different kind of exhaust modification
01-08-2009, 10:38 PM
#26
After having a look at the OP's setup, I thought this might be an interesting addition if someone was using Racing Beat's single-sided track exhaust. Specifically, the single-sided Racing Beat exhaust would be the muffled side, leaving a perfect location for a straight pipe to exit from the cut-out (where the other exhaust tip would normally be). Whether such a set-up would offer any advantage, I don't know; but I thought it was an interesting idea, so I thought I'd throw it out there. Even if it fails, maybe it gives someone else an idea he or she can use.
01-08-2009, 11:23 PM
#28
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what do you mean turn the valve down? the valve is either completely opened or completely closed. it's an one touch system with the timing pre calculated so that i don't have to second guess how much the valve is closed or opened.
01-08-2009, 11:42 PM
#29
all you guys...
how often are you guys on ls1tech or speak with people that own or are knowledgeable about modifying v8s? if you want information on cutouts, thats the first place to start. there is too much misinformation here.
cutouts do gain hp. but do you know the downside? a comparable loss of torque. thats why its ok on a ls1, they have tons of torque and what they need is top speed. (for drag racing.)
do you know what the rx8 lacks? torque.
cutouts on the rx8 are a pretty stupid idea.
how often are you guys on ls1tech or speak with people that own or are knowledgeable about modifying v8s? if you want information on cutouts, thats the first place to start. there is too much misinformation here.
cutouts do gain hp. but do you know the downside? a comparable loss of torque. thats why its ok on a ls1, they have tons of torque and what they need is top speed. (for drag racing.)
do you know what the rx8 lacks? torque.
cutouts on the rx8 are a pretty stupid idea.
01-09-2009, 12:49 PM
#30
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^the question isn't about peak torque and peak horsepower, it's about area gained or lost under the usable area of the torque curve. Also, the renesis is a far cry from an LS1, so don't make the assumption that they will behave in the same manner.
01-09-2009, 01:18 PM
#31
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all you guys...
how often are you guys on ls1tech or speak with people that own or are knowledgeable about modifying v8s? if you want information on cutouts, thats the first place to start. there is too much misinformation here.
cutouts do gain hp. but do you know the downside? a comparable loss of torque. thats why its ok on a ls1, they have tons of torque and what they need is top speed. (for drag racing.)
do you know what the rx8 lacks? torque.
cutouts on the rx8 are a pretty stupid idea.
how often are you guys on ls1tech or speak with people that own or are knowledgeable about modifying v8s? if you want information on cutouts, thats the first place to start. there is too much misinformation here.
cutouts do gain hp. but do you know the downside? a comparable loss of torque. thats why its ok on a ls1, they have tons of torque and what they need is top speed. (for drag racing.)
do you know what the rx8 lacks? torque.
cutouts on the rx8 are a pretty stupid idea.
Second, an LSX engine from the factory is choked pretty bad by the factory intake and exhaust systems. When I helped my friend Jim with his Z28, I couldn't believe how much power there was to be unlocked. The Renesis doesn't suffer from this. Even older rotaries stood massive power gains from simple intake and exhaust mods. Not the Renesis. A few is all you'll get.
Third, you can not gain horsepower but lose torque. It doesn't work that way. If you gain one you gain the other. They are mathematically related and whatever you do to one, you do to the other. Torque does no work and is irrelevant to know when it comes to performance anyways. The ONLY time anyone anywhere needs to know anything about torque is when designing engines or drivetrains. That's it. Torque is the force that is trying to twist everything apart. Horsepower is what moves you and the only thing relevant to performance.
I'm sure you mean to say is gain high end horsepower at the expense of low end horsepower (which is always incorrectly referred to as torque). This has nothing to do with exhaust restriction or backpressure and everything to do with exhaust velocity. Keep in mind that a loss in low end power with a gain in top end power is actually nothing more than a shift of the powerband upwards in the rpm range. As you move a powerband up you also narrow it's usable range. If you shift a powerband downward, you widen it's usable range. There is no gain or loss. It's only where you centered it at. Thes rest takes care of itself.
01-09-2009, 01:20 PM
#32
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One of the mods we did on my friend Jim's car from my above post was to install a q-teq electronic cutout which is almost identical to what the OP has shown. It worked great on that car (Z-28). I bought one and installed it on my RX-7. To make a long story short, it was on that car a total of 1 whole day and has been on my fiancee's dad's car for the past 3 years.
Keep them off of rotaries. It's a waste of time and hearing!
Keep them off of rotaries. It's a waste of time and hearing!
01-09-2009, 01:20 PM
#33
Is this title ok?
Just make sure you re-route/extend it if you ever bring your car to the track. If the plastic bumper can melt from a free flowing exhaust (how did I know?), I'm sure you don't want to take that risk.
01-09-2009, 01:34 PM
#35
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One of the mods we did on my friend Jim's car from my above post was to install a q-teq electronic cutout which is almost identical to what the OP has shown. It worked great on that car (Z-28). I bought one and installed it on my RX-7. To make a long story short, it was on that car a total of 1 whole day and has been on my fiancee's dad's car for the past 3 years.
Keep them off of rotaries. It's a waste of time and hearing!
Keep them off of rotaries. It's a waste of time and hearing!
i don't know why everyone is against an uncorked renesis. has anyone tried it?
01-09-2009, 01:55 PM
#36
Is this title ok?
That look nice and definitely will help. It still be too short for my taste to be comfortable as the flame still be shooting under the car as it create lot of heat from open flame; those plastic and rubbers will endure lots of heat. For street use maybe. I have the same idea a few year ago by cutting a hole in the exhaust and open it up at the track, but scratched that idea as fast as I could after knowing how hot the rotary exhaust were. It's fun to try different thing, but safety should not be over looked.
01-09-2009, 02:41 PM
#37
Zoom Zoom....
Trustbuddy.
That downturn pipe should help a little. It should also protect the valve butterfly.
I still am not a fan of exhaust exiting under the car. Not only for all of the fire/melting hazards, but also the risk of CO poisoning. Note all of the soot in your pictures.
A Nascar-type flattened pipe exiting just forward of the passenger rear wheel should be fairly unobtrusive (compared to the un-muffled noise, that is).
Some others have mentioned having a cutout for the track. As far as racetracks go, everywhere (almost) I've been has had Very Strict noise limits that are enforced with sound meters - especially on test days. From the racetrack operator's point of view, it's bad for the neighbours. Sanctioning bodies also have DB limits so they get invited back to the tracks...
That downturn pipe should help a little. It should also protect the valve butterfly.
I still am not a fan of exhaust exiting under the car. Not only for all of the fire/melting hazards, but also the risk of CO poisoning. Note all of the soot in your pictures.
A Nascar-type flattened pipe exiting just forward of the passenger rear wheel should be fairly unobtrusive (compared to the un-muffled noise, that is).
Some others have mentioned having a cutout for the track. As far as racetracks go, everywhere (almost) I've been has had Very Strict noise limits that are enforced with sound meters - especially on test days. From the racetrack operator's point of view, it's bad for the neighbours. Sanctioning bodies also have DB limits so they get invited back to the tracks...
01-09-2009, 03:10 PM
#38
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Third, you can not gain horsepower but lose torque. It doesn't work that way. If you gain one you gain the other. They are mathematically related and whatever you do to one, you do to the other. Torque does no work and is irrelevant to know when it comes to performance anyways. The ONLY time anyone anywhere needs to know anything about torque is when designing engines or drivetrains. That's it. Torque is the force that is trying to twist everything apart. Horsepower is what moves you and the only thing relevant to performance.
It is easier (in my mind) to talk about torque, because a gain of 5 ft lbs is the same no matter where it appears in the engine's RPM range, but a gain of 5 horsepower means different things in relation to acceleration depending on what RPM it occurs at.
In the end, they're totally equivalent as one can be derived from the other (assuming RPM is known as well), so it's your preference as to which you prefer to think about. To say either one is irrelevant is incorrect.
01-09-2009, 03:53 PM
#39
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Torque doesn't move you as torque does no work. None at all! You can have torque and have no work. You can not move a car and not be working. Horsepower can not exist without movement and hence work this is because horespower is a measure of work. Torque isn't. Since you need to do work to move a vehicle you can only measure it in horsepower. Torque can not move a car. Once you set torque in motion, time and distance is added to the equation and the output of that equation with the new variables is a new number. We have given it a name. Horsepower!
5ft lbs being the same across the rpm spectrum whereas horsepower isn't is primarily why you don't want to use torque in conversation and why it's completely irrelevant. It tells you nothing! If someone tells you their engine makes 200 ft lbs of torque, it doesn't tell you how fast it potentially is. 200 ft lbs where? 1000 rpm or 8000 rpm? If they say 1000 rpm that means they have 38 hp. If they say 8000 rpm, they have 305 hp. BIG difference!
If someone says my car makes 200 hp, you don't really care about knowing torque. You know that if they can make 200 hp at 1000 rpm then holy smokes they've got some power down low! If they make 200 hp at 8000 rpm then we've still got a good idea of how quick they are as it's basically what the RX-8 does at the wheels. FWIW 200 hp at 1000 rpm is 1050 ft lbs and 200 hp at 8000 rpm is 131 ft lbs. Torque doesn't tell you crap!
Anyone can argue about this all they want I really don't care. I didn't make this stuff up. However if they don't agree with this, THEY ARE WRONG!!!
5ft lbs being the same across the rpm spectrum whereas horsepower isn't is primarily why you don't want to use torque in conversation and why it's completely irrelevant. It tells you nothing! If someone tells you their engine makes 200 ft lbs of torque, it doesn't tell you how fast it potentially is. 200 ft lbs where? 1000 rpm or 8000 rpm? If they say 1000 rpm that means they have 38 hp. If they say 8000 rpm, they have 305 hp. BIG difference!
If someone says my car makes 200 hp, you don't really care about knowing torque. You know that if they can make 200 hp at 1000 rpm then holy smokes they've got some power down low! If they make 200 hp at 8000 rpm then we've still got a good idea of how quick they are as it's basically what the RX-8 does at the wheels. FWIW 200 hp at 1000 rpm is 1050 ft lbs and 200 hp at 8000 rpm is 131 ft lbs. Torque doesn't tell you crap!
Anyone can argue about this all they want I really don't care. I didn't make this stuff up. However if they don't agree with this, THEY ARE WRONG!!!
01-09-2009, 03:59 PM
#40
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^Saying my car makes 200HP is almost as meaningless as saying it makes 200 ftlbs. A full plot vs. RPM of either is what you need to truly evaluate the performance of an engine.
The amount of torque your engine is making at any single instant in time is directly proportional to the amount of force applied to the wheels at that instant in time. F/m = a. As I said though, you need the full plot vs. RPM for it to be meaningful.
The amount of torque your engine is making at any single instant in time is directly proportional to the amount of force applied to the wheels at that instant in time. F/m = a. As I said though, you need the full plot vs. RPM for it to be meaningful.
01-12-2009, 01:58 PM
#46
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well... went to the dyno.
i don't know what to say...
i'll let you guys discuss....
byw, this was done at fast freddies (aka rotary reliability) in santa ana, ca.
i don't know what to say...
i'll let you guys discuss....
byw, this was done at fast freddies (aka rotary reliability) in santa ana, ca.
01-12-2009, 02:05 PM
#47
I don't have money to dyno all my cars, especially for a 1-10hp gain.
I've had it on a 00 civic, 04 Stang, 06 s2k, and now the AT6spd rx8. how do I know if this cutout thing help? simple, you line it up against an identical model, both stock and you run it. then, you run it with the cutout open see the difference. LOL
if you're wondering about the driver mod and driver error, I've tested at different speed and even played catch-up. The cutout helps mainly on top end. It will help you move better than the stock car resulting in hp and torque gain.
The cutout MUST be in front of the CAT for these kind of results. if there are no room, get a custom pipe build-out from your local muffler shop.
If you're curious about the system, the cut out is roughly 200. i think $200 beats a CAT system with 3inch piping and some fancy exhaust. Unless I'm on the track, I can just have the cutout bypass my stock system producing similar airflow. I can also drive it stock when I have my GF in the car as the OP mentioned.
Mike
I've had it on a 00 civic, 04 Stang, 06 s2k, and now the AT6spd rx8. how do I know if this cutout thing help? simple, you line it up against an identical model, both stock and you run it. then, you run it with the cutout open see the difference. LOL
if you're wondering about the driver mod and driver error, I've tested at different speed and even played catch-up. The cutout helps mainly on top end. It will help you move better than the stock car resulting in hp and torque gain.
The cutout MUST be in front of the CAT for these kind of results. if there are no room, get a custom pipe build-out from your local muffler shop.
If you're curious about the system, the cut out is roughly 200. i think $200 beats a CAT system with 3inch piping and some fancy exhaust. Unless I'm on the track, I can just have the cutout bypass my stock system producing similar airflow. I can also drive it stock when I have my GF in the car as the OP mentioned.
Mike
