dejacky

iTrader: (2)

Car = Lexus SC300 5 speed
Goal = 400rwhp max with widest powerband & soonest power delivery in rpm range

1) I want to sacrifice as LITTLE low end power as possible, so I don't want a headgasket that is too thick. Will the Stock tt (2JZ-GTE) head gasket be ideal for me, or is there a specific head gasket thickness & brand that will better help me achieve this goal?

2) While I'm replacing the head gasket are there any other gaskets/seals/etc it might be adviseable to change on a 130-150k mileage engine?

PARTS:
MAP-ECU (MAF removed)
DaveH manifold + DaveH midpipe + shorty DP
Tial 40mm wastegate (recirculated back into exhaust)
ARP Head Studs
HKS SSQV BOV
TE-44 turbo
RX7 550cc injectors flow tested to safely flow 605cc
Supra tt fuel pump
Supra stock tt sidemount intercooler
Generic manual boost controller
EGR Block Off Plates
ABS Heat Shield
Turbo Blanket


Thanks in advance for answering my questions !

reamemiya

iTrader: (1)

tt head gasket will do it for 400hp. everything looks good to me.

dejacky

iTrader: (2)

is it a bad idea to a use a used tt headgasket instead of a new one? If it is, does anyone the cheapest price I can find for a new unused supra tt headgasket?

ki_soarer

if you are willing to spend the cash on a decent turbo set up, why skimp out oh the headgasket? most aftermarket ones go for about $200-$250, new ones are about $100 from the dealer if im not mistaken. dont use a used headgasket. just do it right once, and then you wont have to worry about it. just my $0.02

dejacky

iTrader: (2)

Okay,
I'll use a new head gasket. Someone mentioned that the NA sc300 compression in the motors is higher than the NA supra motors? is this true? I've heard of people boosting fine on 1 bar with stock tt headgasket (1.2mm) on a 2JZ-GE motor, but now a few people on the forums are telling me the 1.6mm apexi or hks headgasket is better for my goals?

Todd_A

From what research I've done, it looks like we are at 10:1 compression. I Was told that a 3mm gasket would take us to about 8.7:1. For what you are talking about (not wanting to loose much low end before boost) I'd suggest looking for about a 9.0-9.2:1 with limited boost levels. I wouldn't feel too safe around 1 bar or higher with that compression. Timing will play a major role in your setup.

good luck man!

aliga

iTrader: (147)

2mm brings you to 8.5:1, 3mm brings you lower.

dejacky

iTrader: (2)

I've been reading about this device: MSD 6BTM that enables users to retard engine timing 1-3 degrees per pound of boost. How much max RELIABLE boost could I run with NA stock headgasket and this MSD B6TM? It seems like it would help me raise rwhp reliably on stock motor without doing a headgasket upgrade.

2jznat

10 psi on race gas no higher

dejacky

iTrader: (2)

forgot to mention i'll only be using 92 octane pump gas max...but from your statement, the 6btm won't really help me add much boost so stock tt headgasket seems like the way to go for 400rwhp on 92 octane pump gas safely?

2jznat

i'll have to agree with that completely

dejacky

iTrader: (2)

thanks everyone that helped. It's great to get positive and helpful feedback on these forums. Expect pics IF and WHEN this project is done

dejacky

iTrader: (2)

Also,
I'm just curious what would be required to build a 10:1 compression 2JZ-GE NA-T with this turbo and 400rwhp goal? Would I need stronger rods and pistons only? ...couldn't find any info when I searched

Dx3

iTrader: (13)

Hey man,

Was replying to your IM when u signed off. I would PM Bean and ask him - that cat knows his stuff

Jonny

Bean

iTrader: (1)

I completely disagree with that...

try 16-18psi with race gas

I ran 10psi all day long on 93 octane and 12-13psi on 93 octane + toluene

Stock TT headgasket will get you ~8.75:1 compression or so... thats PLENTY for making 400whp... hell even 500 or 600whp

if you are running 92 octane and dont plan on making more than 400whp, i'd just suggest using the stocker.... (gasket i mean)
now if you've psyched yourself up for it, you might as well go ahead and do it... because you can also clean up all your other parts and ensure a perfect install with regards to the injectors, FPR, etc...

stock TT headgasket would suffice perfectly fine for what you want to do... but a 2mm Greddy would ensure that you have a 8.5:1 (not THAT much difference honestly)

a MSD BTM works great if you're going to run higher boost on stock compression (like 15-17psi on race gas)... but if you're upgrading the headgasket, there's no point honestly... just get the tune right (with whatever fuel controller) and you'll be fine

and last but not least: do not use a USED headgasket... just fork out the extra cash for a NEW one... TRUST me.... new parts are always better than used parts (unless by the term used, you mean taken out of the box )... you've really got to judge for yourself if its worth it... a gasket is NOT something you're supposed to use again tho