Spyder Questions for DOHC swap & Turbo in 98 Spyder GS

[Potmus63t]

First and foremost, I've spent the last 4-5 months familiarizing myself with what little I know about this platform. I am following a typical build path for the 4g64 that is in my 98 Eclipse Spyder GS, which is a 4g63 DOHC swap, and turbocharging it. I know there are a lot of posts related to this, with several actually being informative. That being said I'll be as detailed as possible asking what I'm still unclear on so far. I'll also lay out my current plans which are as follows.

1998 Eclipse Spyder GS (4g64 SOHC)

Rebuilt to stock 2g 4g63 Head (1995) with stock camshafts
4g63 adjustable Cam Gears
1994 Galant DOHC 4g64 Timing Belt
All new 4g63 Timing components (auto hydraulic tensioner, tensioner pulley, idler pulley)
2g 4g63 Intake manifold (inlet ported to accept 1g 4g63 Throttle Body)
1g 60mm Throttle Body
2g 4g63 coil pack
1g 4g63 Cam Position Sensor (and wiring harness to run the 1g cam sensor on a 2g)
2g 4g63 Fuel Rail w/ factory regulator
2g DOHC Cam Cover
2g 4g63 Water Pipe
2g 4g63 Thermostat Housing
2g 4g63 turbo Oil Pan (and turbo to oil pan return line)
2g 4g63 Water Pump
New Mishimoto Radiator (and new upper/lower hoses, and thermostat)
Manley 8.5 CR Pistons
Eagle 150mm Connecting Rods
EVO3 16G Turbocharger (exhaust inlet ported to remove lip and open up to wastegate)
2g 4g63 Exhaust manifold and o2 housing
CXRacing 3" Intercooler & Piping
190 LPH Fuel pump
CCDesign 3" Exhaust (downpipe to tailpipe, Test pipe, muffler)
All new gaskets and seals for the above
ACT Flywheel
ACT Clutch
1995 4g63 ECU (socketed already for ECMLink)

I have the majority of the above, but not all of it yet (Pistons, Rods, Exhaust, Radiator, ECMLink, Clutch, Flywheel)

My goals aren't glamorous at all. I'm shooting for no real number. I've mentioned 275 in the past, but ideally, I'd like to run low enough boost to keep this vehicle reliable for weekend drives, but high enough to prevent excessive boost creep. This car will NEVER be launched or raced.

SO hopefully that enough background for where I'm headed with this car. Here are a few questions I'm unsure of at the moment despite spending hours searching for specifically.

Questions:

Injectors. I have on hand reman 450cc Injectors, and the resistor pack to convert over to Low Impedance to run them. I got these before I learned of the possible limitations with fuel cut running the turbo I have. I've found several threads that recommend moving up to 650cc injectors, mentioning I shouldn't hit any fuel cutoff with them. My question is, should I stick with the High Impedance injectors and just disregard the resistor pack, or should I stay with the Low Impedance? I'm under the assumption my current ECU is looking for High Z, but when I swap over the ECU, it would be looking for Low Z. Maybe I'm over thinking it, and it doesn't matter one way or the other. I'm just wondering if there is a difference between the two when I run the new ECU with ECMLink or any setting that may need to be changed because of it.

Timing covers. I've read conflicting information regarding what I need. I understand some people run without ANY timing covers, however I'm a bit paranoid a rock will kick up and land where it shouldn't. I've read that you need ALL 2g 4g63 timing covers, I've read you need the 64 lower and the 63 mid and upper, and I've also read that the 64 lower cover can be modified to use after the DOHC swap, but can't find any info on the modification. Anyone know which is correct?

Transmission. I have the 5 speed manual in my car. I plan on upgrading the clutch w/TOB, and using a lightweight flywheel. My understanding is they bolt up just fine (the ones for the 4g63 5 speed trans). As I said, this will never be launched. I know the gearing is slightly different from the 4g63 5 speed trans, but how well can it hold up to daily driving with the increased torque? Should I run it until it fails? Should I look into a 4g63 trans and axles? If I go that route, do the hubs need to be replaced as well (I know the spline count is different at the trans).

Turbo Cooling. I know the 2g turbo coolant feed is off the block, but I was considering feeding it from the turbo thermostat I have, then returning it to the water pipe. I know some don't even run cooling to this turbo, and just let it cool off before shutdown, but I'd rather use the ports available and send some coolant through it. Anyone foresee any issues running it they way I described? It will be high pressure to low pressure so I am thinking it should work just fine, but I'm not an expert on the subject so looking for advice from those who know better.


Those are my questions at the moment. Things I haven't been able to find or haven't been answered clearly. Any advice, suggestions, or help is appreciated. If you need any additional clarification on anything cause I didn't share it above, please feel free to ask. Appreciate it.

 

[Father and Son DSM]

Thanks for making this post! I"m attempting to do the same thing, basically, also on a '98 Spyder. I'm surprised that no-one replied? Either way, thank you for posting this, as even your list above is tremendously helpful to me. Did you end up completing everything, and were you able to answer these questions above? I'd love to hear how it went, and what you learned. I'm in NC. Thank you, Daniel

 

[Potmus63t]

Currently just have to get ECMLink, wire in knock sensor, turbo ECU, and do the fuel pump rewire mod. My plan is to have it done by summer and start fixing any issues that come up and then tune.

 

[Potmus63t]

Thanks for making this post! I"m attempting to do the same thing, basically, also on a '98 Spyder. I'm surprised that no-one replied? Either way, thank you for posting this, as even your list above is tremendously helpful to me. Did you end up completing everything, and were you able to answer these questions above? I'd love to hear how it went, and what you learned. I'm in NC. Thank you, Daniel

I’ve figured out or found answers over the months to the questions I’ve asked above.

1. Doesn’t matter which type (high or low) you run, but you need to use a resistor pack to run the low impedance.
2. I saw no way to run the 4g64 lower timing cover. I was able to find a used 4g63 cover, which is a hard to find part at the moment. I am not running a middle or upper timing cover.
3. The 5-speed transmission has different gearing, but it also isn’t built as strong as the F5M33 transmission that comes with the gst. I was told it will hold up for a time, assuming I take it easy on it. If/when I DO go to the F5M33 transmission, all I would need are the gst axles as well. The spline count going into the transmission is different between the gst and spyder gs axles, but it is the same at the hubs.
4. I DID run my turbo coolant supply from the thermostat housing. I found a thread or a website a few months ago that showed exactly that and they had good results. Key thing being a higher pressure area to a lower pressure area. You don’t get much lower pressure than a return to the water pipe (which supplies the water pump with coolant to pump). That being said, many people aren’t even running coolant to their E3 16g turbos. So even if this was a ‘non optimal’ routing, there would be no harm from it as long as I let the car run for a minute at idle before shutting it down.

There are a few more things that weren’t mentioned above, and more work that I’ve done since the original post, but, I still have that same wiring to do soon.
-wire knock sensor (just got the harness side pigtail)
-do fuel pump rewire (have the wiring kit ready)
-do the fuel relay bypass wiring
-install turbo ECU (has ECMLink chip in now)

At that point I’ll be ready to send power to the ECU and do some initial configurations to the ECU and give it a first start.

 

[CKOPOCT]

I wouldn't recommend running without timing covers. I've started too many cars and heard birds fly out or cats scream, seen too many squirrel nests in air boxes, etc. The likelihood of any of that happening, or having oil or water get on the belt, is remote. But one stray stick can cause all manner of problems. Never mind the personal injury part...

You can check car-part.com for timing covers. You can also ask @dacowgod (RixRacing) as he has a massive inventory. You can also post a wanted ad in the classifieds. My $.02.

 

[Potmus63t]

I’ve weighed the options when it comes to it. I settled on just having the lower. I know Ricky has many parts, but I inquired about covers previously and he didn’t have any (at least at the time).

This car is garage kept, and with the lack of using it, the hood will be popped for inspection before it’s driven each time. Yes…crazy I know. But it will sit more than anything. It will only be driven on weekends/random days with good weather. I’m not too worried about pests/rodents. If a stick or rock can manage its way past everything to make it into the top of the lower cover…then so be it.

But I do appreciate the advice.