MFR PP Housings vs. Everybody else
#1
Bourbon King
Thread Starter
Join Date: Feb 2001
Location: Louisville, KY
Posts: 667
Likes: 0
Received 0 Likes
on
0 Posts
MFR PP Housings vs. Everybody else
Ok here is my question. Is there any advantage or HP gains anyone has seen in using the MFR housings over say Racing Beat or anyother engine builders custom PP housings? I just ask this because of the huge price difference I see.
#2
MFR housings can't be completely duplicated.
Casting is quite different, sparkplugs are closer together, exhaust port opens later and has a smaller exit runner, waterjacket is relieved on sparkplug side to minimise housing warp........ to name a few.
Casting is quite different, sparkplugs are closer together, exhaust port opens later and has a smaller exit runner, waterjacket is relieved on sparkplug side to minimise housing warp........ to name a few.
#4
Rob at pineaple told me that for the 12a's he has gotton about 160-185 out of his hommade ones on an engine dyno and he is really good and knows exactly what he is doing. he said the MFR housings are a bolt together 290-310, He basically said that the MFR housings always make about another 15 horses at least. And yes there are differences such as the casting, exhaust runners, etc. I dont think the port timing can be exactly duplicated either, cus the MFR exhaust might open a little later than the stock ones. if any one is interested i may have a set of 12a MFR housings for sale, they are used but in very good shape, no chippingi in the sides.
CJG
CJG
Trending Topics
#10
Old [Sch|F]ool
Originally Posted by Rotortuner
I dont think the port timing can be exactly duplicated either, cus the MFR exhaust might open a little later than the stock ones.
The 12A's, in 1st gens anyway, open up at 75deg BBDC, so in that case the MFR housing would indeed open its exhaust slightly later.
In any event, they're all whopping shitloads later than what Racing Beat does.
#12
WTF is wrong with it now?
Join Date: Oct 2001
Location: London, ON
Posts: 1,492
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by peejay
(I have a rotor housing that I marked off every ten degrees, it's neat to see how the distance the seal slides per degree changes around the housing's shape).
PICS!
#14
Old [Sch|F]ool
I don't have a digital camera that works, even then I doubt it'd show up very well since I just used a Sharpie all around the circumference and then scratched lines and numbers into it.
#15
WTF is wrong with it now?
Join Date: Oct 2001
Location: London, ON
Posts: 1,492
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by peejay
I don't have a digital camera that works, even then I doubt it'd show up very well since I just used a Sharpie all around the circumference and then scratched lines and numbers into it.
Awright, so what's 5mm up and 5mm down worth in degrees?
#18
Old [Sch|F]ool
All the rotor housings have the same dimensions except for width (I know "the books" say they are different, but I don't see where when looking at them in real life)
I repeat my question though, where at on the housing? Near the top of the port or near the bottom?
I repeat my question though, where at on the housing? Near the top of the port or near the bottom?
#19
WTF is wrong with it now?
Join Date: Oct 2001
Location: London, ON
Posts: 1,492
Likes: 0
Received 0 Likes
on
0 Posts
If its a 13b rotor housing (with stock exhaust port), raise the roof of the exhaust port 5mm and drop the floor 5mm along the curve of the rotor housing face. (BIG D shaped port) What timing does that result in?
#20
If any one is interested in a pair of MFR 12a housings let me know, they have about a 1/4 season on them with no chipping in the top or in the bottom. bolt together 290-310 RWHP. NA
CJG
CJG
#21
Originally Posted by TYSON
If its a 13b rotor housing (with stock exhaust port), raise the roof of the exhaust port 5mm and drop the floor 5mm along the curve of the rotor housing face. (BIG D shaped port) What timing does that result in?
#22
Old [Sch|F]ool
Originally Posted by PDF
Don't drop the bottom of the exhaust port as the earlier opening shortens the power stroke.
But Racing Beat does it, so you, me, and Mazda must be wrong...
Only time I can justify opening the port earlier are for turbo engines that need quicker spoolup, and for nitrous engines that need all the exhaust port they can physically get.
#23
Full Member
Join Date: Nov 2001
Location: california
Posts: 212
Likes: 0
Received 0 Likes
on
0 Posts
PP Housing
My engine builder Pablo out of Pamdale California build custon PP housing using your own housing from turbo to 12A.
I'm getting 292hp at he wheel with a 58mm carb.
cost for the PP is $950 for the PP without the housing.
benoit@realride.com
I'm getting 292hp at he wheel with a 58mm carb.
cost for the PP is $950 for the PP without the housing.
benoit@realride.com
#24
NASA geek
iTrader: (2)
One missconception is loosing "power" from an early opening exhaust port (of corse if you go to extremes [by having a really really big or extremely early open port] throw all this out the window). by the time the rotor has reached the early open exhaust port (lets say a exhaust port opening a streetable 80 degrees BBDC) there is very little moment arm the rotor exerts on the e-shaft (there will be less the 15% torque transfer from peak at this point) so what ever power there is left in the combustion chamer thats still expanding exserts little force in actually making more power at any thing from mid to high rpm. generally you will gain more power by exhausting or expelling the exhaust earlier and gain more power by having less pumping loss and a higher VE then keeping the gases in there longer. It takes an entire system as a whole to make all this work. If you have a tiny turbine or restrictive exhaust of corse this will not work, but who in the quest for power runs restrictive exhaust or small turbine?..LOL
summed up, the early exhaust open gain in hp from a better VE (volumetric effiency) and less pumping loss out weighs the power losses from keeping the still expanding gases in longer in the quest for more power from mid to high rpm verses low rpm torque. Another bonus as someone already stated is in a turbo car a quicker spool up.
~Mike..............
summed up, the early exhaust open gain in hp from a better VE (volumetric effiency) and less pumping loss out weighs the power losses from keeping the still expanding gases in longer in the quest for more power from mid to high rpm verses low rpm torque. Another bonus as someone already stated is in a turbo car a quicker spool up.
~Mike..............
#25
Senior Member
Join Date: Jan 2004
Location: Colorado
Posts: 341
Likes: 0
Received 0 Likes
on
0 Posts
I know this is an old threat
Would you think it is necessary to heat coat the MFR exhaust port for a turbo application? Different to the turbo housing the MFR housings don't have a steel exhaust sleeve being intended for NA use this might not be relevant. Using it for a turbo set-up anyonme knows of applications that run the higher exhaust temps just passed the aluminum without any coating?
Thanks
CW
Thanks
CW