S&S Manifold Length Calculator
Sine, Cosine, Hike!
We know you were day dreaming about sex when the triangles were floating about the blackboard, or for those of you who were already warped, you were doodling motorcycles while the teacher droned on about sines, cosines, tangents. Now all these years later when you finally got the money to build your dream bike by ripping off some other poor fool in the stock market, all you can do is thumb through catalogs hoping to find the right manifold for your V-Twin.
Points in Two Dimensional Space
Well,
you can use trig for all sorts of useful pursuits...In this case trying
to figure out what TC88 or EVO S&S manifold to order for your
bored, stroked and milled big twin. For our RSR Closed Loop Fuel Injection
system (discontinued in 2018) we used modify S&S inlet manifolds for either two or four
injector systems and heliarced on a new billet o-ring flange for our 56mm
(2 3/16") throttle body.
Above picture is an efi Sportster manifold we did 25 years ago.
We would order S&S Super D large throat
manifolds using this calculator and then set them up for turbo or
normally aspirated engines. All 113/120/135 ORCA
Motors started out with SA inlet castings that we machine and
reconfigure. S&S subsequently sort of left the Special Application
business.
Special Application Heads
Big valve S&S Special Application heads like we used in our 113/126/132/139 ORCA Motors have raised ports which effectively raises the inlet casting. If you are using regular S&S Super Stock cylinder heads the port is not raised. We use special order S&S 16-3619 manifolds that we custom ordered for bore size and specify the length with this calculator.
S&S
SA/B1 and S&S SA/B2 / B3(T143) heads are different and require different
manifolds. Besides changes in valve size they have different bolt
patterns and the ports are different. You can order B2
heads for EVO style single cam engines. We used B2 heads on the 139
ORCA and our 126 SA B2 Road Road.. Above is a manifold design for our Turbo Orca FXR.
Roll the Dice
Like the man always says...check it twice and check it once again. S&S has had a lot of trouble with people ordering the wrong manifold so they've changed their policies and the part numbers now reflect a specific inch dimension. S&S sells fixtures that you use dial calipers to determine the manifold number to order. You assemble the engine, you buy the fixture, you measure and you order. It's yours to keep.
A stock TC88 manifold is a 410 which equates to 4.100" between some point in space between your inlet ports. All this is supposed to end up with you having a manifold with .015" clearance on each head or a total of .030" to allow for expansion.
S&S makes literally hundreds of combinations as they have different heads, carburetors etc to deal with. 50 years of history to keep track of.
We use this calculator ourselves but use it at your own risk. They make nice paperweights. The S&S SA/B1 manifold pictured below was for a 113" Fuel Injected Turbo. S&S List price before we started our machining is $259.85 OUCH! We're on the wrong side of the counter!
Points of Confusion
When
you order a manifold S&S will ask you to call out a center to
center dimension of the cylinder heads inlet ports which is their designated size. At one time you could call out the
short distance between the edges of the inlet port. There is a chance
they will machine the manifold and use this number...not the center of the inlet ports.
The actual final machined manifold will install .015"
off of each inlet port surface so the actual center to cener of the
manifold will be .021" larger than tghe inlet port center line
Here we are measuring the
short side of a Super D manifold we modified for our RSR EFI System.
This particular motor had B1 inlet ports modified to 1.875".
Definitions:
Inlet Manifold Length/Number Calculator: S&S Big Twin TC/EVO |
S&S EVO and Twin Cam Manifold Numbers
Engine Application
|
Old Manifold Size Number
|
New Manifold Size Number
|
Stock Height V2 XL 883, 1100, 1200, 79" |
0
|
341
|
91" Sportster |
|
343
|
79" Retro Big Twin |
1
|
355
|
100" Sportster |
1+
|
357
|
100" Retro Big Twin |
2-
|
361
|
89" Sportster |
3
|
374
|
100" V2 Big Twin |
5++
|
387
|
88" & 100" V2 Big Twin |
6
|
397
|
111" Super Sidewinder Plus |
|
398
|
100" Twin Cam |
|
405
|
93" & 113" V2 Big Twin |
7
|
406
|
117" Super Sidewinder Plus |
|
408
|
Stock Height V2 Big Twin & Twin Cam |
8
|
410
|
107" Twin Cam |
|
414
|
98" Big Twin |
9
|
416
|
124" SSW+ & Twin Cam |
|
417
|
103" BT & Sportster V2 |
12
|
426
|
116" Twin Cam |
|
428
|
139" ORCA V2 (2C heads on V2 SA case) |
418
|