Triple turbo choice
- Thread starter Dallas S
- Start date
Scott at SDP did basically all of it the first time around. Since then I have taught myself a lot more of the details of turbo tech (I was a jet propulsion aero major in school years back so have a good baseline understanding of the theory) I have been throwing some ideas around to get more power and keep the same DD characteristics of a stock turbo truck. Really I’m limited by funding and my stock cut and coated pistons right now. If you really don’t have a good understanding of how turbo systems work it really is worth the money to talk to someone who really knows. I still talk to Scott before I mess anything up.
Your right... Out of curiousity what's the biggest set of triples anyone has done ?
While I take a break from packing up my house...
If you guys see something wrong please call me out on it (I'm sure some of you will!)
This is basic, but figure it might help some of the new guys
first some terms
mass flow rate (lb/min) the physical weight or amount of air flowing in the system. This is irrelevant of temp or pressure.
Corrected mass flow( http://en.wikipedia.org/wiki/Corrected_flow ) is mass flow "corrected" for pressure and temp. This number will change in a closed system, raise the temp and it goes up. Raise the pressure it is under and it will go down.
Primary turbo(s), atmospheric, low pressure etc.
Secondary turbo, second stage of compression, high pressure etc.
CR-compression ratio, or how many times a compressor reduces the volume of air
MAP-a graph of a compressor (or turbine) with CR on the Y axis and usually corrected mass flow on the X axis
CFM-like corrected mass flow, it changes based on CR and temp with the actual mass low
to continue on
A few things you need to figure out before you start looking at turbos.
How much air do I need?
What is the most restrictive part of the system that I have to flow
Where do I want the kit to be best at.
You can figure the air you need based on lb/min, this is the number of air molecules that will interact with the amount of fuel you are burning. Of course you want more air than you need, this helps with a cleaner burn since you will never have a near perfect burn. I am still weak on knowledge of good ways to come up with this number for our engines but I'm sure someone can chime in.
What CR you need. On a built engine, the most restrictive part should be the heads. Heads flow in corrected mass flow, the more compressed and cooler the air the better they flow. Cooler air also allows for more temp change in the chamber thus allowing more fuel to be added before reacting critical temps.
A few things about compressors, you can only get so much CR out of a single stage wheel. And as you get towards the upper limit you take it out of its most efficient range and start making more heat. Anytime you compress air you heat it, even in a perfect world. Adding heat makes everything flow worse so while you see more PSI, you are not seeing more mass flow, but more corrected mass flow (heated air wants to take up more space). Bigger chargers really don't give you much higher CRs, just more mass flow. So if you are going to run a really large single charger, you better have a very free flowing setup and a really good IC (prob air to water). That is where the 2 stages of compression come in. A compressor does not care about "boost PSI" just corrected mass flow and CR. So after getting the air out of the primary turbo, the secondary stage further compresses it giving you a CR much larger than any single could do and well within both turbo's MAPs.
Now the other part of 2 stages is of course the second stage is going to be a smaller compressor, and this allows for much better DD ability. This is where IMHO the reason of the kit comes in, if you want it only for racing then you want to size it so both turbos are right in the sweet spot of the MAP at max fueling. If you want it for a DD most of the time, then you cheat the secondary a little smaller (but not too much) so it drives better.
TBC later
If you guys see something wrong please call me out on it (I'm sure some of you will!)
This is basic, but figure it might help some of the new guys
first some terms
mass flow rate (lb/min) the physical weight or amount of air flowing in the system. This is irrelevant of temp or pressure.
Corrected mass flow( http://en.wikipedia.org/wiki/Corrected_flow ) is mass flow "corrected" for pressure and temp. This number will change in a closed system, raise the temp and it goes up. Raise the pressure it is under and it will go down.
Primary turbo(s), atmospheric, low pressure etc.
Secondary turbo, second stage of compression, high pressure etc.
CR-compression ratio, or how many times a compressor reduces the volume of air
MAP-a graph of a compressor (or turbine) with CR on the Y axis and usually corrected mass flow on the X axis
CFM-like corrected mass flow, it changes based on CR and temp with the actual mass low
to continue on
A few things you need to figure out before you start looking at turbos.
How much air do I need?
What is the most restrictive part of the system that I have to flow
Where do I want the kit to be best at.
You can figure the air you need based on lb/min, this is the number of air molecules that will interact with the amount of fuel you are burning. Of course you want more air than you need, this helps with a cleaner burn since you will never have a near perfect burn. I am still weak on knowledge of good ways to come up with this number for our engines but I'm sure someone can chime in.
What CR you need. On a built engine, the most restrictive part should be the heads. Heads flow in corrected mass flow, the more compressed and cooler the air the better they flow. Cooler air also allows for more temp change in the chamber thus allowing more fuel to be added before reacting critical temps.
A few things about compressors, you can only get so much CR out of a single stage wheel. And as you get towards the upper limit you take it out of its most efficient range and start making more heat. Anytime you compress air you heat it, even in a perfect world. Adding heat makes everything flow worse so while you see more PSI, you are not seeing more mass flow, but more corrected mass flow (heated air wants to take up more space). Bigger chargers really don't give you much higher CRs, just more mass flow. So if you are going to run a really large single charger, you better have a very free flowing setup and a really good IC (prob air to water). That is where the 2 stages of compression come in. A compressor does not care about "boost PSI" just corrected mass flow and CR. So after getting the air out of the primary turbo, the secondary stage further compresses it giving you a CR much larger than any single could do and well within both turbo's MAPs.
Now the other part of 2 stages is of course the second stage is going to be a smaller compressor, and this allows for much better DD ability. This is where IMHO the reason of the kit comes in, if you want it only for racing then you want to size it so both turbos are right in the sweet spot of the MAP at max fueling. If you want it for a DD most of the time, then you cheat the secondary a little smaller (but not too much) so it drives better.
TBC later
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Delete the stock fuel filter, move the overflow tank and only run one batt and you could jam a dead body on the passenger side engine compartment
All of this to do what a good quality single charger (set up properly) can do......
I just don't understand
I just don't understand
jason Wherli (quadracer) had 3 s483s i believe,he just sold them.Wonder if he's going bigger
Someone please tell me a single charger that can make 1000hp, still dd and pull trailers. Everyone is sayin there all confused why people do 2-3 chargers when 1 can do same. I dont know of any, and no nitrous to help light it either.
Tripples and twins are more linaer in power singles are hard hitting have some lag down low traditionaly not always,I wanted twins for pulling my big snowmobile trailer i didnt want a big single to go from a lag to lighting hard when i was on snow or ice..........and well.............ok i wanted it to fly :rofl:
I would like to know how much air that gtx45 and 2 s480 flow. It has to be a lot more than a precision 106.
I wont say it will make a grand , it will get 8 to 900hp , but I think with right tuning and converter , a gtx4202 can be daily driven and pull light loads. I drove mine for over a year and pulled nothing more than a car trailer with it , it wasn't all that bad . The charger just naturally lights quick .........
So basically it might get most the way there hp wise and possibly dd and wont tow certain things, but yet people still say singles will do what twins or triples will. I guess im confused on the confusion here.:roflmao:
I hear what your sayin but seems to me the reason for twins or triples are, easier power, dd and tow anything. I am liking this thread on options cause i to am goin to.be lookin for a huge set of twins or triples in the next year or so.
I'm running about 850 RWHP right now but I am very fuel limited-I have the air for 1000HP. My 650 HP street tune has less smoke than most 450 on stock turbo tunes. I DD the truck all the time in bad weather, and I'm about to take the truck loaded out at 23K 1500 miles and not think about it, you can say I'm happy with my triples! :roflmao: