Ported elbow with stock DP?

[DougsfastZ]

Any advantage to porting the stock elbow utilizing a stock downpipe? I'm on a budget If so, where do I port? Also should I port the puck opening larger and get a new puck (if they are available)? The car does boost spike so I would like to make the puck opening larger. The car is stock turbo, IC and mods below.

Thanks,

Doug D

 

[UNGN]

Open the Outlet of the elbow to the outside diameter of the Donut gasket (about 2.6").

Then grind a smooth "short side radius" going into the hole. You may need to take some material off the gasket sheet metal to make a smooth transition into the hole. At this point, a 2.5" diameter ball should pass through the elbow (with the gasket removed).

Smooth and lower the "wall" between the wastegate outlet and the elbow outlet hole and make a smooth raduis into the outlet.

Make sure no part of the inlet of the elbow covers the outlet of the turbo (more likely with a larger turbo). If it does, blend away the areas of interference.

Smooth and polish the inside of the elbow.

Finally, use a large, smooth file or a 6" sharpening stone to lap the turbo side of the elbow flat, to ensure no leaks.

As for a "boost spike", opening the wastegate port usually will not remedy this. This is usually a function of the chip going wide open on the boost solenoid. The largest wastegate hole in the world won't help if the solenoid isn't telling the actuator to open.

Opening the wastegate hole is for boost creep, which happens in the upper gears with boost creeping up from it's set limit. The first step to eliminating boost creep is to ensure there is a smooth transition into the wastegate hole, inside the turbo's turbine housing. Usually this is a square sided hole. By porting a smooth transition from the internal passage to the wastegate hole, the hole will flow much more, without requiring a larger puck. The more it flows, the more boost control you'll have (unless the solenoid is wide open, of course).

 

[DougsfastZ]

Thanks UNGN, do you think it's worth it on a stock DP? Do I use a dremel to get all of this done? About boost spike, I don't use the stock solenoid, rather an RJC racing controller, still get a 2 psi spike, any ideas?

Doug D

 

[VadersV6]

I'm planning on buying a used elbow, and CNC porting it (I'm a CNC programmer/machinist)... Not to mention years and years of engine building and porting experience. Anyway, I'd be interested in knowing what kind of gains I'll see with this at 20psi and a stock DP/exhaust.

 

[UNGN]

The stock elbow is slightly more of a restriction than the stock downpipe. Switching to a mandrel bent 2.5" stock replacement might net some gains, though they would be hard to measure.

I did a back to back comparison between the stock Elbow/2.5" downpipe and a 3" THDP. I did 6 runs with each and tried to make it as scientific as I could.

The THDP was .05 seconds and 1.5 mph faster than the stock elbow, with most of the THDP gains appearing in the upper RPM range.

The Stock elbow ET's averaged 11.84 while the THDP ET's averaged 11.79

MPH went from about 114 Avg. to about 115.5 Avg so the THDP makes more peak HP than a stock elbow, but into the 11's a stock elbow will slow you down no more than .1 second and 2 mph vs. a THDP.

And before the "I picked up .4 seconds and 4 mph with a THDP" people chime in, I did, too when I first switched because my car had other problems and I wasn't using boost sensing to see if my boost level was identical. Also, these 11.70-11.80 times were done with a stock motor and a TA-49/bluetops/drag radials. If you use a larger turbo you may pick up more with a THDP, but if you go from 12.8 to 12.4 switching to a THDP, you aint anywhere near the limits of a stock elbow, yet, so don't blame the elbow.

 

[Quick6'n'-K.C.]

pic or 2

 

[Quick6'n'-K.C.]

Lots of porting to do, usually get at least 1 tenth and 1 mph

BW

 

[DougsfastZ]

Thanks UN, maybe I'll hold off on a "real" dp longer then I thought

Quick, those pics help ALOT. Do you have any more? Did you use a dremel, drill or air tools? What kind of kit do I need to buy that I can port and polish?

Thanks guys,

Doug D

 

[salvageV6]

In the folder from the link below there are some pictures of the stocker and a TurboMike ported stock housing.

Note the large puck install he did also.

He no longer does this work however, but did do it for several years.

IF you can dig one of these up used and clean it up a bit you might save yourself some work and the trouble adding the larger puck.

http://members12.clubphoto.com/allan631980/1733377/owner-0a12.phtml

Double click on the pictures for the highest resolution.

Good luck.

 

[Quick6'n'-K.C.]

Thanks UN, maybe I'll hold off on a "real" dp longer then I thought

Quick, those pics help ALOT. Do you have any more? Did you use a dremel, drill or air tools? What kind of kit do I need to buy that I can port and polish?

Thanks guys,

Doug D

I bought my High speed bits from matco about 10 years ago, im pretty sure you could look any carbide bit online. I know i spent 60.00 on just one bit for cutting aluminum, but i can do a complete lower intake in less than a hour now :biggrin:
The regular carbide bits cost between 20-30?
I use the carbide bit to get the majority off, then smooth it with a less aggressive carbide bit, then take a 80 grit flapper wheel to smooth it out.
I use just a plain ole air die grinder, heck even the cheapest crapola tool from walmart works just as fine as my bluepoint :biggrin:

Send me a email for more pics
BW

 

[UNGN]

I use a dremel to port stuff, but use double cut carbide burrs (double cut splinters are less needle like than single cut). I can do a set of heads with one burr and 1/2 to 1/3 a dremel tool (I send them back to dremel for a $35 replacement).

With a good burr, cast iron will cut like butter.