hey guys i did a quick search couldn’t find anything at work right now 
I was gonna order rs-r off my local shop but they said the piping is not stainless that it is mild.
Greddy sp2 is full stainless… is that true that rs-r is not full stainless that parts of it is mild steel (piping).
Thanks.
well the add claims full stainless and so does the tanabe ad.
might be true since it is coated all the way to the tip and uses SUS409 SS which means it has some sort of other metal mixed in with it. i know the old school rsr is SS.
YES. I contacted them, the whole piping, muffler, and tip is stainless steel. It is black bc it is a ceramic coating.
The old schoool version only has the axle back portion polished (not coated), while the b-pipe is coated and thus black just like the newer RS*R’s.
I kinda like the black better myself.
if the SS is anything but 304SS it is a mixture of SS & another metal to cut on cost and actually can rust hence the jet black coating.
alright thanks for all the posts… i’ll have to read up more on the 409 vs 304 ss… i know greddy is all 304… so that’s nice… and a good friend of mine has a tanabe on a eg civic and it hasn’t rusted in almost 4 years now.
Here is the jist of some quick research
409:
Corrosion Resistance
Grade 409 resists atmospheric and exhaust gas corrosion. A light surface rust will form in most atmospheres; this rust retards further corrosion but makes the surface undesirable for decorative applications. The corrosion resistance is about the same as that of 3CR12 and the 12% chromium martensitic grades such as 410, and inferior to the 17% chromium grade 430.
Heat Resistance
Generally 409 is classified as resistant to scaling in intermittent service up to 815°C and up to 675°C in continuous service, but these temperatures are dependent upon the exact service environment.
Heat Treatment
Annealing - heat to 790-900°C and air cool. This grade cannot be hardened by thermal treatment.
Welding
Readily welded but a pre-heat of 150-260°C is recommended. Grade 409 or Grade 430 electrode or filler rods can be used, but AS 1554.6 pre-qualifies welding of 409 with Grade 309 rods or electrodes. These austenitic fillers result in a more ductile weld.
Post-weld annealing at 760-815°C improves weld ductility.
Post-weld annealing is not required when welding thin sections. Automotive exhaust tubing is typically welded without filler metal (autogenously).
All welding must be carried out with minimum heat input to reduce grain growth effects.
Applications
Typical applications include:
·Automotive exhaust systems
·Catalytic converters
·Mufflers
304:
Corrosion Resistance
Excellent in a wide range of atmospheric environments and many corrosive media. Subject to pitting and crevice corrosion in warm chloride environments, and to stress corrosion cracking above about 60°C. Considered resistant to potable water with up to about 200mg/L chlorides at ambient temperatures, reducing to about 150mg/L at 60°C.
Heat Resistance
Good oxidation resistance in intermittent service to 870°C and in continuous service to 925°C. Continuous use of 304 in the 425-860°C range is not recommended if subsequent aqueous corrosion resistance is important. Grade 304L is more resistant to carbide precipitation and can be heated into the above temperature range.
Grade 304H has higher strength at elevated temperatures so is often used for structural and pressure-containing applications at temperatures above about 500°C and up to about 800°C. 304H will become sensitised in the temperature range of 425-860°C; this is not a problem for high temperature applications, but will result in reduced aqueous corrosion resistance.
Heat Treatment
Solution Treatment (Annealing) - Heat to 1010-1120°C and cool rapidly. These grades cannot be hardened by thermal treatment.
Welding
Excellent weldability by all standard fusion methods, both with and without filler metals. AS 1554.6 pre-qualifies welding of 304 with Grade 308 and 304L with 308L rods or electrodes (and with their high silicon equivalents). Heavy welded sections in Grade 304 may require post-weld annealing for maximum corrosion resistance. This is not required for Grade 304L. Grade 321 may also be used as an alternative to 304 if heavy section welding is required and post-weld heat treatment is not possible.
Machining
A “Ugima” improved machinability version of grade 304 is available in bar products. “Ugima” machines significantly better than standard 304 or 304L, giving higher machining rates and lower tool wear in many operations.
Dual Certification
It is common for 304 and 304L to be stocked in “Dual Certified” form, particularly in plate and pipe. These items have chemical and mechanical properties complying with both 304 and 304L specifications. Such dual certified product does not meet 304H specifications and may be unacceptable for high temperature applications.
Applications
Typical applications include:
· Food processing equipment, particularly in beer brewing, milk processing & wine making.
·Kitchen benches, sinks, troughs, equipment and appliances
·Architectural panelling, railings & trim
·Chemical containers, including for transport
·Heat Exchangers
·Woven or welded screens for mining, quarrying & water filtration
·Threaded fasteners
·Springs
i forgot this to:
Possible Alternative Grades
Possible alternative grades to grade 409 stainless steels are given in table 5.
Table 5. Possible alternative grades to 409 grade stainless steel
Grade
Why it might be chosen instead of 409
3CR12
Similar corrosion resistance, easier welding and more readily available than 409, particularly in heavy sections. (409 may have better drawability than 3CR12.)
304
Better corrosion resistance and heat resistance but at higher cost.
321
Higher heat resistance than 409 or 304.
Aluminised steel
Lower resistance to exhaust gases, but at lower cost than stainless steel grade 409.
Possible Alternative Grades
Possible alternative grades to grade 304 stainless steels are given in table 5.
Table 5. Possible alternative grades to 304 grade stainless steel
Grade
Why it might be chosen instead of 304
301L
A higher work hardening rate grade is required for certain roll formed or stretch formed components.
302HQ
Lower work hardening rate is needed for cold forging of screws, bolts and rivets.
303
Higher machinability needed, and the lower corrosion resistance, formability and weldability are acceptable.
316
Higher resistance to pitting and crevice corrosion is required, in chloride environments
321
Better resistance to temperatures of around 600-900°C is needed…321 has higher hot strength.
3CR12
A lower cost is required, and the reduced corrosion resistance and resulting discolouration are acceptable.
430
A lower cost is required, and the reduced corrosion resistance and fabrication characteristics are acceptable.