New Fujitsubo Exhaust System to be Released

[Sean Dezart]

Why wouldn't it be scaleable ?

Well, yes why not ? But are they available so commercially today ?

What were the internal diamter pipes offered by Nissan as OEM on PS30s and options on S30s please ?

 

Whitehead quotes : Featuring dual 2” stainless pipes

and RHDJapan for the Legalis system : Pipe Diameter: 50.8mm
 

but also :

COMPATIBILITY NOTES - Only For Nissan Fairlady Z S30 HS30 with L20 and L24 Engines.

I'm not sure packaging IS a big issue as these twin pipes are long and the overall package heavy at (source RHD) : Muffler Weight: Fujitsubo: 15.9kg 

whereas Ix I know well weighs in at 13.5kgs  (2-1 Y-pipe included)

 

I suspect but you can confirm this Alan that the OEM JDM twin-pipe system was of dual 50mm pipes then as now so any upscaling just hasn't happened. Maybe something to do with fitting confortably underneath the cars too......?

[HS30-H]

14 minutes ago, Sean Dezart said:

Why wouldn't it be scaleable ?

Well, yes why not ? But are they available so commercially today ?

What were the internal diamter pipes offered by Nissan as OEM on PS30s and options on S30s please ?

 

Whitehead quotes : Featuring dual 2” stainless pipes

and RHDJapan for the Legalis system : Pipe Diameter: 50.8mm
 

but also :

COMPATIBILITY NOTES - Only For Nissan Fairlady Z S30 HS30 with L20 and L24 Engines.

I'm not sure packaging IS a big issue as these twin pipes are long and the overall package heavy at (source RHD) : Muffler Weight: Fujitsubo: 15.9kg 

whereas Ix I know well weighs in at 13.5kgs  (2-1 Y-pipe included)

 

I suspect but you can confirm this Alan that the OEM JDM twin-pipe system was of dual 50mm pipes then as now so any upscaling just hasn't happened. Maybe something to do with fitting confortably underneath the cars too......?

Sean, half the time I can't work out what you're quoting and what is your original new text.

I'm pretty sure I measured the OEM twin pipe system for you before when you asked. I don't have measurements to hand right now, but can check later.

In the meantime, I'll ask the question again. Why would twin pipes not be scalable? You can't point at the Fujitsubo Legalis for an answer.

You said "I'm tempted to believe that dual pipes on an S30 are better suited towards the smaller cc engines (S20 and L20) than for larger." Based on what premise, exactly?  

 

[Sean Dezart]

6 minutes ago, HS30-H said:

I'm pretty sure I measured the OEM twin pipe system for you before when you asked. I don't have measurements to hand right now, but can check later.

Thanks and pretty sure you quoted twin 50mm.

8 minutes ago, HS30-H said:

In the meantime, I'll ask the question again. Why would twin pipes not be scalable? You can't point at the Fujitsubo Legalis for an answer.

I didn't say they couldn't be, merely that I haven't seen any commercially available aside from theFujitsubo Legalis which I quoted because :

a) we remain on topic and

b ) it appears to be the only twin-pipe system available (putting aside the 'twice-pipes' kit sold my MSA)

c) Fujitsubo are quoted as stating that thier twin-pipe system is only compatible with the 2.4 and under engine sizes

Of course, anyone can make up a larger-diameter twin-pipe system  but space IS tight under an early S30 floor - fitting larger diameter pipework is going to create fitting problems at multiple points if adequate ground clearance is to be maintained. Fujitsubo wisely re-worked theirs especially to improve this - going bigger might be going 'backwards' .

 

8 minutes ago, HS30-H said:

You said "I'm tempted to believe that dual pipes on an S30 are better suited towards the smaller cc engines (S20 and L20) than for larger." Based on what premise, exactly?  

To help generate low-end torque without penalising top-end power. Why else would Nissan fit them ?

And Fujitsubo appear to agree : "Only For Nissan Fairlady Z S30 HS30 with L20 and L24 Engines."

 

Are my quotes easier to read now ?

 

[HS30-H]

Sean, you're pointing to the fact that the Fujitsubo Legalis system is aimed at L20 and L24-engined cars (Japan didn't get L26 or L28 powered S30s) as confirmation of your premise that "dual pipes are better suited towards the smaller cc engines (S20 and L20) than larger". It simply doesn't follow.

If dual pipe systems on straight six engines, as you say, "...help generate low-end torque without penalising top-end power" then why is that not scalable to larger capacities than 2000cc and 2400cc? Where's the science to back that up?

 

Yes, the quotes are now much better!

[Jason240z]

2 hours ago, Sean Dezart said:

I'm tempted to believe that dual pipes on an S30 are better suited towards the smaller cc engines (S20 and L20) than for larger.

Whys that? Works for bmw on the s50 Range.  That’s over 100bhp per ltr. That alone should tell you it works, it’s half a Maclaren f1 engine.  Good enough for Nissan’s period race cars too.

[Jason240z]

That’s on 3.0/3.2 ltr na engines.

[Sean Dezart]

2 minutes ago, HS30-H said:

Sean, you're pointing to the fact that the Fujitsubo Legalis system is aimed at L20 and L24-engined cars (Japan didn't get L26 or L28 powered S30s) as confirmation of your premise that "dual pipes are better suited towards the smaller cc engines (S20 and L20) than larger". It simply doesn't follow.

No, I'm not - I've only just seen that and quoted it as it appears to back up my theory which I've held for ages !

I'm well aware that the JDM S30s were'n't supplied OEM with anything bigger than L24s and let's be clear here, I'm NOT knocking the Fujitsubo kit !!!

BTW, the North Amercian importer quotes this :

Application:

1970-1973 Datsun 240Z
1974-1974.5 Datsun 260Z
1975-1978 Datsun 280Z

And we've already discussed that list re diff suitability.

And you sir haven't answered my question upon why Nissan offered them in the first place.....

3 minutes ago, HS30-H said:

If dual pipe systems on straight six engines, as you say, "...help generate low-end torque without penalising top-end power" then why is that not scalable to larger capacities than 2000cc and 2400cc? Where's the science to back that up?

Nobody has said that a dual-pipe can't be scaled up in proportion to the engine capacity - where are you plucking these assumptions from ?

I'm saying that I believe what is commercially available today for up to L24s is of the same diameter as offered by Nissan on their JDM 2.0 and 2.4ltr engines.

For a reason unbeknownest to me, no-one is marketing an upscaled dual-pipe for engines bigger than 2.4ltre and certainly those which have been improved over and above the stock L24s from the early '70s.........unless you know of such a kit available today ?

I was speculating that perhaps for fitting/ground-clearance reasons (and also a limited JDM because the L26s and above weren't sitted as stock ?) an upscaled dual-pipe wasn't available....

But I'll ask you Alan - why isn't one available with the plethora of larger engine swaps and strokers ?

[Sean Dezart]

20 minutes ago, Jason240z said:

That’s on 3.0/3.2 ltr na engines.

What's their internal diameter pipe dimension Jason please ?

[Jason240z]

46 minutes ago, Sean Dezart said:

What's their internal diameter pipe dimension Jason please ?

I’m not sure off hand.  I’m not sure why you say ‘scaled up’ they’re just mentioning the Jdm market cars they’re for.  

 

Regsrding the US importer, that’s their own issue.

so given that they have them on one of the greatest performance IL6’s ever made, which range from 3.0 to 3.2 ltrs, you cant say they don’t work.

bar spirit garage/nissan/ fujitsubo, I’d argue others aren’t doing them as it’s harder to fit and package properly. Hence the newer fujitsubo that also offers more performance vs the older design also.  Nothing at all to do with ‘scalability’.

 

 

Edited April 3, 2018 by Jason240z

[HS30-H]

33 minutes ago, Sean Dezart said:

Nobody has said that a dual-pipe can't be scaled up in proportion to the engine capacity - where are you plucking these assumptions from ?

Your quote: "....dual pipes are better suited towards the smaller cc engines (S20 and L20) than larger".

Right there. Or am I seeing things? It only reads one way are far as I can see.

In answer to your direct question to me, I presume (betting that Nissan knew a little bit more about all this than you or I) that there are benefits in a true dual-pipe system on a straight six engine. Those benefits might well include packaging/routing, and there would - quite possibly - be a limit to that pipe dia. wise? Most of the big capacity/big power-aimed systems made and marketed in Japan go to single pipe systems, and I presume this is also packaging/routing influenced just as much as anything else. In fact, such 'big single' systems often seemed to be 'drag' biased and less to do with variable range street drivability and (pleasing) sound.

For the record, there are big pipe twin systems available in Japan, but they are mostly aimed at S20-engine C10-series Skylines. Maximum reasonable bore and stroke on S20 engines is limited to around 2400cc (you can go a little bigger, but it's marginal) so 'ideal' pipe dia on a twin pipe system for such high state of tune S20s is not going to need to be all that big anyway...  

[HS30-H]

By the way Sean, one of the clues to guide us regarding the Fujitsubo systems is their 'Legalis' name. They are a tested and licensed road legal system for the Japanese market. Most others are not, and may have to be removed when the car is tested. There are restrictions on fitment, clearance, safety and - crucially - noise. When discussing 'ideals', you have to take this into consideration for the Fujitsubo systems. 

[Sean Dezart]

44 minutes ago, HS30-H said:

Your quote: "....dual pipes are better suited towards the smaller cc engines (S20 and L20) than larger".

Right there. Or am I seeing things? It only reads one way are far as I can see.

Ok, ok - the 50mm (missed off the sentence) dual-pipes that were (from Nissan) and still are (from Fujitsubo) commercially available are better suited towards the smaller cc engines (S20, L20 and L24) than larger.

44 minutes ago, HS30-H said:

In answer to your direct question to me, I presume (betting that Nissan knew a little bit more about all this than you or I) that there are benefits in a true dual-pipe system on a straight six engine. Those benefits might well include packaging/routing, and there would - quite possibly - be a limit to that pipe dia. wise? Most of the big capacity/big power-aimed systems made and marketed in Japan go to single pipe systems, and I presume this is also packaging/routing influenced just as much as anything else. In fact, such 'big single' systems often seemed to be 'drag' biased and less to do with variable range street drivability and (pleasing) sound.

There probably are but you're saying that you don't know of them ?

An E and D-Type have twin pipe systems (admiteddly the D(Type are VERY short) but both they have ridiculously short primary pipes compared to an L-gata and both are DOHCs.

So why is it that headers and lines are so 'drag' biased ? Only motorsport competition open (read affordable) for most owners ?

44 minutes ago, HS30-H said:

For the record, there are big pipe twin systems available in Japan, but they are mostly aimed at S20-engine C10-series Skylines. Maximum reasonable bore and stroke on S20 engines is limited to around 2400cc (you can go a little bigger, but it's marginal) so 'ideal' pipe dia on a twin pipe system for such high state of tune S20s is not going to need to be all that big anyway...  

Thanks for the info - and so, again, a small cc, high revving engine...presumbly the pipe diameter was scaled up because :

a) it'll match the combustion chambers' demands

b ) it could fit under that model of car

How big is 'big' basing the sandard diameter at 50mm ?

45 minutes ago, Jason240z said:

I’m not sure off hand.  I’m not sure why you say ‘scaled up’ they’re just mentioning the Jdm market cars they’re for.  

Regsrding the US importer, that’s their own issue.

so given that they have them on one of the greatest performance IL6’s ever made, which range from 3.0 to 3.2 ltrs, you cant say they don’t work.

I think you missed the point - Alan was talking scaling up - not me.

Re importer - of course but relevant here because they were quoted AND are the N-American official importers : nice to see the extra model-specific info in there - good customer-advice.

Interestingly, the RHD Legalis image shows two seperate resonator pipes as per the Spirit Garage version whereas that listed on Whiteheads' page is of the 'H' crossover design.

Yes, they do work but you're comparing the incomparable : a modern '90s, DOHC, variable valve timing, high revving engine to a relatively lazy SOHC conceived in the mid-60s.

1 hour ago, Jason240z said:

bar spirit garage/nissan/ fujitsubo, I’d argue others aren’t doing them as it’s harder to fit and package properly. Hence the newer fujitsubo that also offers more performance vs the older design also.  Nothing at all to do with ‘scalability’.

I don't think that packaging is such an issue within the JDM which is for where all of these parts are destined. Do you believe that the new Fujitsubo offers more performance over the previous model or simply easier to fit around bigger diffs and with much better cround clearance which would (for me) be enough of an advantage in itself ?