turbo questions

[robertisaar]

So you are saying, having a nice lumpy idling cam and turbo counter acts each other?

I know this is dumb, but I was thinking about changing cam, but just because I wanted and like the sound if a lumpy idle.

a healthy N/A cam is usually a horrible choice for a turbo build...

if you want a nice exhaust note, you'll just need to play with the exhuast components. my lowly little dead stock 3100 is mistaken for a V8 due to the exhaust note...

[Joseph Upson]

Make sure you review exactly what you want the engine to do and make your decision based on that. It just isn't necessary to replace the cam to reach a power level that doesn't require it with the use of a turbo. Speaking from experience, if you like solid acceleration for short bursts and an occasional interstate jaunt, stick with the stock cam and optimize everything else, port and polish, good exhaust, higher compression ratio if your boost level permits it. Those three upgrades will do far more than a cam change and will actually improve your bottom and top end where an HO cam will take from the bottom and give to the top. The lope might be nice but if it doesn't deliver the driving performance you expect it will get old fast. No sense in chop, chop, chopping tenths off your 0-60 time if that's the kind of driver you are.

[Weatheralls Auto]

Thanx for the info, I will crunch through some numbers, Bottom end is definitely what I am after, was only thinking Cam at first because I really like the sound of a lumpy idle (I know its trivial, but if it doesnt hurt my lower end, I just enjoy hearing it lol)

[RedZMonte]

I would say get a name brand turbo 1st off.. Garrett, Percision, Turbonetics, ect... I would even run a standard bearing turbo over a generic BB turbo...

Im running my stock manifolds without problems, they are reliable (no cracking) and compact.. unless your builing a racecar its perfect for the street... When i started my build i was told one key thing that has stuck with me... "Keep it simple stupid!!" Get the basic setup in and running berfore you start dealing with cam, porting, ect... im making ~100 wheel hp over stock and have been beating on it everyday without any problems....

One thing i might do is redesign my x-over/DP and do a twin scroll housing and mandrel downpipe.. not needed but will help my spoolup. Im running a non ball bearing T4, 2.25" x-over and 2.5" crush bent dp so i need a little help with spooling...

[carbon]

When calculating airflow for maps plotting... what VE% do you knowledgeable fellers use for a 3400 or 3500? The often suggested 2 valve 85% just seems a bit low to me...

[robertisaar]

stock 3400 and stock 3500...

not calling these perfect, but they are what i use.