Ross's extended city, easy entry Goblin- 06 SS/SC, NW Arkansas
- Thread starter Ross
- Start date
ncgoblin
Goblin Guru
I am at the range you are aiming for based on my mods and boost but I still need to dyno to get an accurate number I road tuned with about 35+ renditions with ZZP. Borg Werner S252 LSJ with FIC870SPLIT 870cc injectors. I am running 91 fuel at 23-24 psi. Anything above 24 psi will result in knock and duty cycle is upwards of 85%. I wish I would have purchased 1000cc injectors. I went with the Phoenix Performance Stage 3 Ceramic Clutch Kit and its a great feel.
After spending months with the boost controller its very difficult to dial-in the boost ramp in 1st ideally from the dig 19psi is about my max going into 2nd gear. The Cortex boost controller is awesome highly recommend. Going from the supercharger to turbo is finally at the point where I have reached my personal limit of control comfort.
Ross
Goblin Guru
Do you think you would be able to idle the engine if you were to use 1000cc injectors? I would be tempted to add a 5th injector and controller, if you want more fuel. That way you would still have your idle. Good to know about the Cortex boost controller. I still haven't purchased one, as I haven't found one to control twin charged engines. I have read that other twin charged engines just control one stage of boost.
ncgoblin
Goblin Guru
What concern do you have with single turbo over twin charged? Is it due to boost lag? The S252 has very minimal boost lag its noticable but for half second maybe 1s. Going with A2A cooler saves so much space by removing the intake and going with a SAAB intake. I would think twin charged would be another big challenge with tuning. Again my biggest challenge is not boost lag but controlling the boost going into second those 275s R88R rip out even at low pressure and 19psi. I bet the sound of twincharged is amazing though.
Ross
Goblin Guru
So how low of boost does your car make when going into 2nd gear? I had too little traction with an open differential, but the Quaife has made it much more controllable. Are you running an open diff? Would running a bigger/ported wastegate give your Cortex boost controller more range, and lower power going into 2nd gear?
The S252 is a pretty optimal turbo for our engines. I am playing with twin charging, just to do things differently. In the end it will be more difficult to tune, and weigh more, but there is a small chance it will have best of both a supercharger, and a ZZP Z57 turbo, which has slow response times. I have never made my own boost controller, but I may end up doing that. I have done 30+ microcontroller projects, so this is a possibility.
The S252 is a pretty optimal turbo for our engines. I am playing with twin charging, just to do things differently. In the end it will be more difficult to tune, and weigh more, but there is a small chance it will have best of both a supercharger, and a ZZP Z57 turbo, which has slow response times. I have never made my own boost controller, but I may end up doing that. I have done 30+ microcontroller projects, so this is a possibility.
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Rauq
Goblin Guru
I idle just fine with 80lb/hr injectors. A boost reference fuel pressure regulator is a must-have. My base fuel pressure is 42psi, so with idle vacuum it sits about 36psi.
I run a 2.9" pulley with an S257 and experience no lag. I haven't turned the turbo any higher than 20psi as I'm still on the stock fuel pump, although I'm in the middle of a 340lph pump install right now. I'm just running an AEM Tru-BoostX to control turbo boost levels.
I believe so far the limitation of the setup is the ability to dump supercharger pressure through the bypass valve. Even with the bypass valve fully open, I'm still seeing boost pressures at least 10% higher after the supercharger than before it. That's not really an issue if IATs are under control, which mine generally are (max 150°F on track in the summer), but part of the idea of twincharging should be making more power by unloading the load on the motor from the serpentine belt drive.
@Ross I'm willing to help out, and I apologize for not having been more forthcoming in the past. I was inundated for a time with folks asking me to basically build a twincharged setup for them, and it's one of those things that if you have to have someone do it for you, you're going to have a bad time. I'm not trying to gatekeep any knowledge, but I know you can handle it.
Do you have a plan to control the supercharger bypass valve?
I run a 2.9" pulley with an S257 and experience no lag. I haven't turned the turbo any higher than 20psi as I'm still on the stock fuel pump, although I'm in the middle of a 340lph pump install right now. I'm just running an AEM Tru-BoostX to control turbo boost levels.
I believe so far the limitation of the setup is the ability to dump supercharger pressure through the bypass valve. Even with the bypass valve fully open, I'm still seeing boost pressures at least 10% higher after the supercharger than before it. That's not really an issue if IATs are under control, which mine generally are (max 150°F on track in the summer), but part of the idea of twincharging should be making more power by unloading the load on the motor from the serpentine belt drive.
@Ross I'm willing to help out, and I apologize for not having been more forthcoming in the past. I was inundated for a time with folks asking me to basically build a twincharged setup for them, and it's one of those things that if you have to have someone do it for you, you're going to have a bad time. I'm not trying to gatekeep any knowledge, but I know you can handle it.
Do you have a plan to control the supercharger bypass valve?
Ross
Goblin Guru
Yes, I would like to control the supercharger bypass valve. Does the AEM Tru-BoostX know when the engine is in limp mode, and therefor stop boosting to save the engine? I am hoping to monitor the Chevy PCMs pulse width modulation (PWM) signal to the supercharger bypass valve so the boost controller knows when the PCM wants boost, as this will also respect limp mode.
I still need to source a boost reference fuel pressure regulator. I see that the supercharger bypass needs to flow more air... I'll have to look at porting it, and/or increasing the bypass butterfly valve.
No need for an apology, your build has been an inspiration. I have been slower than I want in my build, but enjoying the journey. Your experience is helping my build avoid future issues. There isn't many twin charged builds out there! You and DDMworks Ariel Atom are the only two I know of.
I still need to source a boost reference fuel pressure regulator. I see that the supercharger bypass needs to flow more air... I'll have to look at porting it, and/or increasing the bypass butterfly valve.
No need for an apology, your build has been an inspiration. I have been slower than I want in my build, but enjoying the journey. Your experience is helping my build avoid future issues. There isn't many twin charged builds out there! You and DDMworks Ariel Atom are the only two I know of.
Rauq
Goblin Guru
The TruBoostX only has a programmable boost threshold which, when exceeded, reverts to wastegate pressure.
I don't use the original supercharger bypass control solenoid. I don't think you can use it to achieve anything less than wastegate pressure from the turbo, which for me is still 11psi, so forgetting about it greatly simplifies bypass valve and wastegate control.
I think this is currently the greatest restriction in the bypass channel. Cutting and welding with some round/curved tube is on my list of considerations.
I don't use the original supercharger bypass control solenoid. I don't think you can use it to achieve anything less than wastegate pressure from the turbo, which for me is still 11psi, so forgetting about it greatly simplifies bypass valve and wastegate control.
I think this is currently the greatest restriction in the bypass channel. Cutting and welding with some round/curved tube is on my list of considerations.
comegetjoe
Goblin Guru
Sad Max
95Blitz
Well-Known Member
Not sure why put this pictures makes me laugh.
Ark :D
Goblin Guru
Ross just sees his garage, while everyone else sees his Wizard's Tower.
ncgoblin
Goblin Guru
Right now boost is at 19psi going into 2nd it probably should be closer to 17-18psi without losing traction. The transmission is setup with open diff the quaife may be my next future upgrade now that traction is an issue. The boost control with wastegate is not an issue its finding the sweet spot
. The cortex is programmed for boost by gear and RPM. When shifting into 2nd at 7k RPM the dip is 5-5500K RPM so that number should be also 17-18psi ideally all the way up RPM to 5500k in 2nd. If you are rolling into 2nd 20+ PSI throughout the entire RPM band is fine so what I should have is (2) boost profiles if I want to get the maximum boost in 2nd. My next tune will most likely be at 18psi all the way up to 5500k into 2nd and then 22psi for the remainder so I can have (1) profile because I do not get enough seat time to take the risk of sliding off the road
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Ross
Goblin Guru
We can rebuild him. We have the technology. We can make him better than he was. Better, stronger, faster.
It is a CNC machine. One day it will cut foam, for a front composite wing, for a goblin.
Glad you got a laugh out of it, although that is not the intent of posting it here.
I logged my progress in my build log. What were you expecting in my build log?
Thanks! If I get bored and need something to do, I just walk out to the shop, and something to do will find me.
Half build goblin. Half build CNC. Half cleaned shop. Half finished French cleat system:
Always find something to do in a shop. It's my happy place.
Oh good, I'm not the only one with umpteen half finished projects
Desert Sasqwatch
Goblin Guru
A man's shop/garage is his castle, err, man cave or something like that! It's my happy place too and it makes my wife happy I'm not in the house!
It's my happy place too and it makes my wife happy I'm not in the house!ah.b.normal
Goblin Guru
The lot of you have got me lusting after having a house again. Or at least a garage and flat cement! I sure hope I get some land bought this spring! Then get some structures built. I just want all my stuff in one county! Traveling full time and building my car isn’t compatible. But it has allowed me to work on other peoples cars!A man's shop/garage is his castle, err, man cave or something like that!
Markm
Well-Known Member
When you coming to west Tennessee? I don’t really need the help but if you happen to swing by I’d be happy to have you. I work by myself so me and the shop cat have good discussions
ah.b.normal
Goblin Guru
IF HRPT takes us to Nashville this year we'll be close! But that is presuming I am successful in bringing GOB-BALT to life! You know, life has a way of de-railing things. As I keep telling all who will listen, GOB-BALT will have to run and drive before I can modify it for speed and handling! Just now it's nothing but near scrap steel, plans, hopes and dreams. It would be nice if it works as well as the first Goblin!When you coming to west Tennessee? I don’t really need the help but if you happen to swing by I’d be happy to have you. I work by myself so me and the shop cat have good discussions