TR6 woes: which carb option is best?

So, I finally received my TR6 project car. The Stromberg carbs on the car need to be rebuilt. Found an MG/Triumph specialist nearby. He says as long as we're rebuilding the carbs, maybe we should look into replacing them with a pair of SU or Weber DGV units. 

He argues that both SU and DGV are easier to set up, tune, and maintain for a street car compared to the Strombergs. 

Here are some reasonable off-the-shelf options...

http://www.mossmotors.com/Shop/ViewProducts.aspx?PlateIndexID=111367

http://www.mossmotors.com/Shop/ViewProducts.aspx?PlateIndexID=59274

There's also the option of triple Weber DCOE or Triple SU carbs. I think tell be easier to deal with two carbs rather than three, so I'm leaning towards the dual SU or DGV options.

What say you?

Six Mikuni FCR39 carburetors, each of which fuelled a DR-Z 400. That way all of your mixture-distribution issues go away.

Easy is twin Mikuni flat side carbs. Supposedly outperform SUs and webers. Otoh I have a set of rebuilt stromberg 175 cds laying around. Another option is convert the beat strombergs into fuel injection and be done with carbs (why I was hanging on to my set). In my mind Fuel Injection >Mikuni>Weber>SU>Strombergs although die hard Brit fans would tell you SU all the way. Nothing inherently wrong with strombergs, just fewer options for needles/jets. Ninja edit - btw - rebuilding your carbs costs about $30 in parts. Replacing them costs well north of $500 and upt to about $2,000 for triple SUs. FI conversion can be done well under $500.

Strombergs are cheap to rebuild if the throttle shaft bushings aren't oval and the fixed jets aren't worn out.  The ones on my TR6 have 25k miles on them *after* being rebuilt, and they had at least 70k before that.  I replaced the jets and needles, and used slightly oversize throttle shafts from Joe Curto.  Never had an issue.  If you need more adjustability than the stock needles allow, adjustable needle jets can be fitted.

I've never tuned SUs, but I've never felt the need to replace Strombergs for a mildly tuned TR6.  One advantage of the Strombergs is that the air valve is less susceptible to wear because of the rubber diaphragm.  Then again, you need to replace that every several years.

For my autocross car, it's EFI all the way.

We switched our TR6 from Strombergs to SUs. No actual power gain, but the car now has great drivability. Cheap and easy swap that doesn't alter the look of the engine compartment. The Strombergs tend to run lean, as they were trying to improve emissions. 

In reply to LanEvo :

I like strombergs because they are so easy to convert to E85. 

Leave the needles the same and simply drill the jet out to flow 65% more. 

With E 85 and no other change the car will be about 15% more powerful. Not to mention E85 is often 20-30 cents a gallon cheaper  

If you also mill the head to increase compression you'll pick up even more power

In reply to LanEvo : what is your goal?  Three SU carbs are only a tiny bit more time to work on than two  Same with Strombergs  

on the other hand Webers really get expensive since you need to buy a whole series of Jets air correction meters Venturies and idle jets  

you see Webers don't automatically adjust to air density changes like Strombergs or SUs do

Dyno time is required to properly set things up and then to do a really good job requires Dyno time on different days with different air density  or you can wait because there is bound to be a day that changes enough for you to get a really good handle on what your car responds to. 

Nice warm dry day and have a thunderstorm roll in during the afternoon  is perfect 

buy and calibrate a good air density meter so when you don't have a Dyno handy you can change things according to what the air density does

Jaguars with three Webers make 15 horsepower more than with 3 SUs  but as air density changes the adjustment to maximum power is to raise or lower the jet a flat or two rather than tear the carb apart and change so much like you have to with Webers 

 About the downdraft Weber DGV's, They've performed pretty much trouble free since the late 1990's on my TR6. 'Always been an easy start cold or hot. From autocrossing to city driving it's done as good as an old carbureted engine can. The occasional 'run it through the gears' keeps it cleared out after putting around. 

 I don't know the best carb option... maybe just preference or opinion. Also, the throttle was much smoother and more uniform after getting rid of the tired bell crank linkage.

Quick update: a buddy pointed me towards a complete Weber DGV setup for the TR6. Just $300 plus shipping. Two carbs, manifold adapters, filters, throttle linkage, and all associated hardware. Never mounted to a car. 

As someone who can't leave well enough alone, I'm likely to do cams and shaved head in the near future. So, the ability to easily increase flow is appealing to me. And I'm much more familiar with Webers since I run DCO/SP 48's on my race car.

For $300, I figured it was worth a shot. I was quoted $185 each to completely strip, clean, and rebuild the existing Strombergs back to stock spec; closer to $225 if they've got the emissions junk (I believe mine do). The complete Weber DGV setup will come in cheaper and it's something I'm more comfortable with. If things don't work out, I can always pass it along. 

In reply to LanEvo :

I approve of your logic, plus the webers will look great too.

Forget about the downdraft options.

If you want a reliable car with great drivability convert to earlier SUs

If you want to go racing your are stuck with whatever your racing organization allows, probably either Strombergs or Lucas PI.

The triple Webers look nice but are a waste of time on anything but a full on race car.  I picked up 3o bhp on my MGC with triple SUs - don't look as cool but work very well and much easier to tune.