I have a 2003 dodge neon r/t, i have just added a hahn turbo kit to it. It had 120 whp and now it has 215 whp. I am running about 9 to 10 lbs of boost with a boost controller and have had it professionally tuned. I was just wondering what other performance parts i could add to increase the horsepower without blowing the car up. The whole engine is stock and dont know how much deep i want to get into this (by taking the engine out and rebuilding the whole engine with stronger pieces). The exhaust is 2.5 inch diameter, and the high performance ones are only 3 inches, so it would make only a small difference. Any ideas on parts? Thanks.

 

well u r pritty much pushing the limits of the stock block now.... i would say that is all u could do unless u go into a bottom end and head... u could also maybe try small stuff like an intake manifold, or some kind of intake off ur turbo (if u do not have one already) three inch is overkill on the exhaust unless u r going big power.... do u have a cam in the car or is the whole block stock?

 

posibly a throttle body, but it will not give u any real noticable gains, same as the intake prolly

 

The 2003+ R/T models have a stock cam which is roughly equivalent to a crane 12. They stopped the DOHC settup in the last incarnation of the RT and just started putting mild 'racing' SOHCams in instead. I had an 04 R/T, its actually sluggish at lower rpm, starts to become lively from 3k-4k, and then screams to the 6500 redline as if it wants to go much higher. At the 7k rpm limit, it feels like its putting out more 'oomf' than it does at the start of the next gear. Makes me wonder if there's a simple way to disable the rpm limiter, or if it is wise to do so? It also had that characteristic slightly 'rough' idle that racing cams come with. Anyway, the R/T's exhaust & cam & secondary intake settup are where it gets all of its power vs. the stock engine, mostly in the cam itself. I'd replace everything 'else' under the hood before the cam.

 

I would save the money and built the block and turn up the boost. the stock motor can only handle about 250f/lb of torque before boom.

 

I have not done anything to the engine, it is all stock. On the idea of small performance parts, how would it help me by adding a bigger throttle body (right now i have a 49mm) to a 60mm. I know having a bigger opening would allow more air flow but how much? I dont have a cool air intake but I dont think it is worth 250 dollars if it doesnt actually help me. Please continue with the ideas, they are helping me with your experience. THanks

 

I have read that the ideal throttle body width is like 50-55mm. I can't find the link right now, but there's been some pretty in depth testing. you want a certain speed of airflow, not 'just' free & easy breathing.

then again, that might not be true with a turbo.

if you do throttle body, do the connect between it and the intake manifold, and bore out the manifold opening so there's no bottlenecking.

other cheap perf. parts: underdrive pulley, adjustable cam gear, header, hmmm, what else? those would only eek out another 10-15 hp at the wheels really (depending on whether the engine needs its timing adjusted).

might play with ignition timing too, and fuel air mix (that much boost could probably benefit from non-stock fuel injectors/fuel pressure)

hmm, nevermind, i just glanced at your original post and saw that you said it was professionally tuned

nitrous? heh i dunno. you kinda did the main cheap thing to get more power already, most other inexpensive things are just going to nibble at giving a bit more power, nothing dramatic left to gain without spending pretty big. 215whp is rather a lot already, that's around what? 250ish at the engine?

 

Hey everyone,
215 whp is alot but there is always room for more...lol. I have not done a dyno on the motor oalone but a common idea is the loss or in my case gain of 17% from the wheels to crank. I should have about 251 hp to the crank. I have called hahns turbo kit (where i got my kit) and they said that they got a stock engine with their kit to have 250 whp. Now i could get that but i would need a boost controller (which i have) and either use race gas ( 116 octane) or with buying a new computer that will let me play with the timing. The computer that came with the kit only allowed me to play with the airflow ratio. Now the computer is about 400 dollars and I dont know about everyone else, 400 dollars are alot, espcially if it wont give me the extra 35 to 40 whp. Does changing the timing actually give you that much power?
To change the cam, i would need to rip the engine out and I just but the turbo in. And if i would take the engine out, i would upgrade to a 2.4L so i could up the boost. But to do this, it would cost 2 grand for the parts and probably another 2 grand for labor ( I dont have the tools or machinery to do this myself). This is why i want to know there is anything i could add without ripping the engine. With a turbo does a cool air intake add enough whp that the cost would be worth it (if it was you), because i only have a k&n high flow air filter. Thanks for the responses

 

wondering what size intercooler pipin u runing? 2.5? if so the throttle body will help alittle. ur throttle body is accually holding back air going to ur intake... because the reduced size of the whole....

as for ripping the 2.0 out and put a 2.4 in i think that is not a good idea, u already have gone this far, and if u want to up the boost u r a light 3k away of doing it, where swaping a 2.4 in ur car is going to cost in the ball park of 6k, and that would get u
maybe 250whp??? not sure why u would just throw out that money that u put in the car already.... just my thoughts on it...

what kinda computer where u looking at? u may beable to get some hp out of running ms (megasquirt)... i am assuming u r running stock computer??


also i would not really want to push ur luck with a stock block u r looking for 35-40whp more.... that is REALLY pushing it.... if u do not want to go internal engine parts, then go with simple bolt ons, even though u have the biggest bolt on there is in the turbo.... but u could jump the boost up to about 10-12 and see where u r at... but that is REALLY PUSHING the capability of the stock block..

also how many miles r on the car?? overall, and with the turbo hooked up??

 

i have about 65k miles on my car and about 300 miles with the turbo on it. right now i am pushing 10 lbs of boost...espcially in the cold weather (i live in new england area) i forget the name of the computer...i will look for the name and come back with it. As for the computer i am currently using, it was the computer that came with the turbo kit. Also, a very dumb question, the srt-4 had upgrades 1,2,3. are any of those possible to get if i have a turbo in my car now. im not sure what are in the upgrades so they might only be able to be used for the srt4...such as computer...but i still have to ask. As for my my tubing...it is all 2.5 inch with my stock throttle body. if i would add a cool air intake...60 mm throttle body would that add any significant hp that i could even feel. I am currently adding a performance clutch and lighter flywheel. i was using the stock clutch and obviously burnt that thing out within 2 weeks. ...all of a sudden i press the gas and the rpms sky rocket with the car not accelerating...i could have guessed...
on another note...my downpipe and up to the muffler is 2.5 inches still but i want a louder noise...i dont have a cat converter to have less backpressure...im guessing by adding a larger muffler, it will give me a louder noise...i hope i am right...
--also modernperformance has a 2.4 swap... it comes with all the parts from a srt-4...the only thing i would need to do i bore out the cylinders... please check it out...www.modernperformance.com under srt-4...

thanks for the responses