Just a small update..

I put the smaller R32 turbo back on with the large cam. It still came on too late for my liking, So went back to the standard cam.

I wanted to play with the cam timing, so while the cam sprocket was off, I made it adjustable with 8 extra holes at two degree adjustments.

I first ran the std cam at 8 degrees retarded, 125Nm at 5500, 79Kw at 6900. Then 8 degrees advanced 132Nm at 5100, 74Kw at 5700

So it made more torque with the cam advanced but it fell on its face past 5800.

I understand that an 8 degree change is huge, but I had to starts somewhere. I think a mild cam that is slightly advanced would give good results. I do have a Wade 140 grind here somewhere, I think they are about 136 duration @.050 from memory. Probably worth a try anyway. The big 260@.050 cam was definately too big for the std head and manifold.

I roughly engraved the new dowel holes and the corresponding teeth to be able to change it without too much confusion.

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Any Update on this Simon..?

Kannan

Sikyne, using some of your ideas to try and head down a cheap efi turbo arrangement on the a12.
What size OD tube did you use for turbo manifold?

Hi currently trying to follow this build and do it myself, just wondering with the distributor, i dont have thr stock one, when i brought my 1200 it had a lucas distributor in it, just wondering if all is good to still use?

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Bumping to revive.

Endfab: I'm using 25NB sch40 steam pipe and butt weld fitting if that helps. It's a good match for the exhaust port size which you want to maintain to the turbo inlet, at this point the cross section reduces further to convert the pressure in the exhaust to velocity, which is how the power is extracted in the turbine. You want to avoid any expansions before the turbo as these waste energy.

25NB is 25mm inside diameter? Seems a little small for the A12 exhaust ports which are 27x26 mm

DA70YO u can use any distributor with EFI, in particular the MegaSquirt ECU which Simon is using can use any points distributor as an RPM input

Nb25 is actually a bit bigger than 25mm id. Also,going square to cylindrical you use hydraulic diameter as a rule of thumb. The hydraulic diameter of a 26mm square port is 26mm.

Hi Guys, I don't get on here quite as often as I used to.

I use the smaller NB25 Sch40 tube stated above for my A series turbo manifolds(inc. my race car). I usually split the tube where it welds to the head flange and spread it a little to match the ports and fill the split with weld.
The tube diameter being smaller than the ports helps with the turbine drive energy.

The next pipe size up from this is larger than the ports, and certainly not an upgrade when it comes to all round performance from a turbo manifold.

The Lucus distributor is fine to do the mod to, but the allthread has to be mounted a little lower (where the widest part curves under) to get a solid thread into the distributor body for the sensor mount. The trigger wheel has to be mounted lower to line up with the lower mounted sensor. I have done a Lucas unit and it looked quite good as I could machine a lot of the top of the dist body (down to the bottom of the original Vac advance hole)before fitting the ally cap. it made it quite short and neat looking.