Turbo LQ4 questions
98mm turbo
317 heads
sloppy stage 2 camshaft
pac1218 springs
new bearings all around
stock bore (honed)
Im just wondering if forged pistons are worth it or if the stock pistons can handle boost. I’m wanting to make around 550-600whp.
They market them as 98mm to people who don't know any better.
They're technically a 68mm turbo measured at the inducer, which is where turbos are normally measured.
An 80mm Borg Warner S480 is ~110mm measured at the exducer.
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They market them as 98mm to people who don't know any better.
They're technically a 68mm turbo measured at the inducer, which is where turbos are normally measured.
An 80mm Borg Warner S480 is ~110mm measured at the exducer.
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Its also a hard turbo to upgrade from because the abnormal V-band diameter on the turbine requires you to fab an entire new downpipe, or at least resize/reflange the current one.
Its a turbo you use because you got it for free or because you're trying to do a $500-all-in budget turbo setup.
Even a $450 cast S475 from VS would be a significant step up.
Better to run what you have and then upgrade later, this way you are able to find out if you are happy with it or if you want/need more power
My first turbo build was like you, only looking 550-600whp, started with an itty bitty TC7868 which was fun but choked at 5,500rpm around 6-7 lbs.
So in went an old school T7875 at the same 6-7 lbs. and an extra fuel pump, that lasted about one summer then got boring.
So I upped the boost to 12-13 lbs., now we're having fun, threw it on a stingy Mustang dyno and laid down almost 700whp, drove it like that for years before selling the car.
Point being, 550-600whp might not satisfy you very long, where do you think you'll end up, plan ahead, plan for a T6 flange perhaps, then your options are many and affordable.
Space requirements for the S-series turbos are the only limiting factor, my S484 is pretty big but **** an A does it look cool under the hood.









