Triumph TR6 Inline 6 EFI Opinions / Options

[dave w]

I've been asked to help with a Triumph TR6 Inline 2.5 liter EFI project. The injectors are just behind the throttle blades, see attached pictures.

With the injectors behind the throttle blades, has me thinking the fuel pressure regulator should be vacuum referenced, opinions welcomed.

I'm thinking an OBD1 1227730 $A1 3.1 V6 .bin (modified) would be a good starting point, opinions welcomed.

The current intake does not have an IAC which has me thinking a good plan is to install an aftermarket IAC, opinions welcomed.

The each injector measured about 2.5 ohms which has me thinking a good plan would include a resistor to match three 3.1 V6 injectors in parallel, opinions welcomed.

The distributor is set up for computer controlled spark advance, a good plan in my opinion.

Thanks in advance for your thoughts,

dave w

[mekkis]

Good lord, I am a fan.

[Xnke]

Why not just use a standard TBI computer-it would run much better once adjusted for displacement.

Although I am not sure which ones speak ALDL hi-speed, that could be an issue.

[sturgillbd]

Disregard.

[Xnke]

did anything come around with this?

Being the 2.5L I6, maybe the 2.8L TBI S-10 computer would have a good starting place-but I think it's 160baud only. The old triumph 2.5L heads aren't exactly fantastic, but they are pretty close to the port flows and valve sizes of the 2.8L iron heads.

Also I think doesn't the 7730 have a TBI option where it would handle the 15ohm TBI injectors? If so, I might try to find a pair of high-impedance injectors to replace what's there and run them directly, no resistors. If you choose to run series resistors, though, I guess you could-they will need to be 25W 7R to 10R.

[Six_Shooter]

Honestly, I'd go Megasquirt on that. The lack of IAC will make any OBD1 GM ECM throw a fit. Yes it can be tuned out, but is sometimes a lot of work to get everything shut off and made to ignore the IAC.

The low Z injectors also don't lend themselves to the '7730 well either. A '7749 set up for timing Low Z injectors would likely work better, but they can be difficult to find.

Yes, vacuum reference the FPR. Pull vacuum from behind both throttle bodies. Using a small reservoir will help dampen any pulses, though they should be minimal anyway.

[dave w]

Update: 2-18-18
An IAC was adapted to the intake. http://www.jegs.com/i/FAST/244/307016/10002/-1

Current plans are to use the TBI computer, that might still change.

MegaSquirt is a good option. Getting the things sorted out with the TBI computer is still a good plan. If MegaSquirt is decided on, the headaches of startup with fuel injection will be in the rearview mirror.

dave w

[Six_Shooter]

With the addition of the IAC I would look at using a '7730, with either $88 or $A1. $88 for dizzy, $A1 for DIS, though either can be adjusted to run the other type of ignition. Since both codes can be run in teh same ECM it's easy to switch between them to see if one works better than the other, or easier.

The TBI ECMs are slow and don't offer as much adjustability as the later ECMs. Also the fact that what you have is essentially the same as an MPFI system for location of the injectors, being post throttle plate, the MPFI based code seems to work a bit better.

[dave w]

Whatever we end up doing, I just need to be as good as this video: https://youtu.be/zmezGA7Qe9Y

dave w

[Six_Shooter]

Shouldn't be difficult to get better than that.

EFI shouldn't need a manually set high speed idle...

The only thing I see in your case that might cause issues in tuning is the single injector per 3 cylinders. fuel distribution may not be ideal.

[Xnke]

If he's using a carb intake, distribution should be as good as it was with the carbs. It won't be *great*, 2 and 5 will run slightly richer at low speed and 1, 3, 4, and 6 will run slightly leaner at high speed, but unless you're going racing and really pushing the chamber pressures up you'll be OK. Like I said-it'll be as good as it was with carbs, fuel-distribution wise.