2.8 FI to Carb

[FieroFanatic]

Don't forget a bypass type adjustable fuel pressure regulator if you have an electric fuel pump.

[bruce farris]

Thanks; fuel press 5 psi +/- .has anyone blocked off the hotair passage and run a carb on the street with edel intake...

[Arns85GT]

I don't know about the hot air passage. Is that the one that runs from #4? I simply ported so that the air would go by it and left it open

Anyway, I have the 390 cfm Holley on the Edelbrock intake. Tricky to meter due to the small engine, but I got it working well after alot of experimenting and research.

Arn

[bruce farris]

Yes ,the passage from #3 to #4, which causes a hot plenum floor inturn vaporizing any fuel puds and promoting better lower end in theory...but ........hurts top end stuff ,, just wondering if anyone had blocked it off without regrets.
I,d be interested to know what you jetted the 390 to as a good starting point for my project...thx..

[Arns85GT]

here is the 390 setup that works on the 2.8

This is my setup so far, however I do not have the secondary spring fine tuned yet.

#512 primary jets
#52 secondary jets
#31 shooter with orange cam center re-drilled for 1/2 shot
Light yellow secondary spring
8.5 power valve (my vacuum at idle is 16 and I need a richer power valve)

Arn

[bruce farris]

Thanks Arn ;I'll try the #512 primary ,cam and power valve .I'm using a 500 2 barrel . I've had sucess using large throttle plates (over sized carbs), that's contrary to popular belief...but works quite well ..

[Arns85GT]

Thanks Arn ;I'll try the #512 primary ,cam and power valve .I'm using a 500 2 barrel . I've had sucess using large throttle plates (over sized carbs), that's contrary to popular belief...but works quite well ..

Bruce, when I had the 2 barrel I was using #62 primary. #512 would have been too lean. I would set the power valve proportional to your idle vacuum. FYI

Arn

[bruce farris]

lean's not a good place to start ...thanks for the correction.

[FieroFanatic]

I'm about to swap a carb setup for the F.I. in my fiero. Does anyone happen to have pictures of this setup? Longshot...

[Arns85GT]

as requested

Hope these help. I call mine my "baby Big Block"

Arn

[FieroFanatic]

Hey, great minds think alike! ( or is that sick minds..) I sent you a message

[bruce farris]

Carb.nuts

Great pics Arn..I'll have some too in months to come and hopfully a DYNO pull to boot .

[Arns85GT]

Here's a couple to compare

I did a couple of whp dyno's as a way to tune the engine. There was alot of finagling to get the carb dialled in.

You'll see on my earlier post the first one showed some real problems with my primaries and secondaries, as well as a bad bogg.

The second one cured most of the primary secondary metering, but I did not resolve the accellerator pump problem which was still showing up as a definite bog.

The bog has since been resolved and I'll be dyno'ing it again this season with some changes. The eventual goal is just 140 whp. Not alot, but, good for my purposes.

Arn

[bruce farris]

Arn; What kind of torque did you see?? I like to see torque #'s too ,it gives a more overall picture of drivability. What does the Edelbrock intake ,with small runners to one bank , do to overall performance? Does anyone but Edelbrock have an opinion ?

[Arns85GT]

Bruce, the torque was pretty much bang on 140 ftlbs from 3,000 to 5,000 at the wheels. My compression is not great or it would be higher. The compression shows @ about 125 across the cylinders. When I modified the engine I did not give it new rings. I should have.

Arn