Megasquirting a 3.9 RV8

cammmy · Post by **cammmy** » Sun Jun 12, 2011 11:35 pm

Hey Guys

I'm getting a 3.9 RV8 motor which I am looking to supercharge. I'm looking at using megasquirt for the EMS and would like some advice on choosing the correct components.

I'm thinking that I would like to use batch fire injection with wasted spark using the MS inbuilt MAP sensor (possibly with barometric correction from startup)

Would the below parts be a good place to start?

MSII (with MS Extra update for wasted spark)
2x IGN-4 Four-Tower Coil Pack with BIP373 ignition modules
MS Relay board (http://www.diyautotune.com/catalog/mega ... -p-32.html)
Wiring bundle (http://www.diyautotune.com/catalog/mega ... p-101.html)
Relay cable (http://www.diyautotune.com/catalog/mega ... -p-47.html)

Also thinking about a wideband in the collector and was reading about using EGT probes on the runners to make sure some cylinders are not running lean (which is cheaper than running a wideband on each runner). Would it require sequential injection to trim them individually? I'm guessing with batch fire you have to tune it to the leanest cylinder (although having the injectors mounted right before the port should reduce issues with some cylinders running a lot more lean than others?)

What trigger/s does the standard EFI system use on these motors? What would I be looking at doing to enable the ECU to run wasted spark? I'm assuming another trigger wheel will need to be added?

Cheers
Cam

DaveEFI · Post by **DaveEFI** » Mon Jun 13, 2011 8:03 am

3.9 engines usually have distributor ignition, so the tach feed to the EFI comes from the coil. The usual way if dispensing with the dizzy and going wasted spark is to fit a trigger wheel to the crank pulley. Several do kits for this, using a Ford VR sensor.

I'd contact ExtraEFI with your requirements as they are the UK experts for all the options, and have extensive knowledge of the RV8.

If you have decent wiring skills (you'll need them anyway even if making up your own loom from generic bundles), it would be cheaper to start with an RV8 EFI loom and modify that. It already includes a main and pump relay.
I'd also keep the EFI and ignition looms as separate as possible. A hotwire loom is the best starting point as it uses thinwall cable, and the insulation on that doesn't seem to harden at the ends as much as the earlier stuff.

daxtojeiro · Post by **daxtojeiro** » Tue Jun 14, 2011 7:47 pm

Hi,
as Dave says, Id see www.ExtraEFI.co.uk for your enquiry

Youll need a 36-1 crank wheel (or similar) to run wasted spark on an RV8, you don't need a relay board (waste of money TBH and yet another connector that can fail)

Have a look here for more info on V8 complete packages: http://www.extraefi.co.uk/RV8_Kits.html#wasted

Theres even Plug-n-Play options for the RV8 http://www.extraefi.co.uk/RV8_Kits.html#pnp

In order to tune each cylinder using EGTs you will need to run full sequential fuel, this would need a cam sensor as well as a crank signal. Youd also need an MS3 to achieve that on an 8cy engine (MS2 can run up to a 4 in seq)
Have a read here for more on seq and EGT tuning:
http://www.extraefi.co.uk/Seq_MS3.html

Phil

cammmy · Post by **cammmy** » Tue Jun 14, 2011 9:13 pm

Thanks guys, I'll check those places out.

The reason I'm looking at the relay board is because It's going into a TC2500 which is carb'd. I should be able to get the standard loom too though so hopefully that will help if it has the relays I need.

It's from this era of disco so not sure if it's flapper or hot-wire:

Okay, I'll forget about EGT tuning

cammmy · Post by **cammmy** » Mon Jun 20, 2011 12:30 am

I have a dizzy with a lumenition (or similar, can't really remember the brand) ignition module.

I might setup the MS to run fuel only and once all that is sorted and tested, move to wasted spark. Should simplify getting the car up and running?

ChrisJC · Post by **ChrisJC** » Mon Jun 20, 2011 6:53 am

cammmy wrote:
It's from this era of disco so not sure if it's flapper or hot-wire:

Okay, I'll forget about EGT tuning

If it's from that era of Disco, then I think it might be GEMS or Thor, i.e. distributorless. Is it definitely 3.9?, or is it actually 4.0 (I realise they are the same, but the distributor engines were called 3.9 and the distributorless engines 4.0)

Chris.

DaveEFI · Post by **DaveEFI** » Mon Jun 20, 2011 8:18 am

cammmy wrote:I have a dizzy with a lumenition (or similar, can't really remember the brand) ignition module.

I might setup the MS to run fuel only and once all that is sorted and tested, move to wasted spark. Should simplify getting the car up and running?

That's how I did it - less things to learn all at once if you do it in stages. However you could make up or modify your loom with EDIS or whatever in mind to save having to do this twice. All that means is an extra wire in the MS loom - EDIS needs two connections, a dizzy only one. If you go for EDIS, that loom can be separate.
As regards flapper or hotwire, makes no difference to MS as you'd normally junk the flapper or hotwire unit - although you could use the hotwire unit if you decided to. But iit would be better to use hotwire hardware as your basis if you have a choice.

cammmy · Post by **cammmy** » Tue Jun 21, 2011 1:22 am

It's definitely a 3.9. I may have been mistaken with the picture. Looks similar but could be earlier I guess.

I'll be using the inbuilt map sensor or maybe a speed density/AlphaN hybrid system depending on complexity. I won't be using EDIS as I don't believe I will need to. MS can control coil drivers.

The loom idea sounds like a good one. I'll keep it in mind.

Cheers

cammmy · Post by **cammmy** » Mon Jun 27, 2011 3:39 am

Got the computer and loom with the motor. It's a 14CUX so I'm guessing it's not really of any use to me as it doesn't control spark?

cammmy · Post by **cammmy** » Tue Jun 28, 2011 9:21 am

When going wasted spark on a V8. Will I need to use 2 x4 output coil packs or 4x 2 output coilpacks?

SimpleSimon · Post by **SimpleSimon** » Tue Jun 28, 2011 1:13 pm

2 X 4 unless you use the Range Rover 8 coil pack

ChrisJC · Post by **ChrisJC** » Tue Jun 28, 2011 3:02 pm

cammmy wrote:Got the computer and loom with the motor. It's a 14CUX so I'm guessing it's not really of any use to me as it doesn't control spark?

Correct. Well, you could add to the loom I suppose.

Chris.

ChrisJC · Post by **ChrisJC** » Tue Jun 28, 2011 3:03 pm

cammmy wrote:When going wasted spark on a V8. Will I need to use 2 x4 output coil packs or 4x 2 output coilpacks?

I'm not sure it matters. I think that the Thor engines use 2x 4output packs, and the GEMS engines use 4x 2output packs.

Chris.

cammmy · Post by **cammmy** » Tue Jun 28, 2011 7:45 pm

Awesome, thanks.

I was wondering as I have read you need to be quite careful with wasted spark on a supercharged setup as there is a risk of backfire up the inlet.

cammmy · Post by **cammmy** » Sun Jul 17, 2011 10:50 pm

The extra EFI kit has 2x 4 output coils and uses an MSII with Extra code so I think this parts list is still suitable. Will just need a good release valve in case of back fire.

MSII - $266.00 - $313 NZD
http://www.diyautotune.com/catalog/mega ... p-119.html

IGN-4 - $68.50 x2 - $137 - $161.58 NZD
http://www.diyautotune.com/catalog/ign4 ... p-409.html

BIP373 - $8.50 x2 - $17 - $20.05 NZD
http://www.diyautotune.com/catalog/bosc ... p-230.html

MTX-L Wideband - $199 - $235.74 NZD
http://www.diyautotune.com/catalog/inno ... p-467.html

Wiring Bundle - 12' - $46 - $54.26 NZD
http://www.diyautotune.com/catalog/mega ... p-101.html

Will still need to sort fuel pump and sensor but I think that's the gist of it.

Just need to get my Peugeot build done then I can start on this