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Cruising RPM's

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B0b3156 Bob Carey
Carver, MA, USA   USA
Hello I am a new member.I just bought my first Spitfire 1980.So many questions.What would a safe rpm level you can maintain in 4th gear?

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skyking1231 Avatar
skyking1231 Silver Member Frank Strobel
Mt. Sinai, NY, USA   USA
1975 Triumph Spitfire 1500 "Lil' Rose"
Here is a good chart under gearbox http://www.triumphspitfire.com/Size.html

With stock size tires.... 18mph/1000rpm in 4th gear...with 389 diff. So 3000 rpm should be appox 54mph (well within the safe range of motor).
1500 can do 4000 all day long provided engin is running sound (oil, cooling etc). Some run higher....however i am a big pu$$y, and keep my rpms around 3000-3500rpm. I do have overdrive. But even accelerating ...i keep it under 3500.

B0b3156 Bob Carey
Carver, MA, USA   USA
Thank you

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clshore Carter Shore
Beverly Hills, Florida, USA   USA
A 1500 does not tolerate revs well.
The longer stroke (3.44"winking smiley, combined with the heavy conrods (720 g EACH), conspire to place unreasonable stress on
the already marginal conrod bearings above 5,000 RPM.
OTOH, the larger displacement (extra 197 cc) and longer stroke yield better low and midrange torque.

Realizing this, and catering to the EPA emissions regulations,
Triumph fitted pieces that favor low and mid range RPM, to the detriment of higher RPM:
A single carb, an intake manifold with smaller runners, a cam with timing less overlap and duration, and very conservative ignition timing.

Many folks have fitted the 3.27 or 3.63 diff gears, or OverDrive, or 5 speed transmission (Ford T9, Toyota T-50).

The 1500 can generate enough torque to give pleasant lower RPM cruising, and acceptable performance in lower gears.
Many folks will say it's a bad combination, but many of the folks who have actually done it, seem pleased.

The factory even offered this 1500 & 3.27 combination is Swiss export Spitfires.

Wolfcreek Steve Steve P
Central, Wisconsin, USA   USA
I have a 3.89 diff and no OD, I have run 80-85 for several hours at a time without catastrophe.

Brad.Cogan Avatar
Brad.Cogan Bradley Cogan
RAF Cosford, Shropshire, UK   GBR
1977 Triumph Spitfire 1500 "Wray"
2007 Fiat Grande Punto "Pepper"
I tend to drove at around 65mph for 3 hours at a time and I've had no issues. I've got smaller tyres too so at that speed it's at about 3500-4000rpm.



Brad Cogan

1977 Triumph Spitfire 1500 'Wray'
2007 Fiat Grande Punto Active 1.2 'Pepper'

TheFlash300 Avatar
TheFlash300 Dave Gutknecht
Rochester Hills, Michigan, USA   USA
1979 Triumph Spitfire 1500 "Lil Spit"
I have '79 1500 with the 3.89 and no OD. I have done many hours on the interstate above 70mph (~4200rpm).
In general I keep in under 5000rpm when driving on public roads. I have gone up to 5600rpm in 3rd gear on limited short occasions on the track.

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79bluespit Avatar
79bluespit Rick Lazio
Burlington, ON, Canada   CAN
i guess the question asked probably refers to engine durability... and what your top end speed will be without causing engine destruction. decades ago in my teens i had a spitfire 1500 where i knew nothing about the engines weaknesses. i abused that engine like no tomorrow. donuts, high revving on the highway, snap acceleration from a red, a temp sensor constantly in the hot... even then i never trusted the gauge and thought if it's not boiling over and there's fluid in there.... it has to be fine.... turned out it was fine. and in the end... the engine and trans still went fine after 10 months of complete and utter abuse of a teen. only the police stopped me back then for a roadside inspection and took the car off the road. body was rusty. but it was trusty.

Tonyfixit Avatar
Tonyfixit Tony M
Duncan, British Columbia, Canada   CAN
I find crusing above 70 mph tiresom, more so if you do not have high gearing or O/D.

The chances are you will want to quit or slow down before your engine does.

No, the 1500's are not so suitable for higher rpm's, and the state tune of the North American versions does not encourage this. But, IMHO they are not that frail. These engines and cars have survived 40 years! they were inexpensive cars, and likely 'got some stick' for a good portion of their life.

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Doug in Vegas Avatar
Doug in Vegas Douglas D
Las Vegas, Nevada, USA   USA
In reply to # 1496251 by clshore A 1500 does not tolerate revs well.

So the owners have to.

DerbyRam54 Neville Wardle
Branford, Connecticut, USA   USA
I agree with Tony M, driving at higher speeds can become very tiring. It isn't just the noise and vibration it's also the constant buffeting you experience. At least in my case the driver would probably give up way before the engine!

Frankly driving at any speed in the kind of traffic we get on the interstates in Connecticut is no fun at all because you are constantly surrounding by much bigger vehicles (just about any vehicle is bigger than a Spitfire) and the noise of the traffic is more of an issue than any noise the Spitfire makes. At night the experience is just horrible in the extreme.

So in some respects the question of RPM limits no longer applies, most of my driving takes place on quieter roads, generally always on the lookout for those byways that would make for a good club tour. Maybe it's an age thing, I want some pleasure and relaxation when I take the Spitfire out.

B0b3156 Bob Carey
Carver, MA, USA   USA
Thanks everybody for your response.I am new to spitfires.Its not so much about going fast.It whines some much I didn't want to blow it upLOL.I feel better now.Thanks again

colodad Avatar
colodad Silver Member Calvin Williams
Grand Junction, Colorado, USA   USA
In reply to # 1496397 by TheFlash300 I have '79 1500 with the 3.89 and no OD. I have done many hours on the interstate above 70mph (~4200rpm).
In general I keep in under 5000rpm when driving on public roads. I have gone up to 5600rpm in 3rd gear on limited short occasions on the track.

up tp 5600rpm in 3rd. in 4th that would be (18 X 5.6k rpm =) 100.8mph
you could be a flash..

TheFlash300 Avatar
TheFlash300 Dave Gutknecht
Rochester Hills, Michigan, USA   USA
1979 Triumph Spitfire 1500 "Lil Spit"
I have never gone over 90 in the Spitfire, need too much distance to achieve speeds...and traffic.
In 5600 in 3rd gear is around 67mph and can be achieved in much shorter distances on the track. The biggest thing for me when on the track is deciding what gear to be in for a given segment and this has lead me to hold 3rd gear longer, rather than up shifting to 4th and then shortly thereafter down shifting for a turn.

In reply to # 1496671 by colodad
In reply to # 1496397 by TheFlash300 I have '79 1500 with the 3.89 and no OD. I have done many hours on the interstate above 70mph (~4200rpm).
In general I keep in under 5000rpm when driving on public roads. I have gone up to 5600rpm in 3rd gear on limited short occasions on the track.

up tp 5600rpm in 3rd. in 4th that would be (18 X 5.6k rpm =) 100.8mph
you could be a flash..

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