Ramp rail pressure higher as the RPMs rise because the HPFP becomes more efficient so can support more pressure. More pressure means shorter injection times and as you know the injection window gets shorter as the RPMs rise. I run as high as 18mpa up top. You need more injection angle advance. Pick low boost like 25 psi and keep advancing injection timing it until it mis fires then back off 10* (hint you can do a lot more than 40* of advance) You need to do the opposite you need to pull out some from the inection constant and add that same percentage back into the MAF so that MAF and VE are closer together. If MAF is reading 26 lbs/min and VE and 52 lbs/min the ECM gets pissed because it thinks there is a major fault. You can trick VE airflow though by playing with the optimum spark tables but I do not recommend it.

thanks Term, I appreciate it!

what diameter tube is the maf in?

3" tube

kinda forgot about this thread, but I was thinking just scale the map down

at the moment, tuning is just focused on Turbo dynamics and how they interact w/ each other during low and high boost. Spool characteristics using different wg set-up.....


Not focusing of how to build power........timing and etc.



UPDATE 1:


Rick Gifford aka BTF (my tuner) tried a couple of set-up for the small turbo's wastegate

First one (ABSOLUTE) is with the pressure line from the GT42 discharge hooked to the top of the primary (60mm) gate. It made 19psi by 3500. Turbine pressure is also very high, there is 8-9psi more turbine pressure then boost.


Second one is (RELATIVE), the gate is open to the atmosphere on the top of the primary gate. It spools alot slower, but it made the GT42 take over fully on the top end. Boost pressure is higher then manifold pressure, that's how big power is made. At high rpm when the GT42 is making all of the boost (only at this wg set-up), the PR of the primary stage is below zero, implying a pressure drop across the little one. This means that the little one is freewheeling in the wind at high rpm.(again, only in this wg set-up) The drop across the entire system is less then a few psi. Implying that the whole coldside flows enough for us for now.

BTF will try and set up the pnuematics to be a hybrid of absolute/relative. Start out with the gate nailed shut and then transition to full on GT42 action.

UPDATE 2:

regading fuel issue we had before.......increasing the fuel pressure to commanded 18mpa fuel rail pressure and upgrading to opel injectors........we are now getting 3.4-3.8 ms at 7500 rpm! They both helped dramatically.


UPDATE 3:
we are adding oil scavenging system for both turbos. Thanks to TURBOWERX.COM for the sponsorship of their Exa-pump and Exa-Pure filter!!!

Attachment 21076

Attachment 21077



UPDATE 4:
Now that we know that the gt2871r is not being choked by the gt4294r, and I would like to have a faster spool, we are replacing it with a gt2860r.


We will still use the Tial turbine housing of the gt2871r, since all these gt28 turbos can share turbine housings.


Attachment 21078

cfg used on this compound tuning is specific to MPVI sensors and a custom table to log afr error for the split second R4 controller (PI injectors)

Are you running 4 additional injectors? How big? Do they all fire together or in firing order?

Yes , I have 4 additional 45lb PI injectors.

They fire during high rpm/high boost

So they will be firing when the valve is shut too?

I like these updates, and that you want more low end boost!:twothumbs

Worst part of adding four extra injectors, puddle city

He was asking if they all fire at the same time, or if they are timed individually by cylinder and crank position.

Yes thanks Matt you explained it way better than I did

split sec a1c1 controller is based on the tach signal provided by the coils.

its only spraying at 20+ psi and during high flow rates.

I DO NOT believe there are some fuel puddling.


while Im sure there is some wall wetting occuring, as with all PI engines.................you would be suprised to find that most PI engines spray on a closed valve

it just boils the fuel on the back of the intake valve


currently, we have no fueling issue.....which is a good thing! :)

Bye K1, hello Carillo Pro H-beam rods!!!! We'll install these bad boys to make sure my block can handle 800hp of compound turbo power all day w/o even sweating!

Thanks to "project scarab" for providing the rods! :)

Attachment 20880

I also have Carillo rods :)

Sweet!

I wish, I had these carillos installed to my Bates sleeved block first time around!

Set it and forget it! :)

dim pistons

Well, today, I just found out that project scarab's donation was a Bates billet chain tensioner

I will use this unit instead of my gen 2 with bates stiffer spring

Hopefully this will hold better

Attachment 20674

I recently got this bullet-proof bolt for ecotec's timing chain guide.

Might as well install it, while fixing the chain tensioner issue.

Attachment 20195


Attachment 20196


Attachment 20197

Bates timing chain tensioner doesn't have the ratchet mechanism, stock unit has one.


also

Bates spring tensioner vs stock unit

Attachment 20194

Back to tuning?

Can't believe I missed this thread being here . Definitely a cool setup for the secondary fuel system from what I've seen. So you ditched the Nx kit for a custom fuel cell ?