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View Full Version : 99 Silverado 4.8 turbo questions



W.P._Turbocars
11-29-2007, 03:33 PM
Friend has a 4.8 chev and is needing to turbo it. I have searched the net with no luck, except for places to buy a "kit". They don't give a very good description though of the parts that come with it such as injector size, fuel management, etc. (Probably so people will buy their kit, rather than go out and build their own.) Has anyone on here done this or looked into it?

Thank you
Gary

zin
11-29-2007, 05:00 PM
When we were designing nitrous kits for these engines we found two important things, one: the fuel pump wasn't really up to the task, and 2: the engine's ECU was "smart" enough to add the fuel needed when the nitrous was injected into the air intake before the mass air meter (limited to about 50-75HP before the fuel ran out). So... I would be inclined to install the turbo and a good fuel pump, then run it at low boost with a wide-band to be sure it's not too lean. Depending on the year, it may still have a fuel regulator under the hood, what that means is that if the computer can't keep up (injectors max'd), you could add a FMU/rising rate regulator to feed the added fuel needed. One thing you'll need to address is the MAP sensor. It'll freak out if you start feeding it boost, so you'll need a zener diode to keep the computer happy. I know those engines really came to life with a little nitrous, I imagine some boost will help it get with the program, while not as dramatic as the nitrous, at least you won't have to fill a bottle! BTW, what size turbo(s) will you guys be using?

Mike

W.P._Turbocars
11-30-2007, 03:01 AM
Looking into getting a like-year diesel and pulling the turbo, IC, piping etc. and using most of it. :)

zin
11-30-2007, 06:51 PM
That should be more than capable of taking care of a 4.8L gas engine! Be sure to start with low boost and slowly up it. Not sure how much they'll take, but I would think that it would be ok with 75-100HP extra. But I'm no expert on how much they'll take in stock form so be careful and have fun!

Mike