Tjabo

It doesn't seem like I am using the search feature right, because I get very few hits, but maybe someone here can help me out.

What I'm confuesd about is that the compressor map for a 50 trim t3/t04e seem to look quite a bit better (for a 16 valve 2.0 liter) than the 57 trim map, and yet it seems on here that people feel the 57 trim to operate better. It looks like the 57 trim would be less efficient, and would be more prone to surge.

If it's just one of those things where practice doesn't follow theory, that is good to know, but maybe there is an explainable reason, too?


Modified by Tjabo at 5:51 AM 9/2/2006

Whiteintegra

i think people pick the 57 trim b/c it also give you room to expand in case you want more power down the line. I personally am going to be using a 57 trim 60/48 b/c i like the torque it makes.

JoePSI

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Whiteintegra &raquo;</TD></TR><TR><TD CLASS="quote">i think people pick the 57 trim b/c it also give you room to expand in case you want more power down the line. I personally am going to be using a 57 trim 60/48 b/c i like the torque it makes.</TD></TR></TABLE>

exactly 57trim supports more power, that is the reason i chose it for my setup

here is a full write-up on a dsm forum about the the 50 trim

http://www.dsmtuners.com/forum...53719

hope this helps.

Tjabo

Thanks JoePSI, that was an informative writeup!

Still though, it leaves me wondering why people are more interested in the 57 trim. When I compare the compressor maps, the 50 trim not only has less tendency to surge, it has much more potential for big HP numbers.

I'm still not getting it. . . But thanks guys!

Soccerking3000

y not post the maps up here so we can take a look at them, i thought the 57 trim flows like 8 more lb's of air a min?

Tjabo

I'm new to this board, but assuming I can figure it out, I'll do it! Maybe my 57 trim map isn't correct or something. . . .

Hopefully I'll have a chance to take a crack at it in an hour or so.

eastbay92cx

There is a tendancy on this board (and to some extent with honda owners) to use really large turbos, or turbos that are too large some would say. Yea you can consider 'room to grow' or if you might be wanting more power down the line, but if you have a pretty good idea of your power goals, then looking at the maps and selecting (one of) the smallest turbo that will meet those goals is the right idea. Low end torque, area under the curve are very important in a street car, unless you're only interested in all out performance in the highest part of your powerband.

Someone else will hopefully chime in with some good advice or real-world experience, as I haven't used either of these turbos myself.

http://not2fast.wryday.com/tur...shtml

Something like this will give you a plot for the maps, if you can come up with good numbers to fill in.

A good board for in-depth technical discussion is pgmfi.org, I'd suggest that place for some good reading and perhaps more advice. Good luck.

Soccerking3000

well let me look up some of the specs, as for posting the maps up, if you have them on your computer you need to host them somewhere and then link them, but if they are on a website you can just link the maps pictures

Soccerking3000

COMPRESSOR SPECS:

flow: 46 lbs/min 588cfm

50 TRIM WHEEL

TURBINE SPECS:

.63 A/R HOUSING

STAGE 3 WHEEL

oil lubricated centersection.

supportable of 450whp!


COMPRESSOR SPECS:

flow: 53 lbs/min 678cfm

.60 A/R HOUSING

57 TRIM WHEEL

TURBINE SPECS:

.63 A/R HOUSING

STAGE 3 WHEEL

supportable of 475whp!


thats what i found it flows 7lbs more

Tjabo

Eastbay92cx, thanks for the links! I had forgotten about that turbo calculator, and I'll definitely check out the pgmfi.org.

I messed around with the calculator for a few minutes, and with numbers that *MAY* have been semi-accurate, everypoint I plotted on the two graphs was in a more efficient area on the 50 trim map. . . . Clearly I've got some hours to spend with that thing!

Soccerking3000, those look like some specs I've seen on cheapturbos.com, and after looking at the maps I have, so far I can't figure out how they reach those conclusions.

As for the maps themselves, so people can plot out some points, here is the 57 trim map:



And here is the 50 trim map:



Thanks again for all the input so far!

Soccerking3000

wow the 50 trim is better pretty much everywhere, i wonder why that is, and now i am wondering why i have a 57trim over a 50 trim lol, its seems that the 50 trim has much flow even at high boost levels too, weird

JoePSI

are those graphs right? lol

I think they are swapped

Soccerking3000

give me a sec too see if i can find some more maps... cause that would explain it if they were swapped...

AbitAvenger

okay im freakin lost here. something is up

Soccerking3000

57 trim:


50 trim:


so my conclusions are is that the 50 trim is 100% better pretty much lol

AbitAvenger

WOW i just might change my mind on the 57 trim...

EDIT: The 50 trim on my motor would be WAY more efficient, I'm def going 50 trim 63a/r

Tjabo

Hmmmmm. . . . Based on what I thought was a preference on here for the 57 trim over the 50 trim, I actually was considering a 57 trim even though the tables for the 50 trim seem way better. Now you guys have pretty much erased that thought from my head!

Is it possible that there's someone on here who has tried them both and prefers the 57 trim in real-world conditions for some reason, or was I just imagining the whole thing? LOL. . .

Thanks again!

Soccerking3000

i have a 57 trim now, but hell if someone wants to trade me for a 50 trim lol hit me up and i'll tell you, i'll even go dyno it to see how it compares at like 15 psi 20 psi and 25 psi

Blaze45

My .57 trim pulled VERY hard on the top end. Didnt seem like it untill I raced a few people....

Soccerking3000

well so does mine it pulls like a bat outta hell but by looking at the compressor maps, the 50 trim should pull even harder and be more efficient in the upper rpms

KeyserSoze

I asked the same question in the holset thread a while back and blundy gave me this explaination........

https://honda-tech.com/zero...ge=47

95GSRTT

i didnt really see anywhere, where he has any basis for what hes saying though. He just said hes seen this and seen that. Wouldnt the maps be a lot more accurate?

dpetro1

i have always heard that the 54 trim was less effecient than the 50 trim and i never understood why. now you guys are bringing up the same point about the 57 trim. i mean if the compressor map says the 50 is more efficient than its hard to say otherwise. how could that be possible?

i mean i know compressor flow isnt the only thing that makes power. do you guys think the combination of turbine and comp. wheels have anything to do with it?

it has always seemed that the 57 trim does work well with our setup and has become the most recommend here on h-t for your typical 300whp b-series build. thats kinda why i chose the sc34 for my setup.

dpetro1

here is something else i ran into...on the precision site it lists all the compressor wheel sizes for all trims in a chart. i noticed the 50 trim has the smallest inducer @2.123" but a larger exducer @3.00". where as the 57 trim has a 2.230" inducer and 2.950" exducer. the 54, 57, and 60(sc44) all have the same exducer. it bumps back up to 3.00" with the sc60. maybe no big deal really until i found this on the garrett site...

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TurboByGarrett &raquo;</TD></TR><TR><TD CLASS="quote">The trim of a wheel, whether compressor or turbine, affects performance by shifting the airflow capacity. All other factors held constant, a higher trim wheel will flow more than a smaller trim wheel.

However, it is important to note that very often all other factors are not held constant. So just because a wheel is a larger trim does not necessarily mean that it will flow more. </TD></TR></TABLE>

i know this sounds pretty simple but considering the exducer size isnt being held constant maybe that has something to do with it. or am i just stretching here???

Soccerking3000

even comparing the inducer/exducer then 50 trim is almost identical there is about a 1/10th of an inch difference between the 2