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In the context of the original post I'd say my statement stands But sure, once you have to crack the block and replace internals all's in the same ballpark.
 

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Go with a basic CX racing turbo kit on stock internals and get it running on 8lbs of boost reliably.

Then, if you want to make a monster 400hp+ car, upgrade your internals.
 

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I agree to a point. Even with factory turbo cars, they have a limit they can get to before you have to rebuild the engine to handle more power. In the end, it comes to what car you enjoy driving and how much power you want to push. If you are pushing 300whp to 350whp.....most factory turbo cars can push that easily where as you are spending 10k+ for an IS300 to push that. If you are going for 600+whp....you'll be spending roughly the same for both factory and IS to get that power. Given that, there are some factory cars that can run up to 700+whp without rebuilding but those become ticking timebombs.
not mention its a 4 door sports car so you can have a car and fit more people in it. Plus its a 2jz which can be almost unlimited power and still be a reliable car just making slight internal changes as opposed to maybe another factory engine that can get that much power but would be a nightmare if you want to daily drive as it would keep breaking.
 

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not mention its a 4 door sports car so you can have a car and fit more people in it. Plus its a 2jz which can be almost unlimited power and still be a reliable car just making slight internal changes as opposed to maybe another factory engine that can get that much power but would be a nightmare if you want to daily drive as it would keep breaking.
Anything pass a benchmark what the factory setting for any car makes it more unreliable. A 2jz can handle big power with upgraded internals is great but now you have to change the fuel system, standalone ecu, cooling, drivetrain, turbo kits to support that power. We are talking about changing the a lot for big power, not just engine. Where as 350whp is easily attain with tuning on most factory turbo cars.
 

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A huge component of engine reliability is the control system. Powertrain engineers figured out that boost makes big power a long time ago. There have been 3 generations of factory built turbocharged cars, but only the latest has been a big success. That is not because crankshafts and connecting rods were not sufficient in the 1960s or 1980s. It's because they lacked a control system that could keep everything running "just so" regardless of ambient temp, coolant temp, oil temp, fuel octane, driver habits, etc. The 1960s turbo cars with carburetor and distributor were notoriously unreliable; the EFI 1980s turbo cars were a lot better at keeping the engine inside it's safe operating envelope; but those EFI system still lacked a lot of inputs and feedback from the engine to prevent meltdowns.

The point I'm really trying to make is reliability of your build will very largely come down to your control system - and how well it's calibrated. Choose good hardware and find a tuner/calibrator that really knows what they're doing.
 

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Anything pass a benchmark what the factory setting for any car makes it more unreliable. A 2jz can handle big power with upgraded internals is great but now you have to change the fuel system, standalone ecu, cooling, drivetrain, turbo kits to support that power. We are talking about changing the a lot for big power, not just engine. Where as 350whp is easily attain with tuning on most factory turbo cars.
Well yeah of course. But if you think about how much of a 650hp or so car would cost from the factory. For what you're getting your still gonna get a better deal and get something fairly reliable for what it is after making all those changes. not to mention that it may have 650hp and might not be as fun as 650hp IS. All I'm saying for what it is its not a bad deal.
 

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All in all, just don't cheap out on parts to save money. To obtain reliability and also be fast, expect to spend a lot of money.
 

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All in all, just don't cheap out on parts to save money. To obtain reliability and also be fast, expect to spend a lot of money.
15k-20k. Not terrible in my book from what I been digging. Probably make even more than 600hp if you want it. I'm only looking at 550-600hp for myself on pump. There's probably multiple ways to do it. You could also buy someone's built but that could be risky.
 

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All in all, just don't cheap out on parts to save money. To obtain reliability and also be fast, expect to spend a lot of money.
at first I was going to get a corvette and for that power it would been at least 70k. That's why I started looking into turbo the IS.
 

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A hobby built $15-20k turbo is300 and a factory built $70+k corvette are comparable in peak power output only, if at all.

Reliability, street legality, emissions, squared-awayness, residual value, top speed, handling, traction control, yaw control, braking, etc etc is no comparison.

Even then, I just don't see how you can compare them on power alone:

One has an engine that you or perhaps "your guy" put together. The other is built by the best-of-the-best technicians from a company that builds many millions of LS based engines per year.

One has a calibration that you or perhaps "your guy" spent, at best, a few weeks on the road and a few hours on the dyno creating. The other has a calibration based on tens of thousands of dyno hours by dozens of powertrain engineers, in a facility that cost tens of millions of dollars so that any condition the engine might ever encounter can be replicated and tested, and accounted for. Additionally, the calibration file in your ecuMaster, ProEFI, Link (or whatever) contains a couple megabytes of data. The OEM one in the corvette has 250MB or more.

Which one of these do you think will control the engine with greater refinement and precision? Which one is more likely to diagnose the sensors to ensure they are providing trustworthy feedback to the ecu so that it can take appropriate action if something goes awry? Which one of these is more likely to pop during a top speed run in 110º weather? Which one is more likely to start up perfectly on E85 on a cold morning?

Don't get me wrong, if you like IS300s and would be happy with one if it had some stiffer springs and dampers and some more power - build one up. Speaking from experience, to build up a nice, straight, clean one with quality parts, you'll certainly be in it for more than $20k, but what you create is simply not comparable to a late model, factory built Corvette.
 

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A hobby built $15-20k turbo is300 and a factory built $70+k corvette are comparable in peak power output only, if at all.

Reliability, street legality, emissions, squared-awayness, residual value, top speed, handling, traction control, yaw control, braking, etc etc is no comparison.

Even then, I just don't see how you can compare them on power alone:

One has an engine that you or perhaps "your guy" put together. The other is built by the best-of-the-best technicians from a company that builds many millions of LS based engines per year.

One has a calibration that you or perhaps "your guy" spent, at best, a few weeks on the road and a few hours on the dyno creating. The other has a calibration based on tens of thousands of dyno hours by dozens of powertrain engineers, in a facility that cost tens of millions of dollars so that any condition the engine might ever encounter can be replicated and tested, and accounted for. Additionally, the calibration file in your ecuMaster, ProEFI, Link (or whatever) contains a couple megabytes of data. The OEM one in the corvette has 250MB or more.

Which one of these do you think will control the engine with greater refinement and precision? Which one is more likely to diagnose the sensors to ensure they are providing trustworthy feedback to the ecu so that it can take appropriate action if something goes awry? Which one of these is more likely to pop during a top speed run in 110º weather? Which one is more likely to start up perfectly on E85 on a cold morning?

Don't get me wrong, if you like IS300s and would be happy with one if it had some stiffer springs and dampers and some more power - build one up. Speaking from experience, to build up a nice, straight, clean one with quality parts, you'll certainly be in it for more than $20k, but what you create is simply not comparable to a late model, factory built Corvette.
I mean It depends on the individual too. Maybe a person doesn't want all that and just want the power or doesn't find its worth 70k for all that. I mean if you want to get THAT specific than that's different topic. I'm pretty content with my IS I just want to be zippier. And really modern cars nowadays ehh they ain't what they used to be I'll just put it like that. Everything you mention yeah traction control would be a little better but everything else its not really a big deal to me. Maybe handling but is300 handling its pretty good for what it is. Plus corvette doesn't have 4 doors so I can't fit friends for real comfortably and still have a fairly light fun car. Not to mention I've seen "newer" cars have more problems than an 20 year old or even modified is300. Just because it's new and best of the best technicians (maybe) doesn't always mean its gonna be better for you. Specially nowadays the way companies cut corners to save money. You're not going to care about all that new stuff if gives you a headache having to fix it all the time. There's pros and cons to everything.
 

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A hobby built $15-20k turbo is300 and a factory built $70+k corvette are comparable in peak power output only, if at all.

Reliability, street legality, emissions, squared-awayness, residual value, top speed, handling, traction control, yaw control, braking, etc etc is no comparison.

Even then, I just don't see how you can compare them on power alone:

One has an engine that you or perhaps "your guy" put together. The other is built by the best-of-the-best technicians from a company that builds many millions of LS based engines per year.

One has a calibration that you or perhaps "your guy" spent, at best, a few weeks on the road and a few hours on the dyno creating. The other has a calibration based on tens of thousands of dyno hours by dozens of powertrain engineers, in a facility that cost tens of millions of dollars so that any condition the engine might ever encounter can be replicated and tested, and accounted for. Additionally, the calibration file in your ecuMaster, ProEFI, Link (or whatever) contains a couple megabytes of data. The OEM one in the corvette has 250MB or more.

Which one of these do you think will control the engine with greater refinement and precision? Which one is more likely to diagnose the sensors to ensure they are providing trustworthy feedback to the ecu so that it can take appropriate action if something goes awry? Which one of these is more likely to pop during a top speed run in 110º weather? Which one is more likely to start up perfectly on E85 on a cold morning?

Don't get me wrong, if you like IS300s and would be happy with one if it had some stiffer springs and dampers and some more power - build one up. Speaking from experience, to build up a nice, straight, clean one with quality parts, you'll certainly be in it for more than $20k, but what you create is simply not comparable to a late model, factory built Corvette.
Plus who's really going to care about all that if you end up smoking one in a race. LOL.
 

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Plus who's really going to care about all that if you end up smoking one in a race. LOL.
The Z06 we're discussing is an extremely potent machine. It has explosive torque from 6.2L with a positive displacement blower, coupled with an excellent coefficient of drag... All up weights of the Z and the is are pretty similar, but the average torque from say, 3krpm to 7000rpm of the blown 6.2L is more than double that of the turbo 3.0L

The Z will easily start from a dig better than a laggy turbo 3.0L, and once at speed, cut through the air much easier.

You'll need (a lot) more than 650hp in an is300 to even hang with a C7 Z06, much less "smoke" it.

Edit to add: My turbo IS is good for 470whp, so prolly about 525hp or so. A buddy has a C6 Z06 with a cam that does 530whp, but on a different dyno. Bottom line is he's got 50whp or so on me, but his car lays the smack down on me so hard that it looks like I'm not even trying. From a dig or a roll. Worse from a roll where he not only has the weight and power advantage, but also the aero.
 

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The Z06 we're discussing is an extremely potent machine. It has explosive torque from 6.2L with a positive displacement blower, coupled with an excellent coefficient of drag... All up weights of the Z and the is are pretty similar, but the average torque from say, 3krpm to 7000rpm of the blown 6.2L is more than double that of the turbo 3.0L

The Z will easily start from a dig better than a laggy turbo 3.0L, and once at speed, cut through the air much easier.

You'll need (a lot) more than 650hp in an is300 to even hang with a C7 Z06, much less "smoke" it.
maybe who knows. It ain't that serious to me anyways. All I'm saying is it ain't worth 70k. Rather build my IS and use the rest of that money to get a lifted truck.
 

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The Z06 we're discussing is an extremely potent machine. It has explosive torque from 6.2L with a positive displacement blower, coupled with an excellent coefficient of drag... All up weights of the Z and the is are pretty similar, but the average torque from say, 3krpm to 7000rpm of the blown 6.2L is more than double that of the turbo 3.0L

The Z will easily start from a dig better than a laggy turbo 3.0L, and once at speed, cut through the air much easier.

You'll need (a lot) more than 650hp in an is300 to even hang with a C7 Z06, much less "smoke" it.
Yeah pretty much If I didn't want a lifted Truck (which is something I've wanted my entire life I just ended up with the IS because family member gave me there's as a first car and I liked how zippy reliable it was) then I'd probably look into getting the Vette. But like I said the cost of keeping one would be up there. Not even including how overpriced insurance would be. LOL. Maybe when I'm an old man we'll see.
 

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Buy a blown vette crate motor and drop it in the IS?

Yeah i know.... :unsure: :p
 
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