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P. J. =E2=80=94 I=E2=80=99m off away from camshafts here, but how much =
weight can you pull off the car? Light wheels and tires can help but =
might be a ways down some peoples=E2=80=99 list for ways to reduce the =
weight of the car. Already got a lightweight flywheel you can use? =
Final drive change (or taller/lower profile tires to make an equivalent =
change) might be worthwhile to check out. I have a tiny (NSU) race =
sedan that tops out at 93mph whether I have tall tires or low-sidewall =
tires (different rpm, obviously), so its speed is drag/power limited, =
and apparently not limited by having the wrong final drive ratio =E2=80=94=
however opting for taller tires (or a lower numerical final drive =
ratio) means I=E2=80=99m not accelerating as quickly, plus the car=E2=80=99=
s center of gravity sits higher, which doesn=E2=80=99t help the =
handling.
Duncan
> On Oct 31, 2015, at 5:44 PM, McKearn McKearn <mckearn2@gmail.com> =
wrote:
>=20
> I can tell you that I already have a GT6 with a good flexible power =
band and good reliability. It lacks quickness however, due in part to =
the TR6 engine which is not highly tuned and I'm sure the gearing could =
be better (3.27 rearend-Toyota T50 trans.)( Good for the highway.) My =
old car is pretty much to the point where I don't want to do anything =
more to it so I want to move on to another project. This time I want to =
build a car that snorts . I do however need to put it on and off the =
trailer and I'm not thrilled about breaking parts with max. RPMs so I =
can't afford to go all out. I'm looking for quickness through the gears =
and good handling.=20
> P.J.=20
>=20
> On Sat, Oct 31, 2015 at 3:43 PM, Duncan Charlton =
wrote:
> Larry=E2=80=99s comments make me wonder the precise intended purpose =
of the engine mentioned by the original poster. =E2=80=9CTrack days=E2=80=
=9D might mean different things to different people. Does P. J. want a =
good flexible power band, or does he need an ultimate dyno horsepower =
figure? Does the motor have the gear set to be able to take advantage =
of an engine with very little low-end torque? How high among his =
priorities is the ability to be able to drive the car back on the =
trailer at the end of every track weekend? Lack of sponsorship and cash =
prizes mean that I must find the setup that maximizes the fun/cost =
ratio.
>=20
> Duncan
>=20
>=20
> > On Oct 31, 2015, at 1:34 PM, Larry Young <cartravel@pobox.com =
> >
> > That is an interesting article, but only speaks to one side of the =
issue. I always say that you want to pick an intake duration for an RPM =
range that you're willing and able to turn. We all know what happens to =
a stock TR4 crank which sees >6,000 on a regular basis. Some guys want =
a cam good beyond 7,000, but they are just not willing to push it that =
far. Nowadays I'm more of a street car guy, but still like to have =
power. I don't believe the choices should be to do nothing or go all =
the way to race specs. =46rom 1968 on Triumphs were severely detuned to =
pass emissions. Compression ratio and duration and hence cam overlap at =
TDC were reduced. For example, the early TR250/6 had 193 degrees =
duration (measured at 0.050), while the TR4 was about 215 and the early =
PI TR5/6 was 226. It seems crazy to rebuild a street car of this era to =
the original specs. Bumping the compression ratio by a point and =
increasing the duration to something like 210-215 will make the engine =
the way it would have been without emission restrictions. I would not =
feel guilty about polluting the planet, since most of these cars see few =
miles annually and most of the other pollution controls (e.g. ignition =
retard) probably quit working years ago.
> > - Larry
> >
> > On 10/29/2015 7:25 AM, Duncan Charlton wrote:
> >> Cam specs and static CR are interactive. This will give you a =
rundown if you are not already knowledgeable about this subject:
> >>
> >> =
http://www.crankshaftcoalition.com/wiki/Cam_and_compression_ratio_compatib=
ility =
<http://www.crankshaftcoalition.com/wiki/Cam_and_compression_ratio_compati=
bility>
> >>
> >> Duncan
> >> (Texas)
> >>
> >>
> >
> > _______________________________________________
> >
> > http://www.fot-racing.com <http://www.fot-racing.com/>
> >
> > Donate: http://www.team.net/donate.html =
<http://www.team.net/donate.html>
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> > Unsubscribe/Manage: =
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<http://autox.team.net/mailman/options/fot/duncan.charlton54@gmail.com>
> >
> >
>=20
> _______________________________________________
>=20
> http://www.fot-racing.com <http://www.fot-racing.com/>
>=20
> Donate: http://www.team.net/donate.html =
<http://www.team.net/donate.html>
> Archive: http://www.team.net/archive <http://www.team.net/archive>
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> Unsubscribe/Manage: =
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>=20
>=20
>=20
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<html><head><meta http-equiv=3D"Content-Type" content=3D"text/html =
charset=3Dutf-8"></head><body style=3D"word-wrap: break-word; =
-webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" =
class=3D"">P. J. =E2=80=94 I=E2=80=99m off away from camshafts here, but =
how much weight can you pull off the car? Light wheels and tires =
can help but might be a ways down some peoples=E2=80=99 list for ways to =
reduce the weight of the car. Already got a lightweight flywheel =
you can use? Final drive change (or taller/lower profile tires to =
make an equivalent change) might be worthwhile to check out. I =
have a tiny (NSU) race sedan that tops out at 93mph whether I have tall =
tires or low-sidewall tires (different rpm, obviously), so its speed is =
drag/power limited, and apparently not limited by having the wrong final =
drive ratio =E2=80=94 however opting for taller tires (or a lower =
numerical final drive ratio) means I=E2=80=99m not accelerating as =
quickly, plus the car=E2=80=99s center of gravity sits higher, which =
doesn=E2=80=99t help the handling.<div class=3D""><div class=3D""><br =
class=3D""></div><div class=3D"">Duncan</div><div class=3D""><br =
class=3D""></div><div class=3D""><br class=3D""><div><blockquote =
type=3D"cite" class=3D""><div class=3D"">On Oct 31, 2015, at 5:44 PM, =
McKearn McKearn <<a href=3D"mailto:mckearn2@gmail.com"; =
class=3D"">mckearn2@gmail.com</a>> wrote:</div><br =
class=3D"Apple-interchange-newline"><div class=3D""><div dir=3D"ltr" =
class=3D""><div class=3D"">I can tell you that I already have a GT6 with =
a good flexible power band and good reliability. It lacks =
quickness however, due in part to the TR6 engine which is =
not highly tuned and I'm sure the gearing could be better =
(3.27 rearend-Toyota T50 trans.)( Good for the highway.) My old car =
is pretty much to the point where I don't want to do anything more =
to it so I want to move on to another project. This =
time I want to build a car that snorts . I do however need to put =
it on and off the trailer and I'm not thrilled about breaking parts with =
max. RPMs so I can't afford to go all out. I'm looking for =
quickness through the gears and good handling. </div><div =
class=3D""> &nb=
sp;  =
; &=
nbsp; &nb=
sp; =
P.J. </div></div><div class=3D"gmail_extra"><br class=3D""><div =
class=3D"gmail_quote">On Sat, Oct 31, 2015 at 3:43 PM, Duncan Charlton =
<span dir=3D"ltr" class=3D""><<a =
href=3D"mailto:duncan.charlton54@gmail.com"; target=3D"_blank" =
class=3D"">duncan.charlton54@gmail.com</a>></span> wrote:<br =
class=3D""><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 =
.8ex;border-left:1px #ccc solid;padding-left:1ex">Larry=E2=80=99s =
comments make me wonder the precise intended purpose of the engine =
mentioned by the original poster. =E2=80=9CTrack days=E2=80=9D =
might mean different things to different people. Does P. J. want a =
good flexible power band, or does he need an ultimate dyno horsepower =
figure? Does the motor have the gear set to be able to take =
advantage of an engine with very little low-end torque? How high among =
his priorities is the ability to be able to drive the car back on the =
trailer at the end of every track weekend? Lack of sponsorship and =
cash prizes mean that I must find the setup that maximizes the fun/cost =
ratio.<br class=3D"">
<br class=3D"">
Duncan<br class=3D"">
<br class=3D"">
<br class=3D"">
> On Oct 31, 2015, at 1:34 PM, Larry Young <<a =
href=3D"mailto:cartravel@pobox.com"; class=3D"">cartravel@pobox.com</a>>=
wrote:<br class=3D"">
><br class=3D"">
> That is an interesting article, but only speaks to one side of the =
issue. I always say that you want to pick an intake duration for =
an RPM range that you're willing and able to turn. We all know what =
happens to a stock TR4 crank which sees >6,000 on a regular =
basis. Some guys want a cam good beyond 7,000, but they are just =
not willing to push it that far. Nowadays I'm more of a street car guy, =
but still like to have power. I don't believe the choices should =
be to do nothing or go all the way to race specs. =46rom 1968 on =
Triumphs were severely detuned to pass emissions. Compression =
ratio and duration and hence cam overlap at TDC were reduced. For =
example, the early TR250/6 had 193 degrees duration (measured at 0.050), =
while the TR4 was about 215 and the early PI TR5/6 was 226. It seems =
crazy to rebuild a street car of this era to the original specs. =
Bumping the compression ratio by a point and increasing the duration to =
something like 210-215 will make the engine the way it would have been =
without emission restrictions. I would not feel guilty about =
polluting the planet, since most of these cars see few miles annually =
and most of the other pollution controls (e.g. ignition retard) probably =
quit working years ago.<br class=3D"">
> - Larry<br class=3D"">
><br class=3D"">
> On 10/29/2015 7:25 AM, Duncan Charlton wrote:<br class=3D"">
>> Cam specs and static CR are interactive. This will give =
you a rundown if you are not already knowledgeable about this =
subject:<br class=3D"">
>><br class=3D"">
>> <a =
href=3D"http://www.crankshaftcoalition.com/wiki/Cam_and_compression_ratio_=
compatibility" target=3D"_blank" rel=3D"noreferrer" =
class=3D"">http://www.crankshaftcoalition.com/wiki/Cam_and_compression_rat=
io_compatibility</a><br class=3D"">
>><br class=3D"">
>> Duncan<br class=3D"">
>> (Texas)<br class=3D"">
>><br class=3D"">
>><br class=3D"">
><br class=3D"">
> _______________________________________________<br class=3D"">
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class=3D"">fot@autox.team.net</a><br class=3D"">
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rel=3D"noreferrer" class=3D"">http://www.fot-racing.com</a><br class=3D"">=
><br class=3D"">
> Donate: <a href=3D"http://www.team.net/donate.html"; target=3D"_blank"=
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