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Old 07-18-2016, 12:31 PM   #1
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Location: Redmond, WA
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502 Twin Turbo

I'm in the process of building a dyno hero, with no immediate intent of putting it in a car.

Long story short I had this motor in a '69 Camaro with the intent of putting an F2 supercharger on it, but then decided I wanted it to be a daily cruiser, so stuffed an LS3 in it.

Now I have this 502, all forged, with Trick Flow 340cc rect port heads and a Hogan sheet metal short-runner intake, Scorpion roller rockers, BigStuff3 computer, MSD DualSync, 85# Siemens injectors, and some other decent parts.

I want to put it all together with twin turbos and see what it'll do on my friend's engine dyno.

So, I ordered two GT45 eBay turbos and some stainless exhaust manifolds. My next decision is how to intercool it... any suggestions?

The bottom picture is about 10 years ago, so I painted it all Chevy Orange just to clean it up. And because I like tall orange valve covers! It could use a lot more cam (stock ZZ502 cam right now) but I don't want to tear it apart if I don't have to.

I have a 4" throttle body and the turbos are 2.25" discharge, so I've got to bridge that gap somehow also.
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1970 GMC Sierra Grande Custom Camper - Built, not Bought
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Old 07-18-2016, 01:37 PM   #2
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Re: 502 Twin Turbo

That cam will probably get along well with those turbos. I think between the cam and reasonable sized turbos (for a 502) you will have a real, tractable monster on your hands.
1968 C-10 Suburban - Original 396/TH400
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Old 07-18-2016, 04:36 PM   #3
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Re: 502 Twin Turbo

I would suggest an water/air inter-cooler.

When I was going to go twin 67's my plan was to use two 4 1/2" thick 16"x10" cores inside an alum sheet metal box. The cores would be standing 10" tall inside the sheet metal box with aprox 12" between them. This 12" gap would have an alum shield so you could put ice in from the top it with out damaging the cores, then close the lid. Each core would have it's own input and output but they would merge via a Y connector, 2x 2.25" in and single 4" out.
1/8---6.58 @ 105.92----5.87 @ 118.41
1/4---10.38 @ 126.97----9.24 @ 142.49
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Old 10-20-2018, 06:54 PM   #4
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Re: 502 Twin Turbo

502 tt combo is nice make sure to get a nice cam for turbos as it will work better for the set up. the stock cam will work but wont drive the turbo's like you need. i'm having a 540 twin turbo built now with 9:1 compression with twin 83 mm bullseye turbos. real tame on pump gas around 1200 to 1500 hp on the street. c16 in it probably around 2000. i will never put c16 in but my engine builder wants to tune for it just in case lol. anyways it is very doable probably a set of 80 mm's turbo's and a small decent cam from either bullet, comp cams, or howards cam's will do you right and be realy friendly to whatever driving you plan on doing. as far as bridging the gap that's just fabrication work. I have a plazma man intake with a 5" throttle body and both my turbo's have 3" that im going to fab together to go into the intercooler which is 4" in and out. Once i get back up to the throttle body i will just expand it to 5" hope this helps
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