[Davidschu]

Hi all. I'm having some issues with my boost tapering off really bad after about 4400 rpm. This is an issue I first noticed a while ago when I flashed bm3 stage 1. Car felt like it had tons more power vs the stock tune down low but not much up top. Getting on the highway the car feels so much stronger pulling from low rpm in 4th gear vs starting mid rpm in 3rd.

I looked at my logs then and noticed my boost was tapering off really bad. Thought I might have a leak. Upgraded my intercooler, double checked that the ic/cp connection was good. Still had the same taper issue.

I know that pwg cars do have an issue with not holding boost well in high rpm. However the tune made by bm3 is specifically for pwg cars and targets around 16 psi in the upper rpms so I assume a stock pwg car should be capable of hitting that. However, my actual boost psi is tapering down to around 10 psi by the time I hit 6k

So I thought maybe a catless downpipe would help my turbo flow better. So I went that route and flashed stage 2 91 yet I am still seeing the same issue in my logs.

As I mentioned before getting on the highway in 3rd feels weak compared to 4th. I looked at my logs and the boost target in 3rd drops down to around 10 psi, yet in 4th and 2nd it's around 15-16psi. Not sure why this is happening.

I think it's possible I have a leak however it's weird that the car can hold 15psi up until 4k rpm which makes me think there's not a leak. However, I have ordered new bigger o-rings for the ic/cp connection and also plan on creating a boost leak tester based on one of the threads I read on here. I would also like to note that I have a stock diverted valve and have 65k miles.

So does anyone have any insight on why my 3rd gear boost targets are so low? And does anyone with a pwg car with stock turbo have logs to compare to? Thanks in advance

Here are my logs: First two are 4th gear pulls, last two are 1-4 pulls

http://www.bootmod3.net/log?id=5e43449ec090c6419c25d19c

http://www.bootmod3.net/log?id=5e43440dc090c6419c25d19a

http://www.bootmod3.net/log?id=5e43441ad10b432feef138ec

http://www.bootmod3.net/log?id=5e43440ed10b432feef138ea

[n55david]

Do you have the trans flash?

[harkes]

Problem is bad tuning. F-series is notoriously difficult to tune. I own a 2012 PWG myself and I have been trying to get it running perfectly with Pure Stage 2 for +3 years (first JB4, then ESS flash, then JB4 with BM3 backend flash, then BM3 flash alone, now MHD). I am now on revision 47 (!!!) with Twisted Tuning and the car does the same as yours. Inconsistent boost in the different gears.
I have now found hope in Pureboost (Fabian Baum) which seems to know what he is doing. He is also the man behind the PWG PS2 OTS map for MHD.

First picture is Twisted Rev 47
Second picture is Pureboost Rev 1

[Techno 9000]

”So does anyone have any insight on why my 3rd gear boost targets are so low? ...... Thanks in advance”

From what I have read, 3rd gear is torque limited by the transmission, is it not?

Anyone else agree?

[harkes]

Originally Posted by Techno 9000

”So does anyone have any insight on why my 3rd gear boost targets are so low? ...... Thanks in advance”

From what I have read, 3rd gear is torque limited by the transmission, is it not?

Anyone else agree?

10-11psi will not get you anywhere near the torque limiter

[Davidschu]

No trans flash. The previous owner did have the m-performance power kit installed but I don't think that does anything to the trans. And to clarify my car is an 8 speed a/t.
Harkes looking at your log in both pictures it looks like your targets are 18-20 in 3rd gear. Sure your not reaching them in the first picture but that's target. My target in 3rd is only 10-11. If it's caused by bad tuning is everyone that's running ots bm3 maps seeing this ?

[oma3710]

I am having same issue with my custom tune on ewg. Target is 22psi and after 5k rpm I am hitting around 17psi.

[oma3710]

Originally Posted by Phantom10R

Do you have the trans flash?

Does the trans flash cause this?

[harkes]

Originally Posted by oma3710

I am having same issue with my custom tune on ewg. Target is 22psi and after 5k rpm I am hitting around 17psi.

17psi is the physical limit of the stock turbo. Nothing can be done to make it hit 20psi.

[oma3710]

Originally Posted by harkes

17psi is the physical limit of the stock turbo. Nothing can be done to make it hit 20psi.

I know other people on this forum with same mods hitting 20psi all day with the same tuner.

[harkes]

Originally Posted by Davidschu

No trans flash. The previous owner did have the m-performance power kit installed but I don't think that does anything to the trans. And to clarify my car is an 8 speed a/t.
Harkes looking at your log in both pictures it looks like your targets are 18-20 in 3rd gear. Sure your not reaching them in the first picture but that's target. My target in 3rd is only 10-11. If it's caused by bad tuning is everyone that's running ots bm3 maps seeing this ?

Ok, let's not say bad because it works. Let's call it sloppy. You will not see that in the factory map.

[akgambino]

Originally Posted by harkes

Problem is bad tuning. F-series is notoriously difficult to tune. I own a 2012 PWG myself and I have been trying to get it running perfectly with Pure Stage 2 for +3 years (first JB4, then ESS flash, then JB4 with BM3 backend flash, then BM3 flash alone, now MHD). I am now on revision 47 (!!!) with Twisted Tuning and the car does the same as yours. Inconsistent boost in the different gears.
I have now found hope in Pureboost (Fabian Baum) which seems to know what he is doing. He is also the man behind the PWG PS2 OTS map for MHD.

First picture is Twisted Rev 47
Second picture is Pureboost Rev 1

Ps2. Seems irrelevant to this discussion.

[akgambino]

Originally Posted by Davidschu

Hi all. I'm having some issues with my boost tapering off really bad after about 4400 rpm. This is an issue I first noticed a while ago when I flashed bm3 stage 1. Car felt like it had tons more power vs the stock tune down low but not much up top. Getting on the highway the car feels so much stronger pulling from low rpm in 4th gear vs starting mid rpm in 3rd.

I looked at my logs then and noticed my boost was tapering off really bad. Thought I might have a leak. Upgraded my intercooler, double checked that the ic/cp connection was good. Still had the same taper issue.

I know that pwg cars do have an issue with not holding boost well in high rpm. However the tune made by bm3 is specifically for pwg cars and targets around 16 psi in the upper rpms so I assume a stock pwg car should be capable of hitting that. However, my actual boost psi is tapering down to around 10 psi by the time I hit 6k

So I thought maybe a catless downpipe would help my turbo flow better. So I went that route and flashed stage 2 91 yet I am still seeing the same issue in my logs.

As I mentioned before getting on the highway in 3rd feels weak compared to 4th. I looked at my logs and the boost target in 3rd drops down to around 10 psi, yet in 4th and 2nd it's around 15-16psi. Not sure why this is happening.

I think it's possible I have a leak however it's weird that the car can hold 15psi up until 4k rpm which makes me think there's not a leak. However, I have ordered new bigger o-rings for the ic/cp connection and also plan on creating a boost leak tester based on one of the threads I read on here. I would also like to note that I have a stock diverted valve and have 65k miles.

So does anyone have any insight on why my 3rd gear boost targets are so low? And does anyone with a pwg car with stock turbo have logs to compare to? Thanks in advance

Here are my logs: First two are 4th gear pulls, last two are 1-4 pulls

http://www.bootmod3.net/log?id=5e43449ec090c6419c25d19c

http://www.bootmod3.net/log?id=5e43440dc090c6419c25d19a

http://www.bootmod3.net/log?id=5e43441ad10b432feef138ec

http://www.bootmod3.net/log?id=5e43440ed10b432feef138ea

There is nothing wrong with your car or the tune. Anyone who says the stock pwg turbo can hold more boost between 5000rpm and redline is full of shit. Even if wgdc was maxed out it would make little to no difference and be running that tiny turbo so far out of its efficiency range that it wouldn't make any more power either.

It's just the curse of the pwg, ewg cars hold around 3psi of boost to redline more due to a larger diameter turbo impeller and more refined wg control that is handled by the dme instead of vacuum.

All you can do to fix this is upgrade to a PS1 turbo which will put the boost in line with what a stock ewg car would be and maybe a bit more or ultimately go PS2 or comparable stage 2 turbo.

The 3rd gear issue is torque limiter same thing in 6th on 8at cars. Get a trans flash from xhp to resolve.

You could try going the custom tune route but don't go into expecting more boost in the upper rev range, more focus on fueling and timing which when done properly and specific to your car, octane and ambient conditions will net better times/power/feel than a couple more psi of boost ever would.

[btetier]

Originally Posted by oma3710

I am having same issue with my custom tune on ewg. Target is 22psi and after 5k rpm I am hitting around 17psi.

Dude you are really pushing your stock turbo to the limit if you are targeting 22lbs of boost. The stock EWG turbo's efficiency range ends around 5400-5600rpms, so that is why your boost tapers off after that. Also, why not just upgrade your turbot to a ps2 and run a more moderate tune, get higher numbers, and it will be much safer on your car. Pushing 22lbs on a stock turbo is going to cause it to go bad so much faster.

[Davidschu]

Based on my first 4th gear logs I'm hitting 13.3psi while targeting 16.1psi at 5000rpm

In the 2nd 4th gear log I'm hitting 12.9psi while targeting 15.5 psi at 5000 rpm.


And at 6k rpm I'm getting 11 psi with 16.3 target in run 1.

In run two I'm getting 11 psi with 16.2 psi target at 6k.


And if you look at the logs the taper continues downward as the rpms raise.

Is this really all I can expect from the stock pwg turbo with a fbo setup? Why would ptf have the targets set that high for pwg cars if the boost falls off that early at only 5k rpm?

And that is great news to hear that the trans flash will fix my low boost targets in 3rd. I will definitely be purchasing shortly

[akgambino]

Originally Posted by Davidschu

Based on my first 4th gear logs I'm hitting 13.3psi while targeting 16.1psi at 5000rpm

In the 2nd 4th gear log I'm hitting 12.9psi while targeting 15.5 psi at 5000 rpm.


And at 6k rpm I'm getting 11 psi with 16.3 target in run 1.

In run two I'm getting 11 psi with 16.2 psi target at 6k.


And if you look at the logs the taper continues downward as the rpms raise.

Is this really all I can expect from the stock pwg turbo with a fbo setup? Why would ptf have the targets set that high for pwg cars if the boost falls off that early at only 5k rpm?

And that is great news to hear that the trans flash will fix my low boost targets in 3rd. I will definitely be purchasing shortly

Yes, this is all completely normal for stock pwg turbo.

[harkes]

Originally Posted by oma3710

I know other people on this forum with same mods hitting 20psi all day with the same tuner.

At what rpm? Stock turbo can do 20 at 3000 but not at 6000

[Davidschu]

That's disappointing to here, guess I'll have to start watching some ps1 installation videos. Was really hoping I'd be able to hit the boost targets in the current ots tunes. Anyways I still plan to do a boost test shortly to see if I can squeeze out a little more psi.

Just to verify the xhp trans flash will raise my 3rd gear boost targets to be similar to the other gears? Thanks

[harkes]

Originally Posted by Davidschu

That's disappointing to here, guess I'll have to start watching some ps1 installation videos. Was really hoping I'd be able to hit the boost targets in the current ots tunes. Anyways I still plan to do a boost test shortly to see if I can squeeze out a little more psi.

Just to verify the xhp trans flash will raise my 3rd gear boost targets to be similar to the other gears? Thanks

No. xHP is only influencing how your transmission operate not the engine. Unless...you are exceeding the transmission torque limits, in which case the TCU will ask the DME to limit power, but that is not what is happening in your case. With xHP installed torque limits in all gears is 885ftlb.

[bplant13]

Originally Posted by Davidschu

That's disappointing to here, guess I'll have to start watching some ps1 installation videos. Was really hoping I'd be able to hit the boost targets in the current ots tunes. Anyways I still plan to do a boost test shortly to see if I can squeeze out a little more psi.

Just to verify the xhp trans flash will raise my 3rd gear boost targets to be similar to the other gears? Thanks

BM3 has a TCU tune specifically to address the lower torque limits in 3rd and 6th gear on the 8HP45 transmission. So you can start by flashing that with your BM3 platform for free. XHP does a lot more than that, but at an additional cost.