Automotive Calculators
Engine displacement in cc, litres and cubic inches from bore, stroke and cylinders; compression ratio and mean piston speed.
OtherLiveeip155:8453Exactvia cdp
AutomotiveEngineDisplacementCompression-ratioCalculator
Calls · 30d
1
This endpoint's own trailing-30-day call count, as published by the upstream catalog and snapshotted daily. 4 snapshots so far.
$24.31
Verified settled volume
1,175 settlements proven x402 by their on-chain EIP-3009 marker.
$0.020
Listed price
As published in the catalog. Always read the live 402 before paying.
1
Calls · 30d
Upstream's own call count for this endpoint, not ours.
1
Unique payers · 30d
Last called 2026-10-20 20:45Z
—
Upstream on-chain volume
Reported by the source catalog.
Paid to
0xb531320805C5BED1D46AEaDcF4F008FDF172DBDaThe wallet the 402 directs payment to. Its whole payment record — every payer, every chain — is on the merchant page.
Asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913
Provider
The payTo wallet does not resolve to a registered ERC-8004 agent. That is not a verdict on the service — most of the catalog is unregistered.
Live 402 challenge
Captured by the enrichment pass, not read just now. Prices can change — always read the 402 the endpoint answers with.
{
"error": "Payment required",
"accepts": [
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"extra": {
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"version": "2"
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"payTo": "0xb531320805C5BED1D46AEaDcF4F008FDF172DBDa",
"scheme": "exact",
"network": "base",
"mimeType": "application/json",
"resource": "https://automotive-calc.x402tookit.com/engine-calc",
"description": "Engine displacement in cc, litres and cubic inches from bore, stroke and cylinders; compression ratio and mean piston speed.",
"outputSchema": {
"input": {
"type": "http",
"method": "GET",
"queryParams": {
"rpm": 6000,
"bore": 86,
"unit": "mm",
"stroke": 86,
"cylinders": 4,
"clearanceVolumeCc": 49.9
}
},
"output": {
"asOf": "2026-10-11T14:38:36.873Z",
"boreMm": 86,
"design": "square",
"source": "computed locally",
"reasons": [
"Displacement = pi / 4 x bore^2 x stroke x cylinders. Compression ratio = (swept volume + clearance volume) / clearance volume. Mean piston speed = 2 x stroke x RPM / 60.",
"1 cubic inch = 16.387064 cc."
],
"summary": "4 cylinders of 86 x 86 mm displace 1998 cc (2 L, 122 cubic inches); square. Compression ratio 11.01:1. Mean piston speed at 6000 RPM is 17.2 m/s.",
"verdict": "COMPUTED",
"degraded": false,
"strokeMm": 86,
"cylinders": 4,
"disclaimer": "Screening signal computed from the named public source. Not financial, legal or investment advice; provided as is. Verify at the source before acting.",
"notChecked": [
"the actual compression the engine makes: the static ratio ignores valve timing, boost and head-gasket thickness unless you include them in the chamber volume",
"knock limits and fuel octane for a given ratio",
"…2 more"
],
"displacementCc": 1998.23,
"boreStrokeRatio": 1,
"compressionRatio": 11.01,
"meanPistonSpeedMs": 17.2,
"displacementLitres": 1.998,
"compressionRatioText": "11.01:1",
"meanPistonSpeedFtMin": 3386,
"displacementCubicInches": 121.94,
"displacementPerCylinderCc": 499.557
}
},
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"scheme": "exact",
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"resource": "https://automotive-calc.x402tookit.com/engine-calc",
"description": "Engine displacement in cc, litres and cubic inches from bore, stroke and cylinders; compression ratio and mean piston speed.",
"outputSchema": {
"input": {
"type": "http",
"method": "GET",
"queryParams": {
"rpm": 6000,
"bore": 86,
"unit": "mm",
"stroke": 86,
"cylinders": 4,
"clearanceVolumeCc": 49.9
}
},
"output": {
"asOf": "2026-10-11T14:38:36.873Z",
"boreMm": 86,
"design": "square",
"source": "computed locally",
"reasons": [
"Displacement = pi / 4 x bore^2 x stroke x cylinders. Compression ratio = (swept volume + clearance volume) / clearance volume. Mean piston speed = 2 x stroke x RPM / 60.",
"1 cubic inch = 16.387064 cc."
],
"summary": "4 cylinders of 86 x 86 mm displace 1998 cc (2 L, 122 cubic inches); square. Compression ratio 11.01:1. Mean piston speed at 6000 RPM is 17.2 m/s.",
"verdict": "COMPUTED",
"degraded": false,
"strokeMm": 86,
"cylinders": 4,
"disclaimer": "Screening signal computed from the named public source. Not financial, legal or investment advice; provided as is. Verify at the source before acting.",
"notChecked": [
"the actual compression the engine makes: the static ratio ignores valve timing, boost and head-gasket thickness unless you include them in the chamber volume",
"knock limits and fuel octane for a given ratio",
"…2 more"
],
"displacementCc": 1998.23,
"boreStrokeRatio": 1,
"compressionRatio": 11.01,
"meanPistonSpeedMs": 17.2,
"displacementLitres": 1.998,
"compressionRatioText": "11.01:1",
"meanPistonSpeedFtMin": 3386,
"displacementCubicInches": 121.94,
"displacementPerCylinderCc": 499.557
}
},
"maxAmountRequired": "20000",
"maxTimeoutSeconds": 300
},
{
"asset": "0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359",
"extra": {
"name": "USD Coin",
"version": "2"
},
"payTo": "0xb531320805C5BED1D46AEaDcF4F008FDF172DBDa",
"scheme": "exact",
"network": "polygon",
"mimeType": "application/json",
"resource": "https://automotive-calc.x402tookit.com/engine-calc",
"description": "Engine displacement in cc, litres and cubic inches from bore, stroke and cylinders; compression ratio and mean piston speed.",
"outputSchema": {
"input": {
"type": "http",
"method": "GET",
"queryParams": {
"rpm": 6000,
"bore": 86,
"unit": "mm",
"stroke": 86,
"cylinders": 4,
"clearanceVolumeCc": 49.9
}
},
"output": {
"asOf": "2026-10-11T14:38:36.873Z",
"boreMm": 86,
"design": "square",
"source": "computed locally",
"reasons": [
"Displacement = pi / 4 x bore^2 x stroke x cylinders. Compression ratio = (swept volume + clearance volume) / clearance volume. Mean piston speed = 2 x stroke x RPM / 60.",
"1 cubic inch = 16.387064 cc."
],
"summary": "4 cylinders of 86 x 86 mm displace 1998 cc (2 L, 122 cubic inches); square. Compression ratio 11.01:1. Mean piston speed at 6000 RPM is 17.2 m/s.",
"verdict": "COMPUTED",
"degraded": false,
"strokeMm": 86,
"cylinders": 4,
"disclaimer": "Screening signal computed from the named public source. Not financial, legal or investment advice; provided as is. Verify at the source before acting.",
"notChecked": [
"the actual compression the engine makes: the static ratio ignores valve timing, boost and head-gasket thickness unless you include them in the chamber volume",
"knock limits and fuel octane for a given ratio",
"…2 more"
],
"displacementCc": 1998.23,
"boreStrokeRatio": 1,
"compressionRatio": 11.01,
"meanPistonSpeedMs": 17.2,
"displacementLitres": 1.998,
"compressionRatioText": "11.01:1",
"meanPistonSpeedFtMin": 3386,
"displacementCubicInches": 121.94,
"displacementPerCylinderCc": 499.557
}
},
"maxAmountRequired": "20000",
"maxTimeoutSeconds": 300
}
],
"x402Version": 1,
"alsoAvailable": {
"llms": "https://automotive-calc.x402tookit.com/llms.txt",
"catalog": "https://automotive-calc.x402tookit.com/catalog",
"message": "Automotive Calculators has 10 pay-per-call endpoints (Car math for agents: tire size and speedometer error, gearing and RPM, trip fuel, EV efficiency, towing, depreciation, lease versus buy, engines and braking.), from $0.02 a call. See the full menu and send your agents our way.",
"openapi": "https://automotive-calc.x402tookit.com/openapi.json",
"related": [
{
"url": "https://automotive-calc.x402tookit.com/ev-efficiency",
"path": "/ev-efficiency",
"what": "EV efficiency in kWh per 100 miles, miles per kWh, Wh per km and MPGe, range from battery…",
"price": "$0.02"
},
{
"url": "https://automotive-calc.x402tookit.com/fuel-trip-cost",
"path": "/fuel-trip-cost",
"what": "Trip fuel and cost for legs with different mileage (city, highway), tank range, refuel st…",
"price": "$0.02"
},
{
"url": "https://automotive-calc.x402tookit.com/gear-rpm",
"path": "/gear-rpm",
"what": "Engine RPM at a road speed (or speed at an RPM) from tire size, axle ratio and transmissi…",
"price": "$0.02"
}
]
}
}Accepts
The payment requirements as published to the catalog. Read the live 402 before paying — a price here is a claim, not a quote.
0.02USDC≈ $0.02 USD
on Base · exact scheme
Pay 0.02 USDC on Base to 0xb531…2DBDa. The signed payment is good for 5 minutes.
- Paid to
- 0xb531…2DBDa
- USD Coin contract
- 0x8335…02913
- Payment window
- 5 minutes
- As published
- 20000 smallest units
20000units
on solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp · exact scheme
That figure is in the token’s smallest units. Roundhouse does not hold this contract’s decimals, so it is shown as published rather than converted.
- Paid to
- DUPiup…eEm8s
- Token contract
- EPjFWd…TDt1v
- Payment window
- 5 minutes
20000units
on Polygon · exact scheme
That figure is in the token’s smallest units. Roundhouse does not hold this contract’s decimals, so it is shown as published rather than converted.
- Paid to
- 0xb531…2DBDa
- Token contract
- 0x3c49…c3359
- Payment window
- 5 minutes
20000units
on Arbitrum · exact scheme
That figure is in the token’s smallest units. Roundhouse does not hold this contract’s decimals, so it is shown as published rather than converted.
- Paid to
- 0xb531…2DBDa
- Token contract
- 0xaf88…e5831
- Payment window
- 5 minutes
The catalog’s raw entry
[
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"extra": {
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"payTo": "0xb531320805C5BED1D46AEaDcF4F008FDF172DBDa",
"amount": "20000",
"scheme": "exact",
"network": "eip155:8453",
"maxTimeoutSeconds": 300
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{
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"extra": {
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"payTo": "DUPiupXtuox38dcGoXUKer5mAydCzmaHjrbQ66qeEm8s",
"amount": "20000",
"scheme": "exact",
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{
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"extra": {
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"payTo": "0xb531320805C5BED1D46AEaDcF4F008FDF172DBDa",
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{
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"payTo": "0xb531320805C5BED1D46AEaDcF4F008FDF172DBDa",
"amount": "20000",
"scheme": "exact",
"network": "eip155:42161",
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]Extensions
{
"bazaar": {
"info": {
"input": {
"type": "http",
"method": "GET",
"queryParams": {
"rpm": 6000,
"bore": 86,
"unit": "mm",
"stroke": 86,
"cylinders": 4,
"clearanceVolumeCc": 49.9
}
},
"output": {
"type": "json",
"example": {
"asOf": "2026-10-11T14:38:36.873Z",
"boreMm": 86,
"design": "square",
"source": "computed locally",
"reasons": [
"Displacement = pi / 4 x bore^2 x stroke x cylinders. Compression ratio = (swept volume + clearance volume) / clearance volume. Mean piston speed = 2 x stroke x RPM / 60.",
"1 cubic inch = 16.387064 cc."
],
"summary": "4 cylinders of 86 x 86 mm displace 1998 cc (2 L, 122 cubic inches); square. Compression ratio 11.01:1. Mean piston speed at 6000 RPM is 17.2 m/s.",
"verdict": "COMPUTED",
"degraded": false,
"strokeMm": 86,
"cylinders": 4,
"disclaimer": "Screening signal computed from the named public source. Not financial, legal or investment advice; provided as is. Verify at the source before acting.",
"notChecked": [
"the actual compression the engine makes: the static ratio ignores valve timing, boost and head-gasket thickness unless you include them in the chamber volume",
"knock limits and fuel octane for a given ratio",
"…2 more"
],
"displacementCc": 1998.23,
"boreStrokeRatio": 1,
"compressionRatio": 11.01,
"meanPistonSpeedMs": 17.2,
"displacementLitres": 1.998,
"compressionRatioText": "11.01:1",
"meanPistonSpeedFtMin": 3386,
"displacementCubicInches": 121.94,
"displacementPerCylinderCc": 499.557
}
}
},
"schema": {
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"required": [
"input"
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"properties": {
"input": {
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"required": [
"type",
"method"
],
"properties": {
"type": {
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"const": "http"
},
"method": {
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"GET"
],
"type": "string"
},
"queryParams": {
"type": "object",
"required": [
"bore",
"stroke",
"cylinders"
],
"properties": {
"rpm": {
"type": "number",
"description": "Engine speed, for mean piston speed"
},
"bore": {
"type": "number",
"description": "Cylinder bore diameter"
},
"unit": {
"type": "string",
"description": "mm (default) or in for bore and stroke"
},
"stroke": {
"type": "number",
"description": "Piston stroke"
},
"cylinders": {
"type": "integer",
"description": "Number of cylinders, 1 to 16"
},
"clearanceVolumeCc": {
"type": "number",
"description": "Combustion chamber volume per cylinder at top dead centre, cc, for the compression ratio"
}
}
}
},
"additionalProperties": false
},
"output": {
"type": "object",
"required": [
"type"
],
"properties": {
"type": {
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},
"example": {
"type": "object",
"properties": {
"asOf": {
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"null",
"string"
]
},
"boreMm": {
"type": [
"null",
"number"
]
},
"design": {
"type": [
"null",
"string"
]
},
"source": {
"type": [
"null",
"string"
]
},
"reasons": {
"type": [
"array",
"null"
],
"items": {
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}
},
"summary": {
"type": [
"null",
"string"
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},
"verdict": {
"type": [
"null",
"string"
]
},
"degraded": {
"type": [
"boolean",
"null"
]
},
"strokeMm": {
"type": [
"null",
"number"
]
},
"cylinders": {
"type": [
"null",
"number"
]
},
"disclaimer": {
"type": [
"null",
"string"
]
},
"notChecked": {
"type": [
"array",
"null"
],
"items": {
"type": "string"
}
},
"displacementCc": {
"type": [
"null",
"number"
]
},
"boreStrokeRatio": {
"type": [
"null",
"number"
]
},
"compressionRatio": {
"type": [
"null",
"number"
]
},
"meanPistonSpeedMs": {
"type": [
"null",
"number"
]
},
"displacementLitres": {
"type": [
"null",
"number"
]
},
"compressionRatioText": {
"type": [
"null",
"string"
]
},
"meanPistonSpeedFtMin": {
"type": [
"null",
"number"
]
},
"displacementCubicInches": {
"type": [
"null",
"number"
]
},
"displacementPerCylinderCc": {
"type": [
"null",
"number"
]
}
}
}
}
}
}
}
}
}Provenance
- Seen in the source catalog
- 2026-10-20 20:45Z
- Last indexed by Roundhouse
- 2026-10-22 19:30Z
- Last enriched (probe, favicon, geo)
- 2026-10-20 22:45Z
- x402 version
- 2
- Max timeout
- 300s
- Liveness probe
- HTTP 402
Hand this page to an agent
Copy the prompt and paste it into Claude, an MCP client or your own agent — it will vet this service and call it over the free read API. No key, no account.
GET api.roundhouseai.io/v0/endpoints
This endpoint's own trailing-30-day call count, as published by the upstream catalog and snapshotted daily. 4 snapshots so far. Verified volume counts only settlements with an on-chain EIP-3009 marker.
Show the promptHide the prompt
Using Roundhouse, look up the x402 service Automotive Calculators and tell me whether it is worth paying: what a call costs, whether the endpoint answered when last probed, and what its payment record actually shows. curl -s 'https://api.roundhouseai.io/v0/endpoints?q=Automotive%20Calculators' curl -s 'https://api.roundhouseai.io/v0/merchants/<the payTo wallet returned above>' Then call it: read the price from the live 402 at https://automotive-calc.x402tookit.com/engine-calc, never from a cached figure, and pay with an x402 client. The /v0 API needs an API key (`authorization: Bearer rh_live_…`) on everything except /v0/unified* and /v0/endpoints. Either pay over x402 (mint a personal key for $0.01 at GET https://api.roundhouseai.io/v0/test/x402), or ask me for an organization key, which I create at https://roundhouseai.io/dashboard/connections. If you have neither, ask before going further. If you do not have Roundhouse tools or skills installed, read https://roundhouseai.io/skill.md first — it is the whole procedure.