FCR motorcyle carb help

[D-limo]

Thought here would be a good place to get the lowdown on fitting Keihin FCR's a to car engines.

Basically want to fit some 41mm's to a Nissan FJ20.

Have been informed that GSXR types are best for car engine applications. Have my eye on a set meant for a 750cc which I would need to jump on in the next few days. Will these flow as well an 1100cc set?

Also, a carb expert has told me the fuel and air correction ports are too small in stock form so they run pretty lean unless alot of time is spent on drilling them out. He also mentioned 'car specific' FCR's exist. Can anyone confirm? Keihin USA has denied this.

Is there a workshop in Aus that has experience in fitting FCR's to car engines?

[Rice86]

im sure there is, but you would have to be asking a different crowd of car enthusiast as this forum is very limited when it comes to Carbing a EFI engines.. maybe speak to your Carb expert again for more info, if he is a carb expert, shouldn't be hard for him to figure out what needs to be done to get it running

or hit up a performance shop that is very knowledgeable with carb performance, think like a bogan.. hot rods, V8 na with carbs etc..

[LittleRedSpirit]

Yeah but v8 people are going to know about downdraught systems probably, not so much on the fcr flat slide side draught high tech side.

I thought there was fcr jetting in the trd bible, couldn't you use that as a starting point? You just need to learn to read Japanese.

Its got to be possible, Ive seen some amazing setups with fcrs in an ae86 on youtube.

Id be talking to motorcycle tuners and seeing what they say.

I always thought that not a whole lot of engines came stock with fcrs, as the CV type gives better economy and almost the same response. Its only when you get to high rpm racing applications where idle speed and economy is not a concern that people go to fcrs for the less turbulent airstream and potentially higher cfm per mm of throat size.

From what I could find the biggest they come in a matched set of 4 was 41mm. This should be fine on a 4age with the right jetting/modifications. They are generally sold as a kit for retrofitting to superbikes that came with the CV carbs.

I know there is a manifold from RS chita for them, perhaps if you can get some engrish out of rs chita you might be able to gets some more information, or find a japanese person to email them and translate.

[D-limo]

Urgent query's.

Auction on the 41's I want finishes in 19 hours. Just found out they are downdraught type. Am I better off sidedraught or downdraught? Or will both work well when setup correctly?

can anyone confidently tell if these are sidedraught or downdraught?

http://www.ae86drivingclub.com.au/dcimages/2/1/5/7/313610.jpg