2.7 CIS guys please chime in...

thrown_hammer · 10-16-2002, 06:52 AM

I think I have solved my sputtering problem. What I need to know is this... The car pulls strong from 3000 to 5000ish RPM. From there to redline is doesn't seem as urgent but still pulls to redline with no hesitation in 1st and 2nd gear.(3rd is a bit risky on the way to and from work)
What RPM does the HP/Tourqe peak? Is this the typical power curve for a stock 2.7 CIS car?

Targa77 · Targa77's Garage

I hope this helps:

http://www.middleyear911.com/techspecs.html

thrown_hammer · 10-16-2002, 07:54 AM

So with this data would that explain that the rush of acceleration drops off a bit after 5000 RPM since the torque peaks at 4000RPM?

1975 2.7 911S USA 49-state 8.5:1 2687 cc, 165HP @ 5800 RPM, 167 lb/ft @ 4000 RPM

Targa77 · Targa77's Garage

Assuming that this data is accurate, yes. Remember, torque gets you going from a start, but HP is what makes you faster after you're going. Of course, timing will affect both of these (timing that's too advanced will decrease torque but increase HP). There is really no need to wind your car to redline to achieve peak HP since you've already maxed out these around 5800 RPM.

thrown_hammer · 10-16-2002, 10:37 AM

I am going to assume your car is a 1977 targa.

Does your car drop off on acceleration after 5000RPM? Mine still acellerates but not with the urgency that it did from 3000-5000RPM.

michigan · 10-20-2002, 04:03 AM

I am pleased to tell you that my 1977 cis, 2.7 L continues to pull steady into the redline/rev limiter range. I have 74,00 miles on it. The timing is at 3 deg. atdc, the dwell angle 41 degrees with points set accordingly (I forget now).The cis is on the rich side. My problem is in the lower gears getting up to max too quickly and not floating the valves. As you might guess, I love my car. I have also taken pains to be sure that I do not have any vacuum leaks in the system. I am presently thinking about purchasing new injectors just to be sure that she stays right.

Adam · Adam's Garage

I had similar problems until I had new injectors fitted to my '76.

It pulls very cleanly up to the redline, but I think after 6k rpm, it's making more noise than power.

marcesq · marcesq's Garage

Thrown:

The 2.7 engine should spool up from 4k to redline until it hits the rev limiter.

What heat exchangers do you have?? and what are your timing and point settings??

How old are the spark plugs, wires, distrib cap and rotor??