ive been throwing the idea around about boosting my 7 after i get my portwork done in the future. i have a buddy that welds and makes custom intake and exhaust manifolds for hondas and wants to make some for my car when i do this project. i dont know jack crap about turbo sizing but i figured a t04e or something of the sort would be sufficient with a street port or half bridge. will be carbed and a blowthrough setup. any recommendations for another turbo or anything? like i said the manifolds will be made according to what turbo i get and the mount it uses so using a turbo off of a t2 isnt that nessessary...

here is around what im looking at. good or bad?
http://cgi.ebay.com/ebaymotors/T3-T4...Q5fAccessories

 

Way too small on the hot side. On a rotary, especially a ported one you will want at least a 1.00 exhaust A/R on a t3 footprint, or a .80-1.00 A/R on a t4 footprint. Spend some time in the Single turbo setion here, a lot of people are having great results with cheaper Holset turbos, hx35/hx40.

Isaac

 

alright man thanks. im used to turbos on my powerstroke and its pretty much straight forward. bolt the biggest one u can on there and hope it clears up the smoke and lowers ur egt haha. ill look into something along the size u recommend and read on the single turbo section

 

i knew the holset hx35 and 40 sounded familiar. thats what alot of ppl run on cummins diesels. now my question is how can a 1.1l rotary flow enough to spin that size of turbo? the one on my powerstroke is a 1.15 on the hot side. im confused because that turbo is massive

 

Rotary's Spite out like 3 times the amount of a engine the same size. So think of the 12A as a 3 liter v6 or I6 or something along those lines. Theres a lot of exhaust comin from ur engine. Ull be fine with a big turbo. And once you get in boost theres even more comin out. Ive seen a turbo the size of my head on a 13B Bigger than whats on a Semi. And they are 12 liters. He is pushin 40 pounds of boost. 900 HP

 

ive been reading in the single turbo section a good bit since im stuck at work on nights. looks like im gonna try a hx40 holset turbo as they are kinda cheap and ive seen them go through hell and back on a 5.9 cummins with 1600 degree egts. its gonna take a few months to get all of this going but just trying to get it all lined up early

 

The combustion chamber is very small, (volume-wise) compared to a piston engine. The exhaust gasses are still expanding and burning as they come out. There is a ton of moving air.

 

on a 12A?!?!

no way, the first turbo mentioned would be much more responsive on a smaller engine. But I'd try to put something together with an internal wastegate because a 12A won't have the boost control problems of an FD. HX40 on a carb'd 12A. Screw that. Then you have to do all the plumbing and buy an external gate etc. The ports on a 12A are small and the displacement is less than an FD, plus he doesn't have some fancy twin scroll manifold and electronic spark advance to improve spool and increase safety.

HX40 on a 12A--come on man, a 400whp carb'd 12A ?!. HY35 would be big enough if you really wanted to go "big". Don't apply FD turbos sizing rules-of-thumb to a carb'd 12A. I'd get a TD05-16G (there are a few out there) and fab up an internally wastegated manifold for that. It will be so much simpler and more fun for the car. If you put an HX40 on a 12A first gen:

1) you'll have to deal with a lot of lag
2) you'll have to worry a lot about blowing it up
3) if you can keep the motor held together (and I'm not saying you can't), your clutch won't hold and/or you will grenade the drivetrain. My rebuilt T2 tranny can barely hold a Garrett T67 at 16psi and that's close to an HX40 in size.

A 1st gen wasn't engineered for anything close to an HX40. If you go that route you do so at your own peril. The original 12AT was rated at what, 160 crank horsepower?

 

i was looking at the more smallish turbos like the first one i posted until someone said i needed way bigger. i couldnt imagine spooling a turbo the size thats on my powerstroke with a 12a. and hx35 isnt quite as big, is internally wastegated and i can pick one up decently cheap because they come stock on alot of the older cummins diesels. as i said all of the piping and exhaust manifold is going to be made from scratch so i dont care what flanges it has. also the exhaust flange already accomodates the wastegate and has a 3inch vband clamp to run the exhaust off of. i just want proper sizing because im not too keen on reading compressor maps and all that bs. and yes it will be carbed through a weber more than likely and will end up with a large street port.

 

So, based on all the information - go with a stock S5 Turbo. Save money and time. It will work fine, and support over 300whp.