.81 A/R exhaust housing

[Tannhauser]

I've seen a Sound Performance spgt800W turbo for sale (with a modified d.e. kit). It's nearly new and the vendor is advertising it as having 'minimal lag'. However, the exhaust housing is .81 a/r, which I understood would tend to give lots of top end but with attendant l-a-g. This is not what I'm after at all.

 

However, I'm aware that turbo design keeps moving on, so I'm wondering if there is any possibility that developments have reduced the adverse effects of such a large a/r?

 

Also, I wasn't sure if the compressor and exhaust sides could have different a/rs and if so, which tended to be cited as a turbos a/r figure. I had been thinking along the lines of .58 for fast spool, but I don't know now whether this applies to the compressor side, the exhaust side, or both.

 

It may also be that these questions make no sense due to some large gap in my understanding.

 

Any ideas?

 

Thanks,

 

Cliff

[Guest Terry S]

Waht size is the compressor wheel?

 

0.58 would need a relative samll comp wheel if it was not to surge. 0.68 seems about right on a reasonable sized turbo. You really need someone who knows the turbo's to match the AR. I have already had a problem with one.

[Tannhauser]

OK thanks Terry, I'll enquire if it hasn't sold.....

[Adam W]

I would say .58 for a 63mm wheel or smaller, .68 from 63mm to 71mm, bigger still after that. Just from what Ive said you understand. .68 is a good starting point I reckon, I'm actually thinking of stepping up to .81 on mine.