I got my truck with about 100k mi, now has 170k. Since day one it has had a terrible turbo lag off idle. If from a stop and I floor it, it takes a bit more than 3 seconds to get above 10PSI, then it feels like the AFC says ok, have some fuel, and it pulls hard after that (22-24psi with wastegate, 34 peak without). Whoever had the truck before me played with the starwheel, all the way out, and the plate was full forward, stock profile. So I backed the wheel in to about 3/4, and ground the plate to something like a 100 I think (flat down with a hook at the bottom).

Regardless of starwheel setting, lag is about the same, maybe a little less with it all the way out but lots of smoke off the line. Smoke is noticeable at full boost, but not clouding out traffic/etc. Since I have NO idea what else the previous owner did, does anyone have any numbers off the stock 12ccm turbine housing versus the 14 and 16 ccm models? It is wastegated, but I've driven other stock 160 and 180hp models and they didn't have lag this bad. Unfortunately I don't have EGT gauge yet, just boost and trans temp.

Any thoughts? I've wanted to get a 14 or 16 wastegated turbine housing if possible before I add any more power, as it seems to run tight on the highway. Its a 98 12v auto cali. model (180 hp, 14* timing stock).

Any help and/or part #'s for 14 and 16ccm housings are greatly appreciated! I haven't been able to find a description online for the different p/n's. Thanks again.

 

I would check for boost leaks or cracks in your head. More often than not thats the cause of high egt's, low boost numbers and high drive pressure. Sounds like something is off and its a good way to move forward is to make sure that everything is working the way that it should. How well does the turbo spin when you spin it by hand?

 

Pretty sure no boost leaks are present, I had problems popping off connector hoses at 30+ psi before so I went through the intercooler/pipes/connecters afterwards. Pressure tested system from turbo outlet to connector to intake head and had no leaks at 30 psi at the time.

Now that you mention it, turbo has crossed my mind. When the wife drives it and just shuts it off regardless of my comments it sounds like there is a little rubbing on spool-down, rather than a nice smooth "whoosh" I guess. Anytime I shut down I idle for at least a min and it sounds clean while slowing down. Intercooler pipes were also lined with a nice coat of oil when I got the truck, no prolonged idling has fixed that.

When cold, if I spin the wheel by hand it will seem to spin free for a few revolutions and come to a tight spot and stops. No radial play noticeable by hand, just a hair axial-shaft in and out.

Bad lag...anything to do with this?

 

add a gsk kit and your low end response will be much better assuming no leaks and all is functioning properly. slight play in the turbo will only get worse with usage. may be time to think about an upgrade. a gsk kit is one of the best mods on a 12v. eliminates all bogging which is normal for 12v's without mods.

 

http://dodgeram.org/tech/dsl/FAQ/turbo_faq.htm this site might help u identify the turbo housing sizes plus its got some other info that u might find interesting my buddies 96 has a little play in the shaft more side to side than anything we swapped his 12cm2 for a 14cm2 and wow what a differance it can hold a steady 40psi with no problem really woke up his truck and cooled down the egts untill we put in some ddps last weekend