964 vs 993 3.6 motor

[GBX]

I know this has been discussed at length but i was hoping to get some current opinons. For my 964 backdate build, i have the choice of a motor. I love the idea of hydrolic lifters so i dont need to incur the cost of a valve adjustment every 3,000 miles. Is this enough to go with the 993? This car will be build as a weekend or many even daily driver. The car will see very little track time, if any. What motor is more mod friendly? What's going to keep me smiling for years to come??

[Bill Verburg]

Originally Posted by GBX

I know this has been discussed at length but i was hoping to get some current opinons. For my 964 backdate build, i have the choice of a motor. I love the idea of hydrolic lifters so i dont need to incur the cost of a valve adjustment every 3,000 miles. Is this enough to go with the 993? This car will be build as a weekend or many even daily driver. The car will see very little track time, if any. What motor is more mod friendly? What's going to keep me smiling for years to come??

964 and US '95 993 and RoW n/a 993 all use a 55pin OBD1 compliant version of Motronic, 993 versions are slightly upgraded. They all can have their chips swapped easily enough.

If using a relatively stock motor the 993 has a lot of upgrades besides the hyd lifters,
most important being the '95 993 is rated at 272hp/243lb-ft vs 964 250hp/228lb-ft. Even better for street use is a RoW vram 285hp/250ft-lb w/ a much broadened torque curve

[redturbo911]

I was going to tell you read up on my build thread but Bill is very good at this question and he has lots of info. Thanks again Bill.

[Vandit]

Valve adjustment interval is every 15k miles, not 3k.

[GBX]

Originally Posted by Bill Verburg

964 and US '95 993 and RoW n/a 993 all use a 55pin OBD1 compliant version of Motronic, 993 versions are slightly upgraded. They all can have their chips swapped easily enough.

If using a relatively stock motor the 993 has a lot of upgrades besides the hyd lifters,
most important being the '95 993 is rated at 272hp/243lb-ft vs 964 250hp/228lb-ft. Even better for street use is a RoW vram 285hp/250ft-lb w/ a much broadened torque curve

how about a US vram?

[Bill Verburg]

Originally Posted by GBX

how about a US vram?

US vram was available from '96 up, these are all OBD2 and more difficult to work w/, It can be done, it's just harder.

I put a RoW vram which is OBD1 into my '76 and later into my '95 993, I didn't even need to swap the harnesses or DMEs for the last swap just some minor wire changes and swapped chips.

[skinnerd]

Originally Posted by Bill Verburg

If using a relatively stock motor the 993 has a lot of upgrades besides the hyd lifters,
most important being the '95 993 is rated at 272hp/243lb-ft vs 964 250hp/228lb-ft. Even better for street use is a RoW vram 285hp/250ft-lb w/ a much broadened torque curve

With RS cams and intakes, a reflashed ECU and nice sport exhaust you can get 310hp with 371ft-lbs of torque out of the Vram.
What a great engine that still gets really nice MPG when you're just cruising.

[Bill Verburg]

Originally Posted by skinnerd

With RS cams and intakes, a reflashed ECU and nice sport exhaust you can get 310hp with 371ft-lbs of torque out of the Vram.
What a great engine that still gets really nice MPG when you're just cruising.

I know, I have 2 993s that were modified like that, Both have 55pin OBD1 ECUs, one is a US '95 the other a RoW '97, the DMEs can be modified at swapped w/ very little trouble and the chips are socketed so that they are user replaceable, and modified chips to your spec are readily available at a reasonable cost, ~ 1/5 of what a reflash costs.

The issue is that, the US 88pin OBD2 ecus do not have socketed chips, like the 55pin OBD1 cars and so in the case onUS '96 they cannot be modified much because the ECU cannot be reflashed or in the case of the '97 & 98 the ECU can be reflashed but it has to be unsoldered, flashed and then resoldered into it's nest, this is not a job for most people.