Lexus IS Forum banner

1 - 20 of 22 Posts

·
Registered
Joined
·
12 Posts
Discussion Starter #1
If I put a Supra short block on my IS300, how much hp/tq to the wheels could that supra short block hold? Should I just throw some aftermarket pistons and rods in there since I will be having it out anyways? How much hp/ tq can the stock IS300 head take? How much hp/tq to the wheels to break into high 11's
 

·
Registered
Joined
·
6,782 Posts
Oh crap here we go, hope you brought a flame jacket.

B.
 

·
Registered
Joined
·
8,219 Posts
some supra short blocks have been known to hold upwards of 700 to 800 RWHP. There have been some that have hit 900's i believe with a stock TT shortblock.

The IS300 head can "take" all the power you want. If you are asking how well it FLOWS at higher levels of power, thats different. Based on the experiences of many on this site, the stock IS300 head flows 500ish RWHP very well. If you want much more power, lets say 700-800, you should do some headwork for better volumetric efficiency.

Volumetric efficiency= the efficiency of the motor to move air(basic definition). Having a better flowing head will increase your VE. Keep in mind, you will also need a nicely flowing exhaust system. Having a 2.5 inch exhaust with high amounts of power wont do any good. Try 3+ inches. For 650+, try 3.5 inch.
 

·
Registered
Joined
·
12 Posts
Discussion Starter #4
Just new to the site. Trying to get a IS300 and get rid of my 350Z that I have for sale. I am just wanting to know some info before buying. I like the Z, but it costs too much just for a turbo for this car and it can barely handle any power. Plus I need four door car now since married and wife excepting to have kids soon.
 

·
Registered
Joined
·
5,028 Posts
Josh1 said:
Just new to the site. Trying to get a IS300 and get rid of my 350Z that I have for sale. I am just wanting to know some info before buying. I like the Z, but it costs too much just for a turbo for this car and it can barely handle any power. Plus I need four door car now since married and wife excepting to have kids soon.
GL to you on that.
 

·
Registered
Joined
·
1,840 Posts
If you think the Z is pricey to boost, the IS is pretty much up there too. GL on your quest
 

·
Registered
Joined
·
12 Posts
Discussion Starter #7
A basic kit for the 350z runs about $6000-$9000. If you go single turbo it still runs about $5000 for basic kit. The motor can only handle 9psi daily and about 380whp and 390wtq since the internals are fragle. I don't know how much a IS300 can hold, but hopefully its more then the Z.
 

·
Registered
Joined
·
6,782 Posts
^^ Without a TT swap the stock IS internals with head gasket are good for over 400hp, if you get a manual you'll be in a pickle though.

Thought 350Zs make 400+hp with 6.5 psi, and being the high strong well designed NA engines that they are, they have been running into problems with just that amount of boost, hard to believe them running 9psi without lower compression or higher octane.

B.
 

·
Registered
Joined
·
5,941 Posts
Josh1 said:
Just new to the site. Trying to get a IS300 and get rid of my 350Z that I have for sale. I am just wanting to know some info before buying. I like the Z, but it costs too much just for a turbo for this car and it can barely handle any power. Plus I need four door car now since married and wife excepting to have kids soon.
Don't want to be the bringer of bad news but 400 rwhp on an IS will cost you about $10K.
 

·
Registered
Joined
·
6,782 Posts
^^ Yeah forgot to mention like the others, if your complaining about price to boost, then this is one of the last cars to choose from (I'll admit I came into this car not knowing that, and have been bitching and crying since).

But if your really pacient, more and more companys maaay come in on this, and bring a more Honda element to the game, but I being one of the most devote believers in the proficy of lower IS prices= more tuners and cheaper solutions- I have begon to waver on that.

B
 

·
Registered
Joined
·
1,840 Posts
Like i said before IS = $$$ to boost like lambchop stated. basic kit for the IS will run 4500 and that is the cheapest so far.

Secondly i also agree with BlacksportD on his assesment of the 2JZ's strengths and his evaluation of the Z's questionable metalurgy.
 

·
Registered
Joined
·
12 Posts
Discussion Starter #12
A 350Z can handle around 7-9psi on stock internals on the street with really good tuning. They are making 400wheel hp not 400flywheel. That is alot condersing the comp. I know turboeast kits are pretty cheap. How would it cost you $10,000 to get 400whp if a kit that can make that much only cost around $4995. Install on these kits can not be that much since a twin turbo Z kit runs around $2000 installed and has way more things involed in its install then a regular single. Sinlge kits for the Z run cheap for install. Even if you got the stage II for $5995 you still would not be spending $10000 with install and everything unless you bought stuff you really don't need just to be safe. Can the internals hold 400flywheel or 400wheel hp.
 

·
Registered
Joined
·
20,661 Posts
^^ you are leaving out whats NOT included in the turbo kit

Gauges/pod
Boost Controller
GTE engine block + labor to install
transmission upgrades for either auto (valvebody/torque converter) or Manual (clutch+anything else)


then you add up to $10,000 really quickly all said and done..;)
 

·
Registered
Joined
·
1,840 Posts
Like you said if you do get the S2 for roughly $6k just fo rthe kit alone(shooting for 400rwhp), install will be considerably more coz you have to bring down the head, plus tuning will be another pay item not to mention the tranny upgrade necessary to handle this power. Eshift=vb upgrade/ stick= w58 or R154, so hence the $10,000 price tag on it:) . The guys on these boards are very comprehensive when it comes to this, they curtail all the possible costs involved in FI. They make it a point for interested parties to realize the $$$ and effort needed to boost the IS. And this is what separates them from the rest IMO. Happy Moddin
 

·
Registered
Joined
·
5,941 Posts
Josh1 said:
A 350Z can handle around 7-9psi on stock internals on the street with really good tuning. They are making 400wheel hp not 400flywheel. That is alot condersing the comp. I know turboeast kits are pretty cheap. How would it cost you $10,000 to get 400whp if a kit that can make that much only cost around $4995. Install on these kits can not be that much since a twin turbo Z kit runs around $2000 installed and has way more things involed in its install then a regular single. Sinlge kits for the Z run cheap for install. Even if you got the stage II for $5995 you still would not be spending $10000 with install and everything unless you bought stuff you really don't need just to be safe. Can the internals hold 400flywheel or 400wheel hp.
It adds up pretty fast. Lets use the TE stage 3 kit, it's capable of 400 rwhp.

$6K for the kit
$2k for installation (unless you're going to do it yourself)
$500 for electronic boost controller (you can use this for a boost gauge too)
$500 for a decent wideband
$500 for either a valve body upgrade or a better clutch

You're already at $9500. If you're planning to add an oil, fuel pressure, or an EGT gauge you'll be over the $10K mark. If you do the work yourself you'll save a good amount of cash on labor. Another thing, I didn't even factor in the "oh shiet" backup cash if something goes wrong either.
 

·
Registered
Joined
·
654 Posts
Josh1 said:
A 350Z can handle around 7-9psi on stock internals on the street with really good tuning. They are making 400wheel hp not 400flywheel. That is alot condersing the comp. I know turboeast kits are pretty cheap. How would it cost you $10,000 to get 400whp if a kit that can make that much only cost around $4995. Install on these kits can not be that much since a twin turbo Z kit runs around $2000 installed and has way more things involed in its install then a regular single. Sinlge kits for the Z run cheap for install. Even if you got the stage II for $5995 you still would not be spending $10000 with install and everything unless you bought stuff you really don't need just to be safe. Can the internals hold 400flywheel or 400wheel hp.


The word "cheep" should never be in the same sentence with boosting an IS300. It is going to cost money plain and simple. Even after you boost it. They weren't made to have that much power. So after you have your boosted IS save because shit brakes. Its an expensive hobby. Don't think you are done after your car is built. It has just begun.


Paul
 

·
Registered
Joined
·
6,782 Posts
^^^ Actually I agree with everything but the brakes part. There are a lot of Gurus here that will say that our brakes are pretty up there short of some cheap upgrades. The expensive part is the stupid EMS situation and the high price for fabricated parts (manifold, intercooler piping) plus the fact that is that if you have a manual, you'll most likely have to upgrade the whole transmission. Actually I should say with most cars you have to upgrade the tranny, but with Hondas its cheap to do so, as oposed to our situation, but thats kinda changing lately.

B.
 

·
Registered
Joined
·
12 Posts
Discussion Starter #19
I just think it is alot cheaper to build a IS300 then a 350Z. Someone of the Z forum has put in around $16,000 and just now hit 500whp mark. If I only spent $10,000 on a IS300 and did everything at once with a Supra shortblock, there would probably be no reason that I should not hit at least 500whp.
 
1 - 20 of 22 Posts
Top