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View Full Version : SEFI - what's the real impact on idle?


PTAddict
05-24-2007, 10:26 AM
I'm trying to choose a controller for my LS7 swap. I've used the Big Stuff 3 with good results on my previous LS1 swap, but it's a bit bulky, must be mounted inside the cabin, and lacks knock sensor capability with LSx motors. I'm also looking at the MEFI4 unit from MSD (formerly from UMI Racing), which is smaller, can be mounted in the engine compartment, and supports knock sensors - but is bank-to-bank only. I've only ever used SEFI controllers myself.

Is there truly a significant difference in idle quality with SEFI over bank/bank, in people's personal experience? I plan to use a fairly big cam, and the Pro Stock type of idle gets old pretty fast.

Thanks in advance ...

Edit: I do know that there is a difference with large injectors, due to the injectors firing half as often with SEFI and therefore minimizing injector opening time issues - but the stock injectors on an LS7 are not that large (42 lb/hr).

Scott

camcojb
05-24-2007, 01:09 PM
I'm trying to choose a controller for my LS7 swap. I've used the Big Stuff 3 with good results on my previous LS1 swap, but it's a bit bulky, must be mounted inside the cabin, and lacks knock sensor capability with LSx motors. I'm also looking at the MEFI4 unit from MSD (formerly from UMI Racing), which is smaller, can be mounted in the engine compartment, and supports knock sensors - but is bank-to-bank only. I've only ever used SEFI controllers myself.

Is there truly a significant difference in idle quality with SEFI over bank/bank, in people's personal experience? I plan to use a fairly big cam, and the Pro Stock type of idle gets old pretty fast.

Thanks in advance ...

Edit: I do know that there is a difference with large injectors, due to the injectors firing half as often with SEFI and therefore minimizing injector opening time issues - but the stock injectors on an LS7 are not that large (42 lb/hr).

Scott

I've made over 1000 hp and run 95# injectors with bank to bank, no idle issues.

Jody

PTAddict
05-24-2007, 01:27 PM
I've made over 1000 hp and run 95# injectors with bank to bank, no idle issues.

Jody

Thanks Jody, I should have known that if anyone would had put this to the most extreme test it would have been you! Since I'm settling for a completely wimpy 600 HP or so, my guess is I'll be fine with b2b.