The Broken Fiat Club

MadFiat wrote: ↑Thu Nov 01, 2018 10:35 am What gear did you do your runs in?

Dyno runs were completed in 4th gear, the car topped out at about 180kph. I have some videos, they don’t do the car justice because it is loud on the dyno !! Hearing the sound and smelling race gas, made me proud of the little guy .

MadFiat wrote: ↑Thu Nov 01, 2018 7:22 pm Hate to bring up this can of worms....

Because I know how some on this thread stand, and I'm not trying to cast doubt on anyone's data ....

but ....

2wd dyno cutting power up top... it is a thing. Hard to compare tunes in the high RPM if they're not done on properly linked 4wd dyno... Knowing Greg, and having seen their test video, and my experience with this platform. I do believe that's a thing.

I still haven’t seen any evidence other than the cars limiters flicking the throttle body; which happens on and off the dyno. I went as far as measuring the temperature of the rotors, to which they didn’t increased. The big three (AFR, timing, boost) were identical as they were on road within some shift here and there for different loads. The car traps 94-95MPH which is on par for 175-185whp and 2700 pounds.

Anyway, we can totally have another thread on that. I’ve been pretty scientific about it and I haven’t been able to explain how less power can be achieved without limiting air, fuel, spark. That’s when I took a high resolution log of the throttle body and observed that it was snapping closed, never completely but I did observe spikes around 75%!
M

operamatt wrote: ↑Thu Nov 01, 2018 6:02 pm this has me thinking a bit on what tune to choose. i really want the bangs & the most reliable tune for heavy track use. sold my rrm stage 2.5 a month ago and i need to make a decision soon since i currently have no tune. The low end torque from the Phase 2 is a benefit coming out of low speed corners and i would rather run rich at high rpms on a track, but i have not decided yet.

You can always buy my used handheld to save some money . P&B would not be the most reliable option for hard core track driving btw, no matter who you get it from.

That type of tune is causing explosions in the exhaust, that will increase back pressure on the turbo while not normally a bad thing, it is causing pulses with sharp and sudden shifts in the pressure that causes a shock.

Now if you’re like me and want to hoon while also racing autocross or lapping have at it! Just know that it is technically not as reliable as without the pops and bangs.

doverosx wrote: ↑Thu Nov 01, 2018 10:30 pm

operamatt wrote: ↑Thu Nov 01, 2018 6:02 pm this has me thinking a bit on what tune to choose. i really want the bangs & the most reliable tune for heavy track use. sold my rrm stage 2.5 a month ago and i need to make a decision soon since i currently have no tune. The low end torque from the Phase 2 is a benefit coming out of low speed corners and i would rather run rich at high rpms on a track, but i have not decided yet.

You can always buy my used handheld to save some money . P&B would not be the most reliable option for hard core track driving btw, no matter who you get it from.

That type of tune is causing explosions in the exhaust, that will increase back pressure on the turbo while not normally a bad thing, it is causing pulses with sharp and sudden shifts in the pressure that causes a shock.

Now if you’re like me and want to hoon while also racing autocross or lapping have at it! Just know that it is technically not as reliable as without the pops and bangs.

i’m with you here, in this case i’m willing to sacrifice alittle reliability for the fun of pops and bangs. If it were a race car my decision would be different but this is a fun track car build.

operamatt wrote: ↑Fri Nov 02, 2018 6:03 am

doverosx wrote: ↑Thu Nov 01, 2018 10:30 pm

operamatt wrote: ↑Thu Nov 01, 2018 6:02 pm this has me thinking a bit on what tune to choose. i really want the bangs & the most reliable tune for heavy track use. sold my rrm stage 2.5 a month ago and i need to make a decision soon since i currently have no tune. The low end torque from the Phase 2 is a benefit coming out of low speed corners and i would rather run rich at high rpms on a track, but i have not decided yet.

You can always buy my used handheld to save some money . P&B would not be the most reliable option for hard core track driving btw, no matter who you get it from.

That type of tune is causing explosions in the exhaust, that will increase back pressure on the turbo while not normally a bad thing, it is causing pulses with sharp and sudden shifts in the pressure that causes a shock.

Now if you’re like me and want to hoon while also racing autocross or lapping have at it! Just know that it is technically not as reliable as without the pops and bangs.

i’m with you here, in this case i’m willing to sacrifice alittle reliability for the fun of pops and bangs. If it were a race car my decision would be different but this is a fun track car build.

As fun as Pops & Bangs are, I'm just going to stay away for now.

I am sure MAD FIAT's engine was already mortally wounded prior to P&B tune, because it had been idling rough for a while prior. However, when I flashed the P&B tune, the engine decidedly took a sudden turn for the worse, starting to stall at idle after the very first mile of P&B'ing. Even after flashing back to stock it didn't recover. Not sure how it would have made it worse, but the timing seems highly coincidental.

very interesting :/

i’m getting mixed messages with the effect of pops and bangs. On one hand i heard somewhere that hyundai put pops and bangs in their i30N tune to keep to turbo somewhat spooled when shifting to reduce lag & another camp of enthusiast saying the backpressure slows down the turbo and could cause damage.

operamatt wrote: ↑Fri Nov 02, 2018 10:06 am i’m getting mixed messages with the effect of pops and bangs. On one hand i heard somewhere that hyundai put pops and bangs in their i30N tune to keep to turbo somewhat spooled when shifting to reduce lag & another camp of enthusiast saying the backpressure slows down the turbo and could cause damage.

I think the concern is if the unburnt fuel ignites inside the exhaust runner or inside the turbo, it can create pressure waves where that disrupt the compressor wheel, or create excessive pressure on the back of the exhaust valve. "Anti-lag" systems essentially use these pressure waves to keep the turbine spinning when there's less exhaust flow. However, in racing it has a negative impact on the life of the turbo. I'm sure if Hyundai is using it, they've engineered the exhaust flow in such a way as it isn't igniting the fuel unpredictably, and have likely reinforced various components.

Now, how would pops & bangs affect exhaust valves, such as (maybe) in MAD FIAT's exhaust valve failure? If the fuel ignition occurs behind the exhaust valve, or combustion is still occurring as the exhaust valve opens, it can put forces on the valve in directions it was not designed for, and potentially cause additional wear or damage. The effects would be similar to exhaust detonation.

Now, I'm no expert and that's all theory on my part, pretty much.

that makes sense.

There is two schools of thought to this novelty and motorsport.

Novelty is not by design or purpose other than to burble, snap, and pop by way of retarding timing and dumping fuel off throttle all the time. Side-effects are turbo life decrease, valvetrain life decrease, cylinder washdown that causes pre-mature ring wear/seal failure.

Motorsport is engineered and purposeful. Also there are specific tables, triggers, and conditions to initiate what is known as rolling anti-lag.

Hyundai's strategy is motorsport-esque where there are tables and conditions that need to be met before it activates. Its not on all the time.