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V1 SwerveMonkey's Street Goblin #197 - 08 Donor

Ross
I am wrangling with the task of putting together my own turbo header too.
Have you decided if you are going stainless steel, or mild steel and getting it ceramic coated?
I am wondering which will last longer, as the exhaust takes a lot of heat stress.

I see that there are stainless steel mandrel bent pipes available.
Or some companies have put together kits.
Header flanges available in mild steel, and in stainless steel.
 
SwerveMonkey
Still preparing for the Z54 Era....

• Stock Z54 turbo (Forum's classifieds)
• exhaust manifold

• compatible Oil Pan (?)
wastegate [ realizing that it is attached to the Z54 ]
• Oil and coolant lines
• intake manifold (?)
• Coolant crossover pipe (?)
• Intercooler
• Injectors
• Fuel management (e.g., HPTuners)

• Wideband sensor/controller



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Early June 2025
purchased Exhaust Manifold
RPM-motorsports
2.0T LNF / LHU / LDK K04 Exhaust Manifold (12602397)

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early July2025
injectors purchased from KSM-motorsports
1 x 80lb 840cc fit Siemens Deka FI114991 High Impedance (Long Style) EV6 / USCAR

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Early September 2025
purchased HP Tuners and credits... starting to learn how to correct any existing problems in car
looking to tune the vehicle to current running conditions for no CEL
found interference between Z54 turbine housing and the manifold purchased

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Mid-October 2025
Able to "turn off" Secondary Air Injection testing and some emissions checks in the ECU with HP Tuners
Created a spacer to allow the turbo housing to not interfere with manifold
Found that Thermostat housing may be interfering with turbo hot-side outlet.
 
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SwerveMonkey
trying to track down more data on the injectors i bought for tuning purposes...

KSM 840cc injectors
  • Flow rate @ 43.5 psi/3 bar: 80 lb/hr / 840cc/min
  • Static Flow Rate: 875cc/min
  • Dynamic Flow Rate : 18.6 mg/pulse 2.5ms PW, 20 ms Period
  • Fit Deka EV6 fuel injector - Long size

the wideband sensor as well as a different boost control will be needed... potentially considering building a manually controlled configuration using a needle valve set for 5 psi to flow as a threshold... more research needed to fully understand.

attached is last known good file for a NA setup, using this post as a milestone/insurance to leave behind.
able to tune-out the SAI checks as well as turning off unnecessary check engine light faults that are removed from the car.
 

Attachments

G
Get injector data or at least confirm that full GM format data is available before purchase.

The cross-reference numbers I found indicate those might be deka 80 injector that you can find data on HPT forum for. But they have a reputation for being very inconsistent injectors even if they are actually deka 80's.

No way I would be buying injectors from a company in Cypress.
 
SwerveMonkey
No way I would be buying injectors from a company in Cypress.

Welllpp!! guess I'm learning the hard way then, ha ha ha.
thanks for the heads up, I'm niavely finding out things and running up against each hurdle in this.
I've been trying to track down the injector data but also trying to understand each and every detail to it too... slowly but surely getting there.
 
SwerveMonkey
ok... first fairly decent day i got to wrench about in the garage... the 80# dekas are in and run like crap on the old tune...

I know it was risky to turn over the engine for long with the larger set, didn't have it on for long when i heard the engine on a rough idle...

I tried to push the tune to be rich in HPT with maxxing out the flow rate vs Pressure table as well as raising the Minimum injector pulse

HPTuners showed the starting Flow rate vs Pres values at 28.8 Lb/h and jumping to 31.2 lb/h around 60 -65 PSI...
I pushed those values way up to 61.6 lb/h transitioning to 63.5.... which seems to be my max for that setting.

Is this a limitation of the ECU or something "hard-coded" into the management for this model??

Min Injector Pulse-width began with 0.328 ms , across the board... raised to 0.531 ms

I'm surprised that the stock ECU has built in limitations that HPT won't adjust, but maybe that is something inherently built into the L61 ECU.... if any one has more info let me know, I'm eager to learn.

I'll be digging up more info into the ECU to see what other hurdles I have in front of me... for now it runs and idles fairly OK for being so rich.

below: flow rate vs pressure old & new
55861


55862
 
G
If you run into injector limits there are ways to scale the rest of the tune to make it work but I've never done it. Something like doubling the stoichiometric.
Double Stoich and Halve IFR Injector Scaling how to

But you will be better off with injectors that won't cause you to need to scale if you can get by with it.
Do you have full GM format data for your injectors? Not just flow rate?

And the table is pressure delta not fuel pressure so you have to take into account any boost. And GM doesn't always fill out the data correctly in areas they don't expect it to run.
 
Ross
Is your L61 running a stock tune, and you just added big injectors?
If so, then I would think your engine would be running rich.
You need to get your wideband O2 sensor working, and that will tell us if your are running lean or rich.
Well, technically even the narrow band will tell us that much. What is that reading?
 
SwerveMonkey
semi stock tune... simply adjusted a couple tables... still waiting on funds for the wideband sensor...
I'm still trying to make heads or tails of the VCM scanner data. Will post here after getting a good understanding of what i am looking at...
 
SwerveMonkey


 
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G
It's recommended to get your general airflow/fueling correct before worrying about idle. This is without reviewing the log so I'm not saying you airflow/fueling is wrong. But a lot of people worry about idle at first, and that will cleanup with proper airflow tables.
 
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