Toyota MR2 Message Board - View Single Post

keithlee21 · 03-05-2005, 10:58 AM

It seems to me that everyone seems to think the Gen3 difference comes down to money. Let's face it! Yes, it is more expensive. But, lets also realize there are many differences between the generations:

Gen III Differences
- MAP sensor instead of AFM
- Bosch D-Jetronic (Gen III) vs. L-Jetronic (relatively primitive) engine management
- CT20b turbo replaces CT26
- Boost raised from 10psi to 13psi
- Fuel cut raised from 12 psi to 18 psi
- Different ECU
- 4 wire O2 sensor
- Shim under bucket valve shims
- slightly more aggressive cams
- Revised internals (pistons, con-rods etc.)
- Revised cylinder head cooling passages/water jackets
- Revised intake manifold (8 'independent long ports' reduced to 4)
- intake manifold inlet air temperature sensor added. i.e. after turbo and intercooler.
- Revised gearbox with close ratio gearing
- lower compression ratio
- stainless steel head gasket
- factory 540cc injectors replace 430cc injectors
- revised fuel rail with bigger bore and relocated pressure regulator
- TVIS eliminated
- EGR eliminated
- LSD in 80% of them
- throttle body increased from 55mm to 60mm
- inlet valve lift increased from 8.2 to 8.7
- intake manifold inlet air temperature sensor added
- Less restrictive exhaust elbow
- Aluminum oil pan
- more rigid alloy sump and additional oil baffles
- Factory Catch can
- Better Oil Cooler and relocated oil filter (bottom)
- 4 Channel ABS coupled with Traction Control available
- No. 1 compression ring described as 'stainless steel' instead of just 'steel'. Oil ring is described as 'stainless steel' instead of 'a combination of steel and stainless steel'.
- The fuel pressure raised from 36 PSI (2.55 bar) to 41 PSI (2.9bar).

If you notice many of these changes are being made by owners to their USDM engines. I see many owners putting on aftermarket boost controllers, putting on different intake manifolds, boring out their throttle bodies, etc...But, I am a huge believer in stock Toyota OEM quality and, I like the fitment and quality of a stock part rather than an aftermarket one.

But, as for money being the main subject for debate. If you can afford it then you have the option. We all know that it is very possible to make your car more powerful, cheaper with the USDM engine. But, would you also say that the Gen3 has the same or more capabilities to make power as the USDM engine? If you want the cheapest way to make power then I would suggest to stay with the USDM engine. But, if you are investing into your vehicle for the long run then I would suggest to keep the Gen3 in mind as an option for powerplant to go with.

But, most of all...regardless, of which engine you decide on please DO NOT NEGLECT TUNING!

03-05-2005, 10:58 AM	#23 (permalink)
keithlee21 No Skills Join Date: Feb 2005 Posts: 4 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	It seems to me that everyone seems to think the Gen3 difference comes down to money. Let's face it! Yes, it is more expensive. But, lets also realize there are many differences between the generations: Gen III Differences - MAP sensor instead of AFM - Bosch D-Jetronic (Gen III) vs. L-Jetronic (relatively primitive) engine management - CT20b turbo replaces CT26 - Boost raised from 10psi to 13psi - Fuel cut raised from 12 psi to 18 psi - Different ECU - 4 wire O2 sensor - Shim under bucket valve shims - slightly more aggressive cams - Revised internals (pistons, con-rods etc.) - Revised cylinder head cooling passages/water jackets - Revised intake manifold (8 'independent long ports' reduced to 4) - intake manifold inlet air temperature sensor added. i.e. after turbo and intercooler. - Revised gearbox with close ratio gearing - lower compression ratio - stainless steel head gasket - factory 540cc injectors replace 430cc injectors - revised fuel rail with bigger bore and relocated pressure regulator - TVIS eliminated - EGR eliminated - LSD in 80% of them - throttle body increased from 55mm to 60mm - inlet valve lift increased from 8.2 to 8.7 - intake manifold inlet air temperature sensor added - Less restrictive exhaust elbow - Aluminum oil pan - more rigid alloy sump and additional oil baffles - Factory Catch can - Better Oil Cooler and relocated oil filter (bottom) - 4 Channel ABS coupled with Traction Control available - No. 1 compression ring described as 'stainless steel' instead of just 'steel'. Oil ring is described as 'stainless steel' instead of 'a combination of steel and stainless steel'. - The fuel pressure raised from 36 PSI (2.55 bar) to 41 PSI (2.9bar). If you notice many of these changes are being made by owners to their USDM engines. I see many owners putting on aftermarket boost controllers, putting on different intake manifolds, boring out their throttle bodies, etc...But, I am a huge believer in stock Toyota OEM quality and, I like the fitment and quality of a stock part rather than an aftermarket one. But, as for money being the main subject for debate. If you can afford it then you have the option. We all know that it is very possible to make your car more powerful, cheaper with the USDM engine. But, would you also say that the Gen3 has the same or more capabilities to make power as the USDM engine? If you want the cheapest way to make power then I would suggest to stay with the USDM engine. But, if you are investing into your vehicle for the long run then I would suggest to keep the Gen3 in mind as an option for powerplant to go with. But, most of all...regardless, of which engine you decide on please DO NOT NEGLECT TUNING!