като заклети класици и маняци на конете 75 3.0 12в би-турбоо
за оплакване на окото малко старо инфо на забравено от нета
History of the project
This Alfa Romeo started life as a stock standard 75 2.0 TwinSpark. I purchased it in 1995 from the first owner. After exploring it's limits for a couple of months my demands were raised. Not quite happy with the handling of the car I started fiddling with the suspension. The car did handle quite well after some minor modifications. At once this resulted almost in crashing a company car because I was used to the handling of my Alfa.
Originally equipped with a TwinSpark engine it wasn't what I expected from it. Somehow the engine didn't perform that good. At some days I was overtaken by snails and at other days few cars could beat it. A check up at the Alfa dealer didn't prove anything wrong. They checked the engine control system but nothing was wrong with that. In a weekend of desperation I discovered the intake camshaft timing changer jamming sometimes. I put on a new one but it didn't cure the engine. Ever since I had had the car the airflow meter cover had been loose, could the problem be in the AFM? I replaced the airflow meter and ... still no power. What I did notice was the difficulty to control the CO rate. A vacuum leak then? After a thorough check of all hoses a vacuum leak could not be discovered. After putting some time and money into the engine I got frustrated and I decided to really tune the engine. The only way to real power increase was in seriously modifying the engine.
I went to some Alfa shops and inquired for possibilities of tuning a TwinSpark Engine. I found out that it costs a lot of money for only a few HP. So I looked at purchasing a 75 3.0 V6. The only problem is that people want an awfull lot of money for a high mileage V6, just because it is a V6. Although the engines sound lovely and are a blast to drive, the 75 V6 option was discarded.
So what then? I've always had an interested in force fed, mainly turbocharged engines. Modifying an engine for fitting a turbocharger isn't cheap either but it promises a good power increase accompanied by a fat torque band. Savali Tuning offered a turbosystem made by Novitec in Germany for the TwinSpark engine, delivering 200 hp. Now that sounded interesting. The only problem was that it was only available for the new 16V engines. After gathering quite a library on turbocharging a petrol engine I decided to give it a go myself.
In april 1998 I put the car in the garage and pulled out the engine. By that time I came into contact with Jim Steck of Autocomponenti. Jim is quite an expert in turbocharging Alfa engines. He sent me to his webpage and gave some good advices of do's and don'ts.
Work started on the engine. After disassembling the engine I found it in perfect condition. The weak performance could only have been caused by a vacuum leak. It turned out to be the brake booster. However it was already to late: turbocharged it would be! After some pain staking adventures involving broken headstuds (for milling the block itself they had to be taken out) things started to point in the right direction. The broken stud had been removed and extra oil passages for main bearings #2 and #4 were drilled.
Half December 1998 I went to my garage and found out that a friend of mine crashed his 75 3.0 V6 earlier that morning. It took some time of trying to fix the car to find out that it really had been bent in the crash. My friend wanted to get rid of the wreckage and we made a deal. So now there was a complete V6 engine with all the necessary parts to make it work. The TwinSpark engine had to go.
While dismantling the V6 it became obvious that apart from the rings, oilpump and valve guides it was in quite good shape. From the previous owner I knew that once a piston had melted but there were no traces left of it. I cracked the crankshaft pulley while I tried to get it off the crank. Eventually it did and I started to look for a pulley that was still in one piece. I found one via Usato, the local Alfa shop. They knew someone with a 2.0 V6 (imported from Italy). The pulleys of the engines do match apart from the balance, but this was no problem as the crank group had to be balanced anyway. I also bought the oilpump which was in excellent shape despite the oil itself being mud.
After a lot of grinding I took the crank, pistons and flywheels (transaxle also) to Bob van der Zijden engineering. He lost a lot of weight on the flywheels, enlarged the piston eyebrows and balanced the whole crank group and transaxle flywheel. In the mean time I ported the heads and had the new modified valve guides put in.
Since July 1999 the car is gray again. It took a long time for the camshafts to arrive but they did eventually in October 1999. The copper headgaskets could not be fitted because of sealing problems with the o-rings (Too much force would be necessary to seal them). I switched back to the stock gaskets and it cured the problem. The downside ofcourse was the raise in CR, compared to the Cu-gaskets being thicker.
I finished the engine in november 1999. It was built normally aspirated at first for inspection by the Dutch vehicle authorities. When I fired it up for the first time it ran horrible and only high revs. Advancing the ignition did wonders. Another problem was the extreme HC emission. The 4 gas analyser tilted with the probe in the tail pipe. Fouling racing plugs seemed to be the cause. They need lots of heat to clean up which isn't available at idle. The mixture being a little on the rich side and the increased valve overlap of the cams didn't make it better either. Fooling around with lambda probes, AFM springs, fuel pressure regulators (the injectors tend to stream rather then spray at stock pressure, a modest increase in pressure makes them spray better) and spark plug grades showed some improvement.
November 25 1999 was THE day. The car had to be checked by the vehicle authorities since it no longer had 4 cylinders. In order to make it street legal again there should be 6 cylinders and the engine number in the papers that come along with it. The RDW in Holland is the only instance allowed to approve modifications made to a vehicle and since they are the only instance I had heard some pretty freakin' stories about them. So with the HC emission in the back of my mind I went to them with my heart in my throat...
At the check point it was their last job of the day and the two other mechanics came to take a look. I wasn't too pleased with it, because three pairs of eyes see more than one. At the snif test the engine would barely idle, it was that lean. The drive to the check point had certainly cleaned up the racing plugs as they still tend to faul on warming up. The result was a very low CO rate which was excellent according to the chief mechanic. Yeah, you're right and I'm Santa Claus! Anyway everything checked out fine and the car is now an offical 3.0 V6.
At the end of Januari 2000 I went back to my calculator and archives. If Audi can build a high CR V6 turbo, I can perform the same trick. Things started to go fast in februari with the construction of the apropriate set of exhaust manifolds. New flanges and some modifications of the tubes made it possible to mate the V6 and the Garrett hair dryers. Additional plumbing of the oil and coolant feeds cleared the way for a first though still normally aspirated evaluation (no connection between the turbo's and plenum yet). Turning the ignition key blew me almost on the rear seats. What a noise that was! A howling dragster had been born. The windows of the garage were resonating in their frames.
The project continued with the construction of the exhaust downpipes from the turbo. While waiting for the flanges to arrive I manufactured the tubing system for connecting the turbo's and the plenum. Luckely the intake plenum could be turned round by 180 degrees with the bonnet still closing. The flanges arrived and so did the silicone hose connections. After burning some midnight oil even the stock AFM was connected to the turbo intakes by means of some helicoptre tape. Not beautiful but it worked for the time being. In other words it was ready for a maiden voyage.
The maiden voyage wasn't what I expected of it. The engine would hardly pull and even sucked flat the silicone hoses. Something was wrong. A rag that should keep the AFM from resonating turned out to be sucked into the AFM. No wonder the engine would hardly run. After throwing it away the engine was back in it's F1 state. Jazzing the throttle gave that crisp brutal response again. The ignition timing computer got thrown into a corner. At idle the engine needed a lot more advance and revving with boost it needed far less. A static ignition curve did wonders. The cold racing plugs went in again to prevent a set of holed pistons. After these fixes I went for a second test drive.
What I experienced is hardly to describe. I was complety dazzled by the sheer performance and so intoxating sounds the engine produces. Higher up the gears the true power of the engine is revealed. Third, fourth and fifth gear make little difference. The engine keeps accelerating on and on and with such sheer verocity... Lift the throttle and a big crackling sounds emerge from the exhaust tip: 3 litres of pure violence.
After some test drives the exhaust noise became a little too much to my liking. The straight through exhaust was certainly not street legal. With the windows closed it was bareable but with them opened... The straight through exhaust attracted just a little too much attention. After poking around for a muffler I discovered that 3.5" mufflers aren't for sale at every street corner in Holland. It also had to flow, leaving racing mufflers as only option. The Edelbrock Corporation in the US luckely marketed a straight-through muffler with 3.5 connections, extreme flow and ceramic deafening material that can withstand high temperatures for long time. In other words: perfect.
The exhaust was finished early september 2000 giving a modest noise. It is not too loud but the engine is still sounding capable.
With cold racing plugs engine startup was still a menace. So November 2000 I installed a high power CD ignition system giving up to 50 times more spark power than the stock induction coil. It also allows the spark plugs to be used with electrode gaps of 1.0mm or more. The result is that idle has cleared up and a cold start is possible without waking up any neighbours. Also the car has a much better throttle response and runs much smoother as a bonus.
Added August 12th:
In December 2000 the cams went sour due probably to a manufacturing fault. It took a long time to sort out a pair of new cams but eventually Bob v/d Zijden came up with the idea of making a pair of PVD coated cams. This a very expensive proces resulting in an extremely strong surface layer which is also very wear resistant. However not all cam manufactures stock the same lobe profiles and not every company releases it's detailed profile specs to it's customers. This resulted in the cam company's experts themselves choosing a profile closely matching Bob's modified Colombo Bariani cams.
The 'PVD' cams arrived in early May. High hopes had raised for this truely beautiful manufactured set of cams. It was to be our first PVD coated set of cams, coated with a new PVD material as well. However the cam manufacturer had put on a profile that featured far less lift than the original modified Colombo Bariani's. Timing was a bit longer for compensating the less lift and the exhaust lobes received more lift for benefitting the exhaust gas energy.
When the engine was started it became obvious that the exhaust note was a lot louder. A test drive revealed a vast lack of low down torque (due to less lift/longer timing) and the engine quickly loosing it's power when it reached the normal operating temperature. Traffic lights and traffic jams were absolute lethal to power output. These cams clearly didn't perform like Bob's modified Colombo & Bariani cams.
In the mean time (June 2001) the refreshed Colombo & Bariani cams arrived from the other cam company. These cams feature lobe profiles from Bob's own genius brain and clearly demonstrate his knowledge in cam theory and engine building experience. Twenty years ago he was ahead of his time and he still is nowadays! The CBs were put in the engine again and the result is absolutely breath takening. The engine pulls cleanly from tickover, boost comes in much smoother and is building up far higher than with the 'PVD' cams. It's a real blast to drive the car again.
In July the car attended a session of the weight watchers. The interior got stripped of all sound deafening material. The sound system went out because there are 6 pistons up front to provide the music. Since the rear seats weren't used they were left out as well and all windows were replaced with lexan. So much for comfort.
Work on the ECU has been progressing as well. First runs with the ECU on the test bench in my office showed good results. Hooked up to a 1 meter stack of electronic testing equipment and two PC's, all signals showed up right the way they should. However real life started in the automotive environment. The ignition, alternator and relays all created their fair share of noise to fool the engine management system. Although as an electronics engineer, I was prepared for quite a noisy environment this even caught me by surprise. A month was spent testing and evaluting various filters with good results.
The ECU is real time 3D mappable and also features real time datalogging thus making an excellent engine tuning tool as well. Hooked up to the notebook all signals can be varified and compared and saved for reviewing a later time. It's still work in progress like every software programme.
Added April 21st 2002:
Due to the serious torque the evo1 engine was developing I have been looking into roll cages to beef up the chassis. The handling would benefit from it too. Some time ago we did a 6p OMP roll cage on a friend's car. At that time I made a point that I wanted a fully welded roll cage in my chassis if I ever would install one. Well it happened, I decided to manufacture a roll cage like Autodelta used in the IMSA's. Work started in autumn 2001 with the arrival of a pile of CrMo tubes. The amount of work involved in cutting the tubes, bending them and making them fit was and still is really amazing. At the moment I'm finishing up with making all sorts of support brackets for mounting stuff to it (MAP sensor, the WI pump has moved inboards, and so on...). I'm nearly up to the point where the inside of the car can be painted. Pictures will follow soon.
Added April 13th 2003:
A long time since the last update... with a lot of things happened. The interior got painted dark gray late summer 2002. The interior looked stunning while the paint was wet but when I came back next morning it had dryed up looking horrible! What next? I decided so sand the paint all off and start again and spray paint the interior in the same metalic grey as the outside of the car. With some help I managed to sand the whole interior and prepare it for spraying. We took out the windows and sprayed it on one of the last hot summer days. I was very lucky cuz there was a mild breeze blowing outside to take the spray mist out of the interior. The result is stunning: the interior looks really fab now!
From then on it was putting everything back together. My racing seat went in again,as well as the new carbon fibre battery box and the dash. A real challenge was mounting the fusebox since there were a couple of tubes in the original spot. A hybrid of some sheet metal and part of the original bracket got bolted to the dash in the end. Lots of these silly mounting issues arose and needed solving.
I also noticed that it was kinda hard getting into the car with the roll cage and the steering wheel on the lowered steering column installed. A quick release steering hub quickly solved this minor problem. Since I want to be able to drive the car on public roads as well I needed to solve the horn issue. I found a solution in using a keyboard curled wire. In the steering wheel are also a switches mounted for the launch control and for selecting various mapping settings in the ECU. Without the steering wheel the car won't start either so it is an elegant theft prevention too, should somebody venture into driving the car without steering wheel anyway...
While rebuilding the car I also installed the 2.25" racing springs coil-overs. With the roll cage I no longer had to live with the torsion bars. I now enjoy a really stiff front suspension combined with a softer rear end for traction. I'm really pleased with it.
What happened to the engine? Well, I went back to the trusty four cylinder TS... Just kidding! At first I just wanted to crane in the R&D engine, bold on the turbo's, install the new ECU and see what would happen. However I also wanted to try the high volume oilpump which meant I had to pull the heads. I had to do some engineering to the engine anyway because the waterpump, steering pump and alternator wouldn't fit the chassis anymore due the tubes of the roll cage extensions in the engine bay. The power steering issue was quickly solved by dumping the whole concept. No more power steering. The alternator issue was solved with a really small alternator from some japanese dinky toy. It has internal cooling and still cranks out 60amps, amazing. For the waterpump and alternator I had new alu pulleys made. The waterpump pulley needed to be as large as possible in order to slow it down.
When I pulled the heads I noticed that the engine was in quite good shape. After cleaning the heads, they were the best I had ever seen. After pulling apart a number of engines over the years I have learned that there are serious quality differences in the engine castings. Most of the 12v heads suffer from intake channel defencensies. A lot of heads have too many material taken out around the valve seats. But not this set of heads. So I had a set of superb cylinder heads on my hands. Sure the valve guides were worn out, like they always are on the 12v engines. Why not put in good quality valve guides, port the heads and also use them on the future evo2 engine?
From the cut through head I calculated safe milling drawings (I have had some experiences in the past...) and ported the heads accordingly. All the knowledge I gathered in past years I put into the heads: two real gems were born. No pictures because the recipe is secret. The stock valves are more than good enough for well over 500hp. The valves from the heads looked good and were in tolerance so I reused them after a flow optimising treatment. I used the same Porsche valve guides as in the evo1 engine. This time I kept the exhaust guides as long as possible for wear and left out the seals.
A nice engine was under development. Of course I wanted to use a very light weight flywheel again because I like my engines crisp. I took the crankgroup to Bob vd Zijden and had him balance the crankshaft. Early autumn 2002 I assembled the whole engine and installed the modified alternator and waterpump.
The engine was craned in early November. It fitted beautifully. The dry swimming while welding the roll cage paid off. It would be annoying to have a nice roll cage but not being able to fit the engine, wouldn't it? I decide to go the full Monty and convert the engine to the new ECU as well, mainly necessary due to the faster spinning oilpump. A faster spinning oilpump meant the original distributor would not function at half crank speed anymore. Another solution had to be found for sparking the plugs.
Another point of concern was the cooling system. The evo1 engine proofed the V6 radiator to be too small for serious power figures. After gathering a pile of information on aluminium radiators I found a radiator used in the US NASCAR series to fit my needs. It has a huge dual core, enough to cool down 700hp. Brilliant! After some modification it fitted the chassis like a glove. The stock fan seemed to be designed for the radiator too. It flows more air than all the performance fans I could find. I was amazed to learn that one big fan flows more air than two smaller fans covering a large flow area.
Other stuff that I manufactured included the intake system with idle speed control, the air filter mounts and a light weight custom wiring loom using silver core teflon wiring for the ECU, ignition and WI system.
Back to the sparks. I have been a big fan of the CDI (capacitive discharge ignition) system with it's high energy output and multistrike capability. It allows me to run cold racing plugs without fauling in low strung conditions. Unfortunately the CDI system is for distributor systems only. I found out that in essence there is nothing out there that enables the use of one charge unit with multiple coils. MSD sells a unit for firing multiple coils but the unit is quite large, it draws considerable amps while delivering less energy than I'm used too. I'm a big fan of Motec products but there CDi8 is rediculously expensive and the output is not too much worth writing home about.
Being an electronics engineer a solution to the distributor problem should not be too big of a problem. Figuring out the electronic equivalent of a distributor and using six small coils should solve it. Six coils because DIS aka waste-spark is a stupid system: why first go through the trouble of storing energy in a coil and then throw 40% of it away in the wasted spark? A spark should contain as much energy as possible for a building a good initial flame kernel.
The coil supplied with the CDI kit is superb but quite heavy due to a good but beafy core. Six of these coils would be rediculously heavy and expensive. So I set up a test bench in my lab and started evaluating coils. A lot of time and effort was put into evaluating coils both for capacitive as tradional inductive ignition systems. I learned that large numbers of coils, sold as high performance coils, are in essence crap, with saturation all over the place when using higher current figures. Eventually I found a reasonably cheap Magneti Marelli coil to be of excellent quality and almost as good as the coil supplied with the CDI system. I ordered six of them and manufactured alu brackets for mounting the coils to the engine.
Figuring out the distributor circuit for the CD ignition system turned not so simple as it looked at first glance. Optimizing the circuit for maximum efficiency and dealing with the RFI from the high voltage, high amps (>100amps) proved an arcane task but eventually I found the right formula and the circuit is functioning flawlessly over the entire mil-spec range of -55C to 125C. This is very important because I want the circuit to be reliable and not causing damage to the engine due to wandered off sparks.
Left to do is installing the ECU and kicking the engine back to life.
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Last modified: December 25th 2003
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