CARB TUNING:All carb "Experts" leave your "Tuning" secrets here!Then we'll all be able to tune'em

**gtfordified** · 04-25-2002, 11:01 PM

Allrite every one !!!Lets here your method of tuning Holley carbs!Cruise Vacume ???
Plug readings by miss cleo ???Power valve swaps...."Jet" tuning ,Every thing!Spill it!
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**Hottarod** · 04-26-2002, 12:12 AM

I wish I knew. I've been fighting carb problems for almost a year now. It helps to be good at generating mathematical permutations so you can try every conceivable shooter, pump cam, jet configuration and power valve made in your futile attempts at trying to get it to run right.

I've done a total reset on mine twice and gone completely back to the out of the box set up and started over. That hasn't really helped much but I felt better afterwards, LOL.

**ValveTubeHead** · 04-26-2002, 01:46 AM

First...
buy an edelbrock/carter afb, so you can drive everywhere you need to go without gripe... then round up your holleys' jets, gaskets, a timing light, vacuum meter, notebook, a halon fire extinguisher and a drag strip. Try EVERYTHING until you squeeze 5-10 more mph out of a 1/4mile for the day. Put your trusty carter back on and drive home...jobwelldone

Countless books and magazine articles discuss this topic in lengthy detail and photos. Every air pump's different, a lot of trial and error seems to be the norm.

**DynoTom** · 04-26-2002, 02:10 AM

I have a system that alot of racers use for carb jetting that gets the jetting as close to perfect as can be.

It uses EGT sensors and it can determine how rich or lean the carb is by the exhaust gas temps.

I'm going to use a Perceys EGT sensor kit with two probes on my 408 Winsor in the Falcon.

You should always measure the leanest cylinder(s) on your engine with the EGT device.

To use this method you really have to use a EGT sensor device that stores the readings so you don't have to read a analog gauge at WOT.

It all has to do with the gas temps at the header pipe.

I good yet safe burn temp is 1450* so if your temps are 1450* plus or closer to 1500* your too lean and can melt some pistons and also hurt the rings and valves.

It goes the same way if your readings are colder than 1450* you are too rich,keep in mind more fuel charge will cool the EGT readings.

For every jet size you go down or up it will change the temp about 20*,you have to use high quality jets to get this type of accurate readings.

Next time your in the pits at the track I'll bet 99.9% of the real fast cars have EGT storage devices on board.

It's a cool way to get it just right.

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**CougarKid** · 04-26-2002, 03:09 AM

EGT's sound good. Any one using o2 sensors? Which is preferable?
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**a1320tom** · 04-26-2002, 11:21 AM

I have been using an O2 sensor and been real pleased with it. I mount the LED box on the dash, so I can see the A/F mixture at any point during the run. Downside is the sensor is in one header, so you only get an average reading for one bank.

**oldmustangjunkie** · 04-26-2002, 11:30 AM

Where did you get the A/F meter a1320tom? I found one at nedyno.com and it only works at WOT.
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**a1320tom** · 04-26-2002, 12:41 PM

oldmustangjunkie,
I picked it up at Napa. Can't remember the brand. I had to have a bung welded on the header tube and the unit came with an LED display and enough cable to run it through the firewall. The LEDs are red, yellow and green as it goes up the scale from lean to richer. So I can make a jet change, see the mixture at idle, then at WOT on the track I just glance at the LED display and verify that the mixture holds where I want it.

**dragman64** · 04-26-2002, 02:35 PM

I got this one for about $30 from Summit. Just need to weld the bung in and get a O2 sensor from the parts store. It does the job.
http://www.nordskogperformance.com/index.html .
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**qtrhors** · 04-26-2002, 03:12 PM

get a holley catalog with all the specs for the carbs they make....get a how to book on holley carbs and get a vacuum gauge. Now you can start [img]/phpBB/images/smiles/icon_smile.gif[/img] Learn to read the plugs. Most holleys have power valves that take at least 6.5 inches vacuum or more to close out of the box...this is usually the 1st thing that has to be changed with healthy combos that have little vacuum at idle.
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