Change of induction.
Discussion
Right, where do I start this topic? Bit bored with the SU on my 6 pot engine. Now it's stage 2 head, nice ss manifold but carbs letting it down. What is best for a upgrade? HS8,s, webbers, bike carbs or new trick injection?I know about keeping it original, but it's my car.
Thanks for your ideas and comments.
Thanks for your ideas and comments.
Three dual throats. Weber, SK, or DellOrto ... in that order of preference.
Later, Spanish made Weber DCOEs sacrifice performance for the sake of improved drivability, by virtue of being manufactured with different progression circuits. Unlike jets, this can't be altered. Given the choice, get SKs or Dellortos over the Spanish Weber units.
For maximum performance, go with EFI with crank fired sequential control.
When you hear these engines eclipse 8,000 RPM, you'll fall in love with your car all over again.
Best,
B.
Later, Spanish made Weber DCOEs sacrifice performance for the sake of improved drivability, by virtue of being manufactured with different progression circuits. Unlike jets, this can't be altered. Given the choice, get SKs or Dellortos over the Spanish Weber units.
For maximum performance, go with EFI with crank fired sequential control.
When you hear these engines eclipse 8,000 RPM, you'll fall in love with your car all over again.
Best,
B.
I'm sure other owners will argue, but I wouldn't go with the 2500PI system. I had three 2.5PI saloons, and they ALL had problems with fuel system at some point.
The main issue is that the system is entirely machanical, and it wears out. The way the metering works, any fault which causes reduced inlet vacuum causes system to run rich, so even faulty ignition timing can cause rich mixtures. The main system has little rollers in, which control the mixture as they run up and down a sort of ramp, and as they wear the mixture goes rich, and it's not easy to adjust the mechanism.
So any faults and the gas mileage tends to plummet (like 10mpg - been there !).
I would say today, go for a good digital system (Emerald or Megasquirt perhaps, both on web) it will be far better, and you get accurate ignition timing too.
Or if you prefer - as stated above, triple DCOE sidedraught was the ultimate carb system before digital injection - but balancing/setup can be tricky with 3 twin carbs.
I remember there was a triple SU manifold at one time, but probably not around now.
I think the sound of that Triumph 6 lump is just beautiful from it's midrange upwards.
The main issue is that the system is entirely machanical, and it wears out. The way the metering works, any fault which causes reduced inlet vacuum causes system to run rich, so even faulty ignition timing can cause rich mixtures. The main system has little rollers in, which control the mixture as they run up and down a sort of ramp, and as they wear the mixture goes rich, and it's not easy to adjust the mechanism.
So any faults and the gas mileage tends to plummet (like 10mpg - been there !).
I would say today, go for a good digital system (Emerald or Megasquirt perhaps, both on web) it will be far better, and you get accurate ignition timing too.
Or if you prefer - as stated above, triple DCOE sidedraught was the ultimate carb system before digital injection - but balancing/setup can be tricky with 3 twin carbs.
I remember there was a triple SU manifold at one time, but probably not around now.
I think the sound of that Triumph 6 lump is just beautiful from it's midrange upwards.
Edited by RCK974X on Thursday 15th November 23:19
RCK974X said:
I'm sure other owners will argue, but I wouldn't go with the 2500PI system. I had three 2.5PI saloons, and they ALL had problems with fuel system at some point.
The main issue is that the system is entirely machanical, and it wears out. The way the metering works, any fault which causes reduced inlet vacuum causes system to run rich, so even faulty ignition timing can cause rich mixtures. The main system has little rollers in, which control the mixture as they run up and down a sort of ramp, and as they wear the mixture goes rich, and it's not easy to adjust the mechanism.
So any faults and the gas mileage tends to plummet (like 10mpg - been there !).
I would say today, go for a good digital system (Emerald or Megasquirt perhaps, both on web) it will be far better, and you get accurate ignition timing too.
Or if you prefer - as stated above, triple DCOE sidedraught was the ultimate carb system before digital injection - but balancing/setup can be tricky with 3 twin carbs.
I remember there was a triple SU manifold at one time, but probably not around now.
I think the sound of that Triumph 6 lump is just beautiful from it's midrange upwards.
Dependant upon the level of tune of the engine....Their will not be much advantage of doing anything other than swapping to SU'sThe main issue is that the system is entirely machanical, and it wears out. The way the metering works, any fault which causes reduced inlet vacuum causes system to run rich, so even faulty ignition timing can cause rich mixtures. The main system has little rollers in, which control the mixture as they run up and down a sort of ramp, and as they wear the mixture goes rich, and it's not easy to adjust the mechanism.
So any faults and the gas mileage tends to plummet (like 10mpg - been there !).
I would say today, go for a good digital system (Emerald or Megasquirt perhaps, both on web) it will be far better, and you get accurate ignition timing too.
Or if you prefer - as stated above, triple DCOE sidedraught was the ultimate carb system before digital injection - but balancing/setup can be tricky with 3 twin carbs.
I remember there was a triple SU manifold at one time, but probably not around now.
I think the sound of that Triumph 6 lump is just beautiful from it's midrange upwards.
Edited by RCK974X on Thursday 15th November 23:19
If you have built a very good straight 6 with all steel bottom end, major head work and an extractor manifold then swapping to tripple webbers would get more power. Without the rest of the engine to match the carbs it would be futile...
The Lucas PI system is a wonderful example of heath robinson engineering. Its mechanical with a fuel pump that gets red hot, a high pressure circuit that fires the injectors via a rotating shuttle device at 110psi It was first fitted to the Triumph but earlier the Maserati 3000 saloon. Their used to be an old saying that if a triumph fired on all 6 from cold the system was faulty...It can be very temperamental.
If you want an induction system to give you max tractability from a mild engine then switch to a Weber alpha , omex , jenvey type throttle body and programmable electronic system. It will cost you £2500 or so to do but will look nice, Whether the cost / benefit is justifiable , Thats your decision.
The existing carbs, or switching to an SU was always good for 150hp !!
N.
heightswitch said:
The Lucas PI system ... was first fitted to the Triumph but earlier the Maserati 3000 saloon.
Neil,I think that's 3500 coupe. then the Sebring, and the Mistral 3.7, and eventually, the Mistral 4 liter.
Best,
B.
P.S. I hope that wasn't too pedantic, but Maseratis were my first love, with three V8s in the family, growing up. Indy, Khamsin, Bora.
Yeah, I didn't even mention the fact that the fuel pump was a modified wiper motor !! Typical Lucas 'bodge' engineering. Having a wedge also, the pod lift motors (TR7) are also nothing more than modded wiper motors too.
If you want to be REALLY pedantic I think that Lucas system was first used on track cars, with a simpler metering system ?
I used 2 HIF6 1 3/4 SU on mine, with hot cam and flowed head - worked well, but did pink a bit after lead reduced/removed, even with different dizzy springs. I modded the manifold myself, (from a 2000 saloon) opened it out to size and redrilled the stud holes...
If you want to be REALLY pedantic I think that Lucas system was first used on track cars, with a simpler metering system ?
I used 2 HIF6 1 3/4 SU on mine, with hot cam and flowed head - worked well, but did pink a bit after lead reduced/removed, even with different dizzy springs. I modded the manifold myself, (from a 2000 saloon) opened it out to size and redrilled the stud holes...
Edited by RCK974X on Friday 16th November 20:51
Gary, at TWM Induction produced a nice TR6 intake manifold for Weber carbs. So did Cannon manifolds. There are several types of throttle bodies available, that use the DCOE style mounting flange, and you can have injector bungs welded to either of the aforementioned intake manifolds. You can produce a very nice EFI system for a TR6 engine, if you're so inclined.
As a matter of fact, there are a good number of small diameter TBs from current/recent production cars, that are available from breakers' inexpensively. Having a competent shop fabricate a manifold to mount to shouldn't be too expensive. You could probably create something very nice yourself.
Best,
B.
As a matter of fact, there are a good number of small diameter TBs from current/recent production cars, that are available from breakers' inexpensively. Having a competent shop fabricate a manifold to mount to shouldn't be too expensive. You could probably create something very nice yourself.
Best,
B.
I'm running twin HS8's on my 2500M. They dont seem to offer much over 6's. I've been considering how to achieve more power too, I'm trying to decide between pouring cash into the Triumph engine vs a more radical route. I do like originality but ....... I have been contemplating the plausability of going for a 3.6 Speed Six!!
Possibly look for a wreck and have a go as a long (very long) term project....
Possibly look for a wreck and have a go as a long (very long) term project....Gassing Station | TVR Classics | Top of Page | What's New | My Stuff