LIPSTICK's 800hp first LNF compound turbo/engine build!
06-25-2014, 10:04 PM
#676
Senior Member
yes, we try to keep MAF and VE closer in numbers.
DI = 93 octane
PI = e85
once we go over 30psi fueling starts getting all wacky.
wecould increase pressure beyong 16mpa but we dont know how the pump will like it.
we dont have issues early, we have them late above 6k rpm
we have to figure out a way to curtail the PW up top. So far we are injecting 40 deg earlier and bump fuel pressure up.
we are currently spraying 20-24mS (wide open) or corn on top of that and yet we go lean and see STFT jack at the end. That should be a lot of power...but it not. The boost/power curve looks like a ruler on a 45 deg angle
When we tried 36psi, it made less power, jaged misfires. Primary PW was in the 60's for duty cycle ******* up the program.
We have the PW down to 8ms at 500 and 300kpa manifold using that pressure and some increase in injector timing got it to rev clean to 7500
We have t figure out how to fool the ecm into thinking there is less VE flow to prevent it jacking wild at the end when MAF deviates under by a wide margin.
when we increase rail pressure/timing we got clean high rpm pulls until we went up in boost then it comes back as we cross the magic threshold of 8ms on the DI
we can put about 15-20% PI ove the top of DI at any power level w/o pissing theEC off too badly by scaling the MAF.
we are at the max DI + 20% PI fuel right now.
if more fuel pressure get me more boost/flow before the 8ms lmit, then we can keep maf/ve offset the same at the higher flow/pressure.
DI = 93 octane
PI = e85
once we go over 30psi fueling starts getting all wacky.
wecould increase pressure beyong 16mpa but we dont know how the pump will like it.
we dont have issues early, we have them late above 6k rpm
we have to figure out a way to curtail the PW up top. So far we are injecting 40 deg earlier and bump fuel pressure up.
we are currently spraying 20-24mS (wide open) or corn on top of that and yet we go lean and see STFT jack at the end. That should be a lot of power...but it not. The boost/power curve looks like a ruler on a 45 deg angle
When we tried 36psi, it made less power, jaged misfires. Primary PW was in the 60's for duty cycle ******* up the program.
We have the PW down to 8ms at 500 and 300kpa manifold using that pressure and some increase in injector timing got it to rev clean to 7500
We have t figure out how to fool the ecm into thinking there is less VE flow to prevent it jacking wild at the end when MAF deviates under by a wide margin.
when we increase rail pressure/timing we got clean high rpm pulls until we went up in boost then it comes back as we cross the magic threshold of 8ms on the DI
we can put about 15-20% PI ove the top of DI at any power level w/o pissing theEC off too badly by scaling the MAF.
we are at the max DI + 20% PI fuel right now.
if more fuel pressure get me more boost/flow before the 8ms lmit, then we can keep maf/ve offset the same at the higher flow/pressure.
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.
Last edited by Terminator2; 06-25-2014 at 10:10 PM.
06-25-2014, 10:05 PM
#677
Senior Member
Thread Starter
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)
thanks Term, I appreciate it!
07-16-2014, 01:21 PM
#681
Senior Member
Thread Starter
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.
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.
Last edited by SKY888; 07-16-2014 at 02:35 PM.
07-16-2014, 01:45 PM
#682
Senior Member
Thread Starter
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!!!
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.
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!!!
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.
Last edited by SKY888; 07-16-2014 at 02:34 PM.
07-16-2014, 03:45 PM
#684
Senior Member
07-16-2014, 04:01 PM
#685
Senior Member
Thread Starter
07-16-2014, 04:06 PM
#686
Senior Member
07-18-2014, 04:09 PM
#689
Former Vendor
07-18-2014, 04:35 PM
#690
Senior Member
07-18-2014, 08:14 PM
#691
Senior Member
Thread Starter
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!
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!
07-25-2014, 02:33 PM
#692
Senior Member
Thread Starter
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!
Thanks to "project scarab" for providing the rods!
07-31-2014, 06:59 PM
#696
Senior Member
Thread Starter
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
I will use this unit instead of my gen 2 with bates stiffer spring
Hopefully this will hold better
12-03-2014, 07:15 AM
#700
Member
Join Date: 12-06-13
Location: Indianapolis
Posts: 241
Likes: 0
Received 0 Likes
on
0 Posts
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 ?