I built a budget 454 engine with a BorgWarner s475 with a t6 flange and 1.32ar.Im wanting to drop in my 496 with 8.5-9.0to 1 compression and wanting to upgrade to a different turbo.Im wanting something that will basically bolt on to the t6 flange and hopefully use the current 5 inch downpipe.The s475 has the 5 inch ex exit so hoping for a bolt on.Im only looking to make 800-900hp at the crank so don't have to go crazy on the turbo just want something that will achieve this and be a quick swap

 

What size turbine and ar you looking to go up to?

 

Jeremy im not sure what to use that's why I posted.I have heard maybe a s480 1.32ar 80mm but not sure if that will work on a 496.Im not looking to go much over 5-5500 rpms and just trying to hit 800-900 at the crank so not massive goals.Just need to find a turbo that will do it on the s475 t6 platform I have currently

 

Im not sure what your budget is but if your looking at Comp, their CT5X series would fit what you have, they have open and divided T6/5" vband ar options. They are the lightest T6 frame turbos on the market with billet aluminum center sections.

http://compturbo.com/products/turbos/ct5

 

what are you making for hp now? boost ? rpm? pre turbine back pressure?

 

this is just me guessing but im thinking high sixes.I had a 625hp before and this feels stronger.IM running 12-15psi of boost and shifting 5-5200.No idea about the pre turbine backpressure and how to measure.Would normally do one of the caculators with my times but we are in winter here and no track runs till spring..I have a lot to learn that's for sure..Its a 454 mild cam,aluminum intake some very slight head port,cleanup.300-350hp at crank..All numbers are crank and not rear wheel hp

 

pre turbine back pressure, drill and tap your cross over tubing (pre turbine) buy a brass fitting and a little copper line maybe 12-24inches (enough to dissipate exhaust heat ) and hook a boost gauge to that. so if you are running 15psi of manifold pressure and 30psi of pre turbine pressure you would have a 2:1 ratio

the purpose of this is to see if the turbine is to much of a restriction/to small

 

wow never new this.So do you drill at the merge pipe where the 2 pipes come together or off of one of the banks coming from engine.My pipes come together and pretty much go straight to merge pipe..Also when I get the ratio what is a good ratio to have...I have heard some on here talk about the back pressure but never understood it..I really appreciate your info and helping me to understand this alittle better,I put a pic in this response so you can see how I joined the pipes together..thanks again

 

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ONce again I appreciate the info.I know the backpressure is very valuable info to know and will do as suggested.I would like to understand what im looking for as far as a proper working condition with the turbo.Am I looking for a certain ratio as far a 2to1 etc on the backpressure and when do you know your in trouble..thanks again this is very interesting info

 

That is absolutely horrible waste gate angle by the way.

 

What is the 496 combo? They make a 1.58 a/r for the s400, but the turbine wheel is going to limit you with that much cid, and a decent head/cam. The turbos for the big motors get expensive, and twins almost become a cheaper option. The Garrett tv8101 was a common turbo for big cid, its old, and getting hard to find, but there are still some out there.

 

sell the s475 and put on a pair of ebay gt45s

 

from the looks of it your hot side would be easy to change into a twin setup

 

I would drill and tap in the straight section after the merge

gate diagram may help if your getting boost creep ,, if not its working good enough for now

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I just drilled and tapped a 1/8npt hole in the exhaust side cover right above the flange. Then used a compression fitting to ~2' piece of 1/8" brass tubing to a pressure gauge that holds the highest pressure reading. I wouldn't go with a new turbo (unless you switch to twins) until you see what your S475 does on the 496. I made over 800rwhp with a plain S475 on a 338 @ ~17psi. I would fix your w/g placement angle..your probably getting boost creep now.

 

thanks guys I didn't realize how far off I was on the wastegate angle.I will fix this over the winter since we are down till spring.I thought I might try the 475 on the 496 but just figured the engine was way to big for it.I will do the ex pressure to see how bad it gets

 

Its 8.5-9.0 compression with a eagle forged crank,eagle 6.385 rods,oval port 781 casting heads with 2.25/1.88 valve with some porting team g intake and haven't bought cam yet but will be around 590-600 lift on a 114 lobe separation.