Is anyone using EFI in a drag only, non-smog controlled car? If so, how is it working out for you? What brand are you using and how easy is it to tune? Any unusual experences or issues? TIA

Holley's Commander 950 is a really great set-up. Go with the wide band O2 and it will start/idle as easy as your daily driver and still deliver kick azz power at the track. The other nice side affect of using a totally user based programming system is the ability to record your run, go back to the pits and make changes without ever opening the hood-more timing, less fuel, whatever you think it needs. Not badly priced either, like 1500 for the throttle body style and 2400 for the full boogie direct port injection.

Does it require a laptop for making adjustments?

yes

EFI won't make any more flat-out power than a well-tuned carbureted setup. It will however work better everywhere else in the operating range of the motor and allow for much finer adjustability and driveability across the board.

And, as Dennis said, the datalogging and very easy timing and fuel table adjustability is really nice once you have used it. Want 1.5 degrees more timing at 4800 rpm when at 4 inches of manifold vacuum? No problem with EFI, just open up the spark table and change that cell.

Also, the EFI system will compensate automatically for different enviornmental conditions such as temperature and barometric pressure, whereas with a carb you may have to tweak jets and airbleeds depending on what the ambient conditions are like to keep maximum power.

And Pat, yes, you will need a laptop to tune the system. The only system I can think of that doesn't need a laptop is Edelbrocks with the little handheld programmer, but that is a fairly limited system.

For a strictly drag car, I probably wouldn't bother with the added cost and complexity of EFI as a carb will do just fine at WOT... which is where the throttle should be as you are headed down the 1/4. If you are looking to improve your timeslips by converting to EFI, you will only find disappointment. If you want something new to play with and be able to tweak nearly everything from the passenger seat, then you would be satisfied with the conversion. If you street drive the car I would say the justification to go EFI is a very easy choice, but for a drag-only car I think the money can be better put to use elsewhere.

I made the switch to EFI this year because I was not happy with the compromises needed with a blowthrough carbureted setup as I was previously running. The car made GREAT power with the carb, and was very smooth and driveable, but the compromise in a blowthrough setup is that to run a safe A/F ratio at heavy throttle means you run rich EVERYWEHRE across the board. Heck, I was seeing 12.5-13.2:1 when cruising, and about 12:1 at idle. The car ran very smooth and nice but I never liked how the plugs looked after driving around town, never liked the smell at idle, and being rich all the time had me worried about cylinder wall washdown. I don't have to make such compromises in the mid-ranges anymore with the EFI, but I also do not expect any more power out of the setup; in fact I may lose some as the carburetor serves as a "mini-intercooler" in a blowthrough setup such as mine as the fuel has a longer path to evaporate and absorb more heat from the intake charge. This effect isn't as pronounced with an EFI setup with injectors spraying right at the intake valves. Again, the biggest improvements to be made with EFI is at start, idle, and midrange driveability, not WOT power. Just don't go in with false expectations.

Troy

Thanks, Troy for the excellent explanation. You confirmed what I suspected. I wasn't really planning on going to EFI (one can buy a lot of jets for the price of EFI). National Dragster recently ran an piece on drag racing using EFI. All the users were quite happy with it but none said they were any quicker. One of the neater things mentioned was the timing control. Of course, something similar can be had with a MSD programable box. The precision with which the mixture can be controlled is impressive, but as you say, at WOT a carb works great. If it didn't, there would be a lot more EFI racers out there.

I've run EFI for about 10 yrs and have logged probably 1000 passes with it at the track. I've also tuned many EFI drag cars and done several back to backs on the dyno with EFI and carbs.

The info above is good. WIth a properly tuned carb like any HP Holley, you probably won't pick up any HP (when using the exact same intake manifold). However, for most people that don't have well tuned carbs, you can probably tune the EFI easier.

If you could spend a day racing with an EFI person, I think you'd be impressed. Take a HOlley Commander 950 and FAST offers similar features:

1) Internal datalogger, no laptop needed in the car, you can datalog and review the pass.
2) 16x16 timing map. You program timing not only be RPM, but by 16 load points. This helps a lot with the converter tuning. ALso is great to soften the launch to stop spinning if necessary.
3) Wideband O2 feedback. You can monitor the actual A/F ratio or run closed loop at WOT to maintain it.
4) Easy changes. Go to the track and put in the tuneup you want. Easily change anything.
5) No hicups or hesitations during burnout, stage, etc.

I'll never run a carb in anything I do again. The advantages are even greater for a street strip car.

Obviously carbs work well as witnessed by the numbers, but once you see EFI in use and see some of the guys winning (which are out there, but not a lot) you can understand the benefits.

I use a Microtech MT4 ECU but will switch to an LTX8 unit with ignition.

Works superior, best buy i ever did.

Adjustments with laptop or hand controller.

Yes a carb can run great, but it is a heck to tune and compensate for wheather, temp etc.

I can warmly recommend Microtechefi.com

Congrats to Godsend that made a 8.88 run today on the 1/4..EFI works;)