Nick davies Posted June 29, 2014 Report Share Posted June 29, 2014 Hi Everyone, I'm new to this forum but have been a TR owner for many years. I'm in the process of converting my TR6 to run Microsquirt EFI. I've got the electrics installed and intend running with the throttle bodies machined to take Bosch injectors and the normal plenum with a Ford throttle body and position sensor grafted on the end; fuel pressure to be controlled with an adjustable regulator. My question concerns the return from the regulator to the tank. The standard return plumbing from the metering unit is 1/8" BSP (I think) so rather small. Being small will it lead to back pressure in the microsquirt system and cause poor pressure regulation? It would be convenient to use the 1/8" piping but does the 1/8" pipework need to be replaced by perhaps 3/8" to overcome any problems? I know that some members on the forum have fitted Megasquirt to their TRs and therefore have experience of these conversions and can advise on any likely difficulties, so I'd be grateful for any recommendations/advice, please. Regards, Nick. Quote Link to post Share on other sites
Peter Cobbold Posted June 29, 2014 Report Share Posted June 29, 2014 Nick, The PI tanks have two return pipes on the top of the tank* - one takes leakage form the MU, the other takes the rejected fuel from the PRV. I suspect if you use say 8mm bore pipe back form your sytem, and then fit a reducing Y to use both tank pipes there may be enough capacity. Worth feeling around the top of the tank- thay are both on the nearside of the filler. Peter * well, mine does! Quote Link to post Share on other sites
saggy Posted June 29, 2014 Report Share Posted June 29, 2014 Hmm, this probably isn't much help but I have another vehicle which is Megasquirted and that uses a 7/16" return to the tank after the PRV. Can I pose another question on this... any views on the correct position for the return to the tank - towards the bottom, middle or top ? ? ? Quote Link to post Share on other sites
GT6M Posted June 29, 2014 Report Share Posted June 29, 2014 (edited) the 5/16 th / 8 mm pipes will suffice for returns.. BUTT, ye need to put the returns thru a filter, then into tank. and try and get the pipe that goes into tank, as farrrrrr away frae the outlet as possible. been there, found all the pit falls, unforeseen probs, and now weel sorted Note, Bigg pipes will lessen frothy return petrol,as it has time to reconstitute itself but a filter is still a good idea I actually ran 15 mm copper pipes as returns when using the B26 pumps but not needed on the small vol / pressure that modern EFI uses but still have the filters in place. m Edited June 29, 2014 by GT6M Quote Link to post Share on other sites
RogerH Posted June 29, 2014 Report Share Posted June 29, 2014 Hi Nick, regarding your return pipe - how small is small? 1/8BSP is 8 or 9mm diameter http://en.wikipedia.org/wiki/British_Standard_Pipe Roger Quote Link to post Share on other sites
Tony Millward Posted June 30, 2014 Report Share Posted June 30, 2014 Nick, 8mm is more thane adequate for a return. We (Ihave EFI too), are using a much lower fuel pressure than the mechanical Lucas system. I have a swirl pot fitted in my boot (trunk), and my return goes into this. I never have the fuel starvation problem when cornering and I don't have a filter on the return as it has been pushed through a filter already and a second one is overkill. Cheers Tony Quote Link to post Share on other sites
Nick davies Posted June 30, 2014 Author Report Share Posted June 30, 2014 Thanks to you all for the replies. From what has been said it looks as though the standard return from the MU will suffice. The addition of a swirl pot is a good idea to remove any foaming from the return fuel. Does anyone have any fuel and ignition settings to use with the Microsquirt. It would certainly make for the eventual start up. Regards, Nick. Quote Link to post Share on other sites
Tony Millward Posted July 1, 2014 Report Share Posted July 1, 2014 Hi Nick, I'm running an MSII (Megasquirt 2) but if my maps will be of any use let me know. Cheers Tony Quote Link to post Share on other sites
Steve P Posted July 1, 2014 Report Share Posted July 1, 2014 Hi Nick, I've recently finished a Microsquirt install. I used the the MU return line for the return from the regulator. Seems to work ok for me. Cheers Steve Quote Link to post Share on other sites
Russell6 Posted July 6, 2014 Report Share Posted July 6, 2014 Hi I have just got back from having my TR set up on a rolling road, which I think is a must when undertaking this type of conversion. Saves the chance of getting it to lean and damaging all your hard work on the engine. The drive back was amazing and money well spent. Like you I have done a two stage drill to accept bosch injectors, enabling the use of the injector plates to hold them in place. I made a stainless fuel rail, and made use of an external fuel pump and filter from an old cavalier SRI, mounted on the outside of the car. I have kept the original fuel filter to act as a small reservoir to keep a constant feed. We had a smooth constant build up of power and a wide rev range of torque delivery. I'm using a canems ECU and wasted spark ignition set up. Looking forward to some European trips Happy motoring Russ Quote Link to post Share on other sites
bluetr6reborn Posted July 16, 2014 Report Share Posted July 16, 2014 well done russ im running efi you wont turn back the power fuel savings every one should do it , mine starts like a modern car fantastic Quote Link to post Share on other sites
Steve P Posted July 16, 2014 Report Share Posted July 16, 2014 Hi Russ, Would you post the HP and torque curves? Thanks Steve Quote Link to post Share on other sites
TriumphV8 Posted October 19, 2014 Report Share Posted October 19, 2014 Question to Microsquirt users: Do you use alpha-n for metering as it has no atmospheric pressure box or did you add it and use speed density? Question to all EFI users: Did anyone get the single throttle body solution work properly together with a wilder cam beyond 280 degrees? Quote Link to post Share on other sites
Tony Millward Posted October 19, 2014 Report Share Posted October 19, 2014 Question to Microsquirt users: Do you use alpha-n for metering as it has no atmospheric pressure box or did you add it and use speed density? Question to all EFI users: Did anyone get the single throttle body solution work properly together with a wilder cam beyond 280 degrees? Hi Andreas, Initially, I used a single throttle body and it worked quite well. I then changed to individual butterflies (using the original throttle bodies), and noticed a vast improvement in acceleration and drive-ability. I have separate air filters on each pair of bodies and an air feed to the filter area. I have now made this permanent as it gives the oomph I wanted...and it seems easier to tune for some reason. I also use 'Speed density' and my setup maps are available to anyone. Cheers Tony Quote Link to post Share on other sites
TriumphV8 Posted October 21, 2014 Report Share Posted October 21, 2014 Interesting to read Tony. I was convinced to use six butterflies but could not compare both versions. What I can add is the swap from stock cam > 280 > 290 degrees what was together with the manifold design each step a good choice. Cheers Andreas Quote Link to post Share on other sites
Tony Millward Posted October 21, 2014 Report Share Posted October 21, 2014 One of the biggest challenges in using a cam with a large overlap is that not a lot of vacuum is produced. This affects the MAP sensor (not to mention the brake servo), which tends to fluctuate which in turn affects the settings. I got over this by fitting an alternator from a 4 wheel drive car which has a vacuum pump fitted. This was connected to my brake servo and I now have good, constant brakes. I also made up a breathing system for the engine which maintains a negative pressure in the engine and has virtually eliminated oil leaks. The only slight leak I have on the car now is from the gear selector rod o rings...not a good design unfortunately but I'm working on that. cheers Tony Quote Link to post Share on other sites
TriumphV8 Posted October 21, 2014 Report Share Posted October 21, 2014 Half way round the planet and same solutions! I use the vacuum pump from Opel Corsa Diesel easy and cheap to get here. Cheers Andreas Quote Link to post Share on other sites
Steve P Posted October 21, 2014 Report Share Posted October 21, 2014 Hi Tony, Did you use the original inlets or did you go for a nice bespoke manifold? Steve Quote Link to post Share on other sites
Tony Millward Posted October 22, 2014 Report Share Posted October 22, 2014 Hi Steve, I used the original throttle bodies but designed and made my own throttle linkage...smooth as silk. Cheers Tony Quote Link to post Share on other sites
Steve P Posted October 22, 2014 Report Share Posted October 22, 2014 Tony, Do you have a photo? So I guess the MAP is atmospheric pressure? Thanks Steve Quote Link to post Share on other sites
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