[Hypergear Turbochargers and High flow Services Development thread]

12 hours ago, hypergear said:

Hi. ATR28 has standard cast wheels while the SS series has billet front wheels, SS class is also under rapid updates for better power and response. ATR28SS15 would be something similar to a GTX2867R, made 280rwkws P98 fuel internally gated on a built SR20det with 272/12 cams and very responsive to drive. 

Yeah I was thinking of getting the SS1.5 as I’m probably aiming for at least 300kw when I eventually go on E85.  
Do you have any idea about my last question?

[Hypergear Turbochargers and High flow Services Development thread]

Hey I've been looking to upgrade my current turbo which is a GT2860RS on my S15 and I have a couple of questions.

What's the difference between the ATR28 and then ATR28SS turbos?

Do they flutter well? I'm pretty sure my turbo has an anti-surge housing so it doesn't right now but I kinda miss my stock turbo flutter. Not a deal breaker if it doesn't.

Does the 28 number indicate the frame size, similar to the Garrett GT28 series? My friend told me since I'm tuned to a GT2860RS I can just replace it with a GTX2867R or something without a retune and run it without a problem if I don't change any boost settings but it won't be as efficient as it could be. I'm not sure if this is even true in the first place but I'm wondering if I could do something similar with the ATR28/SS. I would eventually tune it but I'm looking to freshen up the head with a valve springs kit, retainers, new VCT, etc first. I don't drive my car very hard either, I probably hit 5.5k rpm maybe once a twice a week.