Thread: Se-r 101

List member Kurt Sussman is planning to build, test and manufacture a short runner intake manifold. When running computer simulations with Dynomation’s software, gains of up to 15 hp above 5000 rpm with losses of only 2-3 hp below 3000 were noted. This seems to indicate that Nissan sacrificed lots of top end power to gain a little below when designing the manifold. I noted that Nismo’s race manifold as well as GReddy and JUN’s race manifolds have short runners. The 196hp SR20VVL also has a short runner manifold. As these manifolds are designed for the RWD S13 and S14 chassis, Kurt took it upon himself to design one for the FWD cars. Yeah Kurt! We will be posting the results of this manifold as Kurt get around to it. However, he just had a baby girl which should postpone his manifold development for quite a while. If anyone else wants to do it, let me know!


Extrude Honing

Extrude Honing is a process where an abrasive putty is forced through your manifold or other difficult to port areas at a high velocity, removing material. Extrude Honing is great because it can port areas where it is otherwise impossible to do so, like in the middle of your very long runner manifold or deep inside your manifold's plenum chamber. Extrude honing is also very good at equalizing manifold runner flow.

Smaller more restrictive areas in the head act like a venturi so the putty flows faster there. Faster flow equals more cutting action and thus the Extrude Honing process by nature removes material where it's needed the most. This cutting mechanism is very good at producing runners that flow equally.

We tried Extrude Honing the manifold on project SE-R. This is the shorter runner manifold for the low port, post '93 head. The end results were mixed. Although the Extrude Honing performed extremely well on the flow bench, as the folks at Extrude Hone said it would, the dyno tested power increase was minimal.

On the flow bench the Extrude Honed manifold flowed a whopping 15% more than the stock manifold. Runner to runner flow which varied by about 13-14 cfm per runner stock had the variance cut down to less than 1 cfm per runner. With these excellent results we eagerly bolted on the manifold. By a SOTP evaluation, it was thought that the manifold improved throttle response and top end power. When the manifold was dynoed, the results were disappointing as the motor only gained one peak hp while losing one hp below 5000 rpm. Past the power peak until the fuel cut, the motor gained 3-4 hp. Although these gains seem small, they were repeatable through 4 back to back dyno pulls.

This shows that increasing the intake manifold's flow does not help too much even on a fairly modified SR20. Obviously the manifold is not a major choke point in the induction system. On an engine with race cams the gains would be larger as our manifold seemed to do the best at the very top end. Our computer simulation still indicates that a shorter runner manifold will help quite a bit. This is because the shorter runners will resonate at a higher rpm, improving cylinder filling through passive supercharging. This resonance tuning does not rely on pure steady state flow gains like extrude honing does. We are eagerly waiting for Kurt Sussman's short runner manifold, though we may have to wait until his baby graduates from high school!

Since the classic or pre-94 manifolds have longer, more curved runners, they have greater internal scrubbing losses due to the increased surface friction of the longer, deeper boundary layer (the still air near the runner's walls that does not contribute to flow). Perhaps this process would be more beneficial on one of these manifolds.

So in short, if you have an engine with just the easy bolt on parts, the Extrude Hone process most likely will not help much if at all. If your engine is really built with cams, headwork, compression, etc. and you are interested in getting every bit of power, you might consider it, but it would be a finishing touch type of modification.

If you have a killer high revving NA or high boosting turbo motor it might definitely be a plus.

Unorthodox Racing Underdrive Pulleys

Being skeptical of the claims for big horsepower on the Unorthodox Racing web site, we ordered up a set of their underdrive pulleys to do some extensive dyno testing. Joe at Unorthodox told us via a phone conversation that he felt that the pulleys would be good for about 5 hp on the SE-R.

When received, the pulleys were obviously CNC machined from billet aluminum and anodized a nice shade of blue. They were significantly lighter than the stock bits. We measured the TDC mark in relation to the keyway to make sure that the TDC mark was right on. It was. Unfortunately the TDC mark is the only one on the pulley so timing the car without a dial back timing light is impossible. Not a big deal for us as we have one of these timing lights but possibly a problem for the average joe. We suggest that Unorthodox add marks in 5-degree increments to the pulley instead of just a TDC mark.

To install the pulleys, we removed the passenger side wheel and wheelwell splash shield, exposing the front of the engine. An air impact was then used to remove the main pulley nut. The 10mm bolts holding the water pump pulley were removed with the belt still in place to prevent them from spinning. Two 6mm bolts were used in the existing holes to lever the stock main pulley off the crank. I don't really recommend doing this as it is real easy to punch a hole in the front cover this way. Use a puller or back up the bolts with a peice of thick metal to prevent damaging the cover. To get enough clearance to completely remove the main pulley, the passenger side motor mount had to be loosened and a jack placed under the motor to lift it slightly shifting the engine enough to get the pulley off. The new pulleys were installed in reverse order.

The stock belt for the water pump and AC compressor could be retained but a shorter belt was necessary for the alternator and power steering. We used a Bando p/n 6PK-1000 belt to replace the stock belt which was purchased from World Pack, a nearby parts house (1-800-733-2277). Bando makes genuine Nissan belts so I figured the quality of this replacement belt should be good.

After running the car, my SOTP estimate of power gain was small, about 1-2 hp. The engine felt more eager to rev and there was less drag when the AC compressor kicked on. I plugged in a CONSULT to test for charging function and overheating. The battery output stayed above 12 volts with all electrical accessories going full blast, including my aftermarket PIAA lights and 200-watt stereo cranking. When I made the electric windows go up and down at the same time the voltage dipped to 11.9 volts but I seriously don’t think that is a realistic estimate of potential power demand. I don’t think you would be caught in a very hot, very humid, foggy rain storm at night while broken down on the side of the road, engine at idle with every single light on, fogging up the windows while making out with your girl (or guy) stereo blaring and get a bug to roll the windows up and down to the beat of the music while waiting for the tow truck! If you do this frequently you may discharge your battery with the underdrive pulleys.

I tried to make the car overheat in bumper to bumper traffic on an 80-degree day, plus high speed cruising and free revving the motor to 7000 rpm for a few minutes. The coolant temp never went above 94 degrees C. I also did some violent slalom maneuvers to test the power steering. There was no sign of power steering pump up. The AC was perhaps a little less effective but it was hardly noticeable. After all this testing I conclude that the pulleys are at least safe. I think that under racing conditions the car may even run cooler as the stock water pump is prone to cavitate at over 6500 rpm.

Some list members have been concerned that the underdrive pulleys lack of an inertia ring as the one in the stock pulley could have some negative effects on motor life. I believe that this is not true. The SR20, unlike most domestic motors, has a fully counterweighted crankshaft and is internally balanced. It does not rely on a counterweight on the front pulley and flywheel to give dynamic balance like Ford or Chevy engines. Highly modified domestic motors are internally balanced at a great cost but us Nissan owners get that stock! I believe that the damper on the stock pulley is mostly to damp out accessory drive noise. With the underdrive pulley in place there actually seems to be less idle and high rpm vibration. I could not detect any increase in accessory drive noise but my car is sort of loud.

The next step was the acid test on DPR’s Dynojet chassis dynamometer. Amazingly the pulleys were good for a maximum of 6 hp over stock! The increase was about 2 hp at 2000 rpm rising in proportion with rpm to 5 hp at the power peak to 6 hp at the rev limit. The smooth gradual increase of power deceptively made the SOTP feel less. Normally most mods put a hump somewhere in the powerband that is easy to feel. Not so for the underdrive pulleys. Their seamless addition of power was very hard to feel. Being a skeptic we ran the car three more times to see if it was a fluke. All three runs yielded the same results.

At $189 list price these pulleys get our bang for the buck award! There are often group deals for less on the se-r mailing list.

Unorthodox has introduced a 4 piece pulley set that includes the power steering and alternator pulleys also. I have tested these and found perhaps a small 1 hp gain over the old 2 piece set. Shell Black has found a larger about 2-3 hp gain in his testing. Surprisingly I can feel a larger SOTP difference with the 4 piece set. Taking our suggestions, Unorthodox has improved the pulleys by adding a steel sleeve under the front main seal for longer life and is now adding all of the correct timing marks. The new product is even better.

We have also tested the pulleys extensively on the racetrack at temperatures over 100 degrees and found that the pulleys significantly reduce water pump cavitation induced overheating. Despite thrashing on a road course which is much harder on a motor than drag racing, we have yet to see any increase in wear on the motor.

Big Bore Throttle Bodies and MAFs

I recently tested the RC engineering big bore throttle body. This throttle body is 64mm vs the stock 60mm. The workmanship and attention to detail are superb. The throttle body casting is honed to tight tolerances so a good idle can be maintained and the throttle shaft is aerodynamically profiled with streamlined button head bolts that are staked, much like OEM. Although it felt like it was giving a lot more power in my SOTP evaluation, on the Dyno no power increase at all was registered just as I had previously predicted. My theory is that it improved throttle response so much that the engine seemed a lot more powerful. However, I think this mod is worth while just because of the vast improvement in feel and response. Perhaps with more mods, the engine will need the additional flow and the TB will actually help.

I also tested using a big 80mm MAF from a late model Maxima using a custom programmed JWT ECU. My engine is getting close to the point where it can top out the stock ECU but not quite yet. Even through the Maxima unit is nearly 45mm larger than the tiny stock MAF, I did not gain any power except for about 2-3 below 4000 rpm! My theory on this is that the larger hole helped the CAI resonate better at lower rpm. I don't think bigger or bored out MAF's like Stillen sells are worth it unless you are turboed or your engines are modified to the point where they can pull more than 5.15 volts on the airflow meter. This is the point where the stock MAF is maxed out.


Spark plugs and Ignition systems

There is a lot of controversy on the list on what is the best, most appropriate sparkplug for our cars. My opinion is yet another one but at least it is backed by years of racing experience and recent dyno testing.

Heat Range of plugs
Sparkplugs come in many heat ranges. This is so the plug can be matched to the type of use an engine receives. For low speed, short hop driving, the plugs electrodes must stay hot enough to burn away and self-clean fouling carbon deposits. For this type of driving a hot plug is needed. For high speed racing at high rpm, the plug can become too hot and glow like a diesel glowplug causing pre-ignition and detonation. This can quickly destroy an engine. To prevent this a cold heat range plug is needed.

The length of the insulator of the center electrode determines a plugs heat range. You can tell a cold plug from a hot plug by looking at the center electrode’s insulator. If the porcelain insulator is short, it is a cold plug. If it is long and extends deeply into the steel shell of the plug, it is a hot plug. This is because a cold plugs short center electrode has a short path to conduct heat out of the electrode. A hotter plug has a longer path and dissipates heat more slowly.

Most listmembers seem like they are unaware of matching the spark plugs heat range to the type of driving that they do. I wince when I think that many are squeezing nos or pumping turbo boost with the stock hot plugs.

In my opinion the best spark plugs for the SR20DE and DET are the stock Genuine Nissan NGK platinum plugs. I like a decent platinum plug. Platinum is a noble metal with a high melting point. Being almost inert, it is highly corrosion resistant even at high temperatures. That is why a platinum plug lasts about 3 times longer than a conventional plug. When used in the plug's electrode it resists erosion much better than steel.

Stock Nissan plugs have platinum in both the center and ground electrode for really long life. Most aftermarket platinum plugs only use platinum in the center electrode. I prefer for most engines, even the stock ones, to run the PFR6B-11 spark plug. This is the middle heat range for the NGK plugs. SR20 powered cars come with PFR5B-11 plugs, which are one heat range warmer. Originally when the SR20 was first introduced, the cars came with PFR6B-11s but they were fouling out during port storage where the cars are continuously being started, moved a few feet, and shut off. The countermeasure to high warranty on low mile sparkplugs was the switch to the hot plug.

The PFR6B-11 works well on high compression, turbocharged or NOS powered cars. For running extreme boost (more than 18 psi), a big shot of nos (more than 100 hp) or really high compression (more than 11:1) the cold PFR7B-11 plug is necessary. This plug will be on the edge of fouling during regular day to day driving so it can be considered a race only plug.

The SR20 has a shallow included angle of the combustion chamber. This makes for a quick burning, detonation-resistant chamber. I have also found that shallow included angle chambers for the most part do not like extended tip plugs. When experimenting with extended tip plugs I have found that the engine loses about 3-4 hp across the board. Many aftermarket plugs are extended tip. The theory behind extended tip plugs is that the extended tip puts the electrodes in a more turbulent section of the combustion chamber, thus helping them stay clean of fouling.

In the SR20 an extended tip plug puts the electrode too close to the piston dome screwing up flame propagation, thus losing power. This is important to consider if your are deviating from the Stock Nissan recommendation. Make sure that the tip of the plug that you are buying does not extend further than the stock plug’s tip. If you are running flat top or domed pistons, this is even more critical as the tip of the plug is even closer to the piston dome.

The SR20 has a powerful stock ignition that can fire through turbo boost and NOS. Gap the plugs at 0.045". If you experience misfire under squeeze or high boost (and the rest of the ignition system is in good condition, like the cap, rotor and wires) you can close the gap down to as small as 0.020" to prevent it. Go down in 0.005" increments until the misfire stops. Higher cylinder pressures cause by big NOS or high boost requires smaller gaps with the stock ignition. The smaller gap loses a little power but this trick can tide you over until you can get that snazzy turkey roaster ignition.


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High Power Ignition
I haven’t run across a SE-R that has needed this yet but I suppose that over a 100 shot of nos or 18 psi of boost might need a high power ignition. Jacobs ignitions are crap. I would not bother with them. I prefer an MSD 6A or better unit. I have never needed an MSD on an SR20 yet but I have had very good luck with them on other cars including racecars. The Crane Hi 6 has gotten rave reviews also but they seem prone to burning out (two of my friends have been stranded because of a burnt out Hi-6). These ignitions are very powerful, capable of firing the spark plugs for over 30 degrees of crank rotation. Just the thing for high cylinder pressures.

I have a Nology coil booster on my SE-R. It seemed kind of hokey but I installed it. It has allowed my car to run smoothly even with the plug's electrodes completely burned off. When the coil booster was unplugged the car would barely run so I guess it works well. The Nology coil booster is the only easy way to hop up a 200SX’s ignition as the coil is an integral part of the distributor.

I believe I have found the limits of the stock SR20 ignition system. On Ryan's turbo car, when exceeding 10 psi of boost we developed a misfire which required that the plug gap be closed to 0.020". Even this was only good to 14 psi before misfire started again.

On my 11:1 compression NA motor misfire was happening until I closed the gap also.

So on really built cars I now recommend the MSD 6A or SCI ignition system. On 95 and later cars with an internal coil, MSD makes an external coil conversion kit for Hondas that also works on our cars. Just be sure to cut the primary conductor from the stock coil and fill the resulting hole in the distributor cap up with silicone or some of the extra power from your new coil will be wasted.

As a note, these ignition systems don't seem to work too well with Nology wires. I use either stock or NGK wires.

These high power ignitions will not give you much more power but they will eliminate frustrating misfire and help starting and low speed driveabilty.


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OTHER PLUGS

Bosch Platinum
I hate these plugs. They have a weird center electrode that is flush with the insulating porcelain. What happens is that this electrode quickly erodes so it ends up being a depression in the porcelain, making the spark shoot out of a hole. Sparks like to propagate from sharp edges so I think they have a hard time getting out of this hole.

These plugs will absolutely not work for long in high compression, high rpm, boosted or NOS applications. The are marginal on a stock engine. In my experience they work OK for a few thousand miles then start to idle roughly and on modified engines misfire under load. It amazes me that an OEM level supplier like Bosch can make pieces of crap like these.

Some listmembers have recently dyno tested these plugs on stockish engines and have found them to be OK. This included some used plugs that were at least 20k miles old. My personal opinion is that these are pretty bad for most stock motors. The VG30 in my Pathfinder will barely run with these plugs. Kit Wetzler also experienced poor driveabilty in his NX2000 with these plugs.

[ Ed note: This is Mike's opinion of these plugs based on his personal experience. Go to Bosch Platinum vs. NGK Platinum Spark Plugs for a comparison of the two. -MM ]

Bosch Plus 4
Although I have not had any experience with them, Chris Pinthong and Dave Coleman have tested them and found them to work well. These plugs have an unusual design with 4 ground electrodes much like a rotary engine plug. Hopefully they are much better than the regular Bosch Platinum.

Beru
These plugs have a silver conductor for the center electrode. Since silver conducts electricity better than steel or copper it is reportedly better. The electrode material is still steel so I don’t think that these are much of an advantage.

NGK V plugs
These work fine, just change them frequently. Be sure that the tip does not extend further than the stock plugs.

Split Fire
I call these Miss Fires. They have an extended tip that the SR20 hates. The dual ground electrodes may have some merit by creating more sharp edges for spark propagation but this is moot when the extended tip causes hp loss.

Champion, AC and others.
I don’t have any experience with these. Make sure the heat range and tip length is appropriate for our motors. I think that these brands have some premium labels that have unique electrode configurations to have more sharp edges for spark propagation. Some list members have had good luck with these.

The main thing to remember with SR20s is that the plug’s tip length must be close to the stock plugs or power loss will result and the heat range must be appropriate for the intended end use or engine-destroying detonation may occur.

Reader's Contributions

Here are some suggestions from one of the original 14 second club members, Pat Griffith. These are how some common bolt on parts have affected 1/4 mile times on his car

Pat writes:

JWT ECU -- lowered 1/4-mile time by .26 seconds; increased trap speed by almost 1.93 mph. Runs were about a month apart at the same track.
Header -- lowered 1/4-mile time by .39 seconds; increased trap speed by 2.08 mph. Runs were a year apart, but at the same track with the same temps (about 40 degrees).
HKS exhaust -- I can't compare it to stock (out of 60K miles I've put on SE-Rs, only about 400 have been bone stock , but I can compare it to the Stillen muffler. The HKS (cat-back, of course) lowered 1/4-mile time by a tenth; increased trap speed by .79 mph. Again, both runs were at the same track. Not sure of the temps, but they were probably similar (April vs. Sept.), if not, a bit *warmer* on the run with the HKS. Very noticeable top-end improvement.

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Justin Choi Writes:

I had a custom cold air intake made for my 92 Nissan SE-R a while ago and got my hands on a Techtom to test it out. The Techtom allowed me to measure the voltage at the Mass Air Flow sensor. Voltage readings at the MAF (Mass Air Flow) Sensor are used by the ECU to find out how much air is coming through the intake. The ECU then adjusts the fuel accordingly. Honda's don't have a MAF but use a different reading to do the same thing. I believe it's the manifold pressure. The more air I get, the higher the voltage reading I should receive on the MAF.

TESTING:

The cars that we used for testing were a 92 SE-R with headers and 2 inch exhaust and a 94 SE-R with headers and 2 inch exhaust. Although the testing was done on Nissan cars, the same principals apply to Hondas. Instead of testing the cold air system against a stock intake, we gave it a real test by testing it against the proven Jim Wolf Technology POP Charger system. The POP charger utilizes a large K&N cone filter with a 7 inch base and nice billet velocity stack.

The Techtom allows testing of the car out on the road in real-world conditions. There are some issues regarding Dyno-testing of cold air systems since the car is stationary. This makes underhood temps higher than normal and may skew the results in favor of the cold air systems.

RESULTS:

Stationary (no-load, zero MPH) Outside Temp ~ 75 degrees

94 SE-R with JWT POP Charger: 4.34
92 SE-R with Akimoto Funnel Ram II filter with dryer hose bringing in outside air: 4.28
Red Line up to Third Gear (Approx. 95-98 MPH) Outside Temp ~ 75 degrees

94 SE-R with JWT POP Charger: 4.34
92 SE-R with Akimoto Funnel Ram II filter with dryer hose bringing in outside air: 4.28
Stationary (no-load, zero MPH) Outside Temp ~ 87 degrees

94 SE-R with JWT POP Charger: 4.34
92 SE-R with Akimoto Funnel Ram II filter connected to the cold air intake pipe: 4.34
Red Line up to Second Gear (Approx. 65MPH) Outside Temp ~ 87 degrees

92 SE-R with Akimoto Funnel Ram II filter connected to the cold air intake pipe: 4.45
92 SE-R with new K&N filter connected to the cold air intake pipe: 4.47
Needless to say, a huge difference!

The Project 200SX SE-R in Sport Compact got the same intake done at the same place (Place Racing in Covina) and he dynoed it at an 8 horsepower increase. Mike Kojima, the writer and owner of the 200SX SE-R concluded that it was the best bang-for-the-buck item available. He got an average of 5-6 horsepower at every RPM above 3000 over his old JWT Intake with no loss of HP under 3000.

DISADVANTAGES:

Having the filter in the bumper area can make installing cold air setups a pain in comparison to a standard air intake system. Also, if you hit a flooded street you'll end up ruining your motor. I do know of one case where that did happen and it was in "sunny" Southern California during our one week rainy season. However, most of those with cold air intakes drive in the rain and hit puddles with no problems at all and many setups can be changed to allow the filter to sit in the engine bay. Also, a cold air system involves more piping and this means that your intake will be very loud under heavy throttle, louder than it would be with a standard intake. It's a nice deep growl so to most, it's an advantage, not a disadvantage. [Editoral note: So far with this year's rain in CA, we haven't heard of any problems from hydro lock. Several people hit some large puddles but didn't have any problems.]

CONCLUSIONS:

The recent Sport Compact Car article on intakes tries to leave the impression that their tests aren't 100% conclusive. Well, they have advertisers to worry about and aren't willing to make a definitive recommendation. From my personal experience on many different Hondas and Nissans, I can tell you without a doubt that the cold air setups offer more horsepower than standard K&N and intake stack setups on most cars. I have also seen many cases where horsepower was lost after the addition of a standard underhood air intake system. I've tried various home-made setups that bring in cold air through plastic pipes or dryer hoses and none of these have tested to show any improvement whatsoever. A major portion of the gain is from extended the pipe length of your intake and those home-made setups don't provide that. Get some setup, either from the aftermarket or whatever home-made concoction you can come up with, to extend your intake pipe and get your filter away from the heat of the engine but not too close to the ground and you should be in good shape.


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Justin Choi Writes:

As far as the other filters are concerned:

I've tried the:

Akimoto Funnel Ram II with velocity stack
Weapon R foam filter
Weapon R foam filter with velocity stack
Baby K&N
Medium K&N
Large K&N
JWT Pop Charger
I only have SOTP [Editor: that's Seat Of The Pants] impressions for most of them. Obviously, I like the JWT setup the best. I wish I had something objective to contribute to the list other than the fact that I don't think it's worth the time or the effort to try the foam filter. It didn't make any SOTP difference and I did a lot of research and found that:

Banzai claims that foam doesn't flow as good as a gauze filter but they flow better than K&N when dirty.

HKS claims that their filter just flows better.

K&N claims that the gauze flows better and especially flows better when dirty.

I've heard stories of people getting little bits of foam in the engine with the foam filters (Dynamic Autosports). John at Hotshot told me of a story where the plastic funnel of the Akimoto Funnel Ram broke off during full throttle operation and jammed itself in the throttle body causing a major accident. JG had an Integra that wasn't producing as much on the Dyno as it should have. They removed the K&N filter and the dyno showed a 5-7 horsepower increase. Then, they added the Unifilter (foam) and got another 2 horsepower! So they say! This was on an Integra with headwork, cams, and all the bolt-ons. John at Hotshot swears by the foam filters. The foam filters are hard as hell to oil since they don't seem to absorb the filter oil very well. (John at Hotshot did tell me to oil it).

The bottom line is that the K&N is considered numero uno by majority of the people out there. Why not go with #1?

It would be cool if the originator of this thread updated it to todays products and standards.