I'm wondering what kind of vacuum your engine pulls at idle. Mine seems to be on the low side at 14"hg. And the engine idles very rough and choppy. Can you guys post your vacuum numbers if you have them?


Thanks,

 

What RPM are you measuring that at? Or more importantly, is this with a stock chip. If you're using a stock chip, the idle speed is going to be way low, like 550, maybe 600rpms. And i can believe 14" at that low of an RPM for that cam.

 

Mine used to be 18" at 750 rpm.

 

Did you double check all the lines and use new gaskets all around when you put the heads back on? I always use new gaskets when the runners come off.

Your car idled a little choppy waaaay back when I first drove it. Sounds pretty good!

 

The chip is not stock, I transplanted a T56 into the car, and it idles between 700 & 800. Formul8, I did use all new gaskets. The engine has always pulled low vacuum ever since I put in the cam. I'm just getting fed up with it so I posted this question here. It sounds like 89gta383 had good luck with the cam and that's what I think the vacuum should be at.

 

Make sure you don't have any vaccum leaks. Your compression will affect vacuum also, I had 10.8:1.

 

That cam is made to idle at 900 if I remember right. I have it in my car and it is very smooth at 900 but I have bumped it to 950 for the heck of it. Unfortunately I don't have any vacuum #s for you.

Did you install it straight up?

 

Yep, I did install it straight up. If you could get a vacuum number that would be great. I'm assuming your vacuum would be around 19 because of how good you say it's idleing.

 

You should retard the cam at least 1 to 1.5 degrees for a LTR setup with that cam. This what I have been told by many sources.

 

The 219 itself has 4* of advance ground into it.

 

Ray Bohacz (old GMHTP tech editor) always use to recommend that the "211" and "219" be installed 1 to 1.5 retarded. I have no idea if it pays off or not.

 

Almost forgot.......

I have the "219" in my GTA with around 10.8:1 compression. With my old chip it idled at around 900 and was pretty smooth. With my current chip it idles at around 700. Or more like it doesn't idle. Sorry, I don't have any Hg numbers

 

What do you mean by this?? Now it doesn't idle at 700?

 

It will barely idle at 700rpm but my PROM is far from optimised.

 

Are you burning your own??

 

I started with an Ed Wright masterpiece. It was ****. I'd been using a chip since then that a friend made up until the I took the car off the road for winter. It made the car quicker but drivibilty was terrible.

 

So is your buddy just an average "joe" burning his own chips? Do you use any kind of scan tool to see what the engine is doing? How many chips has your buddy burned?

Just curious