jmead Posted June 16, 2003 Share Posted June 16, 2003 Ok, well, I got my 60mm 240sx throttle body installed. Used aluminum spacer, already came with TPS and linkage, so it was basically just bolt-in. However, it seems there are some things that can no longer be connected. There is a hose comming out of the valve cover, it branches into 2 hoses, one goes to some sort of valve, and then into the old TB, and one just connects straight to the TB. My question is: What do I do with these hoses now that there aren't any provisions for them? Plug them up, leave them hanging, or possible install one of those valve cover breathers I've seen where the hose would come out? Also, the valve installed right behind the throttle body, what is it? I think its called the AIR regulator valve? What purpose does it have? Sorry about all the questions. And thanks for any help Quote Link to comment Share on other sites More sharing options...
CU Zcar Posted June 16, 2003 Share Posted June 16, 2003 Excerpt from my 1978 manual: The air regulator bypassses the throttle valve to control the quantity of air for increasing the engine idling speed when starting the engine at an underhood temperature of below 80degrees C (176degrees F). A bimetal and a heater are built into the air regulator. When the ignition switch is turned to the START position or engine running, electric current flows through the heater, and the bimetal, as it is heated by the heater, begins to move and closes the air passage in a few minutes. The air passage remains closed until the engine is stopped and the underhood air temperature drops to below 80degrees C (176degrees F). Here's a pic of that section, and the valve I think you're talking about. Dunno about the valve cover breather, I've seen plenty of people put little filters on that breather but I've noticed that my idle drops a little when I un-seal the engine (i.e. open the oil cap, dipstick, or valve cover breather). Quote Link to comment Share on other sites More sharing options...
zcarnut Posted June 17, 2003 Share Posted June 17, 2003 If you are still using the AFM then you need to connect the oil breather tube (the hose coming from the opening on top of valve cover) to a point between the AFM and the throttle body (like the rubber AFM boot). If you vent the breather to the atmosphere then you are introducing "false air" into the engine (via the PVC valve). "False air" is simply air that is not measured by the AFM and therefore not compensated for by the fuel injection ECU. Early 280Z's had a long oil breather tube which would reach all the way to a fitting on the AFM boot. I would locate one of these, for starters. The truth is that most people who use the 240SX throttle body are also making other modifications to the induction/FI system. One of these is to remove the AFM and use a MAP sensor. The MAP sensor does not measure air flow, hence "false air" is compensated for by the reduction in intake manifold vacuum. Another "problem" with the 240SX throttle body is that there is no provision for the idle rpm adjustment (!). You can use the mechanical stop screw for the throttle plate, but this results in a re-adjustment of the TPS switch and it also changes the characteristics of the ported distributor advance fitting (to that of a fitting that only sees intake manifold vacuum). How to connect the air regulator valve ("fast idle") is yet another issue with using the 240SX throttle body! Again, an aftermarket FI controller can perform this function or you can just not use the air regulator (I have seen plenty of people elect to do this). I hate to piss on your parade, but if you are keeping your induction/fuel system stock, then you are better off to use the Weber/TWM Big Throat (even though it is more expensive). Quote Link to comment Share on other sites More sharing options...
Guest 240hybrid Posted June 17, 2003 Share Posted June 17, 2003 I have a 75 280z motor with a 60mm throttle body from MSA without the rebreather for the valvecover. The motor runs like a champ without it, my locic is why would you want to rebreath fumes back into your motor when you can give it fresher air by eliminating the rebreather. I would just buy one of the k&N filters for the valve cover hole to keep stuff out and to filter some of the fumes on the way out of the motor ... http://www.zcarparts.com has them. Why would they make these filters if they were bad for your setup. They also sell a filter so you can eliminate the crankcase fume rebreather. just my $.02 Chase Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted June 17, 2003 Share Posted June 17, 2003 I hate to piss on your parade, but if you are keeping your induction/fuel system stock, then you are better off to use the Weber/TWM Big Throat (even though it is more expensive). The Weber throttle body is an excellent item. I have a 75 280z motor with a 60mm throttle body from MSA without the rebreather for the valvecover. The motor runs like a champ without it' date=' my locic is why would you want to rebreath fumes back into your motor when you can give it fresher air by eliminating the rebreather. I would just buy one of the k&N filters for the valve cover hole to keep stuff out and to filter some of the fumes on the way out of the motor ... [url']www.zcarparts.com[/url] has them. Why would they make these filters if they were bad for your setup. They also sell a filter so you can eliminate the crankcase fume rebreather. just my $.02Chase Why would they sell a breather if it wasn't the right thing to do? The answer seems obvious, so they can make money, and if it works for you that's fine. But the fact of the matter is the factory ECU was not designed to operate with large vacuum leaks, such as an open breather, and you may not get a satisfactory idle or off-idle response. Other than that, and your state's emissions concerns, I'm sure it's no big deal. Quote Link to comment Share on other sites More sharing options...
Guest 240hybrid Posted June 18, 2003 Share Posted June 18, 2003 I have a solid throttle body boot without any holes where the rebreather was (supplied with the 60MM throttle body) so thats not an issue for vaccum leaks. I cant be 100% sure about the valve cover filter changing the idle speed though, because the throttle positioning sensor and idle had to be reset after installation of the bigger throttle body. Just saying it can be setup this way, and I havent noticed any problems with it at all. Quote Link to comment Share on other sites More sharing options...
turbobluestreak Posted June 18, 2003 Share Posted June 18, 2003 for those breathers can't you just remove the PVC and add another breather on at the block? I've seen pics of it like that and plus it would be seprate from the motor and not leaking in air. But one thing buggs me about this idea and that is how will the crank vent I know it uses the vacum from the motor so will it naturally vent or will a vacum pump be required? Also a little off topic I going to get me a 300zx oil up and work on the set up for my motor and if it works then I'll be in the market for an RB20 cylinder head. Also I got my car back paint matilic blue and silver I'll post pics as soon and I can. tbs Quote Link to comment Share on other sites More sharing options...
lgoodson@pacbell.net Posted July 19, 2008 Share Posted July 19, 2008 Where,pray tell, do you get a Weber/TWM Big Throat TB? Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted July 19, 2008 Administrators Share Posted July 19, 2008 Where,pray tell, do you get a Weber/TWM Big Throat TB? This is an old moldy thread… So much has been learned and shared here since this thread started, you might want to give this thread linked below a read regarding all the power to be had by going to a big throat throttle body, which begs the question WHY get one, not so much WHERE to get one... http://forums.hybridz.org/showthread.php?t=119899 Good luck, Paul Quote Link to comment Share on other sites More sharing options...
lgoodson@pacbell.net Posted July 28, 2008 Share Posted July 28, 2008 Still don't know where to get one, but that was an interesting thread. Quote Link to comment Share on other sites More sharing options...
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