Thought I’d never do it again, but here I am. Turbo upgrade incoming for the Evo. On my old Evo, I went from the stock turbo to the HKS7460R, an incredible turbo that spooled quicker and made much more power up top than stock. That turbo blew its oil seals, dumping loads of oil into the intercooler piping – a total nightmare. From there, I went to an FP Green ball bearing, and while it made a ton of power, I hated the turbo lag, and everything about the car after that seemed to dull my enjoyment of it. Not long after, I parted out the car and bought this one.

While I’ve focused the build on suspension, handling, drivetrain, and my driving, I feel it’s finally time to upgrade the power. The stock turbo feels tired, to be honest, and the car feels slow. Indeed, comparing the build to other competitors, I’m probably short about 40whp. They are built motor guys with some pretty expensive bits, including full 3.5″ exhausts. I don’t plan on competing in Grid Life anymore, but between autox and the Lime Rock Park sessions, I am just gonna focus on the build and optimizing the car.

So the parts – the 71HTA (says 71HTZ, just the updated version). This turbo uses the stock housing, and just replaces the internal rotating assembly in it. Slightly smaller than the more common MHI18k turbo, it flows ~15-20% more than the OEM stock turbo. My stock turbo has felt a little tired lately, and I think this is the perfect refresh for it. In addition to flowing more, this turbo actually spools faster due to being billet and lighter components in the CHRA, according to FP. This means that not only will it spool a few hundred RPM faster on the dyno, but every time I get on the power. I opted for the 18psi wastegate, which will well cover my needs (25psi target) and retain the factory oil lines. The FP uses an 84mm compressor cover, meaning the intake has to be upgraded.

Given that I wanted to retain the MAF sensor, the option I went with was the ETS stock replacement intake. I think this intake is a great part in its own right. I’ve held off on changing the intake for the Evo, and now I’m glad I have. I plan on using my own air filter with this intake kit, and currently already have the MAF adapter, so this replaces the stock silicone tube with a metal part, with silicone couplers to mount everything properly. As FP does not make their own intake any longer, ETS is one of the few companies that offers an intake with the proper size fitting to mount to FP turbos. This intake should further decrease spool, and increases air flow from the intake to the turbo in a less turbulent fashion. I actually prefer this over the old FP full silicone intake – these (and any silicone intakes) have a chance of compressing/deforming under high pressure, which can result in devastation. I don’t believe the 10-20hp claims from this intake, but I do think it will pair very nicely with the 71HTA.

The final modification, which comes as a late addition, is the Artec stock replacement exhaust manifold. I actually held off on this manifold, opting for FP’s own race manifold. I held off because for all the aftermarket’s talk of better exhaust manifolds and better power and flow with ported intakes etc., I’ve never noticed a difference. This includes: the Boostin ported intake manifold, the Map 3″ stock replacement downpipe, and the FP race exhaust. None have done anything I’ve noticed in terms of power or spool. I purchased as supporting modifications for the flex fuel tune that I completed last year. That said, it seems the Artec exhaust manifold is the real deal. A lot of physics went into the design of this, and I’m not all that certain of how good it is, but I’ve been told it’s more akin to a tubular exhaust manifold, and it also removes some restrictive bends from stock (or FP’s). Again, better spool and more power.

I don’t think any of the mods I’ve done over the past few years have really picked up any power for me, and I think a lot of that comes to the bottleneck being the stock turbo. The 9 stock turbo is great, but parts like these increased flow manifolds, intakes, even the GSC S2s in the car have a lot more in them, and I think the bigger turbo will unlock the power from the build – especially up top. I’m not expecting massive peak gains from the car – may 30hp more on pump, 40hp more on E – still a lot to be fair. I am expecting most of the gain to be up top – past 5,500 RPMs, where the stock turbo starts to choke and the car feels like it falters. I’ll focus the tune to make sure we keep the torque low in the lower RPMs as well, so the car should feel pretty peppy. Save for going to a full 3.5″ exhaust with smaller mufflers/no resonators, this should be the quickest spooling setup for an autox Evo. Again, I’ve had the FP green ball bearing in the past, and have been disappointed in how late the power comes on, though it does come on strong. This should feel closer to the HKS7460r, hopefully without the reliability issues. I don’t remember how much power that turbo made, and it depends on the dyno, but I think that car made over 400whp. I think I’m making 330/360 pump/e85, respectively, on Alex’s dyno, so hoping for 360/400 with all the new bits, plus the improved powerband both in terms of spool and especially up top. I think these parts should really synergize to give a good jump in performance, and help me toward my goal of being the fastest street tire car at Lime Rock’s proving grounds.

Will update this post with dyno/power figures, and impressions.