FCR carb help

[megabob]

Hi all,
I've got a set of FCR carbs on my AE86 but the jetting and needle are wrong as i only get a good air/fuel ratio when over 4700RPM.
does anyone know what needle and main jet to use with the 4AGE engine.
thanks

[biggo]

I think jay from buddy parts used a set of 45's on his 16v. Try getting in touch with him by phone or PM sherlock on here.

But i have to say, using FCR carbs your not going to get a very broad rounge out of them over the entire rpm range.

Also do you have any pics?

[toyomad]

Hi there megabob , I am about to do this same conversion myself and after searching around for info I could only find a a guy in japan who had bought a set brand new , he supposedly used 165 main jets and it worked fine apparently , so hopefully this helps as that is what I will be trying for first up ,good luck with it and keep up the posts too let us know how you go!cheers for now , toyomad.

[megabob]

yeah i found the same guy. when translated its a little pigeon English but it does mention about the 165 main jet... good thing i bought a set of 165's

[kos!]

http://www.geocities.jp/koma_ae86/ae86_fcr1.htm

Picture number 12 basically says that the main jet should be 160-165, 160 for stock and 165 for more tuned engines.

[megabob]

But i have to say, using FCR carbs your not going to get a very broad rounge out of them over the entire rpm range.

Also do you have any pics?

yeah sure:
http://www.ae86drivingclub.com.au/dcimages/3/7/5/1/27397.jpg

[Schnickles]

I helped out with tuning jays fcr's its a long process not just main jet size but also air bleed jets, needle tapers, needle position and float height adjustment needs to be taken into account. But dont worry there is heaps of info on tuning them try these links i found them really helpful
http://www.keihin-us.com/tune.htm
http://www.factorypro.com/tech/carbkei.html

[JoshKE]

A little off topic, but do you have any photos of the manifold off the motor?

[megabob]

A little off topic, but do you have any photos of the manifold off the motor?

i can get some pics up later on today

[megabob]

I helped out with tuning jays fcr's its a long process not just main jet size but also air bleed jets, needle tapers, needle position and float height adjustment needs to be taken into account. But dont worry there is heaps of info on tuning them try these links i found them really helpful
http://www.keihin-us.com/tune.htm
http://www.factorypro.com/tech/carbkei.html


thanks, i've read quite a bit about tuning them but could you give me some figures for what parts aka needles, jets u used... i just need a good starting ground. i've worked on simple carbs like HIF44's which are super easy but i need a little starting help with this

[Schnickles]

just sent a pm, cheers

[af300e]

What jets (pilot/main and needle) are in your carbs now?

I'd start with 40 pilots, and 160 mains going by cylinder capacity (I've never tuned a set on a car, only bikes so the state of tune will be much lower for the 4age and will of course affect jet sizes.)

EDIT: I just read another post of yours that says you are lean at small openings, your pilot circuit sounds lean, let us know the jet sizes you have and we can go from there. When jetted correctly you should be able to go for WOT at any time without it shitting itself.

The main thing to remember is that the jets affect mixtures at throttle positions, not revs. Only the main air bleed which comes into affect at high rpm and WOT (over 6500rpm or more) is rev related.

When you next do a test run, load the motor at each throttle opening (1/4, 1/2, 3/4, 1/1 to start with) and whilst letting it rev out watch the mixtures. Poor jetting at any thottle opening will show up at higher revs moreso. If you can do that and let us know some of the figures that will help.

For the needle, I'd go for something that is lean in the straight section (fatter) for a leaner cruise and probably a reasonably gradual taper. You need the correct mains and pilots first though.

Float height for FCR's should be set to 9mm by the correct technique. It's rare to need to adjust it. Incorrect float height can fuck the low throttle openings and mask the jet effects so it's best to set and forget.
SET FLOAT HEIGHT BEFORE YOU DO ANYTHING

Jetting is as much correct driving technique for diagnosis as it is carb knowledge.

Are you in melbourne?

[hf86]

What fuel pump n fpr u using for the current setup??

I heard pumps like carter 4070 , etc will do.. where to get them??

Im about to do the same FCR conversion on my Hachi..