Comparing the three housings on the dyno would be kool. Same injectors is good. Same tune is not so good as it might be best to adjust fuel and timing tables after each housing swap to optimize the tune.

Also, keeping the boost level the same might not allow the different housings to stand out against each other. For, example the 11.5 hsg. should allow you to run higher boost, or more timing than the 9.8 housing on the same fuel.

It is proven that a 10.5 hsg. will produce more power than a 9.8 hsg. That's why guys with 2003 Evo's switched their 9.8 housings to the better flowing 10.5 units. But, to maximize the power potential of the 10.5 vs. a 9.8, a retune was needed.

 

The car will indeed be re-tuned and on e85 however I want to see a direct no bias comparison. These pulls would be done at a moderate boost level and only completed pending safe a/f and knock.

 

Yeah that's good, but what I am getting at is this: If you swap from a 9.8 to a 10.5, and finally up to a 11.5 turbine shell, the AFR's are gonna lean out considerably with each step up in cm3. So, you'll have to adjust the fuel table to keep AFR's the same when going from one housing to another even given the same boost level. So, in effect you won't be able to keep the same tune when doing your housing swaps anyway. Also the 10.5 and 11.5 housings will take higher boost and/or more timing than the 9.8 would before exhibiting detonation, given the same octane, ambient air temps, atmospheric conditions, and elevation level.

You're never gonna find out how much more power the 11.5 housing is capable of delivering if you run it with the same tune(fueling, timing, boost) that is optimized for a 9.8 housing or vice versa.

 

unless the boost level changes, you will not lean out considerably. the bigger hotside will shift/change the power band, and help you hold the boost for a longer time, especially at the higher rpm. the higher rpm is whats going to lean out, however, you would have already passed the peak power at that point.
the less backpressure in the housing will allow you to increase the timing by a point or two, without needing to lean it out.

 

Perhaps you are right about boost and AFR's, although it is debatable. But when you go from one housing to the next you will have to adjust boost levels anyway as a practical matter due to differences in actuator rod length. At least this is true when going from a 9.8 housing to a 10.5 unit. Correct me if I am wrong as I am going strictly from memory.

 

If BaLListic were to swap his old 9.8 housing onto his new IX turbo then he would have to run the IX WGA with the 9.8 housing, because the VIII actuator won't work with the IX compressor housing. Also, the 9.8 housing is considerably smaller externally than a 10.5 housing and sometimes a particular actuator rod length that works with a IX actuator on a 10.5 housing won't mate up without trimming the end off the actuator rod. These seemingly minor adjustments in actuator rod length and angle change the turbo's wastegate spring pressure.

Changing the wastegate spring pressure has a direct impact on the boost levels seen not only at the topend but in the lower and upper midrange as well. Boost delivery plotted against engine RPM will change considerably. I was just trying to point out that it is pretty hard to control and isolate all the variables when doing housing swaps. For instance, the tune might lean out in the midrange and not only at the topend as you'd think it would. For example, it is easy enough to keep the peak boost level the same, but each housing swap will require adjustments to actuator rod length and not merely the boost controller knob.

So, eventhough the peak boost level can be kept flat, the rate of spool will decrease as each looser("larger") housing is installed. So the boost plot will change in the midrange and not only at the top. With the smaller housings shaft speeds will be much higher in the midrange and thus the turbo will reach higher boost levels sooner and be maintained across a wider RPM range.

EDIT: Sorry if I have veered this topic off course. I will shut the f**k up and climb back down into my bunker as of now.. I realize that I am the oldest living EvoM member. But that's another story. Ha Ha Ha LOL

 

Maybe to reduce variables a little when testing 9.8 vs 10.5 vs 11.5 the WGA preload can be adjusted so that they all have the same boost with just the WGA, then target boost is adjusted with the boost controller.

I might buy one of this housings in the near future as well.

Cheers,

Ricardo

 

Ok i backed out... Decided I didn't want to waste the money on something that wasn't yet proven....

 

If anyone cares, I found my boost leak

 

Yes, to make a meaningful comparison across three housings you'd have to adjust the preload to the same level first on each one and then dial in the same peak with the MBC. It seems like a lot of hassle.

 

So where was it Ramses?

 

My compressor cover. Time for a new seal.

 

Hmm, I wonder if you had that leak ever since you installed the anti-surge cover, and you just hadn't noticed it until now?

 

Well here is a funny story... I installed this cover just over a year ago right when the cover came out from FP to test it with Aaron. They had done the cover on a couple E85 cars, but not pump gas cars. So went to install it and it didnt want to fit on the housing with the original seal. Tried some seals we had laying around at work and none of them wanted to fit with the housing. Then I got the bright idea to just leave it off and hope for the best...Well that went well for about a year, until 2 months ago when I went to the dyno and apparently thats when it decided to start leaking. I made 385 last summer with the housing at 27 psi on a stock unported exhaust mani and QTP dump without this dang seal in there. When I went this last time a couple months back I wouldnt boost over 20 psi. I made 350 @ 20 psi which is good for the new setup, but wasnt able to make anymore boost with the tru boost maxed out. So changed the WGA as we thought it might be that, but did a boost leak test on Saturday and found that it was coming directly from the line up dowel pin on the comp cover... So I will be ordering up a new OEM seal and get her back up to 28+ psi and see what she's got.

 

^you may have better luck getting the o-ring from fp.

i dont think mitsu would sell that o-ring, since the turbo isnt really serviced on the comp cover.

GL, aby