3.5 vs. 5.0 exhaust volume
#1
Just wondering if because the Eco uses pressurized combustion air, would the spent exhaust gases equal, be higher or lower than the amount expelled by the 5.0L motor?
Stupid question?
I'd think it would be obvious with N/A motors but the turbo charging throws me off. Does compression ratio have anything to do with this?
Edit: my Eco has quite a bit of exhaust after initial startup (condensation) and its just idling. (Air temp. Is near 0C or 32F outside
Stupid question?
I'd think it would be obvious with N/A motors but the turbo charging throws me off. Does compression ratio have anything to do with this?
Edit: my Eco has quite a bit of exhaust after initial startup (condensation) and its just idling. (Air temp. Is near 0C or 32F outside
Last edited by elkymutt; 03-11-2013 at 04:42 PM.
#4
Senior Member
I can say that the turbos act as a restriction and just from a sound you hear by ear stand point every turbo motor seems quieter then a non turbo motor of the same overall design.. I think with all things being equal a turbo motor would be quieter
Also: like mike said your question about the condensation I really have NO clue what you are trying to ask.. May want to re-phrase it
Also: like mike said your question about the condensation I really have NO clue what you are trying to ask.. May want to re-phrase it
#5
Senior Member
You keep garbage off the forum
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engineermike (03-11-2013)
#6
Sorry, I meant volume of gases not volume in decibels.
I only brought up the condensation because when I startup from cold, the exhaust gases are really spewing out the exhaust (the white condensation gases are the easiest way to see this)
Although quite different motors, my old '03 3.8L GM had only a slow exit of the exhaust gases after start up.
And considering the exhaust systems are the same for both the 3.5 and 5.0 motors...
I only brought up the condensation because when I startup from cold, the exhaust gases are really spewing out the exhaust (the white condensation gases are the easiest way to see this)
Although quite different motors, my old '03 3.8L GM had only a slow exit of the exhaust gases after start up.
And considering the exhaust systems are the same for both the 3.5 and 5.0 motors...
Last edited by elkymutt; 03-11-2013 at 09:57 PM.
#7
Senior Member
Ok, so it's like this. . . at WOT, 360 vs 365 hp will generate nearly the same amount of exhaust gas. What happens between the air filter and tail pipe doesn't make much difference as long as the BSFC is similar.
At idle, 3.5 liters will use less fuel and, therefore, generate less exhaust gas than 5 liters.
HOWEVER. . . in recent years there has been a big push to get the cats to "light off" quicker. You do this by sending more heat to them. On the 5.0, this might mean retarding the ignition timing. If you've ever installed a distributor one tooth retarded and saw your headers glowing red at idle, you know what I mean. I'm fairly certain they do this on both the 3.5 and 5.0. However, with the GDI 3.5 they MAY be doing some funny business with injectors pulsing at odd times to get more heat into the cats even faster. If this is the case, it's possible the 3.5 generates more exhaust gas on cold-start for the first 5-10 seconds.
I know for sure that the turbos spool up significantly on cold-start with the BPV's open. The only thing that could cause this at idle is excess heat in the exhaust gas, explained by the above. I've also logged ignition timing and it starts out way retarded (like, ATDC) then within 10 seconds returns to more conventional values. Not-so-coincidentally, the turbos slow and quiet as the timing ramps up.
At idle, 3.5 liters will use less fuel and, therefore, generate less exhaust gas than 5 liters.
HOWEVER. . . in recent years there has been a big push to get the cats to "light off" quicker. You do this by sending more heat to them. On the 5.0, this might mean retarding the ignition timing. If you've ever installed a distributor one tooth retarded and saw your headers glowing red at idle, you know what I mean. I'm fairly certain they do this on both the 3.5 and 5.0. However, with the GDI 3.5 they MAY be doing some funny business with injectors pulsing at odd times to get more heat into the cats even faster. If this is the case, it's possible the 3.5 generates more exhaust gas on cold-start for the first 5-10 seconds.
I know for sure that the turbos spool up significantly on cold-start with the BPV's open. The only thing that could cause this at idle is excess heat in the exhaust gas, explained by the above. I've also logged ignition timing and it starts out way retarded (like, ATDC) then within 10 seconds returns to more conventional values. Not-so-coincidentally, the turbos slow and quiet as the timing ramps up.
Last edited by engineermike; 03-11-2013 at 11:06 PM.
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#8
Senior Member
Ok, so it's like this. . . at WOT, 360 vs 365 hp will generate nearly the same amount of exhaust gas. What happens between the air filter and tail pipe doesn't make much difference as long as the BSFC is similar.
At idle, 3.5 liters will use less fuel and, therefore, generate less exhaust gas than 5 liters.
HOWEVER. . . in recent years there has been a big push to get the cats to "light off" quicker. You do this by sending more heat to them. On the 5.0, this might mean retarding the ignition timing. If you've ever installed a distributor one tooth retarded and saw your headers glowing red at idle, you know what I mean. I'm fairly certain they do this on both the 3.5 and 5.0. However, with the GDI 3.5 they MAY be doing some funny business with injectors pulsing at odd times to get more heat into the cats even faster. If this is the case, it's possible the 3.5 generates more exhaust gas on cold-start for the first 5-10 seconds.
I know for sure that the turbos spool up significantly on cold-start with the BPV's open. The only thing that could cause this at idle is excess heat in the exhaust gas, explained by the above. I've also logged ignition timing and it starts out way retarded (like, ATDC) then within 10 seconds returns to more conventional values. Not-so-coincidentally, the turbos slow and quiet as the timing ramps up.
At idle, 3.5 liters will use less fuel and, therefore, generate less exhaust gas than 5 liters.
HOWEVER. . . in recent years there has been a big push to get the cats to "light off" quicker. You do this by sending more heat to them. On the 5.0, this might mean retarding the ignition timing. If you've ever installed a distributor one tooth retarded and saw your headers glowing red at idle, you know what I mean. I'm fairly certain they do this on both the 3.5 and 5.0. However, with the GDI 3.5 they MAY be doing some funny business with injectors pulsing at odd times to get more heat into the cats even faster. If this is the case, it's possible the 3.5 generates more exhaust gas on cold-start for the first 5-10 seconds.
I know for sure that the turbos spool up significantly on cold-start with the BPV's open. The only thing that could cause this at idle is excess heat in the exhaust gas, explained by the above. I've also logged ignition timing and it starts out way retarded (like, ATDC) then within 10 seconds returns to more conventional values. Not-so-coincidentally, the turbos slow and quiet as the timing ramps up.
#9
Well for one a forced induction motor uses more fuel than a conventional motor at WOT to aid In detonation prevention and a cold motor also uses more fuel like a carburetor choke effect
#10
Senior Member
Every now and then a tuner may try to richen a FI motor up some to suppress detonation, but it's not something that the OEM's can/will necessarily do.