3" intake on 98 set [Archive] - SaabCentral Forums

: 3" intake on 98 set

11-01-03, 07:25 AM
I made an intake today, the car seems to rev more but there seems to be less midrange torque. Is this possible? Id have thought the more air the better, but I think I saw a post (?from ERP) re tuned length of stock intake being good for torque.I'm going to change back- fortunately in Australia the drain pipe we have fits neatly over the inlet, hence no disfigurement!

Maybe Im just a sad case, but I like the midrange,I'm not interested in revving to 6k in each gear.
BTW any ideas on how much power the auto box will take, the Abbott dealer here in Aus thinks maybe not too much over stock?
Oh I took out the tbtc and couldnt find a 'lip' ie there was nothing to grind.Am I missing something ?

98set/mbc/kn/saab roadholding kit/eibachs/probably stock intake !

11-01-03, 12:49 PM
I also made my own 3 in intake, and did notice the loss of midrange torque. This dissapointed me, until I installed my sport exhaust system, which seemed to level out the loss of torque.

17-01-03, 03:44 AM
Yes, changing exhaust, intake, and port size and length can to things with torque and horsepower. The basic idea is smaller diameter longer length for more low end torque, and wider diameter shorter length for more high end horsepower.

The idea behind it is that the small diameter longer pipes get air moving thru them at a certian speed so that the air in motion stays in motion. This will either force air into the cylinders or suck exhaust gases out of the cylinders. But when the RPMs get higher too much air has to travel too far thru small spaces thus restricting the flow.
When tuning for horsepower the larger diameter is used to allow for more airflow.

This is how NA engines tuned for race can get over 100% volumetric efficiency (volume of air in cylinder for the volume of the cylinder)

Jeremy R.
17-01-03, 01:45 PM
I had a BSR conical air intake, and lost all sorts of low-end torque with that thing, and gained some pretty weird intake noises. High RPM horsepower (which I don't use much) was better, but I didn't like the loss of torque. I took it out, but I replaced the stock airbox's tube with a 3" piece of bell-end PVC pipe that was exactly the same length as the original. I enlarged the hole in the airbox, shoved the PVC pipe in there, painted it black, and sealed it up with black roofing caulk. Low-end torque was much better than it was with the BSR intake, the bizarre intake noises were gone, and high RPM horsepower didn't seem to suffer. I also have a K&N air filter, if that makes much of a difference.

Tweek's Turbos
17-01-03, 08:39 PM
Anybody ever think of turning the passenger side of the bumber into swiss cheese and then kinda making a ram air set up with the outside bumber? Hmmmm I wonder :-??