5.3 build
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5.3 build Building a 5.3 .030 over 10.5 to1 tbss intake cam motion titan 2 ls truck camshaft 212/220 -122+4 lightly ported heads #862 headers cold air stock converter Question what size TB you would use have read 5.3 can't use any more air than the stock 78mm and what size injectors.Is there someone who makes a better 78mm tb thanks.
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Building a 5.3 .030 over 10.5 to1 tbss intake cam motion titan 2 ls truck camshaft 212/220 -122+4 lightly ported heads #862 headers cold air stock converter Question what size TB you would use have read 5.3 can't use any more air than the stock 78mm and what size injectors.Is there someone who makes a better 78mm tb thanks.
92mm...The TBSS manifold opening is 90mm might as well use it. I am using GM 50lb flex injectors and running E85. It's worth about 15-20hp over 87 octane and a lot cheaper than 93. Smells a lot better too. Pretty easy to install a flex sensor and flash a 2002 OS on the 411 PCM stuff and have the ability to run E or pump.
Last edited by kinglt-1; Feb 16, 2023 at 09:47 AM.
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From: Grand Rapids, Michigan
You don't necessarily need different specs on your cam to run E85, but you could run up to 13.5:1 compression with it N/A. I wouldn't hesitate to run 11.5:1 on 93 octane with an appropriate DCR, so you'd be leaving power on the table only running 11:1 if you're going to strictly run E85. However, if you want the flexibility to run either, stay around 11:1 . I'd run the TBSS throttle body all day. My donor vehicle for my 5.3 build was a Saab 9-7X with an LH6 and it came with the TBSS intake and TB from the factory. If GM felt it was appropriate to run it, I don't see any reason to step down in size.
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Verdad Gallardo I just have a stock replacement Delco. I don't remember off hand the size but the Yukon pumps were said to be good up to 450-500hp on gasoline. I don't believe the pumps have a issue with E85. The main thing is if you add any fuel line to your fuel system make sure it's PTFE.
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From: PDX-OR-USA
You might,, want to upsize the fuel lines, if your replacing anyway, If you do it with hard line, its not much price difference,
Because of the variation in head pressure the pump will see I would use a return regulator so the pumps) don't dead head in traffic or when sitting idling.
Just my 2 bits.. I'm not a fan of high power fuel pumps dead headed to a feed/supply only system, the pumps cook out from heat/load.
The return needs to be able to run most of the capacity of the pump combo resist cavitation and heating at low power levels.
Because of the variation in head pressure the pump will see I would use a return regulator so the pumps) don't dead head in traffic or when sitting idling.
Just my 2 bits.. I'm not a fan of high power fuel pumps dead headed to a feed/supply only system, the pumps cook out from heat/load.
The return needs to be able to run most of the capacity of the pump combo resist cavitation and heating at low power levels.
I have my main spark table setup for 87 octane, then when you add Ethanol it will add timing on top depending on how much Ethanol is in the fuel. The early flex fuel OS does not show a blend factor table but it's there we just can't see it. E50 will get about 50% of the timing that is programmed in the flex spark table. Unfortunately, we cannot adjust that like newer OS but it's not that big of a deal.
Mine is just stock compression. Wasn't too concerned about compression since I was going with a small cam and I basically use my Yukon to tow small loads(boat/car). The dynamic compression is still decent with this mild cam even at 9.5:1, so its still responsive down low. And I wanted to be able to throw some pump **** in if I am in a pinch out on the road and no E pump near by. I probably should have bumped it a point.
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From: Euless, TX
One of those regular cabs is on my list to build soon. However I am going south of the border when I build it. L31 based engine. I want to use a 415 or 427 small block and make it look factory under the hood. Most casual observers will never notice the 2 extra cylinders.