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228/230, big stick for a 4.8L. I question why in the world go with a 112 LSA cam though.
Quote:
Originally Posted by yurs78
Exactly! Just think if they took a few seconds and spec'd out a good cam. You can find a lot of power with the right combo. (not that they needed anymore)
Running twins like that allows the use of a cam with a tighter LSA. The drop in back pressure from having the second turbo there reduces the potential for flow reversion by a LOT.
The fact that the cam they chose kicked some *** isn't even debatable
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Jake
1994 Geo Metro...the warpig
2004 Silverado RCSB...with power adders
You know theres some smug engineerings over at GM after reading this
rightfully so
I dont understand how 75s took them that far, seems like they would need injectors twice as big...unless they are running 300psi fuel pressure.
That's what I was thinking! Aside from the sheer amazement at the power and the boost they threw at it. I'm at 88% IDC with my 75#'ers on E85 and a 3.0" pulley and don't go above 6600.
That whole magazine rinks of BS, 75lbers wont even support that power level, need somewhere around 85-100lb injectors. If the 450 horse naturally aspirated is from the 4.8 and not some other engine, then the whole article goes down the drain, so yeah i dont think so.
That whole magazine rinks of BS, 75lbers wont even support that power level, need somewhere around 85-100lb injectors. If the 450 horse naturally aspirated is from the 4.8 and not some other engine, then the whole article goes down the drain, so yeah i dont think so.
The injectors can be bandaided somewhat with high fuel pressure like mentioned, and the lesser load of a engine dyno might contribute to the smaller injectors being acceptable some.. I see the mentioned bigger fuel rails, any mention of the rest of the fuel setup? Does make it a little hard to swallow seeing just the 75s mentioned.
Now the n/a argument, 450n/a on an engine dyno would probably be around 370ish thru a 60e auto. So that means could a 4.8 with 7/8 headers, fast intake, good heads, and no accessories at all be able to peak @7k rpm with that cam and make 370rwhp. Imo yes it could be done..
I think everybody is overlooking what i would call a pretty impressive top end with that intake and heads. Everything ive seen with a fast and boost has shown really good numbers and performs really well, this is no different..
Do this on a completely stock 4.8 with no upgrades and i think they barely break the 1k mark..?
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03 Silverado SS -arrival blue-
BUDHAYES3- Gone but not forgotten
I'm skeptical. The injectors are too small and it's an engine dyno. I read a lot of these engine dyno writeups and they always seem liberal with the numbers. At any rate, it's a very impressive project.
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'00 Sierra ECSB, 9.9:1 forged 6.3 (383ci), Magnusen 1900 (2.8" pulley, 10psi), I.W. 8-rib, Holley 90mm, 228/236 551/551 116, Crane 1.8 rockers, Patriot 243's, 4L80E, Circle-D 2600, 4" ARH exhaust to go on in the spring
If the 450 horse naturally aspirated is from the 4.8 and not some other engine, then the whole article goes down the drain, so yeah i dont think so.
You don't think a heads, big cam, Fast intake, large primary headers, no accessories, electric water pump, 4.8 can put down 450? Take 20% away for drivetrain losses and you would see ~360 rwhp in a vehicle. Seems legit to me...
As for the injectors, I don't know...
Edit: skolman beat me to it, lol
Last edited by Beatdown Z; 07-19-2011 at 06:15 PM.
Reason: boats & hoes
The fuel injectors come down to fuel pressure. Those 75lb's quickly become 100lb+. I run my 80's at 94 and would go higher if I had a stronger pump setup to support it. I would say they have more then enough pump suppling pressure/volume at the test stand.
As to the power, here's another one, stock crank and rods. It does have pistons though, ended up making 1342HP/928TQ at 7500rpms.
This is a 4.8L rod on the left, 5.3 mid, lq9 on end. Sure hell doesn't look like a 1300HP rod. I would want to be wrapped in armor if I pushed my truck to those levels for a 1/4 pass.
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2004 GMC RST: TMS Iron 347/S480/4l80E
Old best 4.8L/S475: 919HP/880TQ
Quickest/Fastest 4.8L Truck 10.17@134.26 (retired)
Hmmm small displacement has proven good turbo hp, you also have to consider they are running 118 octane which should in turn lower duty cycle from needing less gas and having a cooler combustion, someone please correct me on this if im wrong....But im blown away myself on them achieving that on those injectors id myself like to know how much fuel pressure they were running
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1995 RCSB Chevy 408, 9:1 Cr, Callies Crank/Rods, Diamond Pistons, TFS 225's, Garret 91mm, AMS1000, Alkycontrol, KB Hot Parts, Custom Intercooler & Piping, Ladder Bar, drag springs & QA1's, Full Manual Th400 & T-Brake, Circle D, Full Spool 3.42, Champion Forged Wheels, 5" DP w/ Magnaflow, 10 Point Chromeoly Cage http://Build Thread: http://performa...d.php?t=469809
Best Passes: http://www.youtube.com/watch?v=s7Uir...ure=plpp_video
