Holset HX40 vs GT3076R

[GazzaG60]

but will that not effect the top end and primarily EGT. surely if its spooling earlier then the hotside is tighter.

will it require wastegate work to flow the gases past the hotside?

i hope you get what you want to achieve. it will be an interesting journey anyway.

[Jamo]

I've seen nothing quantitative in this thread regarding the Holset performance to be honest.

Be worth asking RS2002 who has a super HX40 and vems for his dyno plot.

[GazzaG60]

me neither. however im still open minded about holset and individuals quests for imrovements

so far its a bit like saying my new nike trainers are faster than the old adidas ones i have.

i think ill end up with my current opinion of compromise and if its around the same size and specs itll do about the same but i want to be enlightened about holset.

[loxxrider]

I have to agree that an HX35 is similar to a 3076. I run an H1C on my 3b. The H1C is nearly identical to an HX35 and the power level is like a 3076 so far. Maybe once I get over 1.5 bar it will be different.

[Billman]

I have to agree that an HX35 is similar to a 3076. I run an H1C on my 3b. The H1C is nearly identical to an HX35 and the power level is like a 3076 so far. Maybe once I get over 1.5 bar it will be different.

According to wheel sizes the hx35 is almost same as the gt35r. H1c have most of the times smaller compressor impellers than hx35.

However I thought that it is interesting to see that a turbo that is between the gt35r and the gt40r spools as the gt30r. Everything else is either way setup dependent and need to be proven. I hope someday to make it to a dyno and have more facts.

[Billman]

I've seen nothing quantitative in this thread regarding the Holset performance to be honest.

Same goes for cp but we hear them over and over...

[A80Avant]

then what is the reason of this thread? when or if you have facts, then preswnt them

to me, you wont be able to compare the 2 turbos because you have a completelly different than mine, and i wont do it either cause im not bothered!

[loxxrider]

According to wheel sizes the hx35 is almost same as the gt35r. H1c have most of the times smaller compressor impellers than hx35.

However I thought that it is interesting to see that a turbo that is between the gt35r and the gt40r spools as the gt30r. Everything else is either way setup dependent and need to be proven. I hope someday to make it to a dyno and have more facts.

35r is what...61mm? an Hx35 is something more like 56mm if I recall correctly. That is the same as my H1C as measured by me with a caliper (I have the biggest H1C, but with a 12cm^2 exhaust housing from an HX35).

[loxxrider]

actually, now that I think about it I believe its 57mm for the big H1C compressor impeller. Roommate who also has a big H1C confirmed this.

I think part of the reason that these turbos spool relatively well is because their wheel design (exhaust and comp) is superior to garrett's (not the new billet wheels though).

[Billman]

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.

[Jamo]

Same goes for cp but we hear them over and over...

CP have dyno results on these engines, some have been posted some haven't, I've seen quite a few and the results speak for themselves

I've only seen one claim that a hx40 did 700 bhp on a 2.2 5 cylinder audi, that was a finnish car

From what i've seen all the claims of super spool come from america with the little horses.

Comparing compressor sizes is a waste of time IMO also as the design of the blades plays a part.

The new Billet HPA wheels are smaller but flow more and are quicker spooling, granted being billet helps

[loxxrider]

If you mean HTA, then yeah...those things are awesome. Otherwise, Holset is the only way to go IMO in terms of blade design. Its funny that Holset's design was better 20 years ago than Garrett's was up until just recently.

[Billman]

CP have dyno results on these engines, some have been posted some haven't, I've seen quite a few and the results speak for themselves


The new Billet HPA wheels are smaller but flow more and are quicker spooling, granted being billet helps

I would like to see these dynos....

You are talking about CP billets dont you?
Garrett GTX (Billet) are only for large frame GT45 available).
Forced Perfomance HTA wheels are old design but billet (at least the ones i have seen in the net)

About inducers (whatever impeller design) there comes a point where the max air that can be sucked or pushed through a hole is achieved. The compressor inducer and turbine exducer point out the margins you can go. The middle and how you reach for these margins depends on the impeller design.

...and since these came up take a look at this from motorgeek. Top HP same (allmost identical). The billett help only spool up by about 200 RPM and this is not design related. it is because of the weight. The design of a compressor impeller has minor effect on the spool up time. HTA or not the turbine is the same.

http://www.motorgeek.com/viewtopic.php?t=34852

[A80Avant]

i thought that the larger major of the holset impeler only allows highee boost levels rather than anything else(extended tip). yes they can run 3+ bar of boost and that way you have all those horses.But as i mentioned before, my hx40 did not seem faster than my 3076 at 1.7 bar. timing is the same and he latter has juice up high on the rev range.

billman, your old setup with the hx40 with the 56mm impeller,at 1.3bar made around 350 hp on the same area whwn my 3071 made 420 with about 1.85 at the redline. i dont think the holset thwn could get +100hp only with 0.5bar increment and nothing more.

but that ia only my hunch.

[Billman]

i thought that the larger major of the holset impeler only allows highee boost levels rather than anything else(extended tip). yes they can run 3+ bar of boost and that way you have all those horses.But as i mentioned before, my hx40 did not seem faster than my 3076 at 1.7 bar. timing is the same and he latter has juice up high on the rev range.

billman, your old setup with the hx40 with the 56mm impeller,at 1.3bar made around 350 hp on the same area whwn my 3071 made 420 with about 1.85 at the redline. i dont think the holset thwn could get +100hp only with 0.5bar increment and nothing more.

but that ia only my hunch.

the 350 hp with is only a guess since we where not on a dyno but it was faster than my K24 7200 chipped. So i guess it was more than that....who knows.... but for sure 0.5 bar at the redline can shift yout compressor map from 68 or 70% effiency to 78% efficiency and that could make then maybe more that 80hp difference.