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Moggie

My Experience With Triple Webers

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I Thought id share my experince with going to tripple webbers on my 260z,because alot of people said not to go tripple webbers because of drivability and fuel ecconomy on the street. After doing my engine rebuild (2.7L 9.8:1comp cam ect) After the rebuild i could not get it torun right on the twin british SUs so i got them rebuilt, got trumpets for them and new k&n filters. $400 later they were better but ran too lean with the new setup. I looked into new needle and regrinding the ones that were in there but then decided to bite the bullet and triple Webers because I was sick of messing with the SUs.

I bought brand new 40 dcoe 151s with redline manifold and linkage. At first it ran rough so i advanced the timing and bingo it was sweet straight out of the box. With the standard jets that were in the carbs the car drove beautifully with only a slight hesitation as you stab the accelerator. The mixtures are a little rich around 12.0-12.5 under load and 13.0 when cruising.

I have put in larger idle jets and it fixed the hesitation as you stab the accelerator. Im still yet to fit diffent main jets to lean the mixture out a little just because it is driving so well at the moment, every spare moment I get im driving the car haha

IMO the webers are way better than the SUs even when they were running right on the old engine.

With the webers the car drives better when cold with no choke needed, has instant theottle responce, more torue down low, way more top end power, fuel economy is about the same if not better and did I mention the sound!

All of the cons that I heard with tripple webers I have not experienced. These carbs drive beautifuly on the street and have not let me down in any way yet.

Any way just me 2c.

post-104507-0-20315700-1452258769_thumb.jpeg

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Why-Oh-Why did you go with 40's? :(
You are strangling the engine with those little carbs.

45's are a FAR better thing on a decent L6...

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Hi Moggie,

I'd be keen to hear what economy you are getting. I've got triple 45's on a stock L28, got 11l/100 k on a long road trip. But round town using 17.5. Just interested to hear as webers often get a bad wrap in this regard, but with such adjustabilty you'd think a compromise would be possible.

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Hi Moggie,

I'd be keen to hear what economy you are getting. I've got triple 45's on a stock L28, got 11l/100 k on a long road trip. But round town using 17.5. Just interested to hear as webers often get a bad wrap in this regard, but with such adjustabilty you'd think a compromise would be possible.

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That is a sweet looking engine bay you have Moggie. I also found 40's better for the street, but lacking just a bit for the track on long straights . They say the sound of a well tuned V8 is hard to beat . but the sound a set of triples make at 6500 in third coming on to the main straight at Lakeside and changing into fourth with it flat to the floor has got to be up there with any V8.  

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My experience with SUs on my 72 240z is not that great. I have great low down torque but she is definitely leaning out at higher RPM. I have decided to do something with my Triple Mikuni 44s and will likely put them on my 72 240z. The only reason I haven't yet is due to lack of a good air box for Triples.

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I went the 40s because all the people I spoke to said not to go 45s for a street car. Its only a mild cam so i decided against the 45s ot not all about peak power its the area under the power curve ;) and this pulls well from 2500rpm throght to 6000rpm. Im really happy with the 40s thus far I will get it on the dyno next week and see what she is putting out. My wife has an r34 skyline with an ls2 putting out 290 rwkw so thats the car that normally hits the track, when the wife lets me haha. But if I decide to track this z and I find the 40s arent flowing enough il just put some 36mm chokes in.

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Yes definitely need an airbox because i know the rear carb will be running leaner because the air will be hotter. Im going to tig one up out of alluminium when i get a chance.

 

My experience with SUs on my 72 240z is not that great. I have great low down torque but she is definitely leaning out at higher RPM. I have decided to do something with my Triple Mikuni 44s and will likely put them on my 72 240z. The only reason I haven't yet is due to lack of a good air box for Triples.

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I got just under 500km to the last tank of 46L to fill up and that was highway driving street driving mostly spirited because iv been loving how well it goes now compared to the SUs

 

Hi Moggie,

I'd be keen to hear what economy you are getting. I've got triple 45's on a stock L28, got 11l/100 k on a long road trip. But round town using 17.5. Just interested to hear as webers often get a bad wrap in this regard, but with such adjustabilty you'd think a compromise would be possible.

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The talk f "dont go for 45's" etc,,,,

Nissan fitted 44's on the 2litre, and 44's on the 2.4 litre, seemed to work pretty fine.

They even fitted 44's on a four cylinder, as stock.

 

It comes down to the knowledge and capability f the person setting the carbs up, and getting them to run correctly.

 

Too many "mechanics" out there who take on such work, on the hope they get it clse.

The car owner is left with the result,,,

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Great that you're happy with the set up. It's funny how all these people say triples are hard work. They've also never had triples!

I've had both 40's and 44's.

I'd always advise to go 44's or 45's. Street car or not.

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My experience with SUs on my 72 240z is not that great. I have great low down torque but she is definitely leaning out at higher RPM. I have decided to do something with my Triple Mikuni 44s and will likely put them on my 72 240z. The only reason I haven't yet is due to lack of a good air box for Triples.

I've always thought air box is the best way to go, but then you see the engine in Green Hornet and it doesn't have an air box.

Good heat shielding and improving air to the carbs will do the job if you can't find a decent air box

 

post-104002-0-10594100-1452372193_thumb.jpg

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The problem with the ITG filter is where do you put the oil breather hose? I guess you require an oil catch can then?

 

Most S30z's in Japan appear to run Triples. Not many on the stock SU's. My guess is that conventional wisdom there is that Triples are the way to go.

 

Especially with a warm L-series. Nissan was looking at offering the Triples as standard fitment to the 240z but the pin was pulled on the idea. I guess bean counters and emission rules are partly to blame.

 

Would have been great if they did it like on the Fairlady Z432.

 

Nissan or Prince offered to Skyline GTBs here in the 60s with Triple Carbs and LSD + large fuel tank as standard.

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Stick a little filter on the rocker cover? I don't see this as a big deal. My engine doesnt even have a crankcase vent anymore.

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Stick a little filter on the rocker cover? I don't see this as a big deal. My engine doesnt even have a crankcase vent anymore.

 

I'm sure there was a discussion about this previously in 1 of your threads, where do you vent it?

 

Just read this myself.

http://oppositelock.kinja.com/ditch-that-pcv-system-before-it-is-too-late-1634156554

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Iv just got both my breathers running to a catch can filled with steel wool and a little filter on it. Or if you want to keep a simular setup as if you were running a pcv. Weld a tube in at 45deg in your headers collector and connect the crank case breather to that. That will draw air in through the top breather and out throught the cranks case allong with all the crank case gases. The hot exhaust will burn the oil vapor aswell.

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I'm sure there was a discussion about this previously in 1 of your threads, where do you vent it?

 

Just read this myself.

http://oppositelock.kinja.com/ditch-that-pcv-system-before-it-is-too-late-1634156554

 

Basically i talked to PMC about it and my crank swings out so far there isn't room to run it. He said "don't worry about it, it's fine" so i didn't. The pressurised air can still come up the timing chain gallery and vent out through the rocker cover, which I will run to a catch can for track purposes, which ultimately will terminate with a filter on the top. So really same same as running it on the rocker cover.

 

I'm currently fitting the ITG 100 to my stroker motor too. I'll detail the install in my build thread. Looks so much better than those crappy uni filter socks i have currently.
Edited by d3c0y

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On 1/9/2016 at 7:57 AM, Lurch said:

Why-Oh-Why did you go with 40's? :(
You are strangling the engine with those little carbs.

45's are a FAR better thing on a decent L6...

I haven't installed mine yet or finished my build but I am so glad I took your advice and bought 45's.  

 

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On 1/11/2016 at 9:54 AM, d3c0y said:

The pressurised air can still come up the timing chain gallery and vent out through the rocker cover,

Yep, Les Collins "deleted" the crankcase vent on my L28 saying the above ^^^^

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Posted (edited)
13 hours ago, Zedhead said:

I haven't installed mine yet or finished my build but I am so glad I took your advice and bought 45's.  

 

Yea, absolutely. I've run 40mm webers, then a 4 barrel and now SU's. On an L26. 

The webers had awesome bottom end torque, but would literally run out of breath above 5000rpm.Mine were 152s with the default choke, 32mm??. Maybe a bigger choke would have helped. But it struggled to get to 50kmh in first. By comparison the SU's breeze it in. 

 

Rob 

Edited by RAP260

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