HX35 VS HY35-D

[Cowboy]

Did some turbo swapping on the '96.  Went from the older 8 blade HX35 to the HY35-D found on 03-04 dodges.  To make the swap easy, I used a HY35 turbine housing off a 2nd gen.  This turbo is a 56/58/9W instead of the HX35's 56/60/12WD.

 

I expected faster spooling, and possibly a less restrictive top end... I was wrong. The top end pulls a little harder and spooling is amazing, but down low just doesn't cut it.

Here are the runs:

RPM, Here you can see the HX35 took off much faster.

 

Pressures, Again, spool-up on the HY was noticeably slower, but the top end did well. 60psi Drive pressure all the way to 3400RPM. For anyone wondering about the funky drive pressure curve, the peak happens about 27-2900RPM, and does that on all 3 runs.

 

EGT's were slightly higher with the HY35, but I believe that was because the extra time the run took. Because they were actually climbing at a slower rate.

Obviously, with tuning you could get better, but for a back to back comparison, this shows it pretty well.  So if you live above 1800 RPM like with an auto, this would be a good upgrade, better power up top, and spool above 2000 RPM is to die for (or from).  However I miss my sub 1400 RPM boost, it was definitely much torqueir down there.  So I'll play with other turbo options and see what I can get.

Edited February 4, 2016 by Cowboy

[Me78569]

you know for a guy that likes to tinker I know just the setup

[Cowboy]

I would drive myself nuts trying to get the right tune.  I like trying different things and see how they work.  I may end up with one, at some point, who know.

What would be really cool is if someone let me 'baby sit' there truck for a little while, and didn't mind if it was making 800hp and if there bank account was a little less full then before.   

[Me78569]

haha that is the dream isn't it.  

 

I did notice yet another nice feature of the VGT, sudo traction control.  the larger the vane curve the less you run the risk of blowing the tires off, actually VERY helpful for pulling people out.

[Cowboy]

It's hard to explain my 'low-traction-pulling-others-out' method.  It's like a mix between Jeremy Clarkson and a Sled Puller.  

 

[Me78569]

[NightHawk]

Out of curiosity, what was the boost vs. drive ratio curve by itself from 0 to total boost?

The spool-up on the HY with my mild fueling setup is so quick it sometime catches me off guard, maybe you have a boost leak or waste-gate issue (if running one) ?

My truck Hy stats (no drive pressure, )

• 35/40mph in 3rd lock @ cruise    2-3psi & 500-600* egt
• 45/50mph in 4th lock @ cruise    3-5psi & 600-650* egt
• 65/70mph in 4th lock @ cruise    5-7psi & 650-700* egt

• 35mph to XXmph (brief cruise to WOT) in 3rd lock   3-28psi & 1000* egt (let off when boost hits 28, but sure it can go over without a waste-gate, not going to try though)

Edited February 5, 2016 by NightHawk

[Cowboy]

One thing to keep in mind.  The stock HY35 on 2nd gen has a 54/76.5mm compressor wheel, this one has a 56/76.5mm compressor wheel.  So it's not quite apples to apples.

From the limited testing I've done, this turbo is great for automatics.  Because you rarely spend time under 1600 RPM, and if you try to get into it to hard the TC will unlock.  The spooling on this turbo above say 2000 RPM is very good, it just doesn't do as well below ~1600ish.

I don't have a whole lot of data collected, I do plan on doing more testing at a later date, but  I need to makes some fueling changes in the mean time.

On the boost:drive pressure ratio, you can see the middle chart above, it shows the boost and drive pressure.

I did data-log the way back from my runs so here is some of the info I got.

Cruising ~35 MPH, 1350 RPM.  Boost: 3.6 psi, Drive: 4.5 psi.

Pulling a Hill 32 MPH, 1275 RPM. Boost 5 psi, Drive 5 psi.

Pulling a Hill 40 MPH,1500 RPM, Boost 12.9 psi, Drive 12.1 psi.

Cruising 40 MPH, 1500 RPM, Boost 4.2 psi, Drive 5.1 psi.

 

Also, I do have a wastegate, due to the larger compressor wheel I set it to 35 psi.

Edited February 5, 2016 by Cowboy

[Me78569]

Very interesting data after rereading it.  

 

good point about auto's rarely seeing under 1600 rpm.  that does make a considerable amount of difference.  

[NightHawk]

16 hours ago, Cowboy said:

One thing to keep in mind.  The stock HY35 on 2nd gen has a 54/76.5mm compressor wheel, this one has a 56/76.5mm compressor wheel.  So it's not quite apples to apples.

I did data-log the way back from my runs so here is some of the info I got.

Cruising ~35 MPH, 1350 RPM.  Boost: 3.6 psi, Drive: 4.5 psi.

Pulling a Hill 32 MPH, 1275 RPM. Boost 5 psi, Drive 5 psi.

Pulling a Hill 40 MPH,1500 RPM, Boost 12.9 psi, Drive 12.1 psi.

Cruising 40 MPH, 1500 RPM, Boost 4.2 psi, Drive 5.1 psi.

 

This is awesome data on the HY turbo in general 

The chart was bunch together/small so would it be possible to post a version with a expanded data range to spread the numbers out?  With boost & drive being in the 1:1 range up to 12psi makes me wonder if the so-called internet "limit" of a 32 psi max due to excessive drive pressure is really true.  Consider is jumps to 2:1, 60psi drive vs 30psi boost is not terrible, although efficiency is dropping off fast.  Do you have on hand the true boost/drive at say 20psi, 25psi & 30psi?

I run mine non-gated as it picked up sub 20psi response over a j-hook with a spring. No matter how tight the wastegate j-hook with spring was, it always felt as if the truck would start to drop drive pressure well before required.

 

Edited February 6, 2016 by NightHawk

[Cowboy]

Again, remember, this is a HY35 but with a HX35 compressor wheel, otherwise known as a HE341.  

On the wastegate I understand 100%!  With the HX35 I made my own wastegate actuator that put a "banks bighead" plumb to shame, and I also designed a boost governor, which basically plugged the wastegate until my set pressure is reached then opens it as needed to maintain your desired boost.  So if it's set at 35 psi, the wastegate will be closed and no pressure in it at 34 psi, and fully open at 36 psi.  The plate that goes over the wastegate had a dent from the wastegate opening all the way and hitting it.  

If you can rig up a way to run a boost line from compressor to wastegate that you can hook a boost governor into, I'll make you one and you can have it at cost, just let me know what you think of it.

On this HY35-D I enlarged the wastegate to 29mm and am running a spring gate.  I need to measure everything again, but I'm pretty sure that it doesn't open till at least 20 psi.  

Maybe I'm misunderstanding you, but you said that boost:drive is 1:1 till 12 psi?  The charts below are easier to read, they are actually 1:1 till about 25-26 psi.  One thing to remember though, boost:drive ratio, especially on these smaller turbo's/turbines are largely dependent on RPM.  With the HX35 I got 10 psi boost and 6 psi drive pressure at 1200 RPM.  But at 2800 RPM, boost is 24, and drive pressure is 35.  1800-2100 RPM was the happy spot for the HX35, it ran about 1:1 regardless of boost, but spooling was still very fast.

Is this easier to read, the X axis is RPM.  If you would like me to format it differently let me know.

Also, you can enlarge my pictures by clicking them.

HY35-D (HE341) 

 

HX35

 

 

Edited February 6, 2016 by Cowboy

[NightHawk]

Its fully understood its an HE341, however from the specs below from Comp D/research indicate the HY35 & HE341 share the same exhaust side which is why this information is awesome. It seems that no-one cares about the small housing turbos, but more of those on the road then anything else. The rpm problem will never be an issue with a vp truck .  I probably have to do research on this site, but do you have a write up on the boost governor?

HY35
Turbine Wheel
58/65
Comp Wheel
54/78
Housings
T3 9cm

HE341
Turbine Wheel
58/65
Comp Wheel
56/83
Housings
T3 9cm

[Cowboy]

That is correct, the HY35, HE341, and HE351 all have the same turbine.  However the HY35 has a 54/76.5  and the HE341 has a 56/76.5.  These are measurements I personally took and compiled here.

 

I don't have an updated thread on the boost governor, but here's an old one, but the internals have changed considerably.

If you're thinking about building one, let me know, I'm pretty sure I can make one and ship it to you for cheaper.

 

 

[NightHawk]

The boost controller was an interesting read.  I am now left wondering how a Hy35/HE351 combo would be on one of these 2nd gens.  The HY exhausting housing per this thread would bolt up, guess someone needs to be see how well the HY compressor housing would work when machined for the larger wheel.

[Cowboy]

They sure do as I've done it, never installed it on the truck, but was just curious.  There is some hear say about the HE351 having a 9.7cm2 turbine housing, however I nor anyone I know is sure on the matter.  The advantage of the HE341/351 is the wastegate design.  It can be enlarged further and flows better by design.  But if you don't plan on over fueling it to bad you'll be fine.

Another thing to consider is just installing a HE351 compressor housing as well, they have a larger AR so would probably work better with the extra flow.