1.2 engine mods help

[timmcf]

just got a 1.2, she is quickish but not quick enough
can you get a power boost valve for a 1.2? where?
getting a stainless steel exhaust which should help a bit!
what else could i do to improve performance? that isn't very expensive
(under ?500 in total)

[Stuart]

which 1.2 is it? the carb or the spi version?

we can go from there... lol

[timmcf]

oh right
well im not sure at the mo in college you see!!
which is better?

[Stuart]

the carb version is generally better.
what year is it? that might help a little if you cant see the bay

[johnny27]

just got a 1.2, she is quickish but not quick enough
can you get a power boost valve for a 1.2? where?
getting a stainless steel exhaust which should help a bit!
what else could i do to improve performance? that isn't very expensive
(under ?500 in total)

you can't fit a power boost valve to either the spi version or carb, along with most other of these plug in mods like chips. If its not the carb model the first thing to do and the basis for the rest is to convert it to carb spec, along with the carb head.

[Gunzi]

Put a 1.3 or 1.4 SR engine in there it would give you a better starting point. You could probably buy, fit and insure it for ?500

[timmcf]

how much would is cost to convert it to carb if it was an spi?
its 1993
so change it to carbs, put big carbs on then what?
cant afford to insure a 1.3/1.4

[Stuart]

thats an spi model.

basically you need a carb head, inlet, carb, fuel pressure regulator and IGN system (dizzy, coil). its probably cheaper to buy a whole 1.2 engine and fit that than to fanny about rebuilding the 1.2 spi to the carb spec.

[timmcf]

i know what carbs are but what the hell is spi?

[Stuart]

single point injection. Its a glorified carb that has a single injector that is controlled by the ECU (as is the Ignition). It was an easy step to create a closed loop control system to get the emissions down etc.

[novamadman]

i know what carbs are but what the hell is spi?

single point injection

1200 carb engines are better for modding performance wise and someone correct me if im worng but i think they had better bhp standard

make sure u slap on 4 branch with the exhaust

depends on your budget and how much more you actually want

start with better carb - weber 32/34 maybe, 4 branch and exhaust, then go internal if u have the time and money, cam and head work if u can do it yourself ur half way there

shane

[Welsh Dan]

Iirc carb 1.2's are 55bhp standard, 1.2 spi's are 45 ish. I'd go with stuarts suggestion of just fitting a 1.2 carb, then use that as a starting point.

[Adam]

Sod swapping the SPI to carb for a 10bhp gain.
You will need almost a complete 1.2carb engine to do that, early 1.2carb bottom end also has different bore etc to the SPI bottom end.

GTE cam and decat on the spi engine=10bhp.
4-2-1 SRI manifold and downpipe and system=About 5ish bhp
1.6SPI inlet manifold, 1.8spi throttle body=Few more bhp.
Should leave you around the 60-65bhp mark.

And it will start in cold mornings ;) lol

[timmcf]

thank fcuk she was a 92 not 94!!
so she is an spi or carb now?

[Stuart]

still a large chance its a spi

[Ste L]

thank fcuk she was a 92 not 94!!
so she is an spi or carb now?

look at your engine, if you have got 2 bolts holding air filter on it's SPi
if you have 3 bolts holding it on, its a carb engine

[Adam]

Some J-plates are carb, but most J and almost all K will be SPI.

[johnny27]

Some of these mods are already posted here, but i give you my experience anyhow

i think there is ten bhp in the difference of spi (45) model and carb (55) If your converting to carb, get the 1.2 carb head upgraded, skimmed, ports gasflowed and polishing of the ports. Its not worth going much futher with a 1.2 head, the likes of 3 angle valve seats and enlarged valves would not be worth the money for a 1.2 Also get the usual stuff done, seats grinded, replace valve stem seals and so on. You'll need a new head gasket, timing belt, best also to change the waterpump for the sake of ?20, would recommend you get a new dizzy seal when replacing for the carb dizzy.
I would recomend a 4 branch manifold or a sr std 4-2-1, get a decent exhaust system from the down pipe back as you don't need and can't use your your exsiting exhaust because the spi had a cat. For fuelling the best upgrade would be a weber 32/34 twin choke, don't use the 2e3 sr carb because you will have nothing but problems, i presume your not intending to use twin 40s so the 32/34 is the next best carb and can be picked up 2nd hand quite cheap on ebay. You'll need a standard 1300sr manifold for the weber carb too. You could also use a nova gte/gsi/sr 1400 camshaft but i'd reckon that a cheap 2nd hand 285 kent ast1 would be better or i think you can also use the NVO series i think they have similar profiles, a 295 cam may be a bit extreme for road use on a 1.2. Get a new camshaft seal too
The mods i have listed but using a 295 ast2 i done to my old 1.2 spi, the car was totally different after i had fitted these mods. My nova would easily beat sr nova's and slightly better the 1.4sri. I also used a 418 cwp and it really made it feel alot faster with my 50/14/185 tyre's. If your using the weber u need a fuel pressure regulator, and use the carb mechincal fuel pump on the cam carrier, but don't forget to plug out the plug of the spi pump under the back seats
To be honest, i really think the mods where worthwhile and it was'nt that expensive, since most parts where sorced from ebay 2nd qute cheap. And i had little labour costs because i fitted them myself, apart from the 4.18fd i paid a mechanic ?60 to fit it, i would'nt tackle it myself for i'm not a natural or very good mechanic.

[Martin]

Sod swapping the SPI to carb for a 10bhp gain.
You will need almost a complete 1.2carb engine to do that, early 1.2carb bottom end also has different bore etc to the SPI bottom end.

GTE cam and decat on the spi engine=10bhp.
4-2-1 SRI manifold and downpipe and system=About 5ish bhp
1.6SPI inlet manifold, 1.8spi throttle body=Few more bhp.
Should leave you around the 60-65bhp mark.

And it will start in cold mornings ;) lol

So what you're sayin is, To stick with the 1.2i, i was just wondering as i have a full 1.2carb engine as well as spi engine and was planing on fitting the carb bits 2 my spi, i also have a four branch manifold and decat pipe, whats this about 1.6SPI inlet manifold, 1.8spi throttle body? what cars do they come of?

i would like to do this to my engine as i was over taking by a 1.0 AX and couldnt keep up:mad: :mad:

Any help on makin mine abit more faster would be much helpfull



Martin:thumb:

[Welsh Dan]

i would like to do this to my engine as i was over taking by a 1.0 AX and couldnt keep up

pwned lol

[Martin]

lol my cars on nova gsi rims so it couldnt of been that slowing it down, also it felt like ti was getin restricted???

[Welsh Dan]

Is it running on supermarket fuel? if so, run it on shell or esso etc. and see if/how it improves.

Give it a good service aswell.

[the ferret]

Best bet for the carbed engine is a full exhaust system off a GSI or GTE including manifold. more power and a better exhaust note without being to loud

[Adam]

So what you're sayin is, To stick with the 1.2i,
whats this about 1.6SPI inlet manifold, 1.8spi throttle body? what cars do they come of?
1.6SPI mk3 astra inlet manifold(might also have to block the EGR hole too)
1.8SPi cavalier throttle body, which is 45mm, compared to the 1.2's 34mm iirc.

Fit a 1.4spi injector in the 1.8 throttle body.

Fitting a GTE cam makes a big difference.

:thumb:

On my engine, i've done just about as much as you can without spending loads, or without swapping heads etc.
It hasn't really cost me that much at all tho.

Taking it further than that, you could fit a 14se head and a set of t40s, or the 1.4MPI setup on the 1.2 block.
Not sure how it would effect compression etc tho.

[Adam]

Is it running on supermarket fuel? if so, run it on shell or esso etc. and see if/how it improves.

Give it a good service aswell. I'd save the money, higher Ron etc fuel wont make any difference at all on a SPI/carb engine.
As your not altering the ign timing to make use of the higher RON.
SPI have a ron plug, with 91 on one side and 95 on the other.

So having the plug on 95, when paying for and using 98ron "super unleaded" is a complete waste of money.

I use the cheapest unleaded i can find,Lol.

[Welsh Dan]

I didn't say super unleaded. I was meaning better quality fuel. I notice a big difference in the way the engine starts and runs between our local sainsburys/tesco, and shell/esso.

Standard unleaded from each.

[Adam]

Ahhh, i get ya.
I've always just used Bp, queues are too big at Tesco. Lol.

[timmcf]

thanks for all the suggestions guys
i will post up pics later tell un's all how shes getting on!!

[Martin]

Is it running on supermarket fuel? if so, run it on shell or esso etc. and see if/how it improves.

Give it a good service aswell.


Been serviced 10miles ago

fuel is murco stuff but its only round the corner from me, and it was easier to get fuel for it while it was of the road...


any ideas on whats up with it going so slow ? Also it gets rather hot too, like the other day from my house to get MOT'd it (1.5miles) it was on alf temp about half a mile there....?

[Adam]

any ideas on whats up with it going so slow ?
Its probably just normal,Lol.

The overheating could be thermostat jammed closed.
Assuming the drive to the MOT place was none stop and you didn't get stuck in traffic or anything.