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

[RacEoHolic330]

Well good for you. Despite the persistent low boost bug, it looks like one of us had a better day than the other one did.

And....

Isn't an "exhaust cutout" that hole they put in your throat as a result of too much menthol injection?

Let people say what they will about lengthy worded updates, and replies. I prefer to read the story that goes with the pics, as opposed to "here are some pics, enjoy."

That does say something about the fact that I caught your word usage issues.

Hah! Frigging autocorrect. I didn't even notice that typo. I wonder if the car could benefit from a little nicotine though. Hmm...

 

[RacEoHolic330]

Awesome, you'll get the boost scenario worked out pretty easy, Hope the cruise was a blast and lasted a long time!

I'll see if I can get the go pro mounted somewhere for the ride tonight.

 

[squeak93]

VERY NICE! Glad to see hard work pay off and someone being able to enjoy a nice example of a Fox.

Sit back and enjoy the car now!

 

[FoxMustangLvr]

Why are the HP & TQ numbers different from the first time at the same amount of boost? Is it the Mustang Dyno? The previous tuning session was done at All Out with Kris, right? And now you went to a different shop? The first tuning session you got 680HP/657ft-lb @ 15PSI on washed cylinders and now your getting 600hp/600tq @15psi on a healthy engine. Why is that you think? I would assume you had mufflers on your car for both dyno sessions.

 

[RacEoHolic330]

The difference is partially because of the dyno. Mustang dynos are known as heartbreak dynos because they read lower than other dynos. I don't know how much lower they read than the Dynocom dyno at All Out.

The other difference is that that 600hp was only at 5300 rpm, compared to 5900 previously. For whatever reason, it doesn't want to make more power above that right now. The back to back dyno runs in 91 degree weather could also be a factor. It was in the 60s the last time the car was out. The air filter was also connected this time, whatever that's worth. It is interesting that the torque numbers went up a decent amount though. Frank said the car should be making a lot more torque and it's not because of the backpressure issue.

Too many variables from switching dynos to know for sure. I use it as a tool, so as long as it's the same dyno next time, I'll know that things are moving in the right direction after making changes.

 

[GroverDill]

I am surprised of the back pressure problem. I have a few more cubes on a similar turb0 and it makes boost to the moon.

 

[FoxMustangLvr]

Where are my manners, first off congrats to you on a good running car and a successful dyno tune.

Now back to the little things. What size headers and exhaust do you have? Do you have cats? Don't other people make good numbers with a full exhaust and a turbo like @GroverDill ? I just don't see cutouts being enjoyable and your car is too classy to sound like a dragster. I'm not the smartest about big HP turbo cars so I'm trying to wrap my head around the logic.

 

[RacEoHolic330]

I agree with you guys that it may not be solely a backpressure issue. First thing will be checking the wastegate diaphragm. I might have messed it up when I was replacing the spring or something.

The headers are 1-3/4" to a 3.5" downpipe, to a 3" dual Y pipe and then into a 2.5" Magnaflow catback.

@GroverDill, what wastegate spring size are you running?

 

[GroverDill]

tial 44 with a 15 psi spring. I even have less downpipe.

1 3/4" headers, 3" down to a 3" Y into dual 3" non chambered mufflers ( forget the brand, a maganflow knock off I think )

 

[RacEoHolic330]

Yea. That's interesting and definitely contests the backpressure issue theory.

I was only seeing about 6lbs on the 10lb spring.

My only other thought besides wastegate issues could be my cx racing intercooler. We talk about this being a potential issue before.

 

[GroverDill]

The CX racing intercooler still has no business on that car.

 

[RacEoHolic330]

Blah blah blahhhhh.

I'm going to check the gate first for potential issues and also up the spring size. The fact that I'm only seeing 6 psi on the 10 psi spring is a little concerning. I'll measure the pressure directly off the compressor housing to determine if the intercooler is causing issues for me.

What I really need to do also is measure backpressure at the turbo as well. That's easier said than done though.

 

[90lxcoupe]

I'll agree that the exhaust is hurting a bunch, a friend picked up .2 in the eighth mile going from a full 4" pipe out the side right by the rear tire, to a 4" fender exit.
The cutout is the perfect solution for your car, i also would be surprised if the intercooler was the problem, just because it is cheap doesnt make it junk, people have made a ton more power with them.

 

[RacEoHolic330]

Good points. I can easily test the intercooler drop by swapping my plx gauge to a T off the boost controller while leaving the Holley MAP sensor on the manifold line. The two read within a half psi of each other, so it will be a relatively accurate test.

The Tial gate came with the turbo kit when I bought it used. My luck with used parts has been less than stellar, so it would be my luck that something is wrong with the gate.

For the spring, I've learned that having too small of a spring can prevent the turbo from spooling adequately to higher boost levels depending on backpressure. I'll up it to a 15 psi spring and see how that helps also.

 

[90lxcoupe]

Im sure you will figure it out, you also have the right attitude about dyno numbers, like you said, it is a tool, the numbers really dont mean too much at the end of the day, if the combination is happy it will show on the dyno and it is a great tool to test what works and what does not.

 

[Noobz347]

Screw it. Just drive the damned thing until something pops and you have to replace it. hehe

So long as you're making in the neighborhood of 400 HP before 2800 rpm? Win! ...and a ton of fun on the street. lol

 

[CarMichael Angelo]

Good points. I can easily test the intercooler drop by swapping my plx gauge to a T off the boost controller while leaving the Holley MAP sensor on the manifold line. The two read within a half psi of each other, so it will be a relatively accurate test.

The Tial gate came with the turbo kit when I bought it used. My luck with used parts has been less than stellar, so it would be my luck that something is wrong with the gate.

For the spring, I've learned that having too small of a spring can prevent the turbo from spooling adequately to higher boost levels depending on backpressure. I'll up it to a 15 psi spring and see how that helps also.

Huh,...two uses of the word "stellar" w/i a couple of days.......go figure.

 

[TOOLOW91]

Awesome pal I am glad to see this is all finally paying off


Sent from my iPhone using my fingers while my auto correct makes me seem illiterate

 

[RacEoHolic330]

Thanks man. I'm excited to finally be able to enjoy it.

So, I opened up the wastegate today and I believe I found the problem.

I knew I had a yellow spring, which according to Tial is an 8.7psi spring. The issue is that spring pictured is not a large spring, it's a small one. The small yellow is rated for 2.9psi. When I originally checked the spring with my untrained eye, I didn't even consider the fact that there are large and small springs the same color. Duh! That completely explains not being able to hit the higher boost numbers.

 

[stangboy]

Congrats on finally being able to enjoy your car!! Also on figuring out the boost problem.