Question on a custom cam grind (3.8 turbo, not a GN)

[caindo]

Howdy,
Im currently rebuilding my 97 pontiac grand prix GTP motor (3.8 s/c) and am converting it to a i/c turbo setup (pt60-1 with air2air i/c). I've also had the heads fully p&p`d with oversize valves. the block has new diamond forged 8:1 pistons and forged rods. Our stock gearing for these 4spd autos is 2.93 and i do wish to stay with that for mpg purposes (that and turbo cars dont really need gears, just bigger stalls) and for that i have a tcc300 which is about a 3500 stall depending on the weight of the car obviously. Stock 3800 camshaft lobe lifts are .258", giving theoretical stock valve lifts of .413" with our stock 1.60 rockers. my heads can clear over .650" of total lift. my question is, with my mods to my heads and still wanting this car to be streetable, what cam grind should i go with? i dont mind if it has a small lope to it as my last s/c motor had a pretty gnarley cam in it. but to my understanding turbo cams dont need the lift, just the overlap. any and all help is appreciated since im new to this turbo stuff. looking forward to kicking my s/c`d gtp counter-parts' asses.

Regards,
Jon Cain

PS: the cam grind i was told would work great is 211/211 520/520 111 LS. keep in mind im going for around 500whp or more. thanks alot guys and gals.

 

[TurboTR]

Yes, that would probably work great. It is still a pretty tiny cam however in the grand scheme of things. Should be very mild. With turbo backpressure, overlap is probably something to avoid as much as reasonably possible. And with the amount of air you'll be moving, lift (or better put, flow capability) is probably something to seek

TurboTR

 

[jbunla]

There is absolutely nothing wrong with the stock cam!
You have ported the heads and understandably will like to go with something that will compliment it, but the stock cam will take you there with a turbo. turn the wick up lol, let the heads to the work. Do you want more rpms than the 6K?
To get the cam right, you will have to know more or less about the turbo you are planning to use!!

 

[caindo]

i put in my first post that it would be a PT 60-1. my stock cam was really designed for s/c but works "good" with turbos. im just looking for a little "extra" while i have the moter down.

 

[nocutt]

Caindo,
I also vote for keeping the stock cam. The problem is NO ONE has designed a real turbo cam for the 3800S2's. To design a 'turbo cam' take more than quoting specs. You can get by I am very sure, but in order to optimize you will have to know literally when you reach crossover with that turbo or rather your particular configuration Literally you will do better with a bad turbo (as in undersize) with a good cam (stock cam) compared with a bad cam with a good turbo . I honestly think you should maximize what the stock cam will do before attempting a 'turbo cam'...but that is just me. The SC cam is no different from a stock NA on the 3800s. btw that is a good turbo...make sure you get some nice head bolts...good luck!!