89 930 CIS or Motronic?
09-30-2002, 11:43 AM
#1
Advanced
Thread Starter
89 930 CIS or Motronic?
Is an 89' 930 motronic or cis? It seems that the fact the 89c4 came out the same year, books aren't clear on wether they are talking about the C4 or the carreras. Would the 930 benefit from SSI's?
Regards,
Dallas
Regards,
Dallas
09-30-2002, 03:49 PM
#4
RL Technical Advisor
Hi Dallas:
The reason why Porsche didn't use Motronic on Turbos was cost. These were always sold in far fewer units than 911's, and they simply didn't want to spend the $$$$ to develop an intake system and map these cars. Both are very large investments. For the power range that these cars are the most durable in, its no disadvantage.
SSI does not make anything for Turbos however, installing a set of B&B or GHL header/mufflers really makes a big difference in reducing boost lag and adds more power. Its quite worthwhile!
The reason why Porsche didn't use Motronic on Turbos was cost. These were always sold in far fewer units than 911's, and they simply didn't want to spend the $$$$ to develop an intake system and map these cars. Both are very large investments. For the power range that these cars are the most durable in, its no disadvantage.
SSI does not make anything for Turbos however, installing a set of B&B or GHL header/mufflers really makes a big difference in reducing boost lag and adds more power. Its quite worthwhile!
09-30-2002, 03:59 PM
#5
[quote] installing a set of B&B or GHL header/mufflers really makes a big difference in reducing boost lag and adds more power. Its quite worthwhile!
<hr></blockquote>
Steve, how much of a decrease in lag would I expect by putting on headers? I currently run stock heat exchangers w/ a euro muffler and a K27 on my '87 930. I've heard people say that boost will come on at around 2k rpm with headers, but I have a hard time believing that.
I was thinking that a surefire way to decrease lag time is through SC cams and a 3.4 upgrade; lag time being decreased because the car will climb through 1k-3k rpm range a lot quicker due to the increased displacement, bump in compression, and cams helping down low. Naturally, these mods will costt some $$$, and I was wondering if adding the B&B headers to these already significant costs would be worth it. What do you think?
<hr></blockquote>
Steve, how much of a decrease in lag would I expect by putting on headers? I currently run stock heat exchangers w/ a euro muffler and a K27 on my '87 930. I've heard people say that boost will come on at around 2k rpm with headers, but I have a hard time believing that.
I was thinking that a surefire way to decrease lag time is through SC cams and a 3.4 upgrade; lag time being decreased because the car will climb through 1k-3k rpm range a lot quicker due to the increased displacement, bump in compression, and cams helping down low. Naturally, these mods will costt some $$$, and I was wondering if adding the B&B headers to these already significant costs would be worth it. What do you think?
09-30-2002, 04:16 PM
#6
Nordschleife Master
Dallas,
I wish Porsche had gone with a Motronic setup on the earlier turbos as well. I've installed an aftermarket EFI setup which uses much of the 3.2 Carrera intake system and removes ALL of the CIS hoses, lines, etc. It is much nicer, cleaner, and tunable. Putting a set of GHL or B&B heat exhangers(headers) on with a good quality muffler will definately help with your lag problem. Of course 3.4 P&C and cams is the hot setup along with a larger turbo and intercooler.
I wish Porsche had gone with a Motronic setup on the earlier turbos as well. I've installed an aftermarket EFI setup which uses much of the 3.2 Carrera intake system and removes ALL of the CIS hoses, lines, etc. It is much nicer, cleaner, and tunable. Putting a set of GHL or B&B heat exhangers(headers) on with a good quality muffler will definately help with your lag problem. Of course 3.4 P&C and cams is the hot setup along with a larger turbo and intercooler.
09-30-2002, 05:16 PM
#7
RL Technical Advisor
[quote]Originally posted by t.p.:
<strong>
Steve, how much of a decrease in lag would I expect by putting on headers? I currently run stock heat exchangers w/ a euro muffler and a K27 on my '87 930. I've heard people say that boost will come on at around 2k rpm with headers, but I have a hard time believing that.
I was thinking that a surefire way to decrease lag time is through SC cams and a 3.4 upgrade; lag time being decreased because the car will climb through 1k-3k rpm range a lot quicker due to the increased displacement, bump in compression, and cams helping down low. Naturally, these mods will costt some $$$, and I was wondering if adding the B&B headers to these already significant costs would be worth it. What do you think?</strong><hr></blockquote>
T.P,....
All things being equal, installing these header/muffler systems does bring the boost in almost 1000 RPM sooner but there are mitigating factors at work here, too. Engine health plays big roles here since static compression also plays a large part in determining how much off-boost torque these engines can produce.
I can tell you that this modification is THE very first thing we recommend to all Turbo owner who are starting down the path of performance improvements and provides the foundation for what follows.
The real issue with any Turbo is not that they do not have enough power, its the KIND of power that they make, combined with poor gearing, that people find very frustrating. What people need is usuable power; the kind that makes thrust anytime the throttle is opened up and to accomplish that, an increase in displacement and static compression ratio is necessary.
As Geoff correctly pointed out, installing the 3.4 litre kit with its 7.5:1 CR, really makes a huge difference. FWIW, our 3.4 litre, twin-plugged SC-cammed Turbo engines make over 300 lb-ft of torque at 3000,.....
Together with better gearing (do NOT underestimate how much improvement this makes), these cars are very drivable and have excellent throttle response.
<strong>
Steve, how much of a decrease in lag would I expect by putting on headers? I currently run stock heat exchangers w/ a euro muffler and a K27 on my '87 930. I've heard people say that boost will come on at around 2k rpm with headers, but I have a hard time believing that.
I was thinking that a surefire way to decrease lag time is through SC cams and a 3.4 upgrade; lag time being decreased because the car will climb through 1k-3k rpm range a lot quicker due to the increased displacement, bump in compression, and cams helping down low. Naturally, these mods will costt some $$$, and I was wondering if adding the B&B headers to these already significant costs would be worth it. What do you think?</strong><hr></blockquote>
T.P,....
All things being equal, installing these header/muffler systems does bring the boost in almost 1000 RPM sooner but there are mitigating factors at work here, too. Engine health plays big roles here since static compression also plays a large part in determining how much off-boost torque these engines can produce.
I can tell you that this modification is THE very first thing we recommend to all Turbo owner who are starting down the path of performance improvements and provides the foundation for what follows.
The real issue with any Turbo is not that they do not have enough power, its the KIND of power that they make, combined with poor gearing, that people find very frustrating. What people need is usuable power; the kind that makes thrust anytime the throttle is opened up and to accomplish that, an increase in displacement and static compression ratio is necessary.
As Geoff correctly pointed out, installing the 3.4 litre kit with its 7.5:1 CR, really makes a huge difference. FWIW, our 3.4 litre, twin-plugged SC-cammed Turbo engines make over 300 lb-ft of torque at 3000,.....
Together with better gearing (do NOT underestimate how much improvement this makes), these cars are very drivable and have excellent throttle response.
Trending Topics
09-30-2002, 08:31 PM
#8
[quote] All things being equal, installing these header/muffler systems does bring the boost in almost 1000 RPM sooner <hr></blockquote>
Steve:
I have a practically new porsche euro muffler which I've heard from many is of better quality than the B&B's. Would this muffler be compatible with the B&B headers? Also, I cannot recall when boost came on with my stock muffler/catalytic converter set-up (didn't have it on for too long). Does replacing the U.S. style exhaust with the euro one (while keeping the stock heat exchangers) improve lag?
LBNL, how do you do the dual ignition now that RSR distributor caps are gone? Electromotive? Doesn't seem cost-effective if one keeps the boost at .8.
Steve:
I have a practically new porsche euro muffler which I've heard from many is of better quality than the B&B's. Would this muffler be compatible with the B&B headers? Also, I cannot recall when boost came on with my stock muffler/catalytic converter set-up (didn't have it on for too long). Does replacing the U.S. style exhaust with the euro one (while keeping the stock heat exchangers) improve lag?
LBNL, how do you do the dual ignition now that RSR distributor caps are gone? Electromotive? Doesn't seem cost-effective if one keeps the boost at .8.
09-30-2002, 10:26 PM
#9
RL Technical Advisor
[quote]Originally posted by t.p.:
<strong>
Steve:
I have a practically new porsche euro muffler which I've heard from many is of better quality than the B&B's. Would this muffler be compatible with the B&B headers? Also, I cannot recall when boost came on with my stock muffler/catalytic converter set-up (didn't have it on for too long). Does replacing the U.S. style exhaust with the euro one (while keeping the stock heat exchangers) improve lag?
LBNL, how do you do the dual ignition now that RSR distributor caps are gone? Electromotive? Doesn't seem cost-effective if one keeps the boost at .8.</strong><hr></blockquote>
TP:
There is no question that B&B stuff is not the same quality as Factory pieces, however we use these systems due to the huge performance increase that they provide. You cannot use a Factory muffler with the B&B (or GHL) system as their mounting positions are incompatible. Its one OR the other, in their entirety. In my experiences, I've not found any Factory street turbo exhaust system to make the same improvement in boost lag or HP as these aftermarket ones.
On the subject of effective Twin-ignition for Turbos,......I'm working on another alternative to the discontinued Bosch RSR caps & rotors and when I've secured that, I'd be happy to let you know.
Twin-ignition should not be judged simply on the merits of cost effectiveness, this should be classified under heading; Survival, as its really integral toward ensuring engine life using pump gas in this country. Certainly there are performance and drivability benefits that cannot be overlooked, but the poor state of pump gasoline really define the reasons for installing this very important upgrade.
<strong>
Steve:
I have a practically new porsche euro muffler which I've heard from many is of better quality than the B&B's. Would this muffler be compatible with the B&B headers? Also, I cannot recall when boost came on with my stock muffler/catalytic converter set-up (didn't have it on for too long). Does replacing the U.S. style exhaust with the euro one (while keeping the stock heat exchangers) improve lag?
LBNL, how do you do the dual ignition now that RSR distributor caps are gone? Electromotive? Doesn't seem cost-effective if one keeps the boost at .8.</strong><hr></blockquote>
TP:
There is no question that B&B stuff is not the same quality as Factory pieces, however we use these systems due to the huge performance increase that they provide. You cannot use a Factory muffler with the B&B (or GHL) system as their mounting positions are incompatible. Its one OR the other, in their entirety. In my experiences, I've not found any Factory street turbo exhaust system to make the same improvement in boost lag or HP as these aftermarket ones.
On the subject of effective Twin-ignition for Turbos,......I'm working on another alternative to the discontinued Bosch RSR caps & rotors and when I've secured that, I'd be happy to let you know.
Twin-ignition should not be judged simply on the merits of cost effectiveness, this should be classified under heading; Survival, as its really integral toward ensuring engine life using pump gas in this country. Certainly there are performance and drivability benefits that cannot be overlooked, but the poor state of pump gasoline really define the reasons for installing this very important upgrade.
10-01-2002, 03:05 PM
#10
[quote] Twin-ignition should not be judged simply on the merits of cost effectiveness, this should be classified under heading; Survival, as its really integral toward ensuring engine life using pump gas in this country. Certainly there are performance and drivability benefits that cannot be overlooked, but the poor state of pump gasoline really define the reasons for installing this very important upgrade. <hr></blockquote>
Steve,
Would you strongly recommend twin-ignition w/ just .8 bar? I know that gas sucks and all, but I know of many people running 1.0 and above w/ single ignition and no reported probs. I wouldn't go there w/o twin-ignition; I'd rather stick at .8 and single ignition for cost reasons/engine longetivity.
Steve,
Would you strongly recommend twin-ignition w/ just .8 bar? I know that gas sucks and all, but I know of many people running 1.0 and above w/ single ignition and no reported probs. I wouldn't go there w/o twin-ignition; I'd rather stick at .8 and single ignition for cost reasons/engine longetivity.
10-01-2002, 09:38 PM
#11
RL Technical Advisor
[quote]Originally posted by t.p.:
<strong>
Steve,
Would you strongly recommend twin-ignition w/ just .8 bar? I know that gas sucks and all, but I know of many people running 1.0 and above w/ single ignition and no reported probs. I wouldn't go there w/o twin-ignition; I'd rather stick at .8 and single ignition for cost reasons/engine longetivity.</strong><hr></blockquote>
TP:
Based on the sorry state of pump gas, I would use twin-ignition on all Turbos. I've heard detonation on bone-stock 930's using 92 octane fuel in hot weather that would be aleviated with dual plug operation.......
The operative word in your paragraph is "reported problems". I've taken apart so many Turbo engines since 1978 that have suffered broken rings that has forced me to make this recommendation. Non of these owners ever reported any problems nor heard a thing.
Fact is, these engines are so noisy that you will never really hear the sub-audible detonation that shatters rings and damages piston ring lands. If you ever hear the engine knocking (detonating) under acceleration, the damage is being done VERY quickly and its imperative that you lift off the throttle immediately. Turbocharged engines do not have any margin under these conditions.
Twin-ignition lowers an engine's octane requirements by the equivalent of 1 point of compression. For owners of 930's who are contemplating some upgrades, this means that you have a margin for a little more boost (1 bar max), a little more compression (8:1 max) and a little more margin in hot weather when cylinder temperatures reach their peak.
Remember, these engines in stock form were designed, configured, and intended for Europe's 98 RON (94 R+M/2) fuels. Its marginal on 92, much less 91. If you live where 94 octane pump gas is available, you can retain the stock configuration and not have an issue.
Given the costs of replacing P/C's and the associated labor, its my opinion that installing twin-ignition at overhaul time is cost-effective in the long run.
<strong>
Steve,
Would you strongly recommend twin-ignition w/ just .8 bar? I know that gas sucks and all, but I know of many people running 1.0 and above w/ single ignition and no reported probs. I wouldn't go there w/o twin-ignition; I'd rather stick at .8 and single ignition for cost reasons/engine longetivity.</strong><hr></blockquote>
TP:
Based on the sorry state of pump gas, I would use twin-ignition on all Turbos. I've heard detonation on bone-stock 930's using 92 octane fuel in hot weather that would be aleviated with dual plug operation.......
The operative word in your paragraph is "reported problems". I've taken apart so many Turbo engines since 1978 that have suffered broken rings that has forced me to make this recommendation. Non of these owners ever reported any problems nor heard a thing.
Fact is, these engines are so noisy that you will never really hear the sub-audible detonation that shatters rings and damages piston ring lands. If you ever hear the engine knocking (detonating) under acceleration, the damage is being done VERY quickly and its imperative that you lift off the throttle immediately. Turbocharged engines do not have any margin under these conditions.
Twin-ignition lowers an engine's octane requirements by the equivalent of 1 point of compression. For owners of 930's who are contemplating some upgrades, this means that you have a margin for a little more boost (1 bar max), a little more compression (8:1 max) and a little more margin in hot weather when cylinder temperatures reach their peak.
Remember, these engines in stock form were designed, configured, and intended for Europe's 98 RON (94 R+M/2) fuels. Its marginal on 92, much less 91. If you live where 94 octane pump gas is available, you can retain the stock configuration and not have an issue.
Given the costs of replacing P/C's and the associated labor, its my opinion that installing twin-ignition at overhaul time is cost-effective in the long run.
10-01-2002, 09:47 PM
#12
Nordschleife Master
Join Date: Oct 2001
Location: Mount Pleasant, South Carolina
Posts: 7,568
Likes: 0
Received 5 Likes
on
3 Posts
For around town driving and occasional boosting at 1 bar, is 93 octane OK? On the track, I use nothing but 100 octane at 1 bar.
BTW. I was talking to my buddy today about detonation. We both know what it is and what it sounds like, but I've never heard it on my car (I think), on the street or on the track. On the track, with all the wind noise, helmet, open exhaust, wastegate dump pipe, etc. it would have to be pretty severe to hear I would think. Does it sound just like a V8 under load with pinging, etc? Thoughts?
Jim
BTW. I was talking to my buddy today about detonation. We both know what it is and what it sounds like, but I've never heard it on my car (I think), on the street or on the track. On the track, with all the wind noise, helmet, open exhaust, wastegate dump pipe, etc. it would have to be pretty severe to hear I would think. Does it sound just like a V8 under load with pinging, etc? Thoughts?
Jim
10-02-2002, 04:11 AM
#13
RL Technical Advisor
Hi Jim:
As long as you are not on-boost long, 93 will be OK. Short bursts will not hurt anything but I'd be careful when its hot outside at 1 bar; .8 is safer.
Detonation sounds pretty much the same in a Porsche as in a Chevy, but as you wisely pointed out, the background mechanical & environment noise will block all but the worst cases and that is what makes this soooo dangerous.
Human ears make terrible and ineffective knock sensors,....
As long as you are not on-boost long, 93 will be OK. Short bursts will not hurt anything but I'd be careful when its hot outside at 1 bar; .8 is safer.
Detonation sounds pretty much the same in a Porsche as in a Chevy, but as you wisely pointed out, the background mechanical & environment noise will block all but the worst cases and that is what makes this soooo dangerous.
Human ears make terrible and ineffective knock sensors,....
10-02-2002, 09:43 PM
#14
Nordschleife Master
Join Date: Oct 2001
Location: Mount Pleasant, South Carolina
Posts: 7,568
Likes: 0
Received 5 Likes
on
3 Posts
Steve,
I've read about some DIY knock sensors that one can build, similar to later model factory turbos, but they would not adjust anything, just flash a light to warn you. My understanding it that there is too much "engine noise" with the chains and all to install/retro one on an '87 style 930. Any ideas?
My buddy built a 40 LED wide band O2 sensor that's dead on for about $150 or so. A lot less than a Snap On or Mac I would imagine. Now I'm trying to get him to build me one since I'm not a EE.
Jim
I've read about some DIY knock sensors that one can build, similar to later model factory turbos, but they would not adjust anything, just flash a light to warn you. My understanding it that there is too much "engine noise" with the chains and all to install/retro one on an '87 style 930. Any ideas?
My buddy built a 40 LED wide band O2 sensor that's dead on for about $150 or so. A lot less than a Snap On or Mac I would imagine. Now I'm trying to get him to build me one since I'm not a EE.
Jim
10-03-2002, 05:21 AM
#15
RL Technical Advisor
[quote]Originally posted by Jim Bell:
<strong>Steve,
I've read about some DIY knock sensors that one can build, similar to later model factory turbos, but they would not adjust anything, just flash a light to warn you. My understanding it that there is too much "engine noise" with the chains and all to install/retro one on an '87 style 930. Any ideas?
My buddy built a 40 LED wide band O2 sensor that's dead on for about $150 or so. A lot less than a Snap On or Mac I would imagine. Now I'm trying to get him to build me one since I'm not a EE.
Jim</strong><hr></blockquote>
Hi Jim:
There are several serious issues about aftermarket knock sensors,...1) Mounting position for these air-cooled engines, (2) Knock-sensor programming; tuning the piezo-electric sensor to the range of frequencies given off by these engines when they detonate.
IMHO, neither one can be addressed by these aftermarket offerings that are suited for V-8 cars. Porsche spent a lot of R&D monies to develop this feature and the cars that are equipped, can and will reduce timing in the offending cylinder(s), not all 6 at once.
In short, its simply not feasible to do this on Turbos and this why I've recommended twin-ignition for Turbos as part of dealing with this, proactively.
<strong>Steve,
I've read about some DIY knock sensors that one can build, similar to later model factory turbos, but they would not adjust anything, just flash a light to warn you. My understanding it that there is too much "engine noise" with the chains and all to install/retro one on an '87 style 930. Any ideas?
My buddy built a 40 LED wide band O2 sensor that's dead on for about $150 or so. A lot less than a Snap On or Mac I would imagine. Now I'm trying to get him to build me one since I'm not a EE.
Jim</strong><hr></blockquote>
Hi Jim:
There are several serious issues about aftermarket knock sensors,...1) Mounting position for these air-cooled engines, (2) Knock-sensor programming; tuning the piezo-electric sensor to the range of frequencies given off by these engines when they detonate.
IMHO, neither one can be addressed by these aftermarket offerings that are suited for V-8 cars. Porsche spent a lot of R&D monies to develop this feature and the cars that are equipped, can and will reduce timing in the offending cylinder(s), not all 6 at once.
In short, its simply not feasible to do this on Turbos and this why I've recommended twin-ignition for Turbos as part of dealing with this, proactively.