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Discussion Starter #1
Hi all, Im preparing a MK3 astra for rallying, The only car i could find without a sunroof was a 1.4 Single point injection. It has bags of torque but doesnt rev very well. Would a 1.3 astra/nova inlet manifold fit? (pierburg) I could then throw a Webber on that. How about a late nova SR 1.4 setup? I have thought about putting the MPI off an LS on it but dont really wish to go that route. Also are the mpi/spi cams the same and will one fit the other as i'm not sure if aftermarket cams can be bought for the spi type engine.
Any help much appreciated.

ta.
 

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I'm pretty sure that the cams in the 1.4 MPi engines have a higher lift than the ones in the SPis, but they can be swopped over.
The inlet manifold on the 1.3 engines has rounded ports on it and the ports on your SPi head are square, so if you plan on keeping the SPi head, you'd be better off with the inlet manifold off of a 14NV engine (1.4 carb). The best thing to do though, would be swop the head with the Lotus designed one from an MPi model and use that. They are a much better head. Headwork on these can apparently see gains of up to 20% in torque and acceleration.
I'm not sure if the injection engine cam housings have the section for you to fit a mechanical fuel pump into, so you may need one of these off a 14NV aswell.

Cheers,
Kieran
 

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Come to think of it....

You'd probably be best with a cam off the 14NV aswell, as the injection cams might not have the lobe to run the mechanical fuel pump off.
Just checked the Haynes manual and the camlift for the C14NZ is 5.2mm inlet and 5.6mm exhaust, whereas the lift on the 14NV cam is 6.12mm (on both the inlet and exhaust side).

Cheers,
Kieran
 

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Discussion Starter #4
kieran, Many thanks for the replies.

My mate has the MPI astra and mine seems to have much more torque. I presumed that this was due to the head/cam design, Which is why i wanted to keep it.
On a side note, Do you know if the ECU controls the fuel supply or does the pump work on pressure like it would with a carb?

cheers.
 

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na the MPI has more torque its just the way the SPI delivers it gives that impression
 

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jester said:
My mate has the MPI astra and mine seems to have much more torque. I presumed that this was due to the head/cam design, Which is why i wanted to keep it.
On a side note, Do you know if the ECU controls the fuel supply or does the pump work on pressure like it would with a carb?

cheers.
The C14SE/MPi produces 113Nm torque at 3400RPM, whereas the C14NZ (SPi) produces only 103 at 2800RPM. I don't know why Vauxhall ever called the NZ the "High torq" engine - I guess they had to find some way of shifting them :).
The fuel pressure delivered by the pump is a constant pressure, but is controlled by the pressure regulator - i.e. it takes what fuel it needs and then sends any excess back to the tank through the fuel return line. The ECU controls the amount of fuel going into the engine, through receiving signals from various sensors under the bonnet, such as the throttle position sensor, crank angle sensor, lamba sensor and the idle control valve. The ECU takes the info from the sensors and then, depending on what values it has received, sends a signal to the injector(s) to allow X amount of fuel into the engine.

Hope that helps :)
Kieran
 

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if it hasnt already been said, the inlet manifold from a 1400 nova SR will mate straight up to the 1400 spi head.

1300 sr is no good, has to be 1400.
 

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Discussion Starter #13
Sorry to go on about it but... Will the CAT be affected at all? For MOT purposes of course. Also, When i put a performance exhaust on it what about the CAT then?
Apologies for all the questions but ive never dealt with injection/cats before.

Ta.
 

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Would it be possible for you to fit the CAT purely for the MOT and then remove it again afterwards? The CATs do reduce the power quite a bit.
Do the MOT testers in the UK test the emissions according to the age of the engine, or the age of the car? Just wondering, because if they do test them according to the age of the engine, if you were to use a 14NV block from a MK2 Astra or Nova i.e. pre '92, then you wouldn't have to worry about emission levels as much......or do you have to have a CAT regardless of the age of the engine?

Cheers,
Kieran
 

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Discussion Starter #16
Afaik it's the age of the car and not the engine, Interesting thought though, I'll investigate that one.
 

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You might as well investigate, seeing as there's nothing to lose :)
Out of curiosity, why are you using a 1.4 engine for rallying? Are you restricted from going any bigger, or are you just doing it for the fun factor to see what you can squeeze out of the 1.4? :)

Cheers,
Kieran
 

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Discussion Starter #19
I've always ran in the 1400cc class, Used to use a mk2 astra 1.3. The boys who are running the 1.6/2.0 are piling loads of cash into their escorts/sunbeams etc... I just prefer smaller engines and the vauxhall fits the bill perfectly. All i fit is a Weber carb, Cam, Filter, Exhaust, sc/cr gearbox with a 4:6 diff and get the flywheel lightened and balanced. It's surprisinlgy rapid down the lanes, Top speed dies around 90mph but the acceleration is nice... :) The reason ive gone for a MK3 is because 3 door mk2's without a sunroof are now very hard to find. If anyone has any advice in setting one up etc i'd be happy to listen ;)

Thx.
 

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Ah, I see. Sounds like a nice, simple setup you have there. Did you have any luck rallying the Mk2 1.3? :)
As for setting up the Mk3, I'd imagine it'd be very similar to setting up the Mk2 wouldn't it? The suspension/steering setup seems to be the same apart from a slightly different subframe on later models. A lot of people say the handling was never as good on the Mk3s as it was on the Mk2s, but I wonder if that was due to the ET46 offset that was used instead of the old and preferred ET49.

Cheers,
Kieran
 
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