Holset HX40 vs GT3076R

[A80Avant]

Why compare HX40 with GT35R?
HX35 Super is much more comparable.

Here a graph posted on the forum in my country...:
http://mulk.planet.ee/S4_hx35super.pdf

if a HX35 Super (or hybrid as Billman posted on page one) is more comparable with a GT35, then the GT35 is much better if i judge from the power/torque output of what you posted, which as you have stated on another thread the car is heavily modified.

In comparison then, ill give you Doug (MRC) heavily modified S2coupe which has done 600+ with a GT35 turbo. SO nowhere near in comparison to a HX35 Super.

I still think the pairs to compare are:

HX35 variations to GT3076R variations (or even GTX)
HX40 variations to GT35R variations.

What one turbo gains in BB tech, the other looses in wheel design.

As Jamo said, unless tested on the same engine with the best optimal timing and boost characteristics to get the optimal profile, we can never judge absolutely what these turbos can do.
From my experience with them, i have already written in this thread what the results were.

If someone has the £££ and patience to give it a go, be my guest!

[prj]

I miswrote it earlier.
GT30R and HX35 Super.
GT35R and HX40 Super.

[A80Avant]

totally agree with that

[Jamo]

Yep that's better

[Billman]

In power output the super35 as sold By KKD is in the GT30 physical dimension. The hybrid HX35/40 somewhere between gt30 and gt35 dimension wise. The hx40 is clearly close to gt35.

[ian4455]

For what it's worth:

Compressor - Turbine
HX35: 56/82 70/60
HX35: 58/82 70/60 (rare)
HX35/40: 60/85 70/60 (Hybrid)
HX40: 56/82 75/65 (8 Major Blades on the compressor impeller)
HX40: 60/85 75/65 (6 blades called Pro and 7 blades called Super 40)

GT3071 53/71 60/55
GT3076 57/76 60/55 (aka GT30R)
GT3582 61/82 68/62 (aka GT35R)
GT4088 63.5/88 77/68 (aka GT40R)

Now you see where the impeller design plays a big role. All this time we comparing Holset turbos with 1-2 steps smaller Garretts. You see now what makes them (Holsets and in my opinion Schwitzer nowadays) so special....similar spool (or a bit laggier) with smaller garretts and big HP as big garretts.

In terms of high HP we want as big as possible both sides. Critical in HP number is maximum flow of the turbocharger that is always restriced by the Compressor inducer diameter and the turbine exducer diameter.

Bigger compressor exducer means more air flow at low turbo RPM.
Bigger turbine inducer means better spool at low exhaust gas amount.

Put now all over that the impeller design and you get the idea.

Any Holset Part Numbers for the above specs ????

[Billman]

maybe but something in particular?

[repo]

The whole thread is too long for me to read right now, but this has been neverending debate here in Finland, where Holset is the leading brand, and to try to sell other brand is like fighting the windmills.

I have said, and will stick with this, (cannot believe I say this) I agree with Vas. Holsets give staggering numbers for the price on dyno.

However dyno does not tell us how the turbo performs on real life. Now, when You apply throttle on second, at the same time as Holset picks up a bar at redline, a descent ball bearing hits max boost 2000-3000 rpm sooner.

Anyone who has NOT experienced this on same car, and with otherwise same setup, but a Holset vs. Garrett, has no idea what I am talking about.

Yet as it is usually too expensive for the people to try this out, very rarely we see people that have actually done it.

Now, I have tried them, in multiple setups, and I have seen enough to say Holsets are great on 4th gear and up, on dyno, and on quartermile (if racing with sportsman-tree, not pro-tree, not enough time to spool up). If You need to use gears 1-3, same caliber garrett (or other modern ball bearing unit) is better.

This is my last two pieces of eight on this discussion.

[A80Avant]

what id like to ask, is what happens if you stick a small hotside on the holsets? does that make a difference in smaller gears? How much does it affect higher revs?

[Billman]

The whole thread is too long for me to read right now, but this has been neverending debate here in Finland, where Holset is the leading brand, and to try to sell other brand is like fighting the windmills.

I have said, and will stick with this, (cannot believe I say this) I agree with Vas. Holsets give staggering numbers for the price on dyno.

However dyno does not tell us how the turbo performs on real life. Now, when You apply throttle on second, at the same time as Holset picks up a bar at redline, a descent ball bearing hits max boost 2000-3000 rpm sooner.

Anyone who has NOT experienced this on same car, and with otherwise same setup, but a Holset vs. Garrett, has no idea what I am talking about.

Yet as it is usually too expensive for the people to try this out, very rarely we see people that have actually done it.

Now, I have tried them, in multiple setups, and I have seen enough to say Holsets are great on 4th gear and up, on dyno, and on quartermile (if racing with sportsman-tree, not pro-tree, not enough time to spool up). If You need to use gears 1-3, same caliber garrett (or other modern ball bearing unit) is better.

This is my last two pieces of eight on this discussion.

I dont intend to question your knowledge on the subject but I would like to know how do you measure spool times.

I did a couple of days ago a small run with my car 3rd and 4rth gear and with a rough tune i have seen the following:

I had 1 bar at 3900 RPM and hold it till 5700 RPM. Then changed to 4rth and i had 1 bar again in 0.9 sec (measured from the log from -0.3 bar). Note I didn't try to make the change as fast as possible to measure....i simply see this now in the logs.

Now, how long does the equivalent Garrett BB GT35R need to respool? Or are you talking about spool times in 1-2 gear?

One must also see that most people in Finland the original Holset 16ccm housings use that are great for top end power (less restrictive but hurt spool). Consider these are 1.1 AR housings.

[repo]

From above:

This is my last two pieces of eight on this discussion.

I will not waste my time on this anymore. Like said, fighting windmills. And Billman above only verified it.

[Billman]

hahaha.....very nice. Thanks for sharing!

[Jamo]

Transient boost response can't be seen on a dyno is what is being said
No doubting Holset can put down good figure trucks having 2000 bhp in some cases

[repo]

Sorry, I read Billmans post too fast, first thought he was trying to prove his Holset spools ultraquick and outperforms everything, as I have seen too many times before, from Holset religious, and they very rarely have nothing to back up their claims. Perhaps I can still spend a moment on this.

With ball bearing 81 mm compressor I was able to achieve 2 bar on neutral in less than 0,4 seconds without using antilag.

With 81mm Holset it takes more than 2 seconds to do 1,2 bar, and I was unable to get more without using antilag.

With 6567 comp, from steady speed on third gear (mild vacuum) at 5500rpm I dip the throttle and get 2,1 bar in less than one sample in datalog, meaning 50ms or less.

With 77mm ball bearing after gearchange it took 0,2 seconds to get back from vacuum to 3 bar, changing from 2nd to 3rd. No antilag, stock h-pattern gearbox, using clutch with foot.

With 67mm Innovative we got 3 bar before redline on 1st gear, and never gor over 1,5 bar with HX40. Drivers initial impression with Holset after ITS was "holy crap this is slow".

At the end of the day we did make 10.002 pass with HX40, when best time we ever got with 67mm ITS was 10,2, as we lost traction on first and second with innovative. This was running on non glued track and Toyo Proxes 888's.

I have over 10 000 logs on this computer. I could try to find something, but then again, I don't think it would turn a single head, neither for nor against.

[Billman]

very interesting! This holset i am using now has 60/85mm compressor and 75/65 turbo. Do you remember if these Holset you tested had the holset 16 or 18 ccm housings or an aftermarket smaller one?

The machined K26-6 on the HX40 on the stock engine spooled quicker than the HX35/40 hybrid with the 16ccm turbine housing on the 2.5 stroker.

Please remeber the following: I am not a tuner, the car has a cast MTM manifold, stock RS2 cats, I use an Ebay intercooler, stock RS2 intake manifold and path, reclocked 7A cams. All the above and mainly the first affect spool :-D