Tech Info

Tuning Information and Tips

The following items are some items that I have developed over the past few years that help with tuning, engine building, and turbo’s. Some are engine specific while others are universal. Any fuel/timing maps are on here so that you can get a good starting point. These are base maps only do not attempt to drive your car hard on these without tuning. All files are Microsoft Excel or Word.

Compressor Math
This little guy is compliments of myself and Jay Waller (Black Bomber). A very useful tool for calculating compressor flow on any engine vs. RPM. It is pretty self explanatory (Thanks Jay!)

Compression Worksheet

KA Stock Timing Map
Straight off the S13 KA24DE ECU. The stock timing map for those trying to work with E-Manage and a Consult to hack out a tune. You should really upgrade to one of my ECU’s…but if you must.

KA Stock Timing Map

SR Engine Bearing Calculator
Developed this one while building a motor last year. I wanted a neat little spreadsheet to track my sizes and measurements. It works like this: -Measure your crank diameters (main and pin journals)
-Enter crank measurements into spreadsheet
-Measure main bore and rod big end diameters
-Enter diameters into spreadsheet
-Decide what bearing clearance you want to run
-Enter clearance into spreadsheet.

Now the spreadsheet will calculate the thickness of bearing (each half) you need to achieve your desired clearance. Then just change the number to correspond with the grades listed to the right.
These are RWD bearing sizes and thickness. They are the same as FWD Sentra SE-R. GTi-R bearings are a different thickness. The grade specs on this spreadsheet do not apply to GTi-R.

SR Bearing Calculator

SR Camshaft Alignment Procedure
One of the most common problems I have to troubleshoot for customers is improper camshaft install. It is an easily confused process because Nissan engineers did a poor job at marking TDC on the cam sprockets. So you have to approach it with a more precise method than 10 and 12 o’clock. Tomei cams come with a nice little guide on how to make sure your cams are in time. It is just a picture with some kanji and markings that helped me a lot. So I put it into English text instructions.

SR Cam Alignment Procedure

SR Compression Ratio Calculator
Want to determine the compression ratio of any engine build? This little guy can help. The spreadsheet is setup fro a stock RWD SR20DET. It works like this:

Enter Bore (mm)
Enter Stroke (mm)
Displacement per cylinder is calculated

Enter number of cylinders
Displacement of engine is calculated

Enter head gasket bore (mm) (as a rule this should be 0.00 to 0.50mm greater than the bore)
NOTE – RWD/FWD SR20DET is 1.1mm thick stock. FWD SR20DE (NA) are 0.9mm
Enter head gasket compressed thickness (advertised thickness on multi layer metal gaskets)
Gasket volume is determined

Enter deck clearance (mm) (positive for edge of piston below deck surface)
Deck clearance volume determined

Enter piston volume cc’s (negative for dish pistons, positive for domed)

Enter head cc’s – SR20DET/DE heads are 45-46.5cc depending on a few variables.
NOTE – The head cc’s listed on the Wiseco piston web site are wrong. I have never in my life seen a 60cc SR20DET head – redtop, blacktop, s13, s14, s15, GTi-R, bluebird, even NA sr20de they are all 45-46.5cc. As a result Wiseco has incorrect compression ratio info on their web site for their pistons. I would like to see a 60cc SR head that has not had headwork if anyone can produce one.

Compression ratio is calculated

SR C.R. Calculator

SR Power FC Base Maps
For you Power FC guys. You should have one of my tunes instead…but here is where I start from when I tune a Power FC. You will have to change almost every value of the 800 total between fuel and timing. Using the commander will result in extreme gameboy thumb pain syndrome.


SR PFC Base Maps

SR Standalone Timing

So you are trying to tune your own standalone. This timing map should give you a good place to start from. Recently updated due to confusion over the units I used for pressure. It is now written in kPa – Absolute Pressure


SR Standalone Timing

Turbo Calculator
This one is not completely my work. The majority of this spreadsheet is the work of a John Estill a Grand National enthusiast and one hell of a smart man! You can contact him directly
I got it from some local GN guys a long time ago and sat on it for a while until I better understood turbos. At that point I took to modifying it for modern high V.E. import engines. This is the most advanced guide in this section. If you need help with it please contact me on AIM or e-mail. This spreadsheet can calculate pretty much any thing you need for turbos and fuel injection.
John and I are currently discussing some other changes to the spreadsheet so stay tuned!
Lots of thanks to John Estill for getting this thing going!

Turbo Calculator