I've currently got a ~290bhp MY93 WRX and have been planning my upgrades to ~350 for a while but I've been thinking about what I really want.

I'm not sure I need 350bhp (although it sounds like a nice figure). My car is 99% street driven. In fact, I haven't taken it near a trackday yet, although I'd like to. So what I really want is loads of accessible power, or I suppose more accurately, torque.

I spend most of my time in the 2000 - 5000 rpm range and this means I'm not making best use of the turbo. Obviously, when I do hit my favourite back roads, I make better use of the available power but thats not as often as I'd like.

So, the question is: can the Scooby engine be tuned to make huge mid-range torque, with little turbo lag?

Edited to say: no 2.5's, makes insurance too nightmarish

Some ideas of spec would be nice

 

A TD04 or VF35 might be an improvement? As would good breathing and strong boost control - gear judge on AVC-R can liven things up a lot in the real world.

If you have to stick to 2.0, the short ratio box with 8000 RPM STi long block would give you a wider power band, revs and gearing being the proxy for torque. AVCS and twin scroll would finish it and put the icing on the powerband cake. It is torque at the wheels you want and these are ways to get it.

Hate to say it, but a 2.5 block transplant despite the insurance difficulties is the best way to get what you want with the minimum of hardware.

 

I'm not keen on a TD04 as they tend to feel strangled at the top end (unless this can be overcome). How does a VF35 compare to the 04? I like the idea of a twin scroll, but are they priced realistically?

 

VF35 is in between a TD04 and TD05 in sizing. You can't have it all simply by changing to another bolt on turbo without any other changes, there will be compromise or more expense (eg twin scroll, AVCS, 8000 RPM engine). If you could sort the insurance, the far better torque delivery/power band would only require a remap, headgaskets, 2.5 block and replacement fluids, as I say, by far the cheapest solution. The cost is in sorting everything else out to take the higher power you'll then want, if you stick at the same level and expand the power band with the same peak numbers it is cheap. But you have the insurance issue.

 

I know you're right, I reckon a 2.5 with TD05, good intercooling, uprated fuel system and a conservative map would be best for a road car. I suppose I'd better get searching for 2.5 friendly insurers. Or an AMG Merc