steve8586iroc

Holley has a new speed density management ecm that is a sequential fire system. What would the benefits of this type system be. The ecm runs about five to six hundred dollars, is it worth it?

Has anyone seen the ad or checked it out on Holleys web site?

[This message has been edited by steve8586iroc (edited September 24, 2000).]

[This message has been edited by steve8586iroc (edited September 24, 2000).]

Randy92Z

iTrader: (3)

Ive been told that sequential EFI helps emissions and a little on MPG. If you were to build a 500 hp EFI engine batch fire is better. So Im told.

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8Mike9

You should dig into it a little deeper...you won't be able to just install a new ECM and have Sequential Fire...our injectors are tied together, so you'll either have to rewire them, or maybe the kit comes with a new injector harness?

It makes sense though, and shoudl squeeze a little more out of the fuel system, both in effiency and power, over a batch system like we have now. But I'd wonder if the cost would justify the gains...and whether you would be better off spending the $$ on other mods.

It might be a better idea for someone who is converting to TPI and hasn't spent money on a managmnet system yet.

Brent

iTrader: (1)

I've been reading the GMECM for a while and the consensus there seems to be that sequential injection doesn't make more power at WOT. It only benifits idle and part throttle driving and emmissions. As I understand it, high HP setups with extra large injectors can gain idle and drivabilty quality using SEFI.

steve8586iroc

It just seems to me that the injectors would run more efficently only having to fire once per combustion cycle rather than four times per cycle. I also think that the injector impedance is different between the two systems. At least I thought I read that somewhere.I'm thinking it was an article about the buick turbo sfi system. Any way I thought a cooler running injector would have better performance at all engine speeds.

Just my .02

Steve

scooter

iTrader: (11)

I was looking into sequential EFI a while back. I wrote to a guy near me at Englishtown. He told me that unless you have a high horsepower application seq EFI is not nessesary. Also the sequential DFI is over $1500 or something. Much more expensive than regular DFI. I think the new Gen 7 DFI comes sequential/ non sequential standard. But it is also supposed to be a lot more than the current DFI. Other systems may be cheaper though. One thing better for seq is that it isnt as hard on the fuel pump. With 4 injectors opening at a time it shocks the system easch time a bank opens. If you were to look at the fuel pessure as a graph on batch fire it would probably look like a saw tooth wave whereas seq would probably be a lot more steady. Unless you have the time and money to spare I wouldnt bother. Low hp apps dont gain much from seq.

James

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