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Thread: Fuego X File

  1. #1
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    Default Fuego X File

    I recently brought a set of tubular extractors from French Connection and I got them fitted to the old Fuego on Friday.

    While I was at it, I got 1 of the middle mufflers removed (the one that sits just behind the gearbox) replaced with a piece of pipe instead to free up the system a bit.

    The good news is the car feels noticebly smoother and it spins a little better up top, but it's also alot less boomy at 3000 rpm (all of the Fuego's I've driven seem to have an annoying resonance at 3000 rpm).

    What I cant work out, is that the car is now significantly QUIETER inside (not sure about from the outside) than it was before

    How the hell can fitting extractors and removing a muffler make a car quieter???

    Any ideas?

    I was thinking it may have been a harmonic resonance from the manifold (I had a Pug 505 manifold fitted, but that sounded and felt the same as the original manifold, minus the leaking noise from the usual crack).

    The extractors have equal length runners (quite long) and are the normal 4 cylinder 4-2-1 style.

    I am not complaining mind you, as this has fixed one of the only things I dislike about the Fuego... not complaining, just perplexed..

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    Any got a reasonable explanation or had a similar experience?

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    Guru davemcbean's Avatar
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    Richard,

    That's great news! This may help alot of 505 owners solve their booming problems and also make their 2.2s rev better.

    What are the diameters and primary and secondary lengths of the pipes you're using? I'd like to stick those specs on my 504/505 website.

    I know that Graham Wallis is building up a 505 rally car using the 2.2 GTI engine with Megasquirt EFI. He could probably benefit from copying the important dimensions of your extractors.

    Dave
    NZ Fleet
    1976 504 Ti
    1984 205 GT twin carb
    1991 205 SI 1.6GTI motor
    1994 106 Xsi
    1996 Mondeo V6
    Aus Fleet
    1955 203C
    1997 Civic Cxi (great allrounder- revy, flexible, nimble, comfortable , economical, simple and durable )

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    I'll take a photo and measure them up as best I can...

    I wasn't sure if it was a problem with the Dourvin 4 powered Pugs, I thought it might have just been the way in which the engine was mounted in a Fuego (ie a vibration resonance)

    I should have taken photos before I put them in...

  4. #4
    Guru davemcbean's Avatar
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    Quote Originally Posted by mistareno
    I'll take a photo and measure them up as best I can...

    I wasn't sure if it was a problem with the Dourvin 4 powered Pugs,
    Thanks!.

    Yes, I gather it is actually more of a problem in the Pugs than the Renaults. Peugeot spent alot of time trying to eliminate this and eventually went for a more restrictive exhaust system on the later series 2 505s, with multiple resonators, etc. A free flowing system which accomplishes most of the same outcome would be a great thing.

    Dave
    NZ Fleet
    1976 504 Ti
    1984 205 GT twin carb
    1991 205 SI 1.6GTI motor
    1994 106 Xsi
    1996 Mondeo V6
    Aus Fleet
    1955 203C
    1997 Civic Cxi (great allrounder- revy, flexible, nimble, comfortable , economical, simple and durable )

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    1000+ Posts jo proffi's Avatar
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    What are your impressions about both pro's and cons of fitting extractors to the fuego.I am considering doing the same.
    cheers ,Jo

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    Quote Originally Posted by jo proffi
    What are your impressions about both pro's and cons of fitting extractors to the fuego.I am considering doing the same.
    cheers ,Jo
    Pros:

    Performance - Extractors will generally breath a little better and produce more power at high RPM - sometimes at the expense of bottom end torque..not really an issue with a motor that is so torque biased as the Dourvin 4

    Weight - They usually weigh a little less than a cast Iron manifold..

    Noise - May produce a different exhaust note and Fuego manifolds always crack and sound shite so it fixes that problem..

    Booming at 3000rpm - It certainly fixed it on mine but it was an unexpected advantage.

    Cons:

    Originality lost

    Cost - may be very hard to find a set, or very expensive to have a set made up from scratch.

    Polloution equipment - Some extractors will not have all the conections for the factory emission equipment

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    [

    I'm surprised that you say the Douvrin motor is torque biased, compared with the Peugeot XN motors they don't seem to have anything below 3,500.
    Trouble is that most STIs (K jetronic) don't have anything above 5000 also!
    I am using a GTI motor, these do rev at least, although the bottom end torque is even worse. Not really a good engine but I guess it should be better than the 45 year old XN1 and the last time I fitted one of these the handling was significantly improved. The engine is lighter, shorter and sits an inch further back than the XN.
    Hopefully the Megasquirt setup will pick up some low end power. I have recieved my megasquirt kit and am assembling it at the moment, had to go and buy some ready made glasses though, they sure make electronics small these days!

    Graham Wallis

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    Quote Originally Posted by GRAHAM WALLIS
    [
    I'm surprised that you say the Douvrin motor is torque biased, compared with the Peugeot XN motors they don't seem to have anything below 3,500.
    I have never driven an XN powered 504/5 but from what I have been told, they are like a light truck engine (no offence intended) in that they have heaps of torque down low, but anything over 4000 rpm is a waste of time and petrol.

    Remember the Fuego weighs almost half a tonne less than a 505 and has a pretty close bunch of ratios. A 1.5 tonne 505 might be a different kettle of fish...

    A fuego will pull cleanly from virtually idle (I quite often take off in second gear and keep up with traffic easily) and produce good useable torque from about 2000 rpm.

    Compared to an XN motor they may be flat down low, but compared to most engines they are a reasonable compromise of low down torque and sporty power...pity the Australian version only has an 8.5:1 compression ratio

  9. #9
    1000+ Posts jo proffi's Avatar
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    Anyone know where ther are any extractors lying around?

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    Quote Originally Posted by mistareno
    I have never driven an XN powered 504/5 but from what I have been told, they are like a light truck engine (no offence intended) in that they have heaps of torque down low, but anything over 4000 rpm is a waste of time and petrol.

    Remember the Fuego weighs almost half a tonne less than a 505 and has a pretty close bunch of ratios. A 1.5 tonne 505 might be a different kettle of fish...

    A fuego will pull cleanly from virtually idle (I quite often take off in second gear and keep up with traffic easily) and produce good useable torque from about 2000 rpm.

    Compared to an XN motor they may be flat down low, but compared to most engines they are a reasonable compromise of low down torque and sporty power...pity the Australian version only has an 8.5:1 compression ratio
    My XN1 will rev cleanly and quickly to 6000 RPM and the 505 weighs a bit over 1200 kg. However, within its rev range the ZDJL GTI has 30% more power than the XN1
    The XN2 motors have almost the same performance in the 504 TI but I have given up on these after selling my 404 the other day, the mixture was varying all over the place, a brand new one would be nice though.

    Graham

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    Quote Originally Posted by mistareno
    I have never driven an XN powered 504/5 but from what I have been told, they are like a light truck engine (no offence intended) in that they have heaps of torque down low, but anything over 4000 rpm is a waste of time and petrol.:
    That only applies to the twin carb 76-78 version and the 75% of the rest which have the accerator cable poorly adjusted so that the second throat doesn't open properly.

    The XN1 motors which I've had have always revved cleanly to 6000rpm before noticeably dropping in power.

    Contrary to Graham's experience, the Douvrin 2.2 STI motor I had had heaps of grunt down low (like a truck engine ), but was breathless above 4000rpm compared with my XN1 motors. I sold the STI motor and stuck an XN1 in it. One Fuego I've driven was similar to the STI, the other reved as well as the XN1.

    I really believe that the Douvrin is best as a 2 litre. In order to turn such a compact engine into a 2.2 litre, they had to do some dodgy things in regards to conrod length to stroke ratio. I guess this could be solved with modern short lightweight pistons and some longer conrods.

    Dave
    Last edited by davemcbean; 17th August 2004 at 11:21 AM.
    NZ Fleet
    1976 504 Ti
    1984 205 GT twin carb
    1991 205 SI 1.6GTI motor
    1994 106 Xsi
    1996 Mondeo V6
    Aus Fleet
    1955 203C
    1997 Civic Cxi (great allrounder- revy, flexible, nimble, comfortable , economical, simple and durable )

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