Rebuilding the motor w/ some goodies in mind

[66Sprint6]

Well, as many of you may know, I broke somethin or other on my motor recently and have reached the edge. Im sick of "fix it when it breaks" so its time to rebuild. My shop and I have been plannin a turbo project for some time now and this is it. We are going to rebuild the motor using Forged pistons and I believe the rest will be stock (forged pistons are the only thing we have really worked out different) The guy helpin me says he has somethin up his sleave for the motor and Im really lookin forward to gettin it goin!
Where Im goin with this...if we DO decide to go turbo finally, how much boost do you think we would be safe to run? I will have forged pistons and an intercooler (air/air). The motor will be rebuilt fully and ready to rock. Is there anyway I could run a boost controller and turn the boost down for daily driving and then back up if I feel the urge, or will it need to be tuned for either or? Its all a matter of money now, once I get it, its time to boost!
Matt

 

[Does10s]

Matt,
The amount of boost that the motor can take is mainly dependant upon the type and the amount of fuel you've got. A proper fuel system that will increase pressure as boost increases is paramount. If you run 100% race fuel then 20+lbs. of boost will be no problem.
But on pump gas then maybe 10-12lbs. might be a safe tune.
Also watch the timing. Keep total timing down to around 22-25 degrees and you'll be save.
Boost can be controlled from the cockpit by two means. An electronic boost controller (read: expensive!) or a manual one that uses a ball/spring type valve or a bleed-off type deal. Google for "boost controller" and something will show up.
Later,
Will

 

[66Sprint6]

I have looked into controllers and year, the electric ones are out of the question. I was thinkin one of the little manual ones. Would I have to re-tune the car to turn the boost up and down or would it be fine so long as I am running a boost referenced fuel pump and a boost timing master?
Matt

 

[hasa68mustang]

ok correct me if I'm wrong anyone but I think you can use a wastegate, which reroutes the air (over the set amount) to the exhast so it doesnt go through the engine, ok well I copied a part from howstuffworks.com "Most automotive turbochargers have a wastegate, which allows the use of a smaller turbocharger to reduce lag while preventing it from spinning too quickly at high engine speeds. The wastegate is a valve that allows the exhaust to bypass the turbine blades. The wastegate senses the boost pressure. If the pressure gets too high, it could be an indicator that the turbine is spinning too quickly, so the wastegate bypasses some of the exhaust around the turbine blades, allowing the blades to slow down."

How did I miss this thread??? Must have been on Thankgiving weekend!

It's true that Kelly's Falcon is mainly a drag car. However we've driven it all over the place and it does very well on the street. Doesn't overheat, idles like a stocker etc. The only difference is that we have to manually shift the automatic, and we can beat damn near anything that pulls up next to us!!!
We've run her car up to 16lbs. of boost. (by accident ) and I've never felt that the car was going to grenade. It's all in the tune up! If you run the thing lean or if it goes lean by itself due to some failure of a part then yes, you'll probably hole a piston. That can be done at 6lbs. of boost.

I bet Kelly's stock US 250 motor will easily hold up to 20+ lbs. of boost. As the learning curve progresses, her crew chief (me) will slowly start to crank up the wastegate!
Will

there is a post of does10s notice the last sentance where he says we will start to crank the wastegate up, I again am pretty surre, but not 100% good luck, Tommy

 

[XFlow_Fairlane]

the controller is there to fool the wastegate. if you can find a wastegate with a threaded arm on it (does10s is running a extrenal gate) if you can't find a cheap threaded one a "grainger" valve will work fine as will a bleeder. I would do the mods needed to the carb and pump and start at a low boost level with a A/F gauge and turn up boost if it is a littel rich. as long as your timing is good you should be very safe. with forged pistons you will have a pretty bullet proof motor.

how is the rest of the car though? rear end? brakes? tranny?

remember if you start huffing 20psi on that motor it will prob be getting up ther ein torque so you will want a good rear and tranny in there.

 

[66Sprint6]

The rear is stock, the tranny is a World Class T5 (no worries there). We are looking to hold onto the stock rear for a bit then swap it out for a 9inch later. I know what a wastegate does and how, but my main concern is whether or not I need to worry about tuning when I turn the boost up for a run, then back down to drive her home.
Matt

 

[Does10s]

9"? Don't waste your time. Kelly's Falcon has one and we're going to pull it to save weight. An nice 8" would work fine.
Yes you can easily turn up the boost at the track then back down for the ride home. If you're going to run a BTM then you might want to pull another degree or two of timing out. AND/OR add a few gallons of race gas to up the octane a bit. This would be a good safety measure during initial start-up/test run.
Always remember that you're running a blow-thru carb. So if the air increases thru the venturi, it'll pull more fuel out too. So long as the jet is large enough! And the pump can keep up!
So far on Kelly's car I've been playing a little with boost levels and jetting. I haven't touched the timing since we initially set it up.
Later,
Will

 

[66Sprint6]

Thanks alot Will, thats what I was lookin to find out. I figured as much, but I didnt want to mess somethin up because of my ignorance!!! I cant wait to get this going tho! I hope we get the time and $$$ to put the turbo on while its settin there.
Matt