ChaseTran

As the title suggests, I'm looking for some spare info on building my 04 GS300. As is, the only upgrades the car has is a K&N Air filter, an aftermarket harmonic balancer (bc mine broke and blew my engine, making me pay to rebuild it), aftermarket radiator. While I have done some pretty extensive research through the forums aswell as the is forums, I still have yet to find a comprehensive guide for the 300-400 range. Almost always, I run across people saying "just by the gs400," "give up you'll never get it there," or "just turbo it." These responses are decently true, but they are insanely uninformative of the actual question at hand. Unfortunately, I don't currently have the funds to do a full turbo build (however I am hoping to in the future). At the end of the day, my GS is my daily driver. I unfortunately cannot risk unreliability, so please do let me know anything about this.

With all of this info out the way, time to get to the question at hand. My current view for the cheapest way to get to 300-400 hp while staying NA is as follows:
- bigger injectors
- transmission upgrades such as cooler (if at 350 or higher)
- upgraded internals (although if I am correct, this won't do anything w/o a tune and/or other mods (and neither will the injectors))
- weight reduction (which I have done to the biggest extent possible without stripping the panels, carpet, seats, etc.)
- gearing changes
- upgraded cams

I know that exhaust and intake are the first recommended upgrades. However, I have heard extremely mixed answers on the ones to use, with some saying the SRT is a scam, some saying any change at all is useless, etc. At the current standing, I may get a custom exhaust, and only swap the intake piping, but I am by no means certain on these choices. If anyone can give me a comprehensive answer for these, it would be much obliged.

If I have missed anything at all, please do let me know. Another question is, of the things listed, what would get me the most HP for the cheapest (WHILE STAYING NA)? Please do not just reply saying things such as "not possible," "give up and buy a different car," or "not possible for cheap." Yes, I know it won't be cheap and am very aware of the approximate cost. However, that doesn't mean I'm not going to try to get the best deals and take the cheapest route...

Any and all help, suggestions, or even extra info that may assist me in creating a build is appreciated. Thanks.

eicca

The reason you haven't found answers is because of basic physics. Basic physics states that the gains you're looking for will not happen without increasing displacement to pull in more air or adding turbos to push in more air.

You could swap intake and headers, mill the heads to increase compression, swap cams, port and polish the intake, but by the time you got all of that done you'd gain MAYBE 40hp, have spent far more money than just buying a GS400, and still get destroyed by a GS400 if you tried to race. Not to mention the reliability of your engine WILL be put in question with that kind of invasive surgery.

-You could install bigger injectors but the computer will throttle them back to maintain the air/fuel ratio so they'd be pointless.
-Transmission upgrades would help make what power you have get to the wheels better, and yes, that would yield tangible results. You could shim the accumulators and install a high-stall torque converter. This is the only thing I can say would actually offer improvements.
-Gears are already as low as they can easily go for your car. There aren't any lower-geared diffs that will swap in without tons of work.

Just get a GS400. There is no such thing as cheap power. That's why I got a GS400, because it IS the cheapest power.

(ISF owners get lucky and can unlock as much as 80hp with intake and headers but that's a very rare case)

Best of luck.

ChaseTran

New question, then. Ignoring hp gains specifically, how could I go about improving acceleration in terms of 0-60 and quarter mile w/o forced? As I said earlier, I do eventually plan to turbo, but it just won't happen for another half year or so when I can really find the time and cash to get it done. Thanks for the brief write-ups. I do understand that a GS400 will be cheaper, but that just isn't the route I want to go. In the end, I do mainly street race, so 0-60 times for digs and quarter mile for 40 mph rolls are what I'm most interested in of all.

eicca

ChaseTran

I appreciate this info. I just have one final question: With the tranny upgrades, intercooler, ecu piggyback, and bigger injectors, what would be the min. turbo size to run ~400whp at around 8psi? Aside from that, I'm not too knowledgeable about the different turbos available, so suggestions for a couple turbos w/ info on them would be appreciated. I'm also about to weld my diff come next week bc the open diff almost threw me into a curb, so that's happening, too... Lol

eicca

I have no knowledge about turbos so hopefully somebody else can chime in.

ChaseTran

All good, thanks for your responses though man. Never thought ab the pressure dial or shimming the accumulators. Will definitely be doing some more research on that over the next couple months in preparation for the next phase of my car.

https://gyazo.com/de0f9dc0088e70e63337c90be9397b2a

firelizard

iTrader: (1)

NA-T (2JZ-GE + aftermarket turbo) has been done a million times. Everything under the sun has already been done. Full NA build has been done in Supras and the results are barely more power than a stock V8, for an absurd amount of money and worse driveability. But it sounds really cool. The info you need is already here if you use the search function.

ChaseTran

I've been searching these forums for months. Every post I find is always filled with nothing but people who say to search for it... There may be posts somewhere, but they are more than likely insanely old, unfindable, and all reference websites or parts that can no longer be found without shear luck on craigslist. I have found numerous forums that give me pretty great information, but none of them ever say parts they actually use (just general names) and they never give much detail as to why they chose their options. Ontop of these, aftermarket parts aren't really made for the GS. There are a lot of people who say some IS300 parts can work, but it would be a losing battle for me to aimlessly buy IS parts just to find they are incompatible. Thank you for the reply, but please do try to add substance. Even just informing me of different parts, techniques, or aids can help greatly.

firelizard

iTrader: (1)

That's absolute baloney. I searched just now, on this site, and found multiple parts lists, pictures, and DIY information. It took about 30 seconds.

But I'll still give you this tip: buy this book