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EFI conversion of TR6 carb. version


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Hello,

I was wondering whether anyone in the forum have experience in converting their TR6's from carbureted versions to EFI. It looks very tempting to convert due to; power, economy, running etc. I've been looking at www.Patttonmachine.com and www.classicfuelinjection.co.uk. Any experiences regarding; quality, performance, installation etc.

Thank you for your help.

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Hi and welcome. I know a few people that have the Rick Patton ful injection and they do enjoy the improved starting from cold, smooth acceleration and better reliability than the Strombergs. I doubt you would see much increase in HP without other mods to the head and camshaft.

Stan

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Go ahead and do a search in the forum. Lots of EFI talk already.

I converted from carbs to EFI

- PI Throttlebodies

-ECU Ecumaster Black

-Wasted Spark ignition

-280° Kent cam

From my previous Carb Config with 270° Kent cam (140 HP) to my new EFI Config with 280° Kent cam I ended up having about 170 HP and all the other advantages of EFI......

Jochem

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If the intent is for bragging rights over a pint, the formula for HP= (RPM*Torque)/5252 is good guidance. If your engine can keep its BrakeMeanEffectiveTorque up while RPM goes up, build a motor than can go to 7000 RPM. Racetorations can help with that. Otherwise, increase torque. Which is a function of displacement and volumetric efficiency, mostly. So, the biggest pistons you can afford, head work, compression ratio, valves, cams etc. Then, AFR for best power, basically 12.5. If you have 12.5 AFR, the motor doesn’t care so much if it comes from a EFI or a carb. Then, ignition advance for MaximumBrakeTorque at that operating point, unless you get ping. Research “spark hook tests”.  There is where EFI with ignition control can help. You can optimize the timing to achieve MBT at the full operating envelope and if you hit ping, add fuel!  A richer mixture cools the charge due to greater heat of vaporization, and burns slightly slower. You can’t do this with a dizzy and carb. If you decide on EFI, go full in with ignition control, sequential injection, coil packs etc. If I did it again, I would have built my bespoke tank with pump in tank, pressure regulator on outside of tank with bypass return right there, and one HP fuel line to the front and MAP line back to regulator on the tank. 

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CK is correct about increasing torque.  I went the direct route and added a supercharger.  

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Hi Mimosa, sooner or later the work and learning about EFI

will give a proportional result.

The Patton thing from my view is a very good solution for American market

where air pollution rules or availiability might regulate the tuning and the manifold.

 

The half way will give more than half the fun, no doubt, but you can see from others

experience it is like a drug. Good idea is individual inlet runners and ignition control.

You get some pretty horses and more fuel economy for free and that is an argument

if you spend time and money on the project.

 

I would not expect that a system out of the box, fitted without specific knowledge will

satisfy over a loner period. It needs the individual tweak and as that becomes very easy

and cheap compared with a Weber DCOE setup it would be stupid not to try to optimize.

 

Unfortunately I had to set several PIs in the nearer past and despite they all had pretty new

metering units none of them was at the perfect point to work. So will the EFI start whereever you buy it,

what system you will use and what setting you might copy from others, there will be a lot of potential hidden.

 

The difficulty is to build the hardware and understand all that details and get it work than later

together with the Laptop and Wideband Oxygen sensor.

The easy and sweet thing is to lean back and tweak it from the passenger seat to perfection.

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A point about individual runners. The runner length can be tuned to increase Volumetric Efficiency (= torque) at a particular RPM. Jaguar did some studies that achieved over 100% VE, but the torque band was pretty narrow. The other side of individual runners is deciding what fuel calculation type you want to use. Speed density calculations need a good manifold absolute pressure signal. Also, tip in throttle response is a big factor for driving on the street.  

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21 hours ago, CK's TR6 said:

A point about individual runners. The runner length can be tuned to increase Volumetric Efficiency (= torque) at a particular RPM. Jaguar did some studies that achieved over 100% VE, but the torque band was pretty narrow. The other side of individual runners is deciding what fuel calculation type you want to use. Speed density calculations need a good manifold absolute pressure signal. Also, tip in throttle response is a big factor for driving on the street.  

Most EFIs provide a smoothing tool to tame the pressure signal electronically from the manifold.

123tune for example is so lazy that the signal from a single WEBER DCOE can be used.

For EFI that is a bit too much because some hesitation in fuel management will occure.

We have to smoothen the signal become just suitable, but not more, not to sacrifice the crispy response

on pressing the pedal. From a point forward this will not be possible with a wild cam.

That point is sooner reached with a single throttle body like todays cars have and for

Triumph TR6 it is somewhere aroung the 280 degree cam.

At present we have a 300 degree cam tamed to provide the EFI with a proper signal.

It is taken from the original PI manifold that connects all the six runners.

 

Former ECUs and Software releases did not provide that function. I connected all

six runners with small tubes and let them feed a little box from where I provided a

tube towards the EFI. Was a bit tricky but also worked quite well. In those times the

rule was to use Manifold pressure and rpm for smooth cams and for wilder cams swap

to throttle position and rpm, called Alpha/n. I think the open source of Megasquirt, what

at that time was the ECU to choose, pushed the software into the right direction we have now.

 

It is quite simple: Look at the difference of the TR6 PI and Carb versions. They are more or less the same

except the PI manifold. So from my view it is okay to give the 6 individual runners a power increase of about

10-15 HP. Talking about VE we must accept that the size of the runners is a little bit big, especially the throttle

plates with 45mm would be good for 220HP.  Also the runners are a bit short but there is not much space to

extend without making a new inlet. We have to live with that but have the benefit of long stroke/short rods

what will increase low end power.

Edited by TriumphV8
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As Stan mentioned above, changing the fueling system leaving the cam and head in U.S. specification is of no use; no appreciable power gain with loss of originality.

Nothing I've seen in many years on this and other TR forums makes a compelling case for EFI over Weber DCOEs to bring a carb TR6 up to the P.I. level of performance given Weber's unmatched reliability, simplicity and longevity, arguably preserving the vintage cachet without loss of value while delivering the goods far into the future. The biggest factor in favor of EFI seems to be the pleasure some have hooking up a laptop to their [ cast iron, pushrod 1930s era technology ] engines - not a small thing for millennials and younger, even a codger or two in the mix. When successful, each case is unfortunately unique and would require an intrepid buyer in a sale.

There is enough TR6 tuning/calibration data for DCOEs freely available to get very close to a final setting nowadays.

Fitting a 6 throttle / individual runner system gives power increase without penalty, which camshaft, compression ratio and high rpm measures often exact. The CP cam and compression ratio are already on the edge for the era.

Tom

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There's lots of efi expertise on SIdeways with all types of Triumph engines. But like TimD I went for supercharging for torque, gobs of it at low rpm.

Peter

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I think the greatest advantages of efi come when using long duration cams as it is possible to achieve greater driveabilty with full engine management.

Certainly having one throttle per cylinder is a big advantage with long duration cams. I have two Stag engines on megasquirt using 285 degree cams and plenum intakes with a single throttle and apart from slight transmission shunt  below 1200rpm on a light throttle they are very tractable.

However I have a twin plenum Rover V8 with an unknown cam which seems to measure about 300 degrees on the inlet cam but the standard 256 on the exhaust with the same megasquirt set up and driveability of this below about 1600rpm is a PITA.

All these are set up on Alpha N as I understand the concept of degrees of throttle opening far easier than manifold pressure.

Where I get my cars set up on the rolling road,  the operator far prefers Alpha N as it is a set figure as opposed to manifold pressure which gives different results depending on whether rpm is increasing or decreasing so therefore needs an average of several runs.

The big advantage of the TR engines is the readily available PI manifold for longer duration cams.

It is a big job fabricating a single throttle inlet manifold for the Stag engine, making an 8 throttle set up would be even more entertaining. I have got 4 PI inlets but the port spacing isn't quite right and I am dubious about the throttle size for what is effectively two 1500cc engines!

Tom makes a very valid point about sale-ability after efi installations. I suppose the point here would be to keep all the standard bits to refit if the car was being sold, however how well a tuned engine with a long duration cam would run on twin carbs is debateable!

Neil

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My bespoke intake manifold has about 20” of runner length from the bell inside the common plenum to the intake valve. I’m guessing but that is about twice the length of the PI manifold? The runners have the same ID as the ported out head.  Single throttle body. 

68D472E1-B874-4F15-AF24-1A11523C6568.jpeg

Edited by CK's TR6
Clarity
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I already have on my 1973 TR6 a EFI conversion done in 1994 by Pumfords--Northampton ( now ceased trading !! ) which has proved to be very good, however recently I have been experiencing problems with the Bosch Air Intake Module which determines the mixture control etc , the result being that when the module does not operate properly the engine will not rev !!!

The Bosch module I believe is now obsolete, has anyone experienced similar problems with a Pumford EFI system which I am told was very popular in its day !!, if so what is the resolve to same, any sensible suggestions would be greatly appreciated

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