Re: The Colorado BS thread
My dilemma is to either spend $700 upgrading my compressor wheel, turbine housing, and tossing a rebuild at my stock turbo or spend $1500 on a drop in GTP38R ball bearing turbo that is brand new and should spool just as fast while being more durable and capable of supporting further mods in the future. Truthfully I don't intend to upgrade my injectors or HPOP, but I also know myself well enough to know that if I ever need to replace either I'll probably upgrade them.
There isn't anything mechanically wrong with my stock turbo, but being chipped (I only run a +50hp tune) I get boost surge when towing and I want to drop my EGT's when pulling hills. On I-25 its not an issue, I can set the cruise at 80mph in O/D and just cruise along with minimal surge and EGT's plenty happy. When pulling mountain passes though I'm having to drop a gear and slow down to keep the rpm's up so that my turbo isn't surging and my EGT's stay happy. For example, pulling 285 up to Conifer I have to run 2nd gear at 50mph and 2200 rpm or so. Doing this EGT's hold steady at 1000deg pre-turbo and I get no surging. If I stay in 3rd gear my turbo will surge pretty bad under load and my EGT's will hit 1400deg, which is way too high. I'm ok tapping 1300deg intermittently but really anything over 1250deg is bad.
The factory Garret turbo is a journal bearing turbo with an 80mm wheel and 0.84 A/R turbine housing. I swap the compressor wheel out for $200 or less to get rid of surging, and replace my housing with a 1.0 A/R for another $400 to drop EGT's by a good 150-200 degrees. A rebuild kit is another $100 or so. I'll get a bit more turbo lag with the 1.0 A/R housing but the wheel is supposed to also help offset that along with getting rid of surge.
The GTP38R turbo is a ball bearing turbo with an 88mm wheel and 1.0 A/R turbine housing. From what I've been reading despite the bigger compressor wheel it spools up just as fast or faster as a stock turbo with a 1.0 AR housing. It'll also support more fueling/power if I were to ever go that route.