Tuning for bigger cams - Saab Performance Bulletin Board - Saabnet.com
NG900 & OG93 |
Vintage Models |
Clubs & SOC |
Other Cars |
Member Photo Galleries |
Member Directory |
*Buddy Registry |
*Mileage Registry |
What's New |
Photo of the Month |
[Main Performance Bulletin Board | Post Followup | BBFAQ ]
[ Prev by Date ] [ Next by Date ] Member Login / Signup [Latest Member Gallery Photos]
Tuning for bigger cams
Posted by 85Turbosled [Email] (more from 85Turbosled) on Sun, 13 Sep 2015 12:17:21
Just looking for insight on tuning my recent install of some custom high(ish) perf cams.
Engine is an '85 with '88 pistons with slightly ported & matched 2.1 head and 2.1 manifold, FMIC, bigger injectors, 3"DP, 2.5" exh and many other little things.
compression check before cams was 180psi even in all 4, now its 150psi! Now im aware of course that cams can affect cranking pressure, but I didnt expect this much! Idle vacuum went from 21" to 16" so thats not horrible I suppose.
whats bothering me is the amount of timing I am now needing in this engine to get it to knock under stock boost is crazy. Old timing numbers around stock boost levels are as follows:
BTDC AT 11PSI
with the new cams installed in order to get repeatable knock the timing numbers look like this:
BTDC AT 11PSI
Initially without remapping timing, the car was an absolute dog, but after remapping the entire timing map, the car seems very nice, and on boost it absolutely rips your face off, especially +4000 revs!
has anyone experienced this happening on their Saab?
I of course realize that in order to make the best of any cams, especially aftermarket cams, I WILL need adjustable timing sprokets, and I will also have to phone back the person who made them for more specs so that Im able to correctly time them (LCA, Lobe sep, installed lifts, timing events ETC) but for now I just want to go fast and have fun (safely)
cam specs that I know:
Primary lobe, Duration @.050": 218Deg, .365" (9.3mm) lift
Secondary lobe, Duration @.050": 220Deg, .340" (8.65mm) lift
Duration @.050": 218Deg, .365"(9.3mm) lift
any feedback about tuning for more power and the odd timing amounts is appreciated, and yes I have checked that the cam marks line up exactly at TDC to the marks on the caps
posted by 70.69.16...
Posts in this Thread:
Post a Followup
No Site Registration is Required to Post - Site Membership is optional (Member Features List), but helps to keep the site online
for all Saabers. If the site helps you, please consider helping the site by becoming a member.
This is a moderated bulletin board - Posting is a privilege, not a right.
Unsolicited commercial postings are not allowed (no spam). Please, no For Sale or Wanted postings, SERIOUSLY.
Classifieds are to be listed in The Saab Network Classifieds pages.
This is a problem solving forum for over 250,000 Saab owners, so expect to see
problems discussed here even though our cars are generally very reliable. This is not an anything goes
type of forum. Saabnet.com has been a moderated forum since 1988. For usage guidelines, see the
Saabnet.com Mission and Purpose Page. Please remember that you are
not anonymous. Site Contact | Site Donations | Other Sites by SP -
Your address is: 220.127.116.11 - Using CCBot/2.0 (https://commoncrawl.org/faq/) - Logged.
Site Members do not see red text instructions, bottom of the page anchor ads, or box ads.
Click here to see all
the Site Membership Benefits!