Hi everyone,

I'm lookin to get 380-400bhp out of my 98 Impreza Type R . At the moment it's running 320bhp with the following mods:

2.0 Type RA Closed Deck Block
JE Forged Pistons
ARP Head Studs
Eagle Forged Con-Rods
Autobahn88 FMIC
Fuel Lab adjustable Fuel Regulator
Walbro Uprated Fuel Pump
Apexi PFC and Commander
H&S decat up/down pipe (wrapped)
Scooby Sport cat back
HKS BOV
HKS Induction Kit

It's running 1.5 bar.

Would I be right in thinking that I need some 550cc injectors, an 18g turbo and a remap? Is anything missing?

Also, am I going to notice a big difference with the extra 60/80bhp or would it not be worth the money?

Any info please

 

Tubular headers would also be on my list, plus if you want 380HP on pump fuel you may want to consider the 20g

I'm sure your mapper can advise though

 

as above to be on the safe side opt for a 20g as that can get close to 400 on pump fuel.

 

Would you not be risking the gearbox at that sort of level?

 

550cc injectors and a 20G turbo.

Budget for a replacement gearbox.

Ns04

 

What power will the gear box take? Don't want to be replacing that in a rush now do I?

Could I have a 18g and not change the injectors and get a safer 360bhp?

I don't really know that much about it all so anything anyone can tell me would be a great help!

 

I think that 350 is about the limit on a standard gearbox but very much depends on your driving style. I have the same car as you running about the same power and am wary of trying for more as uprated gearboxes are expensive!

 

Depends on several factors mate, including some that may be out of your control i.e. how the car has been treated before you owned it. With sympathetic mapping and driving style the low 300s ft lbs should be ok, anything above 350lbs and I'd expect to replace sooner rather than later tbh... No point having the poke if you're scared to use it.

Budget 2k for 6 speed from new age Sti, nearer 3 for PPG gearset.

Best,

Ns04

 

£3k for PPG assuming you do not need a donor TY754 box, billet forks, clutch etc.. Then the price keeps going up...

 

sounds pretty simple then... leave well alone

 

Also, are you really running 1.5bar?

With those mods, I'd have thought around 1.3 would do it for the power level you claim?

Ns04

 

If you are running 1.5 bar currently in the midrange then a 20G is not going to make a massive change to your midrange torque output (torque kill boxes, not power) what it will do is hold that level of torque far higher in the rpm range resulting in a higher power figure.
Typically the 20G will flow 50bhp more air than the VF24 on an Sti4.

Sti version 3 onwards gearboxes are stronger than UK versions and would normally cope with circa 350lbft torque and 400bhp without issue.

Andy

 

Right then, I'm still being thick here. Could I put the turbo on without the injectors? If so what sort of power difference would there be?

Also everyone seems to sey about a tubular manifold? I've heard these crack all the time and have to be welded?

 

the gt-spec style manifolds seam to get good reports

 

No, you would need to upgrade injectors to achieve the benefits of the bigger turbo. As mentioned, the GT spec headers do not have any of the cracking issues associated with some of the cheaper designs, they have double wall slip joints to allow for expansion.

More reading on your model here - Sti v3-4