Toyota MR2 Message Board - View Single Post

MR-Fixer · 03-09-2006, 01:34 AM

So I did something incredibly stupid and ruined my stock supercharger on my 4agze equipped 87 Mk I. I will never admit exactly what I did.

The supply of SC12 superchargers on Ebay sort of dried up the last several months. One nice specimen went for next to $500.! So I decided to upgrade to the Ogura made SC!4 which varies from the 15% smaller capacity SC12. The 14 unit is just under two inches longer. But has the same height and width and pulley position. Its almost a no brainer except the inlet and outlet tubes and mounting hardware are all completely and totally wrong for an MR2. In addition to the larger compressor capacity, I noticed that the pulley on the 14 is 1.25 inches less in circumference that the USDM SC12 pulley. What that means is the SC14 will spin at 7500 RPMs, and give the same engine RPM, the SC12 would turn at 6900 RPMs.

So between a faster spinning Supercharger, and increased capacity for compression, I will need to make some changes to keep the engine from detonating from a lean mixture. When I say detonating, I really mean in Hole-in-Piston-itus.

So far, I've definitely decided to install a Two Stage water alcohol injection system. Purchase some Supra 7mgte 440 CC injectors, and possibly install a Rising Rate Fuel Pressure regulator.

Comments, encouragement, opinions, and advice are welcome.

03-09-2006, 01:34 AM	#1 (permalink)
MR-Fixer Censored *** censors Join Date: Feb 2006 Location: Censored Posts: 95 Thanks: 0 Thanked 1 Time in 1 Post iTrader Rating: (0/0%** )	SC14 Upgrade in Progress So I did something incredibly stupid and ruined my stock supercharger on my 4agze equipped 87 Mk I. I will never admit exactly what I did. The supply of SC12 superchargers on Ebay sort of dried up the last several months. One nice specimen went for next to $500.! So I decided to upgrade to the Ogura made SC!4 which varies from the 15% smaller capacity SC12. The 14 unit is just under two inches longer. But has the same height and width and pulley position. Its almost a no brainer except the inlet and outlet tubes and mounting hardware are all completely and totally wrong for an MR2. In addition to the larger compressor capacity, I noticed that the pulley on the 14 is 1.25 inches less in circumference that the USDM SC12 pulley. What that means is the SC14 will spin at 7500 RPMs, and give the same engine RPM, the SC12 would turn at 6900 RPMs. So between a faster spinning Supercharger, and increased capacity for compression, I will need to make some changes to keep the engine from detonating from a lean mixture. When I say detonating, I really mean in Hole-in-Piston-itus. So far, I've definitely decided to install a Two Stage water alcohol injection system. Purchase some Supra 7mgte 440 CC injectors, and possibly install a Rising Rate Fuel Pressure regulator. Comments, encouragement, opinions, and advice are welcome.