Fuel injection, 1999 Chevy Tahoe stuff... Would like a little help
04-20-2018, 01:52 PM
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Fuel injection, 1999 Chevy Tahoe stuff... Would like a little help So....kid that works for me buys my 99 Tahoe and kills the engine a month later. It's now known as the "oil filter cannon" as he goofed and bought the wrong filter.
kids...
He saves his money and over the winter we pull this thing and go through it. Turn it into a 383. Keep the Vortec iron heads, throw some cam at it (Comp "boat" cam, .540" lift setup to pull stumps at 1k-6k rpm.) Roller rockers, some headers, MSD the snot out of the ignition, and not much else. Pretty much a warmed up "gopher motor". When it comes time to decide fuel delivery I encourage him to look at the MSD Atomic. I know a local shop that's installed a lot of them and they've had good luck. My reasoning was/is that with 10:1 compression, the cam, headers, and the bump in CID the OEM TB spider injection that came on the truck was just going to have one hell of a time managing it. So that's what he/we did.
Engine in the truck now and it makes the power he's after. Its got a fair amount of "onion" in it. I'd guess it to be in the 420-450 range for flywheel hp output. Plenty for a 17 year old kid.... Do a 10mph roll, stab it, and it'll bust 32" tires loose all day. Starts, idles, goes, etc.
The tranny has been a little more work as the thing is struggling to figure out what the engine is doing. So, he bought a controller for it and were working on that.
Here's the scenario leading up to my question:
There's a neighbor of his who also dabbles with cars. Big cid TT stuff. He is telling this kid that it was a complete waste of money to buy the MSD fuel injection. He swears he can/could of made that engine make the same level of power with the stock OEM GM fuel injection. The TB with the injector spider under the manifold.
I am just not seeing that as being possible. Injector duty cycle, trying to manage the increase in displacement, the cam, blah blah.... If this were so why where the "compucams" from back in the day so pitiful? The old snake oil trick of sending in the OEM brain to be "tooned" was a gimick. Burn a diode to lock into cold start so it fattens it up...
Long story short the kid is now a little irked thinking that I shoved a $1200 fuel injection setup down his throat for no reason.
If I am wrong, feel free to run me through the tree chipper. I don't think I am but I do not profess to know everything either.
Thoughts encouraged and thanks.
kids...
He saves his money and over the winter we pull this thing and go through it. Turn it into a 383. Keep the Vortec iron heads, throw some cam at it (Comp "boat" cam, .540" lift setup to pull stumps at 1k-6k rpm.) Roller rockers, some headers, MSD the snot out of the ignition, and not much else. Pretty much a warmed up "gopher motor". When it comes time to decide fuel delivery I encourage him to look at the MSD Atomic. I know a local shop that's installed a lot of them and they've had good luck. My reasoning was/is that with 10:1 compression, the cam, headers, and the bump in CID the OEM TB spider injection that came on the truck was just going to have one hell of a time managing it. So that's what he/we did.
Engine in the truck now and it makes the power he's after. Its got a fair amount of "onion" in it. I'd guess it to be in the 420-450 range for flywheel hp output. Plenty for a 17 year old kid.... Do a 10mph roll, stab it, and it'll bust 32" tires loose all day. Starts, idles, goes, etc.
The tranny has been a little more work as the thing is struggling to figure out what the engine is doing. So, he bought a controller for it and were working on that.
Here's the scenario leading up to my question:
There's a neighbor of his who also dabbles with cars. Big cid TT stuff. He is telling this kid that it was a complete waste of money to buy the MSD fuel injection. He swears he can/could of made that engine make the same level of power with the stock OEM GM fuel injection. The TB with the injector spider under the manifold.
I am just not seeing that as being possible. Injector duty cycle, trying to manage the increase in displacement, the cam, blah blah.... If this were so why where the "compucams" from back in the day so pitiful? The old snake oil trick of sending in the OEM brain to be "tooned" was a gimick. Burn a diode to lock into cold start so it fattens it up...
Long story short the kid is now a little irked thinking that I shoved a $1200 fuel injection setup down his throat for no reason.
If I am wrong, feel free to run me through the tree chipper. I don't think I am but I do not profess to know everything either.
Thoughts encouraged and thanks.
04-21-2018, 08:17 AM
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Modern EFI + DIS Hi Chad, YOU are the one who is correct, GO Modern.
I was a member of the inventor team, the team that created the DIS/EFI for GM Buick GN.
I too agree with the Make Something Dumb/My Spark Disappeared remark.
The GM "spider" injection is a constant flow into each cylinder UNTIMED to an OPEN Valve. This unit is also LIMITED in the fuel flow Volume thus NOT supporting the required HP of the "built" engine.
The Back/Back testing (bench) has ALWAYS found 25 HP on a 500 HP engine WHEN the "batch fire" injection method is changed to TIMED injection, timed to an open valve.
The OEM "spider" injection would only be poorer in fuel distribution.
Thus your good advice.
Lance, PanteraEFI.com
I was a member of the inventor team, the team that created the DIS/EFI for GM Buick GN.
I too agree with the Make Something Dumb/My Spark Disappeared remark.
The GM "spider" injection is a constant flow into each cylinder UNTIMED to an OPEN Valve. This unit is also LIMITED in the fuel flow Volume thus NOT supporting the required HP of the "built" engine.
The Back/Back testing (bench) has ALWAYS found 25 HP on a 500 HP engine WHEN the "batch fire" injection method is changed to TIMED injection, timed to an open valve.
The OEM "spider" injection would only be poorer in fuel distribution.
Thus your good advice.
Lance, PanteraEFI.com