ol Dusty

iTrader: (2)

I have recently started collecting turbo parts and once apon a time I built a N/A motor and it came up that the cam would be useless to me if I ever went turbo, kinda like high comp pistons vs turbo pistons.

However, reading up on turbo d's I read up on a 505 hp build with a cam described as being very similar to a crower st2 N/A cam. Then having posted my crower N/A cam the first reply so far was from someone wondering if it would work for a turbo set up? anyone able to help dumb this down for me a bit?

bbarbulo

iTrader: (2)

it all depends, what you don't want is a lot of overlap in the cam since then the boost is being bled off. but the higher lift would help the cylinder fill more efficiently. you're best to try it, dyno it, then try a stock cam. it's the only way to really know for sure.

ol Dusty

iTrader: (2)

sounds a little expensive for finding out for someone else.

zeeman

iTrader: (1)

well, unfortunately thats what you're gunna have to do. Theory only goes so far, the only way to really know for sure is to put it on the dyno to see.

weir

they make n/a cams and turbo cams for a reason. i'd imagine they don't typically work as well in an application they weren't designed for. seems pretty cut and dried to me.

T-MacK

The only cam I have used on both Turbo and N/A set-ups is the Zex 59300.
Awesome cam for Sohc's.

driven905

^^ http://d-series.org/forums/printthre...t=16102&pp=100

" Zex 59300 cam dynoed.. not so good ! "

T-MacK

Did you read how his set-up is completely stock on a y8 except for an exhaust??
What do you expect?
I'm making 155whp on a d15b with my Zex set-up.

stealth512

I'm going to try to take a crack at dumbing this down. I've spent a lot of time trying to figure out this very same thing and the best information I got came from the evans-tuning forum.

Basically the more efficient/better designed your exhaust manifold (ie not a log manifold) and turbo is the bigger a cam you can put in a see gains; up to some point of course then you will see diminishing returns.

So that's why back in the day they said N/A cams were bad, because everyone had log manifolds so the big cams didn't help.

stillslow

I know with a B series the skunk 2 Pro1 cams have made some real nice numbers in boosted car.From what I have been told after 400whp the pro 1s make more then the turbo stage 2 cams.

zeeman

iTrader: (1)

alot of it is based on the turbo setup. Don't expect big cams to work well if you're using a log manifold and small exhaust. Buddy Club 3's are their mildest cam, so I could see them working decent on a boosted setup.
If you use a nice equal length (ram horn) manifold and have a free flowing 3" exhaust i'm sure the bigger cams will work well. I mean if the valves are open higher and for a longer amount of time (duration) then in theory why wouldn't the engine benefit from the bigger cams when boosted?
The problem is when there is too much overlap (from aftermarket cams) and how the incoming intake charge (or boost charge) can potentially just blow right through the combustion chamber and out the open exhaust valve. At the same time, the reason why bigger cams don't work so well with a log or cast iron manifold and restrictive exhaust is b/c the exhaust gases can't exit the engine fast enough (due to the restrictive manifold/exhaust) so what happens is that the spent exhaust gases get sucked back in through the open exhaust valve (b/c of the amount of overlap) thus contaminating the mixture in the combustion chamber resulting in an incomplete burn of the air/fuel mixture which translates to LESS power.
So there is definately a fine line between what will work well and what will work against you. I have firsthand experience with this with my car.
I was using crane stage 2 cams on my boosted b16. Since i've got a crappy manifold that was made by splitfire and a 2.5" exhaust the bigger cams were working againt me. When vtec would engage the power would dip down a good 20whp or so, the dip would be not so dramatic with the vtec crossover set at a higher RPM. This is b/c more overlap is high RPM friendly, not so much at lower RPMs....on a small(er) displacemenet engine at least. So in an attempt to dial out some of the overlap I adjusted the cam gears apropriately, resulting in a smoother vtec crossover even at lower RPMs (under 6000rpms) but the power dropped across the board, especially at higher RPMs. So I've since switched back to the stock b16 cams and now have a nice smooth vtec engagement (at 5500rpms) and good power throughout the powerband.
So don't think a tune and some cam gear adjustments can/will fix cams that are too big for the engine/setup....b/c it won't.

FPMotorsports

^^^ First off listen to this man.

2ndly The Zex Cam makes Jam!!!
I ran 13.2 1/4 mile on a 75shot, slicks, zex cam 59-300 etc....

Most I made all motor was 160whp....
p&p head Full race p&p valvetrain etc, Custom Built JG Engine dynamics manifold, head gasket mod, custom lightspeed / JG engine dynamics header, aem 3" cai, 2.5" exh. custom JG tb, fpr & gauge, msd 6a, Zex Cam 59-300, NRG ground wire kit, NRG ground stabilizer/ booster, walbro 255 pump, No cat/res., 8lbs flywheel, custom JG Engine Dynamics Crank Pulley No alt no power steering and the list goes on. Basicly a freshly built oem stock D15bvtec bottom end and a z6 full race head.
Anyways I made 140whp with a lot less mods and the Zex cam in.
It's the best D series Cam hands down I don't care what any1 says.
I boosted a stock D15bvtec to 251whp and 202wtq @ 10psi, slapped it in a built D series etc etc and just sold it last summer it still looked MINT.

3rd : Skunk2 Tuner I cams make power on boosted set-ups and so do the Pro Stage I's.
I've seen this first hand and you can check out Jeff evans website.
I wouldn't be running them if they wouldnt make power for boost on a b series