Fast355

iTrader: (2)

Well that combination is equal to not half bad. Made a video when I went to pick-up chicken today for lunch. Runs very well now, with minimal changes to the calibration.

It was about 90* outside, the van had been sitting overnight. Fired right off and was driveable INSTANTLY. This is just driving around town, never went over 1/2 throttle or over 3,500ish rpm. A/C was blasting for the duration of the video. The road was much too crowded and there were way too many police cars on the road to really open it up. I have become a local favorite target with them, lol. Something about open cut-outs and WOT to 6,500 rpm at 1:00 AM that they didn't like.



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http://youtube.com/watch?v=lkEbHMHlYZM

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Me

BronYrAur

iTrader: (1)

Sounds like it runs great. I had actually been wondering lately why everyone has gone almost completely to dual plane manifolds when a couple years ago we always said TBI ran great with single planes because they still could provide the lowend grunt that you may lose with a carb. I think the Weiand 7525 was the manifold of choice back then, this one you've picked looks perfect, being a 2bbl manifold. Do you foresee any problems when it get colder out, as far has the plenum not being heated?

dimented24x7

iTrader: (2)

I drove thru last winter with an unheated manifold and a cold air intake. The drivability was actually quite good. The biggest problem I had was low RPM/high MAP leanout due to the fuel coming out of suspention since the airflow was too sluggish to carry it along. In the heat its not an issue because the fuel flashes to a vapor. When the manifold is below freezing, the fuel slugs on the floor of the intake causing the engine to lean out since the fuel is in blobs rather then mixed with the air. The other thing I noticed was sooting since the fuel isnt mixed as well. Also, you need LOTS of AE in cold weather. LOTS of it. Did I mention you need a lot?

With heated air from the engine compartment in the winter, a larger unheated manifold wont be much of an issue.

Dewey316

Glad to see you finaly came to dark side!

I've never had any drivability issues at all (granted I live in Oregon. 30* is as cold as it ever gets), in fact my car loves cold air. But, yes, it also likes its pump shot, with the huge plenum volume of the 4bbl single plane, my can't seem to get enough of the AE. I had a lot of trouble tuning the AE to work at low RPM's, as I changed my delta TPS and delta MAP to make it happy on shifts at high RPMs, it kept bogging down the low RPM changes. One you dial in the AE though, the single plane IMHO is the only way to go with TBI.

BronYrAur

iTrader: (1)

From what you (dimented and dewey) are saying, it definitely does sound like the way to go. I, on the other hand, was just removing a ton of AE today because of it bogging down rich with my 300-66 Holley. Mine never seemed to like the cold, always ran much rougher than I would have expected. I think that may have just been due to being overly rich. I finally messed with the idle today and got it running like its a stock motor, purring like a kitten at 550 RPM, not too bad with a ZZ4 cam.

I'm amazed at how well this car can idle and run like stock with this cam. What I said about AE was misleading though, I have to remove a ton now because I had it fairly dialed in and then upped the fuel pressure from stock to 21psi haha I suppose that will do it.

Dewey316

wow, you idle at 550. When I put my cam in, it did ok, but I bumped the idle to 675, it really purred there. With the new heads, I bumped it to 715, it really seems to like that. My motor likes a lot of timing, and a few extra revs at idle. I think all the added timing at idle, and off idle, might be part of why mine seems so mild mannered driving around.

BTW, I just got back from a 900 mile road trip, and averaged 32mpg! I am amazed at how effeciant you can make these 305 TBI combos, if you put in the effort and time to really tune them, and track all your data.

--John

BronYrAur

iTrader: (1)

Wow, that's awesome mileage, I haven't gotten that since I swapped gears and did headers ha. I really need to get my fuel tuned better I think and get my hiway mode stuff nailed down. I get bad mileage as it is.

You may want to look into some idle adjustments. I always had mine at about 700-750 after the cam and heads went in and it idled great, rumbled, loped a little. Today I wanted to try to see how low I could go, so I commanded 550, closed the throttle blades until the IAC was using about 10 steps to control the idle. Then I went with 26* timing in the idle area and made a flat spot around idle on my VE table. The VE had been learned to 128 but the overlap must have thrown it off because I took out about 10% fuel there and it runs like it did when it was stock, it pulls smooth right from idle with the clutch out, no sign of struggle, bogging, leanness, nothing. Oh yeah, and I messed with the prop gains a little bit, that seemed to smooth it out a bit too.