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celicamad
Forums Junkie

Location:
newcastle
Registered:
June 2002

Re: Found Flow Limit on 1JZ Turbos

Fri, 29 August 2003 13:52

wastegate
to quote yojimbo

Quote:

I have no problem controlling boost up to 1 bar (creeps and settles at nearly 1.1) , however when set at more than that wastegate creep starts a runanway trian with no hope of controlling boost below about 1.4 bar.

Andy's 1j does the same, but worse, specs are similar to yours Wastegate. Good to hear its common.

I'm with you on the turbos, not ever gunna take em off again.

Matt

both of these cars run stock turbos and my car did exactly the same thing .i developed the boost controller to stop this and it works

Quote:

Do not take this the wrong way but you are starting to stary off the path of this thread. It's just that you are marketing a product that is not a solution nor is a boost control problem. I'm sure your boost control works very well but it wouldn't help someone with my problem nor a simliar problem.

definatley not taken the wrong way but it will solve a boost controll problem and that is what yo jimbo has .if he sets his boost at 1.1 bar the boost controller can controll it ....no wastegate issue here . if the wasgate can controll boost to 1.1 bar then it works fine anything else is a controller issue .some of my early controller designs did the same thing

im not just trying to market my product it will fix matts problem and considering the topic is controlling boost and he has the same problem im certainly not off the topic

however in your case the big increase in flow has found the limit to factory wastegate. even with no controller in place boost is high .( you already know this).no controller can lower the boost more than this

running a seperate wastegate dump will allow a lot more flow through the wastegate .even though your running twin 2.5 inch dumps .the wastegate air still is restricted . considering off the shelf dump pipes are avialabe (see hpi magazine ) they might be worth a shot

ther may however be another cause

i have encountered this problem before .your assuming that the wastegate is fully open !!.

i have seen now two sets of 1j turbos where the rear turbo wastegate is sticky and wont fully open .the actual problem was in the actuator .think of how they work.

A given amount of pressure is placed on a diaphram and this pushes the actuator shaft a given distance . if the action of the wastegate is restricted .than it wont open as far . however in most cases the actuator diaphram is leaking therefore bleeding off boost and not opening the wastegate as far

it was quite simple to test we applied a regulated 10 psi to the wastegate on a bench still attached to a turbo to see how far it opened at 9 psi the front turbo was fully open however the rear when to approx 14 psi .at 9psi it was just over half way open . new actuator problem fixed .although this is not exactly the same as an in car situation it did however prove that one actuator was definatley rooted .

now the interesting part about this is the most famous 1j turbo for shitting itself is the rear turbo and i have only ever seen rear actuators die . perhaps both problems are a heat related issue ???

as i said this may not be your prob but its not hard to test or maybe even try a different actuator to be sure

it would be interesting to see if you put it on a dyno monitored duty cycle and mixtures and checked boost with a calibrated gauge( not uncommon for a guage to be out 2 psi)to see if there is really any problem .

The stock injectors are good for around 250 rwkw ( average dyno).so if boost maxs out at 1.4 bar (for eg) than you might not exceed this . your more than likley pushing the limits of factory ecu but not exceeding them if this is the case .

the hybrids may well flow much more than this but they would be the first pair ive ever seen do it .the last set of Good hybrids i saw made 1.4 bar( no controller) and ran 92 % duty cycle .by slightly retarding the timing ( at the crank angle ).They where able to keeep boost at 1.2- 1.3 bar and 86% duty cycle .

and yes he ran twin dumps free flow systems

yeah sure he really needs to go aftermarket ECU but currently hes more than happy with the result and cant get traction anyway

i just suggesting that although you have increased the boost by removing the restriction .why not try it on a dyno and see how far it will go .The problem may not be as bad as you think

as far as if my controllers will solve matts problem on stock turbos im happy to prove it .Matt(yojimbo) and i have almost identical mods and i can control anywhere between 1 and 2 bar same boost all gears

[Updated on: Fri, 29 August 2003 13:56]

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