Which one is the biggest? Lol
CK5
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Ran a series of tests today and discovered something... i am not getting much if any vacuum off the port on my fitech unit that i had my timing connected to...
Like i can unhook it nothing changes on engine idle, dont hear sucking, i can plug it with my finger i dont feel anything... i checked my timing connected to ut i was sitting at 24-26ish around 700ish rpm.
Switched to a manifold vacuum and its sitting at 35-36 advance at idle...
Seriously if this fitech is defective and it has been my issue from the start i may freak out...
Connected to manifold my advance is 35 at 700ish and 54 at 3000rpm.
Like i can unhook it nothing changes on engine idle, dont hear sucking, i can plug it with my finger i dont feel anything... i checked my timing connected to ut i was sitting at 24-26ish around 700ish rpm.
Switched to a manifold vacuum and its sitting at 35-36 advance at idle...
Seriously if this fitech is defective and it has been my issue from the start i may freak out...
Connected to manifold my advance is 35 at 700ish and 54 at 3000rpm.
Did some asking on thr fitech forum and found out the port i had my distributor hooked to is metered and only has vacuum when the butterfly is open. So if my foot isnt on the gas no vacuum.....cant wait for another day in the 90s where i can test this thing...
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That'll do it
Whats absolutely stupid is this is where they said to connect it. I am a stickler for following instructions exactly how they are printed.
I also feel a little dumb because i was unaware that there was a manifold port on the fitech and i added a t to the manifold. I could have just swapped ports.... ugghh
so you had it on the wrong port? I use that 3/16” vacuum port on the cars I’ve done (without timing control) and it’s been fine.
No it was on the correct port. With a big cam you need to do manifold vs metered vacuum. According to fitech instructions they have you put it on a metered port. That port get zero vacuum until the butterflies open.
I just read a few articles and it sounds like unless you need emissions or have a stock engine you need to be running off a direct manifold port vs metered
I just read a few articles and it sounds like unless you need emissions or have a stock engine you need to be running off a direct manifold port vs metered
Aren’t the butterflies open with any throttle? My buddies ZZ502 runs awesome on that port.
I guess that depends on where his IAC steps are set, and they said that its variable based off throttle position. Also how big of a cam he's running.
When at lights or in park and your foot is off the gas and your tps reads 0 there is literally zero vacuum off that port.
When at lights or in park and your foot is off the gas and your tps reads 0 there is literally zero vacuum off that port.
You heard the cam at B.B., it’s big but I don’t know the specs off hand.
If you’re having timing issues you likely need distributor work or you need to adjust your base timing.
Lol man i think you have missed about 15 pages of this thread.
We are trying to figure out why this thing runs hot since adding a/c and fitech.
The reason we are looking at timing is i have upgraded literally everything on my cooling system and adjusted my afrs.
If its not advanced enough at idle it will cause it to run hot.
I dont have a timing issue i have a heat issue that may have been caused by not using a manifold vacuum.
Here is a great article about manifold vs ported/metered vacuum for anyone interested.
http://chevellestuff.net/tech/articles/vacuum/port_or_manifold.htm
@skunked
We are trying to figure out why this thing runs hot since adding a/c and fitech.
The reason we are looking at timing is i have upgraded literally everything on my cooling system and adjusted my afrs.
If its not advanced enough at idle it will cause it to run hot.
I dont have a timing issue i have a heat issue that may have been caused by not using a manifold vacuum.
Here is a great article about manifold vs ported/metered vacuum for anyone interested.
http://chevellestuff.net/tech/articles/vacuum/port_or_manifold.htm
@skunked
Yeah, you had it on the non-manifold, aka emissions crap, port. I think they tell you to put it there because it's the safe option in case customers need it for emissions. Really whether or not it works well on that metered port probably depends on how your distributor is set up.
Like I said before, my 66 doesn't even have a metered port. It was added later to carbs as emissions standards got stiffer.
I'm sure some vehicles can run fine that way.
Like I said before, my 66 doesn't even have a metered port. It was added later to carbs as emissions standards got stiffer.
I'm sure some vehicles can run fine that way.
Yup i agree i think most run fine with it.
I think its luck of the draw/build.
I think its luck of the draw/build.
actually we talked about your timing last year, I asked if you're timing was set too far retarded. Remember?
Yup. Turns out with or without being connected to that port on fitech i was sitting at 24 advanced.
Now when i connect to vacuum its sitting at 35 advanced at 700ish rpm. And still 24 when not connected to vacuum
Now when i connect to vacuum its sitting at 35 advanced at 700ish rpm. And still 24 when not connected to vacuum
I still think you should compare it to a TBI truck at idle.
I will as soon as i have access to it
so purely out of curiosity i am wondering if any of you guys know the tube size for a 70s 454 factory brass/copper 4 core radiator ?
also you guys going to blazer bash, our group may be losing a couple that was sharing a condo with our group so we might have an extra room if someone is looking for a place for BB18. Its a three bedroom condo we would be splitting 3 ways @72gmck5 myself and our gals we be your roomies.
@blazinzuk can speak to how nice the place is
also you guys going to blazer bash, our group may be losing a couple that was sharing a condo with our group so we might have an extra room if someone is looking for a place for BB18. Its a three bedroom condo we would be splitting 3 ways @72gmck5 myself and our gals we be your roomies.
@blazinzuk can speak to how nice the place is
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