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Old 31-05-2006   #1
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Bravo HGT - Low Performance after fitting new exhaust

Hello..

my first post

I have a bravo hgt in which run like a dream, i decided to get a new exhaust system, sportex, full system up to the CAT...
since fitted the perfomance has lowered.. at 5-5.5k revs its like i'm slightly deperessing the accelerator, and in 5th gear it will not get passed 5.5k, although it did with the standard exhaust, .. it would carry on into the red with no problem at all.

Does anyone know what this could be?
The exhaust is a straight through silencer, thicker pipe and after complaining to the supplier they do not honestly know what the problem is , they sell 3-4 of these to bravo owners a month aparently.

Any help would be greatly appreciated.

Reply from supplier:0-

"We supply this exhaust a 3 or 4 times a month for the past couple of years and have had only good feedback from ebay buyers and retail customers in our shop. I contacted the owner of Fast Fiat the UK's leading mailorder Fiat specialist who also supply Sportex they too have only good response to this system. We don't understand the problem you report. The system has straight through silencers and is less restrictive than the standard. The only thing I can think of is that the cat has been damaged when fitting the exhaust or somthing on the air intake side is causing a restriction? "
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Old 31-05-2006   #2
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Re: Bravo HGT - Low Performance after fitting new exhaust

try disconnecting the battery for an hour and reconnecting to reset the ECU.
it could be a slight blockage in the pipe but try the ECU 1st
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Old 01-06-2006   #3
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Re: Bravo HGT - Low Performance after fitting new exhaust

resetting the ecu sounds like a brilliant idea.

Will give it a go and let you know.

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Old 01-06-2006   #4
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Re: Bravo HGT - Low Performance after fitting new exhaust

when i made a striaght through pipe for my 1.6 bravo it really didnt like it at all, putting the standard exhaust back on made it much quicker, that was because my straight through pipe didnt provide enough back pressure. you could have the same problem but i think sportex would know if their design affected performance this much, then again sportex are a budget company so they probably dont test their designs before they sell them.

the other possiblity is that the lambda sensor was disturbed during the fitting of your new exhaust. maybe the wire has been damaged or pulled of at either end, i'd check the wiring for the sensor. also its possible that during fitting the exhaust flexi joint was damaged causing a leak and loss of back pressure, i'd check the whole exhaust for leaks.

failing that you could always stick the original exhaust back on, if it fixes the problem get onto trading and standards and say the exhaust isnt as described or fit for purpose. then draft a letter to sportex and see if you can get a refund or something, its surprising what you can get if you kick up a fuss. i'd be pist off if i paid for an exhaust that made my car worse, even if it was a cheapy sportex one.
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Old 01-06-2006   #5
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Re: Bravo HGT - Low Performance after fitting new exhaust

Thank you very much for your advice.

the feel is as if, the amount of mixture of fuel or air is cut, OR there is maybe a blockage.

After 3.5k revs, the exhaust is no longer loud and sounds like the original, which i guess is normal, when it reaches the point where it slows down (5k revs) it does sound like there isn't enough room for all the gases to escape and makes a shhhh in sound maybe a small leak? (would that cause this?)... it feels just the same at low rpms as it did with the standard.

I have disconnected the battery, will see if it makes the sound at the same rpms. I understand it will feel more responsive at low rpms.

If that doesn't sort it, i suspect it is a physical problem of either a blockage or the back pressure you mentioned.
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Old 01-06-2006   #6
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Re: Bravo HGT - Low Performance after fitting new exhaust

Reseting the ECU didn't work, thanks for that tho.. i suspect it will probaly do it good being reset.
Still getting the same noise and cut in performance.
Will take it into the garage on monday, see if they can see anything...
What is the chance of the CAT being damaged fitting the exhaust slim or high.. the garage is well known and recommended, big and experienced.
I actually watched them fit the exhaust, was very simple.. if i had ramps i'd have done it myself.

Or are the supplier of the exhaust guessing randomily.. e.g. air intake or Cat damaged.
I can tell you that it worked perfectly with the old exhaust which was a little rusty and needed replacing anyway, which is why i bought this one as it wasn't that much more expensive.
200 total - and 30 to fit at the garage which took minutes.

There was a bit of smoke coming from the exhaust after it was run, but stopped after a few mins... i was told this was because its new.

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Old 01-06-2006   #7
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Re: Bravo HGT - Low Performance after fitting new exhaust

tbh its very strange,i wonder if perhaps the lambda has been damged.really weird one.
do you still have the old exhaust to swap back?
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Old 02-06-2006   #8
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Re: Bravo HGT - Low Performance after fitting new exhaust

no.. the old exhaust was rusting bad..
I don't think it is anything electrical or sensor wise.
The sound and feel is like a physical exhaust problem, as if it is all in the exhaust system..(note, it actually sounds like its happening at lower revs now that i reset the ecu, possibly due to more mixture = more gases)...
Its like it can't all escape, theres to much for the exhaust to handle at those revs. Yet the piping is the same diameter if not fatter. Its a twin design like aboveat the end.
Could this lower in back pressure be the cause?
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Old 02-06-2006   #9
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Re: Bravo HGT - Low Performance after fitting new exhaust

lower back pressure tends to push the power up the rev range not stifle it.
think you need to remove the system to check im afraid
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Old 02-06-2006   #10
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Re: Bravo HGT - Low Performance after fitting new exhaust

What should i get them to look for? Blockage?
Can they tell if the Cat is damaged? How could they damage the CAT installing an exhaust?
I watched and didn't see any problems, was very very simple, unbolt everything from the cat to the back box, and put this one in its place.
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Old 02-06-2006   #11
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Re: Bravo HGT - Low Performance after fitting new exhaust

to damage the cat during fitting you'd have to be pretty thick and bloody careless, i cant think how it could get damaged unless they didnt have the rubbers connected and the cat took all the strain when they let go of it, but that would damage the flexi joint not the cat, and it would take a completely numb fool to do that, i still suggest the lambda sensor could be the problem, its not to hard to believe that they may have caught the wire, follow the white wire into the engine bay, its connector sits under a small black plastic cover right in the centre of the engine bay at the back near the windscreen, see if its still connected and in the right place.
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Old 02-06-2006   #12
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Re: Bravo HGT - Low Performance after fitting new exhaust

just been to the garage.. put on ramps.. no visible signs at all.. all looks perfect, gave it all a kncok and swing.. took the exhaust off, no blockage. Nothing wrong with lamda (or whatver it is) the garage boss said its running like a dream there is no problem apart from this lower in performance.... one of the mechanics there is an enthusiast, and has a saxo vts, bored out and all the works 170+ bhp, he said it will probably just because its a cheap exhaust as he has heard the same story.

We went for a drive with the boss to his house (to have a look at some computer trouble hes got, as i fix PCs as my job and he is a regular customer and a friend, he fixes all my dads Pizza Vans)... and he drove... wow isn't it fast when your in the passenger lol.

Same problem.

The car is in top shape... only problem is its done 60k miles without a cam belt change.

It revs fine in neutral up to the red, i can feel the difference in in 1st, 2nd, 3rd, and visibly i can see the differentce on the rev counter in 4th and 5th, struggles to get past 5k in 4th, and won't do it in 5th.


Do you think i rolling road test can tell us anything?

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Old 02-06-2006   #13
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Re: Bravo HGT - Low Performance after fitting new exhaust

A RR graph would give you an indication.

If I got it right you have a twin exit. This could be half your problems puls some poor and/or reverse welds.
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Old 02-06-2006   #14
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Re: Bravo HGT - Low Performance after fitting new exhaust

Quote Originally Posted by jug
sportex are a budget company so they probably dont test their designs before they sell them.
you get what you pay for some times, and this isnt the first time ive seen a "sports" exhaust that reduces performance. get a standard exhaust and replace the backbox by chopping the standard one off and replacing it with an aftermarket one, that rarely causes problems.
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Old 02-06-2006   #15
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Re: Bravo HGT - Low Performance after fitting new exhaust

Quote Originally Posted by Oldschool
A RR graph would give you an indication.

If I got it right you have a twin exit. This could be half your problems puls some poor and/or reverse welds.
off topic but hows the move going?
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