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Triumph TR6 - Carb conversion (yet again)

I have a 1976 TR6 with most of the Kastner-recommended performance tweaks to the engine: HR270/2 cam, 9.37:1 compression ratio, competition valve job,40Kvolt coil, balanced crankshaft and connecting rods, Pertronix ignition, ported intake and exhaust. Great car, but for the ZS carbs. Both have been rebuilt, but the rear one has never been right. Instead of getting a new /rebuilt ZS, I am considering taking advantage of the modifications already done and trying to make it go faster! The archives here reveal mixed opinions about Weber 40 DCOE's. BPNW and both discouraged triple webers for daily driving when asked. Quote "town driving with a lot of traffic will be frustrating" "if you rejet for daily driving, there would be no advantage over new strombergs". My mechanic is more than happy to put them on, feels they are much more reliable than ZS. Question: Do you think he is looking at a steady source of income, and not MY best interests? ;) What makes DCOE's frustrating to drive in traffic? Is the problem in setting them up correctly or keeping them set up correctly? and are they typically trouble-free once dialed in? How do they do with elevation changes? How hard are they to convert from Whoo-Hoo performance to easy drivability and back? Is increased performance AND reliability an impossible combination?
Karl Prager

Karl, Sounds like an interesting setup. My 74 has 1 1/2" SU's or HS4's. The car runs very well with little or no carb maintenance. I plan to go to 1 3/4" SU's or HS6's in the spring. Perhaps this would be an option for you. The change from ZS is from iffy to reliable. My info suggests that the SU is a better all 'round carb, and that the Webbers have marginally better performance at higher rpms. The price for a good set of used HS6's varies, but compared to the Webbers, there will be change left for other goodies. SC

Talk with other TR owners who have converted to Webers. Ask them if they ever went through the Rocky Mountains. Webers have jets for one altitude and they are AWFUL in the mountains. You would have to take them apart and change jets about 3 times each way.

When I went to VTR in Colorado (2424 miles one-way), I leaned up the mixture in Loveland, Colorado (5000 feet)on the twin SU's that came with my TR3A by 1/2 a turn and the car ran without a problem all the way up Estes Pass (12,090 feet) then all around Breckenridge (9800 feet) for a week and twice up to Hoosier Pass (11,542 feet). When I got to Boulder on the way home, I richened up the SU's by 2 flats on the boton hex nut adjuster (easily accessible) which is where they should have been in the first place.

You know about the "KISS" principle. - "Keep It Simple S....." !!!

Don Elliott, 1958 TR3A
Don Elliott

I agee with your mechanic and Don. Normally I would recomend the Webbers, but if you don't do your own work on the car (changing jets,e-tubes,chokes), I wouldn't for you. You will have to change them often for elevation changes.
Mike Munson

Thank you all so much for your opinions. Skinners Union it is, based on your comments. I will confirm Don's experiences with Rocky Mountain Triumph Club members, most of whom live in the Denver area and make frequent forays into the mtns. Over here on the Western Slope,at the edge of the desert, my favorite drives have 3000 to 5000 ft elevation gain; just outside of town. You Canadians may not want to know this, but today was a perfect top down day, sunny and 70 degrees;)
Karl Prager

Hay Karl...go find another BBS
From a Canadian who for six months goes and sits in his 6 in the garage a freezes his buns off.
(just kidding ;)
Rick Crawford

I have triple weber (40dcoe)setup on my 73 TR6. I highly reccomend them. You would probably see a tremendous gain by using them because of all the other improvements you have made. They are without a doubt the ultimate in carburation and tuneability (each cylinder can be tuned - you cant do that with ZS or SU): if they dont work right it is only because they have not been set up right - and once set up there is no need to tinker or fuss with them. In my experience they are not finicky or difficult to drive in traffic - they are nothing but better (than ZS) all the way around!

I have a pertronix ignitor on my car too but I have also just hooked up an msd CD ignition which has given me more power and significantly better pulling throughout the rpm range - I highly recommend this!
Michael McLaughlin

With all of the mods you've done to your car,it would be a shame not to open up the induction system. Since all carbs are going to need to be adjusted with your elevation changes,why not go with a fuel injection system? With fuel injection you don't have to do any adjusting after initial setup. TWM induction can supply you with the manifold and throttle bodies and maybe the injecters and computer or Haltech may have to supply the latter two. An unmodified TWM manifold gave me a 6
hp increase over a modified Cannon intake on some dyno testing I did a few years back. How are you planning on stopping the car after all these engine mods?
Mike Munson


Any idea what the TWM manifold, throttle bodies, injectors, Haltech controller and such are running these days? Hopefully the price has come down a good bit. Several years ago I priced out that system and by the time all the bits were figured up it was in the $4K-$4.5K range.


it has been a while for me too.I couldn't afford it either so I just learned how to tune the Webbers. I just carried a plastic box with jets in separate compartments. I also use EGTs to tune.
Mike Munson

This thread was discussed between 20/11/2001 and 28/11/2001

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