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Looking to add a rear mount BW475 to my ls 370 swapped 85c10. Really like to know what hot side size pipe would be best off my headers as well as size of cold side coming up to the intercooler. Its a TMS 370 that made 360rwhp and would like to start buying little by little till I have all the components and dont want to buy the wrong turbo,WG,intercooler and ect. I been reading a ton but still unsure what would work the best without killing the bank and still be a good street truck with a trip to my local strip on occasion.
What turbo? s475 or 480? What AR would be best as well? A decent intercooler? Like to put down around 600rwhp if possible without blowing up this TMS engine that i might add is a real nice motor. Any help or advise will be greatly appreciated.
I read all the stickies and been lurking on turbo forums, i just need some advise besides what i already know. I dont want to buy things and regret it later. This will be my first turbo and i want to get it right. Whats wrong with some good sound advise from somebody thats been down this highway before.
Did everyone catch this is a rear mount turbo? Not the same stuff as a typical front mount.
OP what size is your current exhaust and what are your hp goals?
Current exhaust is 2.5 inch,, HP goals about 600rwhp give or take and yes this is a rear mount because of the way i have a high mount AC compressor. So basically after the headers it will be about 3 foot to the turbo and a long distance back up to the cooler.
Current exhaust is 2.5 inch,, HP goals about 600rwhp give or take and yes this is a rear mount because of the way i have a high mount AC compressor. So basically after the headers it will be about 3 foot to the turbo and a long distance back up to the cooler.
I would highly recommend finding some factory exhaust manifolds and get rid of the headers. You'll also want to wrap all the piping back to the turbo as those 2 things make a huge difference. Also there is some good info on here about a quick spool valve that makes a big difference by using a divided turbine housing. As far as turbo size you'll need something in the 72-76mm range with a .81 or .96 a/r. Typically a smaller a/r is used for a rear mount setup. I would suggest you search on here for "zombies rear mount turbo saga" thread as well as a guy named Josh with a CETA TA that was rear mount. Lots of good info in their threads about what works and what doesn't.
Why not headers? If the exhaust is supported properly, thick metal enough to be wrapped (very high quality, thick enough stainless) headers would be far far ideal to OEM manifolds.
It will cost more but this is one place you can get away with headers (rear mount) pretty easy. That could be worth several PSI of drive pressure, who knows, 20-50 horsepower on a 600 horse setup. With a properly positioned, shaped Y-merge (tuned length) it could be worth even more. But thats fabrication/testing city so forget I even said that.
Why not headers? If the exhaust is supported properly, thick metal enough to be wrapped (very high quality, thick enough stainless) headers would be far far ideal to OEM manifolds.
It will cost more but this is one place you can get away with headers (rear mount) pretty easy. That could be worth several PSI of drive pressure, who knows, 20-50 horsepower on a 600 horse setup. With a properly positioned, shaped Y-merge (tuned length) it could be worth even more. But thats fabrication/testing city so forget I even said that.
It has been proven time and again that stock manifolds are better than headers for a rear mount turbo setup. Perhaps you should research the threads I listed in my last post. Getting a rear mount turbo to work is all about maintaining high exhaust gas temperatures to get the turbo moving. Headers are notorious for cooling the exhaust, and therefore dont spin the turbo as well. People have picked up SIGNIFICANT spool time (i.e. 500rpms or more) by switching back to stock manifolds.
Why not headers? If the exhaust is supported properly, thick metal enough to be wrapped (very high quality, thick enough stainless) headers would be far far ideal to OEM manifolds.
It will cost more but this is one place you can get away with headers (rear mount) pretty easy. That could be worth several PSI of drive pressure, who knows, 20-50 horsepower on a 600 horse setup. With a properly positioned, shaped Y-merge (tuned length) it could be worth even more. But thats fabrication/testing city so forget I even said that.
Because almost all the swap headers for these trucks are cheap thin stainless welded by a chinese 12 year old. They will crack under normal use and even quicker if you wrap them.
OP, save yourself a bunch of headaches and put some factory manifolds on it.
Because almost all the swap headers for these trucks are cheap thin stainless welded by a chinese 12 year old. They will crack under normal use and even quicker if you wrap them.
OP, save yourself a bunch of headaches and put some factory manifolds on it.
I mean to that end, I would say to take advantage of the tons of under hood room that's available and mount the turbo in the engine bay. That will avoid a lot of headaches and hassles and perform better.
Plain jane headers on this vehicle here, rear mount turbo....true street car. I filmed this a few weeks ago, would have went faster..... but popped a headgasket around the '1000 mark. Car seems to run fairly decent, wouldn't really call it slow. Lt1 car btw.
I used to literally sit in the engine bay on the inner fender when I wrenched on my 77' BBC truck.
There outta be PLENTY of room for activities under that hood lol.
If you want to "to do it right the first time" then why do you want to do it with headers and rear mount?? I've been there... I had an STS turbo on my truck for 2 years... Hence why I build a front mount and sold the STS. Night and day difference in daily driving and spool times. Headers have a TON of surface area vs stock manifold that dissipates heat (not what you want to do to a turbo). That's why they are far WORSE on a rear mount setup.
BTW, I know a guy who can build a turbo manifold that will fit that truck.
07-10-2017, 04:36 PM
Need a little buying advise 
