Flames from exaust GT3

[Cos]

Hi Guys.

I have a '98 GT3. I live in Cyprus. When I bought the car just over a year ago, it had a twin exaust, which looks rather good and I have kept. It must be custom, and looks similar to the stock V8 exaust, having just one big center box but with just one entry.

Since then, I have, changed the injectors to RC ones from PUK, fitted a decat pipe, fitted a bailey dump valve and also fitted an electric chargecooler pump.

Recently, I went with a few mates for a rather high speed trip up some mountain roads in Cyprus. A ferrari 355, a Porsche 911, a Masserati 3000 and a Porsche boxter. One of the best driving days I have ever had, and very scary too. Most of the roads dont have any barriers, and the drops are huge. When we stopped off for a coffee and a smoke, my mates told me that they saw some exaust flames coming from both exaust when I changed down gears or accelerated very hard. There was also soot in both exaust pipes. The exaust also makes some popping noises whenever I change down gears.

I have run freescan, and all the readings are normal with no faults. Does anyone know if this is acceptable, or if I ought to do something about it?

Regards

Cos

[aerobat]

I'd consider it the equivalent to a bumper sticker that says: "If you can read this, you're too close" !!

I can only hope it looks this good :

[kyliesmith.com]

^ ^ ^^

Noice hehe likey a lot!!!

Constatine try doing a search in this part of the forum, its talked about frequently, some would argue they all do that and the tuners would say otherwise.

Get your mate to take some pics oh and a sound file for next time eh!!!

[Cos]

I have no idea idea what it looks like. I did ask, and my mates told me that the flames were very bright, even though it was a hot sunny day.

I am thinking of fixing my camcorder facing forwards to the Masseratti, which will no doubt be behind me again.

Seriously, I dont mind the flames, but I am concerned if this might cause problems.

I am thinking of fitting the PUK 280BHP GT3 chip, but am not sure if this would be safe for the engine and gearbox.

Does anyone have any flaming experience?

Regards

Cos

[greekmix]

Costantine , flames or backfire are always good for photos however that does not mean the car is running 100%

Many people put many tricks on their cars thinking because it worked for others thinking it should also work for them.

I have learn from my experiment on my car and I am so lucky I took the car on the dyno before I made any changes to get a reference point as to where I am starting from.

so far not all the adjustments we did proved to be what the suppliers have claimed... THANK GOD TO THE DYNO RUNS.

So I would suggest to run it on a good dyno in your area who provide a huge fun for air flow.

I must also say that the esprit behaves some what different on the dyno due to air flow but you need to be smart with tempretures before you take a reading and you must run freescan while on it.

If you need more input on this please contact me for help on my email info@lotusesprit.com.au

Xereto apo makria!!

Tony

[Bibs]

Not sure how that helps Tony, makes no sense to me.

From what I've researched, the Esprit with EFI runs very rich at high boost, the reason for this being the excess fuel helps to keep the piston crowns cool. This excess fuel then travels past your turbo, which at high boost can be in excess of 1000 degrees C. Unburnt fuel plus hot turbo equals flames. Having a decat also means that these flames no longer travel through the cat which is why they now make it out of your exhaust pipes

[Kimbers]

As Bibs says. Don't worry about it. The only thing you are doing is burning a little more fuel and many members on here, who have de-Cat'd their cars experience the same.

[karluk29]

the reply you need is ^^^^^, its a normal thing.

the reply you need from me is,,,,,,,,,IT LOOKS REALLY COOL!!!

fit chip 11 from marcus, i have chip 10 and i want chip 11, the difference will (I PROMISE)

blow you away, the plant the accelerator and you feel the turbo come in as usual then suddenly

oh my god, its like another turbo comes in aswell. changes the car to another level.

(oh and you will destroy your mates cars hands down, i can beat a 911 off the line (timed)

with my car and thats chip 10 and at the time i had a faulty chragecooler, but i suppose it

depends if its a insane pork turbo crazy 3.8sec version)

[Jonathan]

Sorry to disagree but depending how frequent it's happening it's not something to ignore.

Whats happening is unburned fuel is exploding in the exhaust somewhere which increase the back pressure on the engine significantly.

In severe cases you can have strain on the turbine and the valves. As Karl says it's fun, but if it is occuring all the time I would have it looked at.

Best case scenario is you might blow a weld on the exhaust - I have seen back boxes ripped to shreds (and the boot space by the flying shrapnel) from one too many post detonations.

The reason why I found it happened was de-restricted / de-cat exhausts (look at flame outs, pretty much everyone with non-standard exhuasts have them) becuase on run down the pulses are not cleared from the pipes properly (mainly due to larger pipes, or more of them !), with your foot off the accelerator the exhaust pressure drops, ambient air can get in and thats what detonates the fuel (as Bibs says, temperature and fuel, but you also need oxygen/air) thats why the Larini exhaust I have on mine is made so that one pipe favours flow more than the other - to maintain pressure in the exhuast on run down so there is less chance the air can get into the pipes and detonate.

It's tricky to explain, there is a good site about exhuast pulses, back presusre, turbos and so on somewhere which explains it well with diagrams and why stuffing the biggest hole on the end of a turbo'd exhaust is not a clever idea due to exhuats turbulance and increased back pressure (on the turbo, not so much the engine).

It not totally un-aviodable - I can get my car to do it if I try hard enough, but certainly if it's a regular occurance you might need a small restrictor on the exhuast, you could leave it banging away but if it's anything like the kids rolling up and down my road they only generate bad feeling from other road users etc.

Edited September 29, 2008 by Jonathan

[DanR]

Some good info here:

http://www.nsxprime.com/FAQ/Miscellaneous/exhausttheory.htm

[OwenGT3]

Stills from the video I done following my car, I was driving my mates Elise.

Doesn't do it now the cat is fitted.

Owen

Edited September 29, 2008 by OwenGT3

[t70]

It is because, as bibs said, the ecu runs extremely rich. Now, Running that rich, in my opinion, is not necessary. I realize that lotus thinks it is, but I disagree, the chargecooler is there to keep temps down, running that rich causes other problems (like the burnt exhaust valves commonly found on cylinder 3 and 4) The backfiring is cool etc... but realistically, it isn't that healthy. I love the sound of it, and in the Larini exhaust, the pressure can exit from both pipes, so the likelyhood of a pulse doing damage to the turbo vanes is small.

[Jonathan]

On the turbo it's more of an issue of stalling - we spend

Edited September 30, 2008 by Jonathan

[jpspeedy]

has anyone did their own de-cat by just knocking the insides out of the cat-pipe? I thinks about it. jim

[Bibs]

Mine did that itself over 19 years!

[SE Owner :-D]

Mine has stopped doing flames since big turbo - now replaced with extreme speeds!

[SE Owner :-D]

Mine has stopped doing flames since big turbo - now replaced with extreme speeds!