turbo and TBI fuel system

[dusterbd13]

OK, im odd. i know this, and im OK with it.
im looking at doing a throttle body injected motor with a rear mount turbo, much like the STS stuff thats out. only doing it on my own, and on my beater. were not talking about making crazy power, either, just some more than it currently has. lets say about 5lbs of boost. if this works, when i do the TBI small block in the vehicle, ill incorporate a turbo into the mix from the beginning.
i know that with the MAP sensor setup to read vacuum, it wont work too good with boost. what i was thinking was that i could fool it by taking a reading at the inlet side of the turbo to provide the vacuum. will that work? also, i was thinking about using a 3rd injector on a boost referenced switch so that im getting some extra fuel starting at about 3 pounds.
all this is actually on an 88 2.8 S10 that is being built for the GRM challenge.
please, let me know what you think. im seriously considering doing this if i can figure out the fuel system. the mounting and plumbing of the turbo wont be hard, just the management side.
thanks
Michael

[LS1NOVA]

I know your trying to keep the cost low but check out a Megasquirt controller from DIYautotune.

[dusterbd13]

ok, other than laptop tunability, what will the megasquirt get me that burning a new chip wouldnt?

also, any ideas on the MAP?
Michael

[Kenova]

You can get MAP sensors that read boost, but I'm not sure how that works with your computer.
Rather than using a third injector, you could just use a pair of bigger injectors in the throttle body, of for that matter, a throttle body off of a 305 or 350.
There would be a lot of tunning involved to get your PROM chip burnt with the correct programing. I think a programmable computer would save you a lot of head aches and time in the long run.

Ken

[Turbo67camaro]

I haven't done it myself, but I've researched the same stuff.

I'd be inclined to use a 2 or 3 bar MAP sensor that reads boost, since boost applications are what they're designed for. Tuning will likely be easier and better if done that way.

Also, aim for a total HP, to figure out how much fuel requirements are.

STS says, in their applications, that the amount of HP per boost psi varies, but 25 HP per PSI is typical. Note: A lot of variables affect how much HP per PSI you get.

So, if you start with a 300hp motor, with 5 PSI of boost, if you're able to get 25 HP per PSI, then your motor will make about 425 HP. Make sure the TBI unit you're planning on using can delivery enough fuel for 425 HP.

By the time you get a good Turbo, good fuel system (capable of enough fuel), computer, and all the highly recommended sensors, gauges, and controls, it gets pricey. Budget it all out before you jump.

I'm eventually going to install an STS rear kit and a capable fuel injection kit, and all the associated controls, but that will be in version 2 of this project, since all the other costs of the project have exceeded my short term comfort zone.