london

ok can someone explain the difference ,i know q is bigger than p of course,but should i get a p trim or a q trim wheel for my turbo.Which wheel spools quicker and which should make more hp and by how much percen.t

RETed

Turbine section technically does not change power potential - the compressor side is more effective means of doing that.

The large turbine wheel will spool faster.



-Ted

slow wankle

don't quote me on this, but I think that the P-trim will be better for the bottom end where the Q-trim is better for top, so if you are going with a bigger turbo the P-trim would be a better choice, and with a smaller turbo, the Q-trim would be better. if you want to be sure you can call turbonetics and they will tell you. I went through the same thing when deciding my turbo. I went with the P-trim on a T-70 with a .96 A/R turbine.

--John--

$150FC

Ted, i thought the larger wheel (the q-trim in this case) would spool slower but flow more on the top end?

jspecracer7

I think you mean slower. My old turbo(turbonetics 62-1 compressor .70 a/r, P trim a/r 1.00 exhaust) would spool up right around 3500~ rpms with full boost(14 psi~) by 4000 rpms. I switched to an HKS T-45S and now I get full boost(14 psi~) by 5000 rpms. I have no measurements of the T-45S exhaust wheel, but I did a visual comparison of a P trim wheel to the exhaust wheel of the T-45S and there was definitely a large visual difference.

RETed

No, I still stand by my statement - the bigger turbine wheel will spool faster.  The bigger turbine wheel will utilize more of the exhaust gases, and this it will spool faster.  Smaller wheels (just like clipped turbine wheels) cannot utilize as much exhaust gas power.  Wheel (and shaft) weight is not as much as a factor as the wheel design itself.


-Ted

RETed

Um, you really cannot compare turbo performance between two different compressor sections.


-Ted

$150FC

So, from smallest to largest, physically, it is O trim, P trim, Q trim?

And the Q trim would spool faster? Why does everyone say that the q trim is not good for a street car, then? And an O trim is practically useless in an RX-7 (or so i thought) because it spooled too quickly and caused boost creep.

BLUE TII had an O trim in his hybrid, it spooled by 2500 rpm...you think with a Q trim it would be even faster? I can't see how that would work.

I'm thoroughly confused now.

Erdin

i alway thoght the a p trim would spin up quicker and a q trim would take longer but produce more power futher up the rev range.

Erdin

i alway thoght the a p trim would spin up quicker and a q trim would take longer but produce more power futher up the rev range and this why alot of people wouldent use them on a road going car cus most of the time they are at lower revs.

Erdin

sorry about the dubble post guys

RETed

From what I understand, the early Q-trim turbine wheels were just P-trim wheels with welded tips.  With the high rotary heat, these tips just burned off.  I've heard the Q-trim turbine wheels are now one piece and a lot more reliable.



-Ted

RacerXtreme7

iTrader: (2)

P verses Q trim turbine wheels.

The Q spooling faster then a P trim is WRONG.

T4 framed turbine trims go in the following order from small to large.

N, O, P, and Q trim. There exist an R trim also that is exclusive to either Turbonetics or Innovative (I don't remember which).

P trim is optimum for any street and road race 13b powered vehicle. Q trim is usually reserved for all out top end power and usually uses a smaller turbine A/R to gain some spool back but still will out flow the P.

The Q trim wheel is NOT a P trim with bigger paddles welded on or casted into it. It is it’s own wheel design and not only does it have a larger inducer (major diameter) but it also has a larger exducer (discharge, or what you'd see looking at the back of a turbo).

P-Trim wheel: inducer/major dia. 2.922” , exducer dia. 2.544”
Q-Trim wheel: inducer/major dia. 3.111” , exducer dia. 2.693”

Also NOTE: If anyone decides to go with the Q trim wheel this means you will have to go for the “Big Shaft” option adding hundreds of dollars to the turbo chargers cost. But in most instances people electing to go with the Q trim option will be running LARGE compressors which puts the turbo charger in the “big Shaft” category.

TRUE..... a larger turbine inducer (major diameter) will help quicken spool up due to having more leverage on the shaft ( low energy diesels use large turbine blades to spin their compressors), BUT the Q trim has a larger exducer as well, so its a slower spooling turbine. Turbines work on pressure differential from the inlet (exhaust port to the turbine) and the turbo's discharge port (were your down pipe bolts or clamps). A smaller exducer will yield more restriction and a higher-pressure differential thus quicker spool (same reason going from restrictive stock exhaust to a hi flow unit quickens spool, you altered the pressure differential), but less top end due to backpressure. The P trim is good for 500 wrhp, so don't think of it as a "restriction" but a great compromise of spool and ultimate power.

The newer GT series turbines (GTQ) are GREAT. The T4 sized P-trim equivalent spools like a P trim but flows like a q trim.

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

RacerXtreme7

iTrader: (2)

I just read through my own post and don't want to confuse some people being overly technical so I sumed it up simpler.

The smaller trim the quicker spool.............O being quickest spooler and Q being slowest. (or R trim being the slowest, remeber, R trim isn't widely used, its not a common Garrett part but is exclusive to an other manufacturer)

The smaller turbine trim the more restriction (back pressure) and the less ultimate power being made. Again, o being less power then the big Q (or R trim).

So the p trim will spool faster then the q, the q making more power on top.

The GTQ being the ultimate if you have the money for the new GT series turbos, flow like a Q and spool like a P.

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

$150FC

I want spool like an O and flow like a Q
Ultimate turbo. Maybe in 5 or 10 more years...

Thanks for clarifying. I am no longer confused.

JUN S14

Did you mean that the T4 sized Q-trim spools like a P trim but flows like a q trim? ala the GTQ? Because I haven't heard of a GT version of the P trim... but it would be sweet if there were.

$150FC

sounds like six to one, half dozen to another.

Oh, i see what you are saying. Kinda what I said earlier - spool like an O, flow like a P. Yeah, i could dig boost at 2500rpm and power at 8000.

SPOautos

I think what RETed was trying to get at is all things being equal the Q would spool faster. In other words normally you have a smaller compressor wheel on the smaller turbine wheel so there is less weight on the other end of the shaft. If you were to keep that smaller compressor side and put a larger turbine wheel on the back of it (like a Q trim) it would spool faster cause it has more leverage. Course I dont know if thats possible cause I dont think a Q will fit in the smaller housings.

I think the main reason a Q trim is normally more laggy isnt due so much to the turbine wheel side but rather the much larger compressor wheel its having to turn

STEPHEN