quadrajet tuning for e85

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I hit a bit of a snag, or it hit me, in the form of a teenage driven honda accord cruise missile slammed into the right side front tire of the trans am. And it was driving so good with the jetting change too.

I increased the corvette's jet size to 81 from 76 to prepare for the e85 fill. I tried adding some 91% isopropyl and its still running OK. A difference in noxious smell is very instantly noticeable.
 
Originally Posted By: Shannow
bugger...


I was thinking about how many hours I've put into that thing. Probably around 500 about 2 days a month for the past 3 years.

At senior engineering consulting rate of 175/hr, what? Pushing 100k.

And I should have redone it to bitog standards right?...then double that.

You just can't get too caught up into a car.
 
I refuse to put a rate on my time at home, as I'm not getting paid for it.

Get the car back to "fun status".

I'm not adverse to a rustoleum paint job, and might have to do one on the Caprice at some stage.

Not sure I would on a matching numbers bandit T/A 'though.
 
I've been starting the vette every day. I can go off choke much sooner now, (i converted it to manual) so I think the primary jet increase has provided more fuel for the idle circuit. This was mentioned in the Lars Grimsrud paper. So I may not have to drill the idle pickup tube and/or the idle discharge hole. Encouraging.
 
I filled the Corvette with e85 yesterday. It still refuses to idle without holding the accelerator. Since I have a manual choke rigged I can pull the choke to the warm-up position and it idles fine. Otherwise it performs about the same as gasoline, but I haven't advanced the timing yet.

Serious modifications need to be made to an emissions era quadrajet to get it to idle on e85. You need very small drill bits to drill out the brass idle restriction tubes. Maybe I'll do it later this summer after I complete my projects on the trans am.
 
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Just took a little trip around the neighborhood. It feels faster. I'm spinning both tires more than it used to. Its idling acceptably now. I jacked up the idle screw. Mixture screws at 4 turns. The accelerator pump discharge holes may need to be enlarged.

Recap. Stock jets are 75. Installed are 81. Metering rods are 46p. Secondary rods are CH

No other mods right now. This is about 30 minutes work.
 
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The next step is to try some richer secondary metering rods. CH are the stock rods so I expect to get more power. I need to find my stash from when I started this a year ago.
 
Maybe you should try the DX metering rods? They were designed for the 80-81 Turbo Trans Am and are the biggest ones made for the Quadrajet.
 
the idle jets on a AFB are MUCH easier to get to. and you can drill the main jets IF ONLY IF you are very careful. and dont for get to block the bowel vent equalizer passage in the main body. so if you do any wild driving you dont dump gas into the other bowel.
 
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