[Fiatbreath]

If I do not tune my 124, how much HP can I expect from a complete quad exhaust and v1 or v4 intake?. Thanks in advance

 

[MotoPete]

You don't need to tune it. The ECU can adjust to changes in air flow.

As to how much additional power you'll make, a handful of ponies I suppose, nothing spectacular for the cost outlay if that is a factor.

Folks generally do these things for the bling factor and sound.

 

[JFernald]

If I do not tune my 124, how much HP can I expect from a complete quad exhaust and v1 or v4 intake?. Thanks in advance

Since the two in combination would not just be the total of the two individual add-ons, someone would have to dyno that exact combination to give you a definitive answer. Taking the vendors claims and adding them together may understate or overstate the hp gain. For example 10 hp each may add up to 24 or 16, rather than 20.

 

[JFernald]

You don't need to tune it. The ECU can adjust to changes in air flow.

As to how much additional power you'll make, a handful of ponies I suppose, nothing spectacular for the cost outlay if that is a factor.

Folks generally do these things for the bling factor and sound.

Pete believe's he is now psychic. He can attribute motive to people he has never even seen. Performance improvement must be a significant factor or measuring those gains would be a waste of money by the vendors.

 

[Good-Win Racing]

Full Quad System on dyno below. No tune, that's just bolt on exhaust system (stock intake, etc).

Turbo spools a lot earlier, the big gains are in TORQUE at the low end. Torque is what you actually feel pushing you back in the seat. Lowest Line is Best STOCK Pull. Middle Line is Best Pull with just highflow Muffler Upgrade. Highest Line is Best Pull Full Crosspipe, Midpipe, Muffler...Peak HP up 'only' about 15hp but notice total area under the torque curve is massively better, up over 30 Ft/lbs of torque through much of the middle rpm range, peak gains over 50 Ft/lbs at the low end thanks to faster spool for the turbo.

And the sound gets a ton of compliments...

 

[MotoPete]

15 hp for the Fiat's dynoed 146 hp is ~10%, which is congruent with the oft quoted figures of companies like Magnaflow...

http://www.magnaflow.eu/07techtips/faq/question22.asp

As Brian has pointed out overall there is a roughly ~18% increase in torque (aside from the anomaly at 2650 rpm), but it's not the question the OP asked. (though maybe what he meant perhaps?)

The outright dollar per hp ratio for both a freer flowing intake (the improvements from these are highly debatable) and exhaust (firmly established, and Brian's effort for the 124 sounds fantastic!) aren't nearly as good as say a tuning option.

John, I accounted for people like yourself who are delusional by putting "generally" in italics.