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My car (3.4L, 10:1, e85, qsv), did 960whp/970wtq with the 6766, and 1115/1100 (iirc) with the 7275 (no other changes but turbo swap).
 

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Yea, thinking I'll stick to the 6766 and switch to the divided housing. After speaking to several friends that experienced main cap failures with turbos bigger than the 6766, I don't want to risk it. I do have a built motor, but I didn't use billet mains. I think the QSV will give me the more broad power curve I am after.

Steve K.
 

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Yea, thinking I'll stick to the 6766 and switch to the divided housing. After speaking to several friends that experienced main cap failures with turbos bigger than the 6766, I don't want to risk it. I do have a built motor, but I didn't use billet mains. I think the QSV will give me the more broad power curve I am after.

Steve K.
Wouldn't the qsv having the tq come on earlier still cause issues to the main caps? That's the main reason I'm going with billet main caps as I want to make as much tq as early as possible.
 

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Will a stud girdle hold the early torque?
 

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My car (3.4L, 10:1, e85, qsv), did 960whp/970wtq with the 6766, and 1115/1100 (iirc) with the 7275 (no other changes but turbo swap).
Did you seriously make 1100wtq on a 7275? DAMN...

Yea, thinking I'll stick to the 6766 and switch to the divided housing. After speaking to several friends that experienced main cap failures with turbos bigger than the 6766, I don't want to risk it. I do have a built motor, but I didn't use billet mains. I think the QSV will give me the more broad power curve I am after.

Steve K.
Steve, i also have that fear to crack a main cap due to low end tq. I thought it was worse when you have a smaller turbo and better when its bigger. Isn't that the case?

Ryan
 

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Wouldn't the qsv having the tq come on earlier still cause issues to the main caps? That's the main reason I'm going with billet main caps as I want to make as much tq as early as possible.
That's a good point. I've heard of issues with a 6266 coming on too early with a QSV and some experiencing issues. The 6766 is a little lazier.

Steve K.
 

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Did you seriously make 1100wtq on a 7275? DAMN...


Ryan

Ryan, notice I said "iirc". I know it was in that neighborhood. I remember remarking at the time that although tq wasn't greater than hp as with the 67, it was very close. and the hp was 1115 for sure.

it also made 1005 ft-lbs with the 86, and that was probably 1500-2k rpm higher.
 

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Discussion Starter #188
Wouldn't the qsv having the tq come on earlier still cause issues to the main caps? That's the main reason I'm going with billet main caps as I want to make as much tq as early as possible.
If you're going to build something with killer torque (torque monster kit, QSV, ethanol, stroker and/or high compression, etc.) and plan on being hard on it, billet main caps are a good choice.

For most everyone else, the QSV doesn't create a prerequisite for billet main caps. Think of it as running one size smaller turbo than you're really running (that's a little bit unfair because it also tweaks the curve as well but you get the idea). Tuning also becomes very important in this aspect as well.

That's a good point. I've heard of issues with a 6266 coming on too early with a QSV and some experiencing issues. The 6766 is a little lazier.

Steve K.
I've only seen this in extreme cases where the driver had limited "self-control" with all of the added torque. This is true for any small turbo, high-torque setups though. It's a standard discussion I have with every car that leaves the shop especially on a stock motor.

Ryan, notice I said "iirc". I know it was in that neighborhood. I remember remarking at the time that although tq wasn't greater than hp as with the 67, it was very close. and the hp was 1115 for sure.

it also made 1005 ft-lbs with the 86, and that was probably 1500-2k rpm higher.
Yes! 1100whp GT42-7275 with the Bubba G-Force! That was one of my favorite iterations of your car for sure. Well, that and the 6766/3.4L/Nitrous/V160 :rockon:
 

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... Yes! 1100whp GT42-7275 with the Bubba G-Force! That was one of my favorite iterations of your car for sure. Well, that and the 6766/3.4L/Nitrous/V160 :rockon:
Lol at "Bubba GForce". good times brother!
 

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Can't believe it's been 4 years. Most of those Supras have bone through several builds since then lol.

Steve
 

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Awesome memories. :bigthumb:
 
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