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Yoshimura RS-4 any difference between Stainless and Titanium

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I was all set to buy a Yoshimura RS-4 Titanium exhaust for my 2011 CRF250 but after looking at the cracks in my Lightspeed bash guard I think I would be better suited to their stainless system.

I am pretty sure they are the same exhaust except for the materials they are made out of, but I was just wondering if anyone could could tell me if there is any difference (apart from the weight) between the RS-4 Titanium/Carbon Full System and the RS-4 Stainless/Aluminum Full System?

And Is there any difference in power between the two systems?

I don't want to buy the stainless system only to find out that the Titanium makes more power?

Thanks for you help.

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I have the titanium system on my 2010 fit and finish is excellent.The weld do not hang over into the inside of the pipe.I recently purchased the stainless system for my 2011 450 and you can see why it's so much cheaper.The weld have a lot of left over material on the inside of the pipe.Enough that it would cause a hp loss.Sure it's not much but on a 250 every bit counts.I would spend the extra coin on the titanium system.

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Thanks for the advice. Its not the money its more the fact that the titanium pipe will get damaged from rocks and the carbon mufler will get cracks and the header will get dented.

My lightspeed bash guard has chips in it and is actually cracked in one spot from roost and rocks flicking up off the front wheel after just two races.

The dirt at my local tracks is basically road because they are located in a quarry.

How has your titanium pipe held up, has it been dented?

Thanks

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I have the titanium system on my 2010 fit and finish is excellent.The weld do not hang over into the inside of the pipe.I recently purchased the stainless system for my 2011 450 and you can see why it's so much cheaper.The weld have a lot of left over material on the inside of the pipe.Enough that it would cause a hp loss.Sure it's not much but on a 250 every bit counts.I would spend the extra coin on the titanium system.

I call bs on "robbing hp"

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My titanium header has held up great.There are a couple of tracks my son races at that has some rock mixed in the dirt but the pipe hasn't gotten dented yet.I also run the carbon fiber muffler and the carbon fiber has been hold up good also.The exhaust has 40 racing hours on it.That bike only gets used for racing no practice or play riding.

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I have the titanium system on my 2010 fit and finish is excellent.The weld do not hang over into the inside of the pipe.I recently purchased the stainless system for my 2011 450 and you can see why it's so much cheaper.The weld have a lot of left over material on the inside of the pipe.Enough that it would cause a hp loss.Sure it's not much but on a 250 every bit counts.I would spend the extra coin on the titanium system.

I call bs on "robbing hp". You not going to notice any difference at all. Material welds will not cause hp loss, unless the diameter is closed off in some sort of fashion. I hardly believe they are that much in difference other than strength and weight.

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I call bs on "robbing hp"

Maybe only a dyno would tell.But any obstruction in exhaust flow can cause a hp loss.Might not be much and probably only a dyno could show the difference.

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Its a damn dirtbike! For goodness sake, if your a pro AMA rider I'd understand but damn it man. Just ride the freaking thing. When did It become that important to gain hp and loose weight for the avg Joe?? Let me dyno my lawn tractor with Ti blades on it and see if I gained hp over stainless.

OP your wasting your money if you don't know the answer to your own question.

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Thank you for your opinions. I think I will go stainless and spend the money on other mods.

Thanks for your help.

Ari

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Thank you for your opinions. I think I will go stainless and spend the money on other mods.

Thanks for your help.

Ari

Good choice.

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Good choice.

Look up torque step headers. It's automobile header technology. I'm surprised that they haven't taken it to the motorcycles yet. It's been out for a number of years and a lot of research has been done on it and it works. Pretty impressive HP gains on a 400 HP SBC. Don't know if it would make much of a difference on a 35 hp dirt bike engine, but the theory itself makes sense.

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Look up torque step headers. It's automobile header technology. I'm surprised that they haven't taken it to the motorcycles yet. It's been out for a number of years and a lot of research has been done on it and it works. Pretty impressive HP gains on a 400 HP SBC. Don't know if it would make much of a difference on a 35 hp dirt bike engine, but the theory itself makes sense.

Charlie, I know about them. For those that don't know, this should be a close (stolen) example.

The idea behind a stepped header is to maintain optimal port/exhaust gas velocity across all RPMs.

The issue with the current headers offered is that the primary tubes are significantly larger than the ports they mate up to. This sudden change in diameter from port to primary allows the exhaust gasses to expand rapidly AND their velocity to slow. Its this loss of velocity which robs the engine of its low-end torque. A successful stepped header design would change diameter such that torque would increase across the entire RPM range instead of having a big hole in the low-mid range.

A stepped header features primary and secondary collectors with dramatic changes in tube diameter. These changes occur at strategic points/sections of collector. The visual effect is a pronounced 'step' where the smaller & larger diameter tubes meet. The performance effect is a broader overall torque curve with specific emphasis on lower RPM pulling power & increased RPM recovery rates when shifting.

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When I had my trx450r there was a company that was doing that though I don't recall who it was.

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Charlie, I know about them. For those that don't know, this should be a close (stolen) example.

The idea behind a stepped header is to maintain optimal port/exhaust gas velocity across all RPMs.

The issue with the current headers offered is that the primary tubes are significantly larger than the ports they mate up to. This sudden change in diameter from port to primary allows the exhaust gasses to expand rapidly AND their velocity to slow. Its this loss of velocity which robs the engine of its low-end torque. A successful stepped header design would change diameter such that torque would increase across the entire RPM range instead of having a big hole in the low-mid range.

A stepped header features primary and secondary collectors with dramatic changes in tube diameter. These changes occur at strategic points/sections of collector. The visual effect is a pronounced 'step' where the smaller & larger diameter tubes meet. The performance effect is a broader overall torque curve with specific emphasis on lower RPM pulling power & increased RPM recovery rates when shifting.

I had a feeling you knew what they were. The theory applies through this thread (argument) with the dents and welds of the exhaust systems.

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If you get the stainless pipe make sure to at least get the 99db insert otherwise you are just getting the pipe for pretty and not power. According to a tech at yosh (via TT post) the stainless pipe makes the same power as the stock pipe as long at it has the 96dB insert. Ron Hamp also days that the Yoshi pipe (stainless or otherwise) made the most power without the insert or ring if you can deal with it being about 104dB instead of 99dB.

Just summing up a couple of post that I read when I researched the RS4 for my '10. My Ti pipe has held up great and fit perfectly. If you wanna save some money, try the hookit.com website and apply for the yoshi grassroots sponsorship. You'll pay about 60% of the retail price.

jeff

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If you get the stainless pipe make sure to at least get the 99db insert otherwise you are just getting the pipe for pretty and not power. According to a tech at yosh (via TT post) the stainless pipe makes the same power as the stock pipe as long at it has the 96dB insert. Ron Hamp also days that the Yoshi pipe (stainless or otherwise) made the most power without the insert or ring if you can deal with it being about 104dB instead of 99dB.

Just summing up a couple of post that I read when I researched the RS4 for my '10. My Ti pipe has held up great and fit perfectly. If you wanna save some money, try the hookit.com website and apply for the yoshi grassroots sponsorship. You'll pay about 60% of the retail price.

jeff

I was planning on pulling all the inserts and spark arrestors out, so I thought if I did this then it would make the same power as the Ti?

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Yes. It is reported that the stainless makes the same power as Ti with no insert.

And the stepper header thing.... they do not work in all applications with all cylinder head designs, port designs, exhaust valve angles, combustion chamber designs and RPM ranges. It is not a universal application but is viable in many cases. You will see them on every single F1 car and at the same not see them on about half the field of ALMS entries. Hopefully one day a the MX exhaust manufacturers will give us the R&D that we pay these ridiculous prices for. Maybe we'll see them start to show up.

jeff

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I would prefer to buy the stainless system I am just checking that you can take out the 96DB/99DB inserts out of the stainless system and just run it wide open with no inserts?

I would pull the AMA DB insert out of the Ti system anyway because I am not really worried about how loud it is as long as it makes the same power as the Ti system with its DB inserts out.

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Yes. It is reported that the stainless makes the same power as Ti with no insert.

And the stepper header thing.... they do not work in all applications with all cylinder head designs, port designs, exhaust valve angles, combustion chamber designs and RPM ranges. It is not a universal application but is viable in many cases. You will see them on every single F1 car and at the same not see them on about half the field of ALMS entries. Hopefully one day a the MX exhaust manufacturers will give us the R&D that we pay these ridiculous prices for. Maybe we'll see them start to show up.

jeff

That says it all!

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When I had my trx450r there was a company that was doing that though I don't recall who it was.

dasa was the company

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