250 bhp from CIS ?

davidbir · 07-02-2008, 03:16 PM

Hi all, is it beyond the bounds of possibility to get 250 bhp from my 82 SC 3.0 using CIS? I have heard the an SSI exhaust and 964 cams will give "up to 50 bhp improvement". It is in normal N.American trim at the moment.

widgeon13 · 07-02-2008, 03:20 PM

I have done it and I believe the realistic figure is more like 20+, at the most 30 HP. It's still a nice boost for an SC in lightweight trim.

Superman · 07-02-2008, 03:29 PM

Not a chance.

But I do strongly recommend the improvements you mentioned. They will improve performance. I'm not even sure the cams will raise horsepower, but they will make your car more fun to drive. More torque under 4000 rpm. A 30-hp gain is unlikely. Like Widgeon said, perhaps around 20. But again, those two improvements will make a difference you will notice and appreciate. The engine just "likes" the SSI's better than the stock heat exchangers.

RWebb · RWebb's Garage

sure you can -- with a turbo...

Trotskyite · 07-02-2008, 03:37 PM

Quote:

Originally Posted by RWebb

sure you can -- with a turbo...

Hell you could get 500... for a few glorious seconds.

bell911 · 07-02-2008, 03:42 PM

Just for fun, if one were to ditch the CIS for carbs, would the Hp jump that dramatically in the nearly stock configuration decribed above?

rs6er · rs6er's Garage

Nitrous anyone?

RWebb · RWebb's Garage

No, but the fun would jump significantly if not dramatically

Rusty Heap · Rusty Heap's Garage

See my sig. Superman is right, more fun and pulls hard from 4-6K with web 20/21 cams and SSIs, but nope, nowhere near even breaking 200 h.p on a dyno. 180-185 dyno h.p max on a good day.

Facts and data over-rule rumours and opinions anyday.

Jeff Higgins · 07-02-2008, 05:12 PM

The '82 3.0 is a "small port" motor, and is limited as far as the peak power it will achieve with these changes. I've seen a fresh '83 with 20/21's, SSI's, and a Monty muffler pull 173 rwhp or so on the dyno. My son's '79 SC with SSI's, a Dansk single out sport muffler, and stock cams ran 180 rwhp on the same dyno. The difference between the early large port 3.0 and the later small port 3.0.

The biggest power improvement on the 3.0 (of either port size) is to simply get rid of the CIS and replace it with carburetors. Add that to the mix, and you can count on another 10-15 hp on top of the 10-15 you will get with the cams and exhaust. The whole package - cams, exhaust, and carbs - might be worth 30 hp over stock. A very noticeable improvement at that. You will, however, lose significant gas milage over the CIS. That might get increasingly important.

fred cook · fred cook's Garage

Has anyone tried a Nitrous setup on a 3.0 w/CIS? That should make some interesting numbers!

deathpunk dan · 07-02-2008, 06:34 PM

What does a ROW SC or Carrera 3.0 engine typically dyno vs a US spec one? Just curious.
Also, how does a 3.0 with 964 cams/SSIs compare to a chipped 3.2 with SSIs?

Sorry, just curious. I'm sure these are all #s 50%+ higher than what my car would make...

davidbir · 07-02-2008, 06:54 PM

Quote:

Originally Posted by deathpunk dan

What does a ROW SC or Carrera 3.0 engine typically dyno vs a US spec one? Just curious.
Also, how does a 3.0 with 964 cams/SSIs compare to a chipped 3.2 with SSIs?

Sorry, just curious. I'm sure these are all #s 50%+ higher than what my car would make...

I think those are really good questions and along the line of what I was asking.....

Gary.H · 12:06 AM

Quote:

Originally Posted by Superman

Not a chance.

But I do strongly recommend the improvements you mentioned. They will improve performance. I'm not even sure the cams will raise horsepower, but they will make your car more fun to drive. More torque under 4000 rpm. A 30-hp gain is unlikely. Like Widgeon said, perhaps around 20. But again, those two improvements will make a difference you will notice and appreciate. The engine just "likes" the SSI's better than the stock heat exchangers.

Dyno results after my 3.0 Euro '82 SC top-end rebuild. 964 cams, race springs, TI retainers, SSIs, stock 9.8:1 cr:

Dyno plot before rebuild, stock apart from SSIs:

Lost some mid-range torque, peak power now higher up the rev range (due to not increasing the cr I suspect). Much more top end power.

beepbeep · 07-03-2008, 12:52 AM

Yes, but far from worth it.

230hp 3.0 with CIS is almost in "not worth it" class. Price/performance starts increasing exponentially after 230...

Arguably, you could fit 930 CIS and get it to breathe more freely, then use very radical cams but intake pulses would kill the idle and low rev driveability.

fred cook · fred cook's Garage

In a way I agree with Goran. Unless.....you are going to have to do a top end job anyway. Now all you are out is the extra cost of the cams which makes the work more justifiable. Also, I know first hand the effect of adding SSI exhausts to a 3.0 engine. That one change made my SC sooooooo much more fun to drive! Of course it would be nice if one had the $$$ to go ahead and increase the compression and maybe move up to 3.2 liters, etc. But, sometimes the fun is in taking small steps and savoring the results.