HS4 SU carb inlet diameter?

[eeeaooo]

I've got a pair of Japanese SU HS4's (38mm/1.5") made by Hitachi (made for old Datsuns), of which some parts are compatible with the British SU's. I'd like to get a pair of velocity stacks/air horns for them, but I don't know if the inlet diameter matches up. The Hitachi SU's inlet diameter measures 35.8 mm....not to be confused with the butterfly or throat diameter. Can anyone tell me the INLET diameter of the British HS4 SU? This would also correspond to the velocity stack final diameter. -Thanks

 

[Nunyas]

*IF* I'm not mistaken the British SU HS4 should be a 1.5" design making it compatible with your Nippon constructed piece.

 

[DrEntropy]

BRB.... I'll check.

Measures 1.384". And lest you think me a Philistine:

HTH!!!

 

[eeeaooo]

I know that K/N filters mount the same, but the filter housings aren't made to close tolerances anyway. The velocity stack should be fairly precise (I would think). By the way, if anyone is interested, I HIGHLY recommend adding a bung in your exhaust just below the manifold/header flange, so you can mount an O2 sensor, make up a wiring harness, and add a digital air/fuel gauge. Before I got the gauge I could tune the SU pair to within 1/8 of a turn if I'm lucky. Now I can tune them to within about 10 degrees of a turn. My gas mileage has gone way up, too!

 

[DrEntropy]

...and ~yes~ that's my kitchen countertop that stuff is on...

 

[kennypinkerton]

Hey doc is that a toaster oven, or a Ronco setitandforgetit thingy?

 

[Nunyas]

huh.... a "high tech" method to get the proper tune... who'd a thought... /ubbthreads/images/graemlins/smile.gif

 

[eeeaooo]

Thanks Dr. Entropy! That converts to 35.154mm. One question though....did you measure using the calipers with points on the ends, or cylinders? If you measured with cylinders, then the actual diameter is probably a hair bigger since there's a gap between the square-edged caliper cylinder and the round wall that's not acounted for...are the cylinders on your calipers about 1/4" dia? ...because that would work perfectly dimansionally. Yippie! I can finally get air horns!!!

 

[DrEntropy]

HUH?? I used the pin gauge and the mic's inna shot. NO calipers involved... The deviation would be th' FUZZ of corrosion in the carb bore: they've been BURIED inna shed for a few years. I had to risk life and limb for this data on a timely basis and THIS is the thanks I get?!?!? /ubbthreads/images/graemlins/devilgrin.gif /ubbthreads/images/graemlins/jester.gif /ubbthreads/images/graemlins/devilgrin.gif /ubbthreads/images/graemlins/jester.gif /ubbthreads/images/graemlins/thirsty.gif


/ubbthreads/images/graemlins/cheers.gif

 

[DrEntropy]

...It's a toaster oven, Kenny.

/ubbthreads/images/graemlins/grin.gif

 

[eeeaooo]

Thanks!

I've got some extra arms and two left legs laying around in my shed if you wnt them. Just don't ask anything about them.

 

[DrEntropy]

"Anonymous donor" tags?

...I'll have 'em.

"...OI!! Wha's wid da LIMP?"

/ubbthreads/images/graemlins/grin.gif

 

[Bugeye58]

Hey Doc! Where can I get one of those nifty "C" clamps shown in the picture? The one with the numbers on it.
Jeff

 

[kennypinkerton]

hehehehehehe

 

[DrEntropy]

Them's th' new ~calibrated~ C-clamps, Jeff.

I gotta find and post an Alfa Romeo "Factory Bulletin"....

"New rules for employees:
1) The practice of using micrometers as C-clamps will cease immediately.

2) Duelling with forklifts is now STRICTLY prohibited."


Can't remember the rest but I'll dig that out.

 

[Nunyas]

[ QUOTE ]
2) Duelling with forklifts is now STRICTLY prohibited."

[/ QUOTE ]

ROFL!!! /ubbthreads/images/graemlins/lol.gif

that reminds me, I had a duel with a fork-lift once, just me and the lift. I lost with a broken foot, 21 stitches, and four 12 inch pins sticking out the end of said foot... /ubbthreads/images/graemlins/eek.gif not a very fun time.