Contact Engine Calculator
A dynamic compression ratio that looks off, an octane recommendation that disagrees with your tuner, an engine preset that doesn't match your casting number, a feature you wish existed — this page routes your message to the person who can re-run the check and verify your geometry, not a form that vanishes into a queue.
Most replies within two business days — correction reports that affect calculator output are prioritized.
Answered Already, Most Likely
Most compression ratio questions are covered somewhere on the site. These are the destinations that resolve the majority of emails — worth a look before you write. The fastest path to a fixed DCR check is usually one of these pages.
Every email read by a humanPhoto: Unsplash- How to Use the Calculator Step by Step
- What Compression Ratio Actually Measures
- The Formulas Behind Every Result
- Slider-Crank Piston Geometry Explained
- Octane & Forced Induction Guidance
- Engine Preset Quick Reference
- Calculator FAQ on the Home Page
- The Compression Ratio Guide Library
What to Include for a Fast Reply
- ✓Browser & device (for UI glitches)
- ✓Bore diameter, stroke length, and cylinder count
- ✓Chamber cc (burette-measured or from factory spec)
- ✓Gasket thickness and bore diameter
- ✓Piston dome/dish volume and deck clearance
- ✓Rod length and intake valve closing angle (for DCR)
- ✓Altitude, fuel type, and boost level (for octane guidance)
- ✓The result you expected vs. the result shown
A screenshot of your calculator inputs halves the back-and-forth.
Pick the Right Inbox
Four routes, four inboxes — each one lands with someone who can act on it. Unsure which fits? Use support@ and we will forward it ourselves.
Engine Support
Calculation & Results Help
A static CR or dynamic CR that doesn't match your math? Send the inputs you entered — bore, stroke, chamber cc, gasket thickness, piston dome/dish volume, deck clearance, and IVC angle with rod length — along with the result you expected versus the one shown.
Corrections
Report a Formula or Preset Error
The engine computes swept volume via (π/4)·bore²·stroke, total clearance volume from chamber + gasket + piston + deck, dynamic CR from slider-crank geometry, and octane ranges per engine-building references. If any output, engine preset bore/stroke, or DCR calculation disagrees with a factory service manual or respected reference, send the page URL and exact numbers.
Product Feedback
Feature Requests & Ideas
Want more engine presets, metric-only display (mm/cc vs inch), saved engine builds, a printable build sheet, or forced boost correction for combined CR × boost? We build from what engine builders, machinists, and cam grinders actually need at the workbench — including real stories from the machine shop.
Partners
Partnerships & Education
Piston manufacturers, gasket makers, cam companies, performance parts distributors, race schools, and automotive education programs — we are open to classroom integrations, co-developed calculators, printed engine-building companions, and motorsport event materials.
What Happens After You Hit Send
No ticket numbers, no canned macros. Here is the actual path a message takes from your outbox to a verified answer — the same path whether you found a half-point DCR discrepancy or want a new engine preset added.
| Step | What Happens | What It Means for You |
|---|---|---|
| 1 | A Person Reads It | No ticket bot, no autoresponder loop. Messages with exact inputs — bore, stroke, chamber cc, IVC angle — are reproducible, and reproducible messages get answered first. |
| 2 | We Re-Run the Compression Check | For anything numeric, we rebuild your engine calculation by hand — geometry, swept volume, clearance components, slider-crank DCR, and octane range — and compare against the factory service manual and industry references before replying. |
| 3 | You Get the Math Attached | The reply shows the formulas and the inputs that moved the number. If we were wrong, the reply says so plainly and the fix is dated on the page it affects. |
| 4 | The Receipt Is Kept — Ours, Not Yours | Verified corrections and strong feature requests feed the roadmap. Your email stays with your thread, is never added to a list, and there are no lists to add it to. |
Quick Answers
The five questions we hear most from engine builders, machinists, and tuners.
How do I get a faster reply?▼
Include the exact inputs: your bore diameter and stroke length, cylinder count, chamber cc (burette-measured or known), gasket thickness and bore diameter, piston dome or dish volume, deck clearance, rod length, intake valve closing angle (ABD or @ 0.050" lift), and altitude if relevant. Add the result you expected versus the one shown. That one message usually lets us reproduce and explain the difference in a single reply.
Do you offer live chat or phone support?▼
Not yet. Email lets us re-run the full compression calculation and verify every answer against the exact geometry and industry references before responding — which matters when the topic is a $2,000 piston set or a head-milling spec. We read every message and answer most within two business days.
Can you tell me exactly what octane grade I need?▼
We can tell you what the calculator's method says for the dynamic compression ratio you enter — and show every formula behind it. But DCR targets are guidelines, not laws: quench area, valve shrouding, combustion chamber turbulence, and ignition timing also determine detonation resistance. Your tuner or engine builder makes the final call.
Do you sell pistons, gaskets, or heads?▼
No. The site sells nothing, carries no affiliate links to Summit, Jegs, or any manufacturer, and is not affiliated with any parts brand. Advertising is clearly labeled and separately handled — see the advertising section of the Privacy Policy for how that works.
Can I suggest a topic for the guide library?▼
Please do — that is how the library grows. Send the question you were trying to answer, the engine you were working on, and what you wished had been written down. Requests that describe a real machine-shop or track problem (e.g., 'how does rod ratio change dynamic compression?') go to the top of the content queue.
Still need a human? One tap away.
One inbox per purpose keeps your message from bouncing between desks.
Everything Links Back to the Tool
Every answer we send names the exact calculator input that changes — bore, chamber cc, gasket thickness, IVC angle — so the fix is something you can apply yourself in seconds.