Turbo recommendation for ~450 wtq? Stock location...

[tocinoman25]

Any chance youll try a dom 3.5xtr? Looks like ill hit my goal of 400whp for my daily leggy once i get my built sb. Glad i gave steamspeed a try although 1.5xtr wouldve been ideal but they lacked customer service at the time i was shopping. This is great data for sure and thanks for sharing your experience.

[rebourne]

SteamSpeed needs to make that 67+ in Legacy fitment, not the 71. I think they'd get alot more interest 'round these parts.

[Nightmaresmk]

Is it me or should this be a sticky. this is real life comparo This is some of the best information since the only change is the turbo.

[Rhitter]

Hi OB. On the exact same dyno as all of the above plots, I have driven the Tomioka GT28 making 381wtq and 395whp. I would say that the graph was very similar overall to the current Tomioka one.

 

I found it a bit laggy for my taste. Didn't mind it at all 'off the line' if I was in the mood to go all out. However, I hated the lack of punch if I'd go WOT at normal interstate cruising speeds, even in 4th but especially in 5th. Now, that setup did ok in the 50-80 and 60-80 time measurement by airboy (I always liked that thread as a decent measure of real world performance for those of us who don't track our cars). The actual values were: 50-80: 2.71s and 60-80: 1.58s.

 

I posted an airboy of may car on this setup earlier FYI. Because I was comparing to something Joe posted, it used the 'dynojet' setting which clearly bumped up the #s a bit. But that's the most power I've had.

 

You might want to balance your desire for max numbers with your desire for drivability. Reading the above you might not be happy with some of these higher HP setups.

[boxkita]

Is it me or should this be a sticky. this is real life comparo This is some of the best information since the only change is the turbo.

Probably should.

[jcole05]

You might want to balance your desire for max numbers with your desire for drivability. Reading the above you might not be happy with some of these higher HP setups.

 

Agree 100%. I am just admitting in the sake of full disclosure that it is *hard* for me to turn my back on the 'numbers' that Dom2.5 made.

 

But yes, pending upon today's final results (HTA71 from FP and 10cm Blouch 1.5xt-r), I am expecting to pick from one of these two turbos or the Blouch 1.5xt-r 8cm in the graphs above. My guess is that the HTA71 will spool the quickest but make the least power, the 1.5 8cm will be in the middle and the 1.5 10cm slightly to the 'right' in the powerband.

 

We shall see.

[jcole05]

Probably should.

 

A fellow Pac Northwesterner too and still lol-ing at my thread.

[rebourne]

Which ever turbo you pick, you should then repeat the whole process with ELHs!. I'm brilliant!

 

Seriously though, I'm guessing the 10cm 1.5xtr paired with a good elh will be the magic balance. Not sure compromise is even the right word here. Nearly 450 (maybe 450 uncorrected on the right day), and a fat torque band. But then again the HTA71 is supposed to be the shizzle on corn!

[Nightmaresmk]

ELH will pick up a little hp and decent tq spike.

[jcole05]

Any chance youll try a dom 3.5xtr?

 

No, I think I've pushed the limits already having to get this 10cm Dom1.5xt-r overnighted. Probably about time to let go so the shop can get on to some other customers and all.

 

I have to admit that this is addictive since it is so hard to really know what is and what is NOT helping one's car meet one's goals.

 

For example, I really would love to do an UEL for ELH swap once I pick a turbo and see the difference. I'd also love to swap my GSC S1 cam for stock and for the Tomei Poncam that fahr likes and see the difference.

[gkinslow]

I'm soaking in all the comparison data for my future plans. Definitely should be a sticky! Thanks jcole05!

[Gex]

I love my 3" Dom 1.5xt-r 8cm. What shop is doing all the work here? I perused the thread but must have missed it/not listed going through the thread.

[jcole05]

I love my 3" Dom 1.5xt-r 8cm. What shop is doing all the work here? I perused the thread but must have missed it/not listed going through the thread.

 

I haven't really tried to hide the shop's name but haven't talked about it too much either. Mainly, since I wasn't sure how this experiment would go, if there were issues/problems I didn't want to give people a bad impression about a particular place based upon one experience. But since they have worked well with me so far (and since the dyno plots actually state it in the corner anyway), it is PRE or performance race engineering in Portland.

 

The only other prominent subaru shop around here that I know about is Cobb Surgeline. They get great reviews but I wasn't too impressed when the guy on the phone told me they could make 'any' amount of torque from my 2.5L engine. I tend to think that this displacement 4 cylinder engine is limited at some level to a maximum amount of torque it can produce so I wasn't blown away by this answer (PRE tells me that they haven't seen a lot of 2.5L subies making *that* much more than the ~450 wtq I am looking for).

 

Anyway, that's the deal.

[boxkita]

Are they retuning for each new turbo? or just putting on the new one and leaving the original tune for whatever you started with?

[tocinoman25]

SteamSpeed needs to make that 67+ in Legacy fitment, not the 71. I think they'd get alot more interest 'round these parts.

When i was talking to Christian and Sam about making me a 67+ it was a no go...i was sad but who knows...if there is enough interest they may change their minds?

 

As for doing ELH vs UEL that shouldnt be a thought. If guys want to make power ELH all the way...bwahahahaha...spend all this money and then save for the distinct sound....cmon power and efficiency>sound.

 

Yes...sticky sticky sticky lol

[jcole05]

Are they retuning for each new turbo? or just putting on the new one and leaving the original tune for whatever you started with?

 

Definitely retuning for each turbo. Was just down at the shop right now. They are putting in the Blouch 1.5xt-r 10cm as we speak. It's going to make it to the dyno this afternoon but not be completely tuned until tomorrow.

 

I asked a few questions and their method seems to be to test each turbo to see if a moderate change in AVCS (intake obviously) settings makes a difference - interestingly, the Dom 1.5 8cm liked advancing the AVCS more than most other turbos I'm told - and then proceeding with a complete tune for A/F, timing, boost and all those other parameters most of you guys know a lot more about than me.

[fahr_side]

Luckily the header will give you the same bump in power on all of these turbos.

 

With AVCS tuning... I think there's confusion about the effects of more advance. While to a certain point more overlap improves VE (which improves air flow and torque), more will hurt spool, and earliest spool doesn't always get the best possible torque. On the smaller turbos more advance and overlap in the 2k4 to 3k2 range helps VE all the way up to the boost threshold level and more exhaust gas gets the turbo spooling sooner as a side-effect. I think with larger units their boost threshold is higher than the point at which you either have to pull back on advance and overlap or hurt VE and torque. This is where the D-AVCS heads really shine.

 

Sent from a device using some software.

[jcole05]

Fahr - you are really making the enormous geek that lives inside of me want to learn to tune. I can see why it is so nice to have that skill set as you can play around ad nauseum to find the perfect setup for your particular hardware and the way you like to drive.

 

As good as I'm sure a protune obviously can be, say, compared to an etune done by a novice (and the immediate feedback a dyno provides must be extraordinarily helpful), I have no doubt that even protuning is undertaken less as an art but more as following a basic cookbook to pump out safe, reliable tunes making decent power.

 

But if there is no other lesson from this thread about my own personality and approach to my car it is that I really like taking data and trying to optimize a set up.

 

PS - how much interest is there in seeing a 21 psi map for all of these turbos? The shop is doing both 21 and 25-26 tunes (the latter at least for the turbos that can get to these higher boost levels). I'm happy try to undertake the effort to get these printed out and scanned in - but only if people care.

[LatentWagen]

As good as I'm sure a protune obviously can be, say, compared to an etune done by a novice (and the immediate feedback a dyno provides must be extraordinarily helpful), I have no doubt that even protuning is undertaken less as an art but more as following a basic cookbook to pump out safe, reliable tunes making decent power.

 

The benefits of a dyno are clear, for sure. A lot of people put too much of their tuning time into dyno time, however. Dialing in a tune on a dyno is necessary if you're trying to compare how a setup performs, relative to another one (like this thread), and it's everything if you're trying to make a big number or a pretty graph... but a dyno can never replicate real world conditions, which change all the time.

 

IMO, no tune is fully complete until it's finished on the road. That's something that an e-tune can better provide, since you'd take logs of your regular day-to-day driving conditions. Hills, wind gusts, traffic, and everything. Not too many tuners want to sit shotgun for your daily commute to dial in those finer points

 

PS - how much interest is there in seeing a 21 psi map for all of these turbos? The shop is doing both 21 and 25-26 tunes (the latter at least for the turbos that can get to these higher boost levels). I'm happy try to undertake the effort to get these printed out and scanned in - but only if people care.

 

Yes

[jcole05]

Wow...shop is thinking that this turbo is just the perfect match for my setup, cams, etc.

 

I am so happy I went with my gut and got that 1.5xt-r with a 10cm housing shipped my way and that PRE was willing to add it to the list.

 

They have now been kind enough to test 9 turbos for me so obviously I had to ask very nicely for the owner to acquiesce to test one last one since we'd started out planning to test 5.

 

But for whatever reason, I just couldn't let go of Topspeed's test from many years ago (detailed on Nasioc) in which they didn't see a decrease in spool from the 10cm Dom1.5xt-r versus the 8cm. Now, that test wasn't perfect because the runs were done on different days and the 10cm run was at slightly cooler temperatures. But it just seemed from my car's boost curve on the 8cm Dom1.5 that something was leading to some inefficiency due to the unusual pattern present after it reached ~24 psi.

 

Anyway, drumroll please. The last turbo was by far the best and I am going to be leaving out to door as one very happy customer.

 

 

Blouch Dom 1.5xt-r, 10cm housing

 

[jcole05]

Some more data for those interested. I will be leaving on Monday with my car and with a whole lot of dyno plots. For example, I haven't even seen the plot yet for the Steam 67 (non+) or the FP HTA71. I'll definitely be posting more dyno plots in the days to come, including 21psi performance.

 

I've said this before, but to clarify, all dyno plots I've shown and will show are CORRECTED for atmospheric conditions. This should allow as close as possible to a true apples-to-apples comparison. The shop didn't even install my carbon fiber drive shaft in the middle of this experiment so it wouldn't potentially alter the findings. They even apparently tried to control for factors such as the amount of particulate matter in the air, etc. This was as 'scientific' as they could make it, I'm told.

 

 

First - boost and AFR for the Dom1.5xt-r, 10cm housing.

 

 

 

Now- boost curve for the Dom1.5xt-r, 8cm vs 10cm housing.

 

 

 

Now- boost curve for 5 selected turbos (out of 9). Interesting to see the steam 67+ trying to keep up with the Dom1.5s but eventually peeling off at about 3750rpm.

 

 

Now- comparison of Dom1.5xt-r, 10cm versus 8cm housing, wtq and whp.

 

 

 

Finally- comparison of Dom1.5xt-r and Dom2.5xt-r, each with 10cm housing.

 

[Gex]

Damn that is impressive for a Dom1.5xt-r. Congrats and enjoy it! What a beast.

[joeleodee]

I knew that 1.5xtr 10cm was going to be impressive. Like I said earlier, you see it give up a little but up top to the 2.5xtr, but not enough to disregard the improvement in spool. I think you have a winner here. From the start, I mentioned either that one or the 20gxtr would have been my choice for these power levels in a stock location. Glad I could have been a part of this. Thank you.

[jcole05]

I knew that 1.5xtr 10cm was going to be impressive. Like I said earlier, you see it give up a little but up top to the 2.5xtr, but not enough to disregard the improvement in spool. I think you have a winner here. From the start, I mentioned either that one or the 20gxtr would have been my choice for these power levels in a stock location. Glad I could have been a part of this. Thank you.

 

You've been a great help Joe. Thanks to you and a lot of other folks around here, I've learned a ton and had a great time in the process.

[rebourne]

wow that 10cm 1.5xtr looks amazing! Have your cake and eat it too Turbo!