Topic: upgrade turbo or bigger turbo

[captain]

I am trying to decide on weather to get the big wheel upgrade for the stock turbo or get a bigger one.I like to drive twisties and so I do not want a big lag time my car has an auto tranny ,but I want the increased hp to the rw and torque.Would like to hear from any who has done either

[DeepBlueGXP]

First, do you have any mods to your GXP?  what year is it.  GM has pretty much eliminated the lag with our setup, if you increase the turbo size, you will have more lag.  Also, BTF has seen a lot of the stock turbos needing refurbished so the initial cost will require an additional 200-400 bucks for repairs.  IF you don't have a tune or the gm stage II, I recommend you get the stage II and the westers tune for it. 

Chuckdoc will be testing a Westers tune for the Stage II in a few days.

[lil goat]

There is no such thing as a Stage II for the GXP, it is a GMPP tune from GM Performance Products. There is a lot than can be done with the stock turbo like Joe said, I think the GMPP tune with the 3 BAR TMAP upgrade PLUS the Wester's tune for the GMPP sensors will be the ticket.

[captain]

I have a solo mach and free flow cat from solo amd a gm cai,I am thinking of the big wheel upgrade for the turbo the gm stage 11 and a good tune from one of our tuners

[jonymac]

Captain - I am considering the same question.  I have a manual Sky RL with RPI exhaust, RPI intercooler, intercooler piping, CAI, bored out TB, Dejon elbow, Wester's tune and a high speed, low drag painted engine cover.  I am thinking of getting the RPI catless DP, but if I change my turbo out I may need to get a new DP or do some cutting and welding...

I use my car as a DD and 1/2 my commute is relatively traffic free twisties, hills and small straights with some start and stops.  The other half is sitting in bumper to bumper traffic on 395 north to DC. .  I really enjoy a very quick and powerful car, but rarely will be taking it over 100mph.  I love responsiveness and a quick spooling turbo, but am still searching for more low and mid range HP.  (My first car was a 66 Mustang with a Boss 302 that pulled like mad on the low end.)

Anyway I am thinking of three options:

1. Big wheel turbo upgrade from PerformanceWerks or BTF - can use the catless RPI DP bolts right up - no problem - same spool up time - not much more HP for the money

2. Mitsu 16g turbo replacement from Dejon - not sure yet how this would mate to the RPI DP - research needed - slower to spool up than our Borg Warner

3. Garrett 5457B turbo replacement from Dejon or GT3076R from BTF - custom DP included - some clamp work to mate to the RPI exhaust - BIG time torque and HP - much slower to spool up tho

I would love to hear other's opinions and ideas - and anything else I should think of.  I am also considering doing the gmpp upgrade for the sensors and then reflashing my tune from Lyndon once he has figured out all the gooey goodness he can get from the 3bar sensors and increased boost.

[LatinVenom]

All I can tell you with the Larger wheel turbo and a tune the car responds very quickly and to 23 psi.

[jonymac]

Bump - any other input?

[DirtyMike]

i am very happy with my larger wheel in my turbo, comes in harder with more power and oh what fun... and can hear the turbo much more as well.. add ing the shabby pipes with a tial q hopefully this week so i and every one else can hear the turbo too