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So.... ok, wow. To boost leak or not to boost leak?? That is my question.

I don't think I get what's going on here in one little detail. Capping the venturi...

Does it or does it not cause more maintenance with the canister? With no modification there would be a normal maintenance item with a normal schedule.

If the boost CAN come on three or four-hundred RPM's lower the decision is **** yeah!! The sooner it comes on the better IMO, but only if it isn't a whole other PITA.
 

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I drove around with this mod for two days and had a noticeable dip in fuel economy during city driving, and a definite but small increase in low end torque. In my experience, with this mod, it was much harder to stall the car, and significantly less throttle was needed to get rolling in 1st gear. Turbo lag was lessened, as advertised. It also appeared to reduce the frequency of backfiring while the engine warms up. Still possible, but it was a little bit more difficult and didn't get the impressive burbles and pops that the stock configuration does.
After returning to stock configuration, fuel economy went back up, low end torque went back to normal, and the car was definitely more civilized.
This leads me to believe that the boost leak is an intentional change from the configuration used in the 500 Abarth, in order for the Dart to achieve a higher City MPG rating.

Considering that this mod screws with the normal operation of the engine and can eventually cause a CEL, but definitely improves performance to a degree, it might be a good idea to use a manually or electrically operated valve instead of straight-up plugging the tube. An electric valve could be controlled via a switch in the cockpit. You could go even more complex and only allow the valve to be closed for certain lengths of time so that the operation of the PCV system is only impeded temporarily.
 

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Just so you know, "just to get some HP" is incorrect. You gain absolutely no horsepower by performing this mod, and only get a slightly larger powerband from the turbo (its more responsive at like 3-400 rpms lower).
I believe he was talking about the potential of upgrading from the stock intake to a CAI/SRI setup.... and wondering if any of the aftermarket options block off the tube in question. Pretty sure that after the whole "Just to get some HP" should have been something like "from an intake upgrade".

Jvoid... to answer your question, i've yet to see an aftermarket intake that completely ignores the connection in question here. All the ones i've seen still have the 3 hose connections in one way or another.... be it using factory tubing, or requiring you to remove a piece of the factory tubing to connect other tubes to.
 

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The Tork one has a breather filter, not all connections were used. I think there was a reason... Not sure

The tube is connected to the cold side intercooler piping.
 

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i've been on the fiat500usa forum because i know the owner and the abarth guys are having mixed results. there have been trouble codes but it seems to depend on driving style and may be more frequent with piggyback computers that modify the map or t-map signal.

so i looked into the mod and what's really going on. with a heat gun i removed the T to measure the venturi and ran some calcs. the venturi is 1/16" as i measured with my numbered drill bit set, a #52 it is .0635" and has a slight drag in the hole. the lost airflow is around 2 SCFM at 18psi (that's cfm at a standard density, more or less a mass flow rating) which can account for about 3hp max. i know people like to squeeze every last horsepower but this is something you may decide to leave alone if it throws an evap code.

some claim it effects throttle response and drivability (i don't exactly agree but don't want to get into a pissing match over it) and i would say if you feel it helps by all means do it but if you get a trouble code well, it's not the end of the world reversing it.
 

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PBF is known for being facetious.

To call this a boost "leak" is a tad misleading in my opinion.

It has been dyno'd by DL700 and shown to make no appreciable gains in HP or Torque (within the margin for error on a dyno, close enugh to call it the same).
 

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i'm getting the feeling the "drivability" gains people report are from less fuel vapor in the intake charge. vapor takes up a lot more volume than an atomized liquid, ever drive on a really hot day and the engine doesn't feel crisp with any car? i have big problems with this on my motorcycle when it's hot. it just feels slow but the water temp is normal and sparkplugs read fine.. vapor may burn more readily but the power is less because of less energy density.
 

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doesnt work for me?

I have the ingen aftermarket charge pipes and i run 2 0-60's. one with vacuum hooked up and one with vacuum plugged off and each time i ran around 8s. Maybe this doesn't work for aftermarket charge pipes?
 

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I have the ingen aftermarket charge pipes and i run 2 0-60's. one with vacuum hooked up and one with vacuum plugged off and each time i ran around 8s. Maybe this doesn't work for aftermarket charge pipes?
It doesn't "work" at all. No power is gained or lost from plugging this tiny little tube. There is a dyno around here somewhere in an old tread by DL700 that shows a 1 or 2 HP gain. An that's a difference you would expect to see in two back to back runs anyways (margin o error for the dyno).
 

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It doesn't "work" at all. No power is gained or lost from plugging this tiny little tube. There is a dyno around here somewhere in an old tread by DL700 that shows a 1 or 2 HP gain. An that's a difference you would expect to see in two back to back runs anyways (margin o error for the dyno).
a 3/8" tube is a lot. but the air is restricted downstream in the T which has a hole that's about 1mm. it's a venturi pump and part of the design.
 

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i've been on the fiat500usa forum because i know the owner and the abarth guys are having mixed results. there have been trouble codes but it seems to depend on driving style and may be more frequent with piggyback computers that modify the map or t-map signal.

so i looked into the mod and what's really going on. with a heat gun i removed the T to measure the venturi and ran some calcs. the venturi is 1/16" as i measured with my numbered drill bit set, a #52 it is .0635" and has a slight drag in the hole. the lost airflow is around 2 SCFM at 18psi (that's cfm at a standard density, more or less a mass flow rating) which can account for about 3hp max. i know people like to squeeze every last horsepower but this is something you may decide to leave alone if it throws an evap code.

some claim it effects throttle response and drivability (i don't exactly agree but don't want to get into a pissing match over it) and i would say if you feel it helps by all means do it but if you get a trouble code well, it's not the end of the world reversing it.
I have made this mod by simply adding a Boomba Racing 10mm check valve instead of blocking off the tube. Before ordering the check valve I read everything I could find on this including the Fiat500 forum. I blocked off the hose temporarily and felt improved drivability. Installed the check valve with a small 3/8" hose between the charge pipe and the check valve with all factory hoses left intacked and it still fits up under the engine cover without any modification other than slipping the hose between the cover and the insulation. I love the feel of the boost, in second gear especially. MPG has not changed that I can determine.

My only problem is that my MPG goes down considerably while I am watching my boost gauge!!!!!!!!!!!

I have also adjusted my wastegate to 5mm. That really improved drivability between first and second gear. When I first got my car I was either forced to almost stop to start from 1st because I didn't have enough power to use second gear from a near stop. Now I am happy.

My OBD II gauge shows max boost at 21 on analog. I know it isn't as good as a manual boost gauge, but I can tell you that this mod did not change my level of boost that I could tell from the gauge, but my butt says differently!
 

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I have made this mod by simply adding a Boomba Racing 10mm check valve instead of blocking off the tube. Before ordering the check valve I read everything I could find on this including the Fiat500 forum. I blocked off the hose temporarily and felt improved drivability. Installed the check valve with a small 3/8" hose between the charge pipe and the check valve with all factory hoses left intacked and it still fits up under the engine cover without any modification other than slipping the hose between the cover and the insulation. I love the feel of the boost, in second gear especially. MPG has not changed that I can determine.

My only problem is that my MPG goes down considerably while I am watching my boost gauge!!!!!!!!!!!

I have also adjusted my wastegate to 5mm. That really improved drivability between first and second gear. When I first got my car I was either forced to almost stop to start from 1st because I didn't have enough power to use second gear from a near stop. Now I am happy.

My OBD II gauge shows max boost at 21 on analog. I know it isn't as good as a manual boost gauge, but I can tell you that this mod did not change my level of boost that I could tell from the gauge, but my butt says differently!
Ran this 2 days and 200 miles with the Boomba check valve and threw the code with cruise on at 70 mph. Guess I will go back down slightly in power to save my canister!
 

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Ran this 2 days and 200 miles with the Boomba check valve and threw the code with cruise on at 70 mph. Guess I will go back down slightly in power to save my canister!
What code did it throw??? DO you remeber?
 

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When engineered this was not supposed to affect anything.
This can be identified by the placement of the MAP sensor which is located behind the air tube.
Thus the ECU accounts for the difference in air pressure between the Wastegate Control Solenoid (Boost Control Solenoid) and the MAP sensor.

The obvious problem with this is loss of air flow from the turbo, and a non precise metering of air from the turbo to the MAP sensor since there is loss just prior to the MAP sensor which can vary depending on temperature and altitude.

This system can be improved upon in two, possibly three ways:

1. Remove the parameters in the ECU calculate for this air flow loss, and plug the hole.

2. Create a greater separation between the MAP sensor and the hole for increased precision of air pressure monitoring.

3. Possible** plug the hole and replace with a filter element on that end of the hose, maintaining the intake side connected.
This is because that purge line closes at the manifold under boost.
 
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