I've been talking to a shop in florida where I got my lt10 from and have to send back off to get a 4 bar map sensor put in. The guy there is constantly telling me that the turbo I have is not all that great and he would recommend something like a 72mm turbo with a huge hotside. He says everyone of the puerto ricans that are making huge power is doing it on huge turbine wheels. He mentioned that he just put together a turbo setup for someone that had a z trim wheel. I asked him how that effects spool and he said that is a non issue as he matches the correct compressor side with the right turbine wheel. He says alot of people put huge compressors on the compressor side and then a small turbine wheel on to make it spool faster but he said actually the opposite is true. He said that a smaller compressor wheel is needed (he also said something about the compressor wheel comming to a point witch helps spool up time) and the right sized turbine and with that combo it really opens up the potential of the rotary because as we all know the rotary loves to breath. Anyways sorry this isn't very technical as I'm not the best with turbo lingo but what he was saying made some sence and I was just wondering why I don't hear this much on this site?

 

Your friend is correct in many aspects. A compressor wheel needs to be matched with the proper turbine wheel. You want to keep the tip speeds of both wheels approximate wiht one another (in otherwords, close to same major wheel diameters). This is just in genreral as theres many more aspects in which to consider. Also total area of both wheels too. YES a large compressor will spool faster with a proper sized (read: large) turbine as well. Were a P-trim is more suited for 62-1, 60-1, T04E family compressors, t04B compressors and GT35 sized, anything bigger should step up in turbine as well (Q trim). YES the rule of thumb were small the minor or higher the trim turbine the quicker the spool. This is true for staying withen the realm of matching compressors. EX: a T04E 57 trim will spool up quite noticably quicker running a O-trim (same inducer or major as a P-trim, smaller exducer or turbo outlet/minor). Step it up to the larger P-trim and its spool will slow, but peak power will rise as with A/R numbers. Now if you step it up to a Q-trim, the opposite will happen. The turbine wheel is just too large and will be a spooling slug and not much top end if any will be gained because its a pretty small compressor. Q-trims really aren't suited to anythign smaller then a t66, were the major wheels diameters get close. Now on a large frame turbo, the p-trim might be too small for good response (turbine wil be much smaller then the compresor). The extra leverage from the larger paddles are needed to get those larger turbos spooling. N,O, and P trims all have the same major wheel diameter. Its there monir wheel diamter that changes, so withen those 3 turbine, the smaller exducer (N-trim) will always spool faster given all other factors remain the same (same compressor, turbine A/R etc). now the Q-trim steps it up in both major and minor diamters. SO, again its suited for larger compressors and will work better with them. Then theres R-trims and now I guess theres a Z-trim.

I hope I explained this so it makes sence lol.

~Mike...............

 

To answer your question "anyone using hotsides larger than Q trim? " yes, several are. The GT40 has a turbine very close to a Q-trim (but its a GT wheel). Theres several in here running a GT42 and GT42R, both have larger turbines then a Q-trim, then theres the GT47, GT55, and GT60. Don't know many running that big, maybe 20b guys are but there turbines are massive 82mm, 93mm, and 103mm.

~Mike..............

 

Thanks man, I was hoping to get some input from you. I'm going to get some more info to see exactly what he is talking about because the turbines he was talking about are just huge! I know most of these guys are running 13b's to so it's just some way they are able to match a 72mm compressor (give or take) with a huge turbine. I was thinking the hole time he was talking to me all the differant turbine sizes I've heard that we run and it's usually the ptrim qtrim and what the gtqrim (whatever that is).