Hopefully I'm not telling anyone to suck eggs here....
Ok....So I've been looking at whether the IHI blower would
do 'da bidness in regards to pumping up a 3.7L M112 E37 such as you'd find in this
SLK350.....or as I've covered already - the ML350 circa 2003-5 dropped into an SRT-6 or SLK32...or even a C32 for that mater.
Well - many thanks to Boostmonkey and Grip Grip for their data, so I had to look at the capacity of our current IHI blower. If you've read the previous posts, a Kleemann was added to the one in Taiwan. But I wanted to look at a simply "block swap" of the E37 with the E32.
Well....I'm pretty happy with the changes/improvements I've made to my model as a result of Boostmonkeys posted data here;
https://www.crossfireforum.org/forum...k-pulleys.html
As a result of this work I know the
volume output of the IHI is around 1.6L/rev at 13-15,000rpm. I also mentioned the principal at work here....(no
boasting intended) - the SC pumps so much air in ....the cylinders have to take it away...if they cant, the pressure increases in the plenum until they can. Simple?...hope so.
Just a note on engine capacity. Although our motors are a 3.2L, the actual volume including the "clearance volume" above the top of the cylinder for 9:1 compression is 3.60L. Likewise with an E37 with a compression ratio of 10:1 the total capacity is 4.12L - or a difference of +16%.
So when you go from a 3.2L capacity E32 engine and wack in a 3.7L E37....suddenly the engine can "take away" 16% more volume each cycle....so what happens to the plenum pressure for the same SC speed ...it drops. What does this do to horse power?....more air + lower pressure....has the total mass of feed air increased??? Because if air has increased...for a set 12AFR...that means more fuel = hopefully more hp.
So I ran some numbers through my model....
---I've assumed stock air intake setup at 448cfm for 15"WG
---At 6000rpm
---a 50C (122F) post IC intake temp
---which requires the cooler to extract about 10kW (34k BTU's/hr) of heat from the charge.
---Tranny loss = 18%
---Sea Level
---SC eff. locked at 65%.
......Setup........
Engine.....Pulleys.......MAP........IAT........... .additional.................intake air
............................psi..........degF..... .cooling required (kBTU/hr)....cfm........rwhp
E32.........74/155......12.8.......122..............0.(0)........ ...............636........290
E32.........62/155......20.1.......122............14.(48)........ ..............805........341
E37.........74/155.......9.1.........95..............0.(0)....... ................658........306
E37.........65/155......13.6.......122..............3.(10)....... ..............749.........333
E37.........62/155......15.4.......122..............7.(23)....... ..............798.........347
short story long....
the bigger E37 block will run a comparitively lower pressure for the same rwhp
That's probably a good thing given the 10:1 compression. The compression could possibly be lowered back to 9:1 by adding roughly 0.0046" (1.2mm) to the deck height. This only reduces rwhp by 1hp.
As a result intake temps are lower and the whole environment is better.
Because the SC pressure ratio is down, the SC is operating in a better zone and this may afford another 5-7rwhp and we're not pushing the SC into realms past where the current E32+62/155 guys are upto.
If you're feeling really adventurous - some
fantasy numbers
......Setup........
Engine.....Pulleys.......MAP........IAT........... .additional.................intake air
............................psi..........degF..... .cooling required (kBTU/hr)....cfm........rwhp
E32.........62/178......20.9........122...........20.( 68)......................955........392
E37.........62/178......27.1........122...........30.(137)....... ..............966........384
Probably need to redo with SC eff. in as well as this is right out there. 32Krazy indicated the SC was running out of legs in a 65/178 >6200rpm stacked setup
I still need to look at the bottom end of the E37.
I also still need to look at the cam setup, but that doesnt hold as much worry much any more as swaping over I' ve discovered isnt as bigger deal as I first thought.
b22b