Sound(noise for those that don’t like petrol!) isn’t rpm dependent.

i guess they took a 70’s design, took some more modern thinking, ran numerous versions on a dyno, looked as how packaging effected output, also build cost, then picked something that left the finance department happy while offering a packaging and performance improvement. It’s quite a change from the cheaper/older version you can get(which I don’t know why people still buy).

13 minutes ago, Jason240z said:

Sound(noise for those that don’t like petrol!) isn’t rpm dependent.

LOL, you're 'confused' but still guessing ?

So, the answer is you/nobody know what changes they made to improve but are we sure that they have dropped the H-crossover ? That might be THE major improvement if pipe-size hasn't changed ?

But now I'm confused when you claim sound levels are rpm dependant.....are you sure that you meant that ?

Yes, totally, I had a 749r that made more noise on track side tests at 7000rpn than it did at 8500rpm.  Stuff I don’t under stand, resonant frequency/harmonics etc etc.

no they’ve not said where the improvement comes, They’re hardly going to give you a ‘how to guide’.

37 minutes ago, Jason240z said:

Yes, totally, I had a 749r that made more noise on track side tests at 7000rpn than it did at 8500rpm.  Stuff I don’t under stand, resonant frequency/harmonics etc etc.

no they’ve not said where the improvement comes, They’re hardly going to give you a ‘how to guide’.

I disagree and so do Fujitsubo having measured different dB levels at different engine revs so ipso facto - sound levels ARE rpm dependant.

I don't what it'll cost them to state what they've changed between the old and new system......

46 minutes ago, Sean Dezart said:

...you/nobody know what changes they made to improve but are we sure that they have dropped the H-crossover ? That might be THE major improvement if pipe-size hasn't changed ?

Sean, where's the data regarding pipe size? A little bit further back up-thread you were quoting *STOCK* Nissan twin pipe system pipe diameter, but I am 100% sure the Fujitsubo systems use a bigger pipe diameter than that. Where are you getting your data from?

Another thing: There seems to be a discrepancy between what the re-sellers (RHD Japan & Whitehead Performance?) are claiming about applicable models. I notice that Fujitsubo themselves are quoting fitment on chassis made between 1969 (Showa 44) and September 1975 (Showa 50-9). Caveat emptor.

Also, "stock L20"? Where's that come from? 

 

In my opinion you're in danger of throwing a bit too much shade in Fujitsubo's direction. As a manufacturer/supplier of competing product, you have a dog in this fight. If I were you I'd concentrate on your own product and let the market decide. 

 

   

4 minutes ago, HS30-H said:

Sean, where's the data regarding pipe size? A little bit further back up-thread you were quoting *STOCK* Nissan twin pipe system pipe diameter, but I am 100% sure the Fujitsubo systems use a bigger pipe diameter than that. Where are you getting your data from?

Another thing: There seems to be a discrepancy between what the re-sellers (RHD Japan & Whitehead Performance?) are claiming about applicable models. I notice that Fujitsubo themselves are quoting fitment on chassis made between 1969 (Showa 44) and September 1975 (Showa 50-9). Caveat emptor.

Also, "stock L20"? Where's that come from? 

 

In my opinion you're in danger of throwing a bit too much shade in Fujitsubo's direction. As a manufacturer/supplier of competing product, you have a dog in this fight. If I were you I'd concentrate on your own product and let the market decide. 

 

   

Hi Alan.

I have no data  - you said that you'd check the OEM Nissan twin-pipe diameters and I'm hoping someone on here with a Legalis system will come forward and volunteer the current pipe diameters. Until then, one can only speculate upon where the improvements originated but it was mentioned by someone else that an H-crossover wasn't ideal for inline engines....I didn't say that !

Stock L20 ? Well, here : https://www.fujitsubo.co.jp/prods/detail/000000000000002298/00000000000000005120/00001708

Mentions L20 and also having obtained 95ps at 4670 revs - that surely has to be a stock engine Alan ?

I respect your opinion (perhaps of my intention) but you're wrong and I've said it twice already but I'll repeat it - I'm not knocking their product - it's a great piece of kit that has been successfully fitted to non-JDM and bigger engined cars.

 

Sean, what you should do is spend a few days on a dyno, comparing your systems, trying size of pipe work and routing types with mock setups, see what works where and why.

 

and yes, noise as measured can lower at higher rpm, as proven by noise testers ?

3 minutes ago, Jason240z said:

Sean, what you should do is spend a few days on a dyno, comparing your systems, trying size of pipe work and routing types with mock setups, see what works where and why.

This has already been suggested on your local site and I said I could supply but I'm not a full-time pro mate - like you I have a day-job, kids, wife.....we can only do what we do !

Talking again of Fujitsubo : http://www.speedhunters.com/2018/04/the-3-5l-240z-you-didnt-see-coming/

7 minutes ago, Sean Dezart said:

This has already been suggested on your local site and I said I could supply but I'm not a full-time pro mate - like you I have a day-job, kids, wife.....we can only do what we do !

Talking again of Fujitsubo : http://www.speedhunters.com/2018/04/the-3-5l-240z-you-didnt-see-coming/

What’s that got to do with fujitsubo?

Ah, I know something you don't then

2 minutes ago, Sean Dezart said:

Ah, I know something you don't then

It’s not my bag ?

FB PM me if you like.