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MC
19-11-02, 02:33 PM
To save the same questions keep cropping up, here’s a few ideas, feel free to add your comments tips and experience:

Before commencing any engine modifications, it is advisable to ensure that all of the basic components are working well. This will save time and money. The engine itself should be in sound condition with no unusual knocking noises and no smoke. There’s no point spending money on an engine that is going to fail. Also check that the ignition system is in good working order. If in doubt use new plugs, leads and distributor cap, nothing fancy, as long as they work, they’re fine.

This guide is based at getting power on a strict budget. Even this will cost money, so if your only driving this particular car for a short while until you can afford something faster, don’t bother, save your money. If however you see it as a project to get a quick little engine car and have fun, then these tips should be helpful. The only way you can really save money on any modification, is to do it yourself. If you are paying someone else, then change your pay details so that the money goes direct to the garage!

One last thing, if you have limited power, don’t fit big body kits and wheels, I guarantee they will slow you down. I lied, another note, lose weight, drop the huge stereo system, and if you can bear it, strip some interior, it will make more difference than spending ?500!

Ok, on to tuning the 1.2:

You need to start hunting around the scrap yards.

Exhaust
You need to get a system from a GTE/GSI ideally. The SR models will still be an improvement, although I believe diameter will be bigger on the 1.6’s. Get the manifold, down pipes, and full system. The design is better with the twin down pipes, and this will flow the gasses out quicker. You’ll probably have to shell out around ?50 for the lot, but it will be far better than buying a ‘performance’ back box.

Head
Stick with the one you have. It flows well, and will start costing to much money to play around with. If you really want to help, match the manifolds to the head by cutting the gaskets to the size of the manifolds and then taking metal out of the head to match the gasket. Personally for a beginner I’d say not to bother. Its quite involved and you could do more damage than good. Cost ?0

Camshaft
Once gain the GTE/GSI is the best source. The camshafts are interchangeable, so the SR one will fit too. This will give increased duration and lift, but beware, try to use the followers that are with the new cam, and in the correct place. Also look at the amount of wear. There is no point picking a cam coz it is suppose to have 2mm higher lift over a longer duration if there is 4mm of wear on the followers. Try buying new ones if you can stretch to it, and come to mention it, buying new ones for the standard cam will probably bring back a few missing ponies. Costs: Cam: ?25

Inlet
The simplest and cheapest way forward is to find yourself a 1.3sr. It must be a 1.3 and not the 1.4 as they are very different. You’ll need to take the carb and its manifold. The manifold will fit on the 1.2 head, and hey presto, you have a twin choke. This isn’t the ultimate solution, but it is a vast improvement. Cost is gonna be ?50 plus from a scrappy.

Now this should get you SR (ish) performance. Not a rocket ship, but it’ll be more fun to drive. There is a lot more to do, but realisticly, it’s not worth the extra expense. Don’t overlook the brakes and suspension!

Insurance is a consideration. You’ll need to declare the carb and exhaust, both of which will have minimal effect on your premiums, if any at all. The camshaft however will never be noticed. I’d bet money on that.

This all adds up to around ?125 (not bad for a 15+ bhp increase), you might be able to get bits cheaper or even for free, some scrappies might charge more, so expect to shell out between ?50 and ?150. Don’t forget about consumables such as head bolts and gaskets, coolant and most importantly you’ll need a haynes manual!

Anton
19-11-02, 03:23 PM
cheers mc :lol:

Nova-Flair
19-11-02, 06:40 PM
any tips for injection inlet???? will the GTE/GSI system be a straight fit???

D7AKE
19-11-02, 08:06 PM
Could I not just swap my 1.2 cam with a GTE one or do I have to change the followers springs ETC

Si

mowgli
19-11-02, 08:44 PM
If you are fitting a s/hand cam, always use the followers that came with it, in their correct order, but fitting a new cam is better.

If you do the 4-2-1 exhaust thing, everything back from the downpipe is the same. a new downpipe is not much, and you can used the manifold from any 1300 vauxhall model. Apparently there is a good gain from getting a grinder and smoothing out the bit where the two downpipes join, the astra/nova challenge racers used to do it.

If you have the ac delco dizzy, and the bob weights are not rattley, always check the vacuum advance mechanism, simply suck on the pipe and see if it moves. cheap fix, better power.

If you can't afford K&N just swap your std air filter regularly. also rig up a cold air feed for summer use.

Keep the faith I got a good 80000miles from a 1200 before she blew a piston ( the girlfriend was driving)

ednovasr
20-11-02, 11:25 AM
:x I got a 1300 SR mainfold and down pipes, then went oput and bought a full magnex stainless steel system cost ?280 including fitting al the bits!a quick bore and polish with a dremal multi of mainfold and down pipes for smooth gas flow.

Then hand a 1300 piper hight lift/road/raly cam at ?265 for the full kit including fitting, polish of valves and out let's (zorst ones)

Them I went for the bosch super 4 plugs ?20 magncore leads ?40 and the result I was very skint!

Add to this I found a K&N in a scrapy in the back of a old granada 2.5 v6 I took that put it on a astra it fitted perfectly so waa 1300 sr one I thought to my self.bought it as well bloke wanted ?10 and It wasn't in to bad a state!So got a mate to swipe the fitting roads form work and some shinny bolts (he owed me a favour)

For what I saved on insurance I could of bought a GTE and insured that!

280+265+20+40+10=?615 then there was the surspension another ?285 -60mm full kit and new Spax progressive bump stops ?12.99, as standard ones wear out the rid gets like U have no shocks!
So thats so far not including all othere interchangable bit 615+12.99+285= a total of ?912.99

For a 79bhp not woth it! I was robbed that nearly ?1000
Could of got a GTE for ?500 extra smae price is some cases and then paid ?500-700 more on insurance Max!

Car now has three year later 89,000+(oh and one new valve)on the clock a 1300 twin choke carb & now I'm waiting for it to die at the hands of my misses. So can put a nice fuel effecient 1.4 16v in it's place. Whilst I kick her ass in my little Jap import Turbo!

MC
20-11-02, 01:37 PM
For the single point Inj, you're gonna have to change to a carb. Now the grey area here is the head. I'm not sure if it's the same design as the carb'd 1.2. If not then you'll need to change the head too, and start spending too much money. Does anyone know the inlet port shape of the 1.2spi?

Yes the manifold and system interchanges between all models. Change it all together as I believe the seperate systems don't always mate up.

As said before, make sure you use the follower that is already with each lobe. Do not mix them up. You can get away with buying new followers only. They are designed to wear quicker than the cam, so the lobes should be pretty equal. Followers are not too expensive.

FAO: ednovasr.

I believe the first paragraphs of this post covered whether or not it is worth modding. This needs not be talked about yet again. At least people have the information here to decide for themselves. I do see however that you did throw too much money at a 1.2. That is why I suggest buying parts from scrappies and have written this budget guide. I would never spend nigh on 1k on a 1.2. The work mentioned can be done for under ?150 if you try hard enough, and for that money its not a bad option.

Thank you all for your comments. Lets keep this to a how-too rather than a whether-too.

Any other tips?

jon_boy
21-11-02, 10:50 AM
Ive now done all mentioned in the first post and its amazing the difference it makes! I then stripped out everything behind the back seats. this way i save money on feul consumption and have a great excuse to only give my girlfriend a lift and not her scatty mates. but more to the point it also makes it take off that bit quicker! thatnks for all the pointers lads! jon

Ste_Nova
22-11-02, 10:47 AM
what about modding the 1.0

mowgli
22-11-02, 08:03 PM
1.0 is not worth modding, they did do a 1200 version of the OHV that was fitted in mk1 & 2 astras that apparently fits straight in. not sure about unleaded compatability though... Fit a std OHC engine/box.

Cheers

Tazzy
02-02-03, 12:38 AM
lol, but i guess a 1.0 just isnt worth it, what mods are avaliable for it?

Tazzy
06-02-03, 11:50 PM
a topic has arisen on another forum i use, about the lambda sensors, someone has said that some modern ones run a twin lambda setup closed loops system, if the 2nd lambda value (after the cat) reads too close to the 1st lambda, it will possibly run into some problems, or summit like that, is there the twin on the cat systems on novas?

but i was told that no novas had a cat in the first place?

wisewood
07-02-03, 02:03 PM
Once the laws changed requiring cars to be fitted with a cat, obviously vauxhall fitted them to their cars. Newer nova's have it, older ones dont.

Stuart
07-02-03, 02:23 PM
ive been doing an entire module regarding twinc lambda sensor systems (this was on a 2l Honda Vtec) and the first controls the "general" emissions and the second does minor fine tuning to the system so that the exhaust gasses are as clean as possible. they are using titaium oxide sensors and compare values, its also got the benefit of being able to tell you when your cat is knackerd.

Nova-Boy
17-02-03, 12:58 PM
If you want speed not looks then get rid of the big alloys. I had 13" standards on mine and it was nippy. Now with 15" 195's it is a lot slower on acceleration.

Nova Modder
19-02-03, 04:32 PM
dont alloys have better cornering traction??

what about 14" rims with low profile tires to keep the same rolling radius as the std 13"'s with high wall tires?

wisewood
19-02-03, 04:46 PM
Cornering is improved by using wider wheels.

The rolling distance of the wheel should be kept as close to that as was as standard as possible for performance.

Do not go lower as you will lose out - do not go too much higher or you will lose performance.

Nova Modder
20-02-03, 11:57 AM
hey guys, just went down to my local alloy wheel shop, and found out some tire information for yall :)

basicly if u got

14" 's then u want 185 / 55 / 14 tires
or get 185 / 60 / 14 tires ( wide may need rear arch rolled a bit )

if u got 15" 's then you want

195 / 45 / 15 tires

thise tyres make sure your car has the same rolling radius as your original 13" steel wheels you once had :)

Nova-Boy
25-02-03, 09:12 AM
What is the deal with tuning a 1.3sr??

Dont bother and get a 1.4sr and tune that??

wisewood
25-02-03, 10:45 AM
Follow same principles as detailed in teh 1.2 and 1.4 guides... adapt where necessary.

Nova-Boy
09-03-03, 01:50 AM
I am about to do all of the mentioned mods. I have a apare 1.2 head so does anyone have any advice of how to play with it (dont matter if i fcuk it). Also anything new cropped up to tune a 1.2??

I heard that the 1.4 cam had higher lift than the 1.6 should i use that one??

I want to get it right so i can piss on all the other 1.2's in my town!!

mikeoxford
09-03-03, 11:12 AM
I heard that the 1.4 cam had higher lift than the 1.6 should i use that one??

yes