new to site
new to site
whats up everyone. im new to this site but not new to forums. i own two nissans and will have a third on monday. i have an 88 4cyl pickup a 91 v6 pickup and am getting a 92 240sx monday. i also own a 95 pontiac trans am. i am getting the 240 for my sister. it is hit in the front and in the back but i can do all the work myself. i am here to put my two cents worth in and get as much info as can possibly be found about this car. i am gonna do some mods to it so she can have a little bit of fun and play with me when im in my TA. i wanted to start off knowing what seems to be the best first mod i know with my car it was the intake. the original intake for the TA only flows enough air for a 305 at 3200 rpm, my car being a 350 thats spins to 6200rpm needed more air. alot of you talk about exhaust being a big impovement. i have a high flow cat and a flowmaster on my v6 truck, it makes it sound like a mustang. on my 4 banger i have the same setup but it sounds like a rumbly honda. i was told thier isn't enough air comming out of the engine to fill up the flowmaster and make it resonate corrcetly so is thier a similar problem with the 240. and has anyone put a dual exhaust setup on thier car. i think if i leave the cat alone and keep with small pipes i won't loose back pressure but will open up the motor. o well i better shut up i'll be back here tomorrow sorry about the long post.
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UnderPressure
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- Joined: Mon Sep 23, 2002 10:10 am
back pressure is actually a bad thing, i think this is what K car is saying. You want velocity, not backpressure. With velocity, itpreduces a small vacuum, or scavenging effect, sucking out spent gasses from the combustion chamber. This way it fills up with more clean fresh air, and fuel. If you want ever more air, get a TURBO.
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UnderPressure
- Posts: 459
- Joined: Mon Sep 23, 2002 10:10 am
Re: Re: new to site
Lost_To_A_K-Car wrote:Originally posted by cndctrdj "]has anyone put a dual exhaust setup on thier car. i think if i leave the cat alone and keep with small pipes i won't loose back pressure but will open up the motor.
1. Engines don't need backpressure. That's a myth.2. Dual exhausts are pointless on an inline four cylinder engine.
1. with a high 2 flow cats on my friends corvette he lost the ability to chirp second2. it would look sweet on that car thats all iknow its pointless. on that not isn't it pointless to "try" and make a honda fast !!!
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Unregistered
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- Joined: Wed Sep 11, 2002 8:52 am
- Car: I enjoy Cars, girls, TV, hanging out with friends, hanging out at car shows, listening to System of
Okay, I might be crazy here, but isn't a too big exhaust system a bad thing, like a 3 in. exhaust on a non-turbo engine? The way it was explained to me was like this. Exhaust comes out in small bursts, pulses if you will. Different types of engines give out different sizes of pulses..ex. V-8 and tt V-6 will give out a large pulse, V-6 and turbo four will give out med. pulse, NA 4 cyl gives out a small pulse. Now you don't want the diameter of the exhaust to be bigger than the diameter of the pulse. Why is that bad? Because the pulses tend to bounce back and forth inside the exhaust system, not exiting it quickly. Now in high reving engines, commomly found in imports, the cam lobes are positioned so that the exhaust valves can be open at the same time the intake valves are(called valve overlap). Now under normal situations the pulses cause a vacuum that sucks the exhaust out of the combustion chamber. But when someone puts an excessively large exhaust system (or a dual exhaust on an inline 4), and the the pulses start to bounce back and forth that vacuum is greatly reduced or even absent. When that happens, and the valve overlap occurs(remember at high rpms), the exhaust pulses can back up and can actually be pulled back in to the combustion chamber, and be burned again, causing a loss of power, and damage to the engine....Sorry if that was kinda long, but am I wrong on that?