 |
|
|
1994-2002 [Subscribe to Daily Digest] |
Members do not see ads below this line. - Help Keep This Site Online - Signup
MBC Anticipator
For T-5 Engine Management Cars
Dean is the mastermind behind this experiment
I’m just the guinea pig
Parts List:
MBC – Manual Boost Controller
Air Pressure Regulator
Two ¼ inch Male Hose Barbs
1 Coupler
2 Y Connectors
Teflon Tape
Vacuum Hose
Zip Ties
Premise:
See Dean’s post for MBC Anticipator or search drs_anticipator
He can explain it best.
The problem with Manual Boost Controllers is in the name, Manual. In the changing temperatures, cooler outside air positively affects boost. The MBC is typically adjusted and raised until fuel cuts begin to happen, somewhere around 15.5 psi, then backed off for the “sweetspot” for the maximum amount of boost without a fuel cut. As Dean has pointed out in earlier postings, the problem arises when outside air temperatures begin to drop which changes the setting’s because cooler denser air charge at the same pressure limitation will you more power and we begin to experience fuel cuts where before we had not before. The T5 limits boost pressure, not air mass flow Especially in higher gears, the turbo comes on too fast for the wastegate to open, which creates pressure spikes thus causing new fuel cuts.
Dean Continues:
“Once boost starts to build the regulator will flow to the WGA, but it will only apply pressure up to the regulated pressure, and no more. Because of the MBC's bleed orifice, there will be a continuous flow through the regulator during the phase before the MBC cuts in. Once the MBC starts to flow, the pressure in will be above that of the regulators setting. At that point the regulator will not flow and the MBC sees business as usual, but the WGA is pre-pressurized.
The idea is to reduce the pressure overshoots. If you have a 3 PSI pressure overshoot, then you have to adjust to a level of 12 PSI to avoid fuel cuts. And the size of the overshoots will increase in the cold. So by reducing or eliminating pressure overshoots, then you can increase your boost closer to 15 PSI without triggering fuel cuts with the overshoots. That will allow greater boost and power and avoid fuel cuts. So a lot of benefits if it works out.
Setup:
(Note; The Air Pressure Regulator currently has a gauge, which I plan to take off due to its uselessness and possibility of being damaged from heat and vibration)
1. Similar setup for the MBC, low pressure side of turbo to first Y connector
2. One side of the first Y connector to short hose of MBC inlet
3. Other side of first Y to short hose to air pressure regulator
4. Short hose off MBC outlet and short hose off air pressure regulator to Second Y connector
5. Single hose to wastegate
Outside temperature at Time of testing was 62 degrees F
Before connecting the new setup, I took the car out for a quick spin and experienced fuel cuts at 62 degrees
I tested the air pressure regulator with shop air to pre-set it to 3psi
Left the MBC at it’s original setting
Connected the new setup and went out:
Here’s the first three tests
Test#1 – APR set at 3psi, MBC at original setting(high)
Observations: Boost pressure was reduced from previous max boost
Conclusion: APR is allowing too much air, opening wastegate earlier then wanted – No Fuel Cut
Test#2 – APR Closed off allowing no, MBC untouched
Observations: Max boost and fuel cuts
Conclusion – APR is working
Test#3 – APR open a bit but less than 3 psi, MBC untouched
Observations – WOT, turbo gauge ¾ in the red, holding steady to 110 mph, no Fuel cuts
Conclusions – not jumping to any yet
Test#3 ½ - slow down to 85mph, holding steady at 3100 rpms, turbo gauge shows white, go WOT, turbo build extremely fast, turbo gauge goes deep into red, in no time flat at 100mph – no fuel cuts
Let off to approx 88mph, turbo releases, go WOT gauge 7/8th into red all the way to 115mph, no fuel cuts.
Conclusions: amazing performance, no fuel cuts, seems like anticipator is doing its’ job.
I will post results again in higher temperatures to see if anticipator negatively affects boost levels in warmer air.
I have a few pictures of the setup, will post the final setup here with others to follow.
Thanks to Dean for his never ending brilliance and pursuit of pushing the envelope on the cars we love.
posted by 208.235.174...
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.
 |
 |
 |
 |
 |
