Mark Basch superchargers (my opinion)

[mick]

If you use a 9psi pulley and dump all pressure above 6psi will the air temperature from the blower be any hotter than the 6psi pulley? The reason I ask is that as you dump excess air the back pressure on the blower would not be greater than 6psi.

[This message has been edited by mick (edited 05 September 2002).]

 

[BoostedMR2]

LOL! This board sure has a propensity to get heated over some pretty non-controversial topics lately.

What?!? Blow-off valve? Pop Off Valve! I KEEL You!!!!

For a while I thought it was just me, but I guess not.

-- DavidV

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Get Boosted!
www.boostedgroup.com

[This message has been edited by BoostedMR2 (edited 05 September 2002).]

 

[sjs]

Originally posted by matteni:
It's been a LONG time since I had thermo and studied combustion engine technology but wouldn't you be better off with 6lbs near ambiant temp vs. 9lbs at a MUCH higher temperature?

If your engine could tell you which one IT likes better - I bet I know what it would say!

Any "practicing" engineers want to chime in with a bunch of the formulas I have forgotten with all the beer I drank!

An ex-ramblin wreck from Georgia Tech and (once was) a hell of an engineer...

Not being a trained engineer, much less a practicing one, I don't have a factual answer but I do have a few comments. If the aftercooler drops the pressure by more than 1 psi then I’d consider it inadequately designed. Other than that, not doubt there is a point where a smaller but cooler/denser charge is better than a larger hot one but given the HP they appear to get at 6psi I’m guessing that heat is not a big issue at that pressure. (Although that may be quite different when run hard in the real world.) So if the new pulley and cooler allow +2 or more psi with the same inlet temperature then a think a significant net gain is there. However, since the desired increase is in the lower range then the actual CFM being pushed from 3-6k RPM (before it’s bled off) is still in the range of what it pushes right now at 7-8k. Of course CFM isn’t the issue, it’s the heat of compressing the air, so perhaps I’m off the mark there. But is that air ever really seeing 9psi, or are you just processing enough air (CFM) to generate 9psi if not for the relief mechanism? If you can’t plug a boost gauge into the system anywhere and see more than 6psi then I don’t think you’ve heated it as if pushing 9psi. The heck with an engineer, call in the physicists.

Something that hasn’t been mention much is the fact that your SC is being turned faster with the new pulley which likely means faster wear on belts and the compressor itself as well as (possibly) lower efficiency of the blower.

Next!

 

[nsxxtreme]

I would have to agree with Lud and True here. If the device does a function that already has a term for it then use it. Just because you may have designed it doesn't mean you can call it whatever you want, unless it has some new function. This will only confuse people, exspecially those who really know what they are talking about. Along with making the rest of us look like idiots when we try to descibe what this device does.

 

[nsx1164]

Originally posted by kpond:
In answer to the question posed by nsx1164:

There is at least one measureable downside to the BOV (or POV, if you prefer). In theory, you run a smaller pulley so you have more boost available especially at lower RPMs and then you set the BOV to bleed off the the boost above a set psi, say 6psi, for example.

The downside is that at the higher rpms where you are bleeding of "boosted" air, you will have the heat associated with the higher psi level - which is potentially significant. Let's say you have a BBSC and you go with a 9psi pulley (9lbs at 8K rpm) and you set a BOV at 6psi. Well, in this example, you will still have 6psi at 8k rpm but you will have the heat associated with the work generated to get 9psi of pressure.

This is the main reason that MB was (is?) only thinking of going with the BOV for the aftercooler-equipped cars. However, I for one would be interested to see the measured temperature differences between 6psi and 9psi and then make a decision from there. Likely the data is out there as the Paxtox is popular with the Mustang crowd where the number of installed units is much larger than the NSX.

OK -- so getting the high-boost pulley with the to-be-named boost limiter valve gives you:
- increased boost (power/torque) at lower RPM
- no loss in boost at higher RPM (note that there might be efficiency losses due to the elevated temps as the blower is producing 8-10 lb boost at high RPM)
- probably a flatter torque/power curve (more like the CTSC, shape/slope wise ?)
- needs an aftercooler to work
- any other "considerations" ??

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Do you need:
(a) larger injectors ??
(b) more engine tuning ??
(c) cat removal ?? (so facilitate A/F tuning in (b)
(d) more complex fuel management (?)
(e) others ?? -- uprated engine cooling ?

 

[Yellow Rose]

A - not yet determined to be mandatory, but one of the earlier setups may include larger injectors for two reasons - pulse the larger injector for a shorter duration to make it last longer and as tuning takes the engine to increased HP, there will be extra fuel available.

B - not sure exactly how to answer, other than to offer up that a different controller will allow more refined tuning.

C - while cat removal is often done for tuning, it is not a requirement. Weld a bung to an exhaust pipe for an independent wide-band O2 sensor. WBO2 sensors are supremely reliable for tuning than the stock O2 sensors. (In fact, the OEM sensors are completely useless for accurate tuning.) If one uses a dual channel controller, weld another bung on the other exhaust pipe.

D - yes, see B.

E - there are some reports of overheating problems, but none crippling. Various solutions are being mulled over, including an external oil cooler.

[This message has been edited by AndyVecsey (edited 06 September 2002).]

 

[cojones]

When are the first of these high-boost with to-be-named boost limiter available ??

Any preliminary test results ??

 

[ScienceofSpeed]

hi Chuck --

I remember riding with you at NSXPO. I think I'd need some sedatives to ride again with the BBSC!

-- Chris

Originally posted by Chuck:
I was one of the "road trip" beta installs. The first (beside Nick) with an OBDII car using the SS box. Like most new software, it wasn't bug free at first. After installing a new software program in July, and going to two track events since that new software install, I must say I got my moneys worth. In my most recent event, one of the more telling moments were not so much me passing two Vipers, but pulling away from them on the straights. I know exit speed has alot to do with that, but I also realize I now have power on the track that I wished I had before the install. I may have had doubts right after install, but the new software has done wonders. Now I can't wait for the BOV.

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Revolutionize your NSX with ScienceofSpeed
www.ScienceofSpeed.com | [email protected] | 877-863-4520

 

[G_Man_Max]

Thankfully (well mediated LUD) since we all seem to have finally decided on the correct terminology for the various available automotive acronyms associated with forced induction. I feel that to be "true" to the spirit of "True's" obsessive compulsive attention to detail we should also clear up a little electromechanical terminology.

Originally posted by true:
start with a static spring and use a boost selenoid to operate it.

when the pressure reaches 8lb's the seloid switches the pressure source to the pop-off to open it.

This way you could run 4,5,6,7,or 8 by adjusting your selenoid. B]

What I believe you were contemplating True is the use of an electrically operated SOLENOID (http://www.detroitcoil.com/whatis.htm) to control a valve in the air intake between the supercharger and the engine's inlet tract. This would work equally well on supercharged or Turbocharged applications and is currently in use very successfully on a number of World Rally Championship teams works vehicles, I have also used such a systems on a NISMO 400R Skyline where both the pre turbo MAP sensor and an Entran ( Http://www.entran.com/autospcov.htm#AirInletBox ) post turbo boost pressure sensor were used in conjunction with on board processors and the ECU to adaptively predict the boost in real-time, this data modelling was used to control a variable rate air discharge valve to maintain almost perfect boost conditions.

So True, excellent idea lets hope someone MB, Gerry, Larry, FactorX etc creates the appropriate hardware for the NSX. And at the same time why don’t we see more people upgrading to something like the AEM ECU when there investing so much in FI ??? SS ar other “MAP fooling” widgets can only take you so far….

 

[tunapie]

I added a Techedge WB and you can bypass the adding extra bung. I replaced the rear O2 sensor with the WB and made a harness to connect the rear 4 wire plug to the front. This joins the front and rear siginals. You need 2 male and one female connectors. So far the ECU is happy with no falt codes. Dan

 

[MYNSX]

Its dial in time for the BBSC!!! www.mynsx.com