Why all the "big" turbo kits @ low boost

[mrk1]

Originally Posted by Coheed

The ns111 wheel has more power potential and no hit to response, transient or boost onset. It would be much better suited to use the .86 housing on the GTX turbos, because they flow more air than the standard versions. In all my testing (take with grain of salt) the .86 housing was better all around for the t2 flanged turbos utilizing the ns111 wheel. I'd actually take the ns111 over the T30 because it is more efficient. It can actually flow very similar to the T30 turbine in the .63 housing, perhaps a bit more. It's a great wheel with low inertia and great response. The only combo I don't much care for is the 71mm GT30r compressor being used with it. The turbine flows well but the torque moment isn't large enough to drive the compressor that size efficiently.

Mind you, all my testing has been done at higher elevations. This has an impact on the turbos performance in a lot of different ways, so sea level results can vary to my personal experiences. Likewise, I've tested a lot of the housings for several of the garrett turbos and the .86/.82 housings have always out-performed the smaller counterparts without any cons to how the power is delivered. The smaller housings do seem to spool a bit softer and give a more linear feel to how the boost is felt. The larger housings can have a rather abrupt boost onset which could be a bit harder to control, but I love the feeling!

I tested the .63/.82/1.06 housing on a GT3076r back to back and the larger housing did make more power. The 1.06 had iffy transient response, but really just felt like a non-bb turbo. The compressor never surged with this housing though, unlike the others. I bet the 1.06 would work decently well with the non-ported shroud compressor cover. Should help improve the efficiency of the compressor. I don't have the time or resources to do this kind of testing anymore.

Interesting, luckily swapping turbine housings is cheap enough that its completely viable to try some options. I plan too.

[jamesm]

Originally Posted by diss7

Wat.



James, don't think you are suddenly knowledgable about everything, because you have starting tuning cars; and that everyone else is inexperienced.
All the cars and turbos I have quoted, I owned, and tracked them. Granted I didn't tune them.

If there is no lag difference between your gtx2867r and a gtx3076r, I blame the tune, or the car. Show me a dyno where one turbo has been taken off and replaced with the other and there is no lag difference. You can see on the PTUNING kit where the max boost is reached. Its around 500 - 1000rpm later than a gtx28, depending on whos dyno you are comparing it to.

I'm not saying that a gtx28 turbo will make the same power as a gtx30. I'm saying that using a gtx30/35 for a hp target that a gtx28 can easily reach is not always better.

I spent the day at the track yesterday driving my ae86 drift car. 2000cc, 400whp. Spins up 4th gear while spooling. It just makes me laugh when I'm out there driving that, that there are people here talking about having more than that in a street car.
This is pump gas. 10:1 static comp.

Oh, and its a t28 frame turbo. (Tomei M8270) Not even BB.




Granted, I am considering replacing that turbo with a gtx3067r. I think it's well suited to what I want from the motor. I'll stick around the 400whp mark, but it should spool sooner (because BB and billet), and run cooler. But, take note, I'm at the 400whp mark, making the call to go from t28 frame to t30 frame. I wouldn't be making that call at 300whp. gtx28 for 300whp all day erry day.

Look, we all have different goals, and I'm doing is putting forward a counter arguement; as I dont like seeing a heavily one sided thread, which will then lead others to believe its fact.

I didn't say I was knowledgable about everything, I said I was speaking from experience regarding these 3 turbos we are discussing here and now, having tuned and ridden along in cars equipped with all three of them. I also didn't say that there was no difference in spool, I said that the difference wasn't as perceptible as you would expect. It just isn't as big of a difference as even I expected, that is all.

My point is that if you were to experience all three, you'd have a more sound basis on which to make a judgement, and would likely find the difference to be far less than expected, as I did. I wouldn't have believed it either if I didn't experience it for myself.

Sorry if you think my post came off as a bit of a **** (it did, I agree), but I really think you should take a ride before casting judgement based on experience with other cars or from applying what I agree is common knowledge on the subject.

[diss7]

My opinion on spool is its more noticeable on a daily commute. I don't doubt on ride alongs up and down the highway, that a bigger turbo doesnt feel much difference. Ditto on the track.

For me, spool difference of even a few hundred rpm can make the difference of whether the turbo is in boost when I come out of a corner, or whether I have to wait for it; which then inturn governs whether I'm happy with the entire setup or not. I want my turbo to hit like a lightswitch at 3300-3500rpm. I'll either use the accelerator to modulate this if I want traction, or I'll keep it buried and enjoy the fact I dont have to clutch kick my car anymore to hang it out.

[jamesm]

Originally Posted by diss7

My opinion on spool is its more noticeable on a daily commute. I don't doubt on ride alongs up and down the highway, that a bigger turbo doesnt feel much difference. Ditto on the track.

For me, spool difference of even a few hundred rpm can make the difference of whether the turbo is in boost when I come out of a corner, or whether I have to wait for it; which then inturn governs whether I'm happy with the entire setup or not. I want my turbo to hit like a lightswitch at 3300-3500rpm. I'll either use the accelerator to modulate this if I want traction, or I'll keep it buried and enjoy the fact I dont have to clutch kick my car anymore to hang it out.

Different strokes for different folks. To be honest though it was the response around town that impressed me the most about the bigger ones. Wide open pulls from low rpm in 3rd or 4th gear is where the difference is most noticeable, IMHO.

[diss7]

Yea for sure. I'm just not planning on driving my car like that. Its a street car. Not a track car (have one of those) not a highway car (dont have enough of them here)

I drive my street car on tight twisting roads, where spool and response make or break the experience. There are VERY few spots you even get into 4th gear.

http://goo.gl/maps/P8aWv

I actually wont be using anywhere near 300whp on these roads, for most of the time. My gt86 NA keeps up with STIs now, on all but the most open sections.

[AVOturboworld]

Originally Posted by Ironsquid

Shouldnt you be fixing your breather tank orders? I cant in good faith accept your advice when you arent shipping the correct parts.

And you threw up a dynograph without saying what turbo was used and I assume thats an 86.

I apologize for that, who did you contact about your issue with the breather tank? I'll see what can be done on that one.

Turbo used was a "small" 18G size turbo, the one that ships in our kit, and seems to be the reference point for small in this forum. Never mind that we'd rate it on the large side for a 2.0-liter.

Everybody has different power and drive-ability goals, and I of all people respect that greatly. There is a balance to everything, and finding the right one for everybody is impossible.

But some of the claims are a bit outrageous, especially the one where a small turbo will break things faster than a large one. There is a whole lot of automotive manufacturers with billion dollar budgets who are getting it all wrong then - hell, I owned one of those mistakes, a 2.0-liter twinscroll legacy who's peak torque was reached at 2400rpm out of the factory. They've since lowered it to 2000rpm. Did a lot of time attacks and circuit racing in that particular car. Only thing I broke was the front drift, and that was from doing a 360 around a cone at the end of a hill climb.

Did a small turbo setup on some cars cause breakage issues? Yes. Did a large turbo setup on some cars cause breakage issues? Again, yes. Does it apply to this car with these setups? There is no definitive answer, the car is new, and the highest mileage cars with FI are still only in the 20k~30k range. If we are to base everything off of what has happened with other vehicles, then we'd all still be running 5~6psi max, because that's also all that boosted Subaru N/A motors traditionally could take (12+ years of experience doing that!).

[FAER]

Originally Posted by AVOturboworld

...

But some of the claims are a bit outrageous, especially the one where a small turbo will break things faster than a large one. There is a whole lot of automotive manufacturers with billion dollar budgets who are getting it all wrong then - hell, I owned one of those mistakes, a 2.0-liter twinscroll legacy who's peak torque was reached at 2400rpm out of the factory. They've since lowered it to 2000rpm. Did a lot of time attacks and circuit racing in that particular car. Only thing I broke was the front drift, and that was from doing a 360 around a cone at the end of a hill climb.
....

to counter this argument is simple...

The motors to which you are referring were designed for that torque... The fa20di motor is not. It's designed with that sub 200ft lbs of torque..

big turbos ease the torque on making it "somewhat" safer.

not saying big turbos are "Safe" by any means.

think of it as someone dropping 300lbs in your lap or setting 300lbs in your lap...

[AVOturboworld]

Originally Posted by FAER

to counter this argument is simple...

The motors to which you are referring were designed for that torque... The fa20di motor is not. It's designed with that sub 200ft lbs of torque..

big turbos ease the torque on making it "somewhat" safer.

not saying big turbos are "Safe" by any means.

think of it as someone dropping 300lbs in your lap or setting 300lbs in your lap...

But those Legacy motors that made peak at 2400 rpm were not designed for torque - it's the same base EJ207 as been used in the STI twinscroll... that makes it's peak torque at 3600rpm. Difference was in the turbocharger setup itself and the tune. Just like the bigger turbo vs. smaller turbo argument here, they swapped low end torque and response (VF38) for top end performance (VF36/37).

And my argument was, if a bigger turbo is "inherently" safer because of "gradual" torque (and I'm still not sure how jumping 200ft/lbs over a 1000rpm range is gradual), then why doesn't the manufacturers clue in to that?

The easy answer to that is that, for them and their customers, it is about daily driver response, gas mileage, and area under the curve. And given their budgets, they can and do design and tune for a turbo that will work through closed and open loop with reliability and smoothness.

The new Legacy motor that made peak at 2000rpm? A variant of the FA20, the turbo version.

[SmsAlSuwaidi]

Originally Posted by AVOturboworld

But those Legacy motors that made peak at 2400 rpm were not designed for torque - it's the same base EJ207 as been used in the STI twinscroll... that makes it's peak torque at 3600rpm. Difference was in the turbocharger setup itself and the tune. Just like the bigger turbo vs. smaller turbo argument here, they swapped low end torque and response (VF38) for top end performance (VF36/37).

And my argument was, if a bigger turbo is "inherently" safer because of "gradual" torque (and I'm still not sure how jumping 200ft/lbs over a 1000rpm range is gradual), then why doesn't the manufacturers clue in to that?

The easy answer to that is that, for them and their customers, it is about daily driver response, gas mileage, and area under the curve. And given their budgets, they can and do design and tune for a turbo that will work through closed and open loop with reliability and smoothness.

The new Legacy motor that made peak at 2000rpm? A variant of the FA20, the turbo version.

What about the ability of these small turbos to hold to redline, even in the graph you guys posted above it tapers off after 7000 ?


Sent from my IBrick

[cdrazic93]

Listen, guys guys guys. guys. If you want boost early, get a supercharger. If you want more power, get a turbocharger. But wait, why not both?

http://www.ft86club.com/forums/showt...t=44768&page=1

/thread

Lol jk

[mrk1]

just going to leave this here,

[Coheed]

Originally Posted by mrk1

just going to leave this here,

GTX3076r correct?

I wonder if the GTX3576r would need the ported shroud housing? the 76mm typically comes with the ported shroud since it was mated to a small turbine. The larger turbine should allow you to get rid of the larger housing which could actually free up some space.

[mrk1]

Originally Posted by Coheed

GTX3076r correct?

I wonder if the GTX3576r would need the ported shroud housing? the 76mm typically comes with the ported shroud since it was mated to a small turbine. The larger turbine should allow you to get rid of the larger housing which could actually free up some space.

GTX3576r, its does have the ported housing. Comp housing is the same frame as the 3076, large reason why I choose this over the 82. My turbo sits lower then say the FBM kits so I was concerned about clearances.

[diss7]

I've gone turncoat and changed to a gtx3071r.

I've plotted it at where I think a pump tune will be. Basically 10psi resulting in 320whp at 7500rpm.

It's good to also see that should my car be able to spool the turbo freakishly earlier at 3000rpm, that it's still inside surge. A 76mm wheel moves this surge line to the right, risking compressor surge. So this gives me faith in using the 71mm wheel, in opting for the t04b cover instead of the t04e. That means I have two things working in my favour over a gtx3076r in terms of spool, a smaller comp wheel, and a regular non anti surge comp cover.

I've also opted for the 0.63 ex housing.

All this, combined with the smaller runners of the jdl manifold gives me a lot of hope for a great street kit.

3000rpm and 7500rpm plotted @ 10psi