_Remi

Hi all,

I have a 67 coupé with a 289 and the Performer RPM kit (heads + cam). It is on the other side of the planet and I get to enjoy it when I am on vacations (car is in France and I live in California). I am mentioning this because it means that 1/ I need reliability to enjoy the rare time I have with it and 2/ it can be difficult to find knowledgeable persons to tune it properly. That said, I have not been really happy with the way it has been running for the past two years. I lost quite some power after shipping it over there and driveability is not ideal at low RPM. This is after a couple trips to the best mechanic in the area...

Anyhow, I want to go EFI for the following reasons (in that order):

- Better driveability (smooth at low speed, crisp throttle response, more power at high RPM)
- Easier to tune
- A little bit more MPG

I don't want to start a carb/EFI debate but I do have the following questions:

- Is there a clear winner these days on the market? Edelbrock? Atomic? FAST?
- Not sure I understand the returnless/return distinction, what is there to know?
- I was told that the setup I have is not great in terms of low-end, will it help? I want to be able to floor it below 2K RPM without worrying that the engine will ping or die.
- Does the gear ratio that I have (3.8 now) have an impact on the tuning?

Thanks a lot!

67mustang302

Well, with your setup a carb should run fine (a decent one), but if the car is in France...good luck finding someone in Europe that can tune a carb right. The US is pretty much the only place you find carbs still widely being used in performance cars. What fuel are you using? And did you flush the tank? It might be something as simple as crud in the system clogging some jets up. It could also be a fuel issue, Europe has different fuel blending that the US; the carb might need to be retuned to account for the change in fuel (ie, if the fuel is more highly oxygenated, then the carb will lean out unless it's jetted up).

As far as EFI, it depends on what you want vs what you have to spend. I use FAST myself (XFI 2.0), they have a proven record on and off track, with some of the best performance/$$ (plenty of winning race cars running FAST). They probably have the best tuning software on the market, hands down. Not in terms of what it can do so much (though it does a lot), but in terms of UI...it's really easy to use and navigate (once you understand what all the stuff in EFI does). The XFI does has a crapton of tuning options in it though, lots of little things and big things. They have a newer EZ-EFI 2.0 that's a considerable improvement over the 1.0 version, that includes timing control. You could wait a bit longer, maybe another 6mo-1yr and their newer Sportsman EFI will be out, which is basically a dumbed down XFI...the simplicity of the EZ system but with the XFI tunability. It won't have all the bells and whistles of XFI, but will still have the same fuel/timing tuning controls plus a few extra things, and is fully tunable.

As far as return vs returnless....in a return system the fuel comes from the tank/pump, goes up to the injectors, and the unused fuel continues past the injectors in a return line back to the tank. A regulator sits between the injectors and the tank in the return line and regulates how much fuel gets returned back to the tank in order to control pressure. This is the preferred system since it tends to provide a more stable fuel system pressure. A returnless typically uses a PWM type controller to pulse power to the fuel pump, in order to cause the pump to run faster or slower to control pressure. So the pump speed varies with the amount of fuel the engine needs to maintain pressure. Returnless are a bit more simple to plumb since you have to return line, and work when you don't have an easy way of getting the return fuel back to the tank.

As for your setup, yes, it's not going to be stellar on the low end. The RPM package is decent, but is a bit older in terms of technology in regards to the cam (so you're going to have a bit more sacrifice in terms of where the power is). You're not going to be able to stand on it under 2k rpm and not have issues other than traction in 1st gear. You can damage the engine with detonation or you can lug it and beat up the bearings. Performance engines with manuals aren't designed to be driven at lower rpm. In an auto with a good converter you can get away with it because the converter will spin up to the flash rpm, so you're never really running it at low rpm.

Honestly though, I think you probably just have a fuel problem. If it started running poorly as soon as you began driving in Europe, my guess is it just needs to be tuned for the fuel. No sense in spending thousands on EFI if a $20 set of jets will fix it.

clowe1965

If you still want EFI look into picking up a foxbody setup while you're in the states. Lower and upper intakes, MAF, wiring harness, engine computer, 02 sensors and harness, plus a few other odds and ends. It won't be a complete bolt on experience but the only thing that you'll have to fab should be small brackets for the throttle or holding hoses/wires. You'll also need an inline fuel pump, block off plate, and to run a return line. You could feasibly do this for less than $1000.

I agree about the fuel problem. I'd try going to somewhere in Britain for carb tuning, you might have better luck ( my impression, not really sure).

There are also some TBI kits that are pretty much plug and play. Not the best for performance and efficiency but they are an improvement over a low cfm carb.

Starfury

I'm with 67mustang302, Remi, I think your issue is fuel related. I'm pretty sure euro "petrol" is blended differently than the stuff here, so I bet your carb just needs a bit of adjusting.