Methanol and map sensors

[Dave Flanders]

Did a search but didn't see this directly addressed.

Is anyone aware of any problems associated with large amounts of methanol and a standard GM map sensor? I don't know much about Buicks (sorry, 2.3 Ford guy here) but am assuming they are located near the plenum? Maybe off a vacuum tree?

Reason I ask is I'm planning on eliminating my IC and adjusting intake charge temps with one or two aux. nozzles (car runs on methanol) at the turbo outlet. The volume of fuel will be relatively large - I'm guessing up to 20% of my total fuel flow - and am concerned about the fuel attacking the innards of the map and to the same extent the wastegate diaphragm.

Pardon my ignorance which is staggering.


Half Fast Racing

 

[4sfed4]

Well....I am running about 212 lb/hr of methanol (and about 208 lb/hr of gasoline) and so far, no MAP sensor problems.

I guess that theoretically some vaporized methanol might be in the pressurized air which reaches the MAP sensor, but I would guess this amount is insignificant.

Plus...we have the many thousands of hours of combined usage on cars running alky injection to fall back on as well. I havent heard of any MAP sensor failures as a result. Has anyone else?

 

[Razor]

Not an issue. I've been running alcohol for 2.5 years.. no issue on same MAP sensor. Thats about the only thing on my car I havent broken

 

[Dave Flanders]

Thanks guys- it's not something I've ever seen addressed, hopefully it's because it's not a big problem. I'm still working on trying to feed the vacuum/boost referenced items from an area that won't see a lot of fuel.

Larry - 212 lb/hr of alky huh? That's more than I would've expected from yours! I'm looking at a total fuel flow next year of maybe 975 lb/hr. Now I'm trying to get a feel for what nozzle size will be required to cool the charge from 400+deg down to about 120.


Half Fast Racing

 

[4sfed4]

Originally posted by Dave Flanders

Larry - 212 lb/hr of alky huh? That's more than I would've expected from yours!

More than I expected too. See this post----

http://turbobuick.com/forums/showthread.php?s=&threadid=142526

I'm looking at a total fuel flow next year of maybe 975 lb/hr. Now I'm trying to get a feel for what nozzle size will be required to cool the charge from 400+deg down to about 120.


Half Fast Racing

With what appears to be a massive airflow rate (I am assuming this based on your fuel flow number), you are going to have your work cut out for you dropping that intake charge down 280 degrees! I think Razor did a test on a very stout Buick where intake air temps were actually measured. A post was made awhile back. Maybe a link could be posted.

 

[Razor]

http://www.turbobuick.com/forums/showthread.php?s=&threadid=134330&highlight=hartmans



Possible new dyno testing this week on Cal's car... shhhh... dont tell anyone.

 

[Dave Flanders]

If you could find a link that would be great.

The numbers I'm looking at are very loosely based on top alcohol stuff. They're putting about 30% of their fuel on top of the blower and obtaining charge temps of under 200F. Considering a roots blower would have discharge temps considerably higher than a turbo I'm hoping what I'm attempting is possible.

T72 @ 40psi boost should = about 400-425F.


Half Fast Racing

 

[Dave Flanders]

The link popped up while I was (slowly) typing. Thanks Razor

 

[bruce]

Originally posted by Dave Flanders

Reason I ask is I'm planning on eliminating my IC and adjusting intake charge temps with one or two aux. nozzles (car runs on methanol) at the turbo outlet.

You do need to take some precautions, since with alky your partically saturating the hot air with vapor. So you can have condensation take place, and it can accumlate in the MAP sensor. Keep the sensor high, and the line feeding running downhill to the manifold so that any condensation, gravitates back to the manifold.

Don't ask me about how I know you can fill a MAP with alky.

 

[4sfed4]

Originally posted by Dave Flanders

T72 @ 40psi boost should = about 400-425F.

Assuming an 80 F inlet temperature and 14.7 psi ambient pressure with 40 psi boost----

400 F discharge temp = 77% compressor efficiency

425 F discharge temp = 71% compressor efficiency

Looking at a T72 map, those efficiency numbers look like they are in the ballpark so I think your estimates might be close.