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-   -   Best Turbo for High Altitude? (http://legacygt.com/forums/showthread.php?t=183665)

Aquaflight 04-10-2012 10:34 PM

Best Turbo for High Altitude?
 
I drive primarily at about 9,000-10,000 feet above sea level. I am looking for a replacement turbo for the VF46 ('09 LGT 5EAT) that spools quicker but doesn't run out of power too quickly.

What is the fastest spooling turbo?

What is the fastest spooling turbo with the best high end power?

Would the AVO 380 or BNR 16g be good options?

Thank you,
Aquaflight

Edit: The altitude basically reduces the air pressure by 30%. My LGT has very little power under 3000 RPM.

underground000 04-10-2012 10:43 PM

running out of power is because the turbo is too small

my research comes to 16g spools like oem, holds a bit more power but still dies up top

I'm going to go with a 18g but boost threshold is a bit later around 3400rpms, but better on top end

20g is just too big boost threshold is around 3600rpms, but does not die off at high rpms

question is where is most of your driving done at (rpm wise?) you cant have both fast spool and top end unless you go e85

Aquaflight 04-10-2012 10:47 PM

I do a lot of driving at low RPMs in very cold weather. I really miss the low RPM torque. I am fairly content with the top end power but I am not content with the low RPM torque.

Aquaflight

Cyclozene 04-10-2012 11:36 PM

You may not even need a turbo. Just a good tune imo.
Check out the hta68. It's a load of fun!

—Pirated Tapatalk app

Aquaflight 04-10-2012 11:56 PM

How does the HTA68 compare to the VF46 and 16G?

Aquaflight

scoobyscoodle 04-11-2012 12:50 AM

An hta68 on e85 will knock your socks off at altitude. Quick spool, lots of power all the way up and as much torque as you can use. Is e85 available?

Aquaflight 04-11-2012 01:37 AM

Nice! Do you think it spools as quick or quicker than the VF46?

Unfortunately, E85 is fairly difficult to come by at the moment. I would probably need to drive 1.5 hours round trip to get it.

Aquaflight

rtbrjason 04-11-2012 05:52 AM

I think you should be considering a vf52 with a tune considering the type of driving you're doing. I haven't seen any other turbos making that much torque down in the low rpms. Legend has an insane amount of data compiled on that turbo as well if you want to see what it does. He isn't quite that high up but he is over 5k feet.

RabidWombat 04-11-2012 11:35 AM

Your best bet is probably a tuned VF46 or 16G. Maybe even a smaller WRX turbo (TD06?), although that's definitely uncharted territory.

Smaller turbo will give you better boost at low RPM, but you lose power near the redline. A new downpipe and tune could probably get you a little more low-end torque which would help.

Aquaflight 04-11-2012 06:42 PM

I currently have Stage II mods (TMIC + 2 Cat DP)

When I floor the accelerator at a stop the car slowly and gently begins moving and then all of a sudden at around 3000-3500 RPM the car has a LOT of power. I get very good high RPM power but the low RPM is pretty pitiful.

Would a 16G have a smoother increase in boost which would give more power at lower RPMs?

Aquaflight

LGT For ME 04-11-2012 06:48 PM

I havent seen any turbos that spool faster than oem turbos w/ a tune. My v52 on e85 spools a few hundred rpm slower than the v40, but when in boost its definetely more powerful. The spool may just be what it is. Our cars arent like the direct inj cars that hit full boost at like 2k rpms

ChefRacer 04-11-2012 07:10 PM

Sounds like a small turbo with ball bearings is what you are looking for the blouch 0.5r dominator ball bearing turbo would most likely suit your needs well, but it is an STI style turbo, so you would need either a FMIC which would lose you a bit of spool, or a custom TMIC to be able to utilize it. If you contact blouch about it, they might be able to make it with an LGT style housing so you can retain your tmic.

Borg Warner is supposed to be making some extremely fast spooling turbos for our cars with dual ceramic ball bearings and a titanium wheel as well. There are a couple of catches though, due to the design of the turbo, you would need to also purchase their dp and exhaust manifold b/c these turbos wont hook up to yours. Also as far as I've heard people have ordered these turbos a year ago and nobody has gotten one yet. I might be wrong about that but I havent checked on those setups in about a month.

GL with your situation.

p.s. Have you considered buying a couple of drums of e85 to keep in your yard, Ive heard that it runs great at altitude.

Aquaflight 04-11-2012 08:09 PM

1 Attachment(s)
Thanks for the info ChefRacer. Regarding e85 I worry a bit about the cold weather here. There are usually a few weeks per year when the temperature is around -20F to -30F.

I attached a graph (arbitrary values) of what my current torque feels like compared with how I would like it to feel.

In short, I don't mind if the turbo hits peak boost a little later just as long as the lower RPM curve is bumped up a little.

Aquaflight

ChefRacer 04-11-2012 08:51 PM

How much money are you willing to spend on this endeavor?

Aquaflight 04-11-2012 09:26 PM

Honestly, as little as possible. I would be willing to put a few thousand into it if the car would have a much smoother powerband. If the price gets much more above 5-6K, I think I would just invest in a different vehicle (Audi S4?).

Aquaflight


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