Carbie's or PI

[Yeahbabytr6]

Before I get to the question, here is some history. I have owned my 73 Yank version TR6 for 6 years. Yeah I know the steering wheel is on the wrong side, but what the Hell, they are all on the wrong side over here(USA). I have had nothing but problems with the stock Zeniths for that amount of time. The engine has been rebuilt, .20 over pistons, head shaved .25, mild street cam, intake ported and polished, header pipe, 2 sets of rebuilt Zeniths. I recently purchased a complete PI system from New Zealand.

 

The big question here is,,,,,,,,,, If you were given the chance would you switch to SU HS6's or to the PI system. Being ingorant of PI system's to the TR6, what would be most of the drawbacks or pluses.

 

I await your groans of wisdom.

[Andy Moltu]

As you are already on carbs I'd suggest a triple Webber set up.

 

However if you can lay your hands on a good second hand PI system then that will be cheaper but will involve more plumbing as the US spec car won't have the high pressure fuel lines, the fuel return pipes nor the UK spec fuel tank.

 

There's not a huge difference in performance as a generalisation the Lucas PI system when well set up will probably give better economy. The dowside is that if you heavily tune the car it can be harder to minimise the flat spot that can occur around the 4000 rpm range without compromising top end performance.

 

The twin carbs (SU or Strombergs) are capable of reasonable performance but won't have the potential of the other two set ups.

[Richard Crawley]

Hi & welcome to the forum; as you’ve already got hold of a PI system, no doubt in my mind go with that but make sure everything is in good condition. To get the best out of it you will need to fit the larger valves the PI uses (if you haven’t already) & you will also need to modify the dizzy to suit the new cam, head & improved breathing.

 

At the risk of upsetting the other guys who have them fitted, I would forget the SU’s (although they are better than Zeniths!). If you really must have carbs, Webbers are the only option as far as I’m concerned.

[Tom Fremont]

Hi Yeah and another welcome,

 

This is a well-worn topic.

 

Stromberg emissions carbs are very difficult to adapt to non-stock cams, which likely relates to your problems. My hat's off to you if you undertake ( and achieve! ) success with a P.I. conversion, a feat seldom attempted here ( USA ) and arduous indeed.

 

When I discovered the limitations of the Strombergs after changing cams / compression a friend suggested Webers ( that's with one "b" - Edouardo is probably rolling over in his grave with the rampant use of double "b"s ), and supplied me a used set and rebuilt them with me. I was left to calibrate them using what advice I could get over the phone, which took a few iterations to nail. When I got it about right, I took a TRF / CAR components mechanic for a ride and I still remember his remark, referring to Charles Runyan's TR5 for comparison: " Fuel injection didn't do much for that car. "

 

The car was transformed and a love affair has ensued. 70,000 trouble free miles later this 1960's vintage used set is still running flawlessly. A NOS set of Italian Webers is about to be installed on my current project as well. I'll never go back, and no form of P.I. or supercharging has any appeal to me having known the excellence of the Webers.

 

I don't fault the U.K. owners for preferring their P.I. systems - after all, they're original, somewhat exotic for the rest of the world, and do deliver the goods for them. A big factor has to be the exellent support infrastructure over there, something virtually non-existent here. I would be hesitant to take one beyond towing distance in the U.S.

 

Webers have decent support over here ( and in the UK, too ). Pierce Manifolds is the leading supplier and dispenses advice readily.

 

If you want to see some examples of Weber equipped TRs ( up to 230 BHP ) look at the Racetorations website; www.racetorations.co.uk

[Richard Crawley]

When I discovered the limitations of the Strombergs after changing cams / compression a friend suggested Webers ( that's with one "b" - Edouardo is probably rolling over in his grave with the rampant use of double "b"s )

 

I don't fault the U.K. owners for preferring their P.I. systems - after all, they're original, somewhat exotic for the rest of the world, and do deliver the goods for them. A big factor has to be the exellent support infrastructure over there, something virtually non-existent here. I would be hesitant to take one beyond towing distance in the U.S.

 

I’m not a historian, not very good at spelling & didn’t appreciate the significance of the single ‘b’; you live & learn!

 

I do think you have a valid point regarding the availability & support for the PI system ‘over the pond’ which, I must admit, I really didn’t think too much about when I posted. On balance, I still think a well sorted PI delivers a more rounded performance for a road+ car but, as I already stated, Webers would definitely be my second choice.

[Roger H]

that's with one "b" - Edouardo is probably rolling over in his grave with the rampant use of double "b"s

 

I must admit to this one also...........maybe we can blame it on 'Mark'.....???

[Yeahbabytr6]

Thanks for those who replied so far. Webers, well in my neck of the woods, Pacific Northwest USA, Webers are not well thought of. I have asked several people and have advised not to go the Weber route. How about Delorto. If so can you all steer me in a direction of model numbers and jet sizes.

 

The reason I went with the PI setup is I really like the looks. I have also thought about retrofitting the Lucas PI with a Megasqurt CPU and getting some other injectors to fit the stock throttle bodies.

 

Any ideas on this one.

[boxer]

send me your email address and i,ll send you some pictures of my usa cc model converted to injection if that doesent make your mind up nothing will

Bob

[jonlar]

If you have got a high comp head available, no question, go for the PI with a "warm" cam, then get MU calibrated and tuned accurately timed on rolling road, then try it on a real rosd and let us know!

[Tom Fremont]

Webers, well in my neck of the woods, Pacific Northwest USA, Webers are not well thought of. I have asked several people and have advised not to go the Weber route.

 

Such perceptions are to be credited for keeping the Weber club membership somewhat exclusive

[heliguy]

Hello Yeababy?

 

I am in Victoria B.C., not too far from your neck of the woods. I too am converting a carb car to PI, in fact most of the work had been done by the previous owner ( my father ) The fuel tank was modified, a couple of lines are run to the engine bay, the gas pedal system get modified to a cable system for the PI set up. As has been mentioned before getting a good used PI set up is not that expensive..........I have bought a couple of sets off of E bay and the average is about 200-300 bucks, depending upon how complete the set is. Most, if not all of the refurbishing work you can do yourself, but the final set up should be entrusted to someone who knows what he is doing/has the flow bench to do it. There are a couple in the UK ( shipping, about 40 bucks each way ) There is a company in Michigan, Kinsler i think the name is. The advertise experince with lucas stuff, but have not talked to anyone who has dealt with them. There was a really nice converted TR250 at the Van Dusen all british field meet a couple of weeks ago in Vancouver.............if you saw that car you would install the PI in a heartbeat.