Boost limit and torque control

AJP turbo · September 17, 2014, 01:57:50 AM

Not sure if this is the appropriate section but...

I have a 2014 SHO PP. GDM1 ECU code. Tuning with SCT PRP. I have the 3 bar MAP sensor and Air Raid CAI and Catless DP's are my only mods.

I can only get up to just barely over 15psi and right about 200-210kpa when I log. I was really hoping for about 17-18psi and I'd be happy but it's not happening. I'm not quite out of fuel and knock counts are fine.

Actual throttle is being cut down to about 35 when I log and I have no idea why. I've adjusted torque settings and torque truncation and commanded torque in SCT PRP. I'm wondering if there is a hard boost limit or torque limit that SCT doesn't have tables for or maybe it's a hard limit in the ECU like the old cobra's that had an airflow limit.

Is anyone running higher than 15 psi? Especially in a 2014? I know there are major changes in the processors after 13' when compared to the older SHO's

crash712us · September 17, 2014, 08:26:37 AM

Not unless they are meth injected. 15psi is about the max you'll see.

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SHOnUup · September 17, 2014, 08:47:35 AM

Sounds on par with stock turbos.

wasinger3000 · September 17, 2014, 09:13:04 AM

I see 17-18 psi all day on 91.

Wilson · September 17, 2014, 12:13:14 PM

When I had my Unleashed tune, I saw spikes of 17 all day

AJP turbo · September 17, 2014, 11:34:09 PM

I'm not talking about boost spikes a lot of people seem to think it's a limitation of the turbos but its not . it is an imposed boost and/or torque limit by the ECU.most people do not data log to actually see what's going on. Their tuner tells them they are at the limit when in reality they just don't know how to get around the boost and torque limits applied by the ECU

Also When I had the 2 bar map sensor in there I would see 206 kpa which is right at 15 psi. So I can't really understand why all these people put in the 3 bar sensor and still only run 15psi. I understand the need to have the ability to see past 15psi incase of boost spikes for proper fueling but the ECU can handle that anyway via STFT's. so there is some headway there anyway.

AJP turbo · September 18, 2014, 01:11:20 AM

Quote from: crash712us on September 17, 2014, 08:26:37 AM
Not unless they are meth injected. 15psi is about the max you'll see.

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What does Meth have to do with it? I understand meth can make higher boost levels more efficient and even safer for a given fuel if you've reached a point where the fuel can no longer resist self igniting due to high boost and or high compression but it has nothing do do with how high the turbo can spin up to.

BiGMaC · September 18, 2014, 01:42:44 AM

Turn off the grannies.... That should answer your question.

SHOdded · September 18, 2014, 03:11:53 AM

Efficiency and longevity are the OEM concerns, so they program the ECU and choose the hardware that way. Info on the turbos (assuming they are the same in 2014). More on this turbo here. Turbo tech (if you need it) here.

wasinger3000 · September 18, 2014, 11:54:58 AM

Quote from: SHOdded on September 18, 2014, 03:11:53 AM
Efficiency and longevity are the OEM concerns, so they program the ECU and choose the hardware that way. Info on the turbos (assuming they are the same in 2014). More on this turbo here. Turbo tech (if you need it) here.

How come they list the turbo as oil cooled? I know it's oil lubricated but also has coolant flowing through it.

glock-coma · September 18, 2014, 12:48:39 PM

Found this

The EcoBoost twin turbos are water cooled. Water cooling the bearings solved the problem. During normal operation, engine coolant is cycled through the center bearing. When the engine shuts off and the water pump stops, the coolant flow reverses and the EcoBoost uses thermal siphoning for water cooling. Coolant near the extremely hot bearing picks up heat, boils and flows away from the bearing water jacket. This pulls fresh, cooler coolant into the bearing water jacket, which picks up heat and cools the bearings. This cooling process continues silently until lower temperatures are reached, providing key-off protection for the turbo bearings.

To test this thermal siphoning process, Ford ran the EcoBoost engine at Wide Open Throttle and maximum boost for 10 minutes. Then the engine and all the cooling was abruptly shut down. The turbos were allowed to "bake" after this high-speed operation. This is exactly the conditions that would "coke" a center turbo bearing from the 1980s. They repeated the test 1,500 times without an oil change. A teardown of the turbo and inspection of the bearings validated the method of water cooling the turbo bearings.

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IHeartGroceries · September 18, 2014, 01:28:31 PM

I like that article is juiced up a tad to make it sound like Ford was the first to implement thermal siphoning water cooling. It's been used for many years!

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91hybrid · September 18, 2014, 09:05:40 PM

Right now I spike at 236 kpa with the up shift to third and I am gradually dropping from there to 198kpa at 5750 rpm. This is on my '14.

It did that before the meth too.

glock-coma · September 18, 2014, 09:41:21 PM

Quote from: 91hybrid on September 18, 2014, 09:05:40 PM
Right now I spike at 236 kpa with the up shift to third and I am gradually dropping from there to 198kpa at 5750 rpm. This is on my '14.

It did that before the meth too.

Waaaaa? 236 kpa is like 34 psi

91hybrid · September 18, 2014, 10:10:32 PM

That's manifold pressure... so to get boost, 236-100=136/6.80= 20psi...198=14.4psi sorry.

I have seen singular spikes as hi as 23+ psi which makes the rail pressure drop pretty quick. lol

John