I just bought a 96 SOHC neon with 50k miles for as my daily driver for $1k. I am not gonna put a buch of money into the car, no exterior mods, but I'm mechanically competent for any inexpensive engine mods. I just don't know what to do to these cars. The low end SUCKS! What can I do to make the car a better performer? Cam? Does the motor do better with some backpressure, or would a 2.5" straight pipe be better for exhaust. I already have a custom intake. Any and all suggestions would be great.

 

Compare low end output (actual dyno, not butt dyno) to other small engines of the time. The Neon's 2.0L had tons of low end torque compared to most... Mate that with adjustable rate, adjustable camber struts and you'll understand why Neons dominated their classes in SCCA Solo2 racing for so long.

No motor needs backpressure. Backpressure kills power, always. Prove differently, and you'll be known as the man who rewrote modern physics...

On to the fun stuff:

The SOHC muffler is probably the worst part of the entire breathing system. Replacing it with just a factory DOHC muffler has been dynoed at 5 HP. So any decent muffler would be better. A good true straight-through design like the Hooker Max Flow or Dynomax UltraFlow is worth nearly 10 HP on an otherwise stock car.

A cold air intake should be drawing cold air. If it's drawing from the stock location (against the firewall, right above the 800F exhaust manifold), it's not doing what it's supposed to. The Iceman, Kirk, and "ghetto" 3.0L intakes do the job very well.

Upgrading to 2.5" piping (mandrel bent of course, available from Dynomax for $85 or so) is nice, but does absolutely nothing if you keep the stock cat, which is a 2.5" inlet/2.25" outlet with a nasty kink where the d/s O2 sensor is. Vitor (www.neongoodies.net) has dynos on his car showing the difference between the stock piping and the 2.5" piping with the stock cat. There is none...

The stock cat actually flows exceptionally well. Within 5% of other 2.25" outlet aftermarket cats. The real reason to upgrade is for the 2.5" outlet and either a mandrel bend or a flex pipe after the cat to connect to the 2.5" piping. You'd have to weld in an O2 bung, of course... Any brand name universal cat will do.

The stock throttlebody on all MTX's is 49mm, where the stock TB on all ATX's is 52mm. Swapping TB's is a noticeable difference on the butt dyno, mostly because the ATX TB spring is weak and the cable cam profile makes it very fast opening (you can swap parts with the MTX to fix that though, which most people do). The late-90's Jeep 6-cylinder TB's are 55mm (MTX) and 60mm (ATX) and will fit with a little modification. I haven't cut open my SOHC intake manifold yet, but I'm betting it's just like the DOHC, no more than 52mm opening where the TB neck connects to the plenum. So 52mm is plenty big until you go with a better intake manifold.

The '95 is the only non-Magnum SOHC that actually put out 132 HP. In '96, they changed the cam profile to a more commuter/grocery-getter/grandma friendly design (no overlap, no lopey idle) and dropped HP output to 128 or so. The '95 cam is now sold as the Mopar 4HP cam... Crane makes several cams that work fine without having to increase compression - commonly known as the #10 and the #12, for a good 5-10 HP respectively. The bigger Mopar cam (8 HP?) is virtually identical to the 2001 Magnum cam. The 2002-up Magnum cams are not worth much more than the '95 cam. All of those will require an upgrade to the valve springs. The springs for the Magnum head work fine and are cheap. Comp Cams makes a relatively mild cam (#200) that works with the stock valve springs and is worth a good 5 HP or so. From there, there is the Crane "#14" and the Comp Cams #400, both of which will need higher compression pistons to work well. There are bigger cams, but we won't get into it here.

There are a number of headers available. The good ones you'll only find used (Blackdog, Fast Fabs) or special order (R/T Ernie). Short-tube headers offer the least gains, but are easy to install, keep the cat in the stock location (which means most are 50-state legal), and relatively inexpensive. These include the Chikara (virtually no gains), the PaceSetter, the TTI short-tube, and the Mopar header (if you can find one). TTI offers a mid-length tube, only one I've seen in that range, requires cat relocation (not legal in the U.S., technically). Kirk, AFX, and TTI still offer long-tube header which invariably offer the most gains. Of the 3, I'd probably go with the TTI, although the 1.625" primaries would not meet my desired rpm range. Their 4-2-1 collector is the best of the buch, where Kirk and AFX are still both using a dump collector last I looked. For what it's worth, one of the 5 or so naturally aspirated SOHC's that is running in the 13's is using a PaceSetter header. I've got one for now as well.

There's always an underdrive pulley. The "street" versions (keep a/c and p/s) are good for 5HP or so. The "race" (alt only) versions closer to 10 HP.

Mopar PCM's you can pick up used for $150. Requires premium gasoline though. No real peak HP gains, but a much flatter torque curve, mostly bottom end pickup. Your butt won't notice much until you try to switch back to the stocker...

Plenty more to do on top of that... Magnum head swap, modified magnum intake manifold, higher compression pistons and rods, standalone fuel/spark management...

There are also turbo kits. 225 HP on the stock pistons isn't all that bad for $3k or so. More than you'll ever get naturally aspirated... Go to forged internals, upgrade the fuel system, and 350 HP is now commonplace. A few have gone over the 500 HP mark now as well.

Fun, fun, fun...

Best of luck!

 

Your pretty knowledgable, thanks for all the great info Radar. How poorly does the stock exhaust manifold flow? Exhaust is probably my next step after getting rid of steel wheels. As it stands the plans are no cat or mufflers full custom straight pipe setup. If I don't like the sound, will probably use flow40series. Most everything else like TB's cams, etc will be held off until I get it dirt cheap (not feasable to have another buildup car right now I've already got too many toys) Thanks again for the info

 

The stock exhaust manifold doesn't necessarily flow that bad. You can go through and smooth out the casting inside and make sure it's a smidge bigger than the head exhaust ports and it'll flow as well as a Chikara. The big advantage to having a real header is pressure pulse tuning to draw a vacuum in the chamber in a ceratin rpm band. Shorty headers like the PaceSetter are using tertiary and quatenary pulses (weakest useable), where long headers (~42" primaries) are using the much stronger primary pulses. If you're ditching the cat, I'd strongly recommend going with a long-tube header. Blackdog's headers were easily putting on 25+ HP over the stock manifold on even mildly modified engines.

I paid $5 for my ATX TB, including sensors... They usually go for $20-30.

The Flowmaster 40, contrary to the name, does not flow remarkably well. Still better than either stock muffler though. If you get the Camaro-specific model (Flowmaster or otherwise), is fits nicely in the stock location and has that fake dual exhaust look that's so popular on 4-cyliner cars these days... The few people I've known with the 40 like the sound, but a couple have added a glasspack in the channel to quiet it down a tad. I've been very happy with my Hooker, flows the same as a 2.5" straight test pipe on a flowbench...

Any idea what wheels you'll be going with? The 15x7" Kosei K1's are very light and pretty cheap. There are lighter wheels out there, but tend to grow in price exponentially... I went with cheapo wheels from Pep Boys - 14x6", 14 lbs (lighter than the stock alloys), $240 for the set of 4. Nice for now I suppose. The steelies are now dedicated for snow tires.

Don't neglect the suspension either. Struts and springs (or a good true set of coilovers) makes a ton of a difference but will cost to do right. But even just upgrading the sway bars (installing the rear in your case, I'm betting) to stock ACR/RT specs, swapping out to poly suspension bushings, and putting decent summer tires on will spice things up.

Edit: yo, admin, what the heck is wrong with the word "s p i c e"?

 

I'm lookin for some stock looking wheels that are still fairly light and still cheap. I got this car because it looks like a grandma mobile, and the cops won't pull me over in it like they do in my truck (I'm 1 pt away from loosin license). So its still gotta be semi-quiet and blend in...... well maybe I won't let it be quiet, but blend in is necessary. If I go with a new header, it'll definately be long tube. I'm not sure if I wanna invest the money in this car yet or wait till my truck is completely done first. The sway bars are a definate suspension upgrades are a definate as soon as I get the spare money together.