FordNut
Contributing Member
If you've been into racing, turbos, superchargers so long then why do you keep comparing boost/psi between SC and turbos as if they're the same.
CAUSE THEIR NOT.
different size turbo/sc push different amounts of air, So by you saying a turbo as the same psi as a supercharger would make more power is talking out your
If I am running a DSM T25 at 6psi on my MM and your running a Kenbell SC at 6psi on your MM I can guarantee you that your SC MM is going to make more power than my T25 MM at 6psi. Even if I was were to run a dual T25 setups (Twin turbo) I wouldn't make the same HP as you, Well maybe just about but the same... But that would be cutting it close.
It's all about CFM's and turbo/SC diameter..
lets run this one more time just in case.
If I had a Turbonetics T3/T4 AR.63 at 6psi and a Turbonetics T3/T4 AR.48 at 6psi the out come would be the AR.63 would push more CFM's at 6psi then the AR.48.
So before you come out here shaking your head and trying to prove me wrong you should consider the facts not your logic.
Nonsense...
FordNut
Contributing Member
Did you really say that?
juno
Senior Member
Brandon,
We are talking marauders here. Why would anyone put a small tc on a v-8 that pushes so much air with these heads? Or anything that KB makes twin screw for? The T25 is barely efficient up to the stock chp on a marauder. It might be fine on my svt focus, though I would not use one with an internal waste gate.
It would be like putting a tiny sc on a MM. Very inefficient.
About the smallest tc you would want is around a 57mm. Something with at least 600 chp efficiency.
Why would someone compare a tc and a sc that are not rated for about the same hp/cfm?
A tc is a centrifugal air pump. Working in a similar loop, (same sized piping on air and exhaust, same heads, same compression ratio, etc) the boost/power ratio will be about the same for different size turbo's with similar A/R's. Yes, the smaller one will spin up faster, but on the other end you will see similar boost/power ratio's until you hit the inefficiencies of the smaller turbo. It will then die off, slower then an eaton or any pd blower, but die off nonetheless. The larger tc will spin up slower but be able to develop more boost and remain efficient longer. Of course they won't be exact, but they will be similar if the sizes are such they are both in an efficient range at the same time.
So a 57 mm on an MM may only be able to reach 12-13 psi or so efficiently while my 66 mm may reach 15 or 16 and Todd's 76 mm may get into the mid 20's efficiently. But he does not have a stock motor/heads so the power/boost ratios would look quite different. His higher flowing heads would require less boost to make the same hp. But the 57 and 66 mm will at some point in their ranges have similar boost/power ratios when the 66 is spun up and before the 57 dies off.
Some belt driven blowers use 70-100 (or more) chp to make 450 to the wheels. You have to take that into account when looking at the limits of the rotating assembly, fuel etc.
If you were to compare an eaton and a tc with similar max air flow rates on stock mm's the eaton would need a higher boost level to achieve the same rwhp at the top of their efficient range.
We are talking marauders here. Why would anyone put a small tc on a v-8 that pushes so much air with these heads? Or anything that KB makes twin screw for? The T25 is barely efficient up to the stock chp on a marauder. It might be fine on my svt focus, though I would not use one with an internal waste gate.
It would be like putting a tiny sc on a MM. Very inefficient.
About the smallest tc you would want is around a 57mm. Something with at least 600 chp efficiency.
Why would someone compare a tc and a sc that are not rated for about the same hp/cfm?
A tc is a centrifugal air pump. Working in a similar loop, (same sized piping on air and exhaust, same heads, same compression ratio, etc) the boost/power ratio will be about the same for different size turbo's with similar A/R's. Yes, the smaller one will spin up faster, but on the other end you will see similar boost/power ratio's until you hit the inefficiencies of the smaller turbo. It will then die off, slower then an eaton or any pd blower, but die off nonetheless. The larger tc will spin up slower but be able to develop more boost and remain efficient longer. Of course they won't be exact, but they will be similar if the sizes are such they are both in an efficient range at the same time.
So a 57 mm on an MM may only be able to reach 12-13 psi or so efficiently while my 66 mm may reach 15 or 16 and Todd's 76 mm may get into the mid 20's efficiently. But he does not have a stock motor/heads so the power/boost ratios would look quite different. His higher flowing heads would require less boost to make the same hp. But the 57 and 66 mm will at some point in their ranges have similar boost/power ratios when the 66 is spun up and before the 57 dies off.
Some belt driven blowers use 70-100 (or more) chp to make 450 to the wheels. You have to take that into account when looking at the limits of the rotating assembly, fuel etc.
If you were to compare an eaton and a tc with similar max air flow rates on stock mm's the eaton would need a higher boost level to achieve the same rwhp at the top of their efficient range.
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Todd
Senior Member
If you've been into racing, turbos, superchargers so long then why do you keep comparing boost/psi between SC and turbos as if they're the same.
CAUSE THEIR NOT.
different size turbo/sc push different amounts of air, So by you saying a turbo as the same psi as a supercharger would make more power is talking out your
If I am running a DSM T25 at 6psi on my MM and your running a Kenbell SC at 6psi on your MM I can guarantee you that your SC MM is going to make more power than my T25 MM at 6psi. Even if I was were to run a dual T25 setups (Twin turbo) I wouldn't make the same HP as you, Well maybe just about but the same... But that would be cutting it close.
It's all about CFM's and turbo/SC diameter..
lets run this one more time just in case.
If I had a Turbonetics T3/T4 AR.63 at 6psi and a Turbonetics T3/T4 AR.48 at 6psi the out come would be the AR.63 would push more CFM's at 6psi then the AR.48.
So before you come out here shaking your head and trying to prove me wrong you should consider the facts not your logic.
Boost and CFM are two totally different things. CFM is flow, pure and simple. Boost is the inability of your engine combo to process the cfm it has incoming. Big heads, valves, exhaust, displacement, cam profile will affect how much your engine can process.
I think the biggest thing to consider is efficiency which means heat generation. 6psi on one poweradder and 6psi on another poweradder are not exactly created equal IF, and ONLY IF the IAT is high on one because the unit is inefficient and causing more heat than the other to make that 6psi.
In your example, without looking at the compressor map of the turbo and the efficiency of the Kenne Bell, I would guess the Kenne Bell may have a lower IAT since it would be twiddling its thumbs at 6psi. That may mean more power. But if you swap out the little T25 you used in your example with something like my turbo (see my signature below), I probably have a lower IAT and thus potentially more power.
Also, if they are pretty equally matched, the engine will have to work less to make it on the turbo, injector duty cycle should be less, and it leaves room for more power on the turbo safer if you up the output (thus more boost).
By the way, A/R relates to the exhaust side of the turbo, not the compressor side. It determines the speed the compressor spins at a given engine exhaust flow/volume. It has nothing to do with compressor cfm at a given boost level.
You may have been thinking of the Compressor Wheel Trim or Compressor Wheel Size which would affect overall cfm at a given turbo rpm.
Joe Walsh
STILL N/A
I was wondering when someone would point out that psi/boost is merely a measure of the engine's intake "backpressure".
Change the cams, port the heads, put on a better intake manifold and the same SC combo will now show less boost yet make equal or more HP.
RR|Suki
The Original Paxton
yep, when I did my exhaust I dropped 2psi and gained almost 80hp :burnout:
babbage
Super Touring
ImpalaSlayer
...
they must have been that all mighty COBRA SHORTIES! :bows:
all hail the shorties! :bows:
The problem with a rear mounted turbo is you are giving up most of what makes Turbos so wonderful. The heat energy drives the turbine and provides all that 'free' compressor power while increasing the volumetric efficiency of the engine. The crankshaft doesn't have to transfer 80 HP of compressor power through the rods, pistons, and crankshaft. And when the turbo isn't needed, there is no efficiency penalty in the 'naturally aspirated' mode.
But turbos placed near the engine require headers be custom-fabricated for the Marauder. This is engineering a turbo kit. AFAIK, nobody has done this yet.
We need turbo headers for the Marauder.
But turbos placed near the engine require headers be custom-fabricated for the Marauder. This is engineering a turbo kit. AFAIK, nobody has done this yet.
We need turbo headers for the Marauder.
FordNut
Contributing Member
It has been done, but it's a custom setup and not a kit.
juno
Senior Member
I'll sell you mine when I am done with them.
I assume that was a joke. Did you fabricate them yourself? Are the turbos mounted up front? Any trouble routing the exhaust from the turbo back to the cats?
Any pics of the setup?
Zack
Turbo Marauder
I wonder what the chances of getting the specs/drawings/dimensions from the defunct PTK would be?
Fabbing a set would be much easier given a good starting point. Just buy some 321 SS (or 625 Inconel, my favorite!) and start welding.
MrBluGruv
That GM guy....
PTK was actually based near where I live, if you watch the video of the PTK marauder on youtube you can see in a few fly-by shots a mall that's nearby.
I actually met a gentlemen at a local car meet that said he knew the guy(or one of the guys) that was involved with fabbing the PTK turbo kit for the Marauder and knew where he was working at now. At the time I didn't think to ask him where that was, but when I ran into him another time at the same meet I asked him about it and he said he had no clue what I was talking about. Needless to say, I was not amused.
I actually met a gentlemen at a local car meet that said he knew the guy(or one of the guys) that was involved with fabbing the PTK turbo kit for the Marauder and knew where he was working at now. At the time I didn't think to ask him where that was, but when I ran into him another time at the same meet I asked him about it and he said he had no clue what I was talking about. Needless to say, I was not amused.
juno
Senior Member
The majority of turbo folks prefer mild steel with ceramic coating.
You can ask around the web to find Dalton or perhaps pm Todd. He may know where to locate him. Maybe you can get Dalton to help you.
Or you can buy Todd's car!!!
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ntd
snow :(
PM kariamack he had all the PTK hotside pipeing he was looking to sell some time ago.
Philosophic differences, I suppose. I can appreciate cheap. But given the amount of labor involved, I would rather spend some money on high-temperature piping that won't rot from the inside out. Time is money too, and I value reliability very highly. That is why I used 321 SS for my twin turbo boat headers.
I don't suppose with a passenger car you would be able to take a peek at the headers under load. On my boat, I have glanced back at the engine (briefly) to see the headers glowing orange!