other options for vacuum...

[fantapants]

so curious and possibly dumb question.

what other options are there for getting vacuum to brake booster? The blacktop quads i have used on my 3s have a big built in vacuum chamber above the fuel rail, alos built in to the bottom manifold.

The manifold adaptor i have has no comunal chamber so to speak. Two of the throttles, 1 and 4, have a vacuum line attchment, but i planned on using those for the map sensor. How big a source does a booster need? like can i run these two small fittings to a laregr chamber that works for map sensor and booster or would that fuck up the map readings?

suggestions welcome

[julzy]

what i have done on my 16v quad conversion is,
Using an electric air pump.
There is a map sensor in the booster in which is run off a jaycar adjustable relay box.
When the map reading gets below a set Voltage aka, pressure,
the pump zaps on for a second and provides the lost vaccum.
Been running it for 2-3 months now with no problems,
it has a normal feel in the pedal and its an easy way to get a strong MAP signal while having good brakes.
hope it helps

[Golberg]

That's an awesome idea!

[Cerby86]

i'm running a set up where a vacuum port comes off three of the runners into a canister and the booster, fuel pressure and map all run off the cannister. I'm running an adaptronic though so i don't know how a standard ecu would go. Very good pedal feel though!

[Golberg]

You can't run a standard map ECU on a motor which didn't have quads to begin with anyway so it doesn't really matter. Well I guess technically you can, but its dumb idea.

[fantapants]

yeah im runnin adap..... more wandering if it would produce enough vacuum.... i only have two attachments, do you just drill and tap the others ?

[Cerby86]

I know of a lot of people have. Apparently the only time it isn't massively rich is at WOT.
And i have heard of a few people who run the standard ecu with a air fuel ratio piggyback and they seem to get good results though not as good as an aftermarket ecu obviously!
Oh and the adaptor manifold i bought had four massive ports welded into it but i had to block one off because the fwd water setup interfered with it.
One thing i noticed when i was pulling my motor down was that the vaccuum for the booster appeared to come off one runner!! So if you have two runners i would say you would be fine!!

[skit]

Mine setup is 16v engine, silvertop quads/T3 mount with a haltech.

I just used a series of tee pieces & small dia vac line to supply the fuel reg, MAP sensor & brake booster - the simplest way possible. Not very elegant but it works. Braking power is fine; no noticable change from standard.

I wasn't too concerned if the fuel metering accuracy decreased momentarily when braking (i.e. disrupted MAP signal), as I presume everything comes back into order basically instantly when you release the brake & crack the throttle again. Perhaps in autocross or gymkana events when you often use rapid throttle,brake,throttle applications the advantages of a vacuum manifold would be more warranted.

Vacuum manifolds are nice, but I don't think anyone has actually quantified the benefit they offer over a simple tee setup. Guess you could go for a drive with the laptop plugged in to monitor the MAP input reading when braking with both setups to evaluate the difference.

But just using a T3 style adaptor & quads you are already compromising all the benefits offered on a factory 20v setup (e.g. idle air bypass valve) so I guess it's back to the individual as to how perfectly you wish to replicate the factory setup.

Either way, it'll work.

Electric vacuum pump & signal switch is a great idea, I wondered about that myself.

[julzy]

The only reason i went the way i did,
was because i couldnt get a decent map signal off the manifold.
Now im running the T3 fittings for the map and blocked the others off.

[skit]

So you're using an external FPR instead of the factory vacuum one?