Edelbrock jet sizes

Automania · Post by **Automania** » Mon Dec 24, 2012 1:05 pm

Hi I've just been seeing what jets are in my carb and it has what appears to be 3x6 marked on them, but I can't seem to find what that relates to? Anyone any ideas? Cheers mike

Automania · Post by **Automania** » Mon Dec 24, 2012 1:11 pm

The other two seem to say 894? I'm trying to check if their suitable for a 4.6 or not. Cheers

Automania · Post by **Automania** » Wed Dec 26, 2012 5:59 pm

Ok I'm still having trouble finding the meaning of the numbers I found on my jets, so I'm going to get some new 65-47rods and .83 jets and hope that works.

JSF55 · Post by **JSF55** » Wed Dec 26, 2012 6:33 pm

http://www.edelbrock.com/automotive_new ... manual.pdf

sidecar · Post by **sidecar** » Wed Dec 26, 2012 7:07 pm

The jets in your carb are '3' series, the number will begin with 3.

The second two numbers are the jet size in thou of an inch. The standard primary jets for your carb are 386, in other words 86 thou in diameter.

The scondaries are 395. The jet sizes go up and down in 3 thou of an inch, eg, 83, 86, 89, 92......

Once jets go over 100 thou they become a '4' series jet, a 405 jet is 105 thou in diameter.

The rod numbers are also thou of an inch, a 62-52 rod has two diameters.

You can work out the area of any rod and any jet and subtract one from the other in order to get the ring shaped area that the fuel can flow through. Doing this means that you can compare any jet-rod combo with any other.

You can use the Eddy charts but I have found errors in them which does not help when trying to work out what needs to be done to your carb.

Oh a really good magnifying glass also helps, the number stamping on the jets is really bad!

Automania · Post by **Automania** » Wed Dec 26, 2012 7:54 pm

Tell me about it mate I'm on my second magnifying glass, one pair is 386 struggling to make out the second pair it looks like 894 but I can't find 94 as a jet size, I've tried measuring it and I'm getting about 0.090".

Automania · Post by **Automania** » Wed Dec 26, 2012 8:00 pm

Oh have you any ideas where I'd get some new ones from, I ordered some from road craft ages ago, they said they'd send them on when they got them, but they never arrived, reminds me I'll have to check if I got charged for them or not!

DaviesDJ · Post by **DaviesDJ** » Wed Dec 26, 2012 9:17 pm

Whatever jet size you go for - I can't recommend a wide band AFR sensor enough! What I thought was well jetted was pap, and I really noticed the difference in smoothness and power. For about 150 GBP plus postage, welded into the Y piece with well sealed headers - really brought my set up to life. Sure I'm telling you what you've already done as I am no authority:-) but just in case. I spend weeks musing on my jetting, and I've never looked back.

sidecar · Post by **sidecar** » Wed Dec 26, 2012 9:54 pm

Yep, what he said, its all guess work without a wideband AFR meter.

I think that its better than a session on a rolling road, you can spend as long as you like trying stuff out on a real road.

Repower sell jets and rods but their postage charge is a right rip off!

JRV8 or Muscle Manta might be able to help you get jets, rods and springs.

Automania · Post by **Automania** » Wed Dec 26, 2012 9:59 pm

Thanks guys, yep Im in motion with the wideband, not got one yet but got my eye on an innovate lc-1.

Who is repower? I've found them referred to in other posts but all google comes up with is roadcraft and some marine company.

I've tried manta on here too, and emailed real steel and a company in manchester ( forgot their name)

Cheers mike

DaviesDJ · Post by **DaviesDJ** » Wed Dec 26, 2012 10:46 pm

My sensor Is an AEM from EFI parts, a good package I thought

Automania · Post by **Automania** » Wed Dec 26, 2012 11:25 pm

DaviesDJ wrote:My sensor Is an AEM from EFI parts, a good package I thought

How do you find it for tuning? I read that for tuning you really need a data logger on a pc, I know the innovate comes with software and cable but does the aem? I've been reading up and apparently the lc-1 can be a bit temperamental?

sidecar · Post by **sidecar** » Thu Dec 27, 2012 6:08 am

I used an LC1to setup my carb, I did not use the data logging function though, I justed used a gauge.

I think you are right, Repower and Roadcraft are the same company.

DaviesDJ · Post by **DaviesDJ** » Thu Dec 27, 2012 11:42 am

I did not use the data logger, although i am sure the purist would, keeping a close eye on the gauge when crusing, part throttle and power runs is what i did, sustained WOT being the most tricky for me on the road as looking at the gauge repeatedly whistl hard acceleration is underway can be tricky;-). You will feel it get smoother and happier as you get it right. Dont go chasing absolutes - i go for low 12s power run and high 13s to low 14s part throttle cruse - this is a bit rich on cruse i know for economy, but its mainly a toyt and I run NOS so i like the false reasurrance of slightly rich;-).

Cobratone · Post by **Cobratone** » Thu Dec 27, 2012 3:19 pm

Firstly, listen to sidecarbod as there is no one I know who knows more about carb jetting than him, secondly, I had a few problems with the LC1 which was permanently installed in my cobra and have now changed to a Techedge unit. HTH