Jump to content
Ultimate Subaru Message Board

less power with a hitachi then with a carter-weber?


Recommended Posts

Hey everyone. If you have been following along ive just finished converting my car from the one barrel carter-weber to the two barrel hitachi. The hitachi runs a hell of a lot better with no hessitation off idle. And at cruising speeds when i accelerate to pass someone i can feel the secondary kick open and the car starts pulling harder than it did before. Only problem is that off idle its slower and more gutless than before. I mean i used to be able to spin a tire in the gravel with the one barrel and i cant even do that anymore. What gives? Im thinking maybe i need to play with the mixture. Would that be a safe assumption? Anything else i should check into? Would the fact that i dont have the duty solenoid anymore affect my off idle acceleration? Thanks for the help guys!

Link to comment
Share on other sites

I don't know the specific bores on those two carbs, but it's not uncommon to lose some performance off idle when you go with a one barrel to two barrel (or a two barrel to a four barrel). The reason is that the primary in the two barrel is smaller than the one barrel, so until the secondary opens up, you're actually running a smaller carb than with the one barrel.

 

You might want to make sure the accelerator pump is working. Usually you'll experience some hesitation if it's not.

Link to comment
Share on other sites

Im pretty sure the accerator pump is fine considering if its warmed up it doesnt hessitate at all. Even when its cold it barely does. I realized that the primary is smaller than the single barrel of my Carter weber but was hoping that that was not the only cause of my crappy power off line. But it might just be that. Do weber 32/36 carbs have bigger primarys? If so that might be next on my wish list. Well after a 5speed swap :brow:

Link to comment
Share on other sites

Yeah, the Primary in a Weber is bigger than the Secondary in the Hitachi, not a lot, but bigger.

 

If you do go the Weber swap, swap on an EA-82 carb style intake also. It has a larger port opening in it where the carb mounts. And in this case, bigger is better. I've done this twice now, and love it. Currently working on a how-to.

 

Another alternative, is to swap on a SPFI set-up. Better than the Weber, but involves doing some wiring. There's a write-up on that floating around on here, somewhere.

Link to comment
Share on other sites

Well just took the car for a spin today to get gas (its cold as hell up here and dont like it sitting with a low tank) and in the process got some STP fuel treatment for de-icing and general cleaning. Well i chirped the tires for the first time in a while. Im thinking the carb might have been a bit gunked from sitting for so long. It ran smooth as silk all the way back. IDK maybe im being optimistic but it seems to be running really good. I dont have the money to upgrade to a weber until summer anyways so i get some time to live with this carb for awhile. When and if i do swap carbs i think ill just stick with this manifold for general ease. I dont feel like pulling a manifold again even though it wasnt all that hard to do.

Link to comment
Share on other sites

you might want to get a can of Seafoam from a local autoparts store and pour some of that down the carb. Basically, you want to pull off the air filter housing and rev the engine a bit and start pouring slowly. You're engine will start to bog down but make sure it doesn't by keeping it revved up. It'll clea out any gunk thats trapped in the barrels. I'd recommend pouring 1/3 or the can down the carb, and the rest in the gas tank to help clean out the jets and whatnot inside the carb.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...