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I have owned my car for a few months now...I sent it to fox valley and they went over it and said the noise was due to a bad turbo and it needs rebuilt. I told them to do both since the car is almost 12 yrs old with 34k miles. The noise is inconsistent and only at idle. The car is wicked fast so i do not think any internal problems. The car also has 200 cell cats and no mufler...so i sided with them because it made since that it was stalling out and the back pressure was making it spin again. I said as long as it fixes the noise i am happy...3k of turbo repair and still have the noise. They now say there is no back pressure because of having no muffler. I would believe this if it did it out of both sides. anyways i am looking at getting a stage 2 chip from p.u.k. and one of the reviews on the chip says it fixed his lean pop on trailing exhaust. I dont know if he means what i have or when you let off the throttle. I am thinking of buying a stock exhaust to see if that fixes it. Has anyone had this problem and if so was it do to the aftermarket exhaust ?
 

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anyways i am looking at getting a stage 2 chip from p.u.k. and one of the reviews on the chip says it fixed his lean pop on trailing exhaust. I dont know if he means what i have or when you let off the throttle. I am thinking of buying a stock exhaust to see if that fixes it.
He means when you let off the throttle. This is not entirely uncommon on very free-flowing cars (cat-less for instance, mine did this sometimes before the latest tune.) It's not a problem, either (unless the noise bothers you.)
 

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Discussion Starter #4
It only does it at idle...i get sick and tired of people asking why does it make that noise. I just tell them it is because of aftermarket exhaust. If they all do it at idle why just the passinger side.
 

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Almost all stock ECU V8's I've heard exhibit lean popping from time to time at idle and a trailing throttle lean pop. Lotus has never shared the fuel maps and decel settings with the world.
 

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Mine does it a ton more with the High flow cats ( 200 Cell ) both on idle and when letting off the throttle than stock but its always done it..
 

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I noticed mine improved after replacing the primary injectors but you can still hear it a little. More than that, when it is cold you hear the lifters knocking till it warms up. Scared me at first, it was so loud.
David Teitelbaum
 

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Discussion Starter #9
so what years are your lotus s and does it do it on passinger side only. I am looking at p.u.k. stage2 chip do you think it will help with the noise and is it worth the money. I also wonder at what boost level should one start thinking of intercoolers or water injection system.
 

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There are pages and pages of threads on increasing boost and adding intercoolers or water injection. Look at all the major Lotus esprit forums. The problem is achieving correct AFR. There are several "chips" that can be purchased and external boost controllers to increase the boost. But the OEM Lotus ECU will retard timing and and add fuel to cool the engine at these extended boost levels, reducing the potential gains and reducing the life of the CATs. It's all a matter of degrees, add to the mix that the OEM pistons are cast not forged and incresaing the boost willy nilly can be expensive. One must take a complete "systems approach" to increasing boost. I have not seen any dyno plots of increased boost and correct AFR (around 12.5:1 in power mode) for any of the after market chips.

Approach with caution.
 

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Discussion Starter #11
thank you wayne, i was just thinking of stage 1...factory boost overseas is not restricted like here in the usa. Some say this is a must have(stage 1 chip) for u.s. versions. For a couple dollars more you get same chip but with a boost controller or what ever you call it. for that what if i could turn up the boost someday once i get the twin intercoolers. I am looking at one that comes with an ice box. I bought the car for car shows and that is what i intend to do. But i would like a little more boost... at least the boost restrictions removed in gears 2-4. Just a side note i found out from lotus that my car is one of one (silver with red leather) so i intend to take very good care of her. Just do not want a corvette z06 to bet me.
 

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Everybody wants "just a little bit more". Pretty soon you get used to that and want more. It's a slippery slope. If you want more performance out of the car my suggestion is to spend it on the driver. Take a driving course and/or lose some extra weight. Anything you do to modify the car to "improve" performance is at the risk of longevity and reliability. If you think you will spend a lot of money modifying the car wait till you blow it up and have to repair it!!!!
David Teitelbaum
 

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Ok, it seems like the crackling/popping from the passenger side bank of cylinders is normal, as my 2000 v8 does the same thing. It starts a couple minutes after engine startup when the engine warms up a bit. Only when I back off throttle does the popping occur.
 

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Chiming in to say that my 2001 does the exact same thing on the passenger side as well. Guess there's no reason to chase after that if :tadts:
 

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My 99 pops a bit but on the drivers side. Cleaned the injectors and put new in plugs and wires and it made a little bit of a difference. Using ethanol free gas almost eliminated the trailing off pop...
 

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i get sick and tired of people asking why does it make that noise.
Maybe it's just me, but I kinda like a bit of popping on deceleration. Just like almost every race car or exotic that puts out a lot of power.

I just try to be mindful when I am driving near some of our local equestrian farms - don't want to spook any animals with the exceptionally loud ones!

Not my car, but check out the flames at about :15 secs in this video:
Lotus Esprit GT3 Exhaust flames - YouTube

Passenger side.
 

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What does that popping do to the life of factory V8 cats? I make an effort to limited the sometimes very loud popping on deceleration by pushing in the clutch and going to neutral if it's a long coast to a stop light. Not an ideal way to drive.
 

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What you're experiencing is normal to TURBO cars. This isn't even an issue of Lotus. Popping is due to excess fuel in the exhaust, exploding. I have a 3inch catless setup on my MR2 for example. It pops quite abit on decel and sometimes at idle.

As to why just the passenger side, depends on the way the exhaust is plummed. If that side has a shorter distance or run then it may just be a natural occurance. For my own car, my right tailpipe exhibits more popping/flames due to it being the natural route exhaust flow takes. Especially if you have unequal length manifold design.

I'd say your car is fine and if it annoys you then look into leaning it out more, causing less excess fuel in the exhaust. Don't know for the Esprit as to what your aftermarket ECU options are but it's probably the only way. Many stock turbo cars run rich for saftey. Enjoy!
 
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