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compressor map help


Vejigante

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At this moment im stuck triying to figure out which turbo will fit my aplication, but before hand im relatively new in the turbo world, just triying to avoid carpet bombing from people with more experience. Now what im working on its been done, im talking about a stoker turbo setup, yes theres a lot of info out and belive me im been doing some research in the small time i have left and its takes a lot of green guys cuz Im building this thing from the ground up. My issue now is trying to figure out a good turbine for this setup (t3/t4 combo, t3 or t4). At this point i just see numbers and equations and stumble in a quite few of them including calculators for boost, cfm and so on so on, the more i look the more complicated they get. until now i had play with garrett and turbonetic nunbers they (look the same) some others more simpler like Joseph obernberger at lovehorsepower.com and some places looking for compressor maps and my numbers differ from each of them. one of my main problems is getting pressure ratio some people use simple calculation as 141.7+psi/141.7 (aparently omiting factors like altitude, elevation and psi loss) others use TTc=P2c/P1c. To make the long story short if somebody with more expirience can shed some light of how to get the apropiate calculations ill be depply appreciated. Just need formulas not just use this turbo, this brand and so on, thanks

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It's not as hard as you think, at least to make a good estimate.  Figure out how much airflow you need based on your displacement and power goal.  Use that flow and pressure ratio against the compressor map and make sure you stay within the higher efficiency areas at your power peak and midrange.

 

You didn't say what engine you are using, but there are only a few options for turbines, so you can choose one that supports how your engine produces power.  A stock L28 does well with 0.63 T3.

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Even up to 500HP to the rear wheels JeffP showed that the 0.63 housing on a hybrid setup was not restrictive. All you do with a bigger A/R is cut your usable full boost window! He went to 0.82 simply because it wasn't available in 0.63...at that time.

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  • 2 weeks later...

http://atlanticz.ca/zclub/techtips/turbo/turbomaps/index.htm

 

The above link has a pretty good explanation of what to look for in a turbo compressor.

 

It does not show the GT 30 or GT35 ball bearing turbos though.

 

I think the 3076 would be good compared to the GT35.

 

Personally and for the money a T3/T4 .50 Trim E series compressor w/.63 AR stage III turbine would be ideal.

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1.06 A/R is way too big...

 

Depends on whether it is twin scroll or open scroll.  I ran a 1.06a/r T4 TS on my 2.0L EVO and saw 30psi@4K rpm in 3rd gear with a GTX3576r.  I currently run a 1.01a/r v-band TS (equivalent to 1.01a/r Open scroll) with a GTX3582r on my 2.0L EVO.

Edited by 240Z Turbo
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Here's my take-

 

I road race in GT-1 with a v6 turbo car and my team holds a podium title in the 2014 SCCA National Runoffs. I know little to nothing about drag racing, nor do I care about peak HP numbers vs usable for road racing. I know in drag racing, peak numbers may be more important. So it depends your application.

 

I've used a GT35 with every a/r and now run a gtx30 .63 t3 flange. The spool is about 800rpm earlier than the gtx35 and much more usable powerband for my application. Peak HP is still the same with the smaller frame. Garrett under estimates their range of efficiency for obvious reasons, but I've yet to blow a turbo in years with the type of use it is subjected to (40 minutes @ 25psi. on 100dg.f day).

 

I generally don't like lag. Moving foward, I may even use the gt29x and hope the power band start at 2800 or less.....wishful thinking.

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Hoover, Good to see you are still involved in the Z community.

 

When I went from a GTX3076r to a GTX3576r on the EVO I lost no spool and gained 30+hp on the topend using the 1.06a/r T4 TS turbine housing.  What is the discplacement of the V6 running the GT30 and did you go from a 3076 to a 3582?

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James,

 

Mid-life crisis really.

 

I just got back on the forums; figure no one knows me.

 

I started a thread putting one of my Z's back together-

http://forums.hybridz.org/topic/121447-back-at-it/

 

I will probably build a second Z with an RB conversion next. Things seem much more bolt-in nowadays. I still all the parts I purchased from you back-in-the-day.

 

My motor is v6 3.0ltr. I've used GTX3582 T4 1.06 a/r and now GTX3076 T4 .63 The 35 makes more peak hp, but if I push the duty cycles a little up top, I can make the same peak hp- 584whp. The difference is mid-rangee. I've datalogged and dyno tested both turbos and the smaller turbo/ar are much better for road racing. It takes 24 psi. for the smaller turbo to make 580hp and 21 psi. for the gt35 to make the same. If I ever get to build an RBZ, I will also use a small frame turbo for having fun on the street. The newer X series turbos are very good. I've yet to try the BW turbos, but the seem interesting. Garrett has been trying to fill all the sizes in between like Precision and it's getting a bit overwhelming to keep up.

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I'll give you a call next week because I have a closet full of shiny new RB parts that need a home.  Below are some VD results on 93octane comparing the GTX3076r vs GTX3576r on my EVO both using the 1.06 a/r T4 Twin Scroll from ATP with no other changes.  While we can debate the hp and torque results because the 35 ran slightly higher boost, what is not debatable is the GTX3576r consistently spooled as fast, if not faster, than the GTX3076r.

 

NOCAT_GTX3076r_vs_GTX3576r.jpg

 

Here are some more interesting results when I ran the GTX3076r.  Below are results when I ran a Revhard cast manifold using a T3 open scroll housing (0.63a/r and 0.82a/r) vs a short runner twinscroll manifold and the 1.06a/r T4 TS with no other changes.  This is more of an argument as to why you should run twinscroll vs open scroll and I should point out the Revhard manifold is not the best design for an open scroll setup.

 

63vs82vs106.jpg

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Thanks for the call, James. It's been yet another life time!

Funny, we've known each other for so many years and never met, but always felt that I had a bud out there I could talk turbo Z's with!!!! How cool is that!

 

That's great information! Thanks for sharing. It makes sense that spool would be nearly identical, since the turbine side is the same.

 

The 82 compare to 76 with .63 ar is the main difference and depending on track configuration, I might even prefer the 71.

Power makes a difference when racing in gt-1; especially at Laguna Seca. The top tear runners are 850hp and in the straights, HP rules there. It's just trying to find a balance of where power is needed.

For street cars, I'll probably use the new generation gtx29 even on an RB. If I can get spool at 2500rpm, it will be a fun car.

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  • 3 weeks later...

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