Peugeot 106 1.3 Rallye intake system

Competition engines and ancillaries - general discussion
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romilos
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Peugeot 106 1.3 Rallye intake system

Post by romilos »

Hi!

I have a Peugeot 106 1.3 Rallye

I'm trying to find out if there is a way to calculate somehow the volume of the air intake box, the length of the pipe from the throttle body to the box and the diameter for that pipe.

I'm now running with the OEM air box which is modified so it can draw cold air from the front. The pipe length-diameter are OEM.

If I make another box is the place critical or not?
What about its volume?
Does the airbox work like the expansion box in the exhaust?
romilos
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Post by romilos »

here is my intake box

Image

it is 30cm wide

i ve insulated it with aluminium tape.

A jr air filter is installed.

It is sucking air from the front if the car.

the pipe is 60mm inside diameter

and apr 24cm long
Testament
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Post by Testament »

The volume of the airbox is not as important as the volume of the plenum, its more to do with fitting a large filter to minimise the restriction and having a shape that will not cause restriction either.

As for tuning your intake pipe you can take the length of the pipe and the speed of sound to determine its tuned frequency and harmonics to see if there is any effective pressure waves to be utilised at a realistic rpm. This will only give you a very very rough idea and you will have to try various lengths of pipe around what you calculate to see what is optimum, if it does make any discernable difference.
romilos
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Post by romilos »

Testament wrote:The volume of the airbox is not as important as the volume of the plenum, its more to do with fitting a large filter to minimise the restriction and having a shape that will not cause restriction either.

.
I see...
Then we must see the air filter surface...

If we change the surface tha the box sucks air do we change the air that the engine uses?

For me a gain 2-3% with that tune would be just fine!
do u think i can have that gain?
romilos
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Post by romilos »

Image

Τhis is the best i can have for the moment.
The plenum is aluminium
I cannot take a good pic the pipes that lead from the plenum to the head.
Their length is apr 20cm maybe litle more (25)
Guy Croft
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Post by Guy Croft »

Hello Romilos,

eventually I have time to reply, thank you for posting the photos, now all is clear.

Keeping it simple, we need to be aware that the cylinder filling is controlled by two main things, the pressure waves between the valve throat and the open end of the inlet tract and the momentum of the air mass in this tract. The critical inlet length for optimum pressure wave effects (that enhance filling) is the chord length (centre axis distance) of the inlet tract from the back of the inlet valve to the open end of the pipe at atmospheric pressure ie: the air box. This is quite long. This is the 'open end' that causes the first and most powerful wave - a negative one when the valve opens, to be reflected as a beneficial pressure wave.

You should not change this chord length on that engine as it is matched to the standard cams and exhaust manifold and, on a modern engine, if you alter it, it will definitely not produce a better 'area under the torque curve/driveability' characteristic. You cannot alter much and achieve a gain on the standard engine.
For example, with modern engines, a non OE exhaust manifold is as likely to lose as gain 'overall' power. Sure, more peak power may showup on a rolling road test, but it will not be 'more area under the torque curve', and unless accurate before and after torque curves are overlaid you might think you've got more overall power, but you haven't..

The only mod you could do with standard cams and inlet tract, exhaust manifold is gasflow the head and inlet manifold, this will give more momentum - mass flow - without disturbing the relationship between tract length and pressure waves.

If you change the ex manifold, cam (primary components) the lengths will not be correct any more, although you might be lucky and end up with a good compromise.

GC
romilos
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Post by romilos »

Ι see...

I have not OEM cam (it seems that the exhaust is more aggressive - I believe it is for group N 1.3 Rallye , following the homologation)

CR from 10,2:1 to 11:1

We have done some work to the intake-exhaust ports of the head.
free (de-cat) exhaust and Peugeot Sport ecu.

I think you are very right talking about the area under the torque curve!!!

I have insulated the air box and open the surface that sucks air, from 28sqcm to 60sqcm(I've cut the box in the front and now it has a gap, 30cm long and 2cm wide). Do u think that is any reason to test other bigger surfaces or I wont change the air flow at the pipe ?

My engine is model 1995, do you think it's modern? (is it following the "rule" you said? They say that the OEM exhaust manifold of the Rallye models is very very good and worthless to change it. Actually you are saying the same think!

So anything from a free flow air filter and a place to suck cold air, is worthless...(length of the pipe and diameter)


Guy thank you for your time!!
simon-spanner
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Post by simon-spanner »

i used to own one of these
mine ran stock rallye cam, ported head, 11-1 compression
i ran a k&N cone filter in the stock location with some ducting to prevent it sucking in hot air from the radiator
the stock exhaust manifold is very good as is the stock exhaust- i ran backpressure tests with and without the cat and found no increase in power
when the stock exhaust eventually rotted away i replaced it with a grp a magnex system but didnt fit the cat replacement pipe

mine ran about 120bhp and 90ish lb/ft of torque

great little car- i miss it terribly
romilos
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Post by romilos »

simon-spanner wrote: I used to own one of these
mine ran stock Rallye cam, ported head, 11-1 compression
I ran a k&N cone filter in the stock location with some ducting to prevent it sucking in hot air from the radiator.
The stock exhaust manifold is very good - as is the stock exhaust - I ran backpressure tests with and without the cat and found no increase in power. When the stock exhaust eventually rotted away I replaced it with a grp a Magnex system but didnt fit the cat replacement pipe

Mine ran about 120bhp and 90ish lb/ft of torque, great little car- I miss it terribly
Yes is very good for 1300cc!!!

You think with the K&N filter is better than the OEM air box??

So the OEM cat is very very good! I now have at the exhaust and expansion box and then a straight-thru muffler! Do you remember gains from the new exhaust?

When you say Rallye cam do you mean ps cams?

Mine is approx 112-115 hp
simon-spanner
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Post by simon-spanner »

i didnt dyno the car with individual mods- rather when i sold it, the bloke i sold it to wanted a power run

the cam was the original fitment from peugeot
G&G Motorsport

Post by G&G Motorsport »

Ok so I found the thread and have had a read.

We have run a S1 Rallye for a number of years now, although it now has a 1.6 8 valve engine in.

1 thing I have noticed with this particular unit is the intake temps, and you do the right thing trying to cut them down by lagging the pipe work.
Another thing we have done is make a hole in the front bumber where the number plate would origanaly fit, to aid cooling.

The OE manifolds are very good although the steeper motor does give bother.
romilos
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Post by romilos »

I didnt dyno the car with individual mods- rather when I sold it, the bloke I sold it to wanted a power run

the cam was the original fitment from peugeot
ok!:)

Another thig we have done is make a hole in the front bumber where the number plate would origanaly fit, to aid cooling.
aha, with that u had lower coolant temps?

The OE manifolds are very good although the steeper motor does give bother.
What is a "steeper motor"?
U mean a not oem motor?


U had the oem air box at your s1?
I have put the 1.3 rallye motor at a s2
(it was 1.1l)
Christopher_205Rallye
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Post by Christopher_205Rallye »

Romilios,

This picture may be useful to you.

The car is a the same as yours series one 106 Rallye 1294cc TU2J2.

He is using a Cup intake designed for the 106 Gti (Phase 2) with some modifications.

This car produced good power but it has a 1,6 conversion also. SO i'm afraid I cannot tell the positive or negative effect of this modification alone..

Th cup intake house has a come filter hidden inside. Its basically a copy of the peugeot sport one and should be easliy available




Image
romilos
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Post by romilos »

I have a similar intake (a little bit less volume)
It didn t work so well at high rpm...
In the middle rpm (until 5000rpm) is better.
We have done on road tests with vbox2

You mean that you have the head from the 1.3 and the block of 1.6 ?
I would like to test an intake like that but with bigger volume than mine.
Christopher_205Rallye
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Post by Christopher_205Rallye »

You mean that you have the head from the 1.3 and the block of 1.6 ?
I would like to test an intake like that but with bigger volume than mine.
Here is another picture of the cup air housingshowing the components

Image

The car used to belong to my friend. It is a phase 1 Rallye (1,3) but he has transplanted the whole TU5 engine from a Phase 2 (1,6).

To my knowledge the 1,3 cylinder head and 1,6 cylinder head are the same. However the 1,3 has believed to have a longer duration camshaft.

I sent thefull spec in english and pictures of this engine in a PM :-)
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