Hey,

With the Crane 16s, at low RPM my brakes do not work too well.

What I was wondering if a one way check valve would help to build vacuum.

So if I started the car, revved it up, then drove slowly I would (maybe) have the vacuum needed.

Other option is a brake vacuum pump. Like this:

http://www.summitracing.com/parts/SSB-28146/

Put a check valve between the manifold and the brake booster.

Originally posted by DarkOne
Put a check valve between the manifold and the brake booster.

Will do. Gracias.

this is my problem too. if it works timmay, show me the ways of the force

Originally posted by 420agreenvilleSC
this is my problem too. if it works timmay, show me the ways of the force

My car is supposed to have low vacuum...

Originally posted by teklein

Originally posted by 420agreenvilleSC this is my problem too. if it works timmay, show me the ways of the force

He is too old... yes... too old to begin the training

I am ready! just tell me if it works timmay. stop exposing my unfixable low vac issue

Check valve wont work very well. Antiques battle this all the time with high duration cams. Vacuum pump/cqanister has been the only way to work 100%.

Now if your referring to Crower 2's which are small in terms of duration then you can use a simple canister to remedy the issue.

Originally posted by Star Turbo Talon
Check valve wont work very well. Antiques battle this all the time with high duration cams. Vacuum pump/cqanister has been the only way to work 100%. Now if your referring to Crower 2's which are small in terms of duration then you can use a simple canister to remedy the issue.

Crane 16s now, soon to be 18s.

What is the advertised and .050 duration?

looking at Crane recondations, you going to have a lot of low end problems. Those cams require a 12.0 Compression ratio which means the overlap is enough that the static ratio is dropped a great deal. Static ratio is the compression ratio you are left with after the overlap is factored in.

Without knowing the exact duration at .001 I cant tell you what kind of IDLE ratio your going to have if you still want to attempt running the 10.5:1 shortblock

If brakes are your concern right now then start hunting for a Vacuum pump setup or convert to manual brakes.


Edit: found one listing that claims they have a duration of ADVERTISED 258 degrees. That is very close to the Crower 3 cams and you will prolly get away without any type of canister or check valve if you tune it right. Your Crane 16's are an Advertised duration of 250 degrees. The 8 degrees wont be noticable Tune the idle to the vacuum like your supposed to and it will be fine. For what they consider a "drag" cam, that duration isnt that big. Street cams are usually no more than 280 degrees of duration. Even the 4g63 street cams run a duration of 272 degrees. Factory 420A cams are 222 degrees; thats only 30 degrees more.

I dont see how they can claim a 12.0: ratio is required. As long as you have 9.5:1 your fine

Your poor vacuum now is becuase your not tuned to the cams. The maps are tuned to the factory profile. Once you tune the idle fuel and idle timing you should be at least 10" of0 vacuum at 800RPM. If you raise your idle to 1000 then you should be able to get 12-15" out of them.

I'm not sure what he is pulling now at idle but its a pretty steady idle of 1000-1100 and seems to stay smooth. I will have to give a report back after I talk to Tim and tell exactly what the idle vac is...

Watched the MAP this morning Terry and Zac.

Im getting 45-52 KPa at idle, which should be ~13in.Hg.

Ive noticed that the brakes are GREAT, so looks like problem solved.

Stock ECU they were horrible, when stopping you could feel the brakes get worse as the car idled down.

And yeah, the car idles at 1050-1100. It doesnt like anything lower, but its rock solid, so I cant complain :)