SOHC Buildup Walkthrough

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infil
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SOHC Buildup

Post by infil » Wed Feb 21, 2007 10:35 pm

Since 90% of my experience is with SOHC's figured I'd have some useful information to contribute.

So you have a SOHC neon and want to build it up. Keep in mind, SOHC's respond better to mods, but generally speaking will not put out the same amount of power as the DOHC plant will, but that, by no means, means they are slow.

The first question you need to ask is what direction do I want to go? Turbo, All Motor, Nitrous, Turbo w/ nitrous, etc.
What level do you want to take the car to. Do you want to maintain street ability? Do you want balls out power and damn street ability?
Once that question is answered, that narrows down the field of what parts you want to run, that won’t be detrimental down the road, and also will let you select parts that you won’t have to remove down the road once you get further into your build.

All Motor:
Most people think all motor is the cheapest way to build a neon, which, to a point is true. For bolt-ons etc, it is by far the cheapest up front, however as time goes on and you want more and more power, you can invest enough to buy a second, and in some cases a third car. This IS however the best options for the daily driver/strip/autox car, as it’s much easier to stage upgrades, and keep power output to a manageable level.

The big things to focus on in an all motor buildup are:
Compression. You will need compression to be competitive. Anything from a DOHC bottom end which will put you around 10.2:1 I believe, to custom pistons as high as 13.5:1 or higher depending on how much you want to spend and if you plan on keeping it on the street or not.

Cam. The cam choices we have are severely limited due to the construction of our heads. Instead of the traditional cam cap setup, we have solid cam journals machined into the bulkheads on the head, and they are pretty restrictive on cam lobe sizing. There are ways around this, such as lowered lobe centers and lash caps which is used effectively on only the largest SOHC cam(crane 15, haven't heard of the official designation for it, but its .400/.400 lift, and 232duration@.050 lift on both sides). Some other methods have been tried with limited results, and the results usually were not real reliable for street cars.

Along with the cam, a good port and polish job is essential. There is a plethora of companies that will do port work and I leave the decision up to you. I personally prefer Howell Automotives work, but some other options are NRGY heads and Protuning.com, however Howell’s work is done by the best in the business of custom neon work. The most power will be found from a port and polished Magnum Cylinder head, which bone stock flows as much air as a race ported non magnum SOHC head. Also consider thermal coatings on the valves, and ports as this will again, increase power, reduce heat retention in the engine, and increase overall engine life. A good porting job will include at minimum, port matching services, casting flash removal, and balancing the ports. An extreme porting job will go as far as 5angle valve jobs, complete bowl and chamber reshaping, unshrouding the valves along the fire deck, removing valve guide protrusions into the ports, and numerous other services that will pretty much depend on where you go for your headwork. This is one of those things; I strongly recommend that you have this professionally done, as it is incredibly easy to destroy a head. The goal in porting a head is to remove the absolute minimum amount of material to achieve maximum flow and velocity, while maintaining pressure. Without flow the car doesn’t run, without velocity you will have horrid power, and without pressure, you will not maintain much of a mixture. A good intake port will have a rough finish promoting swirl, but not so rough that it promotes pooling, and a good exhaust port will be like a mirror.

Now you’re probably thinking great, the head is flowing like the Suez Canal, how do I get all that air to the head?
The Intake side leaves us SOHC guys with a few options. The Magnum intake manfiold (01+ S4RE Magnum Motor) is a very good active intake, using a dual runner design making for a very broad and useable power band. To install this manifold on a non magnum car, there is some wiring that needs to be done to allow the butterflies to function, or there is the option of removing them all together, this does however require a good bit of fabrication and is not for the weekend mechanic. The other option is the Indy Intake manifold, which is also an awesome piece, netting gains of 25hp on a dohc with minimal bolt ons(intake, header, computer) and around 19 lb ft of torque on the same DOHC. SOHC gains are similar and also as impressive.
The other option, which is the most expensive, would be Individual Throttle Bodies, which can run anywhere from 800-3500 depending on how it is set up, and will net the most power, unless you have a very application specific plenum manifold built, and when I say specific, I mean purpose built specifically for your car, based on flow from your head, compression, fuel maps etc. Either of these options will be very expensive, and very worth the power you will see from them. These options are also, NOT, and I cannot emphasize this enough, NOT any where close to street friendly. They can be driven on the street, but it is not for the faint of heart. At this stage on the intake side, your throttle is an on/off switch or damn close to it.

The exhaust side is just as critical as the intake, if not more so. There is allot of controversy over which header is the best, so let me put it like this.
For maximum power, a stepped long tube design will net the most gains. Collectors will be something to be discussed with the person building the header if it is a custom header as the collector is critical to header performance. For off the shelf units, Pacesetter and Mopar both have very good short tube designs, TTI makes a very innovative medium tube design with AF/x, and Kirk making non vaporware long tube designs. The Kirk is the mildest of the long tubes, using the smallest primaries and the smallest outlet of the three, netting impressive gains over stock, but not the maximum gains to be had. Long tubes are where the balls out power comes from. As the stock sohc manifold breathes like an emphysemas chain smoker trying to suck a golf ball through a garden hose, ANYTHING is an improvement over it. The Magnum stock manifold is a very good piece for a budget car; however it will require modification to fit a first gen car, or a non magnum motor.

The rest of the exhaust is pretty straight forward, 2.5" piping has proven to be the best overall for the 2.0L platform, with a straight through muffler and solid 2.5" catalytic converter. 3" is simply too much for a naturally aspirated motor, until you are pushing the limits of what the engine is capable of producing. Dynatech makes a very high quality bullet style catalytic converter in stainless that will tuck into the tunnel on the end of a long tube without any tunnel/cat modification. Random Technologies also makes cats that will fit, however they are extremely expensive. With lowered cars, you can get a catco to fit, however ground clearance is a serious problem. On my coilovers, I have completely ripped off 2 exhaust systems at the cat. Basically keep in mind your cars ride height and make adequate provisions to clear the cat. For short tube headers dynomax makes a very good unit, as do magnaflow, catco, and numerous other companies.

Basically put, all motor’s main expense along from the specialized nature of the parts at the higher power levels comes from extreme maintenance and regular catastrophic failures, but if stuff isn’t breaking, you’re not pushing the envelope hard enough.

Turbo:
Turbo Setups will benefit from porting and polishing as well, however the big gains with a turbo are going to be seen in the turbo itself, and in building a motor to handle the increased cylinder pressures associated with turbocharged motors. Stock compression or less is the norm, with increased compression being possible, but requiring a bit more than most people are willing to spend.
Cam selection again is very important, as the right cam cut turbo lag in half, and the wrong cam can double it, or worse. Another big thing to think about is fuel. Too much fuel, while still detrimental, is much more desirable than a lack of fuel. On a turbo motor, a lack of fuel means broken parts, too much fuel, means a puddle on the ground under the tail pipe.
The Hahn Racecraft turbo kits are very complete, and the Chill Factory is releasing upgrade parts for the HRC kits at a surprisingly fast rate, as well as their own turbo kits which are absolutely phenomenal. Having seen a few of these parts in person, they are top of the line parts.

Ignition will be a concern as you will want to retard timing with a turbo kit, to prevent detonation under boost. The Crane Hi6-Di2 is a very solid unit, as is the MSD DIS2. The crane IMO is a stronger unit, but it is a bit more expensive, but does offer greater flexibility using cranes modular system.

The exhaust side of a turbo can make worlds of difference in how well the turbo works. A large downpipe, such as the chill factory 3" piece, makes for a huge gain, and a complete 3" exhaust should be considered standard equipment for a turbo car. The harder the turbo has to work to overcome exhaust backpressure, the less boost you have available and the less power you have. Too much backpressure will also cause the air in the turbine section of the turbo to cavitate, causing all kinds of nasty things, compressor surge being the worst as this spikes boost and causes internal engine components to break, lack of boost would be the other end of the spectrum where you just get minimal boost out of the turbo. This is also detrimental to the turbo as the bearings take allot of abuse from cavitation.

Water-cooling the turbocharger is another way to get a descent amount of power, but more importantly reliability out of the unit. This simply takes the engines cooling system and routes it to the turbo charger for increased cooling, extending the life of the turbo. A turbo timer is also something that should be considered mandatory as when you shut the car down, this leaves the engine running to allow the turbo to spin down, and allows the turbo to cool off a bit before it shuts down.
Boost controllers are nice to have, I prefer mechanical units, with the Greddy ProfecB being the only electronic boost controller I have not had any problems with on the electronic side. Mechanical will always be cheaper and generally speaking more reliable as well.

Nitrous:
Nitrous acts as an air quality aid basically. It increases the oxygen content of the ambient air, allowing for more heat to be generated and as a result, more power. Nitrous however is not a magic bottle that will make you run 10's. It deserves the highest amount of respect out of anything you can do to your car because an improper nitrous setup can literally destroy your engine in a matter of seconds. You NEED allot of fuel being injected with nitrous for it to function properly.

All in all, nitrous does have a bad reputation for little reason. Set up properly nitrous will be just as safe as any other modification you make, I can not stress enough, that using nitrous on the street is suicide. It is for use in a controlled environment ONLY and is not something to be taken lightly. (sorry, had a major nitrous malfunction damn near kill me at the strip, I’m a little anal about the responsible side of it hehe)
Things to consider with nitrous are compression. You can run more timing and less compression, less timing and less compression, or a small shot with more compression and more timing. There are variations of this, and type of system will have a large effect in how you run it. I believe in one of the other lounges there is a very good nitrous FAQ which should answer most of your questions on it.
Other things to consider are items like purge kits, bottle heaters and a nitrous pressure gauge. These will let you keep your bottle pressure consistent and the lines full of nitrous which will increase your consistency. Along those lines, a nitrous controller will also be a huge help in keeping consistently, but a controller is an expensive piece of hardware.

Final Notes
There are plenty of ways to run with your SOHC project. Nitrous and turbo combinations can be ruthless at the track, but pretty much kills reliability and engine durability.

All in all, Durability is determined by the quality of the build. If the engine is built properly, and is maintained properly, it will last for a very long time. Things like turbo timers, water injection, increased cooling capacity for both antifreeze AND motor oil will add thousands of miles to a motor, and will also net a few more horses, along with things like using high quality oils and lubricants, spark plugs, filters etc are simple things that will greatly extend the life of the engine, however I am VERY against oil and fuel additives for a few reasons. Oil is developed with certain additive packages which are designed to squeeze the maximum performance out of the oil. Things like Zmax, Prolong, Duralube etc add their own blend of additives which in tests done when I was in school both at the school and at Titan Oil’s Denver processing plant showed the effects of a couple off the shelf additives and it was impressive to say the least. The additives when mixed with oil and heated to operating temp actually caused extremely accelerated bearing wear and deformation. This is with no friction being generated. Coolant additives however can be extremely beneficial. Many ethylene glycol coolants are a careful balance of some quite corrosive chemicals. Redlines Water Wetter is an additive that I have used for years and had excellent luck with. I have noticed cooler temperatures (about 10-12 degrees cooler with a 50/50 winter mix, and around 15-18 degrees cooler in summer with a 70(water)/30(antifreeze) mixture.
My personal recommendations for plugs and fluids are:
Redline 0w30 Motor Oil or Mobil1 5w30 motor oil
K&N filters exclusively – hands down their best.
Mopar gear lube (ATF+4 for my pt transmission)
Prestone Antifreeze w/ Redline Water Wetter, and ALWAYS use distilled water for your cooling system.
NGK Spark Plugs (I currently use BKR6ES, but will be trying out iridium on the dyno later this year as a favor to a friend at NGK and a local distributor)
Crane Sparkplug Wires simply because they generate the lowest external magnetic field with the highest output of any wire I have run with the exception of Taylor 10mm Kevlar jacketed ProMag wires at about $600 for a big block Chevy set.
Sunoco Fuels are the best however they are limited in availability; VP is another very good racing fuel, for street use, avoid Bradley. I know Gulf, Conoco and Shell all have overall high quality gasoline and usually offer higher octane’s than the typical 91(highest octane 99% of the pumps have in Colorado)

Things to avoid:
Pennzoil like the plague.
Flag or other store brand anti freezes. Radiator stop leaks are also bad bad. If you have a leak, fix it. Bars Leaks is going to create more problems down the road.
Miracle fuel/oil additives. There are some good ones out there for running every 50-100k miles, such as BG44k, and Mopar Combustion Chamber Cleaner, which are both excellent products when used in moderation, however they can do more harm than good when used to excess.
Designer spark plugs, Bosch +2/+4, the Zex 3 electrode plugs etc, are not going to up your power, in fact they will probably hurt it. When running a motor with a denser mixture and when you need more firing power, platinum/silver/iridium plugs become quire useful, however at this time, I stick with good ol’ single electrode plugs. I’ll let you know how the iridium’s do on the dyno.

Good luck
Infil <--click
AMSOIL, Technical Auto Group, S.I. J&V Tools
Fast Times Performance 2002 Subaru WRX 2.5, 11.936@113.18
95 All Motor Neon
13.958@96.99
SOHC - ALL MOTOR - STOCK BLOCK

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das2123
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Post by das2123 » Wed Mar 14, 2007 2:56 pm

Why did you not mention anything about the Magnum cam for our SOHC? It's a cheaper upgrade and worked nicely on my 97.
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infil
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Post by infil » Sat Mar 17, 2007 11:23 pm

please note, this was written over 3 eyars ago, i have tried to keep it up to date but i'm sure there are vendors no longer around, and parts that are no longer made that are refrenced. Any questions feel free to PM.
Infil <--click
AMSOIL, Technical Auto Group, S.I. J&V Tools
Fast Times Performance 2002 Subaru WRX 2.5, 11.936@113.18
95 All Motor Neon
13.958@96.99
SOHC - ALL MOTOR - STOCK BLOCK

DefEddie
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re

Post by DefEddie » Sun May 27, 2007 11:39 pm

More info on the magnum cam?

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Lackof
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Re: SOHC Buildup

Post by Lackof » Mon May 28, 2007 12:39 am

infil wrote:I personally prefer Howell Automotives work, but some other options are NRGY heads and Protuning.com, however Howell’s work is done by the best in the business of custom neon work.
NRGY is not in business anymore as far as porting from what i know.
infil wrote:An extreme porting job will go as far as 5angle valve jobs, complete bowl and chamber reshaping, unshrouding the valves along the fire deck, removing valve guide protrusions into the ports, and numerous other services that will pretty much depend on where you go for your headwork.
For N/A, at least on a neon, 3 angle is as far as you probably will need to go.
infil wrote:The rest of the exhaust is pretty straight forward, 2.5" piping has proven to be the best overall for the 2.0L platform, with a straight through muffler and solid 2.5" catalytic converter.
Basically put, all motor’s main expense along from the specialized nature of the parts at the higher power levels comes from extreme maintenance and regular catastrophic failures, but if stuff isn’t breaking, you’re not pushing the envelope hard enough.
Here is a good exahust setup for 2.5" all around...
http://ttiexhaust.com/Neon/Exhaust.htm#NeonExhaust

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Re: re

Post by das2123 » Tue May 29, 2007 9:18 am

DefEddie wrote:More info on the magnum cam?
The magnum cam from the 2nd gen R/T's and ACR's are a more agressive cam and swap right in the 1st gen along with the Magnum springs.
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Post by Tyler » Tue May 29, 2007 11:58 am

Word, magnum springs FTW!!
97 sohc- 'Victoria'
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Post by chipdogg » Tue May 29, 2007 4:37 pm

Lol, screw SOHC. Go 2.4. Can go just as fast for much cheaper! :lol:

Good write-up tho for the SOHC guys. :)
'97 black ACR coupe- #3 - Scrappy
'96 black coupe- #4
'97 magenta coupe- #10 - 13.379 @ 101.07 mph
'04 SXT mtx - #45 - GF's DD
'96 ACR
'95 Astro Van
'11 Chevy Express
'02 atx - #48
'98 Intense Blue R/T - #49
'04 SRT-4 - #50
'99 Intense Blue R/T - #51

52 and counting, when will it stop?

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das2123
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Post by das2123 » Tue May 29, 2007 4:46 pm

chipdogg wrote:Lol, screw SOHC. Go 2.4. Can go just as fast for much cheaper! :lol:
But we like P/S and A/C :lol:
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Post by chipdogg » Tue May 29, 2007 5:08 pm

Pfff, I took that out of all my Neons that came with it, even my SOHC. :lol:
'97 black ACR coupe- #3 - Scrappy
'96 black coupe- #4
'97 magenta coupe- #10 - 13.379 @ 101.07 mph
'04 SXT mtx - #45 - GF's DD
'96 ACR
'95 Astro Van
'11 Chevy Express
'02 atx - #48
'98 Intense Blue R/T - #49
'04 SRT-4 - #50
'99 Intense Blue R/T - #51

52 and counting, when will it stop?

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Post by SPARKZ » Wed Apr 09, 2008 6:22 am

What about a crane camm for the sohc ?? is it better than a magnum camm and which magnum springs fitt the sohc as in year or part number im rebuilding a head as we spaek i need info fast please
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