Fiko18

in that case no one will buy it, because for the price difference anyone could just buy an IS-F and you would have a more reliable car and garunteed horsepower and the same look as an is350

pocky

iTrader: (12)

Not every single person can trade in their cars every 2 months cause they want more "power".

You cannot say no one will buy it, people modify a certain car for a reason, for their love of cars, it's a hobby. Sure if you got the money, then trade up all you want over and over again.

Why don't Supra owners trade in for a newer, faster and more reliable car instead of spending so much money in their Supras to get power?

MR_F1

what he said^^^

lobuxracer

iTrader: (2)

Because there aren't any faster cars under $50k, and there are zero options for 1000 reasonably reliable hp unless you want to do something really exotic (like an RB26DETT in a 240SX).

However, if you consider all the costs, it's far cheaper to buy the IS-F and retain warranty, smog compliance, and Lexus reliability. As soon as you put forced induction on your 2GR-FSE, you own any problems that might arise including driveability, fuel sensitivity, and basic reliability of the entire drivetrain.

If your IS is your daily driver - this is a less than stellar decision. If you have other cars you can drive when your force-fed IS is acting up, then it might be just fine. But typically I like to start with the fastest thing I can get, then modify it to be faster. When I raced motorcycles it didn't make sense to buy the underdog in the class because you're always playing catch up.

In my case, I would not trade my IS350 for the IS-F, I trade my remaining tC for the IS-F and keep the 350 for the wife and still keep the Supra.

Fiko18

lobux and pocky, i understand ur point and I agree. I wouldnt turn my car in for an IS-F and i love modding my car because its my passion. All i was saying was that it is alot of money to spend, most of the SC i have seen for other cars are around 5,000, thats why i was shocked at the price. But if it was between these two options

a.) New fully loaded IS350 plus supercharger = about 50 grand
b.) New Base IS-F = about 50 Grand

I would prolly take choice B

jimmyjazz

I'm gonna pick this thread to ask my question about supercharger's or turbocharger's. How can it be done? Our engines already have 11.8:1 compression , jeez even if you have a methanol injection system you'd have to run 104 (unleaded) race gas at like $6 per gallon and you could still only run like 4lbs of boost! You can't put head gasket thick enough or buy like 8:1 or 9:1 compression Head's so you can run 10 or so lbs of boost . If you could you're probably talking at least 2500 bucks IF you could find low comp heads, and bigger (higher flow) , 2 per cylinder, injectors. You can probably get dished pistons but you'd have to totally tear down the engine to put them in. I think with almost 12:1 compression our bolt's and gaskets could be reused but who know it may still have torque to yield bolts and non reuseable metal gaskets. I'm just saying it's gonna take a lot more than the cost of a "kit" to get a daily driver setup that would work and give a good increase in HP and TQ that you could still run on 92octane gas.

lobuxracer

iTrader: (2)

All the bandaids you describe to lower compression would very negatively affect the engine's performance. I would not do them to this engine, it would be an invitation to disaster.

I would start with Gernby's fuel controller. According to the Howard Chu's excellent spreadsheet, just fixing the a/f ratio from stock will net between 20 and 22 hp given all other parameters unchanged. The bad thing is on 91 octane (CA premium), you're already flirting with autoignition from too much static compression. If Howard's numbers are right and 91 octane autoignites at 725F, we're already 6 degrees F too high at stock a/f and almost 10 degrees too high at 13.1 as Gernby shows in this post.

Any boost added will only make life worse for the ECM, assuming conventional engine operation. The big HOWEVER is the way the engine does GDI, and the potential cooling effect the direct injection has compared to port injection. That could be the saving grace of the whole thing.

Some "for instance" is at the OEM 12.3:1 a/f ratio, with only 4 psi boost without any charge cooling, we should see ~354 hp. The problem is, at 4 psi boost without some kind of charge cooler, the intake temperature is 110 degrees F too high. With an 80 percent efficient charge cooler, hp jumps up to 383, and temperature comes within 27F of the target 725F maximum. Water or meth injection could easily overcome that, and might even be able to overcome the 110F, but then you have to recalculate a/f and a bunch of other variables not included in this free spreadsheet.

No matter how you slice it, it's going to be a challenge. The GDI/port injection is going to be the real unknown. How much headroom is there in the fuel delivery system before you go permanently lean? How do you add fuel with GDI when the injectors are unique (they were developed and patented by a Toyota/Denso joint project) and who knows what it will take to properly tune them?

Add to this a proprietary patented piston dome design, and it gets even more challenging.

My bet is you can add some boost - not a lot - and run on 93 pump gas without bandaids, but I wouldn't try it on California 91. If you add meth or water injection, you might get more, but then you're going to find the limits of the fuel delivery system (or severe detonation) first. The one really good thing, because we have throttle by wire, the throttlebody will close the blade if the ECM thinks something really bad is happening to the engine regardless of where your foot is on the pedal.

BTW - all the hp numbers are CRANK, not WHEEL.

jimmyjazz

Some "for instance" is at the OEM 12.3:1 a/f ratio, with only 4 psi boost without any charge cooling, we should see ~354 hp..[/QUOTE]
So for 5000 to 8000 dollars were only getting about 45 bhp. It's hard to modify a badass engine!