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R

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Discussion Starter #1
Hi, need your help?

1) how do you measure the air intake? from airflow meter outward to the begining of the tube?

2) Is this right? Shorter air intake = more low end torque

I am desperate to end the flat spot on my 8v, 1.8 at low end.

Thanks


Thanks
 
M

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Discussion Starter #2
Not true I'm afraid.
The length of intake etc is really a compromise. All to do with "pulse" tuning. I've posted about it in the tech section before.

My 1.8litre 8v had a flat spot just as you pull away and a few others, even 16v owners have complained of this.
Mine is fine now, sorted by a combination of fuel injector cleaner, new plugs and leads. Don't know which actually sorted it, or if it was indeed the combination.
 
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Discussion Starter #3
generally speaking, the longer the inlet track, the less bhp & more torque you can get if it's all tuned correctly, though as Marlon says, it's pretty in-depth stuff if you don't want to just fit different kit to see how it goes.

A
 

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In a really basic, vague kind of description, you need a long pipe for low down torque and a short one for go at the top end. Hence more modern cars with dual length inlet tracts. Like Marlon says, the rest of us are left with a compromise.

If you mess with it to sort one problem, you'll create another. Luckily for you, the designers at Alfa did all of the work for you.
 
M

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Discussion Starter #5
As said above, the shorter intake will give a better top end. I've experimented with induction kits and intake length. The best overall performance was gained (in my opinion) using the original airbox and a free flow panel filter.
I still suggest that you look at the basics like - is your air filter blocked ???
I modified my airbox by cutting away the bottom front quarter (leaving the lip to support the filter) and routing a cold air feed from the front valance to the whole.
I had already sorted my flat spot before doing this.
It is better to find the root of the problem rather than try and mask it.
 
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Discussion Starter #6
fade2grey:
generally speaking, the longer the inlet track, the less bhp & more torque you can get if it's all tuned correctly, though as Marlon says, it's pretty in-depth stuff if you don't want to just fit different kit to see how it goes.

A
Which all goes out the window when you stick a turbo in the way, then you are dealing with compressed air not air at less than 1 bar. Which makes it easier for us q4 boys, that reminds me I really ought to sort out the inlet on the track car!!

Steve
 
R

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Discussion Starter #7
Thanks guys - Marlon, fade2grey, richward, Steve abt the length thingy.

On tuning, checking Marlon's pulse tuning.

Meantime, touching on the life line,
1) Fuel Injector Cleaner - what do you use? since its tested and the result is good, would like to try.
2) Spark Plugs - am currently using Goldenlodge, previously Bosch Superfour.
3) Spark Plugs Wire - replacement, which brand do you recommmend for an upgrade.

About my air intake set up, using the original with Novitec panel filter - cleaned and oiled. Currently, routing the pipe from the box down towards the opening next to the fog light and putting a heat shield cover over the exhaust manifold. Any good?

Regards
rooi
 
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Discussion Starter #8
Pulse tuning - interesting stuff, whats the diff btwn the 16v, 8v and Silverstone's inlet manifold?
 
M

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Discussion Starter #9
The 8v and Silverstone are the same. Not sure what a 16v inlet looks like.
Your airbox setup is fine, similair to what I have.
I use Golden Lodge plugs with Champion Triple Sillicon leads.
Injector cleaner - you could use any off the shelf one or.................300mL of parrafin/kerosene to a full tank of petrol. Depending on how dirty the lines/injectors are you may have to do it a couple of times. Then repeat every 3000 miles (5000km)
 
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Thanks, will try.

Abt the Champion spark plug wire, do you need to modify to fit well into our 8v?

regards
rooi
 
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Discussion Starter #11
No the leads are designed for the car and come as a set of 8. :)
 

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Rooi

I did exactly the same setup on my 2.o 16 V. It does make a diffwerence, but you may find that the car will now "overfuel" at low RPM. I had my ECU remapped and gained about 16 BHP with the whole conversion
 
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Discussion Starter #13
As Steve says: It's much easier with a turbo, something to blow the air in regardless!

I'd stick with a standard air box and a good panel filter. Be careful to make sure that you have a effective water trap, if you ditch the standard box, you wouldn't want water in the combustion chambers, it doesn't compress like gas!

On a road car the gains are minimal at the best if at all. You could end up making your car go slower and use more fuel is you're not careful.
 
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Discussion Starter #15
Changes to the inlet side of the engine, i.e amount of air coming into the engine due to a change in filter type should not make a difference to the engine management as this is controlled by the airflow meter, length of inlet tract will make a difference due to the pulsing nature of the airflow.
However you ought to be careful when sticking very free flowing filters on cars as firstly they don't filter as much out of the air, and secondly its quite common on GTV's especially the 3 litre that when a sports filter and inlet pipe (without the resonater) is fitted the airflow meter has a habit of failing. In my view this is due to the very rapid changes in airflow over it which is normally damped down by the resonater box and standard filter.
 

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Don't forget cold air equates to more power than hot air. So the routing of the intake to elliminate hot air from the engine is another factor to take account of. As others have found I agree with the replacement panel filter in the stock system a good compromise, plus it does'nt affect insurance.

Phil
 
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