potentially crazy gems to bosch idea

[Eevo]

so my 4.6 p38 (the one that i havnt introduced to the forum yet) is at 250k km so a rebuild is probably coming up in the next 12 months.

my 4.0 d2 is getting a ls1 conversion. so i'll have lots of spare v8 bits.

the 4.6 is gems
the 4.0 is bosch

is there anything in the bosch system that can be reused as an upgrade?
ecu, intake, etc etc for example? i've read some ecu's have both 4.0 and 4.6 maps in them, but i got horribly confused which ones have it.

[Hoges]

Not so crazy actually...I'd have thought like you said, that you could swap over the top end...i.e. upper and lower intake manifolds, fuel rails and injectors, throttle valve/throttle position sensor etc. and associated hoses. Also the ignition coils. Probably also need to look at the cruise control cable etc. Don't know about the EMS... and whether you will need to re-sync the EMS with the BECM as part of the immobiliser system...
The Bosch set up has a different CKPS (crank posn. sensor) and also a different camshaft sensor.

The other alternative is to refurb the GEMS engine...the Bosch Motronic 5.2.1 EMS is virtually impenetrable in terms of engine remapping. I suspect you can tune the GEMS to get far better power and torque for a lot less money.

I am mightily interested in yr LS1 conversion. It's a great engine and even in standard form would be ideal. There were a couple of blokes some years ago in the UK who developed a bellhousing etc for the LS1 conversion but retained the GEMS sensors etc...so effectively, a Rover "system" running a GM long engine. They went broke but had the prototype running on LPG. They also used a different grind (less overlap at lower revs?) on the LS1 camshaft to improve low speed torque. IIRC the LS1 develops max torque at about 4000 rpm, but there's a lot of it between 1900 and 3000 rpm...

cheers

[PhilipA]

IMHO, you would perhaps be better to run the Thor inlet manifold on the GEMS engine management.

AFAIR the GEMS has a conventional injection with front mounted regulator while the Bosch has a one way system with the regulator in the tank, and runs a higher pressure to the injectors, so you may have to replace the tank and fuel lines if you wanted to fit a Bosch system to a GEMS car.

The main hurdle would be to arrange for a IAC system as the Bosch has a rotary valve and the GEMS a cone type IAC.
At least you would not have to worry about a kickdown cable , as I had to when I fitted a Thor to a 14CUX.
Regards Philip A

[Eevo]

IMHO, you would perhaps be better to run the Thor inlet manifold on the GEMS engine management.

this sounds like an idea.
would there be much improvement? just better flow/response?

edit: i've also read this is not a simple/straight swap.

[PhilipA]

The Thor manifold has runners about a metre long between the port and the throttle plate . This will give a much better charge at lower revs, but cost power at high revs.
My 14CUX gave a 50% increase in power tapering up to 3000RPM, with a loss of 10% power at 5000RPM. This was also with head work and Unichip.

So its up to you really what you want.
the tricks needed are
1 an old RRC fuel rail which has the fuel temp sensor at the front.
2 rig up an IAC valve
3 make sure the TPS works. I used my 14CUX TPS , but I think the Thor one will be plug and play.
4 maybe amend the inlet for the engine ventilation, but if you have the rocker covers off the Thor that should be OK.
5 accelerator cable may need to be longer but that was OK on my 14 CUX, so probably OK with GEMS.
Its pretty simple to me.
My main problem was the kickdown cable, and I don't think you have that in a GEMS.
Regards Philip A

[Eevo]

i'm a tad confused.

i thought GEMS and 14CUX were different system.

14CUX is an efi system used between 90 and 95
GEMS is an efi & spark (i think) system used between 95 and 99


edit: ignore this post.
i understand now

[ozscott]

250,000 is nothing for a well maintained rover v8...why do you think that these K's mean rebuild?

Cheers

[Pedro_The_Swift]

maybe cos it wasnt maintained???

[Eevo]

250,000 is nothing for a well maintained rover v8...why do you think that these K's mean rebuild?

Cheers

hmm,, good point.

[Eevo]

make it to 270,000km and the HG let go.
serviced every 10,000km

how what to do? lol