General Improvements..

[Pimpvehicle]

Trying to improve the engine power and MPG on the Cavalier, The SPi unit doesnt look that modifyable tbf..

Going to run a CDA style intake setup
De cat and straight through backbox
Oil breather - No more oil fumes into the engine
97/98 Ron plug - Where do you find/buy them?
Advance/Retard ignition? - What exactly does it do?
Bosch super 4 spark plugs
EGR Blank - If its only connected to the inlet how does it recirculate exhaust gases?
Performance Camshafts? - Is there any direct swap upgrades or aftermarket only?
Redex - Clean the injectors
Clean the inlet manifold
Uprated ignition leads? - If they exist
Lightened flywheel? - If possible

Im not looking for major increases just a slight improvement and get it running above 100bhp As 90bhp for a 1.8 is poor. Considering the Vectra runs 130.

Just the odd random question, how big is the intake on the "top hat"? I would be able to answer it myself but the police currently have my car for running it with no exhaust whilst i was modifying the standard one..

How many pipes come off the top hat? I know there is;

Oil breather
Airbox - Opens exhaust heat pipe
MAF sensor - Which i only found out today from reading Robs post.
EGR valve

Thanks in advance

[Robsey]

Trying to improve the engine power and MPG on the Cavalier, The SPi unit doesnt look that modifyable tbf..

Going to run a CDA style intake setup
De cat and straight through backbox
Oil breather - No more oil fumes into the engine
97/98 Ron plug - Where do you find/buy them?
Advance/Retard ignition? - What exactly does it do?
Bosch super 4 spark plugs
EGR Blank - If its only connected to the inlet how does it recirculate exhaust gases?
Performance Camshafts? - Is there any direct swap upgrades or aftermarket only?
Redex - Clean the injectors
Clean the inlet manifold
Uprated ignition leads? - If they exist
Lightened flywheel? - If possible
Im not looking for major increases just a slight improvement and get it running above 100bhp As 90bhp for a 1.8 is poor. Considering the Vectra runs 130.

Just the odd random question, how big is the intake on the "top hat"? I would be able to answer it myself but the police currently have my car for running it with no exhaust whilst i was modifying the standard one..

How many pipes come off the top hat? I know there is;

Oil breather
Airbox - Opens exhaust heat pipe
MAF sensor - Which i only found out today from reading Robs post.
EGR valve
Thanks in advance

You can turn your Octane Plug over - it is 95 on one side and 98 on the other.
Unclip from holder, unplug, flip over, plug in, and clip back in.
The result of doing this though is that you will induce pinking when driving at anything more than minimal load.

Up-rated leads, well I have always fitted OEM leads, but even the best should be changed annually.

Fitting a lightened fly wheel makes the engine more responsive to the throttle (when there is no load), but if it is too light, then you will feel the pulsing of the engine, each time a spark plug fires.

I think that you have basically covered all the hoses to the throttle body cover.

1) Big air intake
2) middle size - cam-housing breather pipe
3) vacuum pipe for hot / cold air flap
4) vacuum pipe from throttle body.

The MAP sensor is ported lower down the rear of the throttle body.
The EGR valve is ported low down on the right side of the throttle body.

It has always been said that the C18NZ CFi is damned near impossible to tune up. May be better to fit a multi-point injection cylinder head, complete with manifolds etc.

Don't think porting of the head will make that much difference either,

Basic response to tuning up the 1.8CFi, is to : -
1) ensure that the leads and plugs etc are all good / new items
2) Cap off the EGR oriface (remove the valve and fit blank)
3) clean all breathers, including the gauze in the cam-housing cover
4) Ensure that your timing is correct. and so on.

basicly, other than the EGR bit, it is just a matter of a damn good service.

Hope that hasn't burst your bubble... "POP" !!!!

[Pimpvehicle]

Where is the ron plug? And what do you mean by "pinking?"

Where would i find a MPi unit and head?
Does the MPi inlet not fit the SPi head?
Also how would i run it? Would i need to change the ecu

And every engine is tuneable just at what cost really.... Dont Nova's use the C16NZ in the Nova?

I found a nova on my mates farm the other day and it looked like the C18NZ but had MPi injection. But obviously wasnt a 1.8...

[Cavalier342]

The fuel octane plug is in the very far top right corner of the engine bay, behind the strut top mount. There are 2 plugs there, the one with the number on it is the RON plug.
Referring to Robsey's post, its only 95 and 93 as opposed to 95 and 98. At least it is on mine. Unless its been changed but from standard, it should be set to 95.
Pinking is basically where small "pockets" of fuel/air combustion happen where they shouldn't. Basically like a gun going off half cocked. Usually happens if the fuel that's used is too low in octane for the engine. It will do damage to the cylinder walls if left unchecked. It shouldn't happen on a Cav in this country, as the fuel here is good. If you start running a Mazda RX-8 or something similar on regular gas, you're asking for trouble.
I don't think the MPi inlet will fit the SPi, and changing the ECU is only necessary if the current one is faulty or a different engine is installed.
Hope this helps.
Andrei.

[Robsey]

Most RON plugs or Octane Coding plugs are rate to match the fuel grade

In the uk these are Unleaded = 95 Ron and
Leaded or Super Unleaded = 98 Ron.

I'm sure 93 Ron hails back to the old days of 2 or 3 star fuel, but I haven't seen them at petrol pumps since the late 70's / very early 80's..!!

Here is a table from Vauxhalls EPC for the octane plugs that are made for the Cavalier Mk3.

download/file.php?id=791

Pinking, is where the fuel is detonated at the wrong time, and causes a percussion wave through the cyclinders. As said above, long term pinking may cause damage to the engine.

Regarding ECU's, then these are particular to a specific engine set-up.
The C1*NZ engines all use Rochester Multec Single point injection (SPi), often called central fuel injection (CFi).
Other multi-point injections, use different ECU set ups, such as Simtec, Multec S, Jetronic and so on.
So yes the ECU is specific to Injector type.
Your current multec ECU will not work a multi-point injection system

I have heard of multi-point cylinder heads being grafted onto the engine block of a single point engine. (There is little difference between all 1800 engine blocks in the cavalier range.)

If you use a cylinder-head from a 18SV, then this should be fine.
The SV does not need a Cat either!! as long it does not start with a letter at the front such as C, Z or X before the 18SV.

I'm sure that someone else who has done this will let you know what is required. Or alternatively, if I am talking rubbish.

[Cavalier342]

You definitely know what you're talking about, so you're not talking rubbish. We're all here to help how we can, and it definitely helps
As for ECU's, any ECU can be remapped to gain certain advantages, but i am not an expert in that, however i know someone who is. Should you be looking into remapping ECU's, i can give you a number of who to contact. Anyone else, too for that matter.
Andrei

[Robsey]

I'm not an ECU expert either, but I believe that there are wiring differences between the different makes...
simtec, multec, jetronic and so on.

Single points will only have 1 injector output wire, whereas multi points may have 4 or 6.

Also some ECU's use MAF sensor impulses, that need to do mathematical calculations for the cooling rate of a hot wire sensor, whereas the multec specifically uses a MAP sensor, which works off a voltage level that is affected by the vacuum acting upon the sensor.

Some ECU's run 1 knock sensor and others have 2 (V6's).

Note also the multec O2 sensor is a single wire item, whereas some other systems have a heating circuit (4 wire sensor) to get the sensor upto temperature quicker.

These are just some of the differences that affect the construction and wiring layout of the various ECU's.

Apologies, if I sound critical, this is not my intention. Neither is it to cause any offence.
I just wanted to add some explanation / reasons for my comments.

[toptune]

the spi throttle body can be modded,same with inlet manifold,exhaust manifold,skim cylinder head,port cylinder head,run mpi pistons, custom build your own exhaust and set timing to match set up,up-rated h t leads, adjustable fpr
dont think the spi ecu can be re-mapped,
i run a ported and polished cylinder head

[Pimpvehicle]

What power are you running?

[Envoy CDX]

Right couple of things, due to to the crank sense wheel (that reports the pulses tothe ecu) you can't put mk2 jetronic 1.8 mpi kit on mk3 kit - the pulses just don't line up.
You could try a 20ne head on, but you'll need the ECU, and associated wiring.

MPi inlets have a different port and stud layout to the SPi's and the vectra 1.8's are all twin cams.