FAST XFI thoughts?

[Alex]

I'm currently mulling over whether or not I want to buy an XFI.

My digidash will handle all data/dash logging, my ISIS will handle all electrical (fuel, cooling, etc...), so I just need it essentially for a/f and spark.

It seems like a decent solution, especially the auto-tuning feature in V2 (so I can drive around until I get on the dyno and get it fully tuned), but I wanted to get your guys' thoughts of it versus an OEM LS harness.

The way I currently see it is it seems a lot like an iSIS unit - overkill for my build, but it makes things soooooooo much easier to wire and troubleshoot that I'll pay the premium without giving it a second thought because of all the benefits.

 

[J. Salmon]

I have the XFI, but only because I have stack injection. We have an LS3 in our Cobra with the OEM harness. It's hard to find fault with it. The things pulls like a freight train. Throttle response is awesome, the engine behaves... well like OEM.

 

[Will Campbell]

But Alex-- that's not a carb, is it? :stunned:

 

[Alex]

But Alex-- that's not a carb, is it? :stunned:

I blame Fran - he didn't account for somebody wanting a tall deck + mozez heads + 12'' runners on a carb intake manifold :laugh::laugh:

So I'm forced to EFI; bah humbug.

 

[Bill Musarra]

I can't comment on the LS setup. I do have the XFI/XIM setup. This system is a dream. It is easily tuned and any changes that you want are easily performed. All tables can be saved so, if the car starts to act erratic, just go to the file and reaply it, and bingo your back on the road. The nice part is once you dyno the chassis, setup one table for street, and one for track. Then you can drive to the track, and with a laptop change the tune for the track. Then after the day is done, retune and drive home without the erratic behavior of a race car.
I wanted the distributorless setup. We had some problems that can be attributed to a new setup. But now that the throttle bodies are tuned and the program set it runs flawlessly.
Now to set the clutch and I am on the road.

Bill

 

[Rich E.]

Ever looked into Holley EFI systems. I buddy of mine put one in a BMW M3 with a LSX motor. Works really well and was easy as pie to setup.

 

[Alex]

Holley has enough problems w/ carbs these days; I don't think I want to see their idea of fuel injection management! :/

 

[Randy V]

While I gave no experience with their EFI systems I can speak to their carburetion,,
95% of Holley's problems are caused by the "experts" that decide to play with them and screw up some pretty darned good factory calibration.
The other 5% I am leaving to the flaws of their own past internal manufacturing process which seem to have been resolved since they reorganized around 2 years ago..

 

[Doc Kaler]

Alex,

I am using the XFI/XIM setup with the FAST LSxR and Williams 105mm DBW throttle body. BTW, I have a DBC 104mm throttle body NIB if anyone is interested. I have the GM ECU as well "just in case" I don't like the way the XFI/XIM manages, but doubt that.

 

[Alex]

Looks like I"ll probably go the FAST route then - the one thing I really like is Verson 2 auto tunes the ve table, so I can drive around and get things done (e.g., exhaust), then get it tuned at the very end.

Btw, what's with the XIM ignition kit? I thought that the fast xfi (by itself) also controlled ignition, no?

 

[Rich E.]

Holley EFI Catalog

Take a look. What could it hurt.....

 

[EGLITOM]

interesting

My holley works perfect right out of the box. AF ratio is spot on, Just had to adjust the idle AF ratio. Althouhg it runs pretty good i will tinker with it a bit, but only with the accelerator cams. It has the 330 cams installed which may be a bit big. I have slight hassitation if i step in at around 3000 RPM until 4000 RPM. It may have to do with the 750 cfm pro carb beeing a bit to big for the 331 and the cam i have in this range, but i will give it a try to dial it out.

but this Fast part made me thinking also

Would this 1350 cfm unit on a super victor EFI intake

give me the possibility to reach drivability from idle(which i have) and even more top power than with the 750 carb.
I´m thinking about getting myself involved in building a megasquirt setup ( just like the idea of building it by myself and learning everything involved)
Would take sensors and Bosch injectors which are available here.

What you think ?

TOM

 

[Tom]

Tom,
Besides the FAST system have you looked into the Moates Quarterhorse? Cheap, scalable, and you can always limp it home since you are using the rugged factory ECU.
QuarterHorse for Fords [QH1] - $249.00 : Moates.Net

The QuarterHorse plugs into the J3 port, like a chip module, on EEC-IV and EEC-V through 2004 Ford vehicles. Here are the key capabilities:

- Datalogging of all sensors and values to the PC.
- True realtime emulation allows instant changes to any calibration parameter while engine is running.
- Box reading for EEC-IV/V.

You can change ANY parameter while the vehicle is running without disturbing operation.

Alex,
For LS, go here: RoadRunner Hardware : Moates.Net

 

[Andrew Robertson]

interesting

My holley works perfect right out of the box. I have slight hassitation if i step in at around 3000 RPM until 4000 RPM. It may have to do with the 750 cfm pro carb beeing a bit to big for the 331 and the cam i have in this range, but i will give it a try to dial it out.

Would this 1350 cfm unit on a super victor EFI intake give me the possibility to reach drivability from idle(which i have) and even more top power than with the 750 carb.What you think ?

TOM

Hi Tom,

A properly tuned 750 should work great on a performance 331. If o/all mixture is good on a steady pull, it's probably a secondary pump shot issue. I often used a small pump cam on the primaries and a pink pump cam on the back, and you may need to play with pump shot duration by changing shooter size too.

As for your EFI question, going too big on a carb creates problems that are related to low velocity. EFI like the one you pictured meters fuel on manifold absolute pressure and even an open plenum intake and a large throttle body should produce excellent drivability and response from idle up. Having said that there's probably not a lot of top end to be gained, possibly none, unless your current 750 is not optimised and/or is sitting on a dual plane intake manifold, or an inferior single plane.

Cheers, Andrew