Posted by jonno_racing on Saturday, December 11, 2010
Ok i have been asked so many questions about the gti to sierra that i thought i would do a complete start to finish.
The g13b is a great little more with nearly double the standard power and more torque, that with 6.5 transfer gears and 31's is a killer combo in my sierra.
Ok for starters this conversion was done in my 98 coil sierra so it has SLIGHTLY different electrics but it is basically the same
What you will need..
G13B Engine with all the manifolds etc
Rb30 VL engine mounts
Ok so i HIGHLY recommend rebuilding your G13B before you start, it might save you a fair bit down the track (as it would of me)
you will need to swap over your oil pick up, sump, engine mounts (using the VL mounts is recommended) Clutch cable mount, fly wheel, clutch etc off your sierra motor to your gti motor, this is all a straight swap over
i also recommend changing to a heavy duty kit as my g13b was spinning the clutch on the dunes
So this is how i did it.
lay your harness out on the floor and work out and mark what needs to be kept and what is now no longer required, the benefit of the Mk1 is the ecu controls Fuel only so there is no need for the ign side of the wring any more.
Basically all you need to keep is injectors, temp senders, afm and tps
once you have the loom on the floor it should look ruffly like this
and this is the amount of wiring no longer required!
I mounted the computer on the firewall behind the glove box as it was a nice easy to get to location, i also replaced fuel pump and computer relays with new after market jobs that are mounted above it.
the actual wiring of the efi into the car is quite simple, you need straight power from bat, Earth, ign, start, earth from your coil also your computer will have a pin out that must go to the earth of the fuel pump relay or it wont run!
there are very few sensor wires that can actually be shortened with the conversion, due to them being set Resistance for tuning. so i didn't bother with this and i have a Coil as such of wiring under my dash.
Ok i made my own 90' dizzy drive using my original sierra dizzy and the mk1 dizzy
basically i cut down the original mk1 dizzy and got a new shaft made for it with the 90' drive gear from a standard single cam head pressed on it.. then drilled and tapped some holes in the base of it and bolted it all together. i also used silicon to seal the 2 housings together and packed it with grease
you can then run standard gti leads to your sierra dizzy. the only issue i have had with this is due to timing, basically the gti and sierra dizzy have different advancing curve so you will need to set the gti motor to about 6' to get it to run fine on 95octane without pining.
you will need to swap the coolant rail out of the back of the water pump with a sierra one, it should be a straight swap over, but replace the o-ring whilst you have it apart to save a leak later on!
For your top hose something custom will be required, i used stainless tube to run under the inlet manifold with a 90' bend into a earlier g13a single cam swift thermostat housing
i have also used a mk3 gti thermostat housing (engine side) as this has a different bolt pattern and allows the thermostat housing to be pointing in the correct direction for the hose
I also HIGHLY recommend replacing the thermostat with a GENUINE Suzuki job, should be around $30 and it is hard to change in the car! i have had many issues with aftermarket ones!
i replaced my radiator with a larger jimny unit and a large thermo off a TE magna that was a PERFECT fit!
i was lucky in doing my conversion that i have a coily as they have a different fuel tank, that allowed me to run a vitara efi pump that is a straight bolt in, i also used a metal fuel filter off something, (just look though the box's at super cheep till you find a metal filter with 2 barb endings and that will do) i also replaced fuel line from the tank to the engine with rubber high pressure line, expensive but worth it
you can use your sierra extractors BUT you will need to cut the engine flange off and get a gti one welded on. as they are different!
i simply used some 2.5inch flexible hose for mine.
Ok well u should allow about 1500-2k depending on a few factors. but as always work out what you think its going to cost you, double it.. and that's about what it will!
And that's about it. i think i have covered all things.
some notes.. GTI motors do not like to be hot.. it should run about 90-100' and i have had 2 motors die due to being hot under load!
ok some more pics that might help you