Oh, porting of the turbine housing, the T3 and T4 housings don't have much area for improvement when it comes to porting like the stock stuff does.

 

yeah it's too bad the GT housing wasn't more compact. Either that or I need to take off my A/C

 

Did you miss the part about the custom machined GT housing It's compact enough now.

 

pictars please!

I was looking at the head flange, turbine inlet flange, and the precision 6262 T3 .82 AR Housing tonight...

The SLS CNC'd head flange has recessed ports in the head for 1.5" sch10 tubes to sit in (not really necessary) and due to this the tube comes very close to the bolt holes (on top) and once you lay a fatty bead on it... your fasteners will be clamping on the weld and not a flat flange surface!!!! So I'm looking for a new head flange... perferrably one that is 2D and is not contoured like the SLS unit.

The CNC'd turbine T3 inlet flange appears to be drawn off of a smaller T3 opening than the std t3 housings. I'll either have to hand port this out to the right size... or just buy a 1/2" thick RIGHT SIZE T3 flange.

Upon looking at my T3 turbine housing from Precision (looks like a 4 Bolt std t3 housing that was lathed down to make a 2.5" v-band outlet) Looks uber small and will require a 2.5"->3" transition...which takes up precious lateral space while serving NO good purpose! I was considering making a fixture to bolt my housing to (6 bolts that bolt from the center section). Bolt the housing to a big block of 7075 that I have sitting around, and mill the discharge down as far as possible. By my eye-crometer I think I'll be able to get up to 3/8" more lateral room by machining the housing in further. I would then weld a 3" v-band flange onto the turbine discharge and then port/blend the turbine housing to the discharge.

By my estimates I'll save at least 1/2" by not using a 2.5" to 3" transition and then I'll save another 3/8" by machining the housing. This gives me a whopping 7/8"!!!!! to fit my fatty large CLR 3" tube through.

What's your take on my idea Dave? I'll have to hit up some people for advice on TIG welding to a cast iron housing. (Preheat + Nickle Rod using a Mild Steel v-band flange)

 

We have a 3/8" thick SS header flange we use with the schedule 10 tubing. I buy my T3 collector from Shearer for any custom headers we do, because his are just to nice to mess with trying to make on our own.

The 6262 housing........sorry you are screwed using ours. I thought you had a GT35r, that housing we have the Garrett T3 GT housing machined specially for our FF kits and the 3" V'band end up nearly flush with the side of the turbine housing. VERY compact. We had to machine them so a full 3" 02 housing in Vband would fit our FF kit.

 

Nice work dave. If I ever go to a 35r variant I'll let you know. Can you PM me a price on the head flange?

I make my collectors at a lower angle and subsequently longer than most people do for the Evo... so I'll just end up making mine.

 

would exhuast wrap really help the flow and gain any hp or tq? A lot of people wrap the header and dp, would wraping the whole exhuast be better than just the dp?

 

The wrap helps to hold heat in the exhaust. Hot air travels faster than cold, thus, in theory, the wrap should improve exhaust flow.

In addition, the wrap will greatly reduce under hood temps.

I have mine wrapped from the O2 housing out to the resonator. After the resonator is not wrapped.

I also helped to quied the tone in the car.

 

It's pretty interesting to look at pressure drops relative to air temperature.

As velocity goes up, frictional losses usually do too...

Good heat management has a lot of benefits over changing air velocities though.

 

Heat has a direct relationship with pressure within a given volume. Pressure can be increased which will cause an increase in heat and vice versa.

If air is heated and released it will move at a faster rate than cold air.

In the case of the exhaust, controlling the heat is essential to keeping volumetric flow maximized. If the exhaust is allowed to cool too quickly some of the scavenging effect could be lost.

Frictional forces of smooth walled pipe and exhaust gasses are, in my opinion, very minimal when used to determine velocity. Bends will affect the velocity more than the frictional forces of the pipe.

AAAHHHHH Fluid Dynamics....I hated that class.

 

To maximize turbine efficiency, you want the exhaust pre-turbine as hot as possible (highest pressure) and the exhaust post-turbine as low a pressure as possible (low temperature).

So, ideally you do not want to wrap anything post-turbine, such as the O2 housing or downpipe. Most ppl do it for a couple of other reasons, though, such as quieting down the exhaust note a touch and/or to control heat to nearby components.

 

But if there is too quickly of a pressure drop you create turbulence in the flow which hinders flow considerably. Thus my suggestion earlier about an increasing diameter pipe (like a cone) from the turbo out. Then you can decerease pressure and minimize turbulence while still keeping the flow as fast as possible.

Wraping the DP isn't a bad thing by any means. They run so close to the oil pan that anything that can be done to reduce radiant heat getting to the oil is good.

 

An exhaust isn't a closed system. Increasing the heat does not increase the pressure, since it is an open system the air at higher temperature just expands to fill a larger volume.

If air is heated and released at the same pressure as cold air, frictional losses will dictate mass flow rate. Because the air is more "excited" at higher temps, you'll find that frictional losses increase as temperatures increase.

Frictional forces aren't about calculating velocity. That's pretty much left to mass flow rate and fluid density in a system like an exhaust, mass balance. Frictional loses will create pressure drops though and, at least from theory, produce rather large losses in exhaust systems.

Agreed and as stated above, losses in bends are huge and keeping heat out of the oil is the #1 reason I have a wrapped downpipe.

 

Thanks for the lesson.....It has been years since I had those classes. It is amazing what you lose if you don't use.

I too wrapped my DP and out to the resonator for keeping heat out of the oil and out of the cab. I had to remove my cat heat shield because it rattled like crazy.

 

I don't like wrapping anything after the turbine housing either. We use a shield on the oil pan that we started using originally when we built the BR330 and BR350 Edition EVO's. It's a simple self adhesive heat shield that we stick on the oil pans over the downpipe. I have one on my RS. I have used ceramic coating on the downpipe.