Hello all!
I am a new member and have been slowing preparing to build up my 99 rs. I am looking at dropping a turbo on my 420a but the issue is coming towards the after market catback exhaust.

This is the catback that I am looking at: http://andysautosport.com/mitsubishi/1995_1999_eclipse/performance/exhaust/exhaust_systems/megan_racing/mega00087861.html

The issue I am having is that I want to prepare for the turbo system but am not sure if I should hold off putting the exhaust on until the turbo system is ready to go. I don't want to buy parts twice if I don't have too. Will this cat back work without the added back pressure for velocity from the turbo?

Thanks,
RomulusDSM

First, pay attention to what section you are posting in. Familiarize yourself with the forum layout and introduce yourself in the appropriate section.

Hold off on the exhaust until you install the Turbo kit. The only significant change by installing one now will be the sound. Plenty of people have installed 3" systems while non Turbo. Might kill some low end power though. Up to you how you want to allocate your funds. 2.5" systems work on Turbo applications just fine.

Sorry about that. Didn't understand the forum setup until after I had posted. Thanks for the response. Right now I have an aem short ram intake as my only other mod on the car right now. Wouldn't the power loss in the low end still be negligible? I still don't completely understand the whole theory about how forced induction systems work. To my understanding right now even with out a turbo the short ram should still be providing enough velocity to compensate for the pressure/velocity difference. Is there something that I am missing?

Intakes are not providing velocity. All it is doing is allowing the engine to breathe better. Think of breathing through a straw. Then give yourself a larger diameter straw. Feel the difference? Rather simple analogy there, but you get the point.

As for turbocharging basics, before you commit funds to the project, buy and read this book: http://www.amazon.com/Turbo-Real-World-High-Performance-Turbocharger-Systems/dp/1932494294/ref=sr_1_2?s=books&ie=UTF8&qid=1339628036&sr=1-2

It will break down the fundamentals very well and you will be better off than many other "tuners" that slap an ebay turbo kit on their car. I have a copy that is old and re-read many many times for years as I have referenced it often.

Mods for the your non-turbo setup do not provide any significant dollar to HP increase. So the bottom line is if you want to go turbo, save the money and put it toward buying or piecing your kit together.

Ok, that makes more sense. I had assumed that the engine breathing better would have also produced more exhaust gases. All though since you pointed that out it doesn't make that much more sense. Thanks for the book recommendation. I am ordering it as soon as I get off work.

I found this link while doing some research:
http://www.racetep.com/turbomatrix.pdf

I had previously talked with other DSM owners around my area and they had suggested going with the 16b?. I was looking at dropping in a Greddy 20g and only running at about 6 psi on stock internals and only 2.0l of displacement. Thats why I was looking at the 3" setup for the exhaust.

Would it still be any recommended to go with the 2.5"?

If you are new to all this (i'm relatively new myself), your best bet and simplest install by far will be to install an off-the-shelf turbo kit (Star or HRC). If you go this route, the downpipe will be setup for 2.5" exhaust so unless you plan on fabricating a 3" downpipe from the turbo to your 3" catback exhaust, you probably won't see much benefit from getting a 3" catback. It's also more of a challenge to route the thicker 3" piping (may not be able to go above the rear axle).

3" cat backs are not an issue. They fit fine.

The only issue for the off the shelf kits is the cost otherwise I would just do that.. I am shooting for 1300 and 2000 max. I would like to at least piece together a stage 2 system. I will start looking at 2.5" setup then. Would there be any other potential issues with piecing together a turbo kit to match the exhaust setup?

If you are piecing together a turbo kit, it will depend on what you can find/build for a downpipe, 2.5" should be fairly easy to match up though.

Originally posted by romulusdsm
The only issue for the off the shelf kits is the cost otherwise I would just do that.. I am shooting for 1300 and 2000 max. I would like to at least piece together a stage 2 system. I will start looking at 2.5" setup then. Would there be any other potential issues with piecing together a turbo kit to match the exhaust setup?

I think you are focusing too much on little details at this point. All off the shelf 3" exhausts have a neck-down at the point where it bolts to the factory catalytic converter so it will mate to OEM midpipe/downpipe sections. So with that in mind, an off the shelf turbo kit with a pre-fab downpipe will bolt on as long as it was designed around your intended platform.

As for piecing together a kit, you need a DP fabbed for you at a local place or if you know a welder, otherwise look for a used kit that includes the DP for a 420a Eclipse.

I will probably have a Star Downpipe for sale one I get my 3" DP made. Note that this has a 5-bolt t3/t4 flange.

Before you start piecing together a kit though, you need to decide a few things... First thing should be a power (HP/TQ) goal. Then based on that, you can determine which turbos are potential options. The turbo will then determine what type of wastegate (if not included internally), exhaust manifold, downpipe flange, and intercooler pipping size you will need. After that, most of the other items you need should work with any system (ie. fuel pump, injectors, fuel management, intercooler, blowoff valve, etc.).

The goal is 300~ hp and around the same for torque. So I guess? I am looking for a 150ish hp~ gain from the turbo but I am not exactly sure how to check sizing for that. I would prefer the Bov open to the atmosphere. That is just a personal preference though. :)

Originally posted by romulusdsm
The goal is 300~ hp and around the same for torque. So I guess? I am looking for a 150ish hp~ gain from the turbo but I am not exactly sure how to check sizing for that. I would prefer the Bov open to the atmosphere. That is just a personal preference though. :)

The book I showed explains how to select your system.

Okay. Thanks I got it ordered late last night not sure when it will ship though. I appreciate the help. I guess in the mean time i will be looking at doing suspension work. I already have al the parts picked out just got to do the damn saving to get 'em.

This is what I am looking at:

RM Sway bars
Tokico Illuminas 5-way on the front and the rear
Megan Racing Springs
Camber kit

Thanks again for all the help.

I had this same exhasut system for my gs-t. It has a nice deep tone and looks good. Megan Racing is a good company. I have ordered a few products from them and always recieved them in a few days.

Originally posted by romulusdsm
Okay. Thanks I got it ordered late last night not sure when it will ship though. I appreciate the help. I guess in the mean time i will be looking at doing suspension work. I already have al the parts picked out just got to do the damn saving to get 'em. This is what I am looking at: RM Sway bars Tokico Illuminas 5-way on the front and the rear Megan Racing Springs Camber kit Thanks again for all the help.

I'm not trying to sway you from your decision, or the platform, but between the exhaust, that pile of parts, and the sale value of your car, you could have a factory turbo model.

Selling all that stuff he has would be a ton of work!.. The only upside the turbo model has over ours is the motor. While we are rebuilding motors, they are rebuilding transmissions. (They can only handle around 300whp before they grenade) I would stick with the 420a.
(Trust me when I say selling stuff and starting all over gets you further away from your goals.)

Originally posted by fast420a83
While we are rebuilding motors, they are rebuilding transmissions. (They can only handle around 300whp before they grenade)

Negative ghostrider. Stop spreading hearsay.

Originally posted by fast420a83
Selling all that stuff he has would be a ton of work!

Re-read OP's post. That parts list is a wish list right now. Just saying consider all alternatives with the final 300-ish number in mind.

I guess my old Import Tuner mag is wrong.. My bad. That doesn't makes a lot of sense.. From other people I heard this from too. I'll have to call Shep Trans to confirm.

With the final 300 number in mind. All the motor needs is forged pistons and rods to handle this.. Lets say $700 on that. Then a piece together turbo kit can be made to reach the 300whp mark for around $1,000, Finally a megasquirt setup for $400-$500.. So we are talking $2,500 total... He might get $2,000 for his GS. Which he will have to sell to purchase a GST for $4,000 (a decent one) Then he will need to sink $1,000 plus to reach 300 on the GST.....So all together if he stays with the 420a it will only cost him $2,500. Compared to $3,000 or more, and the hassle of selling his old whip and finding a new one!

Originally posted by fast420a83
With the final 300 number in mind. All the motor needs is forged pistons and rods to handle this.. Lets say $700 on that. Then a piece together turbo kit can be made to reach the 300whp mark for around $1,000, Finally a megasquirt setup for $400-$500.. So we are talking $2,500 total... He might get $2,000 for his GS. Which he will have to sell to purchase a GST for $4,000 (a decent one) Then he will need to sink $1,000 plus to reach 300 on the GST.....So all together if he stays with the 420a it will only cost him $2,500. Compared to $3,000 or more, and the hassle of selling his old whip and finding a new one!

Learn to post once to answer/reply to threads. It is unnecessary for you post multiple, subsequent posts.

My bad, I am on a crappy phone that wont alow me to highlight and paste. I will be aware of that in the future.