spanners Posted January 19, 2011 Share Posted January 19, 2011 So I am using BT 20v quads on a beams motor. I dont really wanna run a map sensor but am going to, hopefully it makes tuning easier. What I wanted to know is whether i should us a standard 20v one or if an aftermarket one is going to be any better. If the toyota one is ok, does anybody have one for sales? I intend to run both the map and the vac line to the brake booster off the two small dia outlets on the TBs for cyls 1 and 4. Is this going to be sufficient or am I going to have to drill into all of then and run like a 5mm ID line across the whole lot? I dont want to drill into TBs or into manifold if its not needed. Thanks Quote Link to comment Share on other sites More sharing options...
mikuni Posted January 19, 2011 Share Posted January 19, 2011 I assume you'll be using an aftermarket ecu, which will have a map sensor built in. I can't reall yhelp with how to get vacuum, because I haven't been able to get any on my throttle setup but there are ports off the throttles that you might be able to use. I have small tubes welded to the intake runners, to an accumulator and it has no vacuum anywhere off idle. I guess it might be better with a pelnum/sealed air box. Quote Link to comment Share on other sites More sharing options...
spanners Posted January 19, 2011 Author Share Posted January 19, 2011 Hmm. Fuck. Brake booster might suck then! Quote Link to comment Share on other sites More sharing options...
mikuni Posted January 19, 2011 Share Posted January 19, 2011 With closed throttles you still get normal vacuum, enough to run a brake booster, it just falls away as soon as you open the throttles. In a car like a kp you could get away with no booster though, depending on the brake setup/system you are running. I don't use one on my Chevette and I think its fine, but some others who have driven it disagree. Quote Link to comment Share on other sites More sharing options...
Valiant Posted January 19, 2011 Share Posted January 19, 2011 You should have vacuum, all cars with side draughts do. Personaly I would try and join all the runners together or you will get a pulse signal to your map sensor as the intake valve opens and closes. Quote Link to comment Share on other sites More sharing options...
kpr Posted January 19, 2011 Share Posted January 19, 2011 booster will be fine. i run mine off both outside vac points on top of the throttles. cant come off those ones on the bottom of throttles. for map signal, best weld/tap a line off each runner in manifold. then will need to damper the signal, using a chamber/damper of some sort. do worry too much about lag on map signal with the dampering , can be tuned around. also don't run the booster off the same point, map needs to be on its own. fuel pressure reg, can just run a flat pressure so don't need vac signal but, your going to run into the usual problem, with itb's. you will run out of vac somewhere after 50% throttle. so need tps to take over from there its usually whole lot easyer to tune in tps only. i run my 4a like this Quote Link to comment Share on other sites More sharing options...
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