I'm considering a trying a turbo. If I do this, I want to stick to my tried and true, bang-for-the-buck strategy. This means I fab/ mod my own headers, junkyard turbo's, and home tuning.

My first question revolves around selecting a turbo, size wise. I understand size vs lag/peak power compromise. But here is the problem; should I look for a turbo based on displacement&RPM only? Or on HP only (airflow=hp)? For example, my engine is 6.6 liters, and makes ~300 hp @~5000 RPM. With 2 turbos and 5-6 lbs of boost, I would expect it to make well over 350hp @ the same 5000 RPM. So should I look for two ~3.3 liter turbo engines for two units, or should I look for two ~200 hp engines to get 2 turbos from, regardless of the engines size?

The second question is about carburation and boost. What are the pro's and con's of blow through vs draw through? If I did a blow through, could I use a Vortech FMU to adjust float bowl presurizing?

since you are new here I will try to have mercy on you and save you from a possible lock check here Sticky: Turbo Stuff and this pre programmed



I made for you

Yeah, I already looked at those, but they aren't really TEACHING me what I need as much as they are throwing out EXAMPLES of build ups. Anecdotal information. I want to learn, so I can make my own choice. Thanks for reading my post though.
-Tom

Tom,

Tried and true. Turbocoupe turbos.

www.toohighpsi.com

check this guys projects out. He seems to use them on all his 351 turbo buildups and gets some mighty impressive numbers from it.

If you are going for cheap budget, these will work. No use in really spending the time trying to get to the bottom of the science behind it unless you just really want to learn everything about it.

Good luck.

Take a look - these guys always have that stuff for sale plus different A/R housings, flanges, BOV etc.
http://ubb.turboford.org/cgi-bin/ult...nt=;DaysPrune=

Not exactly either…

You size the compressor to work for the power output that you want at the boost that you will need to get it. It’s not as simple as picking 2 turbos that both move enough air to feed half the hp that you want, since typically, on a gas engine, turbos will get more efficient and move more air as boost goes up, but gas engines can’t always tolerate more boost. In other words, as the boost pressure goes up you can use a slightly smaller turbo to move the air necessary to make the hp.

You size the turbine side to spool with the ci and rpm that you want it to spool by (or if you look at it like the compressor side, you size it by the torque output of the engine, since that depends on the ci and rpm).

WRT to selecting turbos, I’d suggest that turbo stuff sticky and take a look at some of the links to turbo calculators and get a handle on what they’re doing/suggesting.

FWIW, with any reasonable amount of boost you should be able to see a 1/3 or greater increase in hp, so plan on making more then 400hp if you go this route.