1.2i cam, c16nz cam

[mattbourne]

hi guys i have a 1.2i and have been reading the tuning guide dedicated to the spi's and it says about putting a 1.6 gsi cam in it, i found this one on ebay for the c16nz engine which isn't the gsi is it??? this is for spi but the gsi is multi point isn't it??? would i benifit any thing by fitting one of these?? any help would be grate cheers guys in advance! matt :thumb:

http://cgi.ebay.co.uk/VCK776-NEW-CAM-CAMSHAFT-KIT-VAUXHALL-ASTRA-BELMONT-NOVA_W0QQitemZ230349357700QQcmdZViewItemQQptZUK_Ca rsParts_Vehicles_CarParts_SM?hash=item35a1e44284

[jimbob-mcgrew]

ive got a feeling the carb (16SV), single point (16NZ) and the multi point (16SE) use the same cam profile, but im not dead sure.
i think the single point cam uses a slot drive, the carb variant uses pin drive, and im not 100% on the mpi version, i think that might be pin drive too. it might be a straight swap if your lucky. wait for some other replies tho as i cant guarantee anything. :thumb:

edit : just had a look at the listing, looks like its got both slot and pin drive, so in theory it should go straight in and flood your engine with petrol lol
you might have to change the throttle body on it too to match the fueling ?, possibly a 1.6 ecu too ? i dont know a whole lot about spi's.

[mattbourne]

lol cheers dude!!! much appreciated!!!

[craig green]

iirc you play with the fuel pressure to tune the fuelling.

I would have expected the GSi cam to be a bit hotter in terms of valve opening than the lesser spec 1.6 cam. An Autodata book will answer that question however.

[jimbob-mcgrew]

yeh i woulda thought that too myself craig, but a while back someone on here linked me to some technical data on this particular cam, and the lift and duration figures were the same for all 3 variants, it mighta been wrong, but it looked fairly professionally draughted to me.
there was however still a big debate between the slot and pin drives of them, as it seemed they made the majority of these cams pin drive, but slot ones were also made, or in this case uniquely its got both.
again i cant guarantee any of the above info, but hopefully you can get some understanding of whats required/needs doing to switch the bits and make it work :thumb:

how do you change the fuel pressure on the spi's craig ?

[mattbourne]

good question i thought that fuel pressure can only be changed/uprated if you have mpi!!! as they only make fuel pressure regulators for the higher spec novas eg: sri,gsi

this is very complex!!! studying mechanics at college at the mo and currently on engines maybe my tutor could help???? cheers guys

[jimbob-mcgrew]

an upgrade with better results would be to scrap the spi head and inlet for 1.2 carb items, 45 to 54 bhp (9 bhp gain) maybe you could slap a 1.3 cam in the head while your there, might push it to 57/58 bhp, better exhaust manifold on that and youll be lookin at about 60 horse, a 1.3sr inlet manifold and carb would prob unlock another 5 ontop of that. all that costs money tho, get more bang for your buck dumping in a bigger engine. forgot to mention you need to swap the petrol tank and lines to run it carb.

[shrtwrec20]

Just My 2 Cents. Back when I had a spi I remember fitting a piper High lift cam and honestly hardly noticed the difference. But when I fitted a decat pipe the increase in power was noticeable

[jimbob-mcgrew]

^ yeh eliminating bottle necks is sometimes just as good as upgrading

[vauxboi]

hang on so your saying you will need to uprate the fuel pressure if you put in a 1.6 cam. Ive got a 1.2i and a 1.6 cam no one has told me to uprate the fuel pressure