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:-)=C2=A0=C2=A0 been there done that.=C2=A0 Even once built a mini lathe (C=
NC) to make needle profiles as desired. (sold it for a pretty penny a coupl=
e years back.)
>From playing with all that over the years, I learned enough about engine an=
d breathing dynamics to feel comfortable designing my own FI for my Spit6ht=
tp://www.teglerizer.com/triumphstuff/spit6whiteyFI/spit6_fullengine.jpg
then went a bit crazy with it all
http://www.teglerizer.com/fi/MGB_twins/index.htmlhttp://www.teglerizer.com/=
fi/MGB/index.htmlhttp://www.teglerizer.com/fi/twinbodies/twin_throttle_bodi=
es_on_a_gt6.htm
hhhmm... come to think of it.... only Liberty still has SU's!https://www.yo=
utube.com/watch?v=3Dkvs_dLi2nJE
:-)
ptegler
-----Original Message-----
From: Anthony Rhodes <spamiam@comcast.net>
To: triumphs <triumphs@autox.team.net>
Cc: trguy75 <trguy75@gmail.com>; ptegler <ptegler@verizon.net>
Sent: Wed, Oct 17, 2018 8:56 am
Subject: Re: 61 TR3A SU H6 Carb Issues
Paul,
I had not seen your SU treatise before.=C2=A0 I admit that I am as mystifie=
d you about your observed results.=C2=A0=20
There seem to be two potential effects of having the air box vs not having =
it in the carbs. You mention the slight overall vacuum it creates and you a=
llude to a change in resonance that it may create.=C2=A0 I have never exper=
ienced this problem, but I do not have much experience.=C2=A0=20
I certainly do not believe that SU carbs REQUIRE a less than atmospheric pr=
essure at the mouth of the choke.=C2=A0 But one thing this does is make the=
carb act like the choke is on all the time and it raises the fuel level in=
the jet a bit.=C2=A0=20
So step one in checking things is to verify that the fuel in the jets is co=
rrect.=C2=A0=20
It would be interesting to see the air-fuel mixture when you are experienci=
ng the stumble. It would appear to be due to a lean condition.=C2=A0=20
The idle mixture adjustment on the jet has little effect off idle. So the n=
eedle profile is most important.=C2=A0=20
When I was determining the proper needle profile for my TR7 with SU carbs, =
K&N filters and 4-1 tubular exhaust manifold, I started with the stock need=
le that was a bit too lean.=20
I made a device to measure the piston lift (therefore the needle position i=
n the jet) and used a manifold pressure sensor as well as RPM sensor and a =
tailpipe wide band oxygen sensor.=C2=A0=20
The piston lift was used simply to try to create a formula using RPM and va=
cuum to predict the piston position.=C2=A0=20
With that info I could relate needle "station" to mixture over a variety of=
real driving conditions.=C2=A0 I then hand-profiled the needles until I ha=
d a decent mixture over the full range.=C2=A0 Then I took those measurement=
s and tried to find the best match for a standard needle profile. And that =
is what I am using now.=20
I suspect that if you were to do the same thing then you would not need to =
run the original airboxes.=C2=A0 But in your case your performance is great=
as is your mileage. So why change anything.=C2=A0=20
But for other people it may be better to find the ideal mixture than to tap=
e-off large sections of their K&N filters!!!
-Tony
Sent from my 1837 Babbage Analytical Engine
> On Oct 16, 2018, at 2:00 PM, triumphs-request@autox.team.net wrote:
>=20
> Message: 6
> Date: Mon, 15 Oct 2018 23:23:23 -0400
> From: Paul Tegler <ptegler@verizon.net>
> To: Jim Henningsen <trguy75@gmail.com>, triumphs@autox.team.net
> Subject: Re: [TR] 61 TR3A SU H6 Carb Issues
> Message-ID: <e3b34234-608c-d56b-dac2-9a628a0fcc73@verizon.net>
> Content-Type: text/plain; charset=3D"utf-8"; Format=3D"flowed"
>=20
> ok....what do you mean by 'carbs aren't running smoothly'? ?
>=20
> Engine is not smooth?.. sputtering?? not running smooth while cruising?
>=20
> An old adage.... (well two actually)
> "..most carb problems are electrical..."? and "..most ignition problems=
=20
> are the carbs"
>=20
> Seriously though.... what method didyou use to balance the air flow at=20
> idle? One of those little flow meters?
> NOPE NADA STOP right there.?? Think about it...you're sealing off the=20
> air to get the bubble to rise so of course the idle changes....so the=20
> balance tube in the manifold sucks from the other carb, bypassing the=20
> fuel pull.
>=20
> I was finally convinced by an old mechanic and have learned from tuning=
=20
> more SU and ZS carbs than I care to mention.... use a 1/4" fuel line as=
=20
> a stethoscope ...one end in your ear..the other just up against the edge=
=20
> (not in) the carb throat. blocks minimal air... and believe me you can=20
> hear as little 1-2 cfm readily, but you can also hear the gurgle of the=
=20
> fuel flow!?? Years ago I actually gave away my flow gauges.
>=20
> Eons ago..I got so fed up once I bought brand new NOS SU carbs to=20
> replace mine after three rebuilds of the orig units. BUT...STILL had the=
=20
> same issue...smooth speed cruising and it ran like crap. Pull the choke=
=20
> out and it ran fine, but had to push it in at closed or low speed=20
> throttle. Spent a year+ and hundreds of messages on various LBC=20
> lists....still to no avail.? Than one day at a car show.... I saw a guy=
=20
> with an identical setup.... open big round K&Ns and a end plate but had=
=20
> his air filters nearly 3/4 closed off with duct tape.? In the end, the=20
> problem was incorrect vacuum effects ...not enough air velocity when the=
=20
> piston was mid/down as there was no restriction from the air filters.
>=20
> hhmmm.... ok...
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<div style=3D"font-size:10pt;font-family:arial,helvetica,sans-serif;color:b=
lack;"><div style=3D"font-family:arial,helvetica,sans-serif;font-size:10pt;=
color:black;">:-) been there done that. Even once built a=
mini lathe (CNC) to make needle profiles as desired. (sold it for a pretty=
penny a couple years back.)<br><br>From playing with all that over the yea=
rs, I learned enough about engine and breathing dynamics to feel comfortabl=
e designing my own FI for my Spit6</div><div style=3D"font-family:arial,hel=
vetica,sans-serif;font-size:10pt;color:black;">http://www.teglerizer.com/tr=
iumphstuff/spit6whiteyFI/spit6_fullengine.jpg<br><br>then went a bit crazy =
with it all<br>http://www.teglerizer.com/fi/MGB_twins/index.html</div><div =
style=3D"font-family:arial,helvetica,sans-serif;font-size:10pt;color:black;=
">http://www.teglerizer.com/fi/MGB/index.html</div><div style=3D"font-famil=
y:arial,helvetica,sans-serif;font-size:10pt;color:black;">http://www.tegler=
izer.com/fi/twinbodies/twin_throttle_bodies_on_a_gt6.htm<br><br>hhhmm... co=
me to think of it.... only Liberty still has SU's!</div><div style=3D"font-=
family:arial,helvetica,sans-serif;font-size:10pt;color:black;">https://www.=
youtube.com/watch?v=3Dkvs_dLi2nJE<br><br>:-)<br><br>ptegler<br><br><br><br>=
<br><br><br><br>-----Original Message-----<br>From: Anthony Rhodes <spam=
iam@comcast.net><br>To: triumphs <triumphs@autox.team.net><br>Cc: =
trguy75 <trguy75@gmail.com>; ptegler <ptegler@verizon.net><br>S=
ent: Wed, Oct 17, 2018 8:56 am<br>Subject: Re: 61 TR3A SU H6 Carb Issues<br=
><br></div><div dir=3D"ltr">Paul,<br></div><div dir=3D"ltr">I had not seen =
your SU treatise before. I admit that I am as mystified you about you=
r observed results. <br></div><div dir=3D"ltr"><br></div><div dir=3D"=
ltr">There seem to be two potential effects of having the air box vs not ha=
ving it in the carbs. You mention the slight overall vacuum it creates and =
you allude to a change in resonance that it may create. I have never =
experienced this problem, but I do not have much experience. <br></di=
v><div dir=3D"ltr"><br></div><div dir=3D"ltr">I certainly do not believe th=
at SU carbs REQUIRE a less than atmospheric pressure at the mouth of the ch=
oke. But one thing this does is make the carb act like the choke is o=
n all the time and it raises the fuel level in the jet a bit. <br></d=
iv><div dir=3D"ltr"><br></div><div dir=3D"ltr">So step one in checking thin=
gs is to verify that the fuel in the jets is correct. <br></div><div =
dir=3D"ltr"><br></div><div dir=3D"ltr">It would be interesting to see the a=
ir-fuel mixture when you are experiencing the stumble. It would appear to b=
e due to a lean condition. <br></div><div dir=3D"ltr"><br></div><div =
dir=3D"ltr">The idle mixture adjustment on the jet has little effect off id=
le. So the needle profile is most important. <br></div><div dir=3D"lt=
r"><br></div><div dir=3D"ltr">When I was determining the proper needle prof=
ile for my TR7 with SU carbs, K&N filters and 4-1 tubular exhaust manif=
old, I started with the stock needle that was a bit too lean. <br></div><di=
v dir=3D"ltr"><br></div><div dir=3D"ltr">I made a device to measure the pis=
ton lift (therefore the needle position in the jet) and used a manifold pre=
ssure sensor as well as RPM sensor and a tailpipe wide band oxygen sensor.&=
nbsp; <br></div><div dir=3D"ltr"><br></div><div dir=3D"ltr">The piston lift=
was used simply to try to create a formula using RPM and vacuum to predict=
the piston position. <br></div><div dir=3D"ltr"><br></div><div dir=
=3D"ltr">With that info I could relate needle "station" to mixture over a v=
ariety of real driving conditions. I then hand-profiled the needles u=
ntil I had a decent mixture over the full range. Then I took those me=
asurements and tried to find the best match for a standard needle profile. =
And that is what I am using now. <br></div><div dir=3D"ltr"><br></div><div =
dir=3D"ltr">I suspect that if you were to do the same thing then you would =
not need to run the original airboxes. But in your case your performa=
nce is great as is your mileage. So why change anything. <br></div><d=
iv dir=3D"ltr"><br></div><div dir=3D"ltr">But for other people it may be be=
tter to find the ideal mixture than to tape-off large sections of their K&a=
mp;N filters!!!<br></div><div dir=3D"ltr"><br></div><div dir=3D"ltr">-Tony<=
br></div><div dir=3D"ltr"><br></div><div dir=3D"ltr">Sent from my 1837 Babb=
age Analytical Engine<br></div><div dir=3D"ltr"><br></div><div dir=3D"ltr">=
> On Oct 16, 2018, at 2:00 PM, <a ymailto=3D"mailto:triumphs-request@aut=
ox.team.net" rel=3D"noopener noreferrer" href=3D"mailto:triumphs-request@au=
tox.team.net">triumphs-request@autox.team.net</a> wrote:<br></div><div dir=
=3D"ltr">> <br></div><div dir=3D"ltr">> Message: 6<br></div><div dir=
=3D"ltr">> Date: Mon, 15 Oct 2018 23:23:23 -0400<br></div><div dir=3D"lt=
r">> From: Paul Tegler <<a ymailto=3D"mailto:ptegler@verizon.net"; rel=
=3D"noopener noreferrer" href=3D"mailto:ptegler@verizon.net";>ptegler@verizo=
n.net</a>><br></div><div dir=3D"ltr">> To: Jim Henningsen <<a ymai=
lto=3D"mailto:trguy75@gmail.com"; rel=3D"noopener noreferrer" href=3D"mailto=
:trguy75@gmail.com">trguy75@gmail.com</a>>, <a ymailto=3D"mailto:triumph=
s@autox.team.net" rel=3D"noopener noreferrer" href=3D"mailto:triumphs@autox=
.team.net">triumphs@autox.team.net</a><br></div><div dir=3D"ltr">> Subje=
ct: Re: [TR] 61 TR3A SU H6 Carb Issues<br></div><div dir=3D"ltr">> Messa=
ge-ID: <<a ymailto=3D"mailto:e3b34234-608c-d56b-dac2-9a628a0fcc73@verizo=
n.net" rel=3D"noopener noreferrer" href=3D"mailto:e3b34234-608c-d56b-dac2-9=
a628a0fcc73@verizon.net">e3b34234-608c-d56b-dac2-9a628a0fcc73@verizon.net</=
a>><br></div><div dir=3D"ltr">> Content-Type: text/plain; charset=3D"=
utf-8"; Format=3D"flowed"<br></div><div dir=3D"ltr">> <br></div><div dir=
=3D"ltr">> ok....what do you mean by 'carbs aren't running smoothly'? ?<=
br></div><div dir=3D"ltr">> <br></div><div dir=3D"ltr">> Engine is no=
t smooth?.. sputtering?? not running smooth while cruising?<br></div><div d=
ir=3D"ltr">> <br></div><div dir=3D"ltr">> An old adage.... (well two =
actually)<br></div><div dir=3D"ltr">> "..most carb problems are electric=
al..."? and "..most ignition problems <br></div><div dir=3D"ltr">> are t=
he carbs"<br></div><div dir=3D"ltr">> <br></div><div dir=3D"ltr">> Se=
riously though.... what method didyou use to balance the air flow at <br></=
div><div dir=3D"ltr">> idle? One of those little flow meters?<br></div><=
div dir=3D"ltr">> NOPE NADA STOP right there.?? Think about it...you're =
sealing off the <br></div><div dir=3D"ltr">> air to get the bubble to ri=
se so of course the idle changes....so the <br></div><div dir=3D"ltr">> =
balance tube in the manifold sucks from the other carb, bypassing the <br><=
/div><div dir=3D"ltr">> fuel pull.<br></div><div dir=3D"ltr">> <br></=
div><div dir=3D"ltr">> I was finally convinced by an old mechanic and ha=
ve learned from tuning <br></div><div dir=3D"ltr">> more SU and ZS carbs=
than I care to mention.... use a 1/4" fuel line as <br></div><div dir=3D"l=
tr">> a stethoscope ...one end in your ear..the other just up against th=
e edge <br></div><div dir=3D"ltr">> (not in) the carb throat. blocks min=
imal air... and believe me you can <br></div><div dir=3D"ltr">> hear as =
little 1-2 cfm readily, but you can also hear the gurgle of the <br></div><=
div dir=3D"ltr">> fuel flow!?? Years ago I actually gave away my flow ga=
uges.<br></div><div dir=3D"ltr">> <br></div><div dir=3D"ltr">> Eons a=
go..I got so fed up once I bought brand new NOS SU carbs to <br></div><div =
dir=3D"ltr">> replace mine after three rebuilds of the orig units. BUT..=
.STILL had the <br></div><div dir=3D"ltr">> same issue...smooth speed cr=
uising and it ran like crap. Pull the choke <br></div><div dir=3D"ltr">>=
out and it ran fine, but had to push it in at closed or low speed <br></di=
v><div dir=3D"ltr">> throttle. Spent a year+ and hundreds of messages on=
various LBC <br></div><div dir=3D"ltr">> lists....still to no avail.? T=
han one day at a car show.... I saw a guy <br></div><div dir=3D"ltr">> w=
ith an identical setup.... open big round K&Ns and a end plate but had =
<br></div><div dir=3D"ltr">> his air filters nearly 3/4 closed off with =
duct tape.? In the end, the <br></div><div dir=3D"ltr">> problem was inc=
orrect vacuum effects ...not enough air velocity when the <br></div><div di=
r=3D"ltr">> piston was mid/down as there was no restriction from the air=
filters.<br></div><div dir=3D"ltr">> <br></div><div dir=3D"ltr">> hh=
mmm.... ok...<br></div></div>
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