turbo gurus teach me

[Mhannink]

ok so we where talking turbos today in class and a couple of my classmates and i talked about it more during our brakes. i understood it fairly well but i want to understand it completly. the 2 biggest things i want to understand is a/r ratios and how they affect the turbo. the other thing is in a twins setup wich way works best performance wise to plumb them. on the twins i always understood it to be is big into small small into engine. they way our instructor and a couple of the kids said was small into big and big into the engine. what are the differences in them and wish way does it really matter. those are the big things i want to know as much as i can about these mysterious little power adders

 

[Mhannink]

no one know im sure some one on here does. i want to have a disscussion on this not just for my benifit but for all. so lets talk turbos

 

[ThrottleJockey]

Your instructor is wrong. A turbocharger is a compressor. Small into big wont offer staged compression, the small one is in effect, too small to 'feed' the big one. Generally, the air filter is affixed to the larger of the two turbos, the smaller one is plumbed into the intercooler, and subsequently, to the engine.



Understanding staged compression, or compounding boost, is easy. It's the math that gets hard. Turbochargers are stupid, or I should say boost is stupid. Meaning that 30 psi force fed into another turbo will result in something like 92 psi out of the following stage! Depending on size of the second stage. Fun, right?



Do a search on 'twins' and read up!

 

[Mhannink]

k well first off i must correct an error i looked at the engines that are set up with the twins and they are as i thought big into little little into engine. i may have heard the instructor wrong or he said it wrong either way i talked to him about it today and he said it the right way before i corrected him. anyways enough of that. i still want to learn throttle jockey can you explain more about this id like to see the math if its not overly complex. this brings up a question for me as i have started looking at putting a twin on my truck. now i want to use an hx35 on top and my 62 on bottom. how much boost fuel being unlimited could this thing produce efficently? enough for studs?



this is my weak spot ive never really been able with all my searching find just how this all works out what the math is how the 2 affect each other and so on.

 

[Mundgyver]

Your engine will be good to around 45 or 50 psi on an intermittent basis. With a single you can get into the high 30s and low 40s depending on what turbo and other factors. With twins, you will be able to increase your boost well above 50 psi.



If you plan on using twins to produce big power, then your question on studs is answered. More power and what is the weakest thing that is going to break. You will want to do the studs before you do the twins.



Nothing worse than making lots of power and TQ and then having it excape due to a blown head gasket.



Your best method of upgrading is to decide what your target is, then bullet proof the weakest spots before you go big. In the long run you will have a dependable ride that you will know inside out.



Now on the other hand if you have money to burn and throw at it and don't care, GO LARGE and don't worry about the carnage that you are about to inflict upon your pocket book:-laf

 

[Mhannink]

well i understand that you have to stud it first. but my plan for now would be to wastegate the turbos at 50psi and leave it till i get studs. im looking for faster spool up the turbo i got lights kinda slow. when i get studs ill turn the pressure up and go.



now with this setup would just one waste gate be enough to keep it under 50 or would both need to be wastegated. i ask cause my wastegate right now is not hooked up due to clearence issues. that will change though when it gets moved down

 

[Mundgyver]

If you have an air compressor and a good inline regulator, you should be able to set the wast-gate dump pressure statically with no problem. All you need to do is cap off the outlet and then cover the inlet with so you can apply regulated air pressure to the turbo housing and then set the wast gate to move at what ever pressure you want. Or you can take the air and feed it directly into the sensor using a regulator to slowly bring the pressure up and make the adjustment that way.

 

[ttbird]

Stock head gasket and no studs. I think head gasket is toast very quickly at 50psi.

 

[Tinman]

How does the Ford 6. 4 get away with running the small turbo into the big? (I think that's how it's plumbed. ) Sounds crazy to me.

 

[Mhannink]

Stock head gasket and no studs. I think head gasket is toast very quickly at 50psi.

my truck in paticular has held 60+ completly stock top end. my understanding too is that 50lbs is the limit of ok past that and you'll start having problems.

How does the Ford 6. 4 get away with running the small turbo into the big? (I think that's how it's plumbed. ) Sounds crazy to me.

i have heard this to and the only thing that makes any sense is that the the little turbo has a big a/r wich spools it slow and the big one has a little a/r wich spools it fast but thats all i know. i asked this ? about a/r in the original post and have had no information on it