In an in effort to address the lean condition I have experienced at WOT from 4000rpm on up, I have installed "new style" 90lb injectors on my Xfire TBI units. I did this in conjunction with a rocker arm swap to 1.6 on the intake, giving me a .520"lift.
The motor has recently dyno'd 252rwhp SAE at 4800rpm prior to these mods. I have read that when using 90lb injectors, Bruce plumbed the fuel line so as to run the TBI's in parallel rather than series. I haven't had the opportunity to tune the Main Tables but have made the change to the injector BPW. I was able to put a scantool on the motor briefly and did notice that the INT (Have the BLM's locked for tuning) was going from lean to rich and back at idle or part throttle. Balancing the TB's significantly improved the surging however.
Long preface to the question(s).
What issues to driveability, emissions and performance should I expect to experience by running the TB's in series, understanding that the original setup ran slightly different injectors front to back?
Is plumbing the TB's in parallel meant to overcome the requirement for differing size injectors?

 

Nobody has any opinions or hunches? Or knows?

 

even though crossfires do have TBIs, this stuff would be better suited on the crossfire website.

 

I can't really see an advantage of running them in parallel or series. Either way they go blip blip. There is probably a reason but ask Grumpy/Bruce.
If this post doesn't get any more replies then it's going over to the DIY_eprom board.
90lb injectors on a crossfire making only 250rwhp is pretty big. No need to have such large injectors. You could have it running with the stock 67 injectors with a little more fuel pressure is all. At least that's what I've gathered. BTW, I do burn my own eproms so I'm not a complete idiot when it comes to crossfire.
Question, are you running the 7747 ecm?
If you're tuning the car and have the 7747 ecm you should think about using the winaldl software. It'll make the VE tables a one day deal. Timing on the other hand...hahaha, this is going to take a while longer. Thinking about running rich under part throttle and a bunch of advance but then I end up driving around town with my brakes...hmm...the trade off, oh well.
Like I said, I'll give it another day then move it. Do a search, might turn up some answers.

 

Jon,

Thanks. I have gotten some answers off-line. The 252rwhp translates to almost 320 crank hp. According to the BSFC, the 66# injectors that are standard with the Xfire would support up to 280crank hp. And I believe Bruce was also using 90# inj. for his Xfire albeit 355cid. Having done numerous dyno runs with a wb O2 sensor, I can tell you I am running out of injector. The bin file has them flat open at WOT and AFR climbs from 12.5 to nearly
14. from 4000 to 5200rpm. Consequently the hp curve tails off.
Here's what theHP and Fuel curves looked like.




edit by Tas: I fixed your pic.

 

320 hp and CFI puts a smile on my face .

 

TAS,

Thanks for the help. Thought I had done it correctly.
BTW, both those runs are SAE corrected numbers in the graph