[gray_shark]

I have upgraded my 2013 12C with full exhaust system from Larini (catless type), ISG removal, and PURE turbos upgrade tuned by M-engineering. Car made a good power on 91 pump gas around 680-720whp one month back. I drive my car every weekend and sometimes in the week days. I tested and tool a log on the street and the new power was noticeable.

I took the car today to test with the pump gas map to see what the car is capable off in quarter mile. However, on my way to the track, I done a quick pull on street (car felt loss of power) and got a message "engine system failure" and there were two codes shows in the scan:

• P0234 Boost pressure control: Bank 1 over Boost
• P02CA Boost pressure control: Bank 2 over Boost

I cleared the code, put tire pressure on 25-26psi (toyo888r on rears), then tried my first ever pass with this car, and unfortunately car was not pulling hard at all: made 12 second with around 127mph!

Visual inspection in the track does not much help in finding any issue, then I drive back from the track back home normally.

What could possibly the issue? also the tire low pressure messages was annoying, getting the launch control to work is tricky sometimes or it is me I don't know how to use it lol

 

[gray_shark]

The issue is probably your "upgrades".

Clearing codes, without doing anything to address the cause, then thrashing it, isn't a good idea either.

The upgrades are fine and car is tuned and log is reviewed.
After clearing the code it did not return back even after the run and that's why I stopped taking another test knowing there a real problem. Without the test, I wouldn't know

 

[gray_shark]

I would reach out to m-engineering. They may ask you for a data log of the event. Typically that code throws on a catless car without a tune. They should be able to tell you what is going on.

I will, but unfortunately, I did not have the chance to take a data log for this run, it is prohibited to make a run with laptop - not fixed - inside any car

Not sure if this is hose or vacuum leak can cause such power loss, I might put it on dyno again to take data log and then inspect the car fully

 

[gray_shark]

Did you do the tune before or after the modifications? One modification after the tune could be triggering it, particularly the downpipes. You might also check to see if the pipe between the air box and MAF is still connected and seated correctly.

Of course, we tuned the car after the modification by best of M-engineering, we tested and make sure the data log are good on dyno jet. We will check that pipe between air box and MAF

 

[gray_shark]

You removed the cats and fitted bigger turbos, then saw an over-boost problem. Why do you not think that they're related?


Or give it another chance to go bang ..

Personally, I wouldn't ignore this. The lack of power isn't a good sign.

The car tuned on dyno and tested on street with data log and all was good. Just the issue for some reason appeared and the over boost might related to over spinning maybe, not sure even if it is related to actual power loss. I'm wondering of it is common maybe for some pipes to goes off and case such power loss or something else. Wil check the car and report back.

 

[gray_shark]

We inspected the car, found passenger clamp little lose of turbo and intercooler pipe but we doubt this is the reason. We tighten it and put the carbon dyno. It made 590whp only!
No overboost issue which I think it might appears only on street when also tires spins.

Sent all data logs to m-engineering to see their input.

 

[gray_shark]

Quick update,
Car performance seems not consistent due to IAT sensor and its impact on the tune. Heat soak and high reading of IAT (Intake air temperature) caused power reduction and retarded ignition timing. The ambient was around 25c(77f) but the IAT reading was very high around 69c (156f) before making a pass in dragstrip! seems moving at low speed and setting idle in the lane for long time caused such power loss issue. However, checking different logs of WOT at 35C (95F) days seems to have some power loss as well due to the safety in tune (timing retards) and false positive high IAT temps due to heat soak of IAT.

I replicated the same scenario while driving ON STREET and tried to observe the IAT when cruising or when setting at idle, shutting off the car, starting, moving at low speed, etc. Conclusion is the higher outside/ambient temp is, the worse the situation it gets with heat soak. Driving at medium speed, will bring the IAT down but not so quickly and not close to the ambient at all and still IAT will read high temperature due to heat soak from engine bay, exhaust most probably, etc.

Thinking of possible solutions:

• Have anyone thought off relocation of the IAT sensor to a cooler place where it is less prone to heat soak? where is that IAT sensor located actually on 12c/650s?
• Try to insulate/wrap the exhaust manifold, sensors, radiator hoses, intercooler?
• Methanol injection (is it helpful to get the starting point of IAT lower? because if it like reading 70c then you sprayed meth, it will cool down, but still you lost power, and according to m-engineering, the tune read from low ignition table sue to high IAT reading) so not sure if this will help the situation from the base start.
• Adjust the tune not to retard timing until high IAT, but it seems not good idea if you get to that high temperature somehow and not pull the necessary timings
• Better control IAT via standalone ECU like syvecs as might the stock ECU is reducing power/torque because of different calculations/factors like highs temperature where it is not discovered/known by current tuners
• Any other idea to try?

Living in hot climate areas like 85f+ you will immediately lose power after first pull or after driving and reaching to the racing area unless if you race immediately after a cold start like drag race cars lol

 

[gray_shark]

Moving the AIT sensor to show a lower temperature to manipulate the tune is like closing your eyes while you get robbed. It doesn't make a good thing happen, it just masks the bad. The failsafes are there for a reason, to protect your engine from blowing up.
Yes, wrapping the exhaust will help with engine bay temps, possibly quite a bit if you do it right. Intercooler and other items you might try gold tape.
Meth injection WILL bring down temps but while idling it won't do much I suspect.
Adjusting the tuning is the same result as changing the temperature sensor location, bad.

The best thing you can do is NOT idle it, push it through lanes till you get to the line.

Thanks for your support and taking this step by step with me in private, very informative. The idea not to fool and IAT to read colder air, it is actually the quite opposite where to find a solution for such sensor that enable it to read the actual/close to ambient temp or actual air temp before entering to engine.

Current issue shows (not specific to Mclarens) that IAT sensor is pro depending on its location, IAT design and material, engine bay temp, ambient temp, exhaust close to IAT, modification to car is that IAT sensor is prone to heat soak issues which causing incorrect reading of the actual air temp going to engine. The other issue I see on my car, once the sensor heat soaked , it will not cool off quickly to same 10 degree of ambient after long/normal cruising. I might be wrong thought, but at least this is my experience on my car in past weeks. I was monitoring the IAT readings with OBD/Torque app and it is really heat soaked close to grilled sensor lol, especially for short runs, stopping the car, riding again, etc. Outside temp now around 37c.

Pushing the car to the lane like a drag race car is not a good option for me, also I might do that for an ultimate pass/record. However if you are in competition, and you will have minimum 3 drag passes, you are done with this issue

Anyone have a picture of the IAT sensor or part# ?

Thank you