VITARA INFO Thread-Add Your Knowledge
I thought it would be a great Idea to start a thread with all the Vitara Piston Info along with custom rod lengths vs standard length info so that you don't have to see 100 threads a week asking the same question. So if you have valuable Information to add go ahead and maybe we can get this stickied. I know all the info is out there it just needs to be put in 1 thread.
A 75mm Vitara Piston has a compression height of 28.3 and a dish volume of -15cc
The standard Length rod for a D16 is 137mm
The Custom Length FJ Rods for a D16 are 138.63mm(5.458 in)
(This puts the piston closer to the deck surface increasing compression ratio.)
All numbers were calculated using the Zeal calculator. Honda D-Series Compression Calculator by ZealAutowerks
The Head gasket used for calculations was a Y8 2 layer (.025)
Approximate compression ratios with 75mm pistons (Compression increases roughly.07-.08 with 75.5mm pistons)
D16z6 with standard length Rods and Vitaras- 7.64 to 1
D16z6 with FJ custom length rods and vitaras- 8.54 to 1
D16y8 with standard length Rods and Vitaras- 7.84 to 1
D16y8 with FJ custom length rods and vitaras- 8.81 to 1
D16a6 with standard length Rods and Vitaras - 7.28 to 1
D16a6 with FJ custom length rods and vitaras- 8.09 to 1
With a z6 gasket( .037 ) compression numbers go down ~.15
With a A6 gasket( .048 )compression numbers go down ~.25-.28
Compared to the 2 layer Y8
So obviously if you are looking for the highest compression gasket you would go with the 2 layer Y8 gasket
The highest compression ratio can be made using a y8 head due to the difference in combustion chamber volume.
D16y8 head = 32.8 cc
D16z6 head = 34.6 cc
D16a6 head = 38.0 cc
THE GREAT ARROW DEBATE-
"Arrow towards the flywheel on a D-series is the current thinking. The reason being the pin is slightly offset and the Honda engine turns backwards, hence the reversed orientation." This Is True yet many have been ran the other way as well. JFK has his arrows pointed towards the flywheel and has made 600+hp. Others have made 400 with the arrow towards the timing belt.The main thing to remember is that you will get pistons slap both ways if you have a very large PTW clearance.
Actual Piston Sizes- These measurements have been taken by various members of the D-series community.
Ycp 75.5mm vitara's from FJ Distributors
Piston 1. 2.9684"
Piston 2. 2.9684"
Piston 3. 2.9683"
Piston 4. 2.9682"
Piston pin diameter - all 4. .7470"
Piston pin offset
Intake - 1.1195"
Exhaust - 1.1380"
Intake relief width - 1.0490"
Intake relief depth - 0.1530"
Exhaust relief width - 0.9615"
Exhaust relief depth - 0.1685"
Measurements were taken with arrow towards flywheel.
PTW Clearances with Vitaras-
Many have heard .001 for every 100 hp so that is what I will stick with. This is a good rule of thumb and has worked in many builds. Normal Vitara builds are shooting for roughly 250-400HP so .0025" to .004"
Notching- There have been many different opinions on notching with the Different types of Rods. For Eagles it has been pretty much standard to notch the block and Girdle,I have heard of some people getting away without though. For the FJ Rods the same has been said. Fj States that no notching is required for the D15B though due to the shorter stroke.But it is needed with the d16s . My opinion is @ 8000 Rpm I want to make sure shit clears. So a standard notch job may be or may not be "needed" but It will definitely give you a peace of mind if you are close during assembly.
The Old One - Energy Dynamics : Articles
-Great article on notching
- for all your vitara/custom length rods
- Some High HP Vitara Builds
THE NEW COATED VITARA PISTON- Measures 2.953
Please add info to this thread as you read it.:bigok:
Previous Vitara Piston Question threads: