Marc H's chip = supurb!

[Paul Workman]

As some know, I ported my top end and pulled the secondary hardware completely. Today we took the Z out to Galena, IL and back - about a 400 mile round trip to test the new setup and "play" on some of those nice twisty roads near the Mississip.

First impressions are the chip (programming) is a jewel!! I wasn't sure if I was going to like "all 16, all the time", and not sure how it was going to handle in traffic. In short, the drivability - including stop and go traffic - is better now w/o the secondary hardware - smoother. And, the throttle response is significantly improved as well. And, when I "get my foot in it", there is no hesitation as the secondaries come on (as there was before - like the secondaries of a spread-bore carb opening up).

Well, needless to say, the program exceeds my expectations so far. Can't wait to get the headers and exhaust on it next and then see what the dyno has to say!

Stay tuned! (so to speak!)

P.

[XfireZ51]

Originally Posted by Paul Workman

As some know, I ported my top end and pulled the secondary hardware completely. Today we took the Z out to Galena, IL and back - about a 400 mile round trip to test the new setup and "play" on some of those nice twisty roads near the Mississip.

First impressions are the chip (programming) is a jewel!! I wasn't sure if I was going to like "all 16, all the time", and not sure how it was going to handle in traffic. In short, the drivability - including stop and go traffic - is better now w/o the secondary hardware - smoother. And, the throttle response is significantly improved as well. And, when I "get my foot in it", there is no hesitation as the secondaries come on (as there was before - like the secondaries of a spread-bore carb opening up).

Well, needless to say, the program exceeds my expectations so far. Can't wait to get the headers and exhaust on it next and then see what the dyno has to say!

Stay tuned! (so to speak!)

P.

There really isn't any difference between running the secondaries all the time or running on just the primaries. At any given RPM x MAP, the motor will need only so much fuel and air. Whether the fuel is being delivered by 1 or 2 injectors doesn't change anything. The total PW will be the same or at least should be. One of the advantages of no secondaries is not having to tune 4 VE and SA tables.

[rhipsher]

I've never had a hesitation with the secondaries coming on. The power is on tap immediately. But I have heard others say that they do notice a hesitation before the secondaries kick in. But that could also be caused by another issue. I just don't know. Congrats on getting the porting done. Hopfully I'll be telling you all the same story after I'm finished with mine.

[Paul Workman]

Originally Posted by XfireZ51

There really isn't any difference between running the secondaries all the time or running on just the primaries. At any given RPM x MAP, the motor will need only so much fuel and air. Whether the fuel is being delivered by 1 or 2 injectors doesn't change anything. The total PW will be the same or at least should be. One of the advantages of no secondaries is not having to tune 4 VE and SA tables.

Yep! I didn't mean to imply that there would be a big increase in fuel resulting from running on all 16 - "closed loop" operation, and all that! And, to the extent my "instant mileage" readout goes, I couldn't really detect any significant difference there. Forget about trip mileage...Too much stop and go traffic, hills, and of course curves n a "few" WOT bursts - "...raises the level of ambiguity to the point of irrelevance!" (as a friend of mine likes to say) What I think really smoothed things out was the idle was consistent - around 700 (can't be sure as my tach reads a bit high), and the temp was consistently "mid scale" the whole time- stop and go, or cruising.

Anywayz...drivability (overall) is improved, no question. Now if I could just do something about those sport seats...I need the (later MY) ones Bob G has, methinks.

P.

[Kevin]

Originally Posted by XfireZ51

There really isn't any difference between running the secondaries all the time or running on just the primaries. At any given RPM x MAP, the motor will need only so much fuel and air. Whether the fuel is being delivered by 1 or 2 injectors doesn't change anything. The total PW will be the same or at least should be. One of the advantages of no secondaries is not having to tune 4 VE and SA tables.

the reason for the dual runner plenum design was to, according to designers, limit the amount of low end torque loss from the long runner design. so in theory there could have been a low end drop off of power.

[XfireZ51]

Originally Posted by Paul Workman

Yep! I didn't mean to imply that there would be a big increase in fuel resulting from running on all 16 - "closed loop" operation, and all that! .

No problem there. I have heard of some that believe running one injector will result in better mileage even tho the secondaries are removed. The motor is going to suck down so much air whether thru one runner or two. And maintining stoich will require x amount of fuel whether from one injector or two.

...What I think really smoothed things out was the idle was consistent - around 700 (can't be sure as my tach reads a bit high), and the temp was consistently "mid scale" the whole time- stop and go, or cruising.

P.

This could also be a function of new gaskets and better sealing overall. Particularly noticeable at high vacuum idle conditions. BTW, at idle only one injector is operating. Mine idles somewhere between 725-775.