Dyno Results: FiTech EFI Versus 750 Carburetor

Dyno comparison of a FiTech Go EFI 4 system and Quick Fuel SS 750 carburetor on a 427 Small Block Ford at Prestige Motorsports.

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[headlesnorseman]

Love these videos that post peak numbers when the MAIN reason a fuel injection system is better is the area under the curve

[octaneartllc]

Prestige world wide, world wide, world

[RyL]

Peak hp/torque is nice, but seeing the entire curves would be better.

[axlegrind]

forget peak horsepower numbers in a street car. the engine stays in the torque range much longer than it sees peak hp. of course you want the fuel mix correct at peak rpm but for the street you want the torque curve to be properly tuned along with drive-ability.

[josephloro]

i think the point of fitech is to have ur cake n eat it better mpg easy start on cold days n same hp as carb

[NickKautz]

I tried the FiTech for a couple months, ended up switching back to Holley 750. It takes a while for the fitech to learn fuel trims for your application, during that time your motor will run like crap. Also, it's a road-race car and even after it was calibrated, it struggled to transition smoothly from heavy decel (lean) to on-throttle (rich) without stumbling for a few seconds each time. It's probably possible to tune-out that stuff eventually but you'd really have to dig deep into their controller software, which has no fuel map, only afr targets.

[coryholbrook]

See, that’s the problem with all these carb to TBI FI comparisons, no one does it properly. The carb is tuned and the efi isn’t given a chance to learn or the carb is box stock but the efi is tuned. This is too biased and too simple. Does the average carb user just slap it on and call it good? I’m a beginner with carbs still but I haven’t left mine alone. I bought books and a wideband to help me learn about and get it right. Also one hp/tq number at a single rpm is too simplistic. The guys who are REALLY interested in this comparison will want to know more like all plots across the entire driving range and air fuel ratio control as well as mods done to the carb to achieve that performance. That’s where you can keep the carb tuning to the average user, jet changes, idle mixtures, power valve, secondary opening rate, squirter cam, etc. Maybe even some of the slightly more tunable restrictors available in the aftermarket billet metering blocks that are so prevalent now. That wouldn’t be a 3 minute video but give real hotrodders some credit. We’re not all like the modern muscle crowd of bolt it on and go.

[ViewThis.]

Hey FiTech make one of those that's super low profile for sitting on top of a Roots Blower so a person can get some hood clearance. There's no need for it to be that bulky when on top of a blower providing lotsa suction under the throats.

[Popsmke]

I would have loved to had a fitech back in high school. I hated cutting my car off cause I'd be constantly be praying " oh dear Lord please allow my car to crank." and I had a 70 Plymouth roadrunner. Sadly I no longer have this car but I have a 69 roadrunner.

[jasontrevis]

There a lot of comments regarding horsepower and fuel economy. The only way to really compare fuel economy between the two induction devices is to measure fuel used for identical load runs. Then compare the amount of fuel used against the horsepower/torque measured.

[Amilzera]

Fitech uncomplicated and simple, for V8 the best I've seen so far.

[craphittingthefan]

I use a 800 DP on my 408 Windsor, I am a good tuner on carbs my 408 makes 530Hp with 210cc heads, I believe after seeing this dyno test, I will stick to my swap meet carbs for my uses a daily driver, I could see this unit making sense.

[furyfantoo]

As noted, this dyno run was done solely at WOT, so a std mechanical distributor advance is sufficient. But the other big benefit to an ECU controlling an engine lies with ign timing at part throttle, in real driving conditions.  The max torque/hp from a dyno tells only part of the story - a well-sorted EFI system with ECU'd ignition will have more hp and torque *everywhere* - more area under the curve.  As an example - when the coolant temp and ambient is cold, any engine is going to respond noticeably to 5-10° more ignition timing, and an ECU will do that gradually, seamlessly, throughout the temperature range.

[stevesolo]

Just to note, if you have a beautiful engine like that you would think to have the carburetor set up correctly. You could hear the squirters needed to be upped a size or two, perhaps the accelerator pump as well. That is the beauty of carbs. Set up it would, at the very least, equal the injection if horsepower was your goal. But, when it comes to "set it and forget it" fuel injection is a godsend.
BTW: How did you pick the CFM size carb for this engine? There is a mathematical formula that will pinpoint the correct size.

[electronicatutorial]

It is not a competition of peak HP it is a competition of wich one is faster and that has to do with the power curves.

[michaelsimovic]

Had to make a few runs with the efi to get the best results I wonder if as much time was taken to optimise the best carburettor for this combo? I somehow doubt it

[roknroy]

1 tenth and 1mph, for about 1200.00 and labor, keep the carb

[jerrycordova]

I noticed the engine has a perfromer rpm intake which are dual plane. was there any issues with that or is that why it has a carb spacer?

[pepitomateo]

Sorry guys, I don’t buy this, I tried fitech in my car, it was a nightmare. Probably I noticed a bit more power in high rpm vs the carb probably cause of CFM capability but transitions were full of issues. Don’t mention slightly altitud changes, computer got crazy!
I also tried Holley sniper, I got really impressed! I works really good, just like a carburetor.

[jeffe]

I just ordered a built chevy 350 with fitech fuel injection hope its worth it