GT to G40

Started by Langsam, July 28, 2011, 11:03:02 PM

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Langsam

Im just wondering what are the differences between the two engine exactly?

Obviously one has a supercharger and one doesnt.

Thanks

PeteG40

bottom end is differnet with different compression ratio
head is different with different valves
Exhaust manifold/down pipe is bigger on g40
inlet manifold is different (but gt one can be used)
throttle body
ecu
gearbox
alternator

Langsam

So i surpose you couldnt just put a decompression plate on a GT engine then wind the boost up then?

PeteG40

you could but you'd need the right engine management for boost etc  check out chris heys - cheys - 1.3 mk3 polo turbo build thread for an idea... his was a 1.3 single point, which is similar to a gt but without the high compression ratio.

Langsam

#4
Right ive decided to do what chey has done but im a bit stuck with regards to CR, Im gonna be using my GT engine because I know the history quite well and I have a 270 piper cam with a ported and polished head fitted already.

The engine has always had a carb fitted to it, so i am now ready to take it to the next step. Ive seen on ebay you can get de-compression plates, I was thinking of fitting one to lower the CR to be on the safe side. What I am quite confused about is the electronic side of things with my polo being a early mk2 carb.

I know I will need a g40 ecu to make it run but I would I be best off gettin a G40 wiring loom aswell?

How could I mount the knock sensor and what would I plug it into?

Langsam

Would a GT head work on G bottom end??

hayesey

as long as you put the g40 cam in, the head itself is the same

Jezza-7

If you can get a wiring loom then thats your best bet mate. Its a lot easier but there hard to come buy now days. And i think there quite a lot too.

Langsam

#8
cheers hayesey

Ogh right, that aint good, ok cheers Jezza

Im just gonna stick with a de-comp plate with my 3F.