Peter Cobbold Posted November 10, 2015 Report Share Posted November 10, 2015 Stuff about vacuum advance and tuning spark and mixture for best mpg at cruise. Involves the interplay between spark timing, mixture, load and rpm. I wrote it to sort my ideas out before building the bits and bobs, but might be useful to TRrers with a light right foot..... https://supertrarged.files.wordpress.com/2015/11/tr6se-34-tuning-for-cruise.pdf Peter Quote Link to post Share on other sites
Nick Jones Posted November 10, 2015 Report Share Posted November 10, 2015 Interesting Peter. You really should get yourself a Megasquirt or similar plus a wide band O2 sensor. Even if you don't want to use it for FI you could use it for ignition only and data monitoring/logging. When I set up my PIe the final stage was at a rolling road (Tipton Garage is highly recommended) and last of all was to play with the cruise ignition settings. The RR was set up to maintain an rpm and with the operator driving the car I sat beside him and adjusted the timing with the laptop. With timing starting at standard distributor numbers we found that the torque would initially increase quite sharply with increased advance, then slow, level off and start to drop again with audible pinking commencing just after the drop off. Settings were left a degree or so before the peak. We picked up 20% torque in places from the standard distributor values. Interestingly enough, the original distributor figures were pretty much bang-on for the WOT condition. That with the original "132" cam, mildly flowed head and 10:1 compression ratio on 95 unleaded. Power @ 148 bhp and 160lb/ft torque and a very flat torque curve. Pulled like a train and averaged >30mpg. Nick Quote Link to post Share on other sites
Peter Cobbold Posted November 10, 2015 Author Report Share Posted November 10, 2015 (edited) Nick, Once its up and running I plan to tune the spark for wot running on a rolling road. Finding optimum spark when the water injection is killing detonation is impossible to guess at: the water dose is fixed so drops with rpm and boost, so its 'boost retard 'effect varies. The cruise tuning does use a wideband UEGO exhaust sensor, and there's electrickery built by a friend to lean the SU under feedback control from the UEGO signal.* I'm told its simple, but electronics passed me by: hence no megasquirt. I should look into a rr for cruise tuning, I had not realised that it was feasible to detect small torque changes on a machine capable of measuring 100s of bhp. I think you have published your efi map, but I cant find it. Could I link to it in the blog post please? Peter *https://supertrarged.wordpress.com/2013/05/06/tr6se-12-electronic-back-suction-control-of-su/ https://supertrarged.wordpress.com/2013/05/03/tr6se-11-cruise-mixture/ Edited November 10, 2015 by Peter Cobbold Quote Link to post Share on other sites
Nick Jones Posted November 11, 2015 Report Share Posted November 11, 2015 http://www.tr-register.co.uk/forums/index.php?/topic/21602-any-one-have-experiance-of-tr6-electronic-fuel-injection/page-2?hl=+electronic%20+fuel%20+injection Vitesse Fuel map and target table are in post 28. I also have ignition maps and the full set for my 2.5PI but I'll have to kick my ancient (car duty) laptop awake for those. Nick Quote Link to post Share on other sites
TorontoTim Posted November 12, 2015 Report Share Posted November 12, 2015 A TR driver with a light right foot? Shurely shome mishtake... Quote Link to post Share on other sites
TriumphV8 Posted November 12, 2015 Report Share Posted November 12, 2015 Interesting to read through the old posts! Nick was an expert already and Tony for example became an expert on the MegaSquirt during the last years...... If people would know about the benefits and how easy it is after being fully understood much more people would try that. Quote Link to post Share on other sites
TriumphV8 Posted November 12, 2015 Report Share Posted November 12, 2015 but electronics passed me by: hence no megasquirt. MegaSquirt can be seen like a tablet or a smartphone. There is electronic and software in a most complicated way inside but we do not see that and we do not need to know details. By the way MegaSquirt can communicate with both items! The difference is that a tablet has an AC Adapter that plugs into the tablet and into the wall at home and a W-Lan that only needs a password but the MS is not that standardized and its connectors to the engine need some brainwork and custom wiring. But that is not electronic, it is electrical wiring we already did several times before at our old cars. Each electric cooling fan or fog lamp needs similar material and work. I bet everybody who uses Windows office especially with EXCEL and already optimized needles on the SU can learn to fully understand the MS software and than set it properly. Quote Link to post Share on other sites
Peter Cobbold Posted November 12, 2015 Author Report Share Posted November 12, 2015 (edited) Andreas, The gulf in my digital knowledge is deep ! - I have never used a tablet or smart phone...my simple mobile phone hardly ever get used....and I've never sent a text.. Mostly its because I dont see the need. But there are other reason why injection is not attactive for my particular project. If an injector partly blocks then I dont just get a misfire, under boost a piston can be destroyed in seconds - silently - by preigntion. The single SU wont do that. And for best fuel effciciency the carb can produce a better mixture with finer droplets than injectors ( unless modern very high pressure common rail is used ). Slide 60: http://www.powershow.com/view/1e2c2-NmY0Z/Chapter_IV_Spark_Ignition_Engines_22703_powerpoint_ppt_presentation Smaller droplets produce a more uniform mixture distribution in the cylider allowing a leaner mixture to burn smoothly on every cycle. The blower's turbulence and heat also helps evaporation so I reckon the mixture is going to run leaner than more conventional fuelling. Its an experiment. Please don't get me wrong, I do like to see different approaches to modifying our engines - including megajolt. Peter Edited November 12, 2015 by Peter Cobbold Quote Link to post Share on other sites
TriumphV8 Posted November 12, 2015 Report Share Posted November 12, 2015 Andreas, The gulf in my digital knowledge is deep ! - I have never used a tablet or smart phone...my simple mobile phone hardly ever get used....and I've never sent a text.. Mostly its because I dont see the need. But there are other reason why injection is not attactive for my particular project. If an injector partly blocks then I dont just get a misfire, under boost a piston can be destroyed in seconds - silently - by preigntion. The single SU wont do that. So I see a good reason to start right here and now....... Lots of people here have a lot of experience with MS & Triumph and would be happy to support the progress I believe. For the SU thing, although I do not see blocking injector, I have a nice idea: You could set the SU very lean and add fuel with a single injector driven by MS after the blower. Additionally you watch the AFR with a LC-2 in the exhaust and correct it with the Megasquirt. For free you get the Megajolt features added and you can be sure with a total failure of the injector the engine will not break. What you can do with a MS2 is to fire a warning light if a defined AFR is too low or high. Like with a big warning lamp for oil pressure you can put it on the dash and after some time when you rely in the MegaSquirt you can take it away or leave it for information. Quote Link to post Share on other sites
Peter Cobbold Posted November 12, 2015 Author Report Share Posted November 12, 2015 Andreas, I plan a big red warning light - for low water pressure ! Above about 4psi boost water will be the only defence against knocking the pistons apart ! At one time I was planning a second jet in the carb, for ethanol - to bring up the octane to around 103RON. But decided the fire risk of a 3 gallon tank was too great. Water feels safer, but there is a power penalty. I looked into a hybrid Lucas PI plus an SU to add extra fuel, triggered by boost. But the injector blockage issue remained. Peter Quote Link to post Share on other sites
TriumphV8 Posted November 12, 2015 Report Share Posted November 12, 2015 Add LPG in the wet phase with MegaSquirt also as a chemical blower and you do not need all that stuff any more. In these days Lucas PI is a bad solutiion because a closed loop with the exhaust gas measurement can not be established. Friend of mine is on turbo trip with modern electronics on a 4 valve intercooler engine and handles 40 psi of boost. Pretty good to bring a 2 litre beyond 300hp. Quote Link to post Share on other sites
Peter Cobbold Posted November 12, 2015 Author Report Share Posted November 12, 2015 (edited) Add LPG in the wet phase with MegaSquirt also as a chemical blower and you do not need all that stuff any more. LPG 109RON ! It would be interesting to see that on a s/c TR. I didn't kown Megasquirt does liquid phase LPG injection. It needs a high pressure pump in the LPG tank to get the pressure high enough to stop it boiling at underbonnet ( ie injector) tempratures. So more complex and expensive than LPG-carburettor. But the evaporative cooling effect- terrific. Edited November 12, 2015 by Peter Cobbold Quote Link to post Share on other sites
TriumphV8 Posted November 12, 2015 Report Share Posted November 12, 2015 Very common in Germany. Friend of mine built several systems. I was involved in one where we swapped a Honda from TBI to a multiport injection with four injectors. Power increased and fuel consumption was in the range of petrol and not 10% higher like often advertised. It worked for 100.000Km and saved a lot of money due to cheap LPG. A little hole is drilled into the manifold and from the injectorbox a small tube like a inner pencil tube is guided into the hole. The injector boxes contain the injector and a jet to limit the flow what is not necessary for Megasquirt because we can set the timing in a wide limit. From the tank in the rear with the inline pump a tube is guided to the rail to the injector boxes. No box of tricks and all easy to build! Quote Link to post Share on other sites
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