The Chupacabra. Quad Turbo LS Powered Vette Kart.
10-13-2017, 01:06 PM
#41
Burning Brakes
Thread Starter
4 turbo affords a few opportunities.
-I tried a pair of them with the internal gates, but the V8 overpowered the gates and I couldn't keep the boost down. Not an issue with 4 of them.
-Once I figured out I could use 4 small turbos with internal gates, the internals allowed me to keep costs down, as well as piping. No external gates to plumb.
-Less exhaust restriction compared to twins. Most turbo camshafts are based around the idea of negative overlap for when exhaust pressure gets higher than intake pressure. I don't have that problem, so my new camshaft has 9 degrees of overlap and sounds insane.
-The turbos are insanely efficient. Most of the time, for any given turbo, a smaller engine will allow more peak power because of efficiency. Low CFM, high pressure is usually more efficient than the average V8 guy running 6-8 PSI on a single turbo that is normally happier at 16+ PSI. Moving 1.2L each, these guys are at peak efficieny when boost is in the 20s, and HP/PSI won't stop dropping off until around 30 PSI or so.
-4 of them got your attention, didn't they?
-I tried a pair of them with the internal gates, but the V8 overpowered the gates and I couldn't keep the boost down. Not an issue with 4 of them.
-Once I figured out I could use 4 small turbos with internal gates, the internals allowed me to keep costs down, as well as piping. No external gates to plumb.
-Less exhaust restriction compared to twins. Most turbo camshafts are based around the idea of negative overlap for when exhaust pressure gets higher than intake pressure. I don't have that problem, so my new camshaft has 9 degrees of overlap and sounds insane.
-The turbos are insanely efficient. Most of the time, for any given turbo, a smaller engine will allow more peak power because of efficiency. Low CFM, high pressure is usually more efficient than the average V8 guy running 6-8 PSI on a single turbo that is normally happier at 16+ PSI. Moving 1.2L each, these guys are at peak efficieny when boost is in the 20s, and HP/PSI won't stop dropping off until around 30 PSI or so.
-4 of them got your attention, didn't they?
10-13-2017, 01:36 PM
#43
Burning Brakes
Thread Starter
8 would have been unreasonable. At .6L each turbo, they would've had to be very small. Instead of spending twice as much on turbos, I would have spent 6-8 times as much for small turbos, non-standard flanges, oil lines/fittings, etc. Then I would've had to run them very hard to make any power.
I've always thought about building a 500+ inch big block with 8 of these turbos on it, but I usually build 800+ HP complete setups on $3000 or less budgets, and I would've had 6-8k in the long block alone. If someone wants to sponsor it, I'll get it done before the first snow falls here in Ohio lol.
I've always thought about building a 500+ inch big block with 8 of these turbos on it, but I usually build 800+ HP complete setups on $3000 or less budgets, and I would've had 6-8k in the long block alone. If someone wants to sponsor it, I'll get it done before the first snow falls here in Ohio lol.
10-13-2017, 02:01 PM
#45
Burning Brakes
Thread Starter
When I had the stock cam, I was seeing positive pressure around 3000 RPM, and 9 PSI around 4500 RPM. This was actually kind of nice because most of my other setups would see positive pressure at 3000 RPM, 20+ PSI at 3200 RPM, and it feels like you were rear ended by a train. Not a good thing in a 2000 lb car on dry rotted tires.
The new cam and valve spring setup should give me positive pressure around 2800, with 10+ PSI by 3500 RPM.
The new cam and valve spring setup should give me positive pressure around 2800, with 10+ PSI by 3500 RPM.
11-03-2017, 11:37 AM
#46
Burning Brakes
Thread Starter
Not really much to post as far as updates.
I've set a 1000 HP goal for the stock 4.8 with quads. I'm still awaiting an engine dyno session, but other work has slowed me down. A 1:1 Power/Weight ratio in HP/KG is the ultimate goal, we will see.
I have arduino reading microsquirt fully. It is controlling the IAC motor, 2nd fuel pump, fans, and water/meth injection. Very cool setup that I have almost no money in. It also accepts 5v inputs and reads oil pressure and fuel pressure for me as well. It can also shut the ignition down for me in case of no oil pressure, excessive water temps, etc. I have probably $10 in the arduino setup. Cheap little things. So capable, too.The IAC control is a thing of beauty. It controls every bit as well as the OEM PCM for the 4.8 would. That and adaptive idle from Microsquirt give the big cam some idle control.
I imagine the car will be sitting down for about 6 months.
But when its done...
I've set a 1000 HP goal for the stock 4.8 with quads. I'm still awaiting an engine dyno session, but other work has slowed me down. A 1:1 Power/Weight ratio in HP/KG is the ultimate goal, we will see.
I have arduino reading microsquirt fully. It is controlling the IAC motor, 2nd fuel pump, fans, and water/meth injection. Very cool setup that I have almost no money in. It also accepts 5v inputs and reads oil pressure and fuel pressure for me as well. It can also shut the ignition down for me in case of no oil pressure, excessive water temps, etc. I have probably $10 in the arduino setup. Cheap little things. So capable, too.The IAC control is a thing of beauty. It controls every bit as well as the OEM PCM for the 4.8 would. That and adaptive idle from Microsquirt give the big cam some idle control.
I imagine the car will be sitting down for about 6 months.
But when its done...
Last edited by JoeNova; 11-03-2017 at 11:37 AM.
11-04-2017, 08:32 AM
#48
Burning Brakes
Thread Starter
The following users liked this post:
CVG323 (05-11-2018)
05-11-2018, 04:37 PM
#52
Burning Brakes
Thread Starter
The back of the car is light enough that I can grab the back bumper and scoot it sideways across my garage floor when I need the room. The 500+ lbs of downforce helps.
05-11-2018, 04:43 PM
#53
Melting Slicks
Active aero. The front of the wing is on actuators that tilt it based on speed, and force it vertical when braking.
The back of the car is light enough that I can grab the back bumper and scoot it sideways across my garage floor when I need the room. The 500+ lbs of downforce helps.
The back of the car is light enough that I can grab the back bumper and scoot it sideways across my garage floor when I need the room. The 500+ lbs of downforce helps.
The following users liked this post:
1993C4LT1 (06-03-2018)
06-02-2018, 09:51 PM
#56
Melting Slicks
Thanks for posting the update. Looks like it's coming along nicely. Just shared on Facebook with my post saying, move over Leroy the savage, Daddy's home.
