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I'm going to supercharge my IS250. I have installed Invidia midpipe and catback. Guys from Armaspeed are ready to ship stage 2 kit which includes: Supercharger, fitting stand (a set of idle gear and a set of air filter), air intake, oil supply computer system, injection nozzle, breed valve and inter cooling. ARMASPEED

Question: Does anybody have ARMA kit installed? What disadvantages does supercharger kit have? Thanks for your comments!
 

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Yeah, it cost twice as much as just buying an IS350 rather than a 250.... and likely adds considerably less power than said upgrade will.

At 12:1 compression and the stock ECU/fuel you're not going to safely run more than 5-6 psi.
 

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Also maintanace of the kit and/or replacement parts could be a hassle.

I was in communcations with Arma about the fitment for AWD. But havn't heard anything back in a while. They were looking to get support from a local shop to have the install done. I was more interested in a DIY kit at a discount so that they could perhaps gain some exposure.
 

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If you got a 0.050" bigger head gasket then you're compression ratio would only be about 10.0 I think... The N54 BMW engine uses 10.2:1 and its boosting over 500rwhp on stock internals.
 

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If you got a 0.050" bigger head gasket then you're compression ratio would only be about 10.0 I think... The N54 BMW engine uses 10.2:1 and its boosting over 500rwhp on stock internals.
There's a reason that "slap on a thicker head gasket" is a poor solution for this motor that has been discussed in some detail elsewhere.


Edit- Found it-
http://www.clublexus.com/forums/4267714-post33.html


Yes it will lower the compression ratio, but it will also ruin the squish height and in all likelihood create more opportunity for detonation. All the late model Toyota engines use an angled squish area to force the a/f mixture toward the plug in the combustion chamber. If the gap between the piston and the head is too great, this effect won't work and will promote detonation. So, a thicker head gasket is a really poor band aid.
There's a diagram of it in the link as well


Lower compression pistons are the other thing most often mentioned- but there's a technical challenge there too, the crown has a very specific shape to make the stratified lean intake charge work properly without detonation.... so any pistons that change the shape would have to be engineered to manage the same trick, which AFAIK nobody has successfully done.

There's one fellow on CL that sent a stock piston to a company to have them custom design some low CR ones with this in mind, but AFAIK he has not received anything back yet, let alone actually tried this in real life.

(and obviously a set of custom pistons, and swapping them, is not inexpensive)
 

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Not too small for a s/c. But above recommendations i would also do, 1st gen boost, or 350. Depending on your mileage already, maybe even save up for enough to compensate for an F and be on your jolly way.
 

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water injection would go along way on super/turbocharging a 250/350 engine it effectively raises the octane on the fuel are using, keeps carbon down and lowers egt's
 

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Yeah, it cost twice as much as just buying an IS350 rather than a 250.... and likely adds considerably less power than said upgrade will.

At 12:1 compression and the stock ECU/fuel you're not going to safely run more than 5-6 psi.
what if he wants a manual? cant get that in a 350 so it might be worth it to him so he can keep 3 pedals. pls dont start some dumb argument with me about this either, some people might see it worth if they are like me and only wanna drive a stick
 

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what if he wants a manual? cant get that in a 350 so it might be worth it to him so he can keep 3 pedals. pls dont start some dumb argument with me about this either, some people might see it worth if they are like me and only wanna drive a stick
So then he'll have a rigged-up engine with a crappy manual.


Wouldn't it make a lot more sense to convert a 350 to manual?

You'd have more power, in a factory-reliable engine, and a significantly better manual transmission as well.

It'll probably still cost a fairly dumb amount of money (I think the 6-speed manual kit from Japan is like 6-8k) but you won't supercharge a 250 for less than that anyway and the 250 route would get you inferior results in every sense.

Only issue might be any fittment problems adapting for LHD.
 

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yeah i really know nothing about the new IS's, besides what i've read on here about how hard they are to do anything, so i was just saying that might be a reason. i love the look of the new IS but if i had the money i dont think i'd get one just bc of the lack of a manual for the 350, tho i had no idea they had a manual conversion for the 350 in japan, kinda cool imo.
 
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