964 (mostly) Engine Mods
11-08-2001, 09:44 PM
#1
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964 (mostly) Engine Mods
Since this seems to be a current topic of interest, I thought I'd list the key points from an article by Joel Reiser, of Reiser-Callas Rennsport Racing, which appeared in the 8/99 Panorama, p.37, entitled "Late Model 911 Performance Enhancement".
* Change the chip. Porsche stock chip designed for the lowest common denominator. No specific brand recommendation.
* Change to Carrera Cup airbox - just cut away, or drill holes, in your existing airbox. Supposed to be good for 7 hp. (that doesn't make it to the wheels, according to Jon's dyno test the other day)
* Exhaust - Stock headers not very good, catalytic converter is heavy and restrictive. One alternative is the B&B or Euro headers. Or leave headers on, bypass cat if your state allows it, and replace the final muffler with a bypass pipe. Supposed to be good for around 7 hp. Mentions various combinations due to dual muffler setup. Taking out both mufflers loses hp.
* Recommends, strongly, dynoing the car before embarking on any upgrade regimen. Else put together your own test, ie, time to go in second gear from 3000 to 6000 rpm on level ground in both directions several times. Tony Callas recommends a complete tune-up before starting any upgrades.
* Mass airflow devices - not for street or autocross usage, yes for dedicated track usage, as other upgrades like 3.8L, header/exhaust, larger throttle body, different camshafts, etc, work in concert together.
* Upgrade to 3.8L P&C's
* Cam upgrade, not too wild, however.
* 993 fuel injectors, for a modified engine.
* Unless your engine is a pure race engine, you need to keep some backpressure in the system to get torque and acceleration associated with a powerful engine.
* For early C2/C4's with cast metal intake runners, install the 1992 and later black plastic ones. Smoother inside and save's a wee bit of weight.
* Install the European resonance intake center section.
* If you're going to change the fuel pressure regulator, make sure your fuel hoses aren't cracked anywhere.
* Don't forget to improve brakes when making more power.
* Change the ring and pinion. This moves the gearing down so the car accelerates faster to an ultimately lower top speed. Stock 964's are geared to a top end around 165 mph.
* Install lighter flywheel
* Change the chip again to reflect the lighter flywheel.
* 993 headers adapted to 964 are an excellent way for extra HP. Not a bolt-on due to different flange direction.
* Largest wheel/tire combination they used on the 964 is 9" and 10" wheels with 225 and 275 tires. Caution is that offsets have to be very exact, if off by as little as 3mm, that combination won't work.
* On shock/spring changes, match the shocks and springs, ie, if you have sport shocks use sport lowering springs.
The article goes on to a similar discussion on the 993, a little on the 993TT, and a mention on the 996.
* Change the chip. Porsche stock chip designed for the lowest common denominator. No specific brand recommendation.
* Change to Carrera Cup airbox - just cut away, or drill holes, in your existing airbox. Supposed to be good for 7 hp. (that doesn't make it to the wheels, according to Jon's dyno test the other day)
* Exhaust - Stock headers not very good, catalytic converter is heavy and restrictive. One alternative is the B&B or Euro headers. Or leave headers on, bypass cat if your state allows it, and replace the final muffler with a bypass pipe. Supposed to be good for around 7 hp. Mentions various combinations due to dual muffler setup. Taking out both mufflers loses hp.
* Recommends, strongly, dynoing the car before embarking on any upgrade regimen. Else put together your own test, ie, time to go in second gear from 3000 to 6000 rpm on level ground in both directions several times. Tony Callas recommends a complete tune-up before starting any upgrades.
* Mass airflow devices - not for street or autocross usage, yes for dedicated track usage, as other upgrades like 3.8L, header/exhaust, larger throttle body, different camshafts, etc, work in concert together.
* Upgrade to 3.8L P&C's
* Cam upgrade, not too wild, however.
* 993 fuel injectors, for a modified engine.
* Unless your engine is a pure race engine, you need to keep some backpressure in the system to get torque and acceleration associated with a powerful engine.
* For early C2/C4's with cast metal intake runners, install the 1992 and later black plastic ones. Smoother inside and save's a wee bit of weight.
* Install the European resonance intake center section.
* If you're going to change the fuel pressure regulator, make sure your fuel hoses aren't cracked anywhere.
* Don't forget to improve brakes when making more power.
* Change the ring and pinion. This moves the gearing down so the car accelerates faster to an ultimately lower top speed. Stock 964's are geared to a top end around 165 mph.
* Install lighter flywheel
* Change the chip again to reflect the lighter flywheel.
* 993 headers adapted to 964 are an excellent way for extra HP. Not a bolt-on due to different flange direction.
* Largest wheel/tire combination they used on the 964 is 9" and 10" wheels with 225 and 275 tires. Caution is that offsets have to be very exact, if off by as little as 3mm, that combination won't work.
* On shock/spring changes, match the shocks and springs, ie, if you have sport shocks use sport lowering springs.
The article goes on to a similar discussion on the 993, a little on the 993TT, and a mention on the 996.
11-09-2001, 02:43 AM
#2
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I'm adding my own 2 cents worth with regards to these changes from my own experiences
Originally posted by Bill Gregory:
<STRONG>* Change the chip. Porsche stock chip designed for the lowest common denominator.
</STRONG>I have the Cyntex chip in mine, on Dr Timmins' recommendation
<STRONG>* Change to Carrera Cup airbox - just cut away, or drill holes,
</STRONG>I have a cone filter, and my mechanic doesn't think it flows enough for my engine
<STRONG>* Exhaust - Stock headers not very good,
</STRONG>I have the B&B setup due to limited options. Get used to heavy resonance between 2600 and 3000 RPM. My cats are slip-on, which is a nice feature
<STRONG>* Recommends, strongly, dynoing the car before embarking on any upgrade regimen.
</STRONG>Did it, but my results are meaningless in the face of the other issues I've had. I'll re-dyno when all is said and done to get a real baseline
<STRONG>* Mass airflow devices - not for street or
</STRONG>Maybe down the road some time
<STRONG>* Upgrade to 3.8L P&C's
</STRONG>I was so tempted to do this, since it's apart anyway! I made the decision to have the existing heads and cylinders flycut slightly to true them up. I'm told the 3.8 P/C set is $3800, plus you want to change the cam profile at the same time, ~$300 to get them reground according to my sources.
<STRONG>* Cam upgrade, not too wild, however.
</STRONG>Any specific cam preferences?
<STRONG>* 993 fuel injectors, for a modified engine.
</STRONG>Would make sense on a 3.8
<STRONG>* Unless your engine is a pure race engine, you need to keep some backpressure in the system to get torque and acceleration associated with a powerful engine.
</STRONG>Do the B&B's provide enough back pressure?
<STRONG>* For early C2/C4's with cast metal intake runners, install the 1992 and later black plastic ones. Smoother inside and save's a wee bit of weight.
</STRONG>And the look cool. There was a set on ebay I shoulda grabbed...
<STRONG>* Install the European resonance intake center section.
</STRONG> What is it, what effect does it have, and how do you get one?
<STRONG>* If you're going to change the fuel pressure regulator, make sure your fuel hoses aren't cracked anywhere.
</STRONG>Why would you change this?
<STRONG>* Don't forget to improve brakes when making more power.
</STRONG>I'm adding 930 brakes; fronts are done
<STRONG>* Change the ring and pinion. This moves the gearing down so the car accelerates faster to an ultimately lower top speed.
</STRONG>Eeek! 1st is short enough as it is with my 915! Any shorter and I'd just start in 2nd!
<STRONG>* Install lighter flywheel
</STRONG>Done - Patrick Motorsports 9lb flywheel
<STRONG>* Change the chip again to reflect the lighter flywheel.
</STRONG>Done - came with the program on the Cyntex chip
[qb][/qb]
<STRONG>* Change the chip. Porsche stock chip designed for the lowest common denominator.
</STRONG>I have the Cyntex chip in mine, on Dr Timmins' recommendation
<STRONG>* Change to Carrera Cup airbox - just cut away, or drill holes,
</STRONG>I have a cone filter, and my mechanic doesn't think it flows enough for my engine
<STRONG>* Exhaust - Stock headers not very good,
</STRONG>I have the B&B setup due to limited options. Get used to heavy resonance between 2600 and 3000 RPM. My cats are slip-on, which is a nice feature
<STRONG>* Recommends, strongly, dynoing the car before embarking on any upgrade regimen.
</STRONG>Did it, but my results are meaningless in the face of the other issues I've had. I'll re-dyno when all is said and done to get a real baseline
<STRONG>* Mass airflow devices - not for street or
</STRONG>Maybe down the road some time
<STRONG>* Upgrade to 3.8L P&C's
</STRONG>I was so tempted to do this, since it's apart anyway! I made the decision to have the existing heads and cylinders flycut slightly to true them up. I'm told the 3.8 P/C set is $3800, plus you want to change the cam profile at the same time, ~$300 to get them reground according to my sources.
<STRONG>* Cam upgrade, not too wild, however.
</STRONG>Any specific cam preferences?
<STRONG>* 993 fuel injectors, for a modified engine.
</STRONG>Would make sense on a 3.8
<STRONG>* Unless your engine is a pure race engine, you need to keep some backpressure in the system to get torque and acceleration associated with a powerful engine.
</STRONG>Do the B&B's provide enough back pressure?
<STRONG>* For early C2/C4's with cast metal intake runners, install the 1992 and later black plastic ones. Smoother inside and save's a wee bit of weight.
</STRONG>And the look cool. There was a set on ebay I shoulda grabbed...
<STRONG>* Install the European resonance intake center section.
</STRONG> What is it, what effect does it have, and how do you get one?
<STRONG>* If you're going to change the fuel pressure regulator, make sure your fuel hoses aren't cracked anywhere.
</STRONG>Why would you change this?
<STRONG>* Don't forget to improve brakes when making more power.
</STRONG>I'm adding 930 brakes; fronts are done
<STRONG>* Change the ring and pinion. This moves the gearing down so the car accelerates faster to an ultimately lower top speed.
</STRONG>Eeek! 1st is short enough as it is with my 915! Any shorter and I'd just start in 2nd!
<STRONG>* Install lighter flywheel
</STRONG>Done - Patrick Motorsports 9lb flywheel
<STRONG>* Change the chip again to reflect the lighter flywheel.
</STRONG>Done - came with the program on the Cyntex chip
[qb][/qb]
