Undersizing or Oversizing Your Turbo: An "Honest" Discussion.
12-19-2012, 07:01 PM
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Undersizing or Oversizing Your Turbo: An "Honest" Discussion. I'm stackin' my funds for a build and I have seen numbers that are far above what I would like to achieve and numbers that seem a little bit lower. I am hoping that members such Bill Reid, denmah, stock48 and so on can chime in on their experiences with a description of their setups and dyno sheets.
In my little world, a 5.3 making somewhere in the neighborhood of 475-500whp is enticing, but it seems like a moderately small 62-1 or a larger T76 could both get you there....
I get that the smaller turbo would have to work harder and probably produce more heat in the process, but I have a street truck that will likely see a track once if ever in it's life. I find that there are scattered threads all over this site, but maybe it's time for the experienced to chime in with their findings in a single location.
Guys keep in mind that information about your chosen cam and your car's driving characteristics would make this thread that much more interesting and useful... It would also serve other members well to hear if you chose to change intakes and/or cylinder heads and other parts to attain your goal.
On so many levels this is still one of the greatest enthusiast sites on the net and I feel like it's time to shed some more light on FI LS-engines....
In my little world, a 5.3 making somewhere in the neighborhood of 475-500whp is enticing, but it seems like a moderately small 62-1 or a larger T76 could both get you there....
I get that the smaller turbo would have to work harder and probably produce more heat in the process, but I have a street truck that will likely see a track once if ever in it's life. I find that there are scattered threads all over this site, but maybe it's time for the experienced to chime in with their findings in a single location.
Guys keep in mind that information about your chosen cam and your car's driving characteristics would make this thread that much more interesting and useful... It would also serve other members well to hear if you chose to change intakes and/or cylinder heads and other parts to attain your goal.
On so many levels this is still one of the greatest enthusiast sites on the net and I feel like it's time to shed some more light on FI LS-engines....
12-19-2012, 07:13 PM
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for 500 rwhp dont even touch the engine, just throw a cheap on3 76mm turbo on it or an even cheaper ebay gt45 and be done. really nothing special needed at that power level.
12-19-2012, 07:59 PM
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I appreciate your input as I think many member's suggestions are skewed toward drag race setups where a huge turbo would make more sense, but it's hard to find useful information for a more street oriented guy....
12-19-2012, 08:00 PM
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its not undersized if it does what you want it to do. there is a huge kick right now for giant exhaust turbines, which is great for some.. not great for others who drive their car on the street and dont want a v8 with a supra powerband.
as far as me.. i love my now too small pt7675 with the too small 75mm turbine that spools stupid fast on the 5.3 and can still spit out 900 rwhp (allegedly havnt tried it yet!! lol).
as far as me.. i love my now too small pt7675 with the too small 75mm turbine that spools stupid fast on the 5.3 and can still spit out 900 rwhp (allegedly havnt tried it yet!! lol).
12-19-2012, 08:04 PM
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The one change I was considering was going with the Comp XR259HR or XR265HR (I think the XR265HR has a lower chance of detonating). I just want a bigger kick in the pants when I drop the hammer, but nothing crazy and I am not trying to set any records whatsoever....
I appreciate your input as I think many member's suggestions are skewed toward drag race setups where a huge turbo would make more sense, but it's hard to find useful information for a more street oriented guy....
I appreciate your input as I think many member's suggestions are skewed toward drag race setups where a huge turbo would make more sense, but it's hard to find useful information for a more street oriented guy....
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12-19-2012, 08:09 PM
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I know Bill Reid was running a 60-1 and he said it seemed to choke off at about 5500 rpm so he went to a t66. If I could get away with a 62-1 or a T66 that carried me out to 6000rpm even if it was basically flatlining would be fine too.... I just want that passing power that gets you to 120 before your know it, but not exactly to start a career as a bootleg Mario Andretti on the freeway....
I've seen a couple of 5.0s running 60-1 and 62-1 and getting into the 10's at the track. I understand I am driving a heavier vehicle, but if I could get a good bump with a smaller turbo it would probably work out fine for me.
I also understand what you mean about running too large of a cam. I see some crazy durations on the forums and I have to wonder how much money is being wasted on trying to get decent performance out of bad combinations.
12-19-2012, 08:16 PM
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Let me ask you guys something else....
Here and there you hear stories about guys killing their short blocks with boost, but I am sure these are the kind of guys that dog their cars day in and day out (and/or get too aggressive with the boost ****)...
I do like to drive fast, but I don't do track days or much stoplight racing, I just like responsive car and I figure with conservative boost levels, a good tune and quality gasoline the occasional romp shouldn't leave me motorless, right...?
I honestly can't recall ever pushing my little 5.3 all the way to 6-grand ever.... (5500 maybe). I want the party over by then which is why good sizing (and quick spool up) is important to me... 90-125 I'll fight for the road-after that-it's all yours....
Here and there you hear stories about guys killing their short blocks with boost, but I am sure these are the kind of guys that dog their cars day in and day out (and/or get too aggressive with the boost ****)...
I do like to drive fast, but I don't do track days or much stoplight racing, I just like responsive car and I figure with conservative boost levels, a good tune and quality gasoline the occasional romp shouldn't leave me motorless, right...?
I honestly can't recall ever pushing my little 5.3 all the way to 6-grand ever.... (5500 maybe). I want the party over by then which is why good sizing (and quick spool up) is important to me... 90-125 I'll fight for the road-after that-it's all yours....
12-19-2012, 08:20 PM
#10
How does it run with that turbo...? Where are you spooling up...? (2500 rpm, 3000rpm, 3500rpm...?)
I know Bill Reid was running a 60-1 and he said it seemed to choke off at about 5500 rpm so he went to a t66. If I could get away with a 62-1 or a T66 that carried me out to 6000rpm even if it was basically flatlining would be fine too.... I just want that passing power that gets you to 120 before your know it, but not exactly to start a career as a bootleg Mario Andretti on the freeway....
I've seen a couple of 5.0s running 60-1 and 62-1 and getting into the 10's at the track. I understand I am driving a heavier vehicle, but if I could get a good bump with a smaller turbo it would probably work out fine for me.
I also understand what you mean about running too large of a cam. I see some crazy durations on the forums and I have to wonder how much money is being wasted on trying to get decent performance out of bad combinations.
I know Bill Reid was running a 60-1 and he said it seemed to choke off at about 5500 rpm so he went to a t66. If I could get away with a 62-1 or a T66 that carried me out to 6000rpm even if it was basically flatlining would be fine too.... I just want that passing power that gets you to 120 before your know it, but not exactly to start a career as a bootleg Mario Andretti on the freeway....
I've seen a couple of 5.0s running 60-1 and 62-1 and getting into the 10's at the track. I understand I am driving a heavier vehicle, but if I could get a good bump with a smaller turbo it would probably work out fine for me.
I also understand what you mean about running too large of a cam. I see some crazy durations on the forums and I have to wonder how much money is being wasted on trying to get decent performance out of bad combinations.
12-19-2012, 08:42 PM
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I see what you are saying. Did you change cams or anything...?
12-19-2012, 09:35 PM
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I have a cam with associated mods and an Edelbrock intake with elbow. That's really it for the engine.
Link below to my car:
https://ls1tech.com/forums/multimedi...-ss-today.html
12-19-2012, 10:15 PM
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Are any of you guys using boost controllers are is a standard wastegate good enough.... Frankly I don't hear much about boost controllers on here either, but from most of the dynosheets I see it may not be necessary..
12-19-2012, 10:33 PM
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Im two minutes from raceway park.
I have a cam with associated mods and an Edelbrock intake with elbow. That's really it for the engine.
Link below to my car:
https://ls1tech.com/forums/multimedi...-ss-today.html
I have a cam with associated mods and an Edelbrock intake with elbow. That's really it for the engine.
Link below to my car:
https://ls1tech.com/forums/multimedi...-ss-today.html
12-19-2012, 10:44 PM
#18
If you are building a truck, I recommend you look over on performancetrucks.net, the sister site to ls1tech. Lot of turbo trucks over there.
But like everyone else has said, 500rwhp is not hard and a small turbo will be fine if you are honest with your goals.
But like everyone else has said, 500rwhp is not hard and a small turbo will be fine if you are honest with your goals.
