Ask Sarah: MotoIQ "linked in"

By Sarah Forst


Why reinvent the wheel?  All the answers below also have links for more detail. It's MotoIQ extra credit!

I have a 1996 200SX and would like to upgrade the ignition with an MSD 6A box and external coil. Do I have to modify the stock ignition cap or is an aftermarket unit available?


The stock Nissan ignition is good enough for most setups.  If you're not boosting, squeezing, or exceeding the rpm limits the stock ignition can handle- typically around 8000rpm for the SR20DE- you shouldn't need to upgrade to an aftermarket ignition.  The stock SR20DE ignition can handle up to 16-18psi of boost or a 100 shot of nitrous oxide.  But once you get to that level of modification, the denser intake charge increases cylinder pressures and the stock ignition isn't capable of the ionization needed to produce a good enough spark to ignite the mixture.  This is when you'll need a high powered ignition system to prevent misfire.  
MSD ignition with external coil
Just make sure you're setting up your ignition for your power goals.  Sometimes the aftermarket ignition is too much for normal driving conditions.  I have a Digital 7 Plus with MSD external coil on my SR20.  I also set up the MSD tach adapter so my tach won't go beserk trying to handle the MSD's multiple sparks.  This ignition setup (and my spark plugs gapped at 0.021") was essential when I dyno'd at 473 whp at 26psi, but kinda sucks for just driving around at low boost.  
The MSD 6A or Digital 6 is good for boosting around 20psi while the 7AL or Digital 7 can help with higher boost pressures.  On the 1995+ SR20DE engines which have an internal coil, MSD makes an external coil conversion for Hondas that will work with some modification.  You'll need to cut the primary conductor from the stock coil, solder in a wire that exits out the distributor, and fill in the hole in the distributor cap with silicone.  This wire will be used to trigger an external ignition system.  Jim Wolf Technology offers an awesome how to (with pictures!) on their website for modifying the SR20 distributor with internal coil.
Hi Sarah, 
I have attempted to find the answer to this question to no avail. Please can you help?  I have purchased a GL1 cable from GoPoint Technology for my iPhone. I am about to download DashCommand through iTunes, but I would like to know if the readings: fuel, etc can be switched to metric?  Eg L/100Km. Liters, Kilometers etc.  I have looked through your Web Site and could not find the answer.  I would be pleased if you can answer this for me.
Regards, Murray Kirkness
Dash Command dashboard
Dash Command dashboards are available on DashXL.net and can be customized to your preferences or you can create your own interactive dashboard for the settings you wish to monitor.
Dash Command offers both English and Metric unit settings.  Both units are visible in the Data View, but the dashboard settings must be changed to show metric units.  For the iPhone version, go into Settings, scroll to the Setup group and click on Units, then select English or Metric.  It appears there is currently an issue with the application reverting back to English settings if you try to go "back" immediately after changing this setting.  You may be able to get around this by selecting another screen within the settings menu and then going back.  I did confirm with their support team that they are currently working on a fix and hope to have an update available soon.  They actually have a pretty good forum that includes guides, troubleshooting, and more.  I suggest you keep checking there for when that fix is available.   
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Tuesday, April 24, 2012 3:34 AM
I take it, if a car had a radiator that is higher than the heater hoses in the engine, a swirl pot would be unnecessary? Say in a buggy or SAE car?
R. Motoki
R. Motokilink
Tuesday, April 24, 2012 4:29 AM
When using a swirl pot/surge tank I'm assuming the cap on the radiator must open at a lower pressure than the one on the surge tank, correct? Or is it bypassed entirely?
Mike Kojima
Mike Kojimalink
Tuesday, April 24, 2012 7:01 AM
A swirl pot is a good idea in any race car. The radiator cap is bypassed.
OMG Its Weasel
OMG Its Weasellink
Tuesday, April 24, 2012 11:44 AM
There is a really great pair of images halfway down this page that helped me to understand how coolant swirl pots/tanks work: http://www.gtfactory.jp/cms/page.php?11
Not that your image isn't good, Sarah, but JDM images are way more awesome.
Tuesday, April 24, 2012 1:35 PM
That is not a swirl pot (in the article and in the link above)! That is a header tank. The swirl pot has two BIG flanges on it and goes inline in the MAIN return hose from the engine. The swirl pot has a small port on top and is connected to the header tank (the pictured ones above) to route out the extracted air.

The swirl pot in the main return hose swirls the water, bubbles get extracted on top and get sucked via the top port towards the header tank.
Those header tanks in the picture above don't do any swirling whatsoever.

Here is a picture of what a swirl pot for a race car looks like:


You can see those on many airplane engines too.
Tuesday, April 24, 2012 1:52 PM
Since coolant swirl pots are mentioned often at MotoIQ, but I have yet to see an article showing the swirl pot itself - all I see is picture of half of the system (the header tank) ...

Sorry for the small picture, but here is a diagram of how to route a swirl pot and connect it to a header tank:


The header tank must sit at the highest point in the engine bay. It collects the air and eventually pushes the collected air out to the overflow tank (via the radiator cap) when the coolant starts expanding. The header tank is plumbed in the inner coolant loop and has a line at the bottom to the water pump.

The swirl pot is plumbed inline in the main coolant line (the big line from the engine to the top of the radiator). It has a single small port on top and is connected to one of the top ports of the header tank. Swirl tank can be mounted down low in the engine bay - just make sure it is oriented/plumbed properly: the small port should be on top. the inlet port (the line from the engine should be the higher one of the two big ones)

Mike Kojima
Mike Kojimalink
Friday, April 27, 2012 12:33 PM
How are you JC? You havent been around much.
Sunday, April 29, 2012 7:03 PM
Sarah, was it the MSD 8910 tach adapter for the sr20?
Sarah Forst
Sarah Forstlink
Monday, April 30, 2012 12:12 PM
@ny: Yep, that's the one.

@OMG: Thanks, I'd JDM it myself if we didn't have copyright infringement to worry about ;).
Tuesday, August 07, 2012 10:31 PM
The early SR20's also have another option if you dont mind doing the wiring and sourcing the 20V or VET valve cover... coil on plugs!

I should have mine completed soon.
Thursday, August 16, 2012 12:18 PM
Got it working!
Got my plugs gapped at .033, they were at .025.
Ive been told I can go up to .038 on 20psi.
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