Opinions on my combination thoughts.

[JoshStratton]

I was just gonna mention that... The ZZ4 is still a VERY nice engine combo for a daily driver and Accel sells an EFI system that is already setup for that specific engine.

Sorry, I think I lost where that was mentioned. Did you mean the
GM ZZ4 350cid (http://www.jegs.com/cgi-bin/ncommerc...29&prmenbr=361)

or the GM ZZ 383 (http://www.jegs.com/cgi-bin/ncommerc...83&prmenbr=361)

I think the compression of 10.1:1 on the first one is too high for EFI isnt it?

Thanks for being patient with me.

[JoshStratton]

but unlike a MAF style setup they are only so sensitive to changes under partial throttle.

This is something I still do not understand. I understand the concept of the speed density and how it will look up the pre-determined values for spark and fuel in a table based on the amount of airflow.

I guess I dont get the concept of the MAF style. I know you need a sensor between the air filter and throttle body that will measure the amount of air the engine is ingesting. I dont see how it uses that measurement to get the right spark timing and fuel needed. I can imagine it is probably some complicated calculation.

Being more advanced, is the probable extra calculation time from the MAF style EFIs noticeable in response?

[SSMOORE]

Your right A wideband o2 isnt a must. Atleast till you got to tune it. Still not a must but oh so much easier. All the systems I listed are good . Some are better for different combinations. Like for instance If your gonna run ac, the wot ac cut off is nice to have also ac idle anticapate. None of these aftermarket systems run a maf that I know of. Except maybe motec not sure. But I dont think he wants to sell his first born to get a motec so we wont go there.

If you want to run nitrous some of them have nitrous control for 3 or 4 steps. Nice feature if you have a need. The new fast xfi and the accel gen 7 have this.

Also theres nothing wrong with a big block. Yea a small block is lighter. but ask yourself this question. are you going to the track? Or are you looking for a good handling street car? If its a street car you can have decent handling and the awesome tourqe that a bb chevy can give you on the street. Makes for a fun car. Whats so nice about a bb chevy is that you can make decent power and awesome tourqe in a very streetable pkg. Much more fun on the street in my opinion than a high strung sbc.

steve

[Lowend]

Don't fear 10-1 compression, espically with Aluminum heads and F/I. fuel injected motors are capiable to running much more compression than carbed motors due to the better control of timing and knock sensors.

Don't get me wrong here, the Speed Density system is just fine for the kind of application you are dealing with. A MAF system still uses a MAP sensor (speed density) as a supplemental, the MAF gives an extra dimension to the readings. A MAF is basically a hot wire and measures airflow by how quickly the wire cools. It isn't magic, it just gives the ECM more data to work with when calculating. All of the current GM engines use a MAF system because it is very flexable and adapts well to altitude and temp changes. Rather than depending completely on pre set tables a MAF system has the ability to improvise and learn its permaters a little better

[JoshStratton]

I am a little worried about the BB because I would like to get as close to 25mpg highway as possible with this engine. I am not sure I can acheive that with the 502 and a TKO500.

I like the idea of using an MAF system, but it sounds like it isnt really necessary. This car will be a daily driver, but only Spring - Fall. I dont think I will need that much of an EFI system to get what I want out of it.

[SSMOORE]

25mpg is a lofty goal even for the 400hp small block. You can get better gas mpg with the fi and the tko but.. Thats close to what my 99 ws6 firebird would get cruising down the highway at 70mph.. It was a 330 hp ls1 with a t56 .50 od and im sure it was a little more aerodynamic and lighter than a second gen and was sporting the latest technology gm had to offer. So I would set my sites a little lower and be realistic.


steve

[SSMOORE]

Oh and I agree with lowend.. Get a gm crate engine that accel has a turnkey kit for. Saves you the hassle of trying to figure the whole mess out and tuning it would be a non issue. Thats all been done for you.

[JoshStratton]

Was that the ZZ4 350 or the ZZ 383? I kinda figured it would be unrealistic but would like to get as close as possible. I would be extatic if I could get 20.

[SSMOORE]

I think its for the zz4 350 engine.

accel bank to bank = 77350

accel seq with sync distributor= 77350s

accel seq with sync distributor and wideband o2= 77350ws

steve