underpowered with dom1.5?

[spec_bg]

we will run em again from different rpm. .

i guess after reading the reviews on this turbo i had high hopes for it.im not saying my car is slow or anything just not as big of a difference as i was expecting.

on the vf i was dyno tuned and then had phatron tune it later on to try and get rid of some hesitation, i liked phatron's tune better, it was more fun. thats why i went with him again. i dont want this thread to be negative towards him,he's been helpful

can you compare time between one person log and anothers? like how long it takes from 4-6k rpm and compare it to how long it takes the other guy to go 4-6k? mine and northman log was similar in time too. a higher power car would make it to 6k faster wouldnt it?

say i went to same dyno. would it dyno at 350hp, but log 300g's or dyno at 300hp? trying to understand the whole g's thing

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[northman]

Originally Posted by spec_bg

can you compare time between one person log and anothers? like how long it takes from 4-6k rpm and compare it to how long it takes the other guy to go 4-6k?

That is the basis for doing airboy plots. If you know the weight of the car+driver, the time to accelerate will let you plot the power curves. Our cars are similar, so it should work well enough. Flat road and average of both directions would be best.

[spec_bg]

romraider wont let me do that, something about car definitions not being found. we downloaded the car def when we installed RR but something didnt go right. i can do everything else except use the dyno tab

[Phatron]

Originally Posted by spec_bg

we

say i went to same dyno. would it dyno at 350hp, but log 300g's or dyno at 300hp? trying to understand the whole g's thing

the g/s is a meaningless number between vehicles. it only means something on the car its on.

as far as dynos go....it depends what dyno you go on. Like the link i posted above from EFI and 310whp or Topspeeds 370 whp.....same boost.

[xluben]

Originally Posted by spec_bg

romraider wont let me do that, something about car definitions not being found. we downloaded the car def when we installed RR but something didnt go right. i can do everything else except use the dyno tab

Defintiely don't use the RomRaider dyno function. It does not work very well. Just pull a few logs from 2k-redline and then plot them with Airboy or Virtual Dyno (VD is easier). Then if you have a log from the VF car, you can compare. This takes the dyno variation out of the mix (as long as you both get good logs from flat roads and enter the weight info correctly).

Originally Posted by spec_bg

say i went to same dyno. would it dyno at 350hp, but log 300g's or dyno at 300hp? trying to understand the whole g's thing

As Phatron already said multiple times, the g/s is meaningless for comparing between cars. It all depends on the MAF scaling.

[Phatron]

here ya go. northman vs spec bg.....feel better now?

northman red, brandon black

[neorex]

[spec_bg]

hell yeah i feel better. i hope you understand why i was concerned.

thank you northman and phatron

[wrxsubiemod]

Phatrons the best : )

[Phatron]

I just posted this in the other 1.5xtr thread...but believe its suited here too

"Originally designed for our 2.0L customers in the UK, the Dom 1.5XT-R uses the Garrett GT 56.5mm turbine instead of the full 60mm turbine of the Dom 2.5XT-R. The end result is a slightly quicker spooling turbo while trading off some high RPM horsepower capability."

IMO there is no reason to run this turbo on a 2.5L.....10cm2.5xtr is what should be put on a 2.5L

The 1.5xtr is basically a 20gxtr with a slightly bigger compressor wheel that does abosultely no good cause the turbine is choking it.

[spec_bg]

what is the rpm spool difference between the 1.5 and 2.5 that you see when tuning both?

[punchjamesarnol]

I peak a little bit before 4K. From what I read I other post the 1.5 peaks mid 3000.... sorry (edit)

I start boosting right before 4k and peak at 4.5k. I realized that after looking at Ron's plot.

[Phatron]

[BigRob74]

Originally Posted by Phatron

thanks for posting that, seems the dom 2.5 is better for the bigger motor

[BlazeRex]

I hate when people expect a certain result from a car and then jump on the tune or parts when they dont get it. The car will make what it makes. Just cause one guy said his car made X whp and Y rpm spool on Z turbo, doesnt mean yours will do the exact same, or even remotely close. Everything from weather, compression, coil packs, clutch, etc can change the results.

Go through a dyno database and type in a certain turbo and compre a few cars equipped with them. You'll see what I mean. The graphs usually resemble each other, but are nothing like being exact. Sometimes even close to 500rpm+ spool difference.

[Phatron]

^ exactly. And people have to realize that folks like me or even big shops don't have time to test every single setup. Each person comes in with different parts and different running cars.

You can go on efis dyno database and plot up the 20gxtr, dom 1.5 and dom2.5 and depending on which setups you pick to plot against the others you can make a case for each turbo outperforming the others. But none of them have the same combination of parts or even the same boost levels.

[northman]

Originally Posted by Phatron

I don't want to sound like a homer, cause I have the 1.5, but the way you present that graph is a bit misleading. The 1.5 boost does not appear to be anywhere near maxed out, as evidenced by the flat, non-tapering curve. To look at that and conclude it has no top end capability would be a stretch.

[Phatron]

It was not meant to show top end capability....it was meant to show spool.

Brandon asked about spool so I posted a boost plot. Simple as that.

If I wanted to show top end capability I would simply post the turbine and compressor specs again.

[northman]

Originally Posted by Phatron

It was not meant to show top end capability....it was meant to show spool.

Brandon asked about spool so I posted a boost plot. Simple as that.

I agree, I am really responding more to the guy who posted immediately afterward concluding the 1.5 was not a good choice for the 2.5L.

I would love to see a family of curves that show different turbos maxed out on boost, to get an idea how much they can flow around redline.

[Phatron]

Just go on a dyno database like efis and make plots.

You will come to the conclusion that the turbo is not the only factor.

You can make a multitude of comparo plots that show the 20gxt, the dom1.5 or the 2.5 to be the superior turbo.

But in the end, the turbo specs should hold up to be true. A completely maxed out 20g should not make more power than a 1.5 and a maxed out 1.5 should not make more than a 2.5.

[climbhigh09]

I'm actually glad to see this thread after all the recent noise about the 1.5 being the best thing for the 2.5L since sliced bread. There have been some insane numbers thrown out for that turbo... faster spool and more top end than the 20GXT; making it a magical turbo that lots of people are jumping all over.

Blouch knows their stuff, and I'm sure the compromises for the 1.5 make it a really nice turbo (to the degree that I have one sitting in my garage for testing against my 20GXTR some day), but it's been painful to see all the spray about people expecting this thing to break the laws of physics when they strap it on their car.

In the end... pulling against a VF from <3.5+RPM with a larger turbo will always leave you in the dust, unless you're willing to push speeds WAY past what would be reasonable on the open road. New engine systems require new driving considerations, simple as that.

EDIT:

Originally Posted by northman

I don't want to sound like a homer, cause I have the 1.5, but the way you present that graph is a bit misleading. The 1.5 boost does not appear to be anywhere near maxed out, as evidenced by the flat, non-tapering curve. To look at that and conclude it has no top end capability would be a stretch.

whoa... didn't see the pick on my phone. I agree- you're trying to show a boost plot- my 20G hits 21psi before 3.7kRPM. Granted, I've done what I can for a quick spool, but this isn't pushing the 20 at all; is it really that close to a 2.5 on a similarly built system?

[V8 GTFO Lesbic WGN]

what is the latest on this?

[07VTRex]

i want to chime in an say that i am having similar experiences with my DOM 1.5xtr. I have had almost the identical discussion with Ron, as he also tuned mine.

I want to say that this turbo is not all its cracked out to be, and i like many others have fallen for topspeed's propaganda on this turbo.

While i like this turbo better than my VF, it didnt live up to my expectations. Topend is definetly better, i enjoy the linear power delivery, but the low end is gone, and i am starting to miss it. It became immedietly apparent when pulling a VF suby locally and me being suprised i didnt smoke him

I am hoping that meth injection is going to bring this turbo to life, and get close to the results we have been lead to expect from topspeed's testing.

*Ron, is there anyway you could add my dyno plot to the above with OP and northmans to get a 3way comparo going? I am just curious as well as to how mine stacks up.

i am REALLY hoping meth can get me in the 340-350 range, with hopefully more improvement in the midrange torque. Just hope the stock block will hold that much, we will see

[Phatron]

it takes a while to plot them up against each other. heres your plot....another with kelford264 cams and another on e85. Note on the e85 car....its only running 21psi since it has a stock map sensor.

2007 WRX 65mm DW750 Dom15xtr TMIC EBCS EXT 93 Oct



2011 WRX TBE Per72mm DW750 Dom15 GSEBCS PWTMIC TBE 264Cams 93 Oct



2009 WRX Dom15xtr10 DW1000 KS73 FMIC TGV AirP Ext MBC E85

[07VTRex]

thank you for posting that Ron.

When the time comes that i can ad meth to my setup, would you expect it to look similar to the e85 plot(3rd one down)? Better yet, when comparing meth to e85, how would you expect the plots to differ? It is obviously not going to shift the powerband like the cams will.

For anyone else who may be wondering, will alternate fuel such as meth or e85 do anything for midrange tq or earlier spool, i.e. can it shift the graph to the "left" at all? Or does it help with increasing power evenly, i.e. does it simply shift the graph "up"?

It seems all the plots share one thing in common: lack of midrange torque. Can more midrange boost be squeezed out with this turbo, given the right fuel, with boost tapering off up top, not unlike a vf turbo? Or is it better to not have a boost taper at all?

After getting used to this setup, i really like how the turbo does not "fall on its face" like the VF turbos do, however i miss the mirange punch. Can this turbo do both or is it simply mechanically not-possible?