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Stampedetrail
Joined: 29 May 2005 Posts: 274 Location: Fairbanks, Alaska
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Posted: Wed May 17, 2006 12:41 pm Post subject: The pros and cons of going carbuerated? |
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Some of you no doubt have switched to carbueration as opposed to the stock fuel injection. Is this wise? Is there a benefit in power? The simplicity and reliability of carbueration in obvious, but how can you get as precise a fuel/air mixture with this configuration? Or am I all wrong? & what about fuel economy? Just a thought. _________________ 1977.5 924 "Martini" head / New Old Stock rebuild
1985.5 944 Why? Because I can. |
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Lizard
Joined: 03 Nov 2002 Posts: 9364 Location: Abbotsford BC. Canada
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Posted: Wed May 17, 2006 1:11 pm Post subject: |
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I wouldnt call carbs really reliable personally,
as per fuel economy, it will go straight downhill.
as per power, abit over stock not much though.
a better solution is to convert to EFi _________________ 3 928s, |
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Khal
Joined: 26 Sep 2003 Posts: 4869 Location: Sunny and lovely interior BC, Canada
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Posted: Wed May 17, 2006 3:10 pm Post subject: |
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I think Vince has gone to carb's at least once before. I pretty sure Applebit did, too. Maybe others..?
Can't imagine why you'd do it unless you're looking to do some sort of performance modification that requires carb's or works particularly well with them.
Otherwise I'd be inclined to see it as whole lot of unnecessary expense and hassle.
There's a good reason why nearly every modern car on the planet went to fuel injection and, in particular, electronic fuel injection... 'cause carb's are sh*t and fuel injection is good! _________________ '80 924 Turbo |
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Llamaguy
Joined: 02 Jul 2003 Posts: 711 Location: Indiana
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Posted: Wed May 17, 2006 7:10 pm Post subject: |
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I think there were a couple who used some weird, expensive, side-draft carbs that might get you some where on a '77, but it wouldn't be worth it to lose all the reliabilty of FI or EFI _________________ 1987 924S Guards Red
1997 Suzuki Tl1000 Supersport |
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Peter_in_AU
Joined: 29 Jul 2001 Posts: 2743 Location: Sydney, Australia
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Posted: Wed May 17, 2006 7:30 pm Post subject: |
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If you love the smell of stale petrol everytime you get into the car or you only drive the car at wide-open-throttle then carbs are for you.
If you use the car on the road forget them. If you want to upgrade then go EFI. Carbs belong on `56 Chevys. _________________ 1979 924 (Gone to a better place)
1974 Lotus 7 S4 "Big Valve" Twin-cam (waiting)
1982 924 (As featured on Wikipedia)
Learn to love your multimeter and may the search be with you |
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timstar92404
Joined: 22 Sep 2004 Posts: 2075 Location: richmond BC
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Posted: Wed May 17, 2006 9:52 pm Post subject: |
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the only pro I can think of is that they look cool and the engine area looks much cleaner with all the CIS removed. _________________ 78 924 sold.
85.5 944 |
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Vince Ponz
Joined: 02 Nov 2002 Posts: 3581 Location: Florida
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Posted: Wed May 17, 2006 10:32 pm Post subject: |
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If you have the money and time I would say go for it if it will be a track car. No, you will not be superfast but occasionally you will stay with an early 911 etc.
I have had them on with a cam and free exhasut for over 23 years. I since added 44 suspension, bars, euro pistons etc.
The 5 speed helped as I had a four speed in it which was also changed out a long time ago. Gas was hurt but not by much. HP maybe 135-140 but not much more. As a hobby it is fine. Be prepared to put in some serious money to do this. That said buy a 944 turbo.
Like the 924?............. then leave it stock if you cannot pay for it or you will sell it when you find out that it still is not fast enough. These cars are relics. Sell them if you do not love them. For those on this board you know what I mean. They come and go like flies. Mr. Timstar are those wings I see.
Really I don't want to bash anyone but be happy with what you have. I never boast about my other cars as you can see I do own a garage queen in the 87 Targa.
Sold the 924S. It will go racing next year in the 944/924S series. _________________ "Never let them see you sweat"
77.5 924 modified track car
79 931 Euro stock
88 924S SE
87 911 Targa stock |
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Vince Ponz
Joined: 02 Nov 2002 Posts: 3581 Location: Florida
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Posted: Wed May 17, 2006 10:34 pm Post subject: |
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If you have the money and time I would say go for it if it will be a track car. No, you will not be superfast but occasionally you will stay with an early 911 etc.
I have had them on with a cam and free exhasut for over 23 years. I since added 44 suspension, bars, euro pistons etc.
The 5 speed helped as I had a four speed in it which was also changed out a long time ago. Gas was hurt but not by much. HP maybe 135-140 but not much more. As a hobby it is fine. Be prepared to put in some serious money to do this. That said buy a 944 turbo.
Like the 924?............. then leave it stock if you cannot pay for it or you will sell it when you find out that it still is not fast enough. These cars are relics. Sell them if you do not love them. For those on this board you know what I mean. They come and go like flies. Mr. Timstar are those wings I see.
Really I don't want to bash anyone but be happy with what you have. I never boast about my other cars as you can see I do own a garage queen in the 87 Targa.
Sold the 924S. It will go racing next year in the 944/924S series. _________________ "Never let them see you sweat"
77.5 924 modified track car
79 931 Euro stock
88 924S SE
87 911 Targa stock |
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Vince Ponz
Joined: 02 Nov 2002 Posts: 3581 Location: Florida
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Posted: Wed May 17, 2006 10:36 pm Post subject: |
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If you have the money and time I would say go for it if it will be a track car. No, you will not be superfast but occasionally you will stay with an early 911 etc.
I have had them on with a cam and free exhasut for over 23 years. I since added 44 suspension, bars, euro pistons etc.
The 5 speed helped as I had a four speed in it which was also changed out a long time ago. Gas was hurt but not by much. HP maybe 135-140 but not much more. As a hobby it is fine. Be prepared to put in some serious money to do this. That said buy a 944 turbo.
Like the 924?............. then leave it stock if you cannot pay for it or you will sell it when you find out that it still is not fast enough. These cars are relics. Sell them if you do not love them. For those on this board you know what I mean. They come and go like flies. Mr. Timstar are those wings I see.
Really I don't want to bash anyone but be happy with what you have. I never boast about my other cars as you can see I do own a garage queen in the 87 Targa.
Sold the 924S. It will go racing next year in the 944/924S series. _________________ "Never let them see you sweat"
77.5 924 modified track car
79 931 Euro stock
88 924S SE
87 911 Targa stock |
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John Brown
Joined: 07 Nov 2002 Posts: 903 Location: Leesburg VA
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Posted: Wed May 17, 2006 10:54 pm Post subject: |
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We had MSDS headers, straight pipe to the rear, and an Inegral Cam. Added Mikuni carbs. Not really a big change.
Once again, the 924 motor demonstrates that Porsche did an excellent job making it go just fast enough to not be easily modified to keep up with the then current low end 911. The head layout is the problem. Turns out if you want to spend that amount of time and money you copy the DP engines and stick a 931 head on with appropriate pistons.
In short, the next 924 motor I want to make run fast I'm going to do other things first before messing with carbs. _________________ John
80 931 - #931 44Cup
99 Escalade - tows track cars
gone but not forgotten: original 924.org car - 82 |
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Paul
Joined: 02 Nov 2002 Posts: 9491 Location: Southeast Wisconsin
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Posted: Thu May 18, 2006 9:38 am Post subject: |
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Most carbs are more complicated than CIS and much harder to tune!
I can't tell you how many hours I've spent of my life trying to tune Webers and Mikunis.... _________________ White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy. |
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sequential
Joined: 18 Nov 2005 Posts: 500 Location: BANNED
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Posted: Thu May 18, 2006 11:56 am Post subject: |
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I must say it is impossible not to pickup HP by going to multi -side draft carbs cams and exhaust. over cis . i Do believe it is possible with mikunis
not to pick up HP. Has to be the worst High performance carbs ever.
In the past i have used mik, webers , dellorto , holley on vw ,audi and porsche motors and find the weber to be the best at hp and the dellorto TO offer the best overall performance. we have always lost power going to mikuni carbs so had binned them a long time ago.
If you use weber carbs you will need dyno tme to correctly jet the thing .
STAY AWAY FROM MIKUNI'S.................
the 924 engine will respond best to CR increase , this is a must with any mods. _________________ 928 gts prototype
baby blue engine block
steam in 1,2,3,4 sometimes
cold star issues while on stands
112 whp with new 4 valve head and MIS 2 |
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Stampedetrail
Joined: 29 May 2005 Posts: 274 Location: Fairbanks, Alaska
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Posted: Thu May 18, 2006 5:35 pm Post subject: |
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Actually, 140 HP is pretty good considering the engine size. CR will go up, eventually, which is something I did when I rebuilt the motor of my 1972 Toronado (decommissioned battleship). When it is rebuilt I'd like to pick up a few ponies but dont want to lose a lot of positive features for little gain. At the moment, the carb is looking pretty good, as a nice-looking DELLORTO DRLA 36 sits on Ebay for $275-400--- fuel injectors are about $200, plus you have to worry about the electric pump going out, futzing with the fuel distributor maybe, etc. And no way in hell am I buying a 944 haha.
EFI sounds interesting but how do you go about it? Rip it out of an existing modern car & do a ton of welding on it or what's the deal with it, just out of curiosity? _________________ 1977.5 924 "Martini" head / New Old Stock rebuild
1985.5 944 Why? Because I can. |
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stexch
Joined: 05 Dec 2003 Posts: 90 Location: Mankato, KS, USA
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Posted: Tue May 23, 2006 6:02 am Post subject: |
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Don't try to salvage an electronic fuel injection system from another car and install it. Instead, buy a Megasquirt kit. Hire someone to install it that can give references. Get a written estimate in advance. |
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Stampedetrail
Joined: 29 May 2005 Posts: 274 Location: Fairbanks, Alaska
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Posted: Tue May 23, 2006 5:28 pm Post subject: |
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stexch wrote: | Don't try to salvage an electronic fuel injection system from another car and install it. |
That sounds quite interesting, though. The fuel injection on the 924 is antiquated primarily because of the injectors themselves. Why couldn't somebody upgrade them? Have you seen this attempted? _________________ 1977.5 924 "Martini" head / New Old Stock rebuild
1985.5 944 Why? Because I can. |
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