3.0 rebuild for performance advice
 

I'm trying to figure out the best bang for buck in an engine performance upgrade/modification. The engine is a small port (1982) 3.0 with 120K miles. It had a top end and new rings at 95K, it has the original head studs I believe. Currently have stock CIS, SSI headers and Classic Retrofit CDI upgrade. I'll be doing my own work.

These seem to be my choices:

1. Don't open the engine, just add the following bolt on & tuning Cost ~ $500-$800. Expected gains = ???
- Set Cam timing to Euro
- Recurve the dizzy to Euro or replace with 123-ignition adjustable model.

2. Above PLUS new 10.5:1 CR pistons & cylinders. Clean up heads & keep single plug. Change head studs while I'm in there. Cost ~ $7200 Expected gains = ??? Also, do I need to replace the cylinders with these pistons, or can I run with the stock tubes?

3. Above plus more aggressive cam. Cost ~ $8200/ Expected gains = ???

It's the expected gains I'm trying to figure out of course. Any input will be appreciated. And if someone has thoughts for a different set of or additional mods, please speak up! Thanks.

Read through this: http://forums.pelicanparts.com/porsche-911-technical-forum/163860-best-cam-profile-stock-sc-3.html

You’ll see some interesting comparisons of torque and HP curves for small port v big port SCs. You’ll be surprised by the relative torque and HP of the small port 3.0 up to about 5500 RPM. Then it runs out of puff. Basically, it’s the intake port size that’s the limitation and more fuel won’t necessarily help you if engine can’t breath. So I wouldn’t do anything major without addressing that.

Also, don’t go to 10.5:1 without going dual-plug. If you’re changing P&Cs you’ll get more bang for your buck with displacement anyway. Both would obviously be ideal but then you’ll need to dual plug.

Also definitely worth checking out Al_Kosmal’s build threads here. Search his threads and look at the 3.0L builds. You’ll see some seriously impressive before and after shots and some dyno numbers of what a 3.2SS might spit out with and without EFI. The with EFI #s are impressive and not too late to ask Santa.

PM sent
Ian

When I built my 3.0L I built it to be bullit proof. I was doing a lot of track days and wanted something I could drive to the track, drive the daylights out of and drive home and only need to adjust the valves and change the oil once a year.

Consequently it had 9.5:1 pistons, twin plugs, webers and some racing tricks that would allow it to turn 8000rpm.

It did have the small valves but with the advise of my friend Jeff from Seattle we both went with a custom cam grind that lowered the torque peak (you need torque to pull out of the turns) but still developed peak horsepower at 6800rpm. Torque is 227@4800 and horsepower is 245@6800.

What is your personal best bang for the bug? Street performance with having more torque at mid revs or .... more power obtaining at high revs? Thats what let get things/approaches here more specific.

Setting cams to 0.9-1.1 will lower torque at mid revs and rise power at high revs.
As you already got a Retrofit CDI device I guess you also are aware that you can lock the distributor and set your own individual ignition curve easely via the software coming with the Retrofit product – so no Recurving of the dizzy oir even a purchase of a 123 ignition device is needed. The only plus of the 123 Ignition dizzi is in your specific case that it also supports a more aggresive vacuum advance cause of the ported vacuum support.

Whith a more agresssive ignition timing curve you will really beyond the limits with a CR of 10.5:1 as detonation is really risky here without knock sensoring.


Depends on the cams profile, but .... nearly all of them will force you to run the engine at high revs to really "noticably" feel the gain.

And here is where the small ports will be the bottle neck as at very high revs the airflow is limited compared to big port heads/manifolds


With all the money you're able to spend, I really would think of changing to EFI with a full engine management.
https://www.elferliste-service.de/index.php?/topic/8313-sc-mit-pmo-einzeldrossel-und-kms-efi/
(use an online translator) Unfortunately the pics aren't linked anymore.

For all other approaches like SSI, retading cam timing, 964 cams etc etc. See the end of my workshop in the link in my sig

That's a great link, thanks! The car is for mostly street use. So midrange torque is probably what interests me most. I did not delve into the Retrofit CDI programming, but it looks like this is very much in order, thanks for the tip!

I'm getting a lot of input on an EFI conversion, which I had not thought of initially, but it looks like a good place to start. So, I'll change option #1 to EFI/ITB setup plus more aggressive timing. From what I can tell from my searches, I may be adding 30+ hp and lots of torque and throttle response with this mod, which seems to be worth the cost.

If 10.5:1 is too much compression, do you think there's enough gain to be had with a tamer P&C set up than what I mentioned, as in 9.8:1 (Euro)? It looks like in a stock car the Euro setup adds 20hp and proportional torque. I should add that cracking the engine open is not my first choice, but since I have original head studs there's some motivation to get in there and replace them. So changing the pistons makes some sense effort-wise if I'm going this route, but if it only adds 10hp I'm not sure it's worth the thousands in parts.

Can you tell me more about the vacuum advance advantages on the 123 dizzy? Just curious.

the 123 dizzy (the bluetooth one for 6pin CDI which you would need) comes with vacuum support, means with an integrated vacuum sensor and external vacuum hose connection where here the ported vacuum from the throttle body will be read and interpreted/ported to an extra ignition advance you individually can set up by software/app, like the mechanical advance.

I have a US spec 82 Targa that started life in exactly the same place - US small port heads, etc. Though mine had nearly 200k miles on the engine when I bought it.
I started by reading the Bruce Anderson book from cover to cover, then doing what you are doing by talking to people on the forums.
I ended up getting carried away, but if you want a really nice road car, SSIs, euro Ps, 964 cams, the CDI+ ignition and better, more responsive induction (ITBs or Carbs) will transform the car. Open/flow the heads when they are off and it will be even better.

Put the M1 cam in it and the CIS will be happy with it.. KNIGHTRACE@MAC.COM

William , by M1 cam you mean the "Melissa cam" by web cam I. I spoke to Groovydude yesterday
He has lots to think about . I'll bet he'll choose the Melissa cam and high comp ratio pistons to go with CIS and probably include a WUR delete pressure regulator . this will bet the most cost effective. ian

You need to make the Warm Up kit for these people, The M1 is the Melissa cam. Melissa #1 is the code for M1

Ian, William, what is the Warm Up kit you guys mention?

More torque and 30 hp sounds like a nice thing, if it's not crazy money.
"Removing Weight" is always good to bring up, at some point, in these 'bang for the buck' discussions: zero cost.

+1

Sorry for the delay, Ian is working on a car up north, he is making the system for the CIS cars, email me at knightrace@mac.com and I will forward it to him. It seems excellent in my opinion, you can adjust your A/F ratio from inside the car.. I have nothing to do with it as I am on the other side of the spectrum. But email me and I will forward it. Thanks, William

my advice would be to not replace high quality nicasil Mahle cylinders with high risk aftermarket ones to get a bigger bore. With the small port heads stay with stock cams timed to 1.25 or so. With hotter cams you will be giving up low end torque while getting little or nothing back on top. 10.5CR is too much without twin spark. How about a set of Euro 9.8CR pistons from Mahle that does not require twin spark? Also; to run ignition advance from an ECU and lock distributor is not trivial wrt rotor phasing. The distributor rotor tip need to be aligned with terminal in distributor cap or there will be trouble. EFI does not add much if you already have a well functioning CIS except you will have a new hobby. I'd go with lightening car, 123 distributor, SSIs that you already have and a stock road muffler (not Sport) that will give slightly better torque below 4000 rpm. And do not open engine unless you know something is wrong. These engines age well

I agree with most of what Trond has written, however the M1 cam we developed on even an actual 8.2:1 compression 3 liter with small ports is gaining approximately 20 - 25 hp at the wheels. Ian has a set in his motor, we did not know the compression when he ordered the cams. I would have not expected that much of a gain on the lowest compression 3 liter with small ports. He has improved power across the entire RPM range. I personally prefer stroke over bore, many 3 liters here in the states haven't been rebuilt for 40 years and I feel it is a good idea to go through the motor in order not to see an expensive failure. There is a very high success rate even by non professionals. If your going to push the car on the weekends for spirited driving or DE or any aggressive driving there are some mandatory maintenance requirements and you can keep it pretty basic but most going to this level of work would like a little HP improvement.

Any effect on low end torque?

A follow up with regards to what KNIGHTRACE said . William and I have been working an a CIS system for fun HP and TQ. The test mule is a 1980 sc small ports , SSI, Dansk sport hotdog, pistons are 9.3 comp ratio , Measured to 8.2/ 1 static comp ratio, . Ignition timing is 30* btdc @3000rpm. The valve seats are in good condition,
Hot leak down test @80 psi in.... 79.5 psi held very good ring seal all 6 cylinders .
Two years ago I did a fun run dyno and got 188 hp @ the crank . That is my benchmark. I installed the M1 web cam with new rocker faces , set the cam to web specs @ .050". The change in HP was good at the seat of the pants , but I knew it needed more fuel. Next comes the WUR delete , I chose to run a fuel injection regulator in the cockpit , between the seats , Scott G has one too ! . I also installed an AFR meter in the clock hole . Wow that woke the engine up. I run the AFR @ 13.4 most of the time , cruise on the tpk and it's 14.7 , nail it in the canyons and it's 12.9. Any control pressure I set , will yield the AFR I want . So now It's time for a real dyno run , Mustang Dyno Eddy Brake. I have asked KNIGHTRACE to post the dyno sheet . I am having trouble with posting pics . 186 hp at the wheels and 184 TQ ... to the crank that is 219 hp and 217 tq. I just drove the car 2,000 miles to the east coast . I managed 28 mpg @80mph. when I arrived we set off to the drag strip , Ceicel county MD.
Kermit did not disappoint me . Our rules were no hard starts , just traffic light starts , My friend was running his 2018 Civic Type R,,, best run of four , was a 14.2 @100.89.....I beat the civic R by .010 sec . Great fun I hope KNIGHTRACE can post the dyno sheet 150 tq at 2500rpm
max tq 184 @4900 and held 150 tq untill 6600. It is a very nice combo with lots of GO.
When I get home I will put in a set of 9.8 Mahle pistons and proper squish clearance . We will see what we make then ! For a small port engine on CSI, this is a ripping car, 0-60 5.6 sec's , no doubt about it .
I will be putting a kit together for this combo. As to the engine up grades , valve and guide work is important , So are studs, fasteners , and rocker faces , piston squish area clearance 1mm on the money , rocker shafts , all measurements , comp ratio measurement , oil pump and bearings ,I also am a bigger fan of stroke than bore , ask me about bore to stroke ratios , If you don't know the condition of the part then you don't know , find out and write it down , enough for now .
Ian

We have a dyno comparison but it made more power and torque at every RPM level. It is between 30-40 hp gain at the flywheel. It made more torque from 2500 rpm up. did not test much below 2500 RPM. Ian had all the dyno numbers and results. I will try to help him post them later. WK

Sorry no pic posted

don't know
why

http://forums.pelicanparts.com/uploa...1604013996.png

http://forums.pelicanparts.com/uploa...1604014739.jpg

1980 911sc is car #704 , Civic type R is #703 , traffic light start
good fun
Ian

WOW that I plenty of information, I have used cams without any change to the CIS and it worked great especially on 9.8:1 Euro motors. However, I think the adjustable system is really inexpensive and worth doing. I built a euro 930/10 3 liter with these cams a few other small tricks, radian cut valves and 964 oil pump and made 237 @ the wheels. I sent a set to Michael D'Silva in Australia and he built a clients 3 liter there. He did not dyno it BUT he said it was the smoothest 911 motor he has ever driven. I will ask him to give his opinion. William Knight

hi Groovydude
(never thought I would say that to anyone!)

Yes, there are a plethora of things you can do to your motor. Where do you draw the line? I guess it comes down to where the car will be used primarily and of course your budget. If you are doing all the work yourself, well that saves a tonne of money.

I don't have as much experience as a lot of others on this forum, however I have built a few and driven different 3.0 cars over the last couple years...
The most recent engine I rebuilt started off completely stock apart from a set of SSi heat exchangers and a sports muffler. It only had the stock 8.5:1 compression pistons but it was quite torquey from down low (great for street) but ran out of puff around 5k.

Upon disassembly we found he had the 'big port' heads.. so we sourced a set of 9.8 used Mahle pistons and re-ringed.. at the same time, we chose to try the M1 cam that William Knight supplies. Pay careful attention to your deck height and your intake valve clearances as this is a much 'bigger' cam than stock (lots more duration).

No other mods were made. The CIS was left stock but treated to new gaskets.
The car runs a Dansk sport muffler but I am certain this muffler is slightly restrictive as while I was building this motor, I tried the Dansk on my own 3.0 car, and it definately felt slower at the top end... I think if the owner replaced his Dansk with something else he may see a benefit.

As William mentioned in the above post, this engine is the smoothest I have ever driven. It's almost freaky. Yes, I had the rods, pistons, pins etc, all balanced by the machine shop, but I've had that done with every other engine prior. This one is just so smooth. Is it the cam? I'm not experienced enough to say that it is, but that's the only thing different on this motor, compared to the others I have assembled.

It idles great, (little bit more exhaust note at idle) and is smooth and linear all the way past 6000... it almost feels like an electric motor it is just so smooth.

The owner loves it.. he only drives it on weekends through the hills and mountains but he keeps telling me how much more acceleration and how much harder it pulls everywhere. He doesn't seem to think we have lost anything down low, but it has not been dynoed (before OR after) so any perceptions of performance are purely that.

Again, we were very pleased with the result.

To give you a comparison, my own car is a 3.0.. I built it with 10.2 Carrillo pistons, ITBs, a full efi and ignition engine management system from Rasant, Headers, a GT3 muffler, bigger cams etc... and in all honesty, if my car had driven as well as the one above, I would not have spent all the money in efi. But that's just me.

Or go all out
I have a 3.2ss with twin plugs, 10.5 pistons, I’m not sure which cam as I didn’t build it, large port worked over heads, and Weber 46’s. Made 295hp at the crank.

The intoxicating rush of this engine cause me to run it to its 7400 rpm redline for the first two shifts even though first is almost unless as its spinning the whole time and its even sideways into second.

I bought a set of Itbs from Al. but haven’t bought an ecu yet. This is in my future plans.
Funniest car I think I’ve ever owned and I’ve owned a lot of fun cars.

Mike D'Silva, Thank you for the input and help to the community. It has been a privilege to work with you and see you help the people in Australia, I am Thankful to call you a friend. It is a great feeling to see such enthusiasm in the community. William Knight

CIS engine upgrade..........
 

Groovy,

Ian Carpenter came to visit me at home this morning with his green car with CIS engine. I have not met him until today and we talked mostly about CIS. We both share the same interest about CIS in general. And he invited me to get into his car for a short drive to show me his adjustable pressure regulator (WUR delete).

The adjustable pressure regulator is located between the two front seats with a round knob. And a complimentary AFR meter on the dash. So far everything looks normal and nothing out of the ordinary until he accelerated the car. You need to get into his car and experience yourself what this engine is capable of performing. I have been rebuilding stock CIS engines and never seen one like it.

I am a very skeptical person and not easy to convince. But my experience this morning riding in Ian’s car with a CIS motor is an eye opener. Anyone with CIS car wanting for a performance upgrade should consider this set-up. BTW, Ian lives in New Mexico and drove his car to the East Coast to visit his relatives. I just happened to reside nearby.

I will rebuild a motor using Ian Carpenter set-up. Thanks.

Tony

Tony , Thanks for the nice words . It was very nice to meet you . I am very impressed with your Lab for the work on the CIS parts , first class , data is everything when it comes to calibration.
I also enjoy your solve the problem attitude, and sense of humor . I am glad you enjoyed the performance from the 3.0 CIS engine in Kermit . The Key parts are the Cam , and the WUR delete .
With the adjustable regulator in the cockpit and the AFR meter on the dash it makes setting the mixture so easy. The Engine is a Small port 3.0 that is all stock with the exception of the M1 Cam and Regulator . More details on the 1st page . In the next months I will have a kit for sale
Thanks again Ian

The M1 cam seems to be the best we can put in a CIS 3.0. Great fuel economy, great power , also safer with todays fuels. THE WUR controller is really nice to be able to dial in the AFR's. William
KNIGHTRACE@MAC.COM

Knight, would the M1 be equally recommended for a 3LSC small port car running PMO's but still CIS pistons?

Either way the gains look amazing.

Like most say, ignition is the best bang for your buck (mechanical advance to 36˚). Open up the intakes, CARBS, yes carbs (PMO's or Webbers) the rest of your parts will work well. Have fun.

Geronimo, They will definitely be the best you can put on a CIS piston for PMO's. The only down side to them is where you have to meet emissions. I would actually try these before you open the Intakes or anything like that. They work on stock springs and you don't have to tear a motor apart to change cams. I changed a set in my SC years ago without taking the motor out of the car. They will also eliminate many of the flat spots on carbs without having to over reduce the size of the Venturi's in the carbs verses a stock cam. This is because they stabilize the vaccum in the intake sooner in the RPM range. I wrote a small article on Carb Basics that if anyone emails me wanting it I will email them the article. These M1 cams were developed to maximize the HP and TQ on a motor with CIS pistons no matter what is on top of the motor. My email is KNIGHTRACE@MAC.COM. William

Nice, we have no emission test in MI. :) It's about the only thing I can do without opening a giant can of worms. The numbers you are making is impressive for a cam swap. If my motor checks out I might have to give these a try this spring.

I have quite a few sets in operation will very positive reviews. I would like Andrewcologne in Germany to give a set a try. It would be nice to get a set in Germany. Thanks, William
email KNIGHTRACE@MAC.COM

I have been using a cam grind that is basically 993SS intake/964 exaust/114LC. Clears the 9.8:1 CIS pistons and runs amazing up top.

Recent 80SC 3.0 build on the dyno yesterday with PMO EFI ITB/9.5"1/Cam described above/SSI/M&K. Made 180+ ft# from 3500 to 6500 and 213HP at the wheels.

213WHP isn't to bad for a 3L, what size PMO's. I have a 3L, 46mm PMO, SSI, M&K and would love more oomph. Knight's cam sounds like a great with without going full stupid on a costly build for small gains.

Good numbers, I built a 930/10 euro 3.0 last year made 229 HP at the wheels no other mods, can not remember TQ but have dyno in computer.

213WHP would mean roughly 250CHP, pretty respectable bump from the factory 180!

Euro 3.0 has a higher HP in stock. Closer to 204 post 1980 vs US cars of same years. Still a great bump though!