Build Thread Want To Blow 5 Years And $50k On A Foxbody? Step By Step Instructions Inside!

It's been a hot minute since I took thermodynamics, so no. I've been known to be wrong on occasion...
but I think you use PV=nRT and p1v1=p2v2 in some sort of combination to figure out why it isn't doing what it needs to.


I know what you're thinking. It's a bit counter intuitive. Think back though to just about every diagram of a pressurized hydraulic/pneumatic system. You have a pump, an accumulator, a cooler, a pressure relief valve (the BOV) that returns pressurized excess back to the accumulator (ambient air in our case) and actuates a cylinder or turns a motor (the engine). Recall that relief valves return system volume to the accumulator and NOT system pressure.

So in the scenario above, where will the pressure drop be? So long as volume is supplied, there won't be a pressure drop. Air heats as it squeezes and accelerates, as soon as it expands again it slows, expands, cools rapidly and takes up less space per cubic measure than it did when it was hot.

If anyone recalls, the OLD discussions about the fuel rails were about why we were able to make so much more HP with 42 lb injectors and stock rails versus smaller injectors and FMUs (pumps were removed from the equation because both setups run the same pumps).

Anyway... Reminds me a great deal of sitting in hydraulic, and electro-environmental classes.
 
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That's the plan Mike. I can leave my Holley MAP sensor as is and just tap my plx gauge into the compressor lines for the boost controller. Both will give me max values, so I can easily compare the numbers. All this theory talk is fun though.
 
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Hmm, guess this could cause a boost leak, huh?

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Id be willing to bet a ham sandwich that the pressure on the turbo side is higher than 15 psi. You essentially have a nozzle and a diffuser back to back, where a nozzle converts pressure into velocity and the diffuser effectively kills the velocity... Since the air lacks pressure and velocity, it is unable to pressurize V2 to the pressure that it once was.

That's the plan Mike. I can leave my Holley MAP sensor as is and just tap my plx gauge into the compressor lines for the boost controller. Both will give me max values, so I can easily compare the numbers. All this theory talk is fun though.


It would be cool to see. I still think that the engine would be a larger restriction than the intercooler. If that's true, then pressure should be equal on both sides. :chin
 
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The CX racing intercooler still has no business on that car.

You're right about that. If my boosting issues are solved for now, the intercooler will stay for a little while. I'd rather spend that money on a twin disc clutch right now.

It would be cool to see. I still think that the engine would be a larger restriction than the intercooler. If that's true, then pressure should be equal on both sides. :chin

There will still be a measurable pressure drop, but it shouldn't be more than 1-1.5 psi.
 
So then,........another trip to the dyno, or are we gonna save that till after the new rings are ran in?

I gotta tell ya, my concerns for not doing that w/ my initial start up is high on the worryometer for me. It's not like I don't have enough to worry about w/ the mechanicals already.

Thanks for adding one more possible calamity as a reason to not try and start that thing.
 
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Yes. Won't be back again until the spring. The car is still operates fine as it is. Just no high RPM deceleration.

Washing down my cylinder walls was because I used the tune from my old setup. At the time I was fighting a cold engine idle issue and I had a ton of fuel added at idle in the coolant tables. I completely forgot about those tables, so adding a lot of fuel with the 95lb injectors sealed the fate of the rings.

I think as long as you make sure your tune is generally where it should be, you'll be okay. Watch that wideband like a hawk too. I learned my lesson the hard way, that's for sure.
 
I'm hoping it will be fine. I had the car out this weekend and saw 8-9lbs of boost off the 10lb gate spring, so it's definitely where it should be. Once I get some things worked out with the tune, I'll take it out again to compare pre and post-intercooler pressure.

My damn hvac is only coming through the defrost, so I gotta check those vacuum lines.

I also purchased a leak down tester. I want to eliminate valve seals as a potential problem and be sure the rings are my only issue before I start tearing things apart over the winter.
 
The tune is still a little rough. It won't idle until it gets to operating temperature. Once it's there, the idle is rock solid. There is also a random stalling issue when letting off the gas and coasting to a stop. It doesn't do it often, but it's annoying to not know if or when it may happen. Kris is going to help me over phone/email to get that stuff ironed out. Pulls like a raped ape when my foot gets heavy though. And that turbo and BOV sound makes my jeans tight every time.

Half my dash isn't bolted down so there are some rattles right now. There is also no floor in the hatch yet, so the fuel pump is quite audible. It definitely rides well with the IRS though, considering how low the car sits and the springs that are in it along with the low profile tires. The ride is firm, but not crazy harsh. One all the interior is bolted down, it will be even nicer. The downpipe is also hitting the lower k-member mount near the firewall. I'll clearance that when the engine is out. The spec clutch needs to go though. I'm no longer a fan of it. A smoother twin disc will make it much more enjoyable to drive around town.

It is strange driving with the 3.27 gears. 2000 RPM at 70mph in 5th. I can't even hear the exhaust at that speed, which I don't mind. Never enjoyed the flowmaster drone when cruising on the highway.

There is still plenty to iron out, but it's very close to where I want it to be.
 
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