You can reach 545WHP on stock cats, upgraded intakes and an e85 tune from Ideal.

Cats on the QVs are not a restrictive point—rip the complete stock exhaust off to the wastegates and dyno—about 8WHP.

Downpipes, HFCs, new exhausts, etc. are just very expensive sound amplifiers for QVs.

After you stack downpipes and the rest of the exhaust back on, you’ll maybe see 2WHP.

 

Like 614 said, downpipes are useless - not just on the QV, but also on the 2.0.

On many cars, the cats and exhaust is restrictive, whether as a cost saving measure, or to meet emissions/noise requirements, etc. The Giulia on the other hand is very well designed and highly optimized from the factory, such that the limiting part of the car is not the exhaust or intake, but the turbo itself. True, you are limited in terms of what you can do with the aftermarket, but this also means that the Giulia is a fantastic car bone-stock.

Power-wise though the only way to make significant power gains, beyond throwing a JB4 on (2.0) or getting a flash tune (QV), is to go hybrid turbo. Anything else is purely for noise or clout, even Remus claims only a 2 hp bump with their race exhaust setup - which is essentially a rounding error! Sadly our engines are not very tunable, but they are still quite full of character.

Nobody is stopping you from downpiping your car, of course, but IMO you're better off spending that money on a tune or wheels and tires, if you want more performance.

 

Imo a hfc is better sounding than any of the after market exhaust and cheaper. As far as gains you may see 10-15whp on a 200cel vs stock 700cel. And to me 10-15whp adds up. Go hybrid turbo, catless and e85 you see bigger gains

 

Why is it that downpipes for these cars aren’t a mayor deal ?

QV has sport cats from stock. Max backpressure is 5psi at 32 psi of boost at 4200RPM and up to 7500RPM.
100-200km/h 0.1sec faster
Just don't waste your money. Same for the intake. If you want to get high IAT - install "sport" intake.

Same for e85 I see that ( ideal tuning ) is working on something for e85
But I don’t see anything else on it is there any other information on this ?

I tuned my car and the result is 0.8sec faster on E85.
7.4sec vs 6.5-6.6sec 100-200km/h.
The mixture is around 25% richer and the ignition angle is way advanced. The stock fuel system is barely enough, but still enough. Cold start is just a little longer. I believe you can get low 6 (100-200km) and low 7 (60-130mph) because my car equipped with MT and I live in mountains 720m. But without assembler patch your car will be jerky(if you want more than 540hp) and this patch is not one byte like a stupid start stop inversion patch. 540hp is nothing for Stage 1, most tuners just don't understand how to tune 2.9T and that's why BMW owners think that Alfa QV is crap.

 

Imo a hfc is better sounding than any of the after market exhaust and cheaper. As far as gains you may see 10-15whp on a 200cel vs stock 700cel. And to me 10-15whp adds up. Go hybrid turbo, catless and e85 you see bigger gains

Is that 10-15 with a tune or just the hfc alone

 

I’m not following the logic on hfc’s adding any horsepower. QV, dyno, stock exhaust, 433WHP. Same QV, dyno, complete removal of everything, exhaust blowing straight into the ground, 441WHP. Anything added only takes away from that 8WHP.

 

No DP and exhaust creates a worse environment for the flow of gasses. If you'd add a divergent/convergent cone to help guide the gasses you'd see more boost in power.

 

I’m not following the logic on hfc’s adding any horsepower. QV, dyno, stock exhaust, 433WHP. Same QV, dyno, complete removal of everything, exhaust blowing straight into the ground, 441WHP. Anything added only takes away from that 8WHP.

I asked bc I remember seeing somewhere on the company's website that one of their hfc for, albeit, a different car, made an extra 20-30 hp; so I was wondering if that was the case with the qv. I can't remember though if the description said that was with a tune, vs. without (i.e. tune adds 50hp and hfc plus tune adds extra 20-30 on top of that, or if no tune was needed to get the extra 20-30 with hfc)