cosmick

Ok, I've been active on TGO, under various names, since the first year, and I've been on the turbo forums for the last 4 years.
I've met Squires, when I had a shop in Orem, and his rear-turbo idea was real genius. Makes it emissions-legal, just replacing the muffler. Any cat-back is legal.
He did a 4.8L Silverado 1500, and at 5 psi it didn't even need any PCM tuning. Passed emissions just fine. I was already impressed by the stock 4.8 in a Uhaul Silverado 1500, so I want to copy the Squires build, just not in a Silverado.
I got a couple of 4.8s, I still have one, it's been re-honed, it now has an '04 LS1 / LQ9 cam, the heads are 3/8 ported, I got a pair of '99 Z28 exhaust manifolds, and I'm putting it in my green Camaro, with a 4L80E and a 3.27:1 gear in a Ford 8.8" axle.
The problem with this one is most turbos aren't efficient at 5 psi.
Before that, I have a Vortec 7400 for my red Camaro, it will be a blow-through carbureted setup. Probably do 2 smaller turbos for it, again as after-cat. It probably won't pass emissions just for being a BBC, but with cats and EGR, it should run cleanly enough.
But first I have my '83 RX-7, with an L36 from a '96 Camaro, getting a GT3076R, 56-trim. It'll also be after-cat, because this car already passed emissions for a '96 Camaro. I won't cover that one in here, but since it already runs non-turbo, and isn't a daily driver, it should take the least work, and the least money, to finish. I'm just worried how it'll do with an L67 tune, I will never pay $400 for a dyno tune. $200, maybe. I can get the L67 tune for around $150 installed and driving.
I see you guys debating pipe routing and manifolds vs headers for twins in the engine bay, and I guess these cars don't have to pass emissions, or are race-only, but it's all silly since the Squires plan solves all of that. Just keep the stock cat-forward arrangement, if not the stock parts and pieces, and don't even need intercoolers blocking your radiator.
You can't sell kits, Squires patented that, but you can do your own. You don't have to buy his kit, you just have to cut and weld your own pipes. If you ask a shop to do that part for you, then Squires could sue them, so buy a welder and practice with it.
I was professionally trained to MIG weld, but I then learned stick welding on my own, and have a cheap stick welder in my garage. The only other thing you need is an angle grinder, like a 4.5" version. Something you can use one-handed.

TurboedTPI

As the owner of an L67 powered Buick Regal, I can tell you, your going to want a better tune than the stock L67 tune. There is alot to be gained in a better tune alone. Plus, the stock injectors (36lb) are good to about 300whp, so you going to want bigger injectors and that alone needs to be addressed in the tune. Turbo 3800's can make big power, but you'll need some tuning to get there. I tune my Regal myself with hptuners. Its still an M90 car, Im guessing im in the 330-350whp range. Its a very fun daily driver and still manages 30+mpg on the highway. Id like to go turbo one day, and really hurt some feelings. haha

Orr89RocZ

iTrader: (20)

Becareful with cats on a turbo car. Running rich as turbo motors do and the Backpressure can cause the cat to operate at elevated temperatures and may eventually cause them to fail. Any particles that break off can end up damaging the turbine.

I dont know how long it would take for that to happen. But it is a concern

And once again you need a tune a turbo car. Cant stress that enough. There is no way around it

And for anyone reading this, 400$ for a dyno tune is a steal, as long as they take a day to properly dial it in at all areas. Not a 3 pull tune and done deal

TurboedTPI

Turbos after the cats is a concern for sure. I did a turbo setup on my Jeep inline 6 a few years back. Others did as well and Banks came out with a kit, the problem is the last few years of the 4.0l engine, they added cats right off the manifolds and the turbo was located after the cats on the other side of the engine. Mine didn't have the pre cats luckily, because it was older, but some of the guys with the newer Jeeps had the cats come apart and take out the turbos. Personally, I'd never put a turbo after a cat for that reason.

TurboedTPI

It was a fun jeep that's for sure.

Orr89RocZ

iTrader: (20)

The cat on my rear mount 305 tpi build actually helped keep echaust hotter and increased spool energy. When i deleted it, i had to go to a smaller turbine housing and it still didnt seem to be as responsive

And i recommend an intercooler or meth for any boosted pump gas deal regardless of rear mount or not. It still heats up

86CamaroDan

ANYTHING that is calibrated for a NA fuel map WILL NEED to be tuned no ifs, ands or buts about it. I went from NA last year to a blower this year and it WILL need more fuel everywhere or its gonna run lean across the entire board. Tune it yourself or take it to a shop, the choice is yours, but saying your gonna run it on a stock tune is foolish. I had to almost double my acceleration enrichment just to get it safe, never mind correct.