488 CEL

I have recently fitted capristo valved sports exhaust that deletes rear silencer but retains standard cats, now have a check engine light that relates to over boosting turbo pressures, any advice much appreciated.

 

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Have you contacted Capristo? I believe they sell a piggyback performance module that might help with the issue. If you look at the dyno printout on the website for the module, torque and hp numbers would suggest the tune is harnessing overboost and allowing for a flatter torque curve and not letting it drop. I'm assuming the module has parameters for tricking the ecu and not seeing the constant overboost.

Also checking and making sure your vacuum lines are connected properly is a must after swapping over the exhaust.

 

Good advice. Back in the day, when we were overboosting Jap engines, we would adjust springs in the wastegate to boost more or less. We'd also use boost controllers in the vacuum lines, which was a more elegant solution.

I'm surprised in this day & age with all the electronics that Ferrari have on their contemporary engines, that it's even possible to overboost.

 

I agree, although when it comes to such high levels of factory performance pushing the envelope, components such as waste-gate size or capacities depend on how much further the factory foresees their engines being tuned/modified.

Turbocharging hasn't changed much over the years just a little more refined with smaller more efficient compressors along with the use of variable valve timing (some manufacturers exploring the possibility of variable stroke and compression)-I believe turbocharging will always be a brutal way of inducting an engine, not to say it isn't fun or efficient!

 

CEL erased with scanner, code P0299, under boost, all hoses/lines intact, worked the car hard and no more light issues. Many thanks for your advice, also to chris at scuderia systems here in the uk, they are the capristo authorised distributor. This sounds awesome, really pops and crackles, not quite at N/A levels but much better than stock exhaust.

 

Ahh... well the term of overboost has changed my friend...

Overboost back then was to increase or overboost the engine which is a result in a higher pressure. You could close the waste gate or tie it shut etc... also opening up the exhaust would allow the turbo to spin faster and make more boost.

Overboost is now a term in modern production cars where the computer allows extra boost for a specific parameter of time. Its usually at low RPMs to get the car to have more torque and makes the car feel like it has linear power. They over produce boost at lower levels because it is isn't maxing out the engines capabilities such as fuel delivery or even stress levels on the engine itself. What I mean by that is if an engine normally runs 20 psi at 7k rpm and make 500hp these new overboost modes will allow the engine to run 25psi at 4k rpm to make 400hp but just for a short time and it bleeds off the extra boost. Some cars allow the 25psi all the way to redline but it will only be available in limited quantities and under ideal conditions (not too hot, engine not too hot, oil temp ideal etc...)

So... what has happened to the poster is... he freed up some backpressure allowing the turbos to spin faster... which is creating extra boost. Now the computer is trying to say hey... we may have a problem... im trying not to allow for this extra boost and I can't stop it... something is wrong... maybe a wastegate failure etc...

 

Keep us posted.