Mat's F8B - EFI and Turbo Conversion.

[86BOY]

G'day Mighty Boy owners, I recently bought an F6A SOHC Turbo motor, came with ECU, wiring, intake, exhaust manifold etc (minus the turbo). Bought as an unknown condition but I was interested in the manifolds, distributor and what ever else i can use.

Now this motor was in parts and when I had a look over the manifold I saw a completely different intake flange with different mounting holes, I had thought to myself that the F series SOHC motors had the same Exhaust and intakes. At this point i thought I would be putting the whole F6A in and rooting around with engine mounts etc, then I look back on the intake side of the F6A to find an adapter plate attached, which adapts the manifold to the head of the F6/F8.

My question is, has someone seen anything like this and is it a factory adapter? I was really surprised to see something like this. I have seen the Jimny manifold which has the throttle body run above the rocker cover and has a flange pattern just like the standard F8B manifold.

Now I have been wanting to convert my motor to EFI and turbo for a long time now and have gone through a couple of efi threads on the forum.

Before i get too ahead of myself, will this intake be suited for running on the F8B? The thermostat housing seems to be in a good place on the right side and I'll be fabbing up some pipe for the intake and front mount setup. I do plan on an aftermarket ecu to run this setup but would like to hear some opinions on this manifold setup and any trouble I might run into on the way.

I do hope this will work on my F8B but want to find out a little bit more before I buy the turbo for starters. Any knowledge would be much appreciated from those who have converted to EFI (and turbo)

Mathew

[Brayden]

Besides the intercooler, none of what you've pictured looks familiar to me. That manifold seems very tall - almost F8C-ish in design, but for a DOHC. The adaptor plate has me stumped too. Definitely a factory item as it is cast alloy and not machined.

None of that matters if all the parts bolt up to your F8B head - in which case you're good to go.

[86BOY]

Thanks for the reply Brayden. Its got me a little puzzled that's for sure! Didn't realize there were a few F6A variants out there. Yes it bolts up to the head perfectly too but yet to see what clearance there is in relation to a closed bonnet, fingers crossed it fits. I'm mocking all this up on my other MB that has a stock F5A to begin with to see how it all goes. Now the Distributor, its a sideways mounted unit and is not gear driven like a standard up-right distributor. It's a direct bolt up to the head (when the whole standard distributor set up is removed) but the F6A dissy has a male/female end like a G13B dissy. Is the gear on the end of the camshaft (on the F8B/F5A) able to be removed to put the F6A male/female on? On a side note, is the F6A ECU able to run the F8B with a bit more fuel pressure to compensate for the extra cc's? I do plan on an aftermarket ECU later on.

[Brayden]

Just be aware that an F5A block is shorter than F8B, so the bonnet clearance is different.
The distributor gear is press fit onto the camshaft, along with the fuel pump lobe, which must be removed first. A gear puller should get both off.
No reason a SOHC F6A ECU shouldn't run on an F8B - you could either up the fuel pressure or install a piggyback to adjust the fuel mix.

[86BOY]

So I took off the carb and manifold and distributor for a test fit of the goodies to see how it sits and what clearance i have or don't have, and the top of the manifold (AFM plug?) nips the brace on the bonnet

The centre brace has come away from the bonnet skin, causing it to be touching more than it should, so this may be cut away. Hopefully with the F8B being that little bit taller it will still clear the bonnet with the brace removed, fingers crossed.

Other than that there is good clearance every where else, ill be able to keep both top engine supports and the radiator+fan clearance will be good in relation to the sideways mounted distributor.

Next will be to remove the distributor drive gear on the end of the cam and replace with the F6A male/female end, install a new intake gasket and fully mount the intake manifold, have a look at the wiring loom and work out what i don't need from it and then mock up a temporary fuel delivery. Turbo components can wait until i get the setup running.

[86BOY]

Well progress is very slow. Had a look over the wiring loom and thought it would be such a nightmare to work out what wires do what without an F6A ECU pinout. I re-wired my GTI loom for my Sierra and a pinout made this really easy.
Now instead of my original plan of making the F6A ecu run the F8B, I thought going with an aftermarket ECU that actually has instructions would be less hassle and I can wire that in myself. I'm thinking of heading down the Microtech path, being that there are a couple of places near me that deal with that brand.
Is the Snot Rocket still running the LT-10s Brayden? Did you also start with an F6A base map and have it tuned to suit the extra capacity?
Would going with an Ecu like this mean I can remove the sensor on top of the manifold (for the extra clearance) which I believe is the Air Flow Meter?
With a change of ECU plans, ill end up putting the manifold and distributor on my F8B instead of stuffing around mocking it up on the F5A, then ill start sorting out bits for the rest of the EFI conversion.

[Brayden]

Yep, still running the LT10S. Microtech didn't have an F6A map, so it was sent with the map for a 3 cyl Charade (but magnetic CAS), which was enough to get it running.
The LT10S has a built in MAP sensor, but the sensor on the top of your manifold is likely to be an idle solenoid, which you need to raise the idle when the engine is under electrical load. I removed mine and curse my decision. You might be able to move the sensor somewhere more convenient though.

[86BOY]

Great, i'll look into the sensor on top, would be good to relocate it, if not ill remove it in the mean time. Since yours was removed did the idle drop much with the headlights on and other accessories too? My GTI motor has also had the little electric idle up solenoid removed at one point but didn't make a big difference with load on the motor.
I'm also currently talking to Microtech, hopefully I can get something to suit this setup.
When the little gear from the cam is removed, can the one from the F6A be put on any way other than pressing it on? (Heating it up and slipping on maybe?) I didn't want to fiddle around getting the cam out but if that's the only way then that's what i'll do.

[Brayden]

Mine practically stalls when I run the headlights/fan/stereo simultaneously, and that's with a GTi 50A alternator.
I don't think you'd get enough clearance on the cog by heating, but probably worth a shot.

[86BOY]

Yeah i guess bumping the idle up would be the only way to stop it from almost dying, but then it'll be constantly idling high when the motor isn't loaded up as much.
Hopefully the dissy gear will expand just enough to even be tapped on the end of the cam, ill soon find out anyway. If not then the cam is coming out.
Had more clearance after removing the top sensor, even ground down a useless bit of the manifold while i was at it. Did your idle solenoid look anything like this? The top of the sensor doesn't show much info apart from a part number and being 5v.

[Brayden]

That's not any type of idle valve. More likely a MAP sensor.

[86BOY]

Yeah didn't think so myself as it has no moving parts to open a bypass airway or anything, Looks like it can stay off then and let the Microtech take over.

[86BOY]

Back with a small update. Removed all the old gasket from the adapter plate and made up a replacement gasket between that and the manifold. while I was at it, I cleaned up the, injectors, thermostat inlet and throttle body.

I also cut the stock fuel reg off and had a fitting soldered on for an aftermarket FPR setup. I had this done on my GTI fuel rail since the stock one failed.

Next was to upgrade the fuel feed line. Pulled out the Project MB and took the spare tyre holder out, tank out and the line that runs to the charcoal canister. I used 5/16 Aluminium hard line and a fuel pipe bender made it so easy to work with. I replicated the stock canister line and got it pretty well spot on. Ill work out the external fuel pump mount and cut/bend the hard line to suit the position.

Next I decided the cam should come out of the F6A that way I can have someone take the gear off that, have mine removed too and put on in the same position. I didn't want to take it off myself and work out where it should sit in relation to TDC.

I have also started to gather a few more bits and pieces for when I really get stuck into the EFI swap; Mini Radiator, GTI coil + Ignitor and Microtech ECU. Starting to get a bit excited!

Decided I would at least start something on my boy while its still on the road, so i made a mount for my surge tank and mounted it to the back wall in the tray area. I really wanted to have it under the tray but being that room is limited, I couldn't work out a mounting point for it to be upright and defeats the purpose of mounting it sideways so in the tray it went.

EDIT - Images fixed using the forum image attachment. Ps, Photobucket is shit.

[Jellety]

Nice job! Good cleanup with the intake parts, looks sweet!

[86BOY]

Thanks Jellety, a clean up was definitely needed!

So I took the new feed line out and made another one to replace the return line. I thought I might as well have all new lines put in while I'm upgrading the rest of the fuel system.

Also had an idea for the thermo fan switch. I got a fitting to adapt the Mini radiator drain plug outlet to the thread size of the thermo switch.

A few more things are coming along nicely in the tray area, decided to use what I had left of my fuel hard line. I bent up the feed and return lines to the surge tank and the return from the surge to the stock MB tank via the breather using a T piece fitting. Now I need to sort out where ill mount the lift + HP pumps, bolt the new lines in, plumb up the rest of the surge tank lines to the new hard lines and start working in the engine bay.