15psi on a stock fuel system is the gereral rule..YOu might be able to up it a little bit, but you gotts make sure you dont upp it too far and run itno fuel cut.It feels like hitting a brick wall head on while driving..So be careful..But if you stick with the 15psi rule of thumb, you will do just fine..

Also your mod list should be added to your profile for future reference on tech questions..

A fuel pressure gauge would only show that the fuel pump is still providing enough fuel. It won't show that the injectors are maxed out or that you're running lean.

What you need to get before you can really start to push your setup:
-Wideband o2 setup
-Logging software that will show knock

Any idea on what logging software I should buy ? Im not looking for beast stuff as I wrote earlier, I just want something reliable. 15 PSI is more than enough for me, for now And for the wideband 02 sensor setup, I'm pretty lost in this, any links where you get to see what you need for it, how it works, and how to install it?

I already read a lot, but there is still some stuff I can't find info on... I do use the search button but I can't find everything even If I want to

Ecm link is a good one to use

Yeah but to use this one I think you need to have an EEPROM ECU, which was found in 1995 dsms mostly. I got a 1999 one. Am I right?

You can get your non eprom converted to eprom..But if you really want to start pushing you car..a wideband 02, dsmlink, larger injectors, fuel pump, and aftermarket fuel pressure regulator would be wise purchases..

Look into ceddy mods if you have a 99 ecu.

+1 on the ceddy mod..

I think that was a waste of time to swap out a gs to the 4g63. Dont get me wrong your friend had some talent but the fact that you only named a few mods. My advice is dont just take a guess and say stuff is stock unless your friend said it is all stock. Stock injectors are 450cc injectors I would check to see if there is bigger injectors and an upgraded ignition system but as boost goes it depends on the turbo. It depends on the injectors and ignition and most importantly the internals but with the 4g63 compared to my 420a you dont have to do a lot of engine rebuilding to boost the hell out of the car. I would stick with 15 psi with a T28 but just remember the bigger the Turbo the more boost you can run and the more power you will get per psi. the smaller the turbo the faster spool up you will get. Lets just say you want to be fast but still have your car a daily driver you would run 7-10 psi but if you chose a smaller turbo you wil be faster on that turbo at low psi than you would with a big turbo.

He has a spyder listed in his profile so he would of had a 4g64 not 420a, making the swap not very difficult at all.

OP I suggest ceddymods as I have personal experience with it, and a cheap ebay vag cable with evoscan to datalog with.

I would not doubt if there was more aftermarket parts in that car I would check around. but good luck anyways and diffenitely decide whether you want to make this a daily driver 14s and up, a summertime sports car(low thirteens to high 11s) or a track wielding beast (high tens to low 11s.) its all about the money, obsession and if its something you want to do. I chose the summertime beast myself and I will put my car up in the winter and never drive it to work daily.

I know I never said he had a 420a. I was just saying he would have to do a lot of engine rebuilding referring to me. the 420a has a DOHC 2.0 liter and the 4g64 has a 2.4 l SOHC. and as an engine swap goes its a pain in the azz. Seriosly will always be and never easy I dont know a whole lot about the 4g64 but I would think that he would have to swap the tranny out to but then again I would not know. but either way it is a pain in the azz.

You can boost as much as you want as long as you don't knock and as long as your motor can with stand it.
Wow I use (6 as) in that sentence, .

Actually a t28 is larger than the t25, and almost flows as much as a 16g..But spools significantly sooner..Which is a big hit with the autoX guys..On a stock system they work pretty well..I've been in a stock car with a t28 and the injectors kept up fine..But if your going to push boost past 15psi then yes you should get a fuel system upgrade..

ahh crap, i was thinking of a t25... im sorry. thanks for setting me straight )

You were right on thinking the t25 is small..Because it is the smallest turbo that came stock on a dsm..

It's alright man, I'm here to help..And assist if I can..

thanks but i try to give accurate info (unless its just my opinion). i was looking into a stock turbo that would be a good fit with my torque curve and hp goals and the compressor maps along with the things i read about the t25 made me think it wasnt worthy of even a stock 420a build im thinking of a td04hl at 8psi max tuned with msII... have u heard of that combo before? sorry i figured i would ask real quick cause have searched for about 2mnths and havent found anyone that has used that combo or talked about results.

Yeah I have a Spyder, so it was the 4G64 that was in. Its not me who did the swap but it looks nicely done. The guy didn't even know he had to change the ECU and harness, at least thats what I think because the guy said the car needed to be tuned, but it should be fine with the 4G63T Ecu and harness. So I don't think he changed anything on the car beside what I wrote. I'll double check injectors and fuel pump to see if they are really stock but I really think they are.

For the swap, I think that the 4G64 tranny would be fine on a 4G63. However, he swapped both the motor and tranny. So there is no difference between this car and a spyder gs-t right now. I don't know why you say I should rebuild the engine, it is already a turbo engine and has all the required stuff to make it reliable from the factory. If I had the money, space or knowledge to do a complete rebuild, I'd do it, just to make sure the car is in perfect shape. But since I'm not rich and the car is runnning fine, I won't touch any internals. The only thing I plan on maybe changing is the valve cover gasket.

And yeah I'M thinking about a nice reliable summer sports car. I don't plan on buying any other performance parts for this summer, I just want to make this setup perfect and reliable.

NOTE : I have 2 Eclipses. 1 - 1999 Eclipse Spyder GST
2 - 1999 Eclipse Spyder GS (Swapped with a 4G63T)

For the GS, it was missing the ECU and harness so I took the ones from my GST.

For this summer, I wont boost past 15 for sure unless I get enough money for Fuel pump, injectors, exhaust manifold, o2 housing and logging/tuning tool. I just want to know how I can determine if I'm safe running 15 psi.

BTW, I looked on the forum for info about that Ceddy's mod and I don't understand how to use it, is there any guide on the net ?

And what cable do you use ? I read somewhere you can find some for 30$ on ebay, if so, what kind of cable do I need so I can order it ?