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Trent250

Tuned extractors

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Measured the opening where it bolts to the head, so ports, and they were 42mm..

WOW 42mm ID and 50mm OD means 4mm wall, that's A LOT bonus is they should resist cracking a bit more.

The marks on the bottom are interesting as they start just after the bend but extend all the way along the pipe to near the flange, and even though the flange looks like its had a touch or 2 you would think that if the pipe has hit then flange would be smashed but it isn't. On my extractors I had a hell of a time trying to seal the pipes where they are really close as you just can't get in there to weld. I would be looking at cutting in the straight section before the last bend and putting in angled pieces to lift the rear section up a bit. This CAN'T be done without the extractors being on the car to make sure it passes the gearbox crossmember fine.

If you changed the transition between where the secondaries meet and the flange to join to the exhaust it would help a fair bit with performance, if you have a look around the internet at collectors and transitions you will get the idea. Will it make a difference yes but running what you have now will be fine until you want better.

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also noticed you use scorpion rockers .... good luck with them! LS1 guys been breaking them like pencils.

I have noticed that a lot of the LS crowd have trouble with a lot of the aftermarket gear in this area (including mega dollar parts), so is it a more of a case of stretching standard positioning rather than bad parts. I have heard of plenty of happy ford customers using scorpion rockers. I had planned to use them in a hydraulic crossflow until they no longer suited my changed setup and I sold them. I wouldn't expect them to compete with rockers that cost 1000's of dollars but I think they are good for the lower end of the performance market, I see it the same as expecting a 2 barrel carby to give 4 barrel performance it may happen but it really isn't a good idea.

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they used to buy the stampings from china few years back to save money, that din't work for them as both Comp and Scorpion started breaking, in order to keep Comp happy they started making them in the states but NOT all of them, some are still being forged outside of US and the blacks shipped over

 

It's hard to trust a brand these days as in order to stay in business they ultimately have to outsource and we pay the price. With everybody reading everybody's products it's a mess! I just seen them break both in LS1's and SBF's and i think someone here broke one as well

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Mine broke a few inlets rockers due to pusrod contact nothing more. Brancko uses Scorpian rockers on his 451 cube 850hp Windsor. They are a decent rocker and plenty strong.

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Correct me if I'm wrong but your extractors look to be made of mild steel with a HPC coating not stainless so any works you need to do to them will be much easier to source the right size pipe

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There's no way there stainless, they're rusting. They are hpc coated. The look like mine did when the coating fades. Used stainless headers dont look like that!!

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Never had anything to do with coated stuff, could it be a really low grade of stainless which is basically mild steel with some chromium thrown in to be able to be called stainless, it is even magnetic which true stainless isnt. Going off the measurements of 42mm ID and 50MM OD I wouldn't have thought mild steel pipe was that heavy walled, does the coating put on a thick skin?

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Extractors and exhaust systems can't be made from pretty shiny stainless because it has poor fatigue resistance from heat cycling and vibration (too much chrome makes it brittle). It cracks easily. Factory systems run a grade that forms surface rust but won't rust through. It has enough give in it to not crack like shiny stuff does.

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WOW 42mm ID and 50mm OD means 4mm wall, that's A LOT bonus is they should resist cracking a bit more.

The marks on the bottom are interesting as they start just after the bend but extend all the way along the pipe to near the flange, and even though the flange looks like its had a touch or 2 you would think that if the pipe has hit then flange would be smashed but it isn't. On my extractors I had a hell of a time trying to seal the pipes where they are really close as you just can't get in there to weld. I would be looking at cutting in the straight section before the last bend and putting in angled pieces to lift the rear section up a bit. This CAN'T be done without the extractors being on the car to make sure it passes the gearbox crossmember fine.

If you changed the transition between where the secondaries meet and the flange to join to the exhaust it would help a fair bit with performance, if you have a look around the internet at collectors and transitions you will get the idea. Will it make a difference yes but running what you have now will be fine until you want better.

What collector would u recommend? Like a longer one?

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Greg is the stainless your talking about magnetic, as far as I know there are a couple of different types of stainless that have the mechanical properties to be able to work on cars.

 

Trent I far from the right person to be asking regarding specific requirements and design. But what I can tell you is depending on the car ie gearbox, sump etc running the perfect parts in the exhaust is not always going to be possible. For example personally I think it is far more important to extend the secondaries than it is to use the perfect collector, and by extending the secondaries you run into clearance issues on a street car as the final collector finishes around the gearbox croasmember. Yes you can fit it but other compromises will then need to be made. I also think it is better to follow 1 idea all the way then try and combine parts of 2 or 3 ideas and end up nowhere or worse going backwards. Best advice I can give is find someone that has the knowledge and will listen to what YOU want and help you, not tell you what makes the most horsepower or sounds the best or looks the best or makes them the most money.

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Greg is the stainless your talking about magnetic, as far as I know there are a couple of different types of stainless that have the mechanical properties to be able to work on cars.

 

I believe the grade used on factory systems is magnetic. It would also be of a grade that isn't too hard on stamping tools and dies from a production point of view.

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Greg is the stainless your talking about magnetic, as far as I know there are a couple of different types of stainless that have the mechanical properties to be able to work on cars.

 

Trent I far from the right person to be asking regarding specific requirements and design. But what I can tell you is depending on the car ie gearbox, sump etc running the perfect parts in the exhaust is not always going to be possible. For example personally I think it is far more important to extend the secondaries than it is to use the perfect collector, and by extending the secondaries you run into clearance issues on a street car as the final collector finishes around the gearbox croasmember. Yes you can fit it but other compromises will then need to be made. I also think it is better to follow 1 idea all the way then try and combine parts of 2 or 3 ideas and end up nowhere or worse going backwards. Best advice I can give is find someone that has the knowledge and will listen to what YOU want and help you, not tell you what makes the most horsepower or sounds the best or looks the best or makes them the most money.

 

Well said bro...positive words

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Broken wheel those genie's are what we used to call genie speedways.  they are an interesting design but the secondaries need to be made pipe over cone to work more efficiently in my opinion.

 

good sensible advice wagon.  becoming and interesting thread. 

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What do you really want it for is the single biggest question that only about 5% actually do answer honestly or at all.The rest say max HP while it see's nothing but everyday driving all it's life.

 

For me the theory suggests a shorter pulse separation of the tri y pipes would be preferred over the 180 degree pipes but Mossy and Jase Stoodley are showing other wise with there max output combo's. What doe's this say...? That there's simply more than 1 way to skin a cat and the best way to find how you like yours skinned is bolt em on and make your own mind up.

 

I used a set of Genies but switched to some Pacemakers for mine and havn't looked back. 

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What do you really want it for is the single biggest question that only about 5% actually do answer honestly or at all.The rest say max HP while it see's nothing but everyday driving all it's life.

 

Couldn't agree with this more. Your application is your application regardless if your doing the same racing or cruising or what as other people. You know what you want from your car but answering the question really honestly will always result in a car you always enjoy.

 

 

 

That there's simply more than 1 way to skin a cat and the best way to find how you like yours skinned is bolt em on and make your own mind up.

 

You can even apply this on the way you modify your extractors. If an increase in torque sounds like your thing then extending the secondaries will do that, if optimising the engine in the upper rev range sounds like your thing look at stepped headers and cone design. If you are not quite sure which one you want or really aren't chasing a certain engine characteristic don't modify the extractors now. The extractors as they are now are still well built and use good sound performance thinking, sure they are not perfect but nothing is ever perfect as there are always compromises. Perfect example of this is in the article Sly posted about the pro stock cars, they use 2 different carby setups one for track and one for dyno. When using the track carby the engine loses 30-40hp but they have to use the track carby because it is setup run the car while coping with the g forces of running down the track, if professional pro stock teams have to compromise 30-40hp to make something work in the real world then I'm sure we all can put up with than 3-5% power drop in the real world. On a 350hp engine 3% is 10.5hp and 5% is 17.5hp on a 200 hp engine 3% is 6 hp and 5% is 10hp, can't see an engine losing that much horsepower because you didn't have the absolute optimal setup.

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I believe the grade used on factory systems is magnetic. It would also be of a grade that isn't too hard on stamping tools and dies from a production point of view.

 

The grade used in most exhaust systems is 410/420 (can't remember which one off the top of my head), and as has been mentioned before it has a slightly lower chrome content so it corrodes on the surface. The flip side of having lower chrome is less stresses from forming, i.e. bending and rolling for the muffler housings, and the corroded layer actually stops any further corrosion from forming. Both 410 and 420 stainless are magnetic as well.

 

For those who like a bit of light metallurgical reading...

 

http://www.interlloy.com.au/our-products/stainless-steel/410-martensitic-stainless-steel-bar/

 

 

http://www.interlloy.com.au/our-products/stainless-steel/420-martensitic-stainless-steel-bar/

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Thanks for the links mate. What is the benefit of making exhaust stuff out of stainless? Or at least what are people told is the benefit? From reading the spec sheets I have no idea why anyone would use either 410 or 420 to make any part of an exhaust. Not only do they lose their stainless properties when heated to near/over 650 degrees (420 has a max working temp of 400 degrees) but welding the stuff is a nightmare. 420 states that you shouldn't weld it as it air hardens so quickly and 410 can be welded but the procedure to stop cracking makes it pointless to use. To weld it properly it would take 10-12 days just to weld the primaries onto the flange for a crossflow, then you would need to heat treat after that which would be another 5-6 days. There is no way anyone would go to that much trouble for a set of headers and I highly doubt anyone making them would have the ovens and lime boxes to do the job properly.

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The 2 pics below are the reason I don't think the above stainless is suitable for exhaust. Also keep in mind that when metal is at different temperatures it expands and contracts at different rates, so the black areas on the exhaust below are much much cooler than the coloured sections. When metal expands and contracts at different rates it cracks, more so in harder steels

 

exhaust_technology_01.jpg

 

 

From what I have learned/been shown (by blacksmiths with over 40 years working experience) the temps are a little off on the below chart but give a pretty good indication of temps when metal turns to a certain colour

 

83011518.png

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Yeah, i thought the same when i first heard that manufacturers were using 410/20 stainless. That amount of chrome just makes any alloy brittle when hot. But they must have their reasons.

 

As far as why people want stainless exhausts, i think they believe that the mild exhaust is going to rot out on the quicker than stainless. But then i thought they aluminised the outside of exhaust tube to stop the corrosion issues..? I dunno. I just patch up whatever the car comes with when i buy it.

 

Personally i just buy the aluminised stuff and run it. Not had a problem yet.

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I just had a bit of a search around seeing what people say about stainless. Looks like everyone is pushing their own product as some say 304 grade is better others 309 and so on. They all say that the use of stainless exhaust is to extend the life of the exhaust due to not rusting. Stainless is most likely fine to use the further away from the extractors it is and in mufflers where moisture can build up and sit.

 

In saying all this though there is nothing bad about stainless, it's just when looking a buying extractors in stainless you need to check the spec sheet of the metal use to make the extractors to make sure it fits the application. The stainless shouldn't hurt performance and you just need to be aware of the cracking issues. Don't go spraying water or something on the extractors or in the bay unless everything is dead cold.

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My Proflow Cleveland extractors on my black ute are made from 316,

from memory stainless works in usa say, 316 is better for regular hi temp conditions like race extractors or turbo manifolds & 304 for exhausts

my AU utes extractors are 304 and where fitted 3 years ago. As is the 100 cell cat section I made for it and 7 year old 3" twin tip.

which is 2nd hand milk line from a dairy supplies place, my dad worked it cost 1/2 price of new tube.

IMG_2355_zpsbd5da73d.jpg

72_zps8bc2aa6d.jpg

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