Trying to spec out the new turbo engine and have been comparing camshaft specifications. From Comp, Cam Motion, Crane, etc, ..... The goal is 1000 HP from a 400 in^3 SBC. Looking at running twin turbos and am trying to sort out the cam specs. One name which I can not find is Duttweiler. Ken Duttweiler has been running turbos for years, but I can not find a web site or phone number. Does anyone have any spec's on Duttweiler cams? It looks like Cam Motion doesn't run alot of duration while Comp and Crane use quite a bit more duration. Curious as to where Duttweiler comes in at.

 

Call him up, tell him your specs and he'll order one right up for ya. Thats what i did

for my hydraulic flat tappet with twin 60s on gale bank manifolds he gave me

232/232 .515/.515 (1.6rr) 114lsa/114ic

told him i didn't want to go higher than 6500rpm

 

Thanks for the information. Do you happen to have any numbers for this combo. Sounds similar to engine speed range that I am shooting for. Any pictures ????

 

it isn't totally together yet....but here it is mocked up. As of right now i'm waiting on new longer rocker studs, pushrods, and my elbow/intake ported

jim

http://home.earthlink.net/~tt3rdgen/...tor5_small.jpg

 

David Vizard ground the following for a turbocharged 350:

200/234
126 LCA, 9 degrees retarded

I know it sounds screwy, but he has a very good explanation of why it works. Also, the motor made 1000 hp at 5000 rpm and over 1100 ft-lb of peak torque on 28 lb of boost. It also idled at 450 rpm glass-smooth, he says.

Mike

 

If indeed those Vizard specs are accurate, (200-234) they would definitely be in conflict with what some very knowledgeable and respected engine tuners/builders known to this forum advise.

89Procharged, what is c.i. of engine referenced in the link?

 

arnie, I agree that they seem unconventional from the normal turbo logic.

Did you know that the stock Turbo Regal cam is ground on a 106 LCA? That is also against most turbo cam logic, but Buick did this to let some fuel blow into the exhaust manifold during overlap to quicker spool the turbo. Once the turbo spooled up, though, this probably hurt power.

My point is that there are many theory's on turbo cams, and the desired results determine which is the best.

Some of the aftermarket Turbo Regal cams are reverse-split duration ie. 210/205. This cam works because the short exhaust timing stops high pressure exhaust gas (as is the case with turbo motors) from getting back into the cylinder. It also achieves it's purposes.

Vizard's cam uses conventional exhaust timing, but the intake lobe is small and retarded quite a bit. His theory is that the piston must begin traveling down the intake stroke before the intake valve opens. If there is 20 psi residual exhaust gas in the chamber at TDC before the intake stroke, it does no good to open the intake valve if you only have 10 psi boost. So, you don't open the intake valve until the piston has travelled down and relieved the residual pressure.

Mike

 

just a lil'o 355

ported track 1 heads

twin 60s

just junk in a turdgen

 

You (89Procharged) had mentioned cam specs that were recommended by Duttweiler for your engine. Could have mentioned it 'above', but anyway, wanted to know what cubes the 232* cam had been recommended for, to get a little better idea on how aggresive his application recommendation was.

 

umm....it says right there:

"just a lil'o 355 "

I told him, actually the girl on the phone, my whole setup. my main points were good idle, strong vacuum, powerband to 6500rpm.

 

Any idea how much duration could be cut down considering steeper ramps with a hydraulic roller and a 6000 RPM max opposed to 6500? How much was the cam?

Duttweiler will be getting a call from me Monday

 

I just recently read that same book from vizard.
Copyright 92'
Cam specs for turbos are highly dependent on the pressure measurements after the build is finished and running. A/R ratios, cubic inches, head flow, exhaust restrictions................... Even then, the cam can change the pressure in the intake and exhaust.

His cam advise was very interesting and different.

 

you'd have to ask him on the duration....$160 shipped. Remember it was a flat tappet not a roller