Euro S.
06-13-2003, 06:39 PM
#1
Nordschleife Master
Thread Starter
Euro S.
What kind of a diffrence does a EuroS cam make to the US S engine?
I've often read about what it would do to a US car, but exactly what would it do? Any testimonials out there?
The reason I ask is I've been looking at what made the EuroS make so much more power than the US S. The exaust and compression wheren't that much better. The valve's size wsa the same. The ignition system was the exact same. What the intake and fuel control on the Euro S the same as the Euro of the same year?
Thank you
I've often read about what it would do to a US car, but exactly what would it do? Any testimonials out there?
The reason I ask is I've been looking at what made the EuroS make so much more power than the US S. The exaust and compression wheren't that much better. The valve's size wsa the same. The ignition system was the exact same. What the intake and fuel control on the Euro S the same as the Euro of the same year?
Thank you
06-13-2003, 07:51 PM
#2
Drifting
cant answer your question really but i can say (and it may not be so apparent to y'all in the usa) that there isnt too much difference between a stock s2 euro and a stock gt, on the road - IMO!
i guess what im saying is that tuning an american market engine to euro spec could be a worthwhile thing to do as an upgrade, if you can find the parts!
i guess what im saying is that tuning an american market engine to euro spec could be a worthwhile thing to do as an upgrade, if you can find the parts!
06-13-2003, 08:51 PM
#3
Addict
Rennlist Member
Rennlist Member
... note, this post is unaided by the use of avitars ....
The exaust and compression wheren't that much better.
>> Compression is a major contribution to power. If more air (oxygen) and fuel are compressed, more power is produced. This is why superchargers and turbochargers add power.
The valve's size was the same.
>> Wrong, the Euro S has larger valves (same size as 944s, the 928 CIS and L-Jet engine's valves are actually smaller than the 944!). The intake tubes on the Euro S motor are larger, the throttle housing is about 3.25 inch in diameter vs. 2.5 inch for the 928 CIS and L-jet engine. Better breathing, larger valves, higher compression = more HP.
The ignition system was the exact same.
>> Only from '80 - 83 was the same ignition used. The Euro S from '84 - 86 used EZK and a dual cap distributor (4 plug wire each) borrowed from the two plug per cylinder 3.6 liter 911s.
>> Euro S cams were more radical, the low-end power was less but after 3K RPM the power really kicks in. So, in town driving you won't feel much difference unless you really wind it up. If you put Euro S cams on an unchanged US engine, you probably wouldn't get that much more power due to the more restrictive intake and lower compression.
What the intake and fuel control on the Euro S the same as the Euro of the same year?
>> From '80 - '83 they were both CIS K-Jetronic (only used in the US market from '78 to '79). LH-Jetronic was used from '84 onwards. The US didn't see LH untill '85 with the advent of the 32 valve engine (that was still rated at less HP than the 16 valve Euro motor).
The Euro S motor wasn't spec'd to pass US emissions. A little known fact, in '85 and '86, Germany and other European countries were starting to provide tax incentives for the purchase of optional catalytic converters. A cat equipped 928 Euro in '85 or '86 used the 32 valve US motor.
While we read about listers removing cats from their cars to squeeze perhaps a few HP out of their cars, the Porsche Club 928 Germany is offering special deals for their members to add cats to their older non-cat equipped cars. Interesting.
The exaust and compression wheren't that much better.
>> Compression is a major contribution to power. If more air (oxygen) and fuel are compressed, more power is produced. This is why superchargers and turbochargers add power.
The valve's size was the same.
>> Wrong, the Euro S has larger valves (same size as 944s, the 928 CIS and L-Jet engine's valves are actually smaller than the 944!). The intake tubes on the Euro S motor are larger, the throttle housing is about 3.25 inch in diameter vs. 2.5 inch for the 928 CIS and L-jet engine. Better breathing, larger valves, higher compression = more HP.
The ignition system was the exact same.
>> Only from '80 - 83 was the same ignition used. The Euro S from '84 - 86 used EZK and a dual cap distributor (4 plug wire each) borrowed from the two plug per cylinder 3.6 liter 911s.
>> Euro S cams were more radical, the low-end power was less but after 3K RPM the power really kicks in. So, in town driving you won't feel much difference unless you really wind it up. If you put Euro S cams on an unchanged US engine, you probably wouldn't get that much more power due to the more restrictive intake and lower compression.
What the intake and fuel control on the Euro S the same as the Euro of the same year?
>> From '80 - '83 they were both CIS K-Jetronic (only used in the US market from '78 to '79). LH-Jetronic was used from '84 onwards. The US didn't see LH untill '85 with the advent of the 32 valve engine (that was still rated at less HP than the 16 valve Euro motor).
The Euro S motor wasn't spec'd to pass US emissions. A little known fact, in '85 and '86, Germany and other European countries were starting to provide tax incentives for the purchase of optional catalytic converters. A cat equipped 928 Euro in '85 or '86 used the 32 valve US motor.
While we read about listers removing cats from their cars to squeeze perhaps a few HP out of their cars, the Porsche Club 928 Germany is offering special deals for their members to add cats to their older non-cat equipped cars. Interesting.
06-13-2003, 09:53 PM
#4
Nordschleife Master
Thread Starter
(Editing, I removed the old post here. I did some more reading. Opps)
Any clue as to why the USS didn't have the same valve size as the Euro S?
How does the J-jetronic intake mannafold compare to the K-jetronic intake mannafold?
Thank you.
Any clue as to why the USS didn't have the same valve size as the Euro S?
How does the J-jetronic intake mannafold compare to the K-jetronic intake mannafold?
Thank you.
06-13-2003, 10:29 PM
#5
I think there was a cam change with the '80 4.5 Euros that may have offset some gains from C.R.;
the 78-79 cams were a more "radical?" grind than most of the later ones. 9HP isn't a terrible gain for a little better C.R. and that is also peak advertised gain at a given RPM who's to kno what type of gains this may have made thru the entire RPM range without dyno testing.
If you're thinking of dropping an early euro S engine in your '83, you've got some FI things you'll need to sort out 1st.
the 78-79 cams were a more "radical?" grind than most of the later ones. 9HP isn't a terrible gain for a little better C.R. and that is also peak advertised gain at a given RPM who's to kno what type of gains this may have made thru the entire RPM range without dyno testing.
If you're thinking of dropping an early euro S engine in your '83, you've got some FI things you'll need to sort out 1st.
06-13-2003, 10:52 PM
#6
Addict
Rennlist Member
Rennlist Member
Any clue as to why the US didn't have the same valve size as the Euro S?
>> Yes. The Porsche engineers worked very hard to come up with an engine that would meet smog requirements and get it federalized. The US had 55 mph speed limits and even the "wimpy" US Spec 234 HP L-Jetronic engine would kick-*** against the Detroit irong of that day.
a. they didn't need to
b. the production numbers didn't justify it
How does the J-jetronic intake mannafold compare to the K-jetronic intake mannafold?
>> The non-Euro S CIS intake manifold and throttle housing are identical in size to the US-spec L-Jet manifolds. The only differences are the cold-start warm-up and fittings for the fuel injectors.
There is marginal to zero benefit to consider using parts from a Euro '78 - '79 motor or a non-S Euro '80 - '83 motor to hop up an US-spec CIS or L-jet engine.
>> Yes. The Porsche engineers worked very hard to come up with an engine that would meet smog requirements and get it federalized. The US had 55 mph speed limits and even the "wimpy" US Spec 234 HP L-Jetronic engine would kick-*** against the Detroit irong of that day.
a. they didn't need to
b. the production numbers didn't justify it
How does the J-jetronic intake mannafold compare to the K-jetronic intake mannafold?
>> The non-Euro S CIS intake manifold and throttle housing are identical in size to the US-spec L-Jet manifolds. The only differences are the cold-start warm-up and fittings for the fuel injectors.
There is marginal to zero benefit to consider using parts from a Euro '78 - '79 motor or a non-S Euro '80 - '83 motor to hop up an US-spec CIS or L-jet engine.
06-13-2003, 11:07 PM
#7
Nordschleife Master
Thread Starter
Is the 80-83 Euro S intake manafold and throtal body bigger than the plain old Euro, or US?
It seems rather pointless to keep the valves smaller. Porsche has to make a diffrent casting on the head for the US S anyways, why not make it with the larger valve size? Porsche discontinued the 4.5l engine in the US, and already had the basis for the larger valve head in the EuroS. Porsche was already makeing everything the head neaded, except the lower compression head. Compared to what Porsche actualy did, the only additional expensice would be if a dealership needed the larger valves for a waranty replacement, they couldn't use the already shiped to the US smaller valves.
As I understand it, the larger valves shouldn't hurt emissions. The larger valves should help proformance all the way around, includeing torque, something Chevy 350 had the 928 beat at. (This annoys me more than a bit...)
It seems rather pointless to keep the valves smaller. Porsche has to make a diffrent casting on the head for the US S anyways, why not make it with the larger valve size? Porsche discontinued the 4.5l engine in the US, and already had the basis for the larger valve head in the EuroS. Porsche was already makeing everything the head neaded, except the lower compression head. Compared to what Porsche actualy did, the only additional expensice would be if a dealership needed the larger valves for a waranty replacement, they couldn't use the already shiped to the US smaller valves.
As I understand it, the larger valves shouldn't hurt emissions. The larger valves should help proformance all the way around, includeing torque, something Chevy 350 had the 928 beat at. (This annoys me more than a bit...)
Trending Topics
06-14-2003, 12:10 AM
#8
There's an old adage: "There's no replacement for displacement". The Porsche 4.5 and 4.7 are roughly 273 and 290 cubic inch compared to the Chevy's 350. Bore/stroke ratio will make a difference in an engine's power profile, and an engine can be built or tuned for higher torque in a given RPM range.
The Euro S engines used "bigger" everything; cams,valves,manifold runners, T.B., etc. All of the intake components have to be matched for best performance. Mixing and matching can have no noticable effect or can cause poor drivability and flatspots or just loss of power. Having the "smaller" intake set on the 4.7 US engines will produce a higher intake tract velocity and improve cylinder filling in the lower-mid range at the cost of high RPM breathing, and can improve emmissions in the lower ranges where it's tested. THis may be the very reasong they didn't use the Euro S components on the US 4.7L cars.
The Euro S engines used "bigger" everything; cams,valves,manifold runners, T.B., etc. All of the intake components have to be matched for best performance. Mixing and matching can have no noticable effect or can cause poor drivability and flatspots or just loss of power. Having the "smaller" intake set on the 4.7 US engines will produce a higher intake tract velocity and improve cylinder filling in the lower-mid range at the cost of high RPM breathing, and can improve emmissions in the lower ranges where it's tested. THis may be the very reasong they didn't use the Euro S components on the US 4.7L cars.
