Ecotec Atom2 owners, throttle body leak issue

[Heywood-Yablowme]

I am in the process putting on my Harrop supercharger and was looking over the throttle body. Hmm..here is a fitting that looks like it was sawed off...



Wonder where it goes....yup,right into the motor.  



This open hole is allowing unmetered,unfiltered air into the motor all the time.Yes,all the time. This port is used to supply a vacume source to a car with an EVAP system,which our cars do not have.

Uncut throttle body evap tube..



However,when brammo chopped it off,they must not have realized that it is OPEN, directly to the intake,on the engine side of the throttle body,all the time.Not a good idea.
To seal it,you can use a #12 sheet metal screw (1/2" long) and a dab of rtv sealer,or if you don't want to disassemble the throttle body off the car,you could reach around the throttle body and dab a bit of rtv on the hole,working some in to the hole.There is no pressure here,only vacume,so it should hold fine.Don't run the car for 24hrs to let the rtv cure and it has to be room temperature or it won't cure properly(That's what the R-T in RTV stands for; room temperature vulcanizing)
I am using the screw method and a dab of rtv.

This open port will affect idle quality and anytime the throttle is closed,like deceleration,It is allowing in unfiltered,unmetered air,causing a lean condition.

Thanks again,brammo

All three of my cars have this brammo hack job.Chassis #39,103 and 121.

[positron]

Not so quick with the arrows there second hand Tonto.. Mine is intact like your second pic with a red plug/cap with a crimp clamp holding in place.

My car falls in the middle range, however it is odd that all three of yours have been done that way.

[Heywood-Yablowme]

You are looking at the wrong port.That big port with the red cap/clamp is on the supercharger body.

Not this port,which you can see from the top of the car: all mine have this port blocked off as well..





The OPEN port is on the front lower section of the throttle body, when the TB is mounted on the car,pointed right at the drivers back.Take a closer look...   You may need to use a mirror to actually see the port.

If you want to find this open port,start your car,and fish your hand up by the throtttle body,on the front lower side.You should find a hole that sucks your finger onto it.

All the LSJ's have this same throttle body,so unless you can see that long, thin brass tube sticking out,with a cap on it,chances are your port is OPEN.

[silver]

never knew 30hp would be so easy to find

[positron]

Ok.. I have to take my medicine on that one.. dang it.. Silver saw it.. 

If I'm looking at the right place this time.. mine has a stainless hex head bolt inserted where you suggest a screw.

[Heywood-Yablowme]

Ok,that is the correct place,and yes,yours is plugged. I wonder how many others are not plugged?  I am not saying they are ALL open..only my three,so far...

I doubt this is a horsepower robbing issue,more an idle,just off idle lean spot and on deceleration,which really is not a big deal as you can actually shut the injectors completely off during decel.    However,the air entering is unfiltered and unmetered,so it can affect throttle tip in and idle.Not to mention the potential of sucking in dirt,water etc..

My car always idled a few hundred rpms higher than I expected and tip in was poor(bucking,rough, etc)  which I attributed to the brammo tune..but most of the time,my foot was to the floor,so it never bothered me.

I'm not saying this is a panic situation..just a concern that Ecotec owners should check,especially if their off idle performance is sucky.

[Wmcmanus]

I'll have to check mine, but my guess it that it's not plugged.  I knew there was some reason I couldn't beat Darin around the track at Atom Fest II.  I demand a rematch! 

And a 5 lap lead on a 10 lap race. 

[Terry Kennedy]

[quote="MadMaxAtom and company"]
Ok,that is the correct place,and yes,yours is plugged. I wonder how many others are not plugged?  I am not saying they are ALL open..only my three,so far... [/quote]

Mine has a screw plugging the hole. I have a very early Atom (RAM285).

[silver]

Mine has hex bolt in it too.....easy to see if you don't have the firewall installed

[Heywood-Yablowme]

Hmm..well,I guess it is quite a random situation.My cars span a few chassis numbers and build dates.  Maybe the same guy built all three of my cars?     Well,if three have it unplugged,it does not hurt to do a visual to verify fitment of the plug in any Ecotec. They were all sawed off,so it seems only some weren't quite.."finished"...  

[DarthChicken]

Now we know why you have three atoms and why you were able to get such a good price on all 3 of them, LOL.

Seriously though, I found this when I was switching mine over to turbo.  A screw that was put in, that seemed very "unfactory" like.  If the factory tuned for it, leave it alone, if they didn't, fix it. 

Its like our catchcans.  The way things are hooked up, off boost (in vaccum) you're actually sucking in unmetered air through the catchcan filters (ie air sucking from outside, through the valve cover, through the PCV, and into the intake manifold).  Plug the filters, and you're car will go rich.  On boost, not an issue, as the PCV closes. 

[Heywood-Yablowme]

Yea,just think..Goldfinger ( )  was 1/2 price and I still paid more than a new Atom3.   I would not trade that car for....well maybe an Indy car. Happens to be one on Ebay right now.Too bad it is set up to run on alcohol ..Hell,I can buy that at about 1/12th the price it cost to build. That's a bargain.

Could you imagine one of those at an hpde?    :D


Cars are tuned for the PCV system and the catch can vacume losses,but not that open port.

If any Ecotec owner is experiencing a constant stumble off idle and hesitation,I would suggest checking for this hole in the side of your throttle body..

If not,carry on.. 

Damn..I can't WAIT to see how fast Max is going to be this year!!  All these issues I am finding..and I was having a BALL with it last year.

Got a good feeling about this year.

[Lane]

Here's what mine looks like:

[Sagen]

For those keeping score at home, mine did /not/ have this hole plugged.  My chassis was in the first third of the Brammo production run.

I found this when pulling throttle body off to install the Harrop.