twin turboing a ve pump
#21
#22
So by the math, this is unfortunately still in L/min because I have not finished my spreadsheet to convert this into kg/min.
At 2250 RPM, assuming a volumetric efficiency of 80% a 5.9L should consume 187L/min of air at 0Psig, 20 Celsius ambient.
At 2250 RPM, with 3.6Psig a 5.9L should consume 209.0L/min of air at 62.7 Celsius at the compressor outlet.
At 2250 RPM, with 8psig a 5.9L should consume 239.5L/min of air at 90.2 Celsius(100C is the boiling point of water at sea level.)
Perhaps this bit of math doesn't apply and I'm still missing part of the equation, but here is what I think about.
If the engine can pull the weight of my truck, empty, at highway speeds with fuel alone and no boost without feeling bogged down, which crusing speed is about 2200ish RPM with my setup and if I tip in, even lightly I quickly start to see positive manifold pressure, it leads me to believe the engine is not struggling or "lugging" to maintain that speed.
If, due to installing a smaller housing my truck sees boost under the same conditions then I am adding load to the engine, in that I must now move more air and compress some of that air adding some additional restriction to the exhaust stroke. If I have to move more mass of air and fight the additional back pressure then I must use more fuel. It takes greater effort during the compression stroke to compress the extra air, but some of these negatives are balanced by the manifold pressure during the intake stoke.
I have read enough threads of people complaining about loosing fuel mileage at highway speeds when going to the smaller housing to make me think about the fact I'm not bothered by a little bit of lag. When I'm empty the Cummins without boost can easily throw my truck around and I usually cannot see more than 20psig before I run out of rpm, until I'm in 4th and 5th, where I'm topping out at 26psig right now.
Towing a load I'm not racing anybody and from my experience driving class 8 trucks, my 5.9L is more than responsive enough in its current form for my towing needs, I just want more total available power without sacrificing empty crusing fuel mileage. As it stands right now my truck is hovering around 9-10L/100Km(can reach the low 13/100 if I roll out too much coal). My car is around 13/100, the LMM duramax I drive is around 14.4L/100 and the bosses 6.4L is ranges from 16-19L/100.
Remember, turbochargers are not free, it takes energy to make boost, just significantly less than a supercharger. It takes back pressure against the turbine housing to produce enough pressure and force to produce positive manifold pressure.
This is the main reason I've been looking at the HX55 as the low pressure turbo, I might even go smaller, in order to increase the responsiveness of the low pressure turbo, so as soon as the high pressure starts to make boost and enough mass is moving the LP kicks in and hard, working together with the HP.
I admit I still must take this from the math, to the reality phase and with everything mechanical there is always art form involved in getting things to work the way you want them to. We'll see what happens, this winter the Cummins is getting yanked and fabrication begins.
#24
#26
ive been kicking the idea around in my head of using my h1 in a twin setup. my truck is 93 model so im assuming its 18cm exhaust housing i recently bought a gds 60mm comp housing which helped alot but still slow spooling till bought 10psi. so my question is instead of starting all over with another turbo why not put a smaller exhaust housing (12cm) on it and later on build a twin setup. from what i know a hx35 is a 56mm with 12 or 14 cm exhaust side? correct me if im wrong but wouldnt a h1 with a 60mm and 12cm be just as effective or even better? only difference is no wastegate. i dont know much about turbos but seems sensible to me to make decent power in the 400hp range
#27
they will be close. The HX35 has a little better wheel design. Size is not everything, its alot but not everything. since you already have teh GDS upgrade I would look for a 14cm housing cheap to swap on and see how that feels. Your still dealing with the relativly weak shaft on the H1C though. Theyu dont like to be over spun and dont like real high boost (which in that small turbo wont make any power anyway)
#28
thanks RSWORDS. doesnt the the gds housing i have also fit a hx35? or did i dream that up? il prolly buy a 14cm housing someday and just stick with it untill i decide to go a lil crazier with my setup. i was just curious as to how well my h1 with 60mm and a smaller housing would work in a twin setup. thought it might be a cheap way to build a lil more power. if i could find a cheap hx35 could i swap my 60 mm housing over to it? would that be a better and more reliable turbo than upgrading my exhaust housing?
#30
i love my hx35-hx55 setup empty i can only hit 900* foot to the floor , towing i can only hit 1000* foot to the floor,( and that is towing a 25' tandem dually goosneck with a john deere 410J backhoe in the mountains). my setup is not laggy at all and makes great power at 404hp and 880tq.