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Discussion Starter #1
I just bought an automatic '02 IS300 SportCross, and the wheels are already turning in my head for ways to make it faster. I'll be honest, wanting a turbo 2JZ was part of why I got the car.

Now, this is a ways off (I bought the car so I'd have transportation while doing some upgrades on my old Corvette), but I'm trying to scope out the build - I always like to plan everything out for stuff like this well in advance.

My main constraints on the build are:
  • I'm trying to keep it as cheap as possible without regretting my choices. I know from experience this is a dangerous game, but I always like to play.
  • I'd like to avoid permanent, major modifications. I'll swap parts all day long, but the SportCross is pretty rare so I don't want to go rolling fenders, chopping the firewall, etc. I'm okay with "permanent" modifications as long as it wouldn't be too expensive to return it to stock (e.g. modifying a bracket that could be replaced without too much cost or work).
  • Since my other car is a Corvette, I'd like to keep this one as comfortable and driveable as possible. No VB modification for jackhammer shifts, no huge cams giving a crappy idle, etc.
  • I'd like to not have to tear apart the engine or the transmission.
  • I'm not sure if the IS300 is E85-compatible (or if the fuel system needs to be upgraded), but I'd like to keep it on 93 octane for now so I don't have to worry about E85 composition.
I've done a lot of work on my Corvette, so I'm comfortable handling pretty much any work except fabrication or that which would require tools that aren't common and can't be borrowed from the local auto parts store. I'm new to the turbo world, but I'm learning fast (I think - I'm trying at least).

I'm not set on big power. Even 300hp at the crank would be fine for now. That said, I'd like to keep the door open to upgrading eventually.


As I see it, there are several key constraints:
  • The A650E is good for (depending who you ask) anywhere from 300-450hp at the wheels. And some say that hard shifting into 3rd will eventually fail the 3rd gear sprag at any power beyond stock.
  • The rods in the VVTi 2JZ-GE are good for around 400hp at the wheels.
  • The ring lands in the VVTi 2JZ-GE are only safe to around 300hp at the wheels (some people say as much as 350-400hp).
  • The widest wheel you can fit in the rear without modifications is an 8.5", so you're probably looking at a tread width of 255mm. Also, I will be forced to run all-seasons. Without an electronic boost controller to reduce boost in lower gears, this could be tricky. (My Corvette doesn't have traction control, so I have no idea how well traction control would manage things.)
  • A lot of people say not to go over 6psi, but this seems like a pretty useless caution since there's much more to the story than boost pressure. If this rule were followed, I imagine you'd be looking at around 215*(20.7/14.7) = 303hp at the crank.
The weakest link there seems to be the ring lands, so without replacing pistons I'm looking at a max of 300hp at the wheels, which translates to 385hp at the crank assuming 22% drivetrain loss.

What do you guys think? Can I meet my goals with a 300whp build? Would it be manageable with 255s? Dare I try it with the current 215s?
 

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I'd LS swap it before I went down this path.

I've been eyeballing the LFX 60 degree DOHC 3.6 liters used in the manual Caddy CTS's lately. They make decent power, have readily available manuals, can be reflashed and the exhaust is just two square flanges instead of individual runner headers. If they can fit in a Miata, they ought to fit the IS.

Neither path is that cheap but I expect the NA drivetrain would be more reliable.
 

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People here don't really talk in crank horsepower numbers. Going turbo you always sort of lose a bit of a reliability aspect. Unless you are really good. I recommend against boosting the stock GE in general. If you are serious just build an engine on the side with GTE/GE non vvti internals, ARP head studs and some fresh seals and you can feel comfortable boosting. It is covered pretty heavily here. I had a lot of fun with 310 whp and I also had a lot of fun on my stock ecu, 10 psi car.(Not saying I recommend that at all, also never dynoed) All depends on you. But if it's your daily, clean it up and leave it how it is. That way things don't get rushed.
 

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Discussion Starter #5
What's your budget?

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I think the most I want to spend right now is $5000. Down the road I'd be open to some upgrades, but that's the hard upper limit for the initial build. I know this restricts me a lot, but based on my research I am confident I can keep it under budget since I will be doing most of the work myself.

People here don't really talk in crank horsepower numbers. Going turbo you always sort of lose a bit of a reliability aspect. Unless you are really good. I recommend against boosting the stock GE in general. If you are serious just build an engine on the side with GTE/GE non vvti internals, ARP head studs and some fresh seals and you can feel comfortable boosting. It is covered pretty heavily here. I had a lot of fun with 310 whp and I also had a lot of fun on my stock ecu, 10 psi car.(Not saying I recommend that at all, also never dynoed) All depends on you. But if it's your daily, clean it up and leave it how it is. That way things don't get rushed.
I don't expect it to be quite as reliable as the stock engine, but based on my research I don't expect it to suffer much either with a relatively mild build. Does your experience say this isn't the case?

I'd really like to avoid pulling the engine if I can. I've pulled my Corvette's engine I think 3 times, and it's always a painful, stressful process for me (although maybe that's specific to the Corvette - most of the stress is the hours-long process of getting the input shaft lined up and mated with the clutch/pilot bushing).

If the stock internals can comfortably take 300whp, what's the advantage to doing a full build? Like I said, I don't want to cut corners, but I don't want to spend any money I don't have to. I could see the value in the seals, and potentially the pistons since they'll be my limiting factor, but for 300whp I don't see the need to replace crank, rods, and head studs.

This is currently my daily, but I will be waiting to take this project on until I do some engine work on my Corvette and can daily it again.

Edit: I see you answered my first question in my other thread:
My first turbo IS made 310 whp on 5.7 psi of boost. Ended up blowing the ringlands on cylinder 6 though.
How many miles did it have when you turboed it, and how long did it last before the ring lands failed? Did the ring lands take anything else with them when they failed, or did you just need new pistons?
 

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What's your budget?

Sent from my SM-G973U using Tapatalk
I think the most I want to spend right now is $5000. Down the road I'd be open to some upgrades, but that's the hard upper limit for the initial build. I know this restricts me a lot, but based on my research I am confident I can keep it under budget since I will be doing most of the work myself.

People here don't really talk in crank horsepower numbers. Going turbo you always sort of lose a bit of a reliability aspect. Unless you are really good. I recommend against boosting the stock GE in general. If you are serious just build an engine on the side with GTE/GE non vvti internals, ARP head studs and some fresh seals and you can feel comfortable boosting. It is covered pretty heavily here. I had a lot of fun with 310 whp and I also had a lot of fun on my stock ecu, 10 psi car.(Not saying I recommend that at all, also never dynoed) All depends on you. But if it's your daily, clean it up and leave it how it is. That way things don't get rushed.
I don't expect it to be quite as reliable as the stock engine, but based on my research I don't expect it to suffer much either with a relatively mild build. Does your experience say this isn't the case?

I'd really like to avoid pulling the engine if I can. I've pulled my Corvette's engine I think 3 times, and it's always a painful, stressful process for me (although maybe that's specific to the Corvette - most of the stress is the hours-long process of getting the input shaft lined up and mated with the clutch/pilot bushing).

If the stock internals can comfortably take 300whp, what's the advantage to doing a full build? Like I said, I don't want to cut corners, but I don't want to spend any money I don't have to. I could see the value in the seals, and potentially the pistons since they'll be my limiting factor, but for 300whp I don't see the need to replace crank, rods, and head studs.

This is currently my daily, but I will be waiting to take this project on until I do some engine work on my Corvette and can daily it again.

Edit: I see you answered my first question in my other thread:
My first turbo IS made 310 whp on 5.7 psi of boost. Ended up blowing the ringlands on cylinder 6 though.
How many miles did it have when you turboed it, and how long did it last before the ring lands failed? Did the ring lands take anything else with them when they failed, or did you just need new pistons?
Sorry for not cutting out specific parts. But I'm on my phone. I think you are comparing this platform a bit too much to your Corvette. It's different. My first IS was at 140k. Compression was a straight 210 psi. What it came down to was tuning that likely blew the ringlands. They don't take kindly to any kind of abuse. And as much as you say you'll baby it, that's not how you want to treat your turbo IS daily. Shit will happen and any one of those events can be your engines demise. A lot of people bend rods too. Not just ringlands breaking. You want a reliable build for your daily. Unfortunately the stock GE wont give you that. Rebuilding with GTE internals generally isn't considered a full build. I consider it more of preventative maintenance for a turbo. Another thing to consider is the price of engine management. That gets pricey. Just my input. Others may differ. I've never experienced any high power builds. Only fun street cars
 

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For $5k, you could buy a 1JZ, a Link ecu, a fuel pump and some odds and ends to get it all together.

That would provide an easy 300+whp, and you could put aside your stock engine/ecu to reinstall at a later date - if you were so inclined.

Of course, this would be blowing your entire budget on go-fast goodies, leaving nothing in the kitty for all the other crap you'll want/need for your 17 year old car.
 

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Yeah. That's a path I might take too. Even the 2JZGTE automatics are pretty cheap these days. These JDM engines are all pushing 20 years old. I have a feeling the best JDM swaps have already been sold and what's left are the dregs.
 

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My NA-T car that I just sold cost me $4k all in, with $1700 being the cost of the car. No engine management. But it had a freshly rebuilt engine with GTE internals. Was a fun car. sold it to get my wagon. Its possible to get pretty good smiles/dollar, just takes a lot of time to source parts. I think $5k all in for a 1J with standalone is stretching a little bit. A lot of odds and ends add up. Sorry for being a negative Nancy, just how I am. I almost always go terribly over budget lol
 

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I think $5k all in for a 1J with standalone is stretching a little bit. A lot of odds and ends add up. Sorry for being a negative Nancy, just how I am. I almost always go terribly over budget lol
You're probably right. Seems like going rate for a 1J is ~$2k, and the ECU will be close to same. That only leaves about one g note for dealing with all the minutae of getting it all hooked up and tuned. It could easily go over $5k.
 

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I think $5k all in for a 1J with standalone is stretching a little bit.
I'd argue the same is true of a NAT setup though. It's always costs more and takes longer than you expect. That seems to be some universal rule.

The benefit of the 1J/2J is that all the parts are already built for the power you want to put down. Even if you rebuild a GE with GTE parts, it's still not as good as a real GTE.
 

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I'd argue the same is true of a NAT setup though. It's always costs more and takes longer than you expect. That seems to be some universal rule.

The benefit of the 1J/2J is that all the parts are already built for the power you want to put down. Even if you rebuild a GE with GTE parts, it's still not as good as a real GTE.

Oh absolutely, especially for a first timer on this platform you are bound to spend money you don't need to. Or forget certain things, and break others. I always plan to fail just in case. My build that cost me $2300 I didn't waste a dime. But I got some REALLY good deals, and the parts were not exactly top quality. But they worked. The only thing I do not agree with is saying a GE with GTE internals is not as good as a real GTE. That's just incorrect. It's literally the same block, and the head differences are nothing you are going to notice especially at power levels he is looking at. Bottom line is that it'll be able to take the same amount of boost as a GTE. It's also meant to be there, so everything is essentially plug and play. Emissions also won't be an issue. It is easy to go back to stock. It just makes sense for a daily car. To be honest I have never looked into 1J so I can't speak on it. I imagine it is the same deal as a 2JZ-GTE swap. The only real benefit you get is that it looks better.

It's been covered a billion times and the argument can go either way. I am not trying to turn this thread into another NA-T vs Swap thread. But saying it's not as good is just incorrect. #triggered

On another note, start pricing things out on a spreadsheet and be realistic with yourself. If you have any questions let me know. I cannot answer on wiring and stuff. I always used PnP harnesses because I'm scared of wires and prefer a clean job but hate cleaning things up. It's not impossible, everyone nowadays wants to turbo their IS and a lot of people have. If you do your research and make the right choices you'll be able to do it under your budget. Just remember, stock GE block is a ticking time bomb. An imported engine from Japan is a complete mystery and can leak from every seal and have rod knock or it can be perfectly fine. Nothing is cut and dry. Just prepare for it.
 

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The only thing I do not agree with is saying a GE with GTE internals is not as good as a real GTE.
The GTE has both an OEM oil cooler built in and oil squirters to cool the pistons. For driving around and being in boost for 10 seconds, this probably doesn't matter but if you actually push the car say at a track day it will. I agree the block is MOSTLY the same but Toyota spent a bunch of money making a reliable turbo engine. The NAT is missing some of the reliability pieces. Same for the transmission. One was built for boost, one wasn't.
 

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The only thing I do not agree with is saying a GE with GTE internals is not as good as a real GTE. That's just incorrect. It's literally the same block, and the head differences are nothing you are going to notice especially at power levels he is looking at. Bottom line is that it'll be able to take the same amount of boost as a GTE.
+1 :approve:
 

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GE with GTE internals is not as good as a real GTE.
I leave it at this but saying "it's the same" when it's not the same is...odd to me. It might be "good enough" but it's not the same.
 

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The casting is the same. All you need to do is drill out an oil drain for the turbo. Oil squirters aren't necessary and don't have any added benefit. It's the same.
 

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Discussion Starter #17
For $5k, you could buy a 1JZ, a Link ecu, a fuel pump and some odds and ends to get it all together.

That would provide an easy 300+whp, and you could put aside your stock engine/ecu to reinstall at a later date - if you were so inclined.

Of course, this would be blowing your entire budget on go-fast goodies, leaving nothing in the kitty for all the other crap you'll want/need for your 17 year old car.
Yeah. That's a path I might take too. Even the 2JZGTE automatics are pretty cheap these days. These JDM engines are all pushing 20 years old. I have a feeling the best JDM swaps have already been sold and what's left are the dregs.
I'm not going to have the time and energy to do an engine swap. I've done that enough on my Corvette and it sucked every time, even with two of the times being the exact same engine out and in. I'd rather bolt on a turbo kit and make 250 to the wheels than pull the engine and make 350 at the wheels.

I also need the ability to easily return to stock for emissions purposes.

My NA-T car that I just sold cost me $4k all in, with $1700 being the cost of the car. No engine management. But it had a freshly rebuilt engine with GTE internals. Was a fun car. sold it to get my wagon. Its possible to get pretty good smiles/dollar, just takes a lot of time to source parts. I think $5k all in for a 1J with standalone is stretching a little bit. A lot of odds and ends add up. Sorry for being a negative Nancy, just how I am. I almost always go terribly over budget lol
Man, $2300 for all the turbo parts? That's impressive - were any of your parts used, and do you mind sharing yours parts list (or at least the major parts you remember)?

Oh absolutely, especially for a first timer on this platform you are bound to spend money you don't need to. Or forget certain things, and break others. I always plan to fail just in case. My build that cost me $2300 I didn't waste a dime. But I got some REALLY good deals, and the parts were not exactly top quality. But they worked.

...

On another note, start pricing things out on a spreadsheet and be realistic with yourself. If you have any questions let me know. I cannot answer on wiring and stuff. I always used PnP harnesses because I'm scared of wires and prefer a clean job but hate cleaning things up. It's not impossible, everyone nowadays wants to turbo their IS and a lot of people have. If you do your research and make the right choices you'll be able to do it under your budget. Just remember, stock GE block is a ticking time bomb. An imported engine from Japan is a complete mystery and can leak from every seal and have rod knock or it can be perfectly fine. Nothing is cut and dry. Just prepare for it.
I'm an engineer - you better believe I have that spreadsheet going!

Do you really need a harness for a NA-T? The only things I can think of that would need to be wired are an electronic boost controller (if you had one; I'll be running off the wastegate), a wideband, and whatever you do for engine management. I admit, I'm not super familiar with the solutions used on these cars, but the chip emulator I use on my Corvette didn't require any additional wiring.

Are any parts in specific a time bomb, or is it just the engine as a whole?




As I've said, I don't want to spend money I don't have to, but I also don't want to cut corners. Since I'll have another car I can drive, I'm fine with something failing and taking my car out of commission until I can replace it. BUT, I don't want something to fail and take out other components with it. I guess the main deciding factor in which components I replace is: which failure points take other components with them when they go?
 

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Basically the failure points you already listed. Pistons, rods, rings, HG. I'm about to graduate with my BSME in the spring. I can provide a parts list later. That car was on stock ecu. I don't like to get on that argument though because I won't ever win. I'm at work rn. Everything was used. I got a stupid deal on everything. Did all the work myself. My first car cost me 12k all in with a lot of mistakes and wasted money. I was under the impression you were using the wagon as a strict daily. But since you don't mind it being down, you can just yolo it and boost the GE. Most people using pnp harnesses for their standalone and maintain the factory harness. I think the link ECU previously mentioned replaces it but it only works for 5 speed manual cars if I remember correctly.
 

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As far as engine management. Everyone will tell you to go standalone. I agree. But it's expensive
 

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I'm not going to have the time and energy to do an engine swap.... I'd rather bolt on a turbo kit and make 250 to the wheels than pull the engine and make 350 at the wheels.

I also need the ability to easily return to stock for emissions purposes.

Man, $2300 for all the turbo parts? That's impressive - were any of your parts used, and do you mind sharing yours parts list (or at least the major parts you remember)?

I admit, I'm not super familiar with the solutions used on these cars, but the chip emulator I use on my Corvette didn't require any additional wiring.

Are any parts in specific a time bomb, or is it just the engine as a whole?

I don't want to spend money I don't have to, but I also don't want to cut corners... BUT, I don't want something to fail and take out other components with it. I guess the main deciding factor in which components I replace is: which failure points take other components with them when they go?
If you don't have the time/energy to R&R an engine, you don't have the time/energy to "bolt on" a turbo "kit".

A turbo "kit" is not going to be easily returned to stock for emissions purposes.

A complete turbo "kit" is going to cost you more than $2300 unless you buy the lowest quality parts and/or fabricate everything else (and consider your labor @ $0/hour)

The weak link in the GE-VVTi is definitely the rods. If you avoid detonation, the pistons will easily handle (way) more power than the rods. A stock, automatic trans IS300 powertrain will live just fine at 300-350hp if you use the car sensibly and don't rape it. The transmission (whether a W55 manual or the automatic) is not going to last long with 300+hp and very aggressive driving.

A chip emulator or EEPROM is not an option on these cars. You can take your chances running a little boost without doing anything to the engine control system, or you can dig into the electronics. The cheapest (and lousiest) solution is a Greddy eManage, but considering the pricepoint and functionality, you'd be way better off (at least in my opinion) to spend a little more and get a real ecu. For example, the ecuMaster provides lots of excellent functionality for a very fair price (about $1k). However, for another $500-600, you can get an ecu arrangement that is way better yet - which is totally worthwhile in my opinion.

Frankly, IS300s are not like Foxbody mustangs or 3rd/4th gen camaros, or even Corvettes. Parts are more expensive, and the electronics integration is much more difficult to deal with. I would caution you to avoid embarking on a power-adder project if you aren't ready to put a lot of time, energy and money into it. $5k would barely cut it IF you had lots of time/energy. Without lots of time and energy, there is just no way this can become reality for $5k, or anything close to it.

Not trying to be an @$$ about this, just trying to provide the straight dope.

Last... The "balance" of the stock IS300 is really quite excellent. The power, brakes, suspension and dynamics all work nicely as a system. Adding a big handful of power is going to significantly upset that balance and take a lot of the fun factor (and reliability) out of the car - unless all you care about is doughnuts and wheelspin. I have two of these cars - one is all stock with big brakes, the other is a thoroughly modded turbo car. With 100% sincerity, I can tell you the stock one is basically every bit as much fun to drive. I can drive the frickin' wheels off it, and never be going ludicrous speeds. The chassis is supple and compliant while providing decent grip. Again, I can drive it at 7 or 8 "tenths" and never be going crazy fast... Which makes it fun while minimizing the risk of a high speed wreck. Plus, the stock one is OEM reliable - so I can drive the wheels off it with almost no worry of it blowing up or coming apart.

Just some stuff to think about.
 
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