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The challenges - well, through a combo of MaAaron's and my efforts, got the car ready to start. Pretty anxious time for me to be honest. I bought a motor, the condition was not as good as I would have liked. I rebuilt the motor (my first) over the winter, feels like a really long time ago now and although I felt like I had done the job to the level required, you don't know until you know. I had a long time to forget about the fact that the motor would have to eventually run and plenty to keep my mind off it - there was just a lot to do. But now is the time, the electrical system has been tested to the extent it can, the fluids are in - cooling system vacuum bled - noting left to do but hit the button.
And.... The engine spins over, doesn't sound horrible on the starter (good) but struggles to fire up and when it does, it is not running right and quickly stalls out. Tried a couple times and went and felt the headers, bank 1 is cold, bank 2 is warm.
This started a path of troubleshooting that went from injectors to compression to finally the culprit - ignition. That sentence was days in real life. Why was there no ignition in bank 1, what caused me (and all my friends that were helping me) so much grief - A missing ground (of course it was). When I had assembled the wire harness on to the engine, I took some liberties with the routing that I thought would work better for my application. One of these liberties put a ground that I thought was for the bank 1 coils in a very reasonable spot to be the ground for the bank 1 coils. But, it wasn't. I quite literally finger stumbled on a ring terminal sitting on top of the intake manifold and immediately knew - I ****ed up. I quickly called MaAaon and told him what I found and he was on the phone for the first 8 cylinder start (the 2nd one was the video above). A great wave of relief to hear the engine fire to life and sound really good, had good oil pressure, isn't leaking any fluids and generally sounded pretty happy, mean, but happy - no weirdness.
But, that issue confirmed an issue I had seen when I was troubleshooting and the engine would run, kinda, self sustaining at least and the kill switch would fail to kill the engine. This was pretty weird because the main power electrical system is pretty straightforward. Today, we got that one figured out and resolved. For the nerds, (like me) here's what happened, the PDM is powered on from the kill switch enable, the kill switch sends 12V to a special input on the PDM specifically meant for this purpose, powering on the PDM, the display and anything set to receive power when the PDM is active. Upon PDM power up it enables a 12V output to the ECU turning it on, when the ECU sees 12V it provides a 12V switch trigger to the PDM to turn on the fuel pump and a ground trigger to power up the coils and injectors. All good - turn the kill switch on and the PDM and ECU turn on, the ECU controls the fuel pump so it primes and the engine is ready to rip. The problem was that fuel pump 12V trigger from the ECU to the PDM. See, the PDM has 2 special inputs that can receive 12V power and keep the PDM on, this can be useful for things that you want to run, but don't need the PDM display on for, like hazards or a fan you want to keep running after the engine shuts off. Well, my 12V fuel pump trigger went to one off these inputs, so despite the fact that the kill switch removed main 12V to the PDM, the 12V signal it saw from the ECU kept it running, thus, the engine kept running. So, I swapped the coil/injector trigger (a ground trigger) to that special PDM input and moved the fuel pump (12V trigger) to a PDM input that would not hold the PDM on and bobs your uncle - now when you hit the kill switch, everything shuts off and the really good part is the fuel pump control, something both Aaron and I feel is a pretty important safety control is still handled by the GM ECU - if its good enough for them to release on every LS Engine, it's good enough for me.
So that was a big win.
Other work that has been done - Aaron did my brake bleeding with his super vacuum bleeder thing (there are 2 people in this world I am cool with working on my brakes - they're both named Aaron, funny). While he did that I spent a lot of time under the car on wire / cable / line management. There is A LOT going on under the car. While I am content with how things are down there, its only for now. I anticipate I will need to put more work in when the car gets some use on it.
I adapted the brake booster lines to work with a combo of Porsche and GM parts.
Got the rest of the sensors in, the total sensor list looks like this:
AIM
Oil Temp
Coolant Temp
Cooling System Pressure
Crankcase Pressure
Trans Temp
Brake Pressure
Steering Angle
Random musings:
I almost killed Aaron, I told him I would tell you all about it, but I'm not going to - if I know you, ask me and I'll tell you. For everyone else, suffice to say - I'm a dumb idiot.
The car sounds mental with open headers, I loved the way my car sounded with the Porsche engine, it was the best part about that engine in my opinion, but this new engine with the big giant cam chop sounds bonkers.
I took this picture thinking about the absurdity of the cooling system, these are 3 huge radiators, like each one is probably big enough for a car on it's own. Porsche did not **** around with the Turbo radiators, they are funny huge. The front of the car is now a wall of radiators.
So, gating items to getting on track right now are down to 2. 1 I need to have an exhaust made for the car, target date for that is next Saturday. 2. The car needs to get on the dyno to have the ECU calibrated. I am still working out how soon I can make this happen, really hopeful it will no more than a week after the exhaust gets done. Feels really good to start looking at the track day schedule !
Lastly, THANK YOU Aaron, I know I've said it but I going to keep saying it, you are a huge contributor to where the car is, I would not be here if you had not volunteered so much of your brain power and energy, thank you man !
THANK YOU @Matt Romanowski - Your support is huge and I can't wait to run a trailbrake sticker on the car. If you all want to know Matt - I send him an email on Thursday at like 5:15PM, I say hey Matt, I just realized I need another temp sensor, can you send me an invoice ? Mind you, it's 5:15... Literally 2 minutes later I get an email from UPS with a tracker. I'm just going to say, If you want to know the type of support this dude will give - please, go buy some stuff from him.
I took this picture thinking about the absurdity of the cooling system, these are 3 huge radiators, like each one is probably big enough for a car on it's own. Porsche did not **** around with the Turbo radiators, they are funny huge. The front of the car is now a wall of radiators.
Hi Jason,
Looks like your car is coming along nicely. Congrats! You may wanna consider tilting the center radiator forward as is done on the 6GT2/Cup and all 7GT cars. You can install the OEM 6GT2 chimney vent on the back side of the center radiator and exhaust the air up over the hood which add front down force. You can see it done here. Exhausting the center radiator air under the car will add lift which you don't want. Cheers!
Last edited by powdrhound; 07-16-2023 at 06:58 PM.
We're aligned John and I have the chimney duct here.
It will take a moderate amount of modification to the 997 center rad setup to make it work. The 997 rad gets sandwiched in a plastic housing that bolts to the chassis, that housing has an integral duct that vents under the car. It is something I will endeavor to make work but not likely in the near term as I try to get the car done'ish and get it on track to see what really needs fixing.
Aero as a system is something I'm working on for the next or next, next iterations.
We're aligned John and I have the chimney duct here.
It will take a moderate amount of modification to the 997 center rad setup to make it work. The 996 rad gets sandwiched in a plastic housing that bolts to the chassis, that housing has an integral duct that vents under the car. It is something I will endeavor to make work but not likely in the near term as I try to get the car done'ish and get it on track to see what really needs fixing.
Aero as a system is something I'm working on for the next or next, next iterations.
Your splitter looks dope.
Excellent. I know a few 6GT3 guys that have done the 6GT3RS radiator mod which is what made me think of it when saw you pics here.
Last edited by powdrhound; 07-16-2023 at 11:33 PM.
Dyno day is set for the 31st assuming no disasters between now and then.
What will it make for power ? 6.2L, stock heads, dinky exhaust manifold, 2.5in exhaust with a x pipe resonator.
My guess is what I would be happy with - 400WHP, pretty sure its a mustang dyno, notorious for crushing dreams.
Take a guess, closest gets their pick of: PayPal a 6 pack of bud lite, a ride around the track if you’re local and down, a take off car part - lot of options there.
Dyno day is set for the 31st assuming no disasters between now and then.
What will it make for power ? 6.2L, stock heads, dinky exhaust manifold, 2.5in exhaust with a x pipe resonator.
My guess is what I would be happy with - 400WHP, pretty sure its a mustang dyno, notorious for crushing dreams.
Take a guess, closest gets their pick of: PayPal a 6 pack of bud lite, a ride around the track if you’re local and down, a take off car part - lot of options there.
are you getting it tuned also? that will make a difference for my guess!
07-15-2023, 11:35 PM
