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Over boosting


Locko90

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Screenshot_2019-11-24-10-28-30.thumb.png.6450a9b52dae81e4c4c6ec6b0b1774b0.png

 

A snapshot from a recent outing. Looks like the Turbosmart IWG actuator is misbehaving and allowing boost to exceed commanded levels of a recent tune. A common thing it seems from comments made previously by @JETURBO. Have NFI what spring is in there, maybe a 8-9lb spring would help? or back to a Garrett actuator?

GT3576/billet wheel has had flapper mod done, apparently.

Went out for a spin today and max boost was 18.8 (U98). AIT's were stable around 38-41C despite being a pretty warm day, so the CAI & Plaz 800 is doing it's job.

Question is, are these obd2 readings accurate as accel reading seems a bit odd.

 

Motor gets heat soaked after 6-8 pulls as standard 91C thermostat and high speed fans come on at over 100C. Prolly should go the 82C stat with the lower thermo fan activation setting in the tune for the tropics as per @BJC, although there was a bit of past debate, as I recall, over the value of doing this.

I hope this would be a quick and inexpensive job for the tuna to do?

No idea what the STFT1 reading means except near 0 is good at idle.

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My bad. Thanks for the heads up @El Andrew I did look at the conversion a while ago, but clearly that info went through to the keeper.

My simple error could be a good thing that car may not be over boosting, I'm certain it is way over 10 PSI though. 

Car was previously up to 21 PSI on dyno and recently retuned to 17, so hence my apprehension.

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Firstly watched a few youtube vids. Bought cheap ELM327 reader on Ebay, downloaded and opened torque app on phone, turned on wifi to pair etc etc. 

Will upgrade to Torque pro soon to access more info such as trans temp. 

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So your post has got me thinking.

Could I possibly get a after market boost controller like the gfb 3.0 and just set the over boost value too 10psi then it would in theory stop the turbo spooling past 10 psi effectively stoping my boost cut issuse?

On a side note I would rather have the car running at about 12 psi, is there any possible way of disabling the ecu boost cut or tricking the ecu into thinking it's running lower psi?

How does the ecu measure boost? Could I possibly disconnect a sensor so the ecu can't read boost or will the cause a running issue?

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There is no shortcutting this. The ECU, with its boost and map pressure sensors, is already effectively an electronic boost controller.

If you had a way to trick the ECU you would be adding boost without the required fuel and timing map changes. This will very likely break your motor.

The only safe way to add boost is to get the car properly tuned which will update all if the required maps in the ECU.

While you can do this on stock hardware, it would make sense to also make any supporting hardware changes (especially exhaust and injectors) you are planning at the same time, so you don't have to pay for another tune later.

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Step one, stop driving your car until you find out what injectors you have.

10psi on a stock fuel system is out of fuel easily.

my ba stock ute hit 8 psi before the afr's started heading for the moon.

The injector near the thermostat housing should be easy to see, just take a photo of it and if there is no numbers maybe post it here for Identification.

If you have aftermarket injectors then you have to have some sort of tune

 

Your turbosmart wastegate actuator proberly has a 7.5psi spring in it

if the pre-load is tighter than required, it will hold more boost

as you have a free flowing exhaust its not uncommon to have your boost become uncontrollable.


if you have your boost reference going directly into your actuator, this is your min boost - you cannot install a boost controller to make less boost than this.

either fix you exhaust so it is more stock, or go get your wast-gate flap ported, or an external gate setup.

These cars require SFA modifications to send them into over-boost territory.

all my turbo barras run external wastegates, I have learnt my lesson

 

dont worry about an external boost controller. the stock computer is more than capable boost controller - IF TUNED CORRECTLY.

 

If you want to tune it yourself, get the required hardware and PCMTEC software, then you can change whatever you want. bbut id have to say, you may be better of finding a reptible tuner.

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Just looking at injectors doesnt really fully tell if they have been modified.  Plenty of stock drilled injectors out there 

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