Jump to content

MegaSquirt on my Opel Manta ex-SD1 V8 engine, success story


Recommended Posts

Thought I'd add my success story here, albeit not an LR4x4 but has the benefit of this forum - thanks to Nigel and the wealth of information from many contributors on this forum.

I've got an Opel Manta (GT/E) coupe that was built by a previous owner as a rally car for tarmac stage rallying, with a Rover V8 engine fitted into it.

The donor for that engine would have been the Rover SD1 3500, single plenum 'flapper' Lucas injection system, distributor, etc.

Although it worked fairly well, the engine was exhibiting common failings that arise with that factory setup over time:

* Poor idle control, especially hot or when electric fan kicks in

* Flat spots, worst when using wide-open throttle from low revs; engine would bog down a lot before chucking the car up the road

* Misfiring some of the time; hard to pin down the cause even when new coil, plugs and other parts changed

Rather than continuing to replace various parts, chasing common problems, I went for the recommendation of fitting MegaSquirt engine management. I bought a full kit of parts from HFH at http://www.megasquirt-v8.co.uk/ms_3-5_etc.php, including new top-end parts to replace 'flapper' injection components with later 'hotwire' manifold, plenum and parts, as well as trigger wheel, sensor, EDIS-8 and Ford coil packs, and an MS1 ECU pre-loaded with an MSQ map for a standard 3.5 litre RV8 engine.

A few differences found along the way where the Rover V8 injection differs slightly between the SD1 saloon and the Range Rover 'Classic' 3.5 v-belt engine but nothing insurmountable. For reference, these differences are:

* Injectors; the nose on the bottom of the SD1 injector is of a different size and design to other RV8 injectors - use injectors from the hotwire, or later, setup

* Fuel pressure regulator; there are a number of different fuel rails, use whatever seems suitable for your own installation

* Crankshaft pulley; there are less parts on the SD1 crankshaft pulley - I do not have power steering so even easier to remove unwanted pulley and fit the trigger wheel

* Crank sensor mount; as the crankshaft pulley differs, the bracket provided in the Megasquirt-V8 kit does not put the sensor in line with the trigger wheel - easy enough to space out differently or create a new bracket

* Heater matrix feed pipe; on SD1 it is from a pipe at back of the thermostat housing, below the inlet manifold - on the other V8s, from some other pipework (don't yet know where but will probably use manifold heater supply when I eventually plumb in my heater)

* Heater matrix return pipe; on SD1 it goes below the inlet manifold, not present on the RR manifold but can be bolted in place with original SD1 pipe and hose

Pleased to say that the conversion from flapper to hotwire injection parts was basically easy enough, and that the MegaSquirt setup worked straight off, as per Nigel's instructions.

Now, the engine starts reliably whether hot or cold, full throttle is usable from minimal revs, no misfiring evident at all and the engine seems much happier to shoot through the rev range. I still need to do some fine tuning and a before-and-after rolling road power run for comparison purposes to get an idea of how different the power curves, and peaks, may be as a result of the upgrade.

I do have a few other things to do for the installation, hence occasional questions to be posted in here.

Hope you don't mind the non-LR input :-)

Link to comment
Share on other sites

Dont mind at all. Anything a little different will be welcomed round here ;)

My dad has a capri with a 4.6 RV8 fitted. Although it hasnt been squirted yet, you can imagine how it goes. Especially with a 2.0 axle fitted... She spins up the rear wheels in 3rd when pushing hard - even in the dry!

Link to comment
Share on other sites

  • 1 year later...

Bit of an update. Had done various mods to the car as a result of ralling exploits (suspension, brakes, pedal box, rust repairs, more rust repairs, wheels, tyres, more tyres, headlamp repairs, other panelwork repairs, cooling pipework, sump guard, wiring, lsd, valley gasket)

As for engine management, had mostly left that alone as it was working ok.

I did dial in some offset for the timing wheel trigger as tdc didn't quite match. I may still be off a degree so I should check it closer again. Doesn't seem to pink so not feeling at risk of damaging the engine anyway. Also put in one of Nige's t-stat restrictor plates as car was running with no stat. It does now appear to run cooler than it did without that plate in there, so must have affected flow around the top of the engine.

I had done a rolling road session on the SD1 flapper-based setup, showing dips, spikes and wobbly lines galore.


Got around to a further session last week with the MegaSquirt installation, running near-enough standard Nigel map settings.

Power/torque curves look much happier now, although dip with WOT at low revs would benefit from filling in.


Outright power is probably not what I would hope for, though given lack of fine tuning of mapping values, seems fair enough so far.

It also sounded pretty good on the rollers :D


Link to comment
Share on other sites

  • 3 months later...

Unfortunately my last rally ended with a head-on impact to a giant wet straw bale, following brake failure :-o

Car didn't look too happy about it afterwards





Removing the broken radiator, oil cooler, water pump, alternator, timing cover, oil filter and other now-scrap parts leaves it looking like this




More to be removed, needing new whole nose cone to be grafted on, replacement inner wing and chassis rail end, plus bonnet, wings, bumper and headlamps.

The engine also coming out as it had poor compression on one cylinder before the event, despite running quite nicely, as I don't know if it sustained any further damage besides the front-end alloy parts being smashed - it may have run a while as it threw out all its oil. So I have a replacement engine on the way, onto which I'll put my manifold and megasquirt injection plus coil packs and dumpy dizzy. Have already sourced SD1 front cover, alternator bracket and water pump to go on there.

Will quite likely take this opportunity to make some changes to routing of MS wiring, also putting ECU in a different location in the car as heater gubbins all being removed as part of this work (it wasn't connected anyway) and dash wiring to get a revamp too to use more circuit breakers and individual circuits.


Not sure when that will all get done as it involves time and money, neither of which are exactly easy to get and to throw at the car...


Edited by rutthenut
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Create New...

Important Information

We use cookies to ensure you get the best experience. By using our website you agree to our Cookie Policy