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Not too worried about fuel, as it is only used for trialling once a month, doing it to see if I can Thanks for the responses. Found a bit more info, it's a DPR/sprintex charger conversion by DPR/Mr Six. Again still don't know what the internals have had done to them, if anything. The motor in the trialler is currently a 3.9 with MS, the plan will be to swap the MS onto the new engine, including the 3.9 Hotwire injectors, fuel rail, etc etc.(I've had problems with flapper resistor packs previously). So good to know the standard injector/pump set up will work. Haven't seen the engine yet (but too good a deal to turn down) but it includes an auto box and Tx box. I am most concerned about the spark issue and think i'll have to do some research to find a sensible mild base map, currently the 3.9 is as aggressive as I think you can go with a standard engine, can't hear any pre ignition, but at full bore with the exhaust outlet under my bum I can barely hear myself think! Thankfully the 2.5 bar sensor should be ok, but having read the thread listed will need to look a brakes, unless the engine has the bits needed (or could I move the Vac tubes to the inlet side of the blower?) Are there any other people running this type of set up who'd be prepared to send over a safe(ish) base map/tune? From most comments the standard MS can handle the levels of boost that I'll be looking at.

After significant time away from playing with megasquirt (it's all been working fine, thanks to all on here, no pinking popping or vac advance problems) I've now purchased a 3.5 v8 with a sprintex supercharger currently fitted with a flapper system. The engine is a known runner, and cam from and overfinch fettled RRC. Various internal components are unknown parts, it was built by a known drag race engine builder and I am currently looking into the history to find what has been done. Aside from my wifes disappointment with me for grinning like a school boy when I told her, how much difference will there be in the fuel and ignition maps when I have the squirt fitted? Are there any additional componentry to fit? Will the standard hotwire injectors and EFI pump support the fueling requirements? Hoping to fit over the summer trialling season break but want to be as prepared as possible before hand to avoid too much head scratching.

I seem to be having problems uploading screenshots since changing to Linux, not sure why.... 5 mins of thought and realised that it's not the software, its the idiot operating it...

Time for an update... Few trials now and a few more mods to the map. The engine is running much better, no lag, good pickup and plenty of power. A bit more reading mainly "how to tune your V8" type books and have now wound the advance at idle up to 10 degrees, upped the valley to 2 degrees (definate improvement when the fans auto start, not megasquirt controlled, yet.) whilst keeping the maximum advance the same. As well as having the fuel cut on overrun I thought i'd retard the ignition in this region as well (only sat here this evening I've realised that this does nothing!!) Seems to have sorted most of the issues i've had with it. Next step is to build an extension loom to get everything waterproof for logging in winter in cumbria in a windowless trials vehicle....

I have to conceed that i may err on the side of caution when it comes to soldering and modding the internals, but now i may have to take up the challenge and go for it... Badders, if you go down the in-line thermoswitch route, I'm running an 81 degree thermostat with a 92 on 86 off switch, this seems to give a good balance. I know the engine is getting full coolant flow before the fans kick in, I boiled the thermostat in a pan with a sugar thermometer and it was fully open around 85 degrees. Not totally familiar with the THOR layout or which thermostat you have, but would it be possible with a switch that low you may never get full coolant flow in the engine?

Just a thought, would it be easier, simpler and possibly cheaper to find a thermostat housing with the switch boss? Seems like a lot of risk fiddlig witht the guts of MS and modding the board if your not 100% confident with the level of soldering. Having had to replace components during my build and then subsequently repairing the damage I caused, i wouldn't risk it agin unless it was absolutely critical. [or am I not getting into the spirit of megasquirt?] I thought about it and went down the thermostat housing route with my trialler as it allowed me to leave a manual overide in place without any risk of affecting the megasquirt. The fan switches are widely available, wiring is simple and risk is negligible. Just a thought...

Fridge Freezer, I thought a sensible approach would be a 'performance' dist based map, as this would give a characteristic that would be safe for the engine. Working on the principle that any of us could go out and buy one and bolt it on. To be honest until i'd looked into the ignition mapping i wasnt aware of the amount of damage that could occur with it being too advanced, one of the reasons i've stuck with a known working map prior to starting this process. It has been an eye opener and one hell of a learning curve, I bought the kit second hand but unused from ebay, plus a few bits from Nigel. Since throwing all the parts into the engine bay I've had capacitor failures, resistor failures and have had to replace the injector controller dual inverter chip thingy. That was a few weeks of head scratching, turns out that age and not being used had not done the components on the board any favours, but thats probably a topic for a different thread . The support and resources available on the forum have been useful and can provide good starting points and i thought i'd put this together to bring all the various questions on ignition mapping and starting out as a bit of a how to, it remains to be seen if this works in the field or quarry. To be honest I didn't think i'd find myself line checking the PCB to diagnose an integrated circuit failures in order to get the injectors to fire on a 25+ year old engine!! I would do it again tomorrow, as i have learnt so much in the last 18 months on engine management. Hopefully Santa will bring me a wideband sensor kit and then it'll be research into AFR tables and all the other good stuff associated with that

OK, i'm fairly new to this but have recently been looking at timing issues with my own, I've a couple of questions as I'm not totally familiar with your set-up: Is the VR sensor reading off the fly-wheel teeth? Have you tried (from the initial post) +20 degrees in the trim? From your description and looking at mine, if i went to 7 teeth that would put my missing tooth 20 degrees BTDC, hence the +20 How many teeth on your wheel ( would allow how many degrees per tooth and a refinement of the trim angle). This may sound simplistic, but sometimes the simple mistakes can muck it up for weeks. Good luck with it...

Hello, This is my first post on here so please be gentle and admins, by all means move delete as appropriate. Like a lot of people starting with megasquirt I've been through Nigels (HFH's) comprehensive posting as req'd to try and get round various issues. Having finally got my 3.9 started and running with base maps (again provided by Nigel) and the installation effectively 'finished' i've been having the following issues whilst trialling: 1. Flat at WOT and feeling bogged down in the middle rpms 2. Lag from idle before picking up revs 3. Significant lag at idle and throttle is blipped (almost an impulse step) 4. Slow response to regain revs when starting large electrical loads (fans) I spoke to a mechanic friend of mine and his opinion was a lack of advance in the ignition (issue 1) and a poor ignition map for the others. Initial test was to up the trim angle to force in more advance across the range, not a very refined method i'll admit, but results sat in the garage was an instant improvement in response whilst up to temperature (away from dreaded zone of warm up enrichment). So with the evidence of my ears and a small amount of knowledge (dangerous i know) I set out to re-write a starting point map that would work, and yet remain safe and not damage the engine. So my brief had 4 requirements: 1. Find a way of modelling a known distibutor, but not a lucas if possible. 2. Generate a new table that would be "safe" 3. Be able to model both vacuum and mechanical advance. 4. Manually adjust to put a "Valley" outside the bottom of my known rev range to assist in stablising the idle The starting point was to try and find a generator that would allow me to understand what it was generating and how it was doing it, and allow me to model a known working solution within the 12x12 map. As a mechanical engineer I decided it was easier to use someone elses solution and reverse engineer understanding than make my own. Luckily after a few hours of searching i came across this thread on another forum: http://www.msextra.com/forums/viewtopic.php?f=94&t=29033 which contained the following spreadsheet (of unknown origin i'll admit please do not follow if you are concerned about the security implications of unknown excel spreadsheets): http://home.comcast.net/~whaussmann/MS_MGBGT/MGB_Ignition_map.xls This will generate a table based on both a vacuum advance and up to 2 spring rates for mechanical advance (not quite as refined as a 12x12 table, but please remember I am trying to create something that works and refine in the future). This allows the modelling of a magnecor type dual spring distributor with vacuum (fulfilling the requirement of a "known" solution). This can then produce a mechanical response (advance) that will look something like the two stage graphs at the bottom of the following link. This can be adjusted to fulfil what appears to be a fairly standard "bring in quite a lot of advance early" approach (the spreadsheet can only do linear response, but you could manually input figures to give a more refined match): http://www.britishv8.org/Articles/Curving-Rover-Dizzy.htm So as a compromise between the various curves i chose to have the initial spring coming in between 900 and 1700 rpm with an advance of 15 degrees and the second spring operating from 1800 to 3300 rpm with a advance of 10 degrees. This gives a total of 25 degrees of mechanical advance across the rev range with it all in by 3300 rpm. The next challenge was to find the characteristics of a vacuum system that would work on this engine, a few more hours and another tank of juice on the e-cigarette yielded: http://www.distributordoctor.com/vacuum_units.html This gave me the data needed to produce a vacuum response of 5 inHg start 17inHg with a total vacuum advance of 8 degrees across the range. The final stage was to input the static advance, the book says 2-3 degrees for a 3.9 high compression, so I used 6, as it looks better at 0 vacuum and i can adjust as required. Once the table had been generated i adjusted the 500rpm bin to be 800rpm bin +1 degree, uploaded to the ecu. The result, a stable idle at 750rpm and 35-40 kPa, no lag on revving and a big grin in anticipation of the next competion. Having looked around this forum, I have concerns about this as it appears to have a lot of advance, similar in areas to Nige's 'extreme' tables. However, having looked into the theory I think this is quite an accurate modelling of a magnecor distibutor (with the advance limited towards the top end) fitted with a Lucas vacuum advance module (admittedly one for an MGBGT) and represents what would be happening on a dizzy driven ignition system. Hopefully someone may find this useful. Comments please...