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i can get some cams cut for around 2k. there's already a company making that much power on the 250 with a supercharger. i realize that there's been people in and out of your lives filling your heads with empty promises. i have the knowledge to make your dreams come true. as far as the pistons go there 10.5:1. not too much lower but the stock block is only good for about 14psi anyways.

YouTube - RGMotorsport's Supercharged Lexus IS250

280kw = 375.5hp

375.5hp vs 306hp
Yes, but nobody believes them.

There's been a couple threads on that company here and on CL, and several folks have pointed out the math on their website doesn't make any sense.

(their "after" 1/4 mile times are similar to a stock IS250 for example... and while they're running at altitude it shouldn't make near as much a difference for that much boosted power as their track #s show)

Further, they claim to make that with some sorta engine management they haven't really explained and nobody else has ever duplicated.

Oddly their website seems to have removed the 1/4 mile times they used to have posted.

But their numbers are still off.

For one, they're claiming 240 AT THE ENGINE, not the wheels.

But they still post only 163 kw at the wheels... yet somehow 240kw at the engine.

Which is a massively larger drivetrain loss than the 250 actually has. That's like nearly 3 times the actual drivetrain loss.

163kw is 220 hp BTW, a lot less than a 350 makes.

And they claim they only made 140 at the wheels stock, which is ALSO much lower than anyone else on earth.

In other words- they're lying about the stock HP their car made, and about the "engine" hp their kit makes.

220 at the wheels, which is what their dyno shows with their kit, is only about a 40-50 hp gain from a "real" stock 250. Which is in line with what other kits have produced. THAT I can believe.

But it makes your goal of 375 hp at the wheels pretty clearly unrealistic.

Oh, and they only manage the 220 at the wheels with a liquid intercooler and their claimed piggyback ECU too.


The fact you didn't notice the problems with their numbers leaves me a bit concerned about how much research you've done on this though.


as far as the pistons go I'm not sure if I'm ready to release that info at this time but ill give you a hint for shits n giggles... 2010 fj cruiser has the same bore as the is350 and is a 1gr-fSe

so you should be able to use the rotating assembly in the 1gr-fse to yield a 4.0 is400 ill be offering a kit for this as well.
There again- what's going to run the motor? The Lexus ECU can't be reprogramed, and you can't use the ECU from a different car and get the rest of the OEM systems to work.


Do you have a good source showing an fSe motor in there though?

Wiki is showing it uses a 1GR-FE, but with VVti added for 2010.

Toyota announces pricing for 2010 models, upgraded engine for FJ Cruiser — Autoblog

Also mentions dual vvti and upgraded rocker arms but no D4S system addition.

Good catch if that's the case though (and you have a solution for fuel/engine management)
 

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yup. do 10.4:1 keeping the spark the same and adjusting the fuel will take care of your knocking issues. leaving the limitations to the oem fuel system and the block as long as meth injection is used. im working on engine management now. hopefully ill know something this week. once timing is figured out ill have the 2.5 close to the 375 range. i am working with alot of limiting factors, but i have some big names to back me up so im not worried about failing. even if i have to stroke it to a 3.1

i will get a set of these 9:1 pistons and show you that this is all possible.
modding these cars will be alot easier then you think.
 

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yup. do 10.4:1 keeping the spark the same and adjusting the fuel will take care of your knocking issues. leaving the limitations to the oem fuel system and the block as long as meth injection is used. im working on engine management now. hopefully ill know something this week. once timing is figured out ill have the 2.5 close to the 375 range. i am working with alot of limiting factors, but i have some big names to back me up so im not worried about failing. even if i have to stroke it to a 3.1

i will get a set of these 9:1 pistons and show you that this is all possible.
modding these cars will be alot easier then you think.
I'm still not following how you're getting 375 out of the 2.5L on 7 psi.

As I just pointed out to you the SA guys only got 220 whp with 7 psi.

Where's your extra 150 hp coming from at the same boost?

If you mean you now have changed your plans to get 375 out of a build stroker motor with forged internals and engine management I'd say sure, maybe. (though honestly if you only get 50-60 more hp out of 7 psi, as all the evidence suggests, I'm not convinced you're gonna get +200 hp out of the 14 psi the block will hold with a low enough CR).


But you'll now be looking at a lot more than 8k for that.
 

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your right. theres no way to make any kind of real power from it. when im able to get the spark taken care of then i can take all the timing out and add meth to the kit and hopefully get 10 lbs out of it, thats the only way the motor will make the power that the is350 comes with from the factory. im still making the kit for the countries that dont offer the 350. but other then that ill be offering motor swaps and a turbo kit for the is350. i can make 425 whp with it from the same setup. the is 250 has no market unless people want it made.
 

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Please re-consider this project, it is not worth the time and money. Not to mention the transmission nor motor can handle large amounts of power, the IS250 was designed as an economical daily driver. If you want boost I'd recommend starting off with an ideal platform like the IS300. The IS250 will only hold you back and empty your wallet.

But if you do get this done I will give you all the respect in the world, good luck!
 

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IS300 will empty your wallet also but its oh so much fun......
 

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Much respect to Lance for doing the 2JZ-GTE VVTi swap. Seems to be the only viable way to get around it... and not cheap.
 

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Please re-consider this project, it is not worth the time and money. Not to mention the transmission nor motor can handle large amounts of power, the IS250 was designed as an economical daily driver. If you want boost I'd recommend starting off with an ideal platform like the IS300. The IS250 will only hold you back and empty your wallet.

But if you do get this done I will give you all the respect in the world, good luck!
Why do you say with such confidence that the motor can't handle the boosted platform? Do you know how these internal cast iron pistons are manufactured and why they're much higher grade then a regular cast iron piston?

You don't need forged pistons to run 7 to 8 psi on the stock IS250 motor. The connecting rods are already forged and would probably be the first components to blow if the car is overboosted..

People are not building 500HP race cars, you can easily squeeze 80 to 100HP if you set this up properly, and you will still maintain a reliable, luxurious and fun DD...
 

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First of all you guys do realize this thread was started in 2006 and the last post was in 2011 right?

Second of all if you REALLY want to boost your is250 I would look up Adam's is250 on clublexus. His username is heyarms and he has a supercharged is250. I don't know much about it since I haven't followed his build lately but I met him in person before and he got it to the point where he could daily it if he wanted to. He actually used it as a DD before he got another DD and went all out on the is250.

Personally I say its not worth boosting a is250 because in the end you'll spend about 8-12k to do it right and at that point I would just sell the is250 and use the extra money to buy a is350 or is-f. However if you wanna do something different be my guest, and props to you.
 

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I say keep the IS250 stock until they release the newer generation with the turbo 4-cyl. Get one of those and replace the pistons/rods and pioneer the next gen movement!

Goodness just think of all the rep! You will be a literal god among men lol
 
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