Bjans

who makes it? how much?

XLR8R

LazarSmith

Link is in the previous post, if you want to check prices.

Big Blue24

XLR8R, that is a sweet looking setup. Probably not quite in the budget for this experiment.

You said 75 psi DP with 45 psi boost @ abt 500 HP. Any ideas on how high the intake air temp is? Both before and after Charge Air Cooler. Based on your numbers, do you think I should gate it to peak at 45 psi, or 40 psi? I'm not a firm believer that 1:1 ratio = peak HP on the dyno when you have extra fuel to burn.

I just want to rig up a DP gauge to compare the ole HX with the HE. Boost vs DP.

XLR8R

Obviously, that's a drive pressure ratio with overfueling!

The differential is usually 5-10*F during normal driving, and if you don't heat soak the intake tract (like WOT under load for 15 minutes), it never really exceeds 25*F.

The OEM CAC does a pretty good job maintaining that differential even when the hot side is 375*F.

An HE351 at 40psi is definitely off the efficiency island of it's map, but it'll keep making power to 50psi... but I wouldn't recommend it.

Also, it's tight, quick-spooling hot side means that the drive pressure ratio is in the 1.25:1 range, until you pass 35psi - then it just goes increasingly ballistic, for instance:

40psi = 50TIP
45psi = 75TIP

Big Blue24

Sweet, with those numbers, I can see how good of a port job I did on my wastegate once I get everything installed.

Big Blue24

Alright, I found a questionable compressor map for the HE 351 and the HX 35.
I found a map identical to the first one on a DSM site labeled HX 35, so who knows. Flows look a little low to me.

Now someone smarter than me needs to interpret them "insert Hohn" and tell me if there is anything to be gained going with the HE 351 based solely on compressor efficiency and disregarding hotside factors.

I will port/ modify the hot side till it flows as it needs to, I'm more concerned with compressors right now since I cannot change or modify it.

Big Blue24

According to the map, maximum mass flow of air happens at 3:1 ratio or right about 30 psi boost pressure. Now I'm sure we can overspeed the compressor and get a little more flow and get off the efficiency map, but how far and at what psi is max HP potential obtained? Obviously the further off the map you go the more exponential the super heating and loss of mass, so I'm gonna guess 35 psi is going to be the magic number. But others please speak up, I want any and all opinions.

Big Blue24

Well guys, I found that identical map on a DSM forum stating it as an HX 35 map. So now I don't know. I did find some holset produced HX 40 maps. I'll post them up as well.

kawi600

Does grinding the ports out like this do anything to the power curve like move low end response up in the higher end of the rev range? or does it just allow it to breathe better all around on a diesel?
curious if I should be doing this when I get a larger single.

Ph4tty

The map you posted for your turbo tells you that it will flow around 20 lbs/min less than the hx35 and 23 less than the hx40. That'd be the point at which I'd shut down shop and move on

Unless this is the right map, then you might be okay:

Big Blue24

Well, I wasted a whole day taking off my stock HX, and then trying to fit up my downpipe and new cold pipe. Looks like I'm gonna have to wait a few more days for another 3" silicone elbow, I need another 45*.

Anyway, I put the stock system back but before I did, I measured the wastegate puck and passage.

Stock HX 35 puck 1 3/32" or 27.78 mm

Stock HX 35 passage/opening 3/4" or 19mm.

So the HE351 wastegate is bigger.


I put a stock elbow back in my HX and with the Adrenaline on 10, I can only hit 30-32 psi boost. Big seat of the pants difference between letting the stocker run up to 40-43 and having it gated at 30-32. Although drive pressures surely soar, you certainly make more power pushing past the map and into grenade territory.

I think that my modded wastegate HE 351 will bypass plenty to keep my motor happy.


Here's a few pics of my quick port job.

XLR8R

I think you'll enjoy your new Holset; sure, a HPCR will get more out of an HE351 than your 24V, but your 24V will get more out of the HE than the HX...

Big Blue24

I agree, I can't wait to get the last few parts and get her installed.

Hammer

I am still trying to figure out how a 9cm exhaust housing on the 3rd gen turbo is going to outflow the 12cm on his HX35?.Did I miss something in class here??.....

HOHN

I dunno if the "Xcm" housing sizing system that Holset uses is relative to turbine size like A/R is.

If it is, then a "smaller" housing on a larger turbine could theoretically flow more.

But I have no idea what the Holset system represents, and why they still use it when no one else does.