here), and would require a lot of dyno work to get an ideal mechanical relationship/compromise between the angle of the thottle plates and control rack.

If only there was more time to pursue all my interests....