OMG!!! Twins Rock part II

[Mark_Kendrick]

The last one got closed. .



read it here... .

https://www.turbodieselregister.com/forums/showthread.php?s=&threadid=55180&perpage=15&pagenumber=1



Any new comments? questions?

 

[KatDiesel]

If this one goes astray like the last one... ... it'll be closed as well.



And nothing new..... but drive pressure? drive pressure? Hehe ... You might decide your 12cm² housing is a bit small... .



Then again I could be wrong since... ... .

 

[HoleshotHolset]

I'm gonna get flamed for this but who cares... .



IMHO, we're worring about something that is less of an issue with Mark's setup.



He's bypassing quite a bit of exhaust gas from even entering that "Oh my good gracious that's a small exhaust housing!!" by using that external wastegate which dumps into the pipe that connects the exducer of the turbine side on the primary to the inducer side of the secondary turbine.



He's getting good spool by using the 12cm² housing... and then the instant the pressure (read: drive pressure) gets to be too much, the external WG dumps it into the secondary's exhaust turbine inlet.



My point is that it works... . and if it works well and makes him happy... who gives a (insert your favorite expletive here!) ?!



Anyone with twins is sacrificing not only reliability, driveability... . they're also sacrificing their wallet. Increasing plumbing and moving parts is a tried and true formula for increasing the likelihood of a failure. He's doing this on his own dime and could very well be taking a risk.



If it blows up and costs the GDP of a small island country to fix... . who cares?! That's what happens when you want to make more HP.



I once again applaude him for sharing his knowledge... . and for his contributions to the advancement of our hobby.



Matt

 

[Jetpilot]

Dang here we go again.....

 

[KatDiesel]

Originally posted by HoleshotHolset

IMHO, we're worring about something that is less of an issue with Mark's setup.



He's bypassing quite a bit of exhaust gas from even entering that "Oh my good gracious that's a small exhaust housing!!" by using that external wastegate which dumps into the pipe that connects the exducer of the turbine side on the primary to the inducer side of the secondary turbine.



He's getting good spool by using the 12cm² housing... and then the instant the pressure (read: drive pressure) gets to be too much, the external WG dumps it into the secondary's exhaust turbine inlet.



My point is that it works... . and if it works well and makes him happy... who gives a (insert your favorite expletive here!) ?!



Anyone with twins is sacrificing not only reliability, driveability... . they're also sacrificing their wallet. Increasing plumbing and moving parts is a tried and true formula for increasing the likelihood of a failure. He's doing this on his own dime and could very well be taking a risk.



If it blows up and costs the GDP of a small island country to fix... . who cares?! That's what happens when you want to make more HP.

I'm sure its less of an issue then its being made out to be.



He said he is sharing this information with other people, so say if it blows up... . then thats what happens. Thats perfectly fine on his truck. If hes going to "sell" or share this with others..... is it fine if their set blows up too?



This is what I am trying to avoid.



Personally I HOPE his drive pressure is inline... ... ... . however without checking it he won't know. I'm just trying to get him to check it is all... . ANYTIME your playing with turbos... drive pressure is a key issue.

 

[CTHOMAS]

Need help

I have a problem with my turbo spooling up to slow. I see alot of y'all using twins to get the boost up higher along with the spooling response. So,I got the H2E on the truck now w/17 cm housing,this is a PSD by the way. What could I put in front or in back of it to either feed or supply it?The Dodge fellows have been staging turbos longer than the Ford guys so I come to y'all for this question. Also Johnboy3 . Thanks in advance

 

[Mark_Kendrick]

My problem is I don't know what stock drive pressure is like.



as for a PSD. . think triples two turbos feeding one. . plumbing nightmare though anf the bottom end of a PSD wouldn't last long



Kat, I'll try to get a drive pressure gauge set up before saturday.

 

[CTHOMAS]

Mark,is there any other housings for the H2E you know of?This help with the spool up but may hurt the upper end pressure... ... ... ... ... ... ... ... ... ... ... ... ... ... ..... I guess one these days I'll have to swap in a Cummins

 

[Mark_Kendrick]

h2e 17 is the smallest w/o going to a hybrid. sorry.

 

[J.R. Adkins]

C_Thomas,



There is a guy here in Indiana that is runing a hx40 on his PS! He has done fairly well with it to . But it is on drugs!! A smaller turbo might help?







J. R.

 

[cmonroe]

Drive pressure, where do you guys think this should be limited? Does the external wastegate become a liability? Mark how does your wastegate in theory work better? I'm not use to using a waste gate. Always left home without it!

 

[kaffine krazed]

A couple of questions. What is drive pressure? I'm assuming it is the pressure before the turbo on the exaust side of the system. What kind of drive pressures does a stock truck make? How about a bombed single turbo system. Twins? What do you want to keep drive pressure below?



The external wastegate. It takes exaust gas and diverts it around the small turbo to drive the larger turbo to keep EGTs and I assume drive pressure in check? What opens the external wastegate?



Does anyone know of good books that talk about turbos particaliarly seting up a twin turbo setup and variable geometery turbos. The only books I can find are older than I am. Thanks.

 

[CTHOMAS]

Thanks J. R. I might try to find a HX40. Anyone want to trade one for a HX55 I may look into doing twins witha pop off valve to limit the boost to 40-45 psi. Our head gaskets can't take but so much How about using the HX55 to supply the H2E?Would this be a good set up?

 

[Mark_Kendrick]

Here's some info from anither thread....

https://www.turbodieselregister.com/forums/showthread.php?s=&threadid=54528&highlight=drive+pressure[



QUOTE]Originally posted by Diesel Freak

This week I got off my butt and finished the Dial a Boost for my turbo. I will be running the turbo at Diesel Thunder, even if it is to my detriment on the dyno... but it will make up for it on the track

(this turbo spools up at any RPM!)



but all my smoke is gone



I installed the turbo on my truck and set the wastgate to open at 33 PSI.



a couple of interesting things happened. With lower boost than the stock turbo: a HX35/14 set for 38 psi, my new turbo ran noticeably cooler at WOT with less boost. I attribute this to the HX40 compressor wheel.



I decided to check drive pressure also.



Boost pressure is sensed at the intake horn, and drive pressure was senced at the exhaust manifold Pyrometer port.



4psi of boost required 4psi of drive pressure

10 psi of boost required 12 psi of drive pressure



and here is what I was worried about

33 psi of boost required 40-45 psi of drive pressure.



there is room for a seccondary turbo. With the wastgate set to open at the OEM HY35 setpoint, I could only make 25 psi of boost,so I am hoping with the addition of the H2E I should be able to bring boost up to 45-50 psi with little rise in drive pressure. [/QUOTE]



Granted, this is with what appears to be a hybrid. looks like a 35/14 with a 40 compressor. I would expect drive pressure to rise over stock with a bigger pinwheel but the boost numbers are not relative. . he's now making cooler boost and achieving more power on less boost due to temperature of intake air but also making what seems to be higher drive pressure. In theory anyway...



I'm seeing that drive pressure is implied to be ~60% of boost at high pressures in this setup(from DF). i'll be curious to see what mine look like

 

[HoleshotHolset]

Kat: I agree... . excessive drive pressure is never a good thing. My point is that if it works well, then leave it alone until it blows up.



I also agree that if anyone were to purchase a setup that it should be tried and true, however I don't ever remember seeing anyone that offered any sort of warranty or guarantee of reliability with any twin turbo setup.



It's risky... . but don't forget... we're racing!



Matt

 

[Mark_Kendrick]

I know of several different twin setups that 'melted down' . I'll not list them. . but like you said, 'It's racing". If you use this to make your towing EGTs lower you'll never have much issue. At that level you're really not working it that hard. It's the 70+psi 120+mph runs where these things are on the line.



$#!^ breaks at the track!!!

 

[smoky]

12 valve

WONDER HOW THESE WOULD DO ON A 12 VALVE????????

 

[Diesel Freak]

Re: Here's some info from anither thread....

Originally posted by Mark_Kendrick

https://www.turbodieselregister.com/forums/showthread.php?s=&threadid=54528&highlight=drive+pressure[



QUOTE]Originally posted by Diesel Freak

This week I got off my butt and finished the Dial a Boost for my turbo. I will be running the turbo at Diesel Thunder, even if it is to my detriment on the dyno... but it will make up for it on the track

(this turbo spools up at any RPM!)



but all my smoke is gone



I installed the turbo on my truck and set the wastgate to open at 33 PSI.



a couple of interesting things happened. With lower boost than the stock turbo: a HX35/14 set for 38 psi, my new turbo ran noticeably cooler at WOT with less boost. I attribute this to the HX40 compressor wheel.



I decided to check drive pressure also.



Boost pressure is sensed at the intake horn, and drive pressure was senced at the exhaust manifold Pyrometer port.



4psi of boost required 4psi of drive pressure

10 psi of boost required 12 psi of drive pressure



and here is what I was worried about

33 psi of boost required 40-45 psi of drive pressure.



there is room for a seccondary turbo. With the wastgate set to open at the OEM HY35 setpoint, I could only make 25 psi of boost,so I am hoping with the addition of the H2E I should be able to bring boost up to 45-50 psi with little rise in drive pressure.

Granted, this is with what appears to be a hybrid. looks like a 35/14 with a 40 compressor. I would expect drive pressure to rise over stock with a bigger pinwheel but the boost numbers are not relative. . he's now making cooler boost and achieving more power on less boost due to temperature of intake air but also making what seems to be higher drive pressure. In theory anyway...



I'm seeing that drive pressure is implied to be ~60% of boost at high pressures in this setup(from DF). i'll be curious to see what mine look like [/QUOTE]



Mark the turbo is a HY35/9 with a HX40 Compressor wheel. Drive pressure with this turbo is lower than with a stock HY35/9. Does anyone have a HX35 Turbine shaft that they can send me? I just want to measure shaft leingth, journal diameter, and piston diameter. Then I can send it back to you.



Mark, I would hope that your drive pressure does not exceed 40-50 PSI at peak boost AND (the critical part) Peak engine RPM.

 

[Mark_Kendrick]

How is the drive pressure lower with the bigger cpmressor wheel? the bigger wheel is heavier and the fins get a bigger bite of air. . this should increase the resistance for the turbine to overcome. You are also increasing the amount of air in the motor with the bigger wheel. . this creates more exhaust so now you are forcing more air through a turbine that has more resistance to motion but somehow drive presssure drops????



I'm not questioning the the results but why it worked. What were the pressures like stock? It just doesn't make sense.



Thx,

Mark





Smoky. . I think you'd have to use a bigger exhaust housing on the 35 but it'd work fine. I got to talking with Al at piers about P-pumped engines and fuel flow. The 12v engine flows a lot of fuel even in near stock form causing a need for an 18 or 21 housing. . i'd bet.

 

[Diesel Freak]

basicly is comes down to having a more efficient compressor wheel that is operating closer to it's "sweet spot" on the map. It does not have to spin as fast as the smaller wheel to move the same ammount of air.