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Is it weird that my car makes 16psi of boost on a hot day, with iat's around 30-35.

But when the iat's are 25 or below it makes 12psi at an absolute stretch, seeing 8psi commonly on cold nights and 16psi on hot days.


Colder temps means more dense air, means more boost.... Right? 🤣

Edited by biddie_fiddler
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Oi let's get all social media about it...   If this post gets 5000 likes, I'll fit a gen 2 gtx35r to my territory this week and run 18psi through it.   Since we're here in fordvill

A week or so ago my little (19yo) brother was being a pain in the arse to middle brother.   Now LB is always leaving his sh*t lying around, wallet, keys, sh

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yeah, normally you make more on colder days... your tune must have allowances for protection on colder days to prevent overboost but doesn't on warmer days... only a guess, though.

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Closed loop on the FG is based off IAT’s, greater the IAT greater the base D/C and target boost


it’s common for tuners to use the hard work ford put in basing this variable on a variety of factors and just adding a few psi to the target boost table to generate a result. 

It’s an ok way of doing it but more effort is required from your tuner for consistency once modified ;)

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So does that mean that is it normal behaviour then?


I have no idea what strategy Rob uses in his tunes, all I know is he uses PCMTEC and that the dyno sheet says its tuned to 16psi, so seeing it run at 8psi had me quite confused. Checked all the IC piping cause I thought I had a boost leak 😂


Secondly, does that mean that with the lower boost on colder nights that its still making the same/similar power compared to what it was tuned to? It doesn't make sense in my head as to why that would be true 

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That's not normal I would be checking your turbo, compressor wheel and boost control. Or call the tuner to see if it was happening on the dyno or some other random weirdness. Is it a proper boost gauge or obd2 thing.


8psi even in closed loop

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Well I contacted rob and he said its normal.


I'm not 100% sold on it. The difference in a pull at 16psi compared to 10-12 is really noticeable. Did one on the way home from uni yesterday arvo with IATs around 38C, 16psi and pulled like a dream.

Did one this morning on the way to work with IATs around 28C, hit 12psi. Still pulled pretty good but judging by the butt dyno it didn't feel no where near as hard. 


Car was tuned when the ambient temps were 27C so IATs would have been around the 28-30c area. It seems that anything below that the boost just dies off. Kinda sucks cause when its peaking at 8psi it feels like it did when it was stock 🤷‍♂️

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As I mentioned it’s “Common” for big workshops to take this approach as you can knock out a tune in like 4 pulls and send the vehicle out the door 


“Global” changes are fast,easy,pretty reliable for what the desired result will be. 

This isn’t how I do it and I want to maintain that target boost all the time every time unless we start to get super cold or IAT’s/MCT beyond what the hardware package can deal with. Yes this takes more time to complete ;) 


On an ambient temperature day of say 27* MCT on a Dyno will be around 38-45* and thus usually the area that gets tuned - “IF” you were to look at your tune you would see 16 psi in this area of the target boost map for closed loop boost control, heavy drop offs under this area which you’re experiencing 


Not exactly great as cooler intake temps “Should” allow for a better power production atmosphere and should be utilised in the tune as such 

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Yea, but this is Rob we're talking about. Its not like its just "one of them" shops. Monsta Torque has an extremely high reputation in Perth and is regarded as "the best of the best" when it comes to barra's in WA.


He had a lot of cars to tune in that week mine got done. He was stuck in 2 week iso after seeing his family over east and came back to find out the floors in his new shop weren't done / not done properly. So his plan to move shops has been severely pushed back, he is a very busy man and I feel bad if I go bug him about this tune 😕


Might get the forscan running on my crappy laptop again and log some data, get some basic data and see whats going on. 

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Happy Hump Day Keiffy

how u doing? 

I cbf this afternoon... flat AF in the middle of a bunch of projects. 

this is what happens when I try and manage my 50yo sparkie 😂



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