Ok - the results are in, and it looks like my car needs to go back under the knife. The Pipers put down 281 HP and 251 torque vs the 274 hp and 253 torque that the HKS cams gave. The HP and torque curves were almost identical.

What did come out in testing was that neither of these set-ups yeilded anywhere near the 310 whp that I had earlier. My best guess is that perhaps the bottom end slipped a tooth the last time the head was out. That would result in a 14 dgree offset of the mechanical timing, which might reduce performance like this - guess I'll be opening up the timing cover to find out.

 

Hmm - the problem wasn't the bottom end timing. There were 3 significant changes when I put the head back in and lost power. The first was that the head had been decked .005" The second was that I switched from Pipers to HKS cams - further testing seems to have eliminated the cams. The third change was reflashing my XEDE from V2 to V3 firmware and updating the maps.

The XEDE has been a bit flakey since the reflash, but I think it's problem with my specific unit vs the v3 upgrade in general. One example of the new flakeyness is that my second map bank has gone dead in the XEDE. I'll be shiping the unit off to Vishnu next week for diagnosis and repair under warranty. If the XEDE (or it's related maps) aren't the problem then I'll need to look back into the head; I hope the problem doesn't lie there.

 

OK - did more testing and found a boost leak along the main intake path. Looks like one of the clamps gave up after being loosened and tightened too many times. That should stabilize the AFRs again. I also removed my modified boost pill to eliminate any possible problems being caused there.

I have re-tested my XEDE, and I borrowed a spare to test with as well. No problems in that area; the odd behavior I had earlier was completely resolved when I reflashed my XEDE with the v3.1 firmware file.

I think the next step needs to be revisiting the maps in my XEDE and making sure that I didn't create any problems when I was working with the boost leak. I think I'll also do compression and leak down tests just to be sure everything is OK.

 

this is good reading keep it up and of course good luck

 

Thanks for the encouragement! - I'm sharing this in the hope that others may benefit from what I find as I work through everything.

After more testing I've pretty much narrowed things down to the last .005" that was removed from the head, along with the higher torque specs I used. I'm guessing that I've crossed the magic threshold that leads into subtle detonation land.

While I really like the XEDE and it's software, data reporting with that set-up for both the ECU and XEDE is really limited right now. My biggest problem is no way to get any form of ECU based knock and timing information. It's such a big problem to me that I'm on the verge of pulling the ECU and XEDE and replacing them with a PowerFC stand alone plus the Datalogit box and software. I should even be able to drive the OEM boost controller if I set things up correctly.

To deal with the head problem, I've ordered a new JIC 1.2mm head gasket from Adam at Z-1, and it should be on my doorstep sometime today. I'll put it in over the weekend and hopefully that will sort everything out. The "extra" .2mm is supposed to be about .0078" so that should add back the space lost when the head was re-decked. Since the last .005" cut was a second decking, I'm not too worried about the extra .0028" adding too much extra volume. At least I hope not.

I'll add more once the new head gasket is in, and the car is running again.

 

Alright - everything is back together and I will be doing some initial road testing later today.

Here's a small "aside" that's just plain weird. The frist time I ever set up this car to replace my cam gears, I marked my timing belt with a small white stripe across the belt for each cam gear at TDC. With all the problems I've had, the head and/or cams have been out of the car 8 or 9 times. For all but 2 of those times, those original timing stripes have immediately cycled up to TDC on both cam gears when the car was prepped for the upcomming work.

The two times they didn't cycle up were for the second head gasket replacement (nothing was fixed or adjusted, just a head gasked was replaced) and the install of the HKS 280 cams. In both of those repairs, there was no long-term benefit to the car. When I set up to pull the HKS cams and put the Pipers back in, the timing marks returned.

A friend of mine has decided that my car is quite unnatural, even expressing an opinion of the up-comming repairs. This time around, he opinioned, the car seem to agree with what we are doing. I hope he's right - Wierd, huh?

 

How do you know if the ported head was done properly? That could very well be the reason for your low numbers.

 

Good question, but I've already put down 310 whp on the same dyno with that head and a bad head gasked - after I had the head re-decked the car hasn't broken 290 - but the head gasked now holds. I also had the shop who re-decked the head inspect everything to see if there were any other problems with the head.

I've got a friend willing to let me borrow parts from his Evo to test the coils and and MAF, and I'm going to be re-checking the AFRs and such today. I probably won't hit the dyno again though until I can figure out where the problem is.

 

Seems that the theory of less combustion space equaling less power is holding true.
Just a thought. How have you been making out lately?

 

OK - some better news - last trip to the dyno was better - about 300 whp but my torque was pretty low - 265 ft/lbs or so. I'm still working on a couple of details so I guess we'll see where everything lands. At this point everything seems to be running correctly (no big problems) but the car could use to spend some time with someone who really knows how to tune an Evo. I can dial in the ARFs and boost table, but I'm not comfortable doing too much with timing.

I'm frustrated enough at this point to just want to get everything dialed in and tuned so I can spennd some time on the track this summer. I'm scheduled for about 8 more track days and I really prefer track time to garage time.

 

More news. Last Saturday Al from Dynoflash was in town (at RS Motors) doing custom tunes for 8(?) local (and semi-local) cars, as well as several "drive up" off the shelf flashes. The local Subaru club was having a dyno day, so most of the Evos were road tuned. While I didn't sign up for the event, I did ask Al to take a look at my car if he had time. I know the timing map could use some work and I can't really see what's happening with my XEDE.

After watching a string of Evos put down between 260 and 280 whp with similiar mods to my car (less the ported head) it was my turn to hit the dyno. My car immediately put down 304 whp and then followed it up with 305. The kicker is that my OEM boost controller looks to have given up the ghost. The car wasn't building any boost until late RPMs. Without a spare boost controller available there was nothing more we could do so my car came off the dyno. Doing some additional testing once the car was off the dyno confirmed that the boost controller was the problem (and not the turbo).

My next step will be to install a manual boost controller and see where things go from there. While I will probably still need to do some timing work, it looks like my car is slowly getting closer to where it should be.

It was also helpful for me to see what a number of other cars with similar mods (or similair to prior stages of my car) were putting down to help provide a basis for where my car is actually at. While Ron's dyno seems to be pretty stingy with the big numbers, it's amazingly consistant.

An aside is that I changed up my intake set-up again. This time I kept the cone and base plate from the K&N Typhoon, but ditched the provided inlet pipe. Instead I installed the OEM rubber pipe; I've suspected the K&N pipe for a while, but didn't have a chance to test before now. The result was much improved low RPM driveability and idle (like the stock air box) with what felt like better breathing (and a few more HP) at high RPMs. It also solved a low speed BOV flutter that the K&N set-up had introduced. Not exactly the prefered solution for "fixing" an aftermarket intake, but better than no benefit at all.

 

Great info!
sorry I couldn't help out with the parts!
I will still try to make it happen for you in the future!
your numbers are killer on that mustang dyno!!
FYI for others: Stock STI made appoximately 220WHP and torque on that dyno!!

 

Thanks for the supprt - I should have a new Hallman boost controller here and installed by Thursday and hopefully I will be able to sneak the car onto the dyno to dial in the boost.

 

The car ran well at Mid-America Motorplex (MAM), but I could feel the missing boost. The new boost controller arrived on Tuesday and is now installed. I haven't had a chance to take the Evo out and dial the boost in yet, though - too many other projects that need attention.

I should be able to get some new dyno numbers early next week.

 

Cool, im going to that Dyno @ RS tomorrow at 2:00.