Any progress on the prototype intake manifold? I'm extremely interested in this subject, I plan on it being my next bolt on, assuming it's what I want. I'm pulling a lot of vaccum at WOT, and I imagine it's that soda straw manifold sitting atop my 3.4 causing it

 

Some, yes.. I've got to get to the metal yard, and get the actual metal to start - but I do have the layout/design complete.

 

This thread is useless with out pictures

 

did you put a vacuum guage on it so that you can watch it while you're driving yet? i'm nearing completion of my new intake manifold. big it shouldn't be too long...

 

yes. And I wasn't surprised.

 

i'm not doubting you but i don't understand how your motor will pull vacuum at WOT when i'm runnig more cam and not pulling vacuum at WOT. not pulling any real significant vacuum anyways.

 

I took a run without the turbo shortly after teh boost/vacuum gauge was hooked up, and at 5600 rpm, I was pulling about 1.5" of vacuum - it got worse as I went higher!

The volumetric efficiency of our engines SUCK at higher rpms - thanks to our free flowing intakes and exhaust manifolds

 

maybe my vacuum guage isn't that good...

 

What vacuum gauge are you running? What type of tubing? i'm using hard plastic line here..

 

I've got a bit more displacement as for the cam, vac will be lower I thought? Maybe I'm thinking at idle...

 

Vacuum drops during WOT. With my cam, vacuum dropped to nothing. That's why I had to get that vacuum reservoir. It's good to have power brakes when you are going fast!

 

Jerriko, that begs the question, why don't you take your foot off the gas before applying your brakes? I have.. well.. negative vacuum at WOT.. no braking problems here

 

I was just referring to if someone pulls out in front of me while I am at WOT. Or a light changes, etc. I just like WORKING power assisted brakes.

 

i don't remember what brand my guage is, i'll look at it later. i'm using some plastic tubing that cam with the guage. i have a "T" inline right after the hose exits the manifold.

as far as vacuum with a bigger cam. yea, at idle it should be lower with a bigger cam. but, if someone (you) has vacuum at WOT, I should have more vacuum since we're running the same intake and all (for now). because, my cam, being bigger, pulls more air. so, if you're pulling vacuum at WOT, i should be pulling more, other than the fact that you have a few more c.i. than me.

 

Unless that tach is inaccurate, and you're not spinning the rpms you think!

 

well, i've had the tach showing over 7k many times before so i would guess that the engine is atleast turning over 6k...

 

Methinks you need a new tach

 

I am still confused by your statement. No engine proceeds vacuum at WOT. What line did you splice the vacuum gauge into? Vacuum is created at idle, not WOT.

 

If you've got a big enough restriction (the TB or the intake) you will read slight vacuum at WOT, as well, as the airflow the engine wants increases past what the TB/Plenum can provide.

 

Can happen. I spliced into the T on the back of the plenum (removed VAC control line, my heater doesn't work anyhow).

 

How much vacuum are we talking about here?

 

About 3"....fluctuating. You can feel it being choked, you never had this problem with your motor Jerriko? Oh yeah, and:
Any news yet Doward? DId ya get your metal yet?

 

No, I don't have any vacuum with my motor at WOT. That would tell me that something is not right.

 

All it means is that between the back of the plenum and the air cleaner/filters, *something* is causing a restriction. 3"?! jeez. Dirty paper filters maybe? One can hope....

 

you can still have vacuum at wot if your intake manifold is bad enough I'm sure

 

Or anything else, for that matter... air cleaner, filters, ductwork, MAF, throttle body...

 

Hoping to get out and get the metal this week.... I finally got enough $ to get the ZT-2 wideband O2 sensor, so the T61 is my first priority.