MIAPLAYA

iTrader: (3)

Except for the fact the 62-1 will out flow the GT35 but hey who cares about that. Theres also the option for a GTK turbo which will outperform the GT35R in every way but it will be at least a month till thats available. Again the 62-1 is what I would do.

taurran

iTrader: (18)

Put your car on ice and wait for a GTK turbo and external wastegate.

doug

iTrader: (5)

turbonetics guys pushing for turbonetics.. no.. never...

i can just see it now everytime a APS vs TN debate breaks out..

"well if APS is better? why is it that the only guy who made 450 whp on a APS ST kit is running a TN Turbo"

JoeDirtPharmD

iTrader: (9)

I'm convinced that would be more $$ than I have at the present time

Nealoc187

Compressor map school is in session.

Let's examine your claim for a second. You are right, the 62-1 does have more ultimate flow @ 65% efficiency (considered the "end" of a compressor map) than the GT3582R does. A whopping 2lb/min more (63lb/hr vs 61lb/hr) at 20.5 and 23.6psi respectively... Wow how useful for him. If he decides to crank his boost up over 20psi your statement might be beneficial - except that at the craptastic efficiency he'd be running both turbos at out there he'd be creating so much heat that he'd want to have switched to a larger compressor anyways. So your point is moot. Thanks for bringing it up though.

Now lets examine the compressor efficiencies in the range that he's actually using - i.e. what matters to him not what some hypothetical ill equipped setup would see.

Maximum efficiency: GT3582R = 79%, 62-1 = 76%. GT35R winner.
Maximum flow @ 9psi @ 65% efficiency: GT35R = 53lb/min, 62-1 = 53lb/min. A wash.
Max flow @ 9psi while maintaining 70% efficiency: GT35R = 49lb/min, 62-1 = 46lb/min. GT35R winner.
Efficiency @ 3500rpm: GT35R = 77-78%, 62-1 = 68%. GT35R winner.
Effic @ 4000rpm: GT35R = 78%, 62-1 = 73%. GT35R...
Effic @ 4500rpm: GT35R = 79%, 62-1 = 78%. GT35R...
Effic @ stock redline: GT35R = 76%, 62-1 = 74%. GT35R...
Effic @ 7000 if he has a raised redline (not sure if he does, but many people do): GT35R = 75%, 62-1 = 72%. GT35R yet again.

So what have we learned here? The GT3582R outperforms the 62-1 in every category in this application except one in which it was a tie. We also learned that the ultimate flow of a compressor means precisely jack when you are comparing how "good" one compressor is to another. Efficiency at your desired boost level is the name of the game - and the GT3582R wins at this game without question or qualification.

Compressor map school dismissed...

What else is there? Well there's the fact that both the wheels on a GT3582R are lighter than the 62-1 and any of it's optional O, P, or Q turbine wheels. Which means quicker spool. Also, there's the fact that the GT series turbine wheels are just plain more efficient than the O, P, Q trim turbine wheels - also contributing to quicker spooling and reduced lag, both in RPM and in time to spool.

So which turbo is better again? Also which is cheaper? A new GT3582R center section at approximately $1000, or a whole new 62-1 ball bearing turbo at $1600 someone said earlier (first one I found was $1775 and I'm not inclined to look much further) - then he'd have the additional (albeit minor) expense and inconvenience of needing to weld the elbow onto the compressor housing. Heck he could probably purchase a brand new GT3582R turbo, housings at all, have the compressor polished, the turbine ceramic coated, weld the elbow on the new turbo, and still cost less than a 62-1.

Speculation. It may very well be better than the Garrett GT, but then of course it's going to cost more, it's performance is unproven and will remain so for quite some time until folks not on Turbonetics' payroll get to review their performance, and it isn't even available yet.

You'd be making a decision which would get you a less efficient compressor, more heat, slower spooling, more lag, and inferior power production. Oh yeah and it apparently would cost you at least 60% more at $1600 vs $1000. An excellent choice if you like buying worse products and paying more money for them.

To the OP - I'm sorry I made this long post whoring up your thread. I just get annoyed when people who clearly don't know what's what with regards to a certain topic decide to post their brand-biased, ill-informed, barely researched opinion and want others who are seeking good information to consider it good advice. As a result of this lengthy post, hopefully you or anyone else reading this thread now knows a little bit more about the subject and can make a better informed decision on what to spend your hard earned money on.

meatbag

iTrader: (9)

I would like to know how you are figuring efficiency off of engine RPM for the turbos

Nealoc187

You calculate the pressure ratio and the mass flow rate at whatever RPM (using VE, RPM, displacement, etc) and then plot them on the compressor map and you can see where in the efficiency islands the plotted points lie. The compressor map is just a plot of PR vs MFR with the points of equal efficiency connected.

chimmike

iTrader: (7)

+1, I don't like majestic or phoenix. I've had great experiences with ATP.

just buy a new turbo, and if your motor is built, go for a slightly larger hybrid unit

chimmike

iTrader: (7)

hence the time you have to wait for the turbo to come out anyway, it'll allow you to save up for it

doug

iTrader: (5)

[peter from family guy] neal you are a ***** a filthy dirty *****[/peter from family guy]

meatbag

iTrader: (9)

Yes but you need to know the bhp level at each RPM you are plotting, which can vary greatly. Generaly engine setup will affect turbo efficiency as well as other factors. I know how to plot compressor maps but I dont see how you can compare them like that without more information.

meatbag

iTrader: (9)

ANy reason you dont like phoenix turbo? ATP has a higher markup for the exact same product, both dropshipped most of the time anyways?

chimmike

iTrader: (7)

I've had bad experiences with them. So have quite a few other people I know. They were great about 4 years ago, but went to hell. I've seen it happen to some good sites......aj-usa.com used to be excellent too and they went down the crapper.

Nealoc187

You can calculate the estimated BHP at the various points using brake specific fuel consumption and air fuel ratio. That's one way of doing it and the way that the books I've read on the subject said to do it. Of course all of this, my previous posts included, makes a bunch of assumptions and estimations using "accepted" or "average" values. As you know all of these equations and values are really just an "educated guess" sort of thing and that you can't really calcuate he actual output of an engine with just a few simple equations - but you can get a good idea of what it will produce and a good idea of where in the efficiency islands your setup is going to fall.

The basic point I was trying to convey in a nutshell was that a) the GT3582R is a more efficient compressor in almost every spot possible on the compressor map for the boost levels being talked about here, and that b) the maximum mass flow rate of a compressor at some super high pressure ratio doesn't tell you anything about how "good" a compressor is for an application using a drastically different pressure ratio.

If you're wondering about how I did the calculations for all the plot points and what not: I didn't. I did them once for a couple maps when I was sizing a turbo for another application and I don't want to do them again. I've got a computer program which does them for me now. I just input values such as pressure drop, ambient temp, displacement, boost pressure, RPM, and that sort of thing.

MIAPLAYA

iTrader: (3)

+1 Furthermore his sig says he is making 450 WHP. Which works out to ROUGHLY 515 bhp. Plot that on your magical GT35 compressor map. Actually I'll do it for you. Notice on the 62-1 he would only have to run a 1.75 pressure ratio to make 515 BHP worth of air (assuming roughly 10 BHP per lb/min of air). On the GT35 compressor he would have to run higher then 1.75, more like a 1.8 Pressure ratio to get the same amount of compressor efficiency. BTW its 65% on BOTH of them. So he'd have to run over a half more pound of boost just by using the GT35 to achieve the same efficiency? How does that make the GT35R more efficient. Mind you I'm only talking efficiency at HIS peak BHP. I don't know what boost he is currently running to make that amount of power. I can only assume its 9-9.5 PSI

MIAPLAYA

iTrader: (3)

It would nice if he had a dyno chart showing his hp, tq, boost, and AFR by RPM as opposed to making generalized assumptions.

Nealoc187

I'll agree that I didn't calculate for the same HP, I calculated a given pressure ratio. However, even if we use your method and calculate based on a horsepower number and vary the pressure ratio to attain that HP#, we still have the same basic results as before. The GT35R is still more efficient at every point on the map than that 62-1 is, except right at redline where they are exactly equal - hence it's still the better compressor for this application. My original points still stand. The GT3582R is a better compressor in that it is more efficient almost everywhere, it's maximum flow rate doesn't have anything to do with his setup, it is lighter and as such has better spool characteristics, it creates less heat (because it is more efficient), it requires less work to install, and finally - it's cheaper. Why would he go to an inferior setup and pay more money for it, when he can get a superior one and pay less? Doesn't make much sense to me.

Nealoc187

I agree, that would make the calculations quite a bit more accurate.

MIAPLAYA

iTrader: (3)

Well again thats assuming his running a pressure ratio that fits into that "more efficient" portion of the map. If you plot it strictly based on his BHP peak then the compressor have identical efficiency. In all honesty if he is only running 9-9.5 PSI of boost and making 515BHP he is not even on the efficiency island of the GT35 at peak BHP and pressure. He is at least still on the 65% band of the 62-1 at that point though. Making the 62-1 a more logical choice if again he is only running 9-9.5 PSI of peak boost pressure. To be more efficient as you stated on the GT35 he would have to run much more boost.

Nealoc187

The whole GT35R map is more efficient. There are a couple very small areas in which the efficiencies are equal, but there is virtually no place on the map that a 9-10psi 500hp setup would benefit from the 62-1 over the GT35R except right at redline where it's pretty much a wash, and is dependent on variables which we can't simulate without having more info.

Everywhere else on your plot, the GT35R is more efficient - from like 3000rpm on up to redline. Redline is the only place at which they are equal.

Yes you are right that if he is making that 515bhp at only 9psi on the GT35R then switching to a 62-1 would have him compressing air more efficiently - at redline only though (and the last couple hundred RPM before redline). Everywhere else, the GT35R is more effficient.

As you stated though, this is all conjecture without an uncorrected dyno plot showing boost, afr, hp, tq, and rpm. What isn't conjecture though is that overall, the GT35R is a more efficient compressor across most of the map, with the only exception being the absolute extreme right edge of it, where it is highly setup dependent as to which is better, if either.