Well for starters it's not really the dsm issue so much as Chrysler.... It's just a dodge neon engine that's not engineered to make power, and has imperfections that dampen it's reliability as well.

Yeah....I blew the shit out of my 420A.....over revved the engine in 3feet of snow going 80. I almost made it to my parking spot. Then I shifted on reverse and looked away. No idea if I burned the rings or blew the head gasket, but honestly. Hated the 420A. Not enough horsepower even with stick shift.

Stock ecu is really what holds it back. Not like I am making crazy Hp N/A but tuning is everything.

Oh. And that was my first stick shift. Never had one before that....

In the car world, you can pick TWO out of three things: Cheap, reliable, and fast. The 420a is very cheap, and very reliable. Theyre just not meant for power. You can make power with anything if you jump through enough hoops, but when you put the 420a next to the legendary 4g63, its easy to say well whats wrong with the 420a why can't it make power.

Thanks for the replies guys and I get what you're saying, but I'm still baffled. It makes no sense that you can mod the hell out of it and still basically have a stock motor. I bought mine 4 years ago and haven't had any major problems with it. A buddy informed me the next day that I wouldn't make power with a 420a and I blew it off. It's fairly quick and fun to drive so I didn't really care because I though it for my wife, so no plans for beefing it up anyway. I have been driving it lately and I decided, as anyone with a "sports" car does, as fun as it is it would be more fun if it was faster. It has some mods, on when I got it, maybe some more would satisfy me thirst however after reading up on it more I became even more determined to find out why it's so slow. Long story short I'm looking for the exact weak spot or spots. Ecm is a trouble area but for that to be a reason to be slow it would have to be programmed to stop the power added by bolt ons, a flaw can be fixed that's why it's called modifying just need to find it. Does anyone know where I can get some in depth info on the 420a or do they have any for me?

Honestly, with the money you'd need to spend to make a 420a have noticeable gains and feel faster you might as well just save the money and look for a gst or gsx. You'll be ahead of the game already with the stock setup. Just my .02

Small displacement naturally aspirated engines take a lot money to make significant gains. Headwork, cams, and an intake and exhaust with runners tuned for high rpm power are needed, then an engine control system to take advantage of the parts.

Horsepower = torque(rpm/5252). In a naturally aspirated engine displacement is the main limit to torque. However, by keeping the same amount of torque at a higher rpm, you can make a lot more horsepower.

On the other hand, most turbo dsm's can make a 20-30% power increase with a few hundred dollars in parts.

And for a second there I thought the 420a was long gone. Someone mentioned cheap, reliable, fast. Funny thing is, they aren't very cheap to fix once they inevitably break which means they really aren't reliable either. The platform was just a failure inside and out. The only good thing I can say is the 99's came with black leather interiors, which makes them worth a second look at auctions and on craigslist.

Thanks again for your respectful participation in this subject, some people are far from that on this forum however in their defense you do have a lot of dump questions. Like I said it's not exactly my car and I never had plans for building it, in fact it has a car seat, but it's a strong motor! It's feels faster than some post describes it should be and that makes me wonder, especially with almost a quarter million miles. Plus I don't like to be told " I can't do something", guess I'm a little hard headed and that's why I going to do extensive research to find anything I can to improve it even though it's already been done I need to see for my self.

Oh yeah one more question for Mr Wiseman Donnie, I like your explanation it made sense to me, no sarcasm I'm serious. Can the same thing be said about a n/t 4g63? If so why is it so much better?

I want to keep this going so if you come across this thread and have some positive info leave it for me. Positive meaning not saying to sell it, my wife and I love the car and if I had it to do again I would pick over a turbo hand down it's a reliable member of the family. I know it slow and will be slow but I still need to check for myself.

Booost it

Over 200k and looking for power? Been rebuilt?

Its an n/a Econo motor, bolt ons do nothing, n/a Honda guys praise an extra 3-10 from proper exhaust manifolds on STOCK motor cars with tuning.

Realize what ya got, don't sell, enjoy the mileage till its gets half a million

Talonman86096 said:

Honestly, with the money you'd need to spend to make a 420a have noticeable gains and feel faster you might as well just save the money and look for a gst or gsx. You'll be ahead of the game already with the stock setup. Just my .02

Click to expand...

A+++++++

Just want to add for the op:

It will take a lot of money like one of the wise men (donniekak)said to make hp with that motor and you will still be unsatisfied. I have only seen those motors make descent power when rebuilt with stronger 9.0:1 forged Pistons ,metal head gasket and then turbocharged.$$$$$$$$$$$$

A n/a 4g63 motor is a better built Japanese four cylinder motor that has been around now for more than 3 decades.
The 4g63 twin cam head design alone is superior to the head design of the dodge n/a 420a motor.

Find yourself a RT motor or a SRT4 motor,harness(if necessary), the inter cooler plumbing, and put it in that bad boy ,guys Have done it in the 420a section. The RT and srt4 420a motors are a dime a dozen on eBay.


The turbocharged twin cam 420a motor in the RT and-the srt4 is built for hp and much superior to the n/a version. Much better head design on the turbocharged 420a vs the n/a 420a.

The RT and srt4 420a motor sells for cheap and are a dime a dozen on eBay. Get the ecu and engine harness as well if necessary. Go check the guys that have done it.

Since you know it's an econo motor then leave it for what it is built for.

You're only going to get the same answers my friend from most of us here.

I checked up on the head, it's design is a big issue seeing as how it is designed for emissions. It causes the air to tumble down to the bottom of the cylinder reducing the emissions at the cost of hp. I have no plans to alter the engine of but I wanted to why I was being told I couldn't, I'm still checking on the issues regardless, and I actually think it may be a crate motor in the car because it kinda looks like it has one of those buttons that changes colors is it runs hot but the kid that sold it to me said it was the original motor

josh_effin_tyre said:

I checked up on the head, it's design is a big issue seeing as how it is designed for emissions. It causes the air to tumble down to the bottom of the cylinder reducing the emissions at the cost of hp. I have no plans to alter the engine of but I wanted to why I was being told I couldn't, I'm still checking on the issues regardless, and I actually think it may be a crate motor in the car because it kinda looks like it has one of those buttons that changes colors is it runs hot but the kid that sold it to me said it was the original motor

Click to expand...

Anytime spent doing n/a mods to this motor will just have you chasing your tail. Waste of your time. Said all I can say glad I could offer some info. Finally I say do the aforementioned stuff or just buy a gst ,they are selling for very cheap ,has very good stock hp and you will be happy and satisfied I promise you. Go test drive one and see for your self.

Bolt ons free up power. Cant free up what isnt there. Theres not much restriction in an engine that makes 130hp.

Where as modern big high hp muscle cars are choked out to get them to pass emissions and to quite them down enough to make every possible consumer happy. Even factory intake pipes have resonators and such because certain customers will buy a 500hp vette and cry about engine noise.

Ay dere dotcha kno calm down I'm just looking for the down fall on the engine. This thread is just seeking info on the motor, I have never encountered something like this b4 its mind blowing and I'm just looking for the reason it's such a terrible motor

josh_effin_tyre said:

Hey guys I have a question for you. Why is a dsm 420a so unresponsive to bolt ons. Don't jump in and start ranting, because I am totally serious and would like a serious answer. I have never in my life seen a motor like this one, every bolt on you can get for it produces the amount of hp that one bolt on does on any motor. Really , diamond star really dropped the ball here! I have been searching online for 3 days and I still don't have an answer so I thought I would ask here with all the wealth of knowledge I figured I could have a understanding of the flaw.

Click to expand...

We are all going by your opening post!

I have a 98 RS that can beat a stock 4g63 no problem... however it is highly modified. Turbo, fmic, wb o2 conversion, intake & exhaust headers and pipes, cams, portfueler... on and on and on... if you want to make at least 4g63 power you need at least a turbo and portfueler setup (including fuel line, pump and pressure reg changes)

it will still be a dog on takoff though... there is no real fix for that... i run low profile 14's which help a bit but the spedo is off because of it.

Yeah I know how to make it fast I was just looking for why it was so slow and unresponsive to bolt on's in the first place. I don't want to do make it fast it's a good car and I don't want to waste my time or money, and possibly run it major problems with it. No offense to anyone who does. While tuning it up I did notice a cat back system for the first time in four years, completing the i/h/e performance upgrades, hence the power that shouldn't have been there. 0-60 is a little under 8 seconds which may be explained by the mods. So much for the theory that it was made on a Wednesday

ya straight bolt-on's really wont do anything for that motor although i do think it is a highly underestimated motor and has potential if you have the time and money to squeeze it out but it's a very reliable daily beater motor.

420A crew! Waoh! I can keep up with stocked 4G63T Eclipse.