I decided to test-fit the manifold and downpipe this evening, so I could mark the locations where I'm going to install the O2 sensor and EGT fittings.
It's definitely a tight fit, but that's what you get with such a fat pipe. Shame Greddy didn't move the turbo forward an inch or two on the manifold. The only area where I think I'm going to have a problem is where the little bracket normally goes (on the stock downpipe) to secure it to the bellhousing. It's a real tight fit, and I think it may have a tendancy to rattle against hit the bellhousing. This is exactly where the slip-couping is which joins the two pipe sections, so I think I'm going to try to kill two birds with one stone and fabricate a bracket similar to the factory piece which will mount to the exhaust clamp which I plan to use in this spot.
All in all, I'm very happy with the system thus far. Now if only my fuel injectors would get here so I can go forward with the project.
Make sure if you make a bracket it doesnt cause the downpipe any stress. I had one welded in (exhaust guy suggest it, I wanted to redo the DP) to keep the DP from vibrate against the control arm at some rpms. I'm fairly certain it's why my manifold has cracked so many times.
I guess now that everything is in and running, a few "after" shots are merited. After welding in the fittings I had the pipe ceramic coated, and not only does it look good, but it really cuts down on the heat. Very important since it sits a lot closer to the speedo cable, heater hose and brake lines than the stock Greddy piece did.
As I feared, I did run into trouble with the downpipe hitting the bellhousing when I bolted the turbo down into place. In those first pictures I posted the turbo was just sitting loosely on the manifold. In the end I decided to open up the holes in the DP flange a bit with a die grinder so that I could rotate the whole assembly a few degrees relative to the turbine outlet in order to center the downpipe between the bellhousing and the subframe.
Braineack, I took your advice and bought a sleeve clamp to hold the two sections together- this way there's a little bit of flex between them, should help take some stress off the manifold. It worked nicely. I also made a small bracket out of 18ga sheet steel to attach the lower section of the downpipe to one of the bellhousing bolts, similar to the factory bracket. I used a U clamp to hold this in place on the pipe.
Pictures are attached showing the final placement of the EGT probe and the two O2 sensors. The narrowband 4-wire is sort of below the turbo facing forward, the wideband is down below in the lower section, pointing straight up, and the EGT probe is on the side pointed at the head. My reason for putting the WBO2 sensor here is that I was thus able to run the cable for it up through the shifter boot, so I didn't have to make another firewall penetration.
All in all a very nice piece of hardware. For those of you who want to buy one, TurboTony is the second poster in this thread. PM him.
I didn't clamp mine and it's doing fine, but I do need to replace my exhaust hangers, the system I had fabbed up is heavy enough to tax the stockers to the point where my exhaust is rubbing against other things.
very nice ! does the tony dp come with the bungs for o2 ? and maybe the egt ? or did you weld them yourself ?
He will build it any way you want.
The "standard" Tony Pipe has one bung for the O2 sensor installed in more or less the same place as the stock Greddy location. Since I was afraid this would interfere with my heatshield and also I knew I was going to be adding some other fittings as well, I asked him to build the pipe with no fittings.
I then took the pipes (upper & lower) to a local independent exhaust shop and had two O2 fittings and one EGT fitting installed. I pre-drilled the pipe and supplied the EGT and one of the two O2 bungs, and they charged me $20 to weld them in, including the cost of the second O2 bung which they supplied. This was somewhat on the cheap side, probably because it took three days to finish, and it was just a handshake job- no paperwork. The owner of the shop wanted to experiment with his new TIG welder at the time, which is why it took so long. There's a lesson here- avoid chain exhaust shops like Midas. Independent shops are much nicer to deal with on stuff like this.
After that, I stripped and cleaned the upper pipe and had it ceramic coated for $75. The lower I just re-sprayed with heat resistant header paint.
I've got my narrowband (4-wire) sensor mounted inside the curve of the DP with the wires facing forward, the EGT probe right at the turbine outlet on the inboard side of the pipe, and the WBO2 down about 12" before the cat, pointing straight up. If you look around, I know there are pictures of the setup somewhere around here. Just search for posts from my name containing the word “Tony”.
Placing the EGT probe before the turbo will give more accurate readings. I chose to put it post-turbo however as I've heard the occasional horror story of the probe tip breaking off and being ingested through the turbine. Never happened to anyone I know, but it seems like a valid possibility. By placing it post-turbo you will read lower temps, but it's really relative readings that we're concerned with, since EGT probes aren't terribly accurate to begin with.
I'm an idiot. I just realized that the pictures are in this very thread.
I sent an email to Tony yesterday asking if he could construct a 3" DP for me. It was a project he was planning to tackle after Thanksgiving, so good timing for me. Anyways, I started to give a bigger DP and commensurate-sized exhaust serious consideration after standin behind my car at the dyno day and feeling how damn much air is being pushed thru the exhaust. I described it like being in a wind tunnel and I was 20 feet or so from the tailpipe! A larger diameter DP (and test pipe) should help the turbo spool a bit quicker.
A note on my EGT install, I installed the probe into the manifold thru a threaded hole in the bottom. Since I am using the stock fuel pump, 440 injectors, Vishnu rail and an RX7 AFM, I use the EGT to tune the A/F mix. I have the old-style 02 sensor and it can't be completely trusted.
440's on the stock ECU? You're even crazier than me!
Seriously though. I can't imagine how you'd get a 3" downpipe to fit, given the placement of the turbo on the Greddy manifold. When I installed my 2.5" pipe, it was truly amazing just how big the thing was, and how little clearance there was around it in certain places. My biggest worrk would be where the pipe passes between the bellhousing and the subframe. That is a *very* tight spot. This ain't no diesel truck, after all.
Does anybody here who is better versed in fluid dynamics than I have an opinion as to the merits of increasing the diameter of a pipe subsequent to a restriction? When I mean is that the outlet of the turbine housing is quite small, and I wonder how much gain there is to be had in increasing the diameter of the pipe beyond a certain point, given that fixed restriction.