Short answer: All three JZ smart coil options — IGN1A, 1NZ/1ZZ, and R35 — solve the same problem (weak, failure-prone stock JZ coils under boost), but they trade off differently between output and cosmetics. Straight from ASE's own testing: IGN1A makes the most power but will not fit under a valve cover (factory or billet). R35 and 1NZ/1ZZ both tuck under covers cleanly, with R35 sitting between the other two on output. If a clean, hidden look matters to you, that fitment question — not just price — should drive your decision.
This article is based on our own product video covering this exact comparison, updated with current pricing and product options.
What's a "smart coil," and why upgrade?
Stock JZ coils are a common weak point once you're running real boost — they're prone to breaking down under the higher cylinder pressures of a built engine. A "smart coil" has its ignition module built directly into the coil body (as opposed to a "dumb" coil that needs an external ignitor box), so all three options here are simple bolt-on upgrades once fitted to the right bracket.
The #1 question: does it fit under a valve cover?
This is the question ASE gets asked more than any other on these kits — and the answer is different for each option, whether you're running factory Toyota covers or a set of billet covers:
- 1NZ / 1ZZ: Fits under both factory VVTi and Non-VVTi covers, and under billet covers. Low install height, no spacers needed.
- R35: Also fits under factory and billet covers — sits even lower than the 1NZ/1ZZ install height.
- IGN1A: Will not fit under any cover, factory or billet. The bracket itself mounts higher than the valve cover line, so there's no version of this that tucks away — that's a physical limitation of the bracket design, not a fitment issue to troubleshoot.
If you want a clean engine bay that doesn't visually announce what you're running, 1NZ/1ZZ or R35 are your only real options. If you don't care about that and want maximum output, IGN1A is worth the tradeoff.
Output ranking
Straight from ASE's own testing across all three: IGN1A produces the highest ignition output of the three by a clear margin — it supports a larger spark plug gap and a meaningfully more powerful spark discharge per cycle, which is why it's the choice for builds chasing maximum power. R35 lands in the middle — a genuine step up from 1NZ/1ZZ, without giving up cover clearance, and at a lower cost than IGN1A's turnkey option. 1NZ/1ZZ is the entry option of the three on output, though still a real upgrade over stock coils, at the lowest price point.
Quick comparison
| 1NZ / 1ZZ | R35 | IGN1A | |
|---|---|---|---|
| Ignition output | Entry-level of the three | Middle — clear step up from 1NZ/1ZZ | Highest |
| Fits under valve cover (factory or billet)? | Yes | Yes — lowest install height of the three | No — will not clear any cover |
| Coil source | Genuine Toyota OEM (Denso 673-1306, shared by 1NZ and 1ZZ engines) | Genuine Nissan R35 GT-R VR38 coil packs (2008–2019) | Aftermarket standard (AEM, Haltech, Megasquirt, Firecore) |
| Retains crossover intake? | No | No | Yes |
| Connector style requirement | Flat connector coils only | Genuine R35 connector included | Brand-dependent |
| Bracket-only price | $174.99 | $199.99 | $149.99–$174.99 |
| Full turnkey (bracket + coils + harness) | $749.99 | $799.99 | $824.99 |
1NZ / 1ZZ
The budget entry point — lowest output of the three, but the lowest cost, and it fits under both factory and billet covers with no spacers needed. It repurposes the genuine Denso 673-1306 coil shared by Toyota's 1NZ and 1ZZ engine families (Corolla, Matrix, and others), which is affordable and widely available. Two things to know before ordering: it only works with flat-connector coils (angled connectors won't orient correctly between the valve covers), and it does not retain your OEM crossover intake manifold.
| Application | Price | Shop |
|---|---|---|
| 1JZ VVTi | $174.99–$749.99 | View |
| 1JZ Non VVTi | $174.99–$749.99 | View |
| 2JZGE (one-piece bracket) | $174.99–$749.99 | View |
Each listing offers Bracket Only, Bracket & Coils, or Bracket + Coils + Relay Harness options.
R35
The middle ground — a genuine step up in output from 1NZ/1ZZ, while still tucking cleanly under both factory and billet valve covers (the lowest install height of the three). ASE's R35 bracket runs genuine Nissan R35 GT-R VR38 coil packs (2008–2019), which are easier to source and less costly than OEM 1JZ/2JZ coils while offering a real output upgrade. Billet 6061 aluminum, made in the USA, with shorter coil stalks and boots for a cleaner fit. Like the 1NZ/1ZZ option, it does not retain the OEM crossover intake.
| Option | Application | Price | Shop |
|---|---|---|---|
| Bracket only | Non-VVTi or VVTi | $199.99 | View |
| Bracket & coils | Non-VVTi or VVTi | $649.99 | |
| Bracket, coils & relay harness | Non-VVTi | $799.99 |
Fits 1JZGTE (Non-VVTi), 2JZGTE (VVTi & Non-VVTi), and 2JZGE (VVTi only — not compatible with 2JZGE Non-VVTi).
IGN1A
The max-power option — highest ignition output of the three, at the cost of not fitting under any valve cover. IGN1A isn't a single OEM coil, it's an aftermarket mounting standard multiple brands build to, which is what makes it flexible. ASE's bracket is verified with AEM, Haltech, and Megasquirt coils, and the turnkey kit bundles Firecore coils with 8.5mm plug wires. Bracket options are available for both 1JZ and 2JZ, VVTi and Non-VVTi, in Matte Silver or Black finishes, with Standard or Quick Release bracket styles.
| Application | Price | Shop |
|---|---|---|
| 1JZ Non VVTi (bracket only) | $149.99 | View |
| 1JZ VVTi (bracket only) | $149.99 | View |
| 2JZ Non VVTi turnkey (bracket + Firecore coils + harness) | $824.99 | View |
Which should you choose?
Choose 1NZ/1ZZ if:
- Budget is the priority — it's the lowest-cost full turnkey option
- You want a tucked-under-cover look but don't need R35-level output
- You have (or can easily source) flat-connector coils
Choose R35 if:
- You want a clean, tucked-under-the-cover look without giving up much output versus IGN1A
- You want a genuine, well-proven high-output OEM coil (GT-R VR38) that's easier and cheaper to source than OEM JZ coils
- You want the middle ground on both price and output
Choose IGN1A if:
- Maximum ignition output is the priority, and you're fine with the bracket being visible (no cover)
- You want to run a larger spark plug gap for a stronger discharge per cycle
- You want the flexibility to pick your coil brand (AEM, Haltech, Megasquirt)
- You need to retain your OEM crossover intake manifold
Common questions
Which of these fits under a valve cover?
1NZ/1ZZ and R35 both fit cleanly under factory Toyota covers (VVTi and Non-VVTi) and billet covers, with no spacers needed. IGN1A does not fit under any cover — the bracket mounts higher than the cover line by design, so this isn't something that can be worked around with spacers or a different cover.
Which coil makes the most power?
IGN1A has the highest ignition output of the three, supporting a larger plug gap and stronger spark discharge. R35 is the middle option — a real step up from 1NZ/1ZZ. 1NZ/1ZZ is the entry-level output of the three, though still a genuine upgrade over stock coils.
Do any of these retain the OEM crossover intake?
Only IGN1A. Both 1NZ/1ZZ and R35 require removing the OEM crossover — factor that into your intake plans before choosing.
Does the R35 bracket work with my 2JZGE?
Only if it's VVTi — the ASE R35 bracket is not compatible with 2JZGE Non-VVTi. It does fit 1JZGTE (Non-VVTi) and 2JZGTE (both VVTi and Non-VVTi).
Can I use any coil brand with the IGN1A bracket?
ASE's IGN1A bracket has verified fitment with AEM, Haltech, and Megasquirt coils. Coils sourced from eBay or newer Mercury marine coils may or may not fit — confirm compatibility before ordering if you're supplying your own coils.
Does VVTi vs. Non-VVTi matter for fitment?
Yes, across all three options. VVTi and Non-VVTi heads have different clearances, so make sure you order the bracket matched to your specific head, not just your engine code.
Building a full JZ swap?
Coil upgrades are one piece of a bigger build. See our 1JZ vs 2JZ comparison guide if you're still deciding on an engine, or our CD009 Compatibility Guide if you're planning the transmission side of the swap.