420A 420A Slow What can I do?

[MediocreGS_Cam]

Hi guys, I bought this eclipse about 2 years ago for 900 bucks. I did the usual maintenance on it until I got out of HS, now I'm starting to get into putting parts on it. The engine and trans are both original to the car, and have 278k miles on them. so far, I have NGK spark plug wires, a Delphi tech distributor, and a couple days ago I put together a universal intake kit for about 115 bucks. so now it sits like this. any suggestions? Trying to get as much out of it N/T without tearing it down too much.

You must be logged in to view this image or video.

You must be logged in to view this image or video.

You must be logged in to view this image or video.

 

[BLACK'98DSM]

This gets asked quite often here. We have decades of threads to study. Definitely go scroll through the 420A section and read up.

You won't get very far without internal engine modifications and tuning. Most bolt ons are mediocre at best.

If you aren't looking to spend a ton of cash and effort, your next step might be an underdrive pulley. That will free up a little power at the crankshaft. I'm not sure if you can buy them specifically for the 420A anymore but you can use one for the 2nd gen Neons. I purchased mine from Modern Performance years ago.

Also, with 278k miles on the engine, you may be lacking performance from normal wear and tear. I'm sure compression is on the low side and carbon is built up inside the intake.

It gets very repetitive for me to post the same informations over and over so I've left many things out of this post. I encourage you to peruse through the 420A section & articles. There's plenty to be done with the 420A but not everything is cheap and easy. Research is required to make the best of it. Good luck!

 

[curt-s]

This

It's likely a tired engine. 420A never produced much HP and if you consider a loss of 1hp per year, you've already lost nearly 30. Do a compression test to see what you have.

Small displacement NA motors make horsepower with work over time and high compression, so at the least you need high rpm. That's something the stock engine can't do.

Additionally you have to maximize your fresh air intake into the cylinders (where the ecu adds fuel to match) per rev, but under vacuum you can't add more air than the cylinder displacement.. so if your rings aren't sealing great, you have various restrictions around the valves, or you can't get rid of all the old exhaust after combustion, you're falling short.

The last two things get more difficult the older the engine gets because of buildup.

First step, check compression. That will give you an idea of how much HP you can basically restore, if any.

 

[BLACK'98DSM]

It actually takes a lot of work to continue producing usable horsepower above 7500 rpm. The stock rev limiter / fuel cut is at 7200 rpm for this reason. Bare minimum you'd need high lift camshafts, stiff springs with titanium retainers, and properly degreed valve timing by adjustable gears. Oversize valves and port work are necessary for stable and usable power production above 8,000 rpm.

My main purpose for having an 8,200 rpm limit is to sustain the powerband with each shift. Hitting second gear at 6,000 rpm and third gear at 5,200 rpm is the key. No major dip in power delivery and pulls very quickly. I typically shift at or below 7,000 rpm to reduce fuel consumption and engine wear. But if I'm racing competitively or revising the tune, I'll run it to the top.

Adjusting the rev limiter / fuel cut is achieved one of two ways. Either with generic junk like the Bee R or with a standalone like MegaSquirt. There's really no sense in raising your revs unless you can tune though. I've had fun doing so without tuning in the past, but with no way to increase fuel delivery this can be dangerous and won't have the desired result.

All this being said, revving higher is not necessary to have a fairly quick 420A. Last year my 0-60 time was 5.64 seconds, and on this specific pull I shifted at 7,100 rpm from first to second. I have never ran the timer for a pull shifting at 8,200 rpm, but the result BELOW stock fuel cut is already satisfactory.