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Triple SU manifold set up.


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Hi there, 

Has anyone fitted a triple SU manifold to a UK spec car?  As far as I'm aware these manifolds are made in America and just bolt on to their TR250/ TR6 models but over here it fouls the steering column.  I have thought about making up a rather large alloy spacer so the the third carb can clear the column but that will increase the length of the inlet tract and the top of carb might also foul the bonnet. 

Any suggestions welcomed. 

hoges. 

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Paul,

As you will know, a triple SU set-up was used on Series 1 E-types.    I'm surprised that you don't also know that this is notoriously difficult to tune, due to the unequal impulse intervals on the rear and front carbs, while the central does have equal intervals.   The same would apply to 3 Mikunis, while six Mikunis has been tried but proved to be just as difficult, with six chokes and six throttles to coordinate! 

John  

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1 minute ago, john.r.davies said:

Paul,

As you will know, a triple SU set-up was used on Series 1 E-types.    I'm surprised that you don't also know that this is notoriously difficult to tune, due to the unequal impulse intervals on the rear and front carbs, while the central does have equal intervals.  

John  

Never had any problems tuning Etypes/XK150s/Mk10 with triple SU carbs.

Stuart.

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I have to say that I never had any problems tuning E types when I was an apprentice on jags either.  In fact its because 3 carbs are better than 2 on a 6 pot that I wanted to fit then to my Dove.  I'm not sure about changing the float chambers but its an idea i will look into.  As for the Mikuni idea, lets not go there! What surprises me is how a well known   TR company could sell them without telling me they wouldn't fit!  

hoges. 

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I have triple SU’s on my 6 cyl TR4

they seem to fit fine, though would need the "dented" wheel arch to clear the air filters.

I believe I have 1 left hand and 2 right hand carbs.

many people say they cannot work with with the triumph 6 but mine has managed to develop 179bhp, so cannot be that difficult to set up...

1895CC6C-2EE1-430A-B691-B8D556B3BAC3.jpeg

BF537F7C-39A9-44F0-87E1-3AF042B305C4.jpeg

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16 hours ago, DRD said:

Thanks for that info but in this case its for a triumph tr6 motorcycle!  Not quite what I had in mind.  Cheers. 

hoges. 

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14 minutes ago, BlueTR3A-5EKT said:

Why not use 3 HIF6 or HIF44 carbs instead?

Cheers

Peter W

image.thumb.png.0e689b3c287f72fd8e4c47621984bc6c.png

Float chamber fouls on rear carb, with HS6 you can swap sides to create clearance.

Stuart.

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Reg Bowler has a set fitted to his 6.

However he machined the manifolds out of billet aluminium himself.

Not convinced it is a great performance mod compared to Lucas Pi or Webers. These give a choke to each cylinder which overcomes the firing order issue mentioned earlier.

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On 11/6/2020 at 12:04 PM, Paul Hogan said:

Hi there, 

Has anyone fitted a triple SU manifold to a UK spec car?  As far as I'm aware these manifolds are made in America and just bolt on to their TR250/ TR6 models but over here it fouls the steering column.  I have thought about making up a rather large alloy spacer so the the third carb can clear the column but that will increase the length of the inlet tract and the top of carb might also foul the bonnet. 

Any suggestions welcomed. 

hoges. 

Hi Hoges,

Have you done a trial fit to your car to see if it does foul the steering column? My view would be to go for DCOE's as this method is well tried and tested! With the freight and duty +vat from the USA it is not going to be a cheap exercise for the manifold and any other parts required?

Bruce.

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Hi Bruce, Pete,   I already have the manifold and carbs so going down the weber route is a no no for me.  However, looking at the pics people have posted I will see if either a spacer can be fitted or change the float chambers 

hoges. 

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23 minutes ago, Paul Hogan said:

Hi Bruce, Pete,   I already have the manifold and carbs so going down the weber route is a no no for me.  However, looking at the pics people have posted I will see if either a spacer can be fitted or change the float chambers 

hoges. 

Float chamber change is easiest and doesnt upset intake length.

Stuart.

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3 hours ago, stuart said:

Float chamber change is easiest and doesnt upset intake length.

Stuart.

Hi Stuart,

How much increase in performance do you get with 3 SU's v 2 SU's? Is the Webber route far better value for money?

Bruce.

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2 hours ago, astontr6 said:

Hi Stuart,

How much increase in performance do you get with 3 SU's v 2 SU's? Is the Webber route far better value for money?

Bruce.

Bit subjective really, would depend on what else is done to the engine, Triple Webers would probably get more power if headwork and cam was done to suit but SU`s would be easier to tune and would come a very close second. Webers would be dearer in sheer purchase price I suspect. With the right cam and head work twin SU`s do develop good power too.It all depends on what your going to do with the car.

Stuart.

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