turbochad - why would a 17c spool more quickly than a big 16g? they share the same turbine housing, turbine wheel, and compressor housing. the only thing different about them is the compressor wheel. if i remember correctly, the 17c comp. wheel inducer is a tad larger than the big 16g's. more mass on the comp. wheel generally means slower spool.

 

Correct on a few accounts. The housings are all the same, but the compressor wheel is shaped differently as well as being a little bit bigger. There are a few trade-offs using the 17C. One is efficiency. Below 20psi the 17C is more efficient then the G series because of the shape of the wheel. Because of this efficiency the turbo will spool faster. The downside is about 20psi that efficiency drops off dramatically. What this boils down too is that under most pump gas conditions the 17C is better, but under high boost/race gas conditions, the G series are better. It's a mute point for me since I never put race gas in the car. I will be able to cheat a little more when I build my water injection setup. Plus the addition of the front mount intercooler made a big difference.

 

can you point me towards a compressor map for a 17c wheel? i've found all the g wheels but haven't come across a 17 or 19c map.

thanks,
marshall

 

efficiency is too broad a term.. if that's the way it was told to you, it was probably meant as it's power efficiency is at a lower PSI than the other turbos that are efficient way past 20PSI

doesn't necessarily mean faster spool.

 

ill ride along and tune, im a little late in the thread but oh well.

I use 550's and they do what i need them to do,but i definalty cant do much more with them. I vote the hrc injecotrs, perfect for the big 16g.

 

625? good choice IMO.. but if you want that much.. why not go ahead for the 650s?

 

isnt around 650's and up when you start getting bad idle and low speed. Correct me if im wrong here, and yes i know it can be tunned for better

 

Fook it, 750s are the shiznit. -Ian

 

well this is an old thread now, but i went with FIC 650s, and i still need someone to ride along and tune with me

 

fic??