PPE V8 Headers GS, LS, SC
01-04-11, 12:37 PM
#151
i didnt notice much a little rumble but not much else till i got my exhuast leak fixed
then the butt dyno showed some improvement....i wasnt looking for alot thoughwhen you say "IT may cause some low response"are you thinking i should pick up some low end then?
Last edited by sakataj; 01-04-11 at 12:42 PM.
01-04-11, 01:35 PM
#152
Lexus Champion
that is the exact Y pipe i have john BUT, it is not stock... i dunno if it will matter but it came with the greddy exhaust and when it did i installed the greddy Y-pipe. the greddy evo II is a 3 piece exhaust 2 canisters which bolt up after the axle and the new y-pipe which bolts up at the b pipe i think its called
i didnt notice much a little rumble but not much else till i got my exhuast leak fixed then the butt dyno showed some improvement....i wasnt looking for alot though
when you say "IT may cause some low response"are you thinking i should pick up some low end then?
i didnt notice much a little rumble but not much else till i got my exhuast leak fixed
then the butt dyno showed some improvement....i wasnt looking for alot thoughwhen you say "IT may cause some low response"are you thinking i should pick up some low end then?
What is important to understand is that for MOST of the RPM range of the engine the stock exhaust is BIGGER than necessary for the VOLUME of flow.
PEAK flow is 300hp that requires flowing 300hp of exhaust volume. This is at +-6000rpm. Peak torque of 310tq occurs at 4000rpm and that equals 236hp. So, at 4000rpm the exhaust is flowing about 80% of its flow at 6000rpm. At 3000rpm it is only flowing 166hp or 55% of the exhaust capacity. At 2000rpm it is about 30%.
This flow is NEVER smooth. It is non-stop pulsing with every exhaust cycle of the 8 cylinders. Each pulse creates a pressure wave away from the engine in the exhaust system which is followed by a pressure rebound wave back towards the engine when each pulse ends.
What is wanted is a system that allows EACH pressure pulse to move easily away from the engine while limiting the rebound pressure wave back towards the engine. Small pipes, velocity, catalysts, collectors and more tend to do this. Larger tubes and removing parts lowers velocity and makes it EASIER for the rebound pressure waves to return to the engine. This reduces power and response. Of course too small or restrictive of a system will limit peak flow and hurt peak power.
The factory Y pipe has a specialized design that allows peak flow but restricts reverse flow.
01-04-11, 01:50 PM
#153
The Greddy "Y-pipe" shown is not the FIRST Y-pipe. The first Y-pipe is the critical one from the catalysts to the single center pipe. After that point you could use a single exhaust or use another Y pipe (such as the Greddy or the stock one) to split it back into duals. Again, it is the FIRST Y-pipe that I have been discussing and is what I am referring to when I say STOCK Y-pipe.
01-04-11, 01:54 PM
#154
^100% agreed. oem-sized exhaust components are plenty adequate for a car with even mild to moderate engine mods. It's not until you are really pushing more CFM into the engine (i.e. turbo or supercharger) where then it REQUIRES larger exhaust components to properly expel the exhaust due to the higher output of power.
01-04-11, 02:26 PM
#155
Rookie
iTrader: (10)
Join Date: Jun 2010
Location: fl
Posts: 69
Likes: 0
Received 0 Likes
on
0 Posts
The way Im starting to look at things is like this how much time do you spend down low vs mid n upper rpm range after launch might be a worthy sacrifice if there is more mid to upper just my opinion.
01-04-11, 02:39 PM
#157
Rookie
iTrader: (10)
Join Date: Jun 2010
Location: fl
Posts: 69
Likes: 0
Received 0 Likes
on
0 Posts
It's alot better today at a light the rpm bounce on me again but this has nothing to do with the install It happenend before once or twice only after tm plugs I'm going bck to ngk still not what I expected but maybe because I'm not stock I think if I can accomplish a tune it will make up what I'm looking for .
01-05-11, 05:56 AM
#158
It's alot better today at a light the rpm bounce on me again but this has nothing to do with the install It happenend before once or twice only after tm plugs I'm going bck to ngk still not what I expected but maybe because I'm not stock I think if I can accomplish a tune it will make up what I'm looking for .
01-05-11, 01:11 PM
#160
Lexus Champion
It's alot better today at a light the rpm bounce on me again but this has nothing to do with the install It happenend before once or twice only after tm plugs I'm going bck to ngk still not what I expected but maybe because I'm not stock I think if I can accomplish a tune it will make up what I'm looking for .
01-05-11, 10:11 PM
#165
Rookie
iTrader: (10)
Join Date: Jun 2010
Location: fl
Posts: 69
Likes: 0
Received 0 Likes
on
0 Posts
Well my dyno is off until i figure this out got my first engine check light on the car 
here are all the codes (p0441 evaporative emission control system incorrect flow detected) (po446(pd) evaporative emission control system vent) control circuit po455(pd) po455 evaporative emission control system leak detected large leak and p2418(pd) undefined code.
here are all the codes (p0441 evaporative emission control system incorrect flow detected) (po446(pd) evaporative emission control system vent) control circuit po455(pd) po455 evaporative emission control system leak detected large leak and p2418(pd) undefined code.