Turbo sizing, are my manual calculations right?

[Ludachris]

And there is some good content in this thread if you look though it. I mean, did you know all that stuff about boostest before I posted it above? A couple things in there I learned by just being pushed to dig for it. I don't see it as a bad thing. Good luck finding another complication post about boostest on this forum tbh. If this thread wasn't reopened, that content wouldn't exist.

The only reason it's open again is to see if we can get some more good information posted. Hopefully some will be able to see past the "sealioning" and patronizing tones used to try and make points to see that info. Unfortunately, confrontational attitudes tend to grab more of the attention than the actual information.

We have some well respected members of the community who could jump in and offer some good insights, but they might not care to spend too much of their time posting when it's devolving into shit talking. Right @twicks69?

 

[roadtrip_69]

This is an old post at this point, but I found it entertaining. And I just so happened to just install the

DSM 6851S aka 68HTA V3​

Coming from a "ebay" 20g that flows 44 lb/min (which lasted nearly 5 years fwiw, had some shaft play though when i was repairing a leaky coolant line going to it) I have logged over 400 WHP on it many times with minimal to no knock. Hit over 450WHP as well but that included a lot of knock and a lot of out of efficiency boost (30+ psi)(Was not planned the boost controller popped off, allowing unlimited boost). It has the 7cm exhaust housing.

I do have meth injection though to keep things together as well as a fully built bottom end and Mishimoto FMIC, straight through 3 inch exhaust , w/FP Race Manifold, 340 LPH fuel pump.

All that being said I decided on going with the 68HTA V3 as my replacement as it was a little cheaper than the Green and Red (and I didn't want to spend thousands on figuring out how to match up a non factory fit turbo) And I read that it flowed 51 lbs./min which logically should allow for 70 more WHP potential (44 lbs. min vs 51 lbs./min) without exceeding the efficiency range. And not needing to necessarily upgrade injectors (though i know i should if I max it out as it would max out the injectors as well)

My goal being remaining street able, having boost come up when its not just being wrang out to red line, as I don't plan on dragging it at a track. But wanted to take a little more advantage of having a fully built bottom end, as I feel like the 20g wasn't really pushing it. And get to (425-450WHP ) aka 500BHP reliably. 500WHP if i get new injectors or decide to run e85 (which then would REALLY require new injectors)

Now all that being said, I haven't got much behind the wheel time, and I'm still dialing in what boost to run, to get the most out of it. Without knocking on 93 and Meth injection. Probably will have to retune at some point as well (I use ecuflash). But what I have noticed is it starts kicking in just about the same spot as the 20g does/did. 3k gets you started, by 4k you are hitting over 20, and by 4300-4500 you are at whatever max you have set. So far thats around 25 PSI in my case, with no knock. Might push it to 30 just to see if it can handle it. As I can't find a flow map/chart anywhere and I even asked FP to send me one, they stated they never made one, but did confirm it flows 51(But at what psi/rpm etc.?), which i guess it 4 lbs. more than the v1/v2. So comparing the v1/v2 vs the v3 aren't apples to apples

So if anyone is interested in how it actually runs in real life let me know and I'll update as I play around with it more.

 

[Canadian_CD9A]

Oh god not this thread again..

I’ve been waiting for a 6851S dyno on pump gas for a couple years now, and I’ll likely buy one if someone shows good results. In theory it should make the same peak numbers as the v2 68HTA, which has the same compressor wheel. The v1 HTA68 had a slightly smaller compressor inducer at 49mm vs 51.2mm, which accounted for the difference in air flow potential (‘underrated’ 47 vs 51), and had the slightly restrictive TD05H turbine. Both of these factors led to the overall lower power figures they put down compared to the v2, but the v2 was a lag monster due to the larger turbine. The v3 is what the v2 HTA68 should’ve been all along. I’d like to see what you get out of it.

 

[TerminalTalon]

I have a 68HTA that I’m going to see how far I can push it. As efficient as possible because I’ve been told it will never see 500whp with an auto or break the record. I’m fine with either to make a point so we will see. I’ll say full weight but I’d get rid of rotational weight before gutting it.