In the world of large-cube Japanese turbo engines, the Nissan RB-series and Toyota JZ-series are the most common choice to modify. But there’s another engine that lurks just outside the spotlight – the Toyota 7M-GTE. At 3-litres, the 7M-GTE matches the displacement of any other Japanese turbo engine and boasts a DOHC, multi-valve head for similarly efficient breathing characteristics. Really, there’s no reason why the 7M-GTE can’t kick out some huge power numbers – and Sam Rigoli of TRP (Tony Rigoli Performance) is here to show us how!
Believe it or not, Sam’s highly modified 7M is mounted in the snout of a Nissan R32 Skyline GTS. Why? Well, when you’ve seen a thousand RB engines and you want something a bit different, why the heck not? So when a customer’s 7M-GTE came up for sale, Sam jumped on the opportunity and got stuck into slotting it in place of the R32 RB engine. The conversion was pretty difficult, requiring new mounts and cross member, a modified sump and some stuffing around with coolant passages, linkages and wiring.
In its current configuration, the 7M-GTE is set up to run big boost together with nitrous assistance all the way through the rev range. So it’s no surprise the engine has been built to high-performance specs. At the bottom the engine runs the standard crank with Crower rods and Aries forged pistons providing a static compression ratio around 8:1. The 7M has a reputation for popping head gaskets but Sam has no such worries thanks to an ARP stud kit, copper head gasket and O-ringed head and block.
Despite the level of performance being extracted, the standard Toyota DOHC head remains untouched – it can’t be too bad, eh? The only changes are firmer valve springs, which are better suited to the frequent high rpm operation. Sam couldn’t find aftermarket springs to suit the 7M but a set of aftermarket 4A-GE springs do the same job. The standard camshafts are retained but, as seen in this photo, there are adjustable cam sprockets. Interestingly, these are left at the standard timing – Sam says he hasn’t seen much of a gain by altering cam timing.
And now to the real power pushers – the turbocharger and nitrous system.
Sam had his brother, Domenic, whip up a custom tubular exhaust manifold which allowed fitment of a Garrett turbo and external wastegate. The turbocharger is a Garrett GT42R teamed with an Innovative 52mm external ‘gate. Both breathe into a 3 ½ inch mandrel exhaust with a straight-through muffler.
In its current configuration, the engine is run to a maximum of 29 psi boost and charge-air cooling is left to an off-the-shelf A’PEXi core designed to suit the R32. Three inch plumbing runs to and from the ‘cooler and you won’t find a blow-off valve. The inlet to the turbocharger is usually protected by a K&N pod filter but Sam has recently run the car without out it - he says it doesn’t make much difference.
The standard 7M intake manifold has been replaced with a custom manifold that’s different to say the least. What you’re looking at is a pair of fuel surge tanks welded together with a Ford throttle body hung off one end. Now that’s creative!
For that little bit of extra oomph, Sam can rely on a ZEX wet manifold nitrous system. When the boot-mounted nitrous bottle is opened and a micro-switch on the throttle detects 100 percent WOT, a 100hp shot of gas is injected into the plumbing following the intercooler. Initially, the nitrous was solely intended to bring the turbocharger on boost but that idea was soon abandoned – it’s now run all the way through the rev range at WOT.
Coordinating fuel and ignition timing is a MicroTech programmable ECU. The fuel system kicks off with an in-boot fuel cell and a pair of Bosch Motorsport fuel pumps. Larger-than-standard lines take fuel to six Mazda 13B Turbo injectors and pressure is maintained by a Malpassi. The ignition is an impressive arrangement with six Bosch coils fired by MicroTech igniters.
Sam’s R32 is built as a quarter mile machine and an auto transmission was required for the task. A Ford C4 auto trans has been fully tricked with billet internals, a trans brake and an external fluid cooler. The torque converter provides a 4000 rpm stall speed to get the 7M turbo engine really boosting off the line. A custom heavy-duty tailshaft extends rearward to a Nissan S15 200SX/Silvia mechanical diff. Fitment of the S15 diff required modification to the end-plates on the existing inner CV joints.
With an all-up weight of 3150lb (1432kg) including driver, Sam’s Skyline has had minimal effort invested in weight reduction. Some of the dashboard has been removed, but this is more than offset by the fitment of a complete GT-R interior and six-point roll cage. The suspension could also be improved over the current set-up - the recently installed Tein suspension is more about handling than straight-line performance.
So what numbers are we talking from this heavily tuned 7M-GTE?
Well, on the TRP Dyno Dynamics chassis dyno Sam has seen a massive 570hp (425kW) at the back wheels. This equates to somewhere around 850hp (634kW) at the flywheel – perhaps closer to 900hp (671kW), depending on the amount of slip through the transmission and tyre-to-dyno interface. This output was achieved with 29 psi boost, a 100hp nitrous shot and Martini race fuel. Peak power arrives at around 6500 rpm and peak torque isn’t far below – full boost doesn’t arrive until around 5000 rpm... The rev limit is set at around 7500 rpm.
Mounted in the nose of the Skyline, the Toyota turbo engine easily runs down the quarter mile in the 9 second bracket. The best time to date is a 9.58 at 140 mph – though, note that a higher terminal speed has been achieved on another run. Of course, these times are achieved on slick tyres – 26 x 10 Mickey Ts.
Despite having what is probably the most powerful 7M-GTE in Australia, Sam reckons there’s plenty of room left for more grunt. A spare cylinder head is currently being ported and fitted with all the good bits (including cams) and it’s likely the intake plenum could be refined. Oh, and a different turbo is worth a try. Reliability is unlikely to be a problem as Sam has already found the engine’s limit – it seems pistons crack in half when boost pressure is pushed to 38 psi...
So there you have it – the unloved 7M-GTE engine making least 850hp (634kW) at the flywheel using an untouched cylinder head. There’s something for RB and JZ engine fans to think about...
Sam’s mega power 7M-GTE engine has now been sold for fitment into a customer’s Datsun ute! If all goes to plan, Sam will start fresh with another 7M and take it ‘all the way’ – stay tuned...