Alfa Romeo Repair: Bosch electronic ignition management, showroom stock cars, vw rabbits


Question
Dave,

Thanks A LOT for the previous help with the Spider transmission question. I will let you know the outcome when I open up the case this weekend.

I would very much like to prevent embarassment by the local Honda boy racers when I get my `82 Spider Veloce going soon. One area I am interested in improving on is the ignition. I understand that there are many upgrades available commercially. My question is this: If I go with a distributor system with capacitive discharge, and remove the flywheel reference and RPM sensors, ignition computer etc., how will the L-Jetronic get it`s RPM signal? I know that there is an interface wire between both the ignition and injection ECUs, but I don`t know if that provides the RPM signal to the injection ECU. Any recommendations for a low cost and powerful system upgrade would be of great help. Also, what do you think about simple performance upgrades of the stock system (i.e. coil etc.)?

Answer
Hi,

Sorry about the delay in answering.  I usually try to answer the same day but I had a nasty week.

It would take a lot to blow away the "Riceboys".  Some of them have a small fortune in their cars and they are awesome in acceleration.  We run a L-jet car and sometimes get fits from Miata's and Neon's even though they aren't in our class.  The newer "Showroom Stock" cars are loaded with goodies.  One we have never been able to catch is a Nissan Sentra SE-R.

In our class, "Improved Touring", most of our competition comes from VW rabbits, BMW, Volvo and other Alfa's.  We have finally gotten to where we can run with and usually beat the SPICA injected Alfa's.
The weak link in your car, isn't the ignition.  It's the fuel injection.  It's very reliable for the street and runs good cold, hot or in between, but air flow is too restricted.

First I'll answer your question then go into some other ideas.

We ventured into ignition without really knowing what we were doing in some ways.  I know that the EFI doesn't need a crank position signal, because we are still running the EFI but run a point distributor.  In fact, the bell housing we are currently using is from a SPICA car and there aren't even any holes for sensors.  Personally, I recommend if you desire to change the ignition, call Rick, at RML Automotive, in Daytona Beach, Florida.  Rick sells ignition systems all setup.  They use a BOSCH distributor with a Crane system (formerly Allison) and they seem to work very well.  I don't have his number handy but just ask for RML Automotive in Daytona Beach.  The area code is 904.  There are other ways to go, but his are all set with the proper advance etc.  I don't recommend points at all.  They just seemed to work for us.  I think we will be changing to Rick's system later.

I'll tell you what we have done and then recommend some things for you.
Our car has no Aux. Air device, cold start injector, throttle position sensor, O2 sensor, thermo time switch etc etc.  The AFM has been modified some and we run a variable resistor in series with the Coolant Temp. sensor so that the mixture can be richened from the cockpit.  This is a simple and dollar for dollar, pretty effective.

The BOSCH system is designed so that when the coolant is cold, the ECU richens the mixture by increasing the duration of the injector pulse.  As it gets warm, it leans out.  When it's hot, it's really lean for emissions.  The hotter it gets, the leaner it gets.  The leaner it gets, the hotter it gets.  By inserting a 300 ohm potentiometer in series with the sensor, you can fool the ECU into thinking the engine is cold and it will richen the mixture some.  It works great for a little extra help on very hot days.  It also works good on dry cold days when the air is very dense and the engine can handle a little extra fuel.

Another thing you can do is install an air filter that flows better.  We were at Daytona on the road course a couple years ago and we were running a stock paper air filter.  I noticed that when you open the throttle suddenly from idle, the air hose collapsed some.  I told Steve I was removing the air filter completely.  Daytona is all concrete pits and there isn't much dust, so it was not a big deal.  On the superspeedway portion of the track when he was flat out in fifth.  He radioed back that he had picked up a full 250 rpm without the filter.  Later, we installed a K&N stock replacement filter and it was the same as NO air filter.  I recommend that also.
You may have trouble finding one, since their application catalog isn't very good.  They DO make it but it's listed for something else.  I think a Alfetta 2000 GT or something.  If you talk to a distributor and have them actually look through stock after you give them the measurements of yours, they will be able to find one.  Don't guess or just order one they list for the Spider 2000, cause it's for the SPICA cars.  

We are currently running one of their Fuel Injection Perfomance kits that is made for a non turbo Supra.  Like a 1987 or 1988.  The AFM is nearly identical and the adaptor fits the BOSCH AFM without much modification.  The only problems are that you remove the stock airbox which is also the mount for the AFM.  You need to make a bracket to hold the AFM.  This is a large cone filter and the drawback that I see is that it's drawing from that nasty underhood hot air.  In a racer, the underhood air is being exchanged constantly but on the street at slow speed, it might actually hurt performance.  I'd stick the the stock airbox and the K&N pancake filter.
Another area that can give some improvement is exhaust.  We run headers, but the older double "Y" manifolds from a SPICA or carburated car is just as good.  They are available from several sources but I don't know if they are any cheaper than headers.  For the street, I have to say that the STEBRO mufflers are the way to go.  They are more expensive than ANSA, but they are Stainless Steel and are guaranteed forever.  Nice sound too!

There isn't much else you can do without cracking the engine open or replacing major parts.  Head work, cams, pistons, and finding a rear end from a SPICA car, can all help a bunch.  

Your final drive is 4.10:1 and the SPICA cars used a 4.55:1.  This kills economy some but really pulls better.  We are running a rear from a Berlina sedan.  It's 4.88, but I don't recommend that for the street.  Pistons from the later Motronic cars are a full point higher compression (9:1 vs. 10.1:1).  Cams are a little tougher.  Sperry Valve works sell a regrind and several other companies make them also.  We run Euro fuel injection cams, commonly referred to as "10548" which is the last digits in the part number. They are very hard to find, however.  Steve, actually carried two sets back from Italy for our racing.  Head work is not a big deal once you get it off.  I do our own myself.  I've done them for other people too and it's worth about 10hp throughout the rpm range.  Mike Sperry, does special heads for Alfa but they are VERY expensive.  We run a 1300 Giulietta in Vintage and the Sperry head on it was $1200.  I do them for about $600 including oversized valves and bronze guides.  The Sperry head gives it's HP only on the very high end, but mine are flowed to give a decent boost at lower RPM too.

I'd start with the Air filter and added resistance to the Temp sensor.  You can get a "Pot" for this at Radio Shack for a couple bucks and it's simply wired in series with either one of the wires on the sensor.  With the "POT" turned all the way off, you are working off the sensor by itself and when you turn the pot up... you can hear it burble when it gets too rich.

A lot of this stuff depends on where you live and if there is emissions testing there.  The filter and the pot, won't change your emission levels. (if the pot isn't turned up).  We put a knob on the pot, from a surplus store that has numbers on it like a volume control for an amplifier.  That way, you have some reference on where it runs best.  I don't recommend removing the cold start injector, Aux air device or that other stuff on a street driven car.

Well... I've probably confused you some, so if you have any further questions, write back.  I'm glad to help anyway I can.  I'm quite sure we have the fastest L-Jet car in the country.  NO ONE races L-Jet, since the SPICA cars will give a full 15 more HP no matter what you do to the L-Jet and they run in the same class.  We have won the Central Florida Region, SCCA championship several times and have won the SARRC (South Atlantic Road Racing Championship) twice and never finished lower than second.  It's usually because we missed some races.  You could actually get more HP than our racer, because we are so restricted by the rules.. and we ARE legal.

Dave Miller
Team Manager
Piantieri Motorsports