You probably won't need any bigger than a .84 on the to4e, now if you had a 60-1, to4s, to4r, 62-1 etc you'd want the a/r 1.0 housing because those turbo's will make more top end power and you have to get the exaust out faster.. The .84 is a good match for the turbo you have, especially if your running a stock or mild side port...

 

I would be more worried about the DP and turbo not having fitment issues inside the engine bay when you switch to a 1.0

 

changing from a a/r .84 to a 1.0 won't affect the fitment of the down pipe... It will fit exactly the same.. you just need to make sure you get a 1.0 housing that has the same type of flange that your current turbo has..

 

Exactly, and HKS uses brackets off of the turbine housing to hold the DP in place with two bolts, it is sealed with two metal rings on the end of the DP. I haven't checked into what Garrett offers in their housings, hopefully everything isn't V-band.

 

that's the slip joint type, there is also a V-band and 4 bolt flange type as well...

 

the t04e kit i saw was 4 bolt dp



mike

 

I would go with a larger housing.



I think the 57 trim TO4E is highly under rated. From compressor maps it looks like it is a damn good turbo for a stock/extend ported 13B running 15psi like your average Joe does. In fact it looks better than a 60 trim TO4E, 60-1 or 62-1. I can't see any reason why it shouldn't make at least as much power as any of those turbos.



From most examples I have seen this does not appear to be the case. However all of the 57 trim cars I have seen were running small exhaust housings. I believe that the power differences seen between the turbos have more to do with the exhaust housing.



It all depend how much lag your prepared to trade for power, but I think 1.0 (divided), 0.96 (undivided), or 1.15 (divided) would all show worthwhile gains.



By the way I don't have a 57 trim TO4E, I have a 60-1 with P Trim and 0.96. However I'm considering buying the 57 compressor wheel, housing and backplate to give it a try. Its only $300 which is pretty chaep as far as turbo stuff goes.