|
|
|
|
| Author |
|
|
Registered
|
Camshaft suggestions
Hi all
Hoping to get some advice/suggestions on camshaft "upgrade" Currently I have a 1990 3.6 in my 1979 911sc. It was rebuilt about 4yrs ago and in its current form looks like this: 1. Pure Performance Motorsport Rods 2. Cams: Cup cams "993ss" 3. Supertec headstuds 4. Clevite rod bearings 5. Titanium valve spring retainers 6. Aase (aasco) valve springs 7. CP carillo pistons 11.5:1 8. European racing headers 42mm ID 9. injectors 750cc (ASNU) injectors 10. AT Power ITBs 11. EFI: Motec M130 ecu 12. Exhaust - European racing headers 42mm ID 13. Heads are stock I use the car semi regularly on the street, but also try and get to the track at least every month or two. I have had a reliable/reputable source tell me that I could be leaving a decent amount of power in the table with that particular cam choice for this engine. I'm hoping to get some advice/suggestion/thoughts re: camshaft upgrade Thanks 
Last edited by TAV; 04-08-2021 at 02:43 PM.. Reason: incorrect header diam - typo |
||
04-06-2021, 04:42 AM
|
|
|
Registered
|
I have a set of unused race cams from Elgin Cams. I believe they are 324 degrees inlet and 318 degrees exhaust duration @ zero lash. I can't remember the lobe separation angle or lift. Probably around 102 degrees and pretty high lift. The duration and LSA should not be a problem for your ITB set up.
Please PM me for more info.
__________________
1985 928 S3, 5-speed 1987 Carrera, current project 2012 Jaguar XF 5.0, Wife's d.d. 2009 Boxster,sold, 2000 Boxster, sold, 1995 993, sold, 2004 Maserati, sold, 2000 996, sold, 1971 914, my college car, 1966 911, sold way too cheep, Lots of VW's... |
||
|
04-08-2021, 04:09 AM
|
|
|
I would rather be driving
Join Date: Apr 2000
Location: Austin, TX
Posts: 9,108
|
What do you want to change about the engine?
A proper cam choice will use head flow vs lift to match and maximize cam lobe lift. Then duration is set to match power band rpm. Lobe separation can be set based on induction and fuel delivery system. I will assume that your overall torque magnitude is somewhat fixed by the head flow and compression ratio and timing. There may be gains to be made by changing lift. Yes, adding exhaust duration will shift that available torque to higher rpm and give you more HP reading. A dyno curve will tell you where you are making power in the torque curve and how much drop off there is at higher rpm. Typically cams can really help fill in the top rpm "hole". You appear to have everything you need to maximize the power output. Just keep in mind that more cam means more rpm. Make sure the bottom end can support this...
__________________
Jamie - I can explain it to you. But I can not understand it for you. 71 911T SWT - Sun and Fun Mobile 72 911T project car. "Minne" - A tangy version of tangerine #projectminne classicautowerks.com - EFI conversion parts and suspension setups. IG Classicautowerks |
||
|
04-08-2021, 06:53 AM
|
|
|
Puny Bird
Join Date: Nov 2002
Location: Port Hope (near Toronto) On, Canada
Posts: 4,566
|
If you drive on the street you don't want to over cam the engine.
On a twin plug 3.0 I have WEB 120/104 cams, totally driveable with good idle under 5K RPM, but it screams 5K and up. I'm happy with it.
__________________
'74 Porsche 914, 3.0/6 '72 Porsche 914, 1.7, wife's summer DD '67 Bug, 2600cc T4,'67 Bus, 2.0 T1 Not putting miles on your car is like not having sex with your girlfriend, so she'll be more desirable to her next boyfriend. |
||
|
04-08-2021, 06:55 AM
|
|
|
Registered
Join Date: Mar 2019
Posts: 1,601
|
Is that 52mm ID a typo? It really has 2 1/8" primary headers?
|
||
|
04-08-2021, 07:05 AM
|
|
|
Registered
|
sorry, yes, headers are 42mm ID. *edited original post
Thanks for the replies thus far. In regards to the bottom end, I'm comfortable with the rods and pistons. It is still running the stock 964 crank. |
||
|
04-08-2021, 02:51 PM
|
|
|
