Mods:

BNR Stage 4, 750/1000cc injectors, Rtek 2.1, 3" turbo-back exhaust, twin scroll removed, emissions removed, walbro 255, 3" TID, etc.

I have checked for boost leaks, there is a leak at the coupler entering the TB elbow, however I have fixed most. I am still running the stock TMIC, and my gauge shows 14psi at full boost, it seems that the MAP sensor reads high, or my boost gauge low. My next move will probably be methanol injection, possibly a FMIC too.

I am running 93 octane with premix. I am using arghx's moderate timing map, and my own fuel map.

The car pulls pretty hard, but it takes forever to get into boost. I can only hit 10 psi in 1st gear launching at 4500rpm. Full boost is around 5500rpm which is ridiculously high and makes the car feel pretty slow.

Any ideas on why boost takes forever to build? My only guesses is that the boost leak is hindering boost that much, or maybe the wastegate is not closing fully?

I have attached the complete log if anyone wants to take a look at it.

 

Boost leak? Leaking Wastegate? Sorry mang, Good luck though...

 

How bout you get rid of that tmic...Your pushing 14psi on somethign that isn't even designed to do much over 12 psi without hitting above 100 degrees C on a Stock turbo...your pushign a ton of air. and its incredibly hot i can imagine.

 

blown turbo? check the shaft play.

 

Removing the twin scroll wont be helping much neither.

 

Those intake temps are scary. Maybe clogged cats?

 

The car is cat-less. 3" straight all the way back. It was 95deg.F outside when I did this run.

Of course I need to work something else out on that. I am planning on doing methanol injection. You can push 25+ psi through the TMIC with a larger turbo even, but you need water/methanol injection. BDC is an example of that. I realize that if I keep it up I will blow the engine.

Turbo is brand new, and my airflow is there. I am maxing out the AFM. Boost is obviously holding strong until I let off the throttle.

 

check the wastegate, i have a stage 3 and mine was really laggy because it was adjusted where the flap on the wastegate was open all the time. I readjusted it and on the last datalog i did it made 5psi at 2800 rpm (on15psi) If thats not the problem id boost leak test it.

 

How do I go about adjusting the wastegate? Do I need to remove the clip to adjust the rod, or not? Also when looking at the compressor housing from the front of the car, do I turn the rod clockwise (towards the driver's side), or counter-clockwise to close it?

The car does have a boost leak. I have used a tester, which was the first thing I did. The only leak I know of is on the coupler going from the TMIC outlet to the throttle body elbow. I want to fix that, but I'm not sure if I should just go ahead and buy the FMIC kit.

What RPM did you hit full boost, the 15psi?

 

i have a bnr stage 3 and hit full boost 10psi around 3500rpm (ie...3.5" exhaust), when I first put it on I had a boost leak with the coupler going from the turbo to my intercooler and I couldn't hit more than 5psi...tighten down all of your clamps, should be pretty easy with the stock tmic

 

mine hit full boost around 3500-3700 rpm. To adjust it shut you remove the c-clip and turn the rod clockwise. Btw a fmic is worth every penny especially with anything bigger than a stock turbo.

 

do you have a boost controller? Depending on what controller you are using you may need to adjust the wastegate actuator arm to hold it closed tighter.

get rid of the tmic. you are gonna blow your engine with that

check to make sure the wastegate is hard closed.

You are not going to get full boost in 1st gear. Boost is based on load and 1st gear is not loading the engine long enough to get the turbo up to speed.

 

Is this an s4 or an s5 BNR stage 4? and yes, check your wastegate adjustment first but also tell us what boost controller you are using.

 

I looked back at the logs again. Your boost is oscillating a lot--more than would normally be considered acceptable. It sounds like a problem with the adjustment of the wastegate arm or a problem with the boost controller.

 

Might also be the pressure/vacuum source going to the gate. It needs to be off of the compressor directly or the upper intake manifold just past the throttle body at the surge plenum. Needs to be a non-pulsy source. Not an intake runner.

B

 

It's an S4 stage 4. I checked the wastegate yesterday, it was fully closed. I tightened it a couple of turns for good measure. The boost controller is the ebay, NXS ball-spring (lowes) type. I have not driven the car since.

Would a reasonably sized boost leak cause this? I made a leak tester and found a leak on the TB elbow. I am still on the stock IC hoses. I bought new silicone elbows on Thurs, so these should help that issue.

I use the barbed fitting on the compressor housing. My MBC is t-ed in there.

 

What size hoses are you using for the wastegate and boost controller?

 

Either 3.5mm or 6mm. I'm pretty sure that they're 3.5mm, I'll have to measure it tomorrow. What size should they be?

 

What did you expect? You have a dirty great big 60-1/p-trim shoehorned inside a hogged out S4 exhaust housing.

Perhaps take a look on the forum for spools of a T04S in a 1.0+ a/r housing and see that your result is probably as expected.

 

should be 6mm iirc. sometimes improperly sized hose can mess up boost control.

There is truth in this. My old T04S (60-1 with P trim) with .96 undivided turbine housing and HKS log hit full boost of 18psi at around 5500 actually, when using an MBC on an external wastegate. An s5 hotside and manifold would definitely help. In your current configuration It's not going to get much better, but you may be able to reduce the fluctuations.

 

J-Rat said in one of his older posts that he made full boost 17psi around 4500rpms on the same turbo. I was expecting to see something similar. He was also on stock ports.

The difference that I've seen with my car is that the boost doesn't drop off as RPMs rise. I have a feeling that the car should be pretty quick once I get it tuned and either fmic or chemical intercooling.

As far as the oscillation is concerned, the car was pretty steady at 14psi on my boost gauge. The boost gauge didn't match up with what the map sensor was seeing.

 

I bet the leak is 90% of the problem, get that fixed. Also check your exhaust gaskets, if they blew, you'll have tons of lag, also check to see that the plug for the twin scroll isn't leaking. any ehaust leak near the turbo affects performance negitively.

 

+1.

 

I replaced the intercooler couplers, the exhaust gaskets, and installed copper lock washers from pineapple racing. I also turned the boost down to 10 psi until I get some form of charge cooling on the car.

10psi by 35-3800rpms, feels so much stronger now!

 

Be careful. No charge cooler and even 10psi of boost is a lot of intake air heat.

B