Will a 6768 get me to 600whp?
 

Or will I have to go to the 7168-7175???

I'm talking about the new 6768 billet from Precision...

Any input is appreciated.

Chris

i have a precision 6776e and made 330whp(mustang dyno) at 14psi. im pretty confident i could easily break the 400's with more boost but have no need to. I would def bump up to a much bigger turbo if your shooting for 600

Yeah, I see your point but the 6776 is a cast wheel turbo.

The new 6768 has the billet wheel and according to the CFM numbers should flow enough for 600whp on a rotary but I know that "should" and "does" are different things so I am looking for some input from people that have used it or have experience with it. 67mm just seems so small to get you to 600whp...but Im kind of old school of thought...

Chris

I wanted to clarify that I am not necessarily going to shoot right up to 600whp, probably more in the low 500whp range. That is why I don't want to go with something huge that will kill my low/mid range. I just want to know its there if I want it.

Chris

I was speaking to a friend of mine who just purchased one for his supra and he said its rated for 950hp. If that is true, then it should be more than capable for 600. I have the s366 and it's on the edge of 600hp and its rated for around 800. Hopefully one of the more knowledgeable guys on the forum will chime in soon enough.

no limit has it rated for 800hp.. so the numbers are all over the place... Nolimit normally takes straight from the precision xcel sheet. I checked precision and they dont have it up there yet, however when looking at the turbos, a 6780 is rated at 750 so I'm not sure what to say about the 6768 now

Here are the links:

http://www.nolimitmotorsport.com/precision-turbo/hp-tech-turbos.html

and

http://www.precisionturbo.net/small-frame-turbochargers.php

hope this helps.. until someone actually dyno one, it might be hard to say. Back from when I use to run precision, I was always familiar with anything in the 71 range being capable of 900+

Don't forget that there is a version of the 6768 that is not billet, but instead a normal cast wheel. Turbo HP ratings are usually based on the compressor wheel's ability to move X amount of air...I'm thinking the low numbers you found are of the non-billet version.

Everything I have found points towards 900whp plus from the 6768 (on a piston of course...)

Does anyone have this turbo installed?

Chris

You'll be well into the 600's with the 6768 IF it's rated 900whp on a piston engine...

For comparison, when I talked to Precision they rated a 6765 at 90lbs/min.

The 6768 is rated at the same because its the same compressor...

At this point I am between the 7168 and the 6768...I want the smallest turbo I can break 600whp with...

C

in terms of nominal dimensions, 6768 = T04R/T04Z with Q trim turbine wheel as opposed to P trim (which would be a 6765). Now this has the more efficient compressor wheel but we don't know how much more efficient because we don't have compressor maps. All we have are regular old T04R/T04Z maps.

Mid 500s have been achieved maxing out an oldschool T04R (J-Rat did it on his s5 engine at around 25psi I think). I think a 6768 could do 600 but you would probably need 25-30psi.

It will behave almost the exact same as a cast 67mm unit until you get into the higher PR's, like 25+ psi. That's why I got rid of mine, as with the right porting and turbo, I felt I should make a tad more than 600 if I was gonna push it to 30psi.

They work very well on Evo's and other platforms that need the boost to make power, because that's what these were designed to do. I'm no engineer, but I would guess that this is due to the fact that since the extra surface area gained from billets is in the center of the compressor wheel, and I assume the majority of the volume of air being drawn through a compressor gets distributed towards the outer edges of the compressor wheel, until the demand increases to the point of making use of that extra fin area in the middle, it doesn't do much. Kind of like path of least resistance and centripetal force or something.

Oh, and when I spoke to Precision, they said that it would push nearly 100lbs/min of air, but who knows if they just pulled that number out of their ass, and at what pressure ratio. *Sigh* I guess I do agree with Arghx about these after all... :)

Hmmm...I see. The number I got from precision was low 90's for flow on the 6768.

I did find a REW on you tube that made 535 at 20psi on the old PT67h with a cast compressor wheel and a 65mm turbine... why would the 6768 not reach 600 at 25psi makes no sense to me...I'm guessing I will look into the 7175 some more and see what the numbers for that is...

Only issue is PT does not offer the Full V-band housings on the 75mm wheel yet and I was hoping I could go with that....Lets see where this takes me...

Does anyone have a 6768 installed that can chime in?

Chris

Silly question, but why do you *need* 600whp?

I'm planning (hoping) for mid/high 400's at about 18-20psi with my 6265 and can't imagine really wanting or needing anything more for driving on public roads.

Its pretty simple; have certain personal goals. I have been at 520whp before and don't want less. Why do some people want 800whp? Idk, it depends on what each of them wants to do and they get it. I dont necessarily want to go to 600whp+ out of the bat but I want the possibility of it even if I run the car in the 550whp range most of the time. This is not my daily driver, I do intend to bring it to the track.

Also, my car is not an FD, its an RX-8 which is heavier (3000lb) with similar weight distribution and therefore puts lots of the power down because of this, 400whp wont break the tires loose as it does on an FD so 600whp is like an FD with 500 which is not an absurd number.

Chris

I don't know... you should still have no prob breaking the tires loose with 400. What are you using the car for? road race? drag?

I didn't say it doesn't break the tires loose, I said not like an FD. Its simple, the car is heavier so to go x speed in x time takes more power compared to a 7. Regardless, that is not the point. I am asking for input on whether X turbo can supply enough air to allow X hp level to be reached, what my reasons are or what I am going to do with it is of no relevance...

Chris

600whp is possible with the 6768, Im positive its possible with a 6765. When I used the 6765 and saw the results other people were having, I knew the flow rate was ~93-95lb/min.

The 6768 should definitely be paired with a divided turbine housing for best performance.

Completely agree with this. If you want to drive it off a cliff its your car, your business. The topic is covering a turbo

Thanks for getting back on the topic ST.

What about other turbos in this size range, BW 66mm etc, will these make 600whp as well or is the Precision the only turbo this size that will flow enough?

:icon_tup:

The S366 might manage it, but it must be properly setup. However, it would be at the ragged edge. The custom S400SX 66mm uses an 88lb/min compressor and that would do the trick. Their new 9180 would also be enough.

Also check out Forced Performance new turbo, the GT3794R.

you will make 600 easy dude i make 535 on a non billet 6765 on 20psi now i have the same turbo but billet so 600hp is easy to get AT THE WHEELS

Haha...I was talking about your car before...I knew I had seen ti somewhere.

Nice numbers btw...:)

Chris

Chris, what compressor and turbine housings are you looking at for the 6765?

I was looking at a 6768 not a 6765 and I was going to go with a 1.00ish housing on the back and the large ported housing on the front.

Why?

Thanks.

Chris