Precision 6266 Vs. 6466 (Goal - 700whp)

Clean WHP

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Apr 24, 2017
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So I'm currently making a spreadsheet for my single turbo build im planning to do here in a few months. I'm trying to make it as thorough as possible and something I cant decide on is which size precision turbo between 6266 or 6466. I know I'll most likely be doing a Doc Race kit, 7.5" VRSF FMIC, BL tuning Ignition coils, Open downpipe, and other good supporting mods.

When I first do my build, I'll likely just be running 93 octane pump gas for the rest of the driving season (summer/fall) and then over next winter, Ill ramp things up for next driving season with port injection/full E85 and my goal will be 700WHP.

I don't really have a desire to much more than around 700WHP due to wanting to make the stock motor last as long as possible, but I def want to be around that 700 mark.

6266:

Pros:
-Spool
-Easier fitment in engine bay
-few hundred bucks cheaper

Cons:
-
Might be pushing it close to its limit at 700WHP (could possibly decrease lifespan)
-will need higher PSI to reach 700WHP
-(this one doesn't really matter) but I feel like a ton of people have 6266's and its kinda a cookie cutter build

6466:

Pros:
-Will hit 700WHP with ease and at less PSI than a 6266
-Depending on Tuner, 6466 can have very close to similar spool to a 6266 (so ive heard)
-For first phase of my build on 93 octane only; it will probably make a good amount more power than a 6266 (i'm guessing maybe 30-40whp)
-Won't be close to reaching the ceiling / max capability which in turn could provide a longer life of the tubo.
-6466 just sounds badass

Cons:
-possibly more lag
-few hundred bucks more
-possibly a little bit harder fitment like near the strut tower

Either turbo I go with, I will be getting ball bearing. I am leaning towards the 6466 but if the spool is significant then I could change my mind. Also I don't want to be that guy who has way bigger of a turbo then they need. Let me know what your guys opinions would be for my power goals and any other pros/cons I might not be seeing!
 
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Abacus38

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I've seen 6266 gen 2 hit 800whp on e85. Shoot Omar made 750whp with a gen 1. You'l be fine with that turbo. No need to step up to the 6466. On 93 expect around 560-600whp.
 

Twisted Tuning

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Unless his engine is built. 6466 (or similar) is the choice.

6266 needs needs about 28-31psi to make 700whp, so keep that in mind.

750whp is pushing the 6266 further than it should for any longevity
 

Torgus

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I would vote 6466 for more headroom.

If all you want is 700whp 6266 @ 28-30psi will get you there with better spool. If you really want 750-800whp then 6466 but it's a lot laggier.

I've always heard they spooled very similar. Obviously you have much more experience. Can you quantify how much slower the spool is or perhaps post an example?
 

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Sergeant
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I would vote 6466 for more headroom.



I've always heard they spooled very similar. Obviously you have much more experience. Can you quantify how much slower the spool is or perhaps post an example?

It's pretty noticeable behind the wheel. I've swapped ACF twin scroll kits between the turbos and driven the back to back. The key though is the 700whp... If you are good with that then 6266. But, if you are thinking more like 750whp then it has to be the 6466.
 
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The Banshee

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Interesting topic. I am having a doc race single built right now. I researched this for quite some time. In the end I opted for the 6266 as I am not looking for more than 650awhp.

I found some threads claiming the 6466 can spool just as fast as the 6266 with proper vanos tuning. I have not seen any proof of this and Terry’s comment leads me to believe I made the right decision with the 6266. I would really love to see a dyno overlay of both.
 
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Torgus

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Last edited:

N54QC

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Interesting topic. I am having a doc race single built right now. I researched this for quite some time. In the end I opted for the 6266 as I am not looking for more than 650awhp.

I found some threads claiming the 6466 can spool just as fast as the 6266 with proper vanos tuning. I have not seen any proof of this and Terry’s comment leads me to believe I made the right decision with the 6266. I would really love to see a dyno overlay of both.
I have heard the same that the 6466 can spool almost the same as a 6266 but can't remember where I read it. It's probably been 2 years since I was researching the topic.
 

Clean WHP

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thanks for all responses and feedback guys! I am thinking 6466 just cause of the headroom. only reason I dont really want more than 700whp is because idk how well the stock motor would hold it and if I would really be able to get that power down to the ground. But there is a small possibility way later down the road I would say f it and send it / go for more than 700whp so 6466 is a good selling point there.

about the spool - I have heard that the 6466 gen 2 ball bearing can spool basically just as well as the 6266 so im not too worried about spool. I also plan on running a motiv boost box and full custom MHD flash so depending on who the tuner is, spool could really be minimal.

Another thing I forgot to mention would be power curve. I feel like a 6266 @ 28-30PSI making 700WHP would start to loose some power around 7k RPM where as a 6466 would hold the peak power all the way out to peak RPM.

Also roughly what psi would a 6466 make 700WHP at? 26psi?
 

Clean WHP

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Apr 24, 2017
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I've seen 6266 gen 2 hit 800whp on e85. Shoot Omar made 750whp with a gen 1. You'l be fine with that turbo. No need to step up to the 6466. On 93 expect around 560-600whp.

Im expecting around 550whp on 93 with a 6266, but I think a 6466 would possible edge close towards 600whp on a safe 93 tune which is a selling point for me cause I will use pump gas initially / may from time to time with flex fuel down the road. so 93 octane power would be nice to have
 

doublespaces

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It's pretty noticeable behind the wheel. I've swapped ACF twin scroll kits between the turbos and driven the back to back. The key though is the 700whp... If you are good with that then 6266. But, if you are thinking more like 750whp then it has to be the 6466.

It's good to see this confirmed off the dyno charts.
 

Abacus38

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thanks for all responses and feedback guys! I am thinking 6466 just cause of the headroom. only reason I dont really want more than 700whp is because idk how well the stock motor would hold it and if I would really be able to get that power down to the ground. But there is a small possibility way later down the road I would say f it and send it / go for more than 700whp so 6466 is a good selling point there.

about the spool - I have heard that the 6466 gen 2 ball bearing can spool basically just as well as the 6266 so im not too worried about spool. I also plan on running a motiv boost box and full custom MHD flash so depending on who the tuner is, spool could really be minimal.

Another thing I forgot to mention would be power curve. I feel like a 6266 @ 28-30PSI making 700WHP would start to loose some power around 7k RPM where as a 6466 would hold the peak power all the way out to peak RPM.

Also roughly what psi would a 6466 make 700WHP at? 26psi?

From what I've seen 6266 and 6466 will make 700whp at the same PR on a stock motor. You won't see the 6466 shine until you get outside of the 6266 efficiency range. That means pushing it beyond 750-800whp hence why I said stay with 6266 if you only want <700whp
 
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ccbsecu

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From what I've seen 6266 and 6466 will make 700whp at the same PR on a stock motor. You won't see the 6466 shine until you get outside of the 6266 efficiency range. That means pushing it beyond 750-800whp hence why I said stay with 6266 if you only want <700whp
He’ll regret not getting the 6466....
 
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Twisted Tuning

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I'd still get the 6466 for 700whp....

Screenshot_20180411-233701.png


Don't mind the trims.