deeman101

iTrader: (34)

Thats what I got out of the motoIQ article and 240z's results. The 3076r is just a mistmatched turbo. Although if the 3576 didn't exist no one would have argued with the results.

YogSaahoth

iTrader: (9)

240 made it clear this was not a true back to back test, so its impossible for any of us to claim the 3576 out-spools the 3076. These results basically re-confirm the reason why the 30r, in general, has been obsolete on our cars for many years now. With minimal difference in lag, you can bolt up a proper 35r variant and have similar turbo behavior with much more peak power. At the end of the day tho, the results are still impressive...this 35r reaches about 30psi at 4200 in 3rd gear.

I've always liked the idea of a 30r, but its had a hard time finding a place on our cars. There always seems to be a 35r out there that will spool up almost as quick but make gobs more power in the top. I think either of these turbos would make a great pair with a 2.3 or 2.4L. The extra motor would prob get the peak boost threshold below the 4000 mark and peak power above the 500hp mark, which seems to be a common goal for many evo owners.

RSMike

iTrader: (1)

tell that to DB that made 600/600 on his mustang dyno with a HTA3076

deeman101

iTrader: (34)

The gtx wheel is actually a bigger wheel than the hta wheel. The hta3076r is a better matched turbo. Not questioning DB's results either.

RSMike

iTrader: (1)

bigger by how much? 2%?

MrLith

I replied to your last post but it seems to not have gone through.

Anyway - compared to the HTA the GTX3076R has a 5% bigger inducer, and its exducer is only 1% larger if you don't count the extended tips - but 4% if you do (78.7mm)

I personally don't consider the GTX3076R and GT3076HTA as having THAT similar compressor wheels, and wish FP posted compressor maps for the HTA wheels as it'd be really nice to know shaft speeds and compressor efficiency vs flow and pressure.

Still waiting for original poster to tell us what the actual relative driving experience is, he stated that there are places that the GTX3076R definitely has advantages but I've not seen an explanation for that hypothesis.

Tony the Tiger

There is always a trade of, whenever stepping up the turbine wheel..

I really liked 240Z TwinTurbo's conclusion, basically, it wraps up what you should consider with the turbo.

Two things when we overlay compressor wheels vs turbine, is that the GTX3076R is still going to be the best turbo before surpassing 500 WHP on a stock Evo motor.

What this means, is that UNLESS you are going past 500 WHP, the smaller GTX3076R turbine will spool sooner, respond faster, better transient response and quicker torque upon throttle movement. The GTX3076R will be much more "peppier" to drive around. There is no turbo that can replace the GTX3076R, because to reach 500 WHP and stay within 75% efficiency range, only the larger GTX3076R compressor wheel can do it. The smaller GTX3071R has a better comp/turbine ratio, but the wheel runs at < 68% at 500 WHP levels. Big difference.

In a drag race scenario, then the GTX3576R will reach 500+ WHP sooner or identical to the GTX3076R; so if you intend to run this turbo at 500+ WHP, it will spool and reach 500WHP the same or a bit sooner than the choked out GTX3076R turbine. This reflects on the dyno results, when the pull was done starting at lower RPM's and the turbo had lead time to build speed. The results will look very similar on a steady dyno pull between the two turbos. This can confuse some people regarding "spool". What we see on the dyno to what we feel when we mash the throttle are completely different things though

On the street, the GTX3076R will no doubt "reach" 450WHP quicker than the GTX3576R. So if the folks are concerned about stop light rolling races, the GTX3076R is still a faster spooling turbo off the line. The GTX3576R can maintain 500+ WHP easier, so it will be more responsive in a drag race condition between shifts, and off the 2-step out of the hole.

You can alter the engine too (for those doing a motor build) to manipulate exhaust flow vs WHP. Increasing compression ratio lowers BSFC, lower EGT's and less exhaust energy so it uses up less turbine flow. Longer runner exhaust manifold and nice merge collector will also make the engine see less backpressure. You can witness huge reduction of exhaust pressures just by building up your motor differently and changing certain things on your setup, so you don't have to dwell into finding which turbo works best. Rather, build the engine to match the turbo too get the best of everything.

I have had many occasions, on all sorts of cars and engines, between the GTX/GT30R vs GTX/GT35R... Regardless of what the dyno says, the moment you drive the car you'll notice the GT35 turbine is a much bigger turbo if everything else was identical on the motor.

03whitegsr

iTrader: (8)

I stated clearly I was simply talking the spool area, yes, I agree the 100 cell cat likely hurts power as power increases. However, with regards to the 350HP range (where this car is at during the majority of the "spool" time), I saw no difference at all on the mil-spec cat. No difference in spool or peak power. I have however seen the mil-spec cat spool significantly better then the typical 300 cell "high-flow" cat so if you are comparing to a typical cat, then I would agree, they suck.


The GTX3071R will do 50 lb/min at ~73% efficiency. It is definitely reaching the limit quickly by that point, but it's still capable of 500 WHP (based on the compressor map) with good efficiency. On kill mode, it should come close to 550WHP and LOTS of torque.

Seems pretty simple to me:
GTX3071R < 475WHP
GTX3576R > 475WHP

I personally see no point in the GTX3076R simply because the difference in response is looking to be pretty minimal with the GTX3576R. I'm biased though, I went with the GTX3071R.

It's still an odd fit on the EVO though, as I'd say if you want under 500, I'd stick to a stock frame setup.

240Z TwinTurbo

iTrader: (25)

You bring up an interesting point. Even though the FP BB turbo's are expensive, they are much cheaper to implement because they bolt up like stock. Therefore, you are not required to purchase a manifold, wastegates, and fabricate a downpipe.

With that said, there are some downsides to the stock frame turbochargers. Internal gates on these turbo's are less than optimal and you are restricted on your ability to upgrade and the setup is constrained by the turbine housing.

I wish one of the companies would offer the short runner manifold I designed (with single wastegate) using the 1.06 a/r T4 TS because I think it allows you so many options and has proven to provide great spool and good topend power.

Anyway, shipped off the GTX3076r and will be obtaining a GTX3582r for the GTX SHOWDOWN Part II. I just need to decide whether to risk the stock bottom end or wait unit May when I install a built 10:1 2L bottom end.

mynx87

iTrader: (1)

Very interesting read as I also have a GTX3076 I thought something was wrong with the turbo because it would take so long to spool I'm taking it back to the garrett dealer I bought it from which I will most likely upgrade to the 3576, based on these results of not much difference in spool, my car made 460whp 420wtq on a mustang dyno at 30psi bit we stopped there cause we thought something was up with the turbo so we didn't want to push it much further ill be posting a tread once I get retuned on the 3576 oh and these numbers were made on e85

mynx87

iTrader: (1)

A great write up on why we should all just go straight to the 3576

Garrett Releases GTX3576R Turbo GTX35R
http://www.enginebasics.com/Advanced...0GTX3576R.html

Grimgrak

iTrader: (3)

Well am I ever thankful for this thread however it does bug me that the OP never addresses why the gtx3076r was the winner.
Still waiting on that round 2 of the gtx 3576r vs the 3582r...

240Z TwinTurbo

iTrader: (25)

I am not sure I ever said the GTX3076r was the winner, but gave a rule of thumb. However, if I had to pick an all around winner it would be the GTX3576r. With the new 10:1 2L I am getting 31.5psi@4200rpm in 3rd gear with 93 octane.

GTX ShowDown Part II is coming, but not until after my next round of mods, which include a top mount manifold & 3.5" exhaust.

crx-si

Read what Tony the Tiger posted and that pretty much summed up the answer to your question. Depends on engines setup, ie cams/ported head/header design/ intake manifold/etc some turbo are more well suite to a certain combination than another. While one can expect a certain amount of result (spool time/ peak power/tq/etc) out of a specific size turbo, it will not always hold true everytime. For example: I used to have a basic gt3582r on my stock Evo 8 and was making around 500whp/e85, then I switched to a full race ts gt4088r. I was certain the 4088 will be much laggier than the 35r since its a much larger turbine/compressor, turned out not only that it made almost 60whp more at the same boost level as the 35r, it also out spooled the 35r almost 500 rpm. The transient response was incredible on the 4088r. Sometime reducing back pressure will improve spool, something like a larger ar turbine housing would help spool if back pressure was excessive with the previous housing. I don't know anyone on here ever attempted to use an external wastegate on a stock frame turbo to combat boost taper, I can tell you with an external gate it'd hurt spool vs the internal gate. The internal gate was opening sooner and before reaching max boost and therefore reduces back pressure vs the internal stay shut until it reachs max boost. Of course the external gate won't taper as bad and therefore more top end power. You'd be surprise once you have an idea what back pressure looks like.

AreSTG

iTrader: (4)

definitely looking forward to that! wish you were runnign a stroker so i didn't have to use my imagination, but it will be interesting nonetheless. Cerrtainly like your testing methods and results. thanks for sharing as always