[ap485]

Originally Posted by JonEQuest

Are the pistons the same as the N54 engine?

No. N55 pistons are different.

[JonEQuest]

Originally Posted by ap485

No. N55 pistons are different.

OK thanks

[ap485]

Here's another update.

The engine has been running flawlessly for the last two months. At the same time, I have been working with a tuner and ran into boost control issue. Basically, I can't control the boost so, it overboost every time at WOT. We have tried different things in the tune but nothing seen to work. One thing for sure, the heads are flowing a lot more and the turbo is spooling a lot sooner than expected, too. I'm hitting 23-24 psi at 3200 rpm.

Now, I'm waiting to receive a new manifold with external wastegate from Bigboost. Hopefully, this will solve this issue.

[LoneWolfPistol]

Have a 13"-20" (width) Trans oil cooler , If needed send pm.

[ap485]

Originally Posted by Simplev33

Have a 13"-20" (width) Trans oil cooler , If needed send pm.

Thanks but I already have one installed a while back.

[weehe126]

Any issues with false knock so far? What psi are you trying to dial in?

[ap485]

Originally Posted by weehe126

Any issues with false knock so far? What psi are you trying to dial in?

No false knock issues.

I have been trying to dial in JB4 map 1 (16 psi). The only problem so far its boost control. WGDC goes to zero at WOT and the car still overboost badly. I have to let off otherwise the boost will climb above 30 psi.

[weehe126]

Originally Posted by ap485

No false knock issues.

I have been trying to dial in JB4 map 1 (16 psi). The only problem so far its boost control. WGDC goes to zero at WOT and the car still overboost badly. I have to let off otherwise the boost will climb above 30 psi.

Good to hear on the knock.

That sounds more like the wastegate is stuck closed than a tuning issue.

[ap485]

Originally Posted by weehe126

Good to hear on the knock.

That sounds more like the wastegate is stuck closed than a tuning issue.

Wastegate is working as it is supposed to. It's just that the internal wastegate can't handle the additional air flow cause by the ported heads.

[weehe126]

Originally Posted by ap485

Wastegate is working as it is supposed to. It's just that the internal wastegate can't handle the additional air flow cause by the ported heads.

That's odd, I would have assumed the wastegate would be sized for the turbo/power. The upgraded head just helps get you to that power. So you can't test out just spring pressure to see if it overboosts?

[ap485]

Originally Posted by weehe126

That's odd, I would have assumed the wastegate would be sized for the turbo/power. The upgraded head just helps get you to that power. So you can't test out just spring pressure to see if it overboosts?

The wastegate has been tested several times and it's working fine. I even leave it fully open and it still overboost badly.

IMO, the turbo kit was only tested on stock engine, and the internal wastegate capacity is fine for stock heads. Now, I have Stg 3 heads which aren't as restrictive as the stock ones and it has increase flow and velocity tremendously. So, an increase in flow into and out of the turbo requires an increase in wastegate flow to maintain boost on target. If wastegate is near capacity prior porting the heads then, ported heads cause a large increase in flow, freeing the system up can put the wastegate flow requirement beyond capacity at which point the boost level becomes out of control.

There are two ways to address this issue, either port the wastegate housing of the turbo or switch to external wastegate. I would choose to port the wastegate if the overboost wasn't that bad but, my case is so extreme that I would go for the external wastegate.

[ckanderson]

External waste gate will control boost better anyways plus, external dump

[take1step]

Originally Posted by ap485

Finally, I got numbers on the heads. Huge gains after porting

I recently built my engine too and ported the heads. I'm having similar a condition to what you previously described:
"A lot of fuel cut and hesitation during normal driving anywhere above 2800 rpm on any gear."

Did it end up being a mechanical issue or was it resolved by tuning valve lift/fueling tables?

[Ozzie335i]

Over on N54 there is a thread that a guy asks if an N54 without turbos would be as powerfull as an N52. The answer was no, due to the smaller port sizes of the N54. Apparently the forced air offsets the difference. ap485, I trust you took this into consideration. Other than an all out motor, is modifying the ports really necessary? I hope you get it worked out.

[ap485]

Originally Posted by take1step

I recently built my engine too and ported the heads. I'm having similar a condition to what you previously described:
"A lot of fuel cut and hesitation during normal driving anywhere above 2800 rpm on any gear."

Did it end up being a mechanical issue or was it resolved by tuning valve lift/fueling tables?

No mechanical issues. It's all in the tuning. Fuel tables were massaged and problem is solved.

Originally Posted by Ozzie335i

Over on N54 there is a thread that a guy asks if an N54 without turbos would be as powerfull as an N52. The answer was no, due to the smaller port sizes of the N54. Apparently the forced air offsets the difference. ap485, I trust you took this into consideration. Other than an all out motor, is modifying the ports really necessary? I hope you get it worked out.

The key to making power is moving air into and out of the engine. So, by increasing the airflow means more fuel can be added to the mix, and where there's more fuel, there's more power.

It just takes longer to tune it but, believe me it's all worthy.

[335xirookie]

Bumping this up because I'm interested on where your at with the build?

[ap485]

Originally Posted by 335xirookie

Bumping this up because I'm interested on where your at with the build?

Motor is running strong but still experiencing boost creep. Anyway, long story short, I got frustrated with my current turbo kit, and decide to ditch it, and go with different turbo kit with bigger turbo. New kit is already ordered. Now, I’m waiting to get it in the next few weeks.

[weehe126]

Originally Posted by ap485

Motor is running strong but still experiencing boost creep. Anyway, long story short, I got frustrated with my current turbo kit, and decide to ditch it, and go with different turbo kit with bigger turbo. New kit is already ordered. Now, I’m waiting to get it in the next few weeks.

What did you do with the old kit?

[ap485]

Originally Posted by weehe126

What did you do with the old kit?

It still on the car but will be for sale once I get new one.

[ap485]

Update:

As some of you may already know my car has been suffering from boost creep for a while. I have tried different things to fix the issue but nothing seems to work. First, the tuner tried different spool times and other variable changes in the tune and it didn’t work. Also, Bigboost sent me a spacer for the wastegate which supposedly helps the gate to open more so, I installed the spacer and still no luck. The problem is the internal wastegate can’t flow enough of the exhaust out due to an increased in exhaust velocity created by cylinder head work. I mean every time I go WOT the wgdc goes to zero (wastegate fully open position) and literally the boost keeps raising with no control. BTW, wastegate has been tested and it’s working as is supposed to. So, looks like an external wastegate is my only solution for boost control.

After long days of frustrations and false promises I decided to get rid of the Bigboost turbo kit and swap it with the new Speedtech kit with external wastegate.

I’ve talked to Jeff@speedtech for several months now about my situation and how his new N55 turbo kit with external wastegate would solve my issue. It’s basically the N54 turbo kit but without O2 bungs in the manifold. Anyhow, Jeff has been really helpful, knowledgeable and was able to answer all my questions and concerns in timely manner. After waiting patiently for a few months, the kit is finally here. BTW, the kit hasn’t been released yet but it will be soon.



Turbo selection:

I’ve been running the BB 3.4 kit with 6564 turbo for almost 2k miles now and I felt that turbo was kind of small for my car. The turbo spools faster than I anticipated, full boost (23-24psi) was by 3200 rpm. Based on that, I knew I have to get a bigger and laggier turbo. BW turbos always has been one of my top selection so, I used the MatchBot calculator on the BW website. After comparing different compressor maps, turbine sizes and A/R’s, I figured BW S369S-XE is the best for my application.

First impression:

This kit is all about quality. It so well designed and looks very promising. The cast manifold is all cnc inside and outside so, no unfinished, uneven or excess casting specially on the inside like other kits. It came with high quality silicone hoses and end flanges are welded very well too.







The kit came with high-grade silicone hoses which should work with high temperature with no problems. Anyhow, I got some DEI gold tape to protect them from the heat. There’s a few places that might get hotter than I would like from being that close to the turbo. Also, I got PTP T3/T4 turbo blanket which fits better than I thought it would.







Other Mods:

I will be getting rid of the JB4 and moving on to flash only. Nothing wrong with the JB4, it just difficult to find a good tuner and one that wants to work with JB4 these days. I will be using GFB G-force III to control boost and AEM wideband for AFR safety. Also, I’m planning to run DI only now that I got the SpoolPerformance Helix 4x.

[The Silver Slammer]

It looks BEAUTIFUL!!!

[ap485]

Originally Posted by The Silver Slammer

It looks BEAUTIFUL!!!

Pictures doesn't do justice to the quality and details on this kit.