Thanks koejing, I'll make the needed changes to my circuit... I should be recieveing my MAP sensor Friday and hopefuly my newly SCd car on Sat maybe late Friday

I had a long question and answer session with Chad today, he's the guy who designed the SC kit... he's a good guy and very informative.. He seemed to think this design would work but didnt originally consider it because of the cost. He has however located a new check valve with lower cracking pressure and a higher flow rate, Keith (Silver Surfer) is now the second car to have it installed. I can tell you that this new valve makes the SC perform even better then the best it did before... one place you really notice it is in the gas mileage. Keith was getting at most 180 miles per tank before the valve install and now after returning from comptech he is now at 1/3rd full and 180 miles This is good news for both those that want to stay with a check valve design and those of us persueing an electrical design. This basicaly confirms that the ECU reacts proportionaly to any boost it sees on the map sensor, Chad seems to agree with this as well. Hence an electrical solution should provide near ideal performance (mileage) and the new check valve ever so slightly less.

BTW Comptech has sold/delivered ~25 SCs and has a back order of ~30... Also if any of you are in N. Ca you got to stop by this place the Crew and Shop are top notch.

[Edited by davepk on 03-29-2001 at 08:03 PM]

 

Dave:

Thanks for the update! I am interested in seeing how the three proposed solutions fare in actual vehicles. Keep us posted....

Stan:

The MAP sensor supplied with the vehicle is probably capable of handling the boost levels provided by the Comptech SC (RT mentioned a 10-12psi linear cut-off). In addition to the MAP sensor, the ECU has an on-board barometric pressure sensor that it uses to calculate "proper" fuel/timing. My guess is that as soon as the ECU reads higher pressure at the MAP then it does on its onboard sensor it runs home to mamma and puts the car in some "fail-safe" mode until the condition clears (hence the need for breather valves, electronic black boxes, etc.). I totally agree that a proper solution would be to provide an ECU upgrade which is capable of properly handling this boost condition. This would eliminate the need for any black box type solutions and allow for easy upgrades via new ECU code releases. But somehow I doubt that Honda would be willing to provide "outsiders" with the intimate design/programming details of their ECU.

-koejing

 

koejing, According to Chad the ECU will respond (by retarding timing) linearly to the boost seen on the MAP sensor up to a point, at some limit it then will declare an error condition and throw a code... Thus it is very important that the map sensor not see any boost. It also explains that even with poor check valves and some boost on the MAP sensor the car can still run without throwing a code. He also mentioned that he thinks the S2K ecu was the only honda ecu to incorperate a baro sensor in the ecu. he said the other or older ECUs would take a reading off the MAP sensor before engine start and use that as a baro reading to compare to the MAP sensor. He also said that yes this does cause problems during changes in altitude... and that the S2K has no such dificulty. Indeed in using his PGM tester from Honda he can see the baro pressure drop as he goes up in altitude as well as the MAP sensor showing the same lower WOT manifold pressure. Comptech is at the foothills of the Sierra thus altitude changes are easy to come by...

[Edited by davepk on 03-30-2001 at 11:13 AM]

 

Well, i got it together, MAP sensor and all, ready for install. Tested it on the work bench and it operates as advertised, local pressure outside... 2.83V
Now i just need my car

 

Dave, both you and koejing are impressing the hell out of me!

So, what's the final cost of components (not counting your time or the 2nd MAP sensor)?

Is this truly cost prohibitive (Comptech?)?

Thanks for guinea pigging for the Team!

 

I second RT's sentiments, excellent job.

IMO, to get comptech to pick up the tab for this solution may be asking too much, especially if the new check valve and bleed orifice work well. This circuit would need to be packaged to withstand the rigors of life under the hood of a car, for the life of the car (or at least the life of the sc ). This packaging is probably what will drive the cost.

I would be willing to pay for this fix, if it could be shown to be better than the mechanical fix and it doesn't cost too much (< $100). Are we talking Mingster's Supercharger Boost Inhibitor?

 

[QUOTE]Originally posted by rocketman
[B]I second RT's sentiments, excellent job.

IMO, to get comptech to pick up the tab for this solution may be asking too much, especially if the new check valve and bleed orifice work well.

 

[QUOTE]Originally posted by krazik
[B][QUOTE]Originally posted by rocketman
[b]I second RT's sentiments, excellent job.

IMO, to get comptech to pick up the tab for this solution may be asking too much, especially if the new check valve and bleed orifice work well.

 

Sorry Krazik, RT is right... the ECU is located behind the drivers left side kick panel...just below the fuse box.

 

dave, where did you mount the 2nd MAP sensor?
With the device near ECU or under hood with TB MAP?