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Renault 25 —
three PRV V6s under one bonnet

The big Renault saloon received three PRV V6s: the 2.7 injection (Z7V, 144 bhp) inherited from the Renault 30, the 2.5 turbo (Z7U, 182 then 205 bhp) — the very first turbocharged PRV, in 1985 — and the 2.8 injection (Z7W, 160 and 153 bhp). Each engine has its own file below.

3
PRV V6 ENGINES
144–205
BHP
1985
FIRST TURBO PRV
832
HEULIEZ LIMOUSINES
Engines

Five PRV codes, three engines

Every PRV V6 fitted to the Renault 25, code by code, with the engine file that details each one. All of them are Douvrin Z-codes: there was never a Renault 25-specific PRV.

Renault 25 2,458 to 2,849 cc · 144 to 205 bhp Every known code →
Z7V144 bhp
2,664 ccMechanical injectionNaturally aspiratedZ7V engine file →
R25 V6 injection, phase 1 — the Renault 30 TX's 2.7 litre carried over. The one starring in Dobermann (1997).
Z7U 702182 bhp
2,458 ccTurboBendix injectionZ7U engine file →
R25 V6 Turbo, 1985–1989 — the first turbocharged PRV V6, and with it the even-firing second generation. Also the engine of the Heuliez presidential limousine.
Z7U 700205 bhp
2,458 ccTurboFenix 3B injectionCatalysedZ7U engine file →
R25 V6 Turbo and Baccara V6 Turbo, from 1990 — the rare case of an engine that gained power when catalysed, thanks to a full re-tune. The V6 Turbo was very quickly reserved for the Baccara alone: the plain 205s of the first months are among the rarest of all.
Z7W 706160 bhp
2,849 ccElectronic injectionNaturally aspiratedZ7W engine file →
R25 V6 injection, 2.8 litre — the 2,849 cc with electronic injection, uncatalysed.
Z7W 707153 bhp
2,849 ccElectronic injectionCatalysedZ7W engine file →
Catalysed R25 V6 injection — the same 2.8 litre as the Espace V6's.
The engine that made history

“The fabulous turbo”

Under the bonnet from 1985, the 2,458 cc Z7U: 182 bhp with Bendix injection (Z7U 702), then 205 bhp with Fenix 3B injection on the catalysed version (Z7U 700) — the rare case of an engine that GAINED power with its catalyst, thanks to a complete re-tune. With it came the second generation of the PRV: a forged crankshaft with offset crankpins, and smooth running at last.

All the 2.5 turbo variants are on the Z7U engine file — and the period advertising plates are on the History page.

205
BHP · Z7U 700 · FENIX 3B · CATALYSED
2458
CM³
182
BHP (BENDIX)
12
VALVES
Two destinies

From the Élysée to the “French AMG”

The presidential limousine

Stretched 22.7 cm by Heuliez and armoured, the R25 Limousine — 2.7-litre (144 bhp) or 2.5 turbo (182 bhp) — carried François Mitterrand through both his terms. 832 were built between 1986 and 1988, on the phase 1 only; the motorcade was nicknamed “le gang des R25”. Full story in Pop culture.

The HAS preparation — ≈ 240 bhp

Around 1989, the young French outfit HAS reworked the V6 Turbo like AMG did Mercedes: turbo, intercooler, electronics and suspension revised, for around 240 bhp. Roughly ten built — a near-unfindable myth, detailed in Tuners.

And in the movies

A phase 1 R25 V6 injection (the 144 bhp 2.7, code Z7V) stars in Jan Kounen's cult 1997 film Dobermann — proof the Douvrin saloon crossed every register.

In the Journal

“Renault 25 V6 Turbo — the car of the PRV's second generation” · “the R25's AMG” — the Turbo (M6) TV report on the HAS preparation

In the workshop

What the manuals say about the R25 V6 Turbo

Four answers taken from our FAQ, each one read in the workshop documents of the Library. Several hundred more are in the full FAQ.

R25 V6 Turbo The full FAQ →
Turbo
At what pressure is the 205 bhp R25 V6 Turbo's turbo set?
A Garrett T3 with pressure-limiting valve, two check points: 320 ± 30 mbar for a rod travel of 0.38 ± 0.05 mm, then 480 ± 30 mbar for a travel of 4 ± 0.05 mm. The pressure in the manifold, read on the XR25 at full load on a road test, must be 1,870 +50/−10 mbar between 2,750 and 3,750 rpm — full throttle taken at 2,000 rpm and held, in 3rd or 4th — and 1,840 +50/−10 mbar at the maximum speed of 5,500 rpm, in 2nd or 3rd. Unlike the A610, whose figure is flat, this one eases off slightly at the top end. The bypass valve opens at 200 ± 20 mbar — a vacuum taken below the throttle, as its own page (folio 12-10) specifies; the specifications page prints “opening pressure”. The engine's safety switch cuts at a relative pressure of 1,300 +100/−0 mbar. Technical note 1558, folios 12-2 and 12-10.
1 300 mbar
At what pressure does the safety switch of an R25 V6 Turbo cut in?
1,300 mbar, and the check is simple: switch removed, connected to the Mot. 1014, an ohmmeter across its terminals. Below 1,300 mbar, R = 0 Ω; at 1,300 mbar and above, R = ∞ — the circuit opens. ⚠️ Do not transpose to the Alpine GTA V6 Turbo: its switch acts between 1.10 and 1.20 bar. Same function, two thresholds — and above all two opposite electrical logics. The GTA's check procedure is unambiguous: below 1.0 bar, R = ∞; between 1.0 and 1.1 bar, R = 0 Ω; and on the way back down the circuit reopens around 0.8 bar. Where the R25's switch OPENS on overboost, the GTA's CLOSES. A mechanic applying the R25's table to a GTA condemns a healthy switch — and the other way round. Also worth noting inside the GTA's own manual: its specifications page announces a threshold of 1.10 to 1.20 bar where its check page measures 1.0 to 1.1 bar. Technical note 1558 folio 12-13 · Alpine M.R.273 folio B-49a.
Ralenti
Can the idle of a fuel-injected PRV V6 be adjusted?
No, on the catalysed versions: the manual writes « not adjustable » in so many words, for both the speed and the CO. Renault 25 V6 Turbo 205 bhp (Z7U-700): 750 ± 50 rpm. Alpine A610 (Z7X-744): 700 ± 50 rpm. In both cases the figure is checked with the engine warm, between 80 and 100 °C, and CO must not exceed 0.5%. A drifting idle cannot be taken up on a screw: look to the regulating valve, the potentiometer or an air leak. N.T.1558 folio 12-1 · Alpine M.R.297 folio 12-1.
Contact coupé
What happens under the bonnet of a catalysed R25 V6 Turbo after the ignition is switched off?
Three independent systems set about limiting the temperature rise in the engine bay once the car stops. Turbocharger bearing cooling: an electric water pump, driven by a delay relay, keeps running for about 12 minutes after the engine and ignition are switched off, circulating coolant through the turbo bearings. Hot air extraction: a funnel-shaped deflector plate in front of the turbo is linked to a separate fan that draws the hot air away. And the main cooling fans: after the engine is stopped, a delay relay keeps them and the hot-air extractor available for about 12 minutes, but they only start if sensor 480 measures 100 °C in the engine bay; the two fans then run in series, at half speed, until the temperature falls to 95 °C or the relay cuts out after 12 minutes. A pump that stays silent after shutdown is therefore no small matter on this car: it is the turbo bearing cooling that is missing. ⚠️ Not to be confused with the Alpine GTA V6 Turbo, whose two fans keep running for two minutes after switch-off: two cars, two arrangements, two durations. Technical note 1558, folios 18-1 to 18-3 and 18-5 · Alpine M.R.273, folio B-49a.

Workshop documents in the Library

The period Pub et Trade professional data sheets, searchable page by page — sensor resistances, fuel and boost pressures, ignition, cylinder-head torque, valve clearances: Z7U-A700, 205 bhp · Z7U-A702, 182 bhp · Z7V, 144 bhp · Z7W-700, 160 bhp · Z7W-706/707, 153 bhp. And two Renault documents specific to the V6 R25: the M.R.249 supplement on unleaded fuel and Technical Note 1558 on the catalysed version.

On the forum

The Renault 25 has its own section on the forum — presentations, restorations, questions to members who drive one. Renault 25 section →

The turbo lineage

From this pioneer to the A610 and the Safrane Biturbo — the PRV's forced-induction story.

A610 file → All vehicles →