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hey everyone

for those who read this post i am grateful for the time you take and hopefully you will have an answer for me.

i have recently installed a precision high flow turbo and have added supporting mods such as sard 550cc injectors, walbro fuel pump, intercooler, 3inch exhaust, running a greddy profec spec b and remap of the stock ecu.

my car is only making 184 kw atw. it should be making at least 200kw. first of all my car is running 16psi and dropping back to 14psi and i would like some helpful hints to find that problem. all hoses have been checked and tightened. what else could it be?

but my main question is about the dyno sheet of the air fuel ratios. there is a dip in graph, i cant work out what it is. could you please help me out with this. tonight i will be hooking up my consult software and checking a few things and will have more info tomorrow.

thanks

aaron

PrecisionR32_AFR.jpg

PrecisionR32_KW.jpg

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There may be issues that are causing that dip with the ECU or the way it is able to be tuned etc etc....

With a power fc it would be easy to remove that dip.

Its not really fair to go blaming the tuner and give them a bad wrap for something thats probly not even his fault.

Yes it is running pretty rich at 5,500 rpm and he would never blow that engine up. but there could be issues that are causing this that the tuner had to compensate for.

anyone got any other afr graphs for remapped rb20 computers?

well it is a rb20, so there is the first problem, LOL.

i assume you are running a manual boost controller? if yes, then there is the cause of the boost drop.

the afr's could be a fair bit leaner. they are close to 11 but could be up around 12.

it also depends on how much timing they put into the car, what compression you are running (how strong your motor is), etc.

well it is a rb20, so there is the first problem, LOL.

i assume you are running a manual boost controller? if yes, then there is the cause of the boost drop.

Actually the first post says he is using a Profec B Spec II

hehe >_<

I can offer a bit of advice,

The dip in the AFR's have been put there for a reason however they are a bit over emphasized. I will explain...

The dip to 10.5:1 happens at exactly 4000rpm, this is where you are hitting full boost. with a turbocharged engine you will be at peak volumetric efficancy at full boost and peak torque almost instantly after. you are most likely to suffer detonation at this point so adding fuel (to a certain extent) will reduce the possibility of detonation.

this is what has been done.

also just by looking at the power curve you can see that timing has been reduced between 4200 and 5600 rpm. seeming as you are running 16psi as a rule of thumb with 98 octane BP ultimate you should be running around 18deg at peak torque and then 19 and 20 deg in the following cells.

this is due to the engine becoming less volumetrically efficant at higher RPM (that combined with the fact that boost is tapering off)

I would be happy to have a look at the remap for you and see what needs doing to correct it.

(QUICK EDIT)... you should be able to safely run more boost. looking at the way boost is ramping up you are only just in the efficacy of your compressor. 17psi would make a lot more power especially if you were able to hold it to redline

it could be the stock actuator, it could be a restriction caused by the intercooler, the dump pipe, the cat or a muffler. some intercoolers, dump pipes, mufflers, cats flow better than others, but it does just seem to flatten out at about 14psi from 5600 onwards so it may be be in the settings of the controller. it only holds 16psi for for 100 or 200rpm.

the boost tapering off is not a restriction :P it is related to the controller setup and I am betting the controller is getting its boost reading from a nipple on the front of the compressor housing. if placed past the elbow by about 30cm you will get the most stable reading :)

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