Look what the mazda guys have been up to...

[Azza]

As Bren said, let's see how it goes when you get the thing on the road.

All I know is the stock system on my car put out a certain amount of power. Using a less restrictive exhaust (ie taking off the rear muffler and fitting the terrorist pipe) proved no difference in power.

Since adding the CES, I have noticed that my car certainly has gains that can be felt. If time permits, while I am down that way next week, I will have the car back on the Dyno for a new reading.

At the end of the day, as Lordy said, a stock system is designed to be cheap and quiet, so spending money on a less restictive system (without going too big) will assist in allowing your vehicle to achieve a slightly higher power output than what it did with the stock system.

Goodnight all

xoxoxox

[LordWorm]

As Bren said, let's see how it goes when you get the thing on the road.

Yeah not gunna put it on the "road" so to speak... the damned thing is loud (like hear it from the next suburb loud)...ear splitting, gut wrenchingly loud....

Looks like we'll be renting out archie's dyno soonish though - got a few cars that need a tune and i'm chasing a horrible timing gremlin...so i'll be sure to back to back it vs stocko system.

another point which hasn't been made, this pipe is lighter than the standard exhaust system. So it might only make me another handful of kW at peak power, but its going to save me quite a few kg as well.

[Azza]

As Bren said, let's see how it goes when you get the thing on the road.

Yeah not gunna put it on the "road" so to speak... the damned thing is loud (like hear it from the next suburb loud)...ear splitting, gut wrenchingly loud....

Looks like we'll be renting out archie's dyno soonish though - got a few cars that need a tune and i'm chasing a horrible timing gremlin...so i'll be sure to back to back it vs stocko system.

another point which hasn't been made, this pipe is lighter than the standard exhaust system. So it might only make me another handful of kW at peak power, but its going to save me quite a few kg as well.

Lighter hey? The first exhaust made from cardboard.....

Be sure to bring it to the next CES Dyno day won't ya....

Alsso, you want loud...did you ever hear the terrorist pipe, Shao can tell ya about it

[LordWorm]

As Bren said, let's see how it goes when you get the thing on the road.

Yeah not gunna put it on the "road" so to speak... the damned thing is loud (like hear it from the next suburb loud)...ear splitting, gut wrenchingly loud....

Looks like we'll be renting out archie's dyno soonish though - got a few cars that need a tune and i'm chasing a horrible timing gremlin...so i'll be sure to back to back it vs stocko system.

another point which hasn't been made, this pipe is lighter than the standard exhaust system. So it might only make me another handful of kW at peak power, but its going to save me quite a few kg as well.

Lighter hey? The first exhaust made from cardboard.....

Be sure to bring it to the next CES Dyno day won't ya....

Alsso, you want loud...did you ever hear the terrorist pipe, Shao can tell ya about it

Yes lighter than stock

stock's first cat is inside some big cast iron piece, weighs an absolute tonne

I never heard the terrorist pipe.... but yes, my pipe is loud..there is absolutely nothing muffling the sound... just like any open exhaust i guess.

[CAP]

If shao's was running through a cat and primary resonator, this will be quite louder again.

[Azza]

The terrorist pipe was an exchange to the stock rear muffler, still running through the stock res & cat.

There was a youtube somewhere of my corolla coming off the hoist with nothing after the collectors.....although the recording didnt really pick up the sound, it gave an indication

[The Last Streetfighter]

I saw this and could not let it go without a comment.... or 2.

1: Semantics. Exhaust can't give you power, says Lordworm. Well, changing to a less restrictive one can certainly give you top end power. Has been proven on a Dyno. Stock exhaust = x kw . Better Exhaust = x+y kw. But to take LW's point of view, the new system just "Steals" less of the power you are already making. Because most of us are coming from a position of having a manufacturer's system, I think there is nothing wrong with saying we "gain" power from a better setup. We still have to stay within certain bounds to be legal, so we cannot have an open system anyway. In types of motor racing these rules are different so you have a different starting point.

2: I can't agree that the pressure pulse going back up the header to the valve is what is helping you. I believe you get a low pressure pulse that follows the high pressure pulse out of the cylinder (caused by the mass of gas that is moving away while you are closing the valve, i.e. pulling a vacuum on it self). When this High then Low compression wave hits corners (and to a lesser extent, when it expands to the ID of the pipe) then it will get a pressure wave reflected back to the valve. After the pressure wave hits the valve then the valve should open and the vacuum wave should have just hit the valve and the new pressure pulse should follow this double-reflected vacuum wave out. That is what I call positive scavenging. It is most effective in the primaries, and you will get a small secondary effect further down at the end of the secondaries.

3: You mention a few times the exhaust gases "Expanding" as they travel down the exhaust pipe. I would like to know what you mean by this? I understand the expanding that happens in the cylinder, but why do you think they keep expanding down the system? The only thing that I can think of is similar to the effect of pressure drop across an orifice.

4: I would like someone to explain to me the whole idea of "not enough Velocity." We know that Very high velocity causes increased Pipe friction losses and increased separation/turbulence losses. This is the "fighting to get out" thing. The faster you go, the worse it gets to the square of velocity. That is why muffler systems do not really affect down low torque but can have a big effect on up high power. But "too big a pipe" causing problems is not clear to me. As close as I can get to an answer is using Bernoulli's Principle, where at lower velocities, the pressure contribution to head is increased.

As an interesting note, when I ran my silvertop to the exhaust shop, with only primaries and secondaries on it, I heard 2 very distinct resonances through the rev range (that is, in between my multiple orgasms from the hawt sound and the physical vibration of my body...)

[SuperDave]

Also, you want loud...did you ever hear the terrorist pipe, Shao can tell ya about it

So can I :P

[LordWorm]

I saw this and could not let it go without a comment.... or 2.

1: Semantics. Exhaust can't give you power, says Lordworm. Well, changing to a less restrictive one can certainly give you top end power. Has been proven on a Dyno. Stock exhaust = x kw . Better Exhaust = x+y kw. But to take LW's point of view, the new system just "Steals" less of the power you are already making. Because most of us are coming from a position of having a manufacturer's system, I think there is nothing wrong with saying we "gain" power from a better setup. We still have to stay within certain bounds to be legal, so we cannot have an open system anyway. In types of motor racing these rules are different so you have a different starting point.

Correct, you can say its a "gain" over standard. But the exhaust system isn't "doing" anything to give you that gain. The doing is happening in the headers. Yes you "gain" power over stock, but you gain it by, as you say, robbing less of the power away after the collector. and my point of view is very much slanted towards racing..

2: I can't agree that the pressure pulse going back up the header to the valve is what is helping you. I believe you get a low pressure pulse that follows the high pressure pulse out of the cylinder (caused by the mass of gas that is moving away while you are closing the valve, i.e. pulling a vacuum on it self). When this High then Low compression wave hits corners (and to a lesser extent, when it expands to the ID of the pipe) then it will get a pressure wave reflected back to the valve. After the pressure wave hits the valve then the valve should open and the vacuum wave should have just hit the valve and the new pressure pulse should follow this double-reflected vacuum wave out. That is what I call positive scavenging. It is most effective in the primaries, and you will get a small secondary effect further down at the end of the secondaries.

Perhaps a more eliquent way of putting it, but its essentially exactly the same explaination as was copied from the burns stainless website. and yes that is how scavenging works. the vacuum from each exhaust pulse helps pull the next pulse out, as well as draw the next intake charge in.

3: You mention a few times the exhaust gases "Expanding" as they travel down the exhaust pipe. I would like to know what you mean by this? I understand the expanding that happens in the cylinder, but why do you think they keep expanding down the system? The only thing that I can think of is similar to the effect of pressure drop across an orifice.

The gas "expands" to fill its container, being the collector, and the exhaust pipe. This expansion slows the gas down, and cools it. Yes you get explosive expansion inside the cylinder when it goes bang. It will also expand to fill its container as it leaves the combustion chamber. Puff a small bit of smoke (or a visible gas of some sort) into container, and seal the lid... what happens? the smoke eventually expands to fill the container. Same thing happens in the exhaust system. I'm reaching back a bit to my junior science classes, but from memory, a gas will always expand to fill its container. container gets bigger (so going from 1.25in primarys to a 2.5in collector), gas expands.

Oh and I didn't say it, again, quote from Burns Stainless website.

As an interesting note, when I ran my silvertop to the exhaust shop, with only primaries and secondaries on it, I heard 2 very distinct resonances through the rev range (that is, in between my multiple orgasms from the hawt sound and the physical vibration of my body...)

You're game - not only to drive essentially an open exhaust system on a public road, but to drive it hard enough to listen to the majority of the rev range :P

[black200]

backpressure is important for throttle response

[The Last Streetfighter]

Lol, I'm still not sold on this expanding gas theory. That would assume that the pipe is in vacuum to start with.

The gas will only expand if it is heated up or it is throttled.

Yeah I had to drive to the exhaust shop on a Sun Morn to get a cat and extension fitted. Wasn't going to get a tow just for that. Coopers Plains to Slacks Creek isn't far.

[CHA54]

I've also had to drive a car with open headers to the exhaust shop, nothing after the secondaries. Car had no power at all up to about 5500rpm, that's as high as I took it.

[Azza]

I've also had to drive a car with open headers to the exhaust shop, nothing after the secondaries. Car had no power at all up to about 5500rpm, that's as high as I took it.

I'm sure you never went higher than that.... :P

[CHA54]

took it to 8200 as soon as the exhaust was finshed :P

[SILVABULLIT]

Drove one of our Civic's with just headers on to the exhaust shop many a year ago. It was really loud and if you got off the throttle quick it would shoot flames out under neath which was pretty exciting but it lost a hell of a lot of power not just low down even noticable at the top end(9200rpm)

[Azza]

So does anybody know how this thing went? I heard it was making an appearance at MiniJam....

[SILVABULLIT]

From what I can remember from the day was that Lordworm qualified last in all motor and didn't make the 14.99 cut off but was still allowed to run due to not too many competitors. He came and had a chat with me and said that he set a new pb for MPH and ET(something like 15.2@89) with the crazy loud as exhaust and some more weight reductions. (should be on the biggest loser!!) So now he should be able to amost give a Stock Sportivo a good run for it's money!!

Had another mate up there with a beetle with 1585cc motor with webers, cam, light flywheel and any other part he could scab 2nd or 3rd hand from some other mates and put this engine together(all up motor cost him a few hundred $$). Took all the crap out of his car and had trouble launching it due to major axle tramp causing it to jump out of 1st gear. So he drove it slowly off the line then into it and managed to run a respectable 14.89@89.?mph. Pretty darn good effort for a small motor.

On the other hand one of my other mates won All Motor with his VW and reset the national record with 11.40 @118.2mph. Congrats Dave and well done!!

[Azza]

15.2 ????

Gee, haven't we had stock Sportivo's doing high 14's?

[Red_CT9A]

not afaik

the quickest STOCK (ie nothing done) i know of is super dave's car, he pulled a 15.1 if i remember correctly

u guys can check in the 1/4 mile database

[SILVABULLIT]

not afaik

the quickest STOCK (ie nothing done) i know of is super dave's car, he pulled a 15.1 if i remember correctly

u guys can check in the 1/4 mile database

Wei.... 85ish civic with K20 ran 11.67@116mph!! Bit quicker than some of the boys from POV?? what do they run??

[LordWorm]

From what I can remember from the day was that Lordworm qualified last in all motor and didn't make the 14.99 cut off but was still allowed to run due to not too many competitors. He came and had a chat with me and said that he set a new pb for MPH and ET(something like 15.2@89) with the crazy loud as exhaust and some more weight reductions. (should be on the biggest loser!!) So now he should be able to amost give a Stock Sportivo a good run for it's money!!

Had another mate up there with a beetle with 1585cc motor with webers, cam, light flywheel and any other part he could scab 2nd or 3rd hand from some other mates and put this engine together(all up motor cost him a few hundred $$). Took all the crap out of his car and had trouble launching it due to major axle tramp causing it to jump out of 1st gear. So he drove it slowly off the line then into it and managed to run a respectable 14.89@89.?mph. Pretty darn good effort for a small motor.

On the other hand one of my other mates won All Motor with his VW and reset the national record with 11.40 @118.2mph. Congrats Dave and well done!!

second to last qualifier...there was a dub according to the seeding chart (not sure if it was one of your lot) that went slower than me, but not sure if he hung around for the racing (assuming he broke something or was just out there for sh!ts and giggles)

none of the cut off times are being enforced this season - appart from the front mod cut off, which if you go over you get bumped to street front and have to pull off your slicks....combined class tho so it doesn't really matter, hence why i entered in the first place. Jamboree saw 40 odd cars in street rear, the slowest being some volvo at over 20 seconds, and it was allowed to race.....its all well and good to have cut offs, but until ray gets a decent following, he's not gunna turn entrants away.

I wouldn't have put it in if i wasn't going to be allowed to race it. Was a good day out... i was taken out in the quarters because i redlit against that insane alcorn red rocket (if that thing doesn't end up with the national record in the near future i'll eat my hat...they havn't even really begun to touch that K20A - still on standard cams, with a head that'll flow happilly with far more lift and duration - still standard compression, still standard redline...in a car that when wringing wet is only 25kg short of the weight break with driver....that thing will move)

I'm hunting anyone who happened to video my car at all...apparently the insane pipe was blowing blue fireballs while i rattled it off the rev limited on a burnout.

was a great day out... big thanks to the vee dub boys for loaning me an air compressor and being good fellas all day, cheers to Brenndan for the chat, cheers to ray for a good event, and to the willowbank guys for a brilliant track....

[Azza]

Essentially though LW, the pipe you made appears to have done nothing but given you (and the spectators) a great giggle yeah?? No improvement in time or power.....

[LordWorm]

Essentially though LW, the pipe you made appears to have done nothing but given you (and the spectators) a great giggle yeah?? No improvement in time or power.....

3 tenths of a second improvement in time, but that could be down to a lack of exhaust system (bit of weight there).

Definantly definantly DEFINANTLY more power though, engine required about 4% increase in fuel across the entire tune to burn in the right air fuel range, which is an indication that more exhaust gas is being evacuated in a more effecient way, thus more space for air in the cylinder, thus a requirement for more fuel...and so more power. Car also wasn't "retuned" as such for the pipe, all we did was adjust MIX_TRM by +4%, so there was a flat spot around 4500rpm that was quite noticable

MPH is also one of the biggest indications of increased power, and that was up by nearly 3mph.

so yes, considerable improvement to top end, and allowed me to run the car upto a revised rev limit (600rpm over stock) without it starving itself for air (again, something i can't do on the standard pipe, it just runs out of legs at about 6300rpm normally) - i do normally drive it to the revised rev limit on the track, but mainly for gearing advantage on the next change, but this time i was definantly making more power up there, and was getting a benifit out of a slightly bigger top end.

didn't see anyone giggling, not that i'd give a **** if they were.

Edited April 3, 2007 by LordWorm

[SILVABULLIT]

From what I can remember from the day was that Lordworm qualified last in all motor and didn't make the 14.99 cut off but was still allowed to run due to not too many competitors. He came and had a chat with me and said that he set a new pb for MPH and ET(something like 15.2@89) with the crazy loud as exhaust and some more weight reductions. (should be on the biggest loser!!) So now he should be able to amost give a Stock Sportivo a good run for it's money!!

Had another mate up there with a beetle with 1585cc motor with webers, cam, light flywheel and any other part he could scab 2nd or 3rd hand from some other mates and put this engine together(all up motor cost him a few hundred $$). Took all the crap out of his car and had trouble launching it due to major axle tramp causing it to jump out of 1st gear. So he drove it slowly off the line then into it and managed to run a respectable 14.89@89.?mph. Pretty darn good effort for a small motor.

On the other hand one of my other mates won All Motor with his VW and reset the national record with 11.40 @118.2mph. Congrats Dave and well done!!

second to last qualifier...there was a dub according to the seeding chart (not sure if it was one of your lot) that went slower than me, but not sure if he hung around for the racing (assuming he broke something or was just out there for sh!ts and giggles)

none of the cut off times are being enforced this season - appart from the front mod cut off, which if you go over you get bumped to street front and have to pull off your slicks....combined class tho so it doesn't really matter, hence why i entered in the first place. Jamboree saw 40 odd cars in street rear, the slowest being some volvo at over 20 seconds, and it was allowed to race.....its all well and good to have cut offs, but until ray gets a decent following, he's not gunna turn entrants away.

I wouldn't have put it in if i wasn't going to be allowed to race it. Was a good day out... i was taken out in the quarters because i redlit against that insane alcorn red rocket (if that thing doesn't end up with the national record in the near future i'll eat my hat...they havn't even really begun to touch that K20A - still on standard cams, with a head that'll flow happilly with far more lift and duration - still standard compression, still standard redline...in a car that when wringing wet is only 25kg short of the weight break with driver....that thing will move)

I'm hunting anyone who happened to video my car at all...apparently the insane pipe was blowing blue fireballs while i rattled it off the rev limited on a burnout.

was a great day out... big thanks to the vee dub boys for loaning me an air compressor and being good fellas all day, cheers to Brenndan for the chat, cheers to ray for a good event, and to the willowbank guys for a brilliant track....

Mate only one of the VW's went slower than you in one practice run. All others he was quicker and in the 2 rounds of racing he competed in he ran 14.89 and 14.95. not bad for a 1585 cc engine made of 2nd and 3rd hand bits!! Morgan Smith dropped a rod in qualifying so he didn't compete at all. didn't get any pics of you or video as I was busy pushing cars and staging them at the same time you ran. Poor ol twiggy got sand bagged by Dave Homer!!! Bit Cheeky I thought.....

[Red_CT9A]

not afaik

the quickest STOCK (ie nothing done) i know of is super dave's car, he pulled a 15.1 if i remember correctly

u guys can check in the 1/4 mile database

Wei.... 85ish civic with K20 ran 11.67@116mph!! Bit quicker than some of the boys from POV?? what do they run??

big congrats to the AH K20 for pulling that time.....just fyi that ET now puts them and their car as the 2nd fastest NA FWD Street Tired car in the WORLD!!!!!!! HUGE achievement!!!!!!

the quicker cars from POV are very capable of pulling high 12s but due to lack of traction have only managed low to mid 13s (i say they are capable of 12s bcos their MPH puts them in the 12 second zone)

also a few of the POV boys have ditched their old motors and gotten new ones, namely a JDM K20A, K24 and a B18C-T which will be pushing around 250 KW ATW

so yeah good times ahead ;)