New headers/exhaust for the '85/'86 people! Updated with baseline dyno charts.
05-30-2014, 11:33 AM
#63
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Beautiful work! Begs my favorite 928 question ... why did Porsche spend so much money re-doing the 32V engine after just two years of production? At the small production scale of this car, doing a second generation 32V design so soon must have been wildly impractical from a capital investment standpoint. Not to mention forcing Greg to create a different header solution.
Was there something inherently wrong with the 85/86 design that they had to correct?
Was there something inherently wrong with the 85/86 design that they had to correct?
05-30-2014, 11:50 AM
#64
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Beautiful work! Begs my favorite 928 question ... why did Porsche spend so much money re-doing the 32V engine after just two years of production? At the small production scale of this car, doing a second generation 32V design so soon must have been wildly impractical from a capital investment standpoint. Not to mention forcing Greg to create a different header solution.
Was there something inherently wrong with the 85/86 design that they had to correct?
Was there something inherently wrong with the 85/86 design that they had to correct?
The 928 was not alone. Look at all the changes for the 944 line for just the US market:
85.5 - New interior
86 - Turbo
87 - S (for two model years)
87 - Dug up some leftover 924's, shoved the 944 drive-train into it. Called it the "924S" - this was actually a brilliant move for $$.
88 - Turbo S special edition
89 - All Turbo's upgraded to "S" performance
89 - 2.7 base model (for ONE model year)
89 - S2 & Convertible (dropped the turbo)
92 - 968
Compare that to the model changes for the Boxster:
1996 - Introduced
2000 - S & 2.7
2003 - 3.2S
2005 - 987 introduced
This for a car that outsold the 944 and 928 combined which can also "borrow" upgrades from the 911.
Sadly the Porsche that produced the 928 was run by engineers. The Porsche of today is run by accountants (OK, not all bad since Porsche is still in business....)
05-30-2014, 12:48 PM
#65
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Headers look awesome!
Hopefully there'll be some go with that show.
You should get the (default) richer LH chip and adjuster today. (Install PDF) The 'WOTpot' is set for 300 ohms, probably should go to 600 and dial it back.
Re. injector size and headers, it will depend on the AFR. With the S4 FPR, at 6000 rpm with a 12.7-ish AFR the injector rate is around 90%.
You may be able to drop in a 30# and adjust the MAF CO and WOTpot to suit.
The only other dyno tips I can think of at the moment are related to coolant temps.
(Maybe you do these things, but I am always talking to the peeps, too.)
I do sets of two runs only - first is too cold, second is perfect/always best run, third is too hot.
After about 10 sets the engine/exhaust/etc. has stabilized and will produce the most consistent numbers.
Radiator should be cool to the touch before each set of runs.
Turn off the engine but run the S3 aux fan by turning the key to on and ground the (tow pkg) blue wire near the jump post (S4-up just turn on the A/C).
5 mins usually is enough, maybe longer there.
Hopefully there'll be some go with that show.
So, if you have some way to add fuel, it would be great to have it.
I'm trying to do realistic testing, in an unrealistic environment...the dyno....so I'm all ears....trying to learn anything I can learn.
Another question.....do you anticipate that we could run out of fuel with the headers/your chips and need to go to a larger injector?
I'm trying to do realistic testing, in an unrealistic environment...the dyno....so I'm all ears....trying to learn anything I can learn.
Another question.....do you anticipate that we could run out of fuel with the headers/your chips and need to go to a larger injector?
Re. injector size and headers, it will depend on the AFR. With the S4 FPR, at 6000 rpm with a 12.7-ish AFR the injector rate is around 90%.
You may be able to drop in a 30# and adjust the MAF CO and WOTpot to suit.
The only other dyno tips I can think of at the moment are related to coolant temps.
(Maybe you do these things, but I am always talking to the peeps, too.)
I do sets of two runs only - first is too cold, second is perfect/always best run, third is too hot.
After about 10 sets the engine/exhaust/etc. has stabilized and will produce the most consistent numbers.
Radiator should be cool to the touch before each set of runs.
Turn off the engine but run the S3 aux fan by turning the key to on and ground the (tow pkg) blue wire near the jump post (S4-up just turn on the A/C).
5 mins usually is enough, maybe longer there.
06-02-2014, 03:20 PM
#67
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Beautiful work! Begs my favorite 928 question ... why did Porsche spend so much money re-doing the 32V engine after just two years of production? At the small production scale of this car, doing a second generation 32V design so soon must have been wildly impractical from a capital investment standpoint. Not to mention forcing Greg to create a different header solution.
Was there something inherently wrong with the 85/86 design that they had to correct?
Was there something inherently wrong with the 85/86 design that they had to correct?
I believe that once the '85'86 engine was done, Porsche told the engineers that they wanted spark plug access without removal of any of the intake manifold.....and they made some small design changes to the heads, while they were at it.
The two engines have too much in common, for them to be completely separate engineering exercises....they had to have "engineers in common".
__________________
greg brown
714 879 9072
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Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
Free consultations will no longer be available.
Will still be in the shop, isolated and exclusively working on project cars, developmental work and products, engines and transmissions.
Have fun with your 928's people!
greg brown
714 879 9072
GregBBRD@aol.com
Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
Free consultations will no longer be available.
Will still be in the shop, isolated and exclusively working on project cars, developmental work and products, engines and transmissions.
Have fun with your 928's people!
06-02-2014, 03:22 PM
#68
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Headers look awesome!
Hopefully there'll be some go with that show.
You should get the (default) richer LH chip and adjuster today. (Install PDF) The 'WOTpot' is set for 300 ohms, probably should go to 600 and dial it back.
Re. injector size and headers, it will depend on the AFR. With the S4 FPR, at 6000 rpm with a 12.7-ish AFR the injector rate is around 90%.
You may be able to drop in a 30# and adjust the MAF CO and WOTpot to suit.
The only other dyno tips I can think of at the moment are related to coolant temps.
(Maybe you do these things, but I am always talking to the peeps, too.)
I do sets of two runs only - first is too cold, second is perfect/always best run, third is too hot.
After about 10 sets the engine/exhaust/etc. has stabilized and will produce the most consistent numbers.
Radiator should be cool to the touch before each set of runs.
Turn off the engine but run the S3 aux fan by turning the key to on and ground the (tow pkg) blue wire near the jump post (S4-up just turn on the A/C).
5 mins usually is enough, maybe longer there.
Hopefully there'll be some go with that show.
You should get the (default) richer LH chip and adjuster today. (Install PDF) The 'WOTpot' is set for 300 ohms, probably should go to 600 and dial it back.
Re. injector size and headers, it will depend on the AFR. With the S4 FPR, at 6000 rpm with a 12.7-ish AFR the injector rate is around 90%.
You may be able to drop in a 30# and adjust the MAF CO and WOTpot to suit.
The only other dyno tips I can think of at the moment are related to coolant temps.
(Maybe you do these things, but I am always talking to the peeps, too.)
I do sets of two runs only - first is too cold, second is perfect/always best run, third is too hot.
After about 10 sets the engine/exhaust/etc. has stabilized and will produce the most consistent numbers.
Radiator should be cool to the touch before each set of runs.
Turn off the engine but run the S3 aux fan by turning the key to on and ground the (tow pkg) blue wire near the jump post (S4-up just turn on the A/C).
5 mins usually is enough, maybe longer there.
Thanks for your help/suggestions. There's not a day that goes by where I don't learn something about these vehicles....every little bit of information/data helps!
The new pieces arrived, today, thanks. I downloaded the instructions. I'll have Mary read me the directions, if I can't figure it out from the pictures......
Last edited by GregBBRD; 06-02-2014 at 07:13 PM.
06-02-2014, 05:30 PM
#69
06-02-2014, 07:43 PM
#70
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Updated pictures.
Keep in mind that the last pictures were Thursday afternoon and these pictures are on Monday afternoon. Should give you an idea of the time involved in making these things. If anyone is wondering how much of these I do.....I need help figuring out what pipe goes where, which is why they have numbers!
The "stepped design" can be seen much clearer, now that they are welded.
More.
Collector area.
Grant is pretty handy around a TIG machine.
Keep in mind that the last pictures were Thursday afternoon and these pictures are on Monday afternoon. Should give you an idea of the time involved in making these things. If anyone is wondering how much of these I do.....I need help figuring out what pipe goes where, which is why they have numbers!
The "stepped design" can be seen much clearer, now that they are welded.
More.
Collector area.
Grant is pretty handy around a TIG machine.
06-02-2014, 07:48 PM
#71
A real merge collector.
Nice.
Stepped is a great way to get bigger pipe where you need it.
Nice.
Stepped is a great way to get bigger pipe where you need it.
06-02-2014, 08:57 PM
#72
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Like almost everything, in the automotive world, there's a group of people that swear by a stepped header and a group of people that swear at a stepped header. I can swear that I don't know.
Once you consider the port size, the collector size, the exhaust pipe size, the exiting velocity, the expanding gasses, the terrible firing order problems of the 928 engine, and the anti-reversion effect.....
All one can do is some math and give it a try.
Once you consider the port size, the collector size, the exhaust pipe size, the exiting velocity, the expanding gasses, the terrible firing order problems of the 928 engine, and the anti-reversion effect.....
All one can do is some math and give it a try.
06-02-2014, 11:50 PM
#73
Firing order problems?
