Would the N/A rule of "LARGE PORT VOLUME=LAZY STREET HEAD/GOOD HIGH RPM HEAD" still apply to a boosted application? Specifically a quick spooling high CFM turbo......

 

Well it really depends on the situation. What are you trying to do and what are you planning on building. I would see no problem putting a set of 210-215cc. runner heads on a 350 cu.in engine with say a super T-72 ball bearing turbo. It might be a bit lazy before boost, but add a 3500-3700 stall convertor and you will be in boost before you know it. I think the higher flow of bigger cc runner heads will pay off big time in the top end of a turbo motor, especially a bigger turbo, like a T-66 and up

 

I'm building a 383 turbo...... I thought I'd made up my mind on a GT76Q but I came across a PTE88 that I couldn't pass up (new/and price was right)..... So, now I'm trying to figure out how to make this work on the street by getting the turbo spool somewhere short of 4500....... I figure that if I can get more air through the heads I'd be able to spool quicker..... That and mess with my turbine AR and wheel size....

 

A turbo is like a pair of shoes. A nice looking pair of shoes on sale, doesn't mean they will fit your feet (correctly). Is that how you buy your shoes, by price, or by how they fit your feet? You can make those oversize shoes fit (better) with more socks, but it won't compete with the pair that fit your feet correctly. Not a good idea to fit your feet around the shoes, as compared to fitting the shoe around your foot size (and shape). Make any sense? Buy what you need, not what your eyes want.

 

Arnie- Nice analogy..... I understand what you're saying.... I am thinking the same way, but literally, this turbo was almost given to me..... If I can make it work - great - if not I'm sure I can sell it for more than I paid.... I am just getting creative and am asking headflow/port volume questions to see if I can validate my own assumptions.....

Ultimately, I think it would be great if I could figure out a way to make this work..... I think some serious heads combined with the airflow of the T88, would make a good low boost pump gas motor.....

What I'm wondering though is if boost can make up for a lazy low rpm head and if the T88 is the right turbo to do that..... Like I said, I'm looking at turbine AR and wheel trim as well as head flow, port volume and cam specs.....

Thanks for the response.

 

I don't know a lot about turbos, but I think the answer to your question is "no". Concerns about low rpm performance would only be relevant at light load/part throttle. Under these conditions, you won't see boost and the heads will work no differently than on an NA application, AFAIK. I mean, you don't normally run WOT at 2,000rpm anyway, right?

Rich Krause