How much deposit should I take on a diesel or performance build?
Short answer
Fifty percent up front, nonrefundable once parts are ordered, with progress payments tied to milestones on anything over a few thousand dollars. Anything less and you're financing someone else's project car with your own cash flow.
The deposit isn't a formality, it's your parts budget
A build job is different from a repair. You are ordering turbos, injectors, tuning hardware, and machine work weeks before you collect the balance. If you don't take a real deposit, you're floating the customer's project on your own credit card and hoping they don't disappear when the invoice comes due.
Fifty percent covers parts and gets skin in the game from the customer. On anything running past $10,000 or a few months of calendar time, break it into three payments: deposit to start and order parts, a progress payment at the halfway mark, and the balance due before the vehicle leaves your lot, not after.
Make it nonrefundable once you've spent it
State plainly that the deposit becomes nonrefundable the moment you place a parts order or start machine work, because you can't un-order a custom cam or a set of injectors. Customers who balk at that line are telling you something about how the rest of the job is going to go.
Put the schedule in writing before a single bolt turns. A text message thread is not a payment agreement. A one-page build agreement with dollar amounts and dates is.
Hold the line when a regular asks for an exception
Your best customers will sometimes ask to skip the deposit because you know them. That's exactly the customer relationship where a scope change six weeks in gets forgiven in your head instead of billed, because you already bent the rules once. Same deposit, every build, every customer.
Cash exposure with and without a deposit
| Parts and machine work cost, mid-size engine build | $8,500 |
|---|---|
| Deposit collected at 50% | $4,250 |
| Shop cash exposure with deposit | $4,250 |
| Shop cash exposure with no depositfully at risk until final invoice is paid | $8,500 |
The math: Cash exposure equals total parts and outside labor cost minus whatever deposit you've actually collected before spending it.
Build deposit and progress payment terms
Attach to every build quote before ordering parts.
BUILD PAYMENT SCHEDULE Project: __________________ Estimated total: $__________ 1. Deposit of 50% ($__________) due before parts are ordered or work begins. This deposit is NONREFUNDABLE once parts are ordered or machine work has started. 2. Progress payment of 25% ($__________) due at the halfway point of the build, defined as: __________________. 3. Final balance of 25% ($__________) plus any approved change orders due in full before the vehicle is released. 4. Storage fees of $______/day begin 5 business days after we notify you the vehicle is ready, whether or not final payment has been made. 5. Any change in scope, parts, or specs from the original quote will be documented in writing and priced separately before work continues. Customer signature: __________________ Date: __________
Where owners get this wrong
- Taking a small flat deposit regardless of job size instead of a percentage.
- Calling the deposit refundable to be polite, then eating a full parts order when the customer disappears.
- Not tying progress payments to a defined milestone, so the second payment never has a clear trigger.
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