What turbo size are some of ya running
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Originally Posted by F8L Z71
The STS truck base kit comes with a T60.
The F-body kit uses a 60-1
The 6.0L SS Silverado uses a GT67
The F-body kit uses a 60-1
The 6.0L SS Silverado uses a GT67
I'm a little surprised the Silverado SS is quoted with the GT67, while the LQ4 falls under the T60.
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Originally Posted by FarmTruc
You can go one size larger on the turbo if you install a converter, having a stall makes a world of difference!!
I run the GT67 .81 ar and having the stall makes for no lag at all. I literally boosts as soon as I downshift or make the stall unlock.
I run the GT67 .81 ar and having the stall makes for no lag at all. I literally boosts as soon as I downshift or make the stall unlock.
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Originally Posted by marc_w
Do you happen to know the differences, or pro's and con's between those?
I'm a little surprised the Silverado SS is quoted with the GT67, while the LQ4 falls under the T60.
I'm a little surprised the Silverado SS is quoted with the GT67, while the LQ4 falls under the T60.
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Originally Posted by Silverado_L31
what is AR on a turbo? i hear everyone talk about it, but what is it?
The exhaust and compressor housings on turbo chargers use a "scroll" design. For example, the exhaust housing's scroll is where the exhaust gasses enter the housing and are directed at the turbine. It's basically a smooth, tubular chamber that surrounds the turbine with a slot all the way around that acts as a nozzle to direct the exhaust gasses at the turbine. It's called a scroll because it slowly gets smaller in diameter as a goes around the turbine. This pressurizes the gasses, forcing them out of the slot/nozzle at a fast rate. In turbo-terms, the scroll is measured by the cross-sectional area of the scroll's "tube" (A) and the distance from the center of the "tube" to the turbine shaft (R). The values by themselves are not meaningful to the user and for the most part, R does not change much for different housings, but by dividing R into A, you get the A/R ratio. So, the A/R ratio of the exhaust housing refers to the size and shape of the scroll that is cast into the housing. It basically determines how restrictive the housing will be, versus how quickly the turbine will spin up. A lower A/R ratio (smaller scroll area, A) results in a more restrictive housing. This restriction speeds up the exhaust gasses and increases the amount that the gasses will expand. It's the speed and expansion of the gasses that causes the turbine to spin. So with a low A/R ratio, the turbine will spin up quicker, but as engine output and rpms increase, the restriction of the housing begins to build up too much back pressure on the engine, which reduces performance. A good rule of thumb for when there is too much back pressure is when the pressure in the exhaust manifold is more the half of the pressure in the cylinder. So basically, a larger A/R ratio will improve your engine's top end, while losing some mid range power and increasing turbo lag. A smaller A/R ratio will help the bottom and mid-range, but may effect the top end.
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Originally Posted by marc_w
Do you happen to know the differences, or pro's and con's between those?
I'm a little surprised the Silverado SS is quoted with the GT67, while the LQ4 falls under the T60.
I'm a little surprised the Silverado SS is quoted with the GT67, while the LQ4 falls under the T60.
The pros and cons will all depends on the individual and his/her needs. On a small stock 4.8L the 60-1 will spool up quickly enough to satisfy most people and probably do ok on the top end. Now on a 6.0L that same 60-1 will spool VERY fast but the top end won't be anywhere near what a GT67 would put out.. So basically is is just a matter of sizing the turbo to make the power you want, where you want it in the rpm band, and balancing spool time. It is a fine line to make max hp yet still spool up fast. On small displacment motors like the Supra you HAVE to accept lag to make really high HP. On the STS kits you will have to sacrifice some lag just like a Supra would due to thermal loss once you start getting into the big turbos with larger A/Rs. Reason being is that once you start getting into the .96-1.00 A/R you are starting work like a normal front mount turbo would and without the thermal energy it just wont spool as fast. That's what happened to me in my truck.
Now it is usually a matter of looking at compressor maps and doing come CFM calculations to figure out which turbo is right for your combo. With our rear mount kits there are no reliable compressor maps so you have to rely on pioneers out there who are trying different turbos and see what worked for them.
IMO a built 4.8 or 5.3 that wants minimum spool time but also wants good power the GT35 would kick butt. The GT67 would lag too much. If you are like me and don't mind some lag in trade for excellent top end then the GT67 rocked.
In a stock vehicle for mostly daily driving and the occational tire frying fest the 60-1 would more than suffice and have great drivability and excellent throttle response.
This is all opnion so if someone dissagrees I wont take offense.
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Originally Posted by F8L Z71
The pros and cons will all depends on the individual and his/her needs. On a small stock 4.8L the 60-1 will spool up quickly enough to satisfy most people and probably do ok on the top end. Now on a 6.0L that same 60-1 will spool VERY fast but the top end won't be anywhere near what a GT67 would put out.. So basically is is just a matter of sizing the turbo to make the power you want, where you want it in the rpm band, and balancing spool time. It is a fine line to make max hp yet still spool up fast. On small displacment motors like the Supra you HAVE to accept lag to make really high HP. On the STS kits you will have to sacrifice some lag just like a Supra would due to thermal loss once you start getting into the big turbos with larger A/Rs. Reason being is that once you start getting into the .96-1.00 A/R you are starting work like a normal front mount turbo would and without the thermal energy it just wont spool as fast. That's what happened to me in my truck.
Now it is usually a matter of looking at compressor maps and doing come CFM calculations to figure out which turbo is right for your combo. With our rear mount kits there are no reliable compressor maps so you have to rely on pioneers out there who are trying different turbos and see what worked for them.
IMO a built 4.8 or 5.3 that wants minimum spool time but also wants good power the GT35 would kick butt. The GT67 would lag too much. If you are like me and don't mind some lag in trade for excellent top end then the GT67 rocked.
In a stock vehicle for mostly daily driving and the occational tire frying fest the 60-1 would more than suffice and have great drivability and excellent throttle response.
This is all opnion so if someone dissagrees I wont take offense.
Now it is usually a matter of looking at compressor maps and doing come CFM calculations to figure out which turbo is right for your combo. With our rear mount kits there are no reliable compressor maps so you have to rely on pioneers out there who are trying different turbos and see what worked for them.
IMO a built 4.8 or 5.3 that wants minimum spool time but also wants good power the GT35 would kick butt. The GT67 would lag too much. If you are like me and don't mind some lag in trade for excellent top end then the GT67 rocked.
In a stock vehicle for mostly daily driving and the occational tire frying fest the 60-1 would more than suffice and have great drivability and excellent throttle response.
This is all opnion so if someone dissagrees I wont take offense.
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Originally Posted by LTNKLR01
I agree with you 100%. I was going to go with the smaller gt35 or 60 but oppted for the bigger gt67. I figured that witht the built motor and the right cam that i will be ok and not have way to much lag. Guess we will just have to wait and see
I thought about you when I wrote that but I consider you a special case. You're going beyond what most people would with that 4.8L of yours AND you have an excellent tuner to work with.