Turbo Selection

[leahyz]

Hey All. I am new to this forum, but not to the SHO. Some of you may know me from the SHOtimes list.

Anyway, I am working on specs for a custom turbo setup. i am going to be doing all the fab work by hand, and hopefully all of the tuning as well. I am working out which turbo to use though. I am looking for input from people with turbo'd SHO engines mostly.

I have spent a lot of hours looking at turbo maps, and it seems there are a lot of descent choices. Let me run down the list of ones I am considering. For cost reasons they are all garrett turbos. Everybody else seems more expensive.

T04e - 54,57,60 trim
T04b - S,V trim
62-1

I am looking to push low boost levels to begin with, maxing at 10 psi for now. I will probably start at about 4-5psi and work up from there as I learn more. The setup will be air/air intercooled.

My thoughts are as follows on the turbos:

62-1 is a great looking map, especially in the higher rpm band. Down sides are the ighest costs, and the largest size making packaging into the car more difficult.

T04b S trim - Cheapest series of turbo, true T4 turbine. Great map in 3-5000 rpm range, 7000 rpm pushes the efficiency under 50%

T04b V trim: Also cheap. Easier to package. T4 Turbine. Efficiency peaks at 5000 rpm and stays above 65% until 7000rpm. downside is surge possible above 7psi at 3000rpm. Likely not to be completely up to pressure by then.

T04e 54 trim - good from 5-10 psi. Hybrid T3 Turbine. Easier to package. Peak efficiency is 4-5000rpm staying above 70% at 7000 rpm. down side is high rpm boost may not be available under 5psi.

T04e 57 trim - good for 5-10psi. Cheap, popular ricebox turbo so finding them is easy. small and easy to package. high rpm boost may be limited under 5psi. 60-65% efficiency at 700rpm.

T04e 60 trim - good efficiency ratings. peaks about 5000 rpm. 10psi and 3000 rpm is right on surge limit. 72-74% efficient at 7000 rpm.

If I was to choose right now I would have a tough time. Right off I would rule out the 62-1 for cost/packaging reasons. I think I would aim for a hybrid t04e with probably the 57 wheel. it limits surge, and is a good split on the 60 and the 54. Availability is great too.

my personal opinion is a 57 trim hybrid with a .63 A/R for better capacity. (vs. .48)

Ok, what are the thoughts. I am especially interested in you guys with turbo SHO engines.

Later,

Zach Leahy

 

[K-Dawg]

Holy crap. Somebody's actually going about this the right way and looking at maps.

Sorry I can't help you, but good luck.

 

[Toolman]

60-1 HIFI. Inexpensive, good for all the horsepower you will need, easy to package. In fact, I might be interested in selling you mine.

 

[pj'l_master]

60-1 HIFI. Inexpensive, good for all the horsepower you will need, easy to package. In fact, I might be interested in selling you mine.

where did you buy yours? and what do i have to do to my car before i can put that in it (are the prerequisite mods that need to be insalled)

 

[Dr. Tweak]

Uh oh... time for some turbo math!!! WOOT


All calculations are at sea level and 80*

10 psi + 14.7 = 24.7 / 14.7 = 1.68

Pressure ratio: 1.68

3.0 liters x 61.02 = 183 CID

Max RPM: 7500

Volumetric efficiency: I'll assume 90%

So...

183 x 7500 x .05 (4 stroke takes air 1/2 the time) x .90 / 1728 (inches into feet) = 357 CFM

Now the CFM under boost will be: 357 x 1.68 = 600 CFM

600 CFM x 0.074 (weight of one cubic foot of air at sea level and 80*)= 44 lbs/min

And we'll also assume that full boost will be reached by 1/2 max RPM which is around 3800 (22 lbs/min)

Here is the T04e 57 trim:



Way too small. The line runs right off the map around 38 lbs/min.

T04b S:


Again, way too small, this map only goes to 38 lbs/min.

t04 60-1:


This pic is a little screwed up for some reason, but you can still see that this is a great turbo. The lines runs right though the middle of the efficiency island and just starts to fall off at 44 lbs/min.

The T-61, T-64, and T-66 could be used too, but they would be better suited to high boost... If I were you, I would definetely go with the 60-1. Besides, Toolman said it's a good one, so what else do you need?

*edit* BTW it's $649 here: http://www.turbocalculator.com/map-t04.php?img=t04-60-1&turbo=Garrett T04 60-1

 

[K-Dawg]

Now that's what I'm talking bout.

 

[leahyz]

Dr. Tweak,

Yup you are barking up the same tree as I was. I think I used a bit more conservative numbers like 80% efficience and 7000rpm max. I was looking more in the lower boost numbers (5-7psi) since I was looking for a good starting point. I know as the pessure begins to rise, I would have had to look for a better suited turbo.

Thanks for the input. I had looked at the 60-1 as well and I had at one time settled on that (or possibly the 62-1) when I started looking for physical size information. I was a bit shocked at the size of this thing vs/ say a T3 (which I am most familiar with on SAABs). Toolman, are you running the 60-1 on your setup? How was fitting it under the hood (typical where the airbox was setup)? Maybe I am just nuts, I can't say I have been out doing measurements to see if it will fit or not. (I'm probably just paranoid... <grin>) I prbably will be getting it from turbocalculator.com. I have their software and that's what I have been mapping out all these turbos on. Great deal for 20 bucks to be able to plot right onto the map.


toolman - email me and let me know about this one you may have for sale.

Z

 

[1slickRED89]

you should atleast look at, if not consider, a divided turbine inlet. they have the t04s designation i belive. t60-1 is a good comprimise (hifi if you want 2" inlet and outlet, otherwise they are bigger), you can score a turbonetics brand one for around $850 with a divided turb. inlet ($156 extra) and water cooled center section ($56 extra) from vecco hi prof in cleveland ohio. Corey

 

[munkee]

Will a divided inlet do any good where the turbo is mounted? The exhaust pulses should be pretty well mixed by the time they reach the turbine won't they? Water cooled isn't a bad idea though.

 

[Dr. Tweak]

It's going to be up by the airbox? Hmmm... not sure on that one but I'll bet it would still help a little.

 

[SASHO91]

hey what about a garrett AR 50 M27? i happen to have one laying around......

 

[1slickRED89]

Will a divided inlet do any good where the turbo is mounted? The exhaust pulses should be pretty well mixed by the time they reach the turbine won't they? Water cooled isn't a bad idea though.

i would expect that using a divided inlet you could lower the boost threshold by a few hundred RPM (vs a regular inlet) despite the consterable distance the pipe would need to be. watercooled centersections will allow longer oil change intervals, and thats good. Corey

 

[SonicRiot]

I can't find a turbo map for the turbos I have and I don't think TurboCalculator has the map I need.

I have 2 Borg-Warner *** K27 "quickspools." They are used on 1996-1998 Porsche 993 Turbos and can be used as an upgrade on 930 Turbos. I figured they wouldn't be too bad because the Turbo engines redline at around 7000 RPM and make strong boost by 2500 RPM. I was thinking about using just one due to the lack of space. I know the turbos are capable of about a bar each (about 13+ psi), so they could provide plenty of boost.

Do I have a suitable turbo or turbos for a 3.0L block with a low-compression rebuild?

Does anyone have the map?

Thanks in advance.

 

[SonicRiot]

anyone have the map or know where I can find one?

 

[munkee]

Well, the Porsche engine is similar in size to ours, maybe a little larger. If you used both turbo's it would probably be ok, but I think using just one would be too small. Sorry, I couldn't find any maps for them. You could try contacting the company that makes the turbo or a company that sells them and get their advice.
Just remember that all turbo's will produce boost on your car. The key is to keep the turbo in a good efficiency range. The less efficient a turbo is running (from being either too small or too big) the hotter the air charge is and the more wear is placed on the turbo. You can also create boost too soon which creates driveability problems, or choke off at higher rpms because the turbo can't move enough cfm to feed the motor.

 

[wicked93gs]

you need a turbo with a lb/min flow of at least 50lbs on this engine...or twins at 25lbs each(all this calculated from engine size and cfm flow of the heads), NEVER get a turbo that drops below 65% at high RPM, your just choking the motor at that point, and depending on how much boost is where you want to look on the pressure ratio (IE a pressure ratio of 2 is 14psi, 3 is 28psi, pressure ratio is atmospheric pressure, all this is covered in Maximum Boost, by Corky Bell, I HIGHLY reccomend you get this book before designing the turbo system...wish I had on my turbo neon...it would be far better(its good now but could be better, realize "kits" are put together mainly on a low budget to make a profit, to do it right, you should design it yourself), now I have to redo it...fun fun

 

[SonicRiot]

Thanks for the advice. Never even considered getting a kit... the prices are ridiculous.

I never even thought of contacting the company. I'll talk to the guys at TurboDriven.com