or you could just drive it a little softer so the turbos dont spool up too much? and cant a manual boost controller be had for about 50 bills?
my 2c
HE DONT WANT TO RUN THE SAME BOOST, !!Originally Posted by poombah
restricting the air that goes into the motor WILL lower the boost as the turbos cant draw as much air into the motor, thats why ahen you open up the air intake your motor will run more boost as it has more efficient airflow to the motor, so restricting the amount of air would be like putting it back to stabdard, the only thing is he dont have the factory snorkle to put it back to normal, the cardboard trick seems sensible as it can be varied wit the amount of air it will let thru via the size and amount of holes it has, by ppl saying it wont they are questioning the laws of mechanical engineering, more fuel + more air = more power.
my mate just wants to run less boost and doing it the cheapest way he can, this is a way that wont cost snything, i think that ppl are more into getting as much hp out of their car than reliability, which is wat the prev owner had in mind, sure the cardbord sounds crude and cheap, but so is the way that the air box has been modified to allow it to flow more air, but it does the trick.
there is nothing in line wit the wastegate actuators to bleed any boost out to truck them into running more boost, thats the prob.
as for the "i dont seem very confident" remark, i have as much knowledge or if not more than alot of ppl regarding the turbo motors, having owned quite a fewturbo cars, the last 1 being a 13bt s2 rx7 which had made 195rwkw and 13.1 sec 1/4 on 10psi wit only a few simple home made mods. the car owed me f**k all and the motor is to be fitted into my ra28, where it will have further more substantial mods as my budget is a bit better this time round.
the aim for this post was to ask for advice on HOW TO LOWER BOOST, it seems there are heaps of ppl that know how to raise it, some not knowing how to di it really safely at that, Or if any1 had a full standard air box or the front snorkle, which would RESTRICT the airflow thus allowing less boost to be run, my mate is on a very tight budget (no $ to spare) and i thought there should be some ppl who might be able to help, there have been some posts that are of help to stop the car hitting the boost cut, which is sorta wat i was aking for but removing the solinoid (which is actually called a hobbs pressure switch, for those who think i dont klnow much) will make for more boost,
thanks for the advice guys, but if restricting the airflow to back to how it came out of the factory is bad for the turbos, yet running such high boost is also detrimental the the life of the ceramic turbines causing them to fail, well wat in your eyes is good for them?? its plain and simple, he wants to run around 1bar of boost, the only way to do that is to undo wat is already done, restrict the air going into the motor, or restrict the air going out of the motor, the air going out of the motor will cost money, doing the air going into the motor wont unless he buys another airbox.
ke20 being restored and soon up for sale
or you could just drive it a little softer so the turbos dont spool up too much? and cant a manual boost controller be had for about 50 bills?
my 2c
"questioning the laws of mechanical engineering, more fuel + more air = more power" well i think thats more like a mixture of differnt engineering disiplines, namely chemistry.
Mate this cardboard idea is gay. All your going to do is make your turbos create more heat, strain them and reduce there life. Think about it, the turbos are trying to move a volume of air, this volume compared to the displacment volume of the engine is what determines boost.
example you have 2litre 1g, forcing 2lt of extra air in there is going to read 14.7psi.
By putting this restrictor infront of them they will need to move the same volume of air through a smaller hole. THis makes your turbos work much harder.
If you say that these boost gains are had from nothing more than opening up restriction in the intake then how is that going to cause premiture failure of the turbos. Its going to make them work less hard as they do not have to suck air through an as small restriction.
Where is this 'hobbs pressure swtich" connected?
you say here there is nothing to trick the actuators into running more boost but.....
but at the start you say this.....Originally Posted by kremsra28
are you contradicting what you have said????Originally Posted by kremsra28
the thing that controls boost is....the wastegates. you can run no form of airbox/airfilter/air inlet and drive around on...say 15psi...
OR
you can have standard airbox and standard filter and still have....15psi. with nothing else changed.
its the wastegate that controls the boost level. by having less restrictions just allows the turbo to draw air in easier, giving it a bit of a break. what POOMBAH is saying that at any given boost level, the less restrictions means the easier the boost will be produced. adding restrictions just strains the turbos, but they will make the same boost.
Originally Posted by The Witzl
There's no way a 1J will make 17psi with just a 3" exhaust & a pod filter, that's why everyone thinks there must be some sort of bleed valve in there. My 1J cressida has a 3" exhaust, opened up airbox with unifilter element plus a big arse front mount & only makes 11psi, so it sounds like there must be something wrong with your mates setup. Even if it had twin dumps it still shouldn't be that high.
What do you mean by boost control solenoid? 1Js do not have any sort of boost control solenoids standard, there should just be 2 very hard to see or reach hoses on each turbo, going from the compressor housing to the wastegate actuators. Maybe one or both of these are damaged or leaking?
If it's setup as standard it should be well under 14psi, so before you try to restrict the turbos check the wastegate lines & fix whatever is interfering with the boost signal to the wastegates.
Originally Posted by kremsra28
Dude if you cant figure out how to get the car to run stock boost by just farking off that solenoid and getting two bits of vacuum hose and hooking both actuators directly to the line on the compressor housings, then id say you know 5/8's of fuck all about turbo cars.
I've tried to give you some advice, I've been polite. but you know better.
You know what i want to say... "Your cardboard idea is completely, and utterly fucking stupid"
You gain fuck all more boost by removing factory airbox/filter and putting in a better flowing jobbie in my experience and ive worked on a few different turbo cars, maybe 1psi if your lucky. You can make boost slightly early and the turbos will work more efficiently but at the end of the day it makes such fark all difference that in this situation it is irrelevant.
If you put a restrictor in front of the turbos, they will still TRY and make the same boost, and they will work farking hard to do it, and as a by product of this you will probably fuck them if you leave it like that. Listen to what people are trying to tell you, or even better... take the car to a mechanic for gods sake.
Last edited by poombah; 30-05-2006 at 12:23 AM.
- Russ
'80 kp60 starlet
where's oldcorollas when you need him?
the first turbo car i wanted to experiment with had to be something simple, easy to work with and a toyota or as close as possible.
so came the G11 Charade Turbo, in all 4psi of full boost fury
airbox, no airbox, pod filter.. it's like driving in a cold day or a hot day.. fuck all difference and still make the same boost
as for your carboard trick i wanted to see if it'd spool any different by restricting the air intake. All it did was whine louder until full boost, and it still made full boost but lagged to get there.. lesson learned "it's not a vacuum cleaner"
as for lowering boost well u might be working with a purely mechanical item which explains how "home-made" and back-yarder works.. the 1JZ is a sophisticated machine which sees fuel-cut and boost-cut defenders... if restoring everything to factory and remove all after-market solenoids, boost controllers etc etc is still making 17 psi.. it's obvious something is wrong somewhere.. i agree that a dump pipe won't give a 5psi increase in boost. never seen it done b4, even a full dump-pipe off the exhaust side of the compressor wheel gained it 2psi max and that's more to do with the a bunch of other factors.
and those figures on your 13bt must be national records because 193 rwkw and 10psi don't sound right especially for a rotary..
okay my guess is your ECU is buggered or modified, the wastegate is stuffed if it's not responding to attention or the turbo has the "boost-mad" virus and can't be controlled..
Research has shown child in front seat causes accidents, accident in back seat causes child
Other than the well known wastegate, boost control CAN take the form of either an exhaust or intake restriction, and work very effecivly. Indeed, the stationary diesels that I work with atm have no form of boost control at all, other than that they're running at a constant speed, and even under full load do not suply enough fuel to cause overboost problems.
I remember as a dumbass apprentice I once accidentally left a rag jammed in the intake ducting of an RS Legacy (back when they were a flash car) and it very effectivly stopped boost from occuring!.
The problem with trying to control boost by using EXTRA restrictions etc, is that they can place loads on the shaft and bearings which they wern't designed to take (if you read my first post, I very deliberatly wrote AUTOMOTIVE turbos). On a turbo which has been designed to operate with a restricted intake, no problem, but given the fragility of the ct12a's on the 1j's, I'd seriously be looking at an alternative. As you'd know, there are alot of considerations when using a suck- thru set up with a turbo-carb, and allthough restricting the intake isn't quite as extreme as having the butterfly on the intake side, you'll find it will cause long term reliability issues, which IIRC is what this thread is all about?
What about using an gasket with a smaller hole in one of the exhaust joins (dumps to down pipe?) , I know its more work but at the end of the day, its correctling the ACTUAL problem you've got- which is the exhaust flowing too well and the wastegates unable to keep up. .
well come down here and have a look for yourself then, there is no bleed valves or any form of boost control other than wat the facxtory has put in place, and it too has me stuffed, even my mechanic is puzzled, i will take some pics if some 1 can host them, as for the cardboard trick, it did actually work by the way, and as for my rotor, get on ausrotary.com and have a look at some of the performance figures on there, my mate has a s4 that has 264rwkw on 12psi, and another has 250rwkw on the same in his s3. as for the national records, you obviously dont watch summernats dyno comp, as they have rules on boost restriction, its set to 15psi, and they have cars making over 1000hp at the wheels on 15psi, when my motor is rebuilt i will be looking at over 400rwkw wit a simple but effective mod that i dont know why more ppl dont do it. my new turbo will also help tho,Originally Posted by Vios-GT_07
as for the soarer prob, well who knows, we pissfarted around wit the cardboard and the aomunt of holes till it now peaks at around 15psi, but its only for a month or so till he can upgrade to a decent fmic, he is also considering getting the wastegate machned a little to try to help it flow better which shoul hopefully stop the boost from peaking so high, he is looking at borrowing some money to maybe get a single turbo conversion and ext gate.
i have upset a few ppl wit wat i have said in a few posts, but wat i have said is wat and how i feel at the time, and based upon my personal experiences and on basic mechanical engineering. every1 has had their own experiences and may belive in things differently to me which is life, and shit happens, some of the advice given by other ppl is true and would work but us not wat i was looking for or anything that would have helped me or my mate out, maybe if i could have tried to word things better to explain wat i was after it may have helped wit some of the advice i was given.
krem
ke20 being restored and soon up for sale
I can't believe that after the several extensive explanations of the way the cardboard restrictor will lower boost you still installed it.
Obviously your knowledge is far superior to ours.. I mean 1jz? not many of us can manage to lower the boost on them - they're a fickle and unreliable engine. almost as bad as the 2jz. much better off with a nice, sturdy, reliable rotor - none of these issues
LOL @ Draven
Wheres that thread on Ghetto backyarder car work? I can see this in there.
"OMG bro, that VL turbo totally beat your soarer ere.
Dont worry i'll pull out my cardboard boost controler and teach him"
Hope he fixes the problem soon without any damage.
Why doesnt he just drive carefully for a while? dont give it a boot and take it easy.
HZJ75, RS41, JZZ30
sorry i couldnt be bothered goin back and reading all this, but is it stoppin at 17psi ? or just freeboosting ?
yeap its a national recordOriginally Posted by kremsra28
end of story
Research has shown child in front seat causes accidents, accident in back seat causes child
so, on a serious note.
just to be sure to be sure, all there is a small peice of vacuum hose going straight to the actuator, with ABSOLUTELY nothign but a single, leak free peice of pipe?
MY RIDE, 2 Door LHD KE70 sedan with 1G HKS stroker: http://www.toymods.org.au/forums/showthread.php?t=51760
Punctuation is the difference between 'I helped my Uncle Jack off his horse' and 'I helped my uncle jack off his horse.'
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