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Old School Six


Bruce Tollan1436215447
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I'm thinking of converting an old ('73) 2.5 Triumph PI to electronic injection, currently lucas mechanical injection. questions are; what injectors, MAF or MAP, O2, Ignition should I go for? is Cold Start required. My preference is decent quality, easily obtainable and reasonable price. what link unit is best suited? No turbo or supercharger required. max head flow with work would be Less than 100 CFM (best standard heads flow at 70 - 80 CFM) I don't expect a rocket ship but looking for decent power and reliability on a fast road cam. something around 150 BHP would do. A '73 2.5 PI had an awesome 125 Hp from the factory and TR5's and early TR6's 150. The clever blokes at leyland detuned them with milder cams after that so they could meet US emission standards. For the young fella's, think of these engines as the grandfather to the RB20's Rb25's (The 2500 is a stroked 2000 engine) Any advice or piss take is welcomed Old School Rules

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There are heaps of sites on the web that will help you calculate the required injector flow rate.  Once you have done that you will be able to find an engine that had that flow rate injector.  As you are only going for lower power, finding injectors in that size range will be easy.  If you use an LEM G3, you wont need a MAF meter.  I would recommend doing it this way for the best compromise on cost, performance and driveability:

  1. Use an LEM G3 as it is cheaper than the LinkPlus G3.

  2. Use a holden 6 cyl dual post coil pack so you can run wasted spark (distributorless ignition).  Old distributors just result in unstable timing and poor spark energy...  You will need a three channel ignitor.

  3. Fit a 36-2 toothed wheel to the crank pulley.
  4. Fit a bosch 2 wire ISC valve so you have good idle speed control.
  5. Use a innovate LC1 wideband O2 sensor if you plan to tune yourself or a three wire narrow band O2 if you just want it for economy while you are driving.

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We are working on our own "approved design" at the moment as we have had too much trouble with all the home made ones.  Believe it or not it is important to have the correct shaping of the teeth and gap to ensure a stable signal...  We should be able to supply them in the very near future.  They will be a blank wheel with the teeth cut and a pilot hole in the centre.   How soon do you need one?

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Can't see me getting stuck in to fitting any thing for at least a month and I'll probably start on fuel supply issues first and that will take a while with fabrication and things. I'm in engineering design (3D Solidworks) and deal with Laser cutters regular so it would not be a problem for me to get wheels cut if it helps in any way. contacted my mate at Holden Parts Haven here in Hamilton and he has the Coils off a V6 with the ignitors attached, Idle control Valve and Injectors that I need to check for flow rate. I can also get the looms with the plugs, is this the best approach or is there another option for wiring them back to the ECU?

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The ECU will come with a 2.5m breakout loom.  You will need connectors for the injectors (we can supply some types) and idle valves so usually end up attaching to factory wiring about 6-10 inches back from the part.  We have an engineer drawing up the parts in solidworks for cutting at the moment so when you need one let us know.  I don't imagine they will be too expensive...

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  • 2 weeks later...

All you need is a coolant temp sensor (100% necessary for any engine management system).  You need all of the following stuff which we can supply:

  1. Coolant Temp Sensor (100% necessary)

  2. Throttle Position Sensor (100% necessary)
  3. Intake Temp Sensor for IAT compensation (not 100% necessary but recommended)
  4. Oxygen Sensor for closed loop lambda (not 100% necessary but recommended)
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  • 3 months later...

We now have 3 types of trigger wheel. one with 58 teeth and a gap of 2 teeth which is 200mm diameter. This is good for lower speed applications <8000rpm.  The other two wheels have 24 teeth of which you can remove a tooth if you require a sync. They are 150mm or 175mm diameter. We should also have a matching sensor shortly. But if an option is need sooner a Subaru reluctor sensor can be used.

Simon

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You have now confused me Ashley was recommending a 36-2 wheel a way back. now your offering a 58-2 wheel or 24. can you shed some light on what we're trying to achieve with the toothed gear. I can understand that the ecu needs a signal on which to send a spark and this is supplied by the sensor triggered by the toothed wheel. whats the point of the 'Gap' teeth to provide a sync? Also with this car being a Straight six how important is the number of teeth being divisable by 6? And lastly whats the influence of the number of teeth? is more or less better? I can wait till you guys can supply the bits. I just want some thing that will work up to 6000rpm Bruce

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You need a sync to let the ecu know whereabouts in the 720deg cycle you are at. For wasted spark we fire on both TDC strokes so no cam sync is required.  Any of the 3 options will work for your application its just a case of picking one that matches size wise for mounting.

Simon

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