Thread: BOOST BOXES

Originally Posted by Alex 110

did I mention crap road tyres?

Space saver spares all round I say.

I read a few posts about the boost boxes on here and got some advice from someone off here , sorry forgoten the name , about a home made box . This box monitored the voltage output from the map sensor and when it got high it changed to a preset value below the max boost . So I am lead to believe thats the way they all work .
At the time I was considering another way to do it but have not had time to get back to it ( or think it through properly ) . The map gets a 5 volt signal from the ecu and runs across a variable resistor , the map sensor , that I think reduces the value with pressure . Less resistance = more voltage . I found a SA web site that listed the various pressures and voltages of the map sensor , this is roughly linear .
If I was planning to bump up the boost by 5 psi say I was going to work out the resistance at 15 psi less the resistance at 20 psi and then add it to the output signal to the ecu .

At low boost as the resistance is high anyway a small increase would ( hopefully ) hae a small impact on the engine but as the resistance decreased with boost the extra fixed resistor would have more impact and gradually be offset by 5 psi . With a slightly remaped ecu I figure the ecu will be putting in more fuel than standard anyway so should be ok with the extra unknown boost . If I am correct it gets capped at a low value anyway with a boost box .

By doing it this way the overboost protection would still be active , just at a higher setting , as opposed to the signal being capped and therefore unknow after that .

Anyone looked into this , see a major flaw in this ?

Chris

used to mkae up a variable boost cutoff using pots for the Toyota Starlet engines, they used a MAP sensor and it went inline to the sensor and you could adjust the boost cutoff up and down, but not remove it entirely, that is safer than disabling the cutoff in my opinion.

my td5 90 will spin 1st into 2nd from a rolling start with 235 gg tyres.

Originally Posted by Benny_IIA

my td5 90 will spin 1st into 2nd from a rolling start with 235 gg tyres.

Nice, so what set up are you running?

bronson

manual ?
manual is easy to spin, you can dump the clutch.
i guess you could slam from neutral into drive in an auto with some throttle on, but i ain't gunna try it. i wanna drive my car again tomorrow

Originally Posted by Rosscoe68

manual ?
manual is easy to spin, you can dump the clutch.
i guess you could slam from neutral into drive in an auto with some throttle on, but i ain't gunna try it. i wanna drive my car again tomorrow

Its a manual and no dumping the clutch.

Justs needs to be rolling in 1st gear and put the foot down and it will spin the wheels then smooth change into 2nd and give it a boot and tc light comes on again.

Its running a Hybrid Turbo technics Stage 3 vnt, Custom td5 inside maping, allisport inter-cooler, IRB dual boost box etc. Soon to have upgraded airbox fitted.

Hello,
I did make my own boost box rather volt switch, it switches at a pre-set voltage then back again works great both for MAP and MAF never a over boost, you can tune it to what suits you.
I did buy one from the uk and on their ones they use a bleed off of volts for the WHOLE range not just when it needs to be switched, a bit like the MAF bypass it gives poor performance on the whole range not when you need it right at the top, they do charge quite a bit for them the money would be better spent Pxssing it on the wall.
I can give anyone the info on how to do it.
Ian