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Discussion Starter #1
Hi everyone new to here! I don’t own an Alfa but I do own an Astra with the 120bhp 8v engine. In the Vauxhall world there is next to nothing in regards to tuning information on these engines. I can see why as who wants to tune the 8v when you can get far more from the 16v.
Anyway I’m hoping for some advice at what can be achieved from the 8v engine:
Is there better injectors for them because I’ve searched high and low and it seems not?!
Is there any little tricks to help increase power?

Any help would be massively appreciated as this project started over a year ago. I’ve had some very annoying issues to overcome but I think we are heading in the right direction.

Abit of history on the engine so far:
Gt1756 hybrid turbo with 6+6 induction blades, exhaust blades have been clipped.
Fmic with 57mm boost pipes
Egr deleted completely
Standard airbox with a k&n panel and the trumpets removed. 3 inch air intake pipe from grille to airbox.
2 1/2 inch straight through exhaust.
Oil catch can.
think that’s it for engine mods.
As I said above it’s had some issues so this is the list of sensors what have been replaced:
Boost solenoid
Fuel regulator
Fuel solenoid
Maf
Map (for a 4 bar, over kill but)
Lift pump in tank
Rail pressure sensor
Temp sensor.

thanks for taking the time to read this rambling.
 

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Discussion Starter #2
Oh I’m looking at achieving 200-220bhp. Turbo is meant to be good for that and can run a maximum of 30psi.
It’s not mapped yet as the last time we tried it had a misfire and holding back at around 2000rpm then would clear up at 3000rpm. The dyno figures were very embarrassingly low! 🙈
 

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Its not mapped? That do you think how you gain more power? Without more fuel and more boost, you dont have more power. And without VNT adjusment you have a bad driveability.

And you have installed a 4 bar map sensor without maping?
 

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Discussion Starter #4
Its not mapped? That do you think how you gain more power? Without more fuel and more boost, you dont have more power. And without VNT adjusment you have a bad driveability.

And you have installed a 4 bar map sensor without maping?
no it’s not fully mapped yet as it was been a pig with misfiring and limp mode. Only got so far before having to give up with it. It now drives fine apart from if you do put your foot down on full boost it goes into limp mode for overboost. It’s only looking for 21-22psi and it’s hitting 30 psi! As far as I know the map sensor doesn’t need to be mapped in, I know the maf and the rest of it does? It will be off for mapping soon! Just wanting to see what else can be done with these engines. The hybrid turbo has been on for nearly a year now, this is how much fun we have had trying to find the fault on it previously!
 

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The map sensor need to be mapped... Your boost controlled is out of control...

Misfiring on a diesel engine is strange. You have no spark plug. Only the injection timing controlled the ignition.
Do you have a bigger rail sensor? If yes, is it mapped?

First step: map all sensors correct!
If its done, make datalogs

Everything else does not make sense.

And the engine can a lot. With the right mods you can run 300hp...
 

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Discussion Starter #6
The map sensor need to be mapped... Your boost controlled is out of control...

Misfiring on a diesel engine is strange. You have no spark plug. Only the injection timing controlled the ignition.
Do you have a bigger rail sensor? If yes, is it mapped?

First step: map all sensors correct!
If its done, make datalogs

Everything else does not make sense.

And the engine can a lot. With the right mods you can run 300hp...
the misfiring/holding back is sorted now. It use to throw up codes for all sorts of things on the fuelling side of it hence why I replaced nearly every sensor and solenoid. To then find out it’s a broken wire on the maf loom 🤦🏻‍♂️
I didn’t realise the map sensor needs mapping in. I’ll swap it back over to the standard one for the moment then. The rail sensor is standard. I can’t find anything about upgrading the fuel system in the Vauxhall world for the 8v, this is why I’ve come here because I know the he Alfa shares the same engine pretty much and I’ve seen a few on YouTube running good power.
 

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Yeah, put the old map back in the car.

You have a 1800 bar map sensor. You can install a 2000 bar sensor, but i would prefer to run such high rail pressure. And with hybrid its not needed.
80mm maf should be a good choice.

If you have a bigger turbo in the future, you can install injectors with a bigger nozzle and a R80 or R85 fuel pump.

And biggest point should be the clutch in the future.
 

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Discussion Starter #8
Do you know which bigger injectors fit in these or can you get the standard injectors modified? I’ve got another set of standard injectors.
 

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😲 New sensors without remap is dangerous and inefficient. You can uninstall your original turbo 1749vm and install 1756 with all these mods and result will be poor driveability and anything broken soon. Dyno was low, obviously.

That engine is good for remap. Stock can do 160-170ps easy and 180+ with good maps. With your mods (after fixed remap) there are no problem to do 200ps.
 

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😲 New sensors without remap is dangerous and inefficient. You can uninstall your original turbo 1749vm and install 1756 with all these mods and result will be poor driveability and anything broken soon. Dyno was low, obviously.

That engine is good for remap. Stock can do 160-170ps easy and 180+ with good maps. With your mods (after fixed remap) there are no problem to do 200ps.
It was running 170bhp on the standard turbo before with a tuning box (good one not cheap crap).
I understand the risk with it not mapped correctly and I’m quite surprised I’ve not blown it up yet. Waiting this long as never my intention but like I said above with the previous fault I had it never ran right and the guy as unable to map it. All he managed to do was delete the egr properly and make sure it was fairly safe for the moment 🙈 I’ve been trying to take it easy and not floor it. 🙈🤭
I’ll stick the standard map sensor back in for the moment. If I can achieve 200bhp I would be more then happy. It’s going to spend most it’s life on track days once everything is sorted!
In the Vauxhall world information on upgrades and performance is near impossible to find!! I’ve had to work a lot of stuff out myself and it’s been trial and error.
 
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