http://www.torquecentral.com/showthr...ighlight=turbo

Heres the thread i meant to post earlier hehe. The setup is looking great wingsfan. That thing is gonna make some power.

 

Looks like you have the makings of a turbo setup Wingsfan. Can't wait to see the finished product. You should just run the 5.3 cast manifold on the drivers side. It at least won't crack.

Your mild steel will be prone to constant cracking even with hi temp coating. I'd do it right and do 321 s/s.

Good luck with the project.

BTW- where did you get the collectors?

-GNX7

 

Doesn't fit. And I sold them to 1point3liter. He's goign to try to modify them to suit his needs.

Well, when you start crapping $$$ you let me know and send some my way.

Thanks.

Headers by Ed

 

Haven't updated this thread in awhile, and since I'm an attention *****, and many of you don't frequent Torquecentral...well here's a few pics. I've been busy.

 

Couple more

 

Some specs.

The turbo is a Precision T76-GTS. Rated to 1100 bhp. 3" to 4" downpipe. 1.75" primaries 3" collectors reduced to 2.5" that Y together to a 3" feed pipe (open T4). I went with the Turbosmart progate 48mm wastegate (stuck in customs), and v-band clamps on everything. Once the WG gets here I'll wrap it up and send them off to Jet Hot for coating.

There's light at the end of the tunnel.

 

Why does it have a expanding dump pipe?

Wouldnt you want it to taper to make sure its going to keep up velocity? If youre going this far might as well nitpick everything

Oh, and throw that monster in a wind tunnel and route the opening for the exhaust into a low-pressure area of the car when at speed for a little extra oomph.

 

Because velocity doesn't mean **** after the turbo. It's all about eliminating back pressure. You want the wheels on the turbo spinning as freely as possible. Bigger DP means less restriction in the flow, and faster spool.

I don't think oomph is going to be my biggest problem.

 

THERE IS NO SUCH THING |AS TOO MUCH OOMPH!

And I know its about eliminating your backpressure. I have heard that for really long exhaust systems or for some that are too big for the application (which I doubt in this case, but in principle...) the speed of the exhaust gas can slow down and build up a little bit of backpressure in trying to shove out the stagnated air. If its tapering, as it cools going down the pipe it will be less likely to slow down.

But then again the dump pipe looks pretty short so its not really a signifigant effect in this case

 

That may be true for an NA applicaiton, but those rules simply don't apply for a turbo situation. Flow is essentially irrelevant since there's a huge restiction (the turbo) in the exhaust path.

It's 4". It's not too big for the application. Go spend some time on a Supra board, or in the FI section at LS1 tech and you'll see what I mean.

There's 5.7L of engine (soon to be 6.3L) pushing exhaust through a 3" opening at the turbo at around 1600º. I could go upwards of 5" in diameter and it still wouldn't be too big for this app.

Again, relevant for NA, not for FI. The exhaust temps I'll see with the restriction the turbocharger provides will massively exceed what I would see in an NA application. There won't be any problems with cooling.

It's not short. It's going to be 4" all the way to the back.

 

jesus man....you are going to have one hell of a monster once you get it all finished.


yowza.

 

I must not have looked at the pics right, because it looked like one of those wide stubby dump pipes thats barely more than 2 feet long that Ive seen on some of the crazier turbo cars.

But, if its 4" all the way to the back, well then I stand corrected.

BTW, where the hell do you go to find out proper exhaust diameter size for a given hp? Or is it still more of a black art than anything else?

 

Well, the rest of the exhaust path isn't finished yet, so that might be where you're confused. I plan on running a conventional catback so that I can run it on the street. I'm even going to try and pass smog with it.

I'm sure there's a way that you can determine it, but I'm not aware of the exact calculations. Most of what I've setup has just been through empirical observations. For instance, I know that people running the turbo I am have had problems with backpressure casuing detonation when they run a combination of larger displacement (408 CID), and a small downpipe (3").

For turbo purposes you pretty much want to run the biggest exhaust you can fit. A 4" exhaust path is going to provide me with some wiggle room in regards to back pressure.

 

Yup, that's the idea. The camshaft that I picked out should have a very gentle idle to it as well. People that don't know any better won't suspect that it has anything other than a large exhaust. I'm hoping to sneak up on a few people.

And of course, I plan to catch a lot of flak by taking it to a TexasRxs meet. Too bad you're not in town anymore.

 

Not necessarily the case with ALL turbo vehicles but with the flow characteristics of high HP/high flow engines like V8s, you are correct. Ideal would be no exhaust at all on a turbo application but if one must be run, it is important to chose a correct diameter as to not create turbulence. Again, not something most of the people here need to worry about but its good to understand that the largest possible diameter exhaust isnt always best for a turbo application.

-Tim

 

Thanks Andrew. You have made me totaly make up my mind about not going turbo. I'm just going to build a mean Stroker setup.

And the TexasRX's guys gave me a weird look when I told them about my plans. But they saw where I was coming from. They'll talk **** until you beat their asses.

 

Which is pretty much the same thing as putting in the biggest piece of pipe you can fit. I can't think of a situation where you would want to restrict post turbo flow.

 

i told you it would be damn tight, and you'd lose the things that make the car comfortable. It's one of those things I can say until I'm blue in the face and no one understands...show them a picture, and it's a "lightbulb" type moment. :rluagh:

I have yet to run into anyone who's been a dick in person. Plenty of keyboard warriors though.

One of these days I'll make it out there for a meeting...even if the only erason is that we're running low on Rudy's "Sause".