Lexus IS Forum banner

1 - 20 of 782 Posts

V8 Sportcross
603 Posts
Discussion Starter #1 (Edited)
Since the noise to information level in the other thread is a bit overwhelming, I figured I'd start over. The original thread is here:

*edit* Old Faq for this swap can be found here:
v8 IS300 swap FAQ

To summarize, I have a Yellow 2002 Sportcross. I'm repainting the car to a better color of yellow.

I started disassembling the car for paint and the engine swap earlier today. I only had a few hours, so I had to stop before I got too far into it.

I'll have a photo diary and some basic commentary here later this evening:

Until then, here are some photos:

Left rear, mostly disassembled and ready to start paint prep. (I still need to remove some trim, door handles and glass)

The photo numbers go up sequentially if anyone is feeling nosy :)


Adding a FAQ:

Lexus V8 swap FAQ:

Photograph journal of this swap can be found here:

My parts list:
2002 US market IS300 Sportcross
99 GS400 engine with VVT-I
99 GS400 ECU & Wiring harness
00 GS400 Transmission + stock IS300 transmission
01 Tundra Power Steering Pump & Reservoir
00 GS400 AC compressor, alternator
Aftermarket Aluminum Radiator
Aftermarket Transmission cooler
GS400 Throttle cable, lightly modified.

The 99/00 GS400 harness will damn near plug in the 01 chassis. The 02 IS300 chassis uses different ECU connectors.
You'll just have to repin the junction connectors on the body or the Engine harness. I build an adapter harness to adapt the two different generations of wiring harnesses.
Had I used a GS430 ECU and Harness in my 02 IS300, this would have been better.

For the most part, the GS,LS and SC 400 parts interchange. You'll want a GS wiring harness or maybe an SC wiring harness to fit the chassis best. LS wiring puts the
ECU in the wrong place.

Physical fitment:
GS/Sc motor mounts bolt in. There is a bit of an angle to the crossmember, but being rubber they flex enough to not be an issue. If you're really anal,
you can build custom brackets or modify the crossmember/subframe.
Light dimple in the firewall on the passenger side if I recall correctly. I think there was a minor interference with the head or a bolt.


Take the GS bell housing and input shaft and put it in the IS trans
Take the Output shaft and tail housing out of the IS300 Transmission and put it in the GS transmission. This way you get the V8 clutches and stronger parts.
This way, your driveshaft, shift linkage and transmission mount bolts up.
Photos of this swap here:

Another option that I did not explore is putting the IS300 Torque converter & front pump on the V8 transmission for a higher stall.

Notes: You can also use the IS300 transmission with the V8 bell housing and slot your flywheel a bit or swap front pumps so that the v8 torque converter works. It will eventually fail due to the torque, but this can be a 2 step process.

It's a stand alone unit. Just needs signals from the ECU that the car is running and driving. 99 GS400 and 02 IS300 communicate with each other fine.
You will have to relocate the unit. I straightened out the brake lines and moved the unit up and to the right. When I get around to it, I'll be moving the ABS
module up next to the master cylinder. I didn't want to do this initially as I had planned on going to a Manual gearbox.

Power Steering:
Build a custom reservoir bracket and use the Tundra reservoir hose. I built custom pressure hoses out of my old IS300 hoses.
A trip to the local hydraulic shop will do the trick. You lose the variable power steering with this setup, but I don't miss it and it fits the chassis better.


Build custom hoses.
The 99 and GS Multiplex signals communicate fine and allow the climate control to work well.

I went to the local parts store and found an upper hose that worked. The GS lower hose fit right in with the IS300 radiator. I did not keep the part number.

Fuel line:
I took the stock IS300 line to a local hydraulic shop and had them put quick connection connectors on both ends to fit the engine to the body.

Heater hoses:
Due to interference with the head, the lower heater core pipe needed to be bent up about 45 degrees. Be careful here, you could break the heater core.
Otherwise, I used GS400 or IS300 heater hoses. I forget which, but it wasn't difficult.


I had to build a custom set of headers, I didn't try the factory manifolds. They would probably work with some minor reworking. However, they are pretty poor in
design and I wanted to avoid them. Even my ugly thrown together header/exhaust works better.

immobilizer security:
There are several places on the web that can clear out the ECU. I had a local parts shop do it for me. They charge 400 for ones they can flash.
If they can't flash them, the later model ECUs can be re-seeded with a new key info. This requires a toyota scan tool and contact with Toyota USA. A local dealer can do
this for you. Cost is usually 1-2 hours of labor and having the car present.

Supercharger/Forced induction:
I picked up a TRD Tundra 2uzfe supercharger last week. I know it physically bolts on, but have not run through the full installation issues.

Supercharger is 3.25" taller than the stock intake. If I remove the hood structure braces and insulation, I gain 1" and still have roughly 1" of clearance between the engine & hood. So that's 2" found, I'm still about 1.25" too tall with the SC.

hood modification will be necessary for this SC.

What doesn't work with my current swap:

I've been driving this car for four years as of 6/2010.
The car is 100% OBD II complaint. No check codes, no funny business.
Coolant gauge doesn't work. Using the OBDII scan tool, I know the engine knows the temp, but seems the BEAN code changed just enough so that the gauge cluster doesn't know
what the coolant signal looks like. I still don't have a work around for it.
Traction Control, another part of the MPX not working. I didn't use it anyhow, so not a big loss.

Speed sensor reading in the ECU isn't quite happy. cruising at 100mph, the ECU thinks the car is going around 125mph. At slow speed, this causes the transmission shifts to be a about 5-10mph earlier than
they should be. At low speed, ~35mph, it'll be in 5th gear and lugging a bit.
I believe this is caused by the V8 thinking the rear end gear is ~3.23:1 vs the 3:73 I have in the car. I seem to recall using the V8 speed sensor on the tail of the transmission as opposed to the I6 speed sensor.
I'll track this problem down later this year and publish the answer.
**Note this shifting is fixed. Solution: Make sure ALL shift indicator wires are hooked up to the transmission shift module***

*IF* I were to do it again:
I'd do a GS or SC 430 ECU and harness with either a 1uz or 3uz engine, depends on what was cheaper.
GS or SC430 throttle pedal for inside the car to remove the throttle cable from the engine bay and go fully Drive by wire.
Spend more time on the headers, mostly to make them more pretty.
Move the ABS unit and use a factory air box to silence down the growl from the engine when on throttle.

****I did it again****

Oil pump failed on the GS400 engine. I built a 5.2 stroker and started with an iron block Tundra VVT-I block.
Mild port work, combustion chamber work for the larger bore.
GS430 computer (2002) did not work, couldn't get the dash to work, so I quit and went back to the GS400 ECU.

Why I did it:
I'm a big fan of well engineered improvements. Simply bolting a turbo to the 2jz would have one the trick for me, but that really doesn't say much for my talents. With as well engineered as kits are today, making a 2jz fast is, quite frankly as easy as whipping out a credit card. That's just not me. I get 25mpg on the highway while cruising at 90mph and 19-21 around town with reasonably aggressive driving habits. The torque curve is borderline flat and very controllable. While power isn't overly impressive, it still is 270 hp at the wheels and enough to run 100mph traps at the local drag strip.

With the 5.2 and blower with transmisison mods, this car is super fast. It's at least 2 seconds than my 996 turbo from 0-120. I'm expecting high one-teens to low 1 twenties for 1/4 mile pass being seriously traction limited.

Feel free to use and distribute this information to everyone who might need or want it. I only ask that credit is given where credit is due.
While I believe it is reliable, I cannot guarantee any of it. Please link credits to

799 Posts
Very nice!! Keep us updated. :)

V8 Sportcross
603 Posts
Discussion Starter #6
dasgalloway said:
Haha this guy is putting a V8 into a SportX? :lol:

Awesome! Good luck.

Ya, and you'll be lucky if I don't decide to just widen the stock wheels to 9" and keep all the rubber tucked under the fenders for that 'stock' look. :cool:

I've done the swap 4 times on paper. I've sorted through every possible issue. At this point, it's all a matter of man hours.

I expect paint work to be done by next weekend. After that, the engine will be put in and I'll start the process of hooking it all up.

I honeslty think the equal length long tube headers will take longer to build than the wiring.


V8 Sportcross
603 Posts
Discussion Starter #8
LPO867 said:
hows it turning out?

It's making over 1,000hp in my head. :)

Seriously, though I'm only 3 hours into it currently. I expect to have the 2jz out of the car tomorrow, as well as all the trim removed from the car. If I have time, I'll toss the v8 in to check and make sure I don't need to clearance anything with a BFH before I blow paint in the engine bay.

I'm a bit concerned about the electronics. However my backup plan is to piggy-back the IS300 ECU until I can develop a converter box that reads the necessary sensors and broadcasts the correct signal on the BEAN network.


1,503 Posts
wow this sounds awesome! can't wait till its all done :)
are you planning on doing everything by yourself? by that i mean, paint & engine, etc?
good luck.

V8 Sportcross
603 Posts
Discussion Starter #10 (Edited)
Yes, I've been known to be pretty handy with a paint gun, here are examples of my work. My last car scored 2nd place in show at the USCC competition. Second only to the high dollar Sparco Evo:

My last car I built for myself:

The car I built for my wife.
Beth's car

I do have someone hired to come help out with the labor. But honestly, he'll mostly be sanding and cleaning and learning the entire time. I expect in the next two weeks, the two of us will log a minimum of man hours into this car. (150 hours each)

Since the current paint job is borderline perfect, prep work will go very quickly. The time should be enough to get it running and have a short 'todo' list of any bugs that remain.


V8 Sportcross
603 Posts
Discussion Starter #14
FSUnoles said:
is that the same engine used in the sc400 series?
For the 98-02 cars, yes. This is the higher output VVT-I engine. ~310hp

I've considered opening up a shop, but honestly I keep plenty busy here at my house. I have about 1,000sq ft and more tools than most performance shops own. Not to mention, I keep it pretty effecient. (except when I'm working on my own stuff).

V8 Sportcross
603 Posts
Discussion Starter #15 (Edited)

More photos are here:

So far, no surprises. I'm using the 2jz motor mounts, but I don't like how they fit. I'm going to go pick up some 1uz mounts tomorrow and slot the lower crossmember about 1/4" so that the mounts are not in a bind when at rest.


4,254 Posts
AWESOME! There are two yellow sportcrosses in my area here. I just recently spotted them and before that I had NO idea they existed in yellow. Glad someone on here has one!!!!!!!

Cant wait for the end result. +rep for you for having the only SY SportX on here that I know of

2,291 Posts
baddest sportcross in US? Maybe!
1 - 20 of 782 Posts