Turbo Trend..
 

Has anyone else noticed the 57 trim, 60 trim, and gt3076 R are making more power to redline than the smaller turbos..

No i don't mean the obvious ooo bigger turbo more power.. For instance the gtx2876r doesn't seem to be able to breath on the top end and reach that 350hp goal everyone claims it has..

people were saying 300whp is all your going to get because of compression, yet the big three turbos above all cleared it by 30 or more whp with ease..

I dunno i think the mind set of the disco potato being most appropriately sized may be a bit off.

thoughts...

I think the gtx28r turbos are hard hitters, then die off.. good for the street.. although I'm sure the hot side is playing a role here too. My friend has an evo x with a gtx30r and the thing spools beautifully, I would just skip the gtx28r and go a little bigger to future proof the car a little bit

Is this thread a wind-up?

I disagree. It's obvious that a bigger turbo will make more power at the same boost (and consequently, on the same fuel). 350whp on pump may or may not be doable on 93, but people have put down 450+ on 28r's. it didn't run out of air, it just required more boost than can be run on pump gas. I think that is to be expected.

The 30r might make a bit more power on pump gas, but it's at the cost of spool, there is no way around that. The t3/t4s aren't really a comparison as anyone looking to buy a gt/x turbo probably isn't shopping it next to an oil cooled, journal bearing turbo. They perform great, but they're not exactly state of the art. That said I think they represent the best value hp/$ available today.

So yeah, different turbos for different purposes. Didn't we all know this already?

This^^^^

he isnt speaking about power/power i think he is speaking directly at the dyno charts that show the 28s nose dive above 6800rpms that isnt going to change. fact is the turbine wheels are slow small they cant carry power that high. i dint chooose to package the t3t4 for cost saving i chose not to choke my more up top plain and simple. the 28s should never use a anyAR smaller than .82/.84 on this motor. its to efficient and will carry power better if you arent restricting exhaust flow. one of you 28 owners should do a back pressure test to. everyone has theories but i just rely on results. ive tested enough turbos over the years to know that the gtx28 & 30 are fine but i would never use the 35. precision is great but only by application. considering the gtx series uses the same old ass turbine wheels i was using in 2002 doesnt sell me on their dominance. if you guys would realize that the overall surface area of the gtx is what provides the additional air flow because the boss for the shaft is now smaller since the wheel weight is lower and the shaft doesnt have to be as thick to support the wheel.

last month nobody thought you could road race with a 60 trim obviously Element Tuning ended that theory. its easy to see where each kit spools, just look at where the tq curves starts to flatline and youll be able to see this on any dyno chart. every turbo has its purpose but i dont think the 28s belong on this motor i would stick with the t3t4 or the gt30. we have a few more tests to do over the next couple months to give you guys more options to consider.

I think a lot of knowledgable people would argue against the point that a gtx28r doesn't belong on a 2.0l engine. If you think that, who do you offer them?

I don't think he is saying a GTX28 doesn't belong on a 2.0L... i think he is saying OUR 2.0L

We aren't driving SR20DET's these motors are considerable different (obviously).

Looking at graph after graph i think Tony hit it right on the head... The GTX's seem to die above 6800rpm. But as stated earlier different turbos for different people. Me, I don't mind the slow spool too much, it keeps me out of boost when i'm cruising (unlike my spool happy SRT4 with part throttle boost issues).

I look at it like this;

When i want power, i want big power to redline, power dropping off at 6800 rpm is like dropping your redline because you got too small of a turbo. If the turbo can't breathe at the top of your rpm range then i think your looking at a sizing issue.

GTX's are "nice" and all but they seem more like a mid range turbo, and we all know when you're wanting the whp your stomping your foot to redline (or close to it).

Different turbos for different people i guess..

no, none of that makes any sense at all. a turbo that pushes 48lb/min of air doesn't run out at 7,5000rpm on a 2.0l engine. it's math. it's a false argument, it just doesn't happen.

I could be wrong, but how much air it "can" move doesnt matter when your exhuast housing reaches a point of restriction. Just my thoughts.

The easy way to see this would be to run a car with a 28 then a 30. Would be interesting to see the differences in power/spool on 93.

i agree it shouldn't "run out" at 7,500 rpm ... but check the dyno graphs all over the forums, the power falls off even sooner than 7,500..

Sometimes real world physics trumps theoretical math :/

I don't know why, i'm not going to speculate with any amount of accuracy why but the graphs don't lie.

(bro science guess is parasitic loss through thermal dynamics, after all we are 12.5:1 compression and trying to boost in excess of 10psi [e85] or just under 10 [93]. Sorry I but a lowly internet know it all :P)

So which turbo are you going with @FAER? I'm with you. I want to be off boost for DD but when I step on it I want big pawr! Even racing, it seems the 60 trim will work just fine.

It will never really make sense to those who haven't been tuning and building boxer engines for years like us. The way the exhaust pulses are, it just requires/demands more exhaust flow compared to an inline 4. It just doesn't make sense on paper, never will, but years ago we tested .63 30R and 35R turbochargers, and then swapped to .82 housings and picked up 50hp with little penalty in lag (penalty in transient boost response however).

If you compare the turbo/hp from a boxer motor to an inline 4 like a Honda or Mitsubishi you will see the trend we've been dealing with for years building boxer motors to put out 700+ hp.

We could put together a 700+ hp FA20 no problem it will just require $12k in driveline parts :) and I'm not ready to pioneer that. Ha ha.

With all that said the smaller turbochargers have their place. We don't drive dyno plots we drive our cars and for some on early and hard provides enjoyment and suits their style. For others like me on a little later but longer with more HP is better.